Life Cycle Assessment of Micro-Activated Flux Tungsten Inert Gas Welding and Conventional Tungsten Inert Gas Welding: A Case Study

Life Cycle Assessment of Micro-Activated Flux Tungsten Inert Gas Welding and Conventional Tungsten Inert Gas Welding: A Case Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Life Cycle Assessment of Micro-Activated Flux Tungsten Inert Gas Welding and Conventional Tungsten Inert Gas Welding: A Case Study Mahdi Mazloom Farsibaf, Abolfazl Moradian Baghsiah, Hossein Feiz Arefy, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5987969/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Welding methods and equipment have evolved over the years with advancements in human lifestyles and environmental needs. Among these, Conventional Gas Tungsten Inert Gas (C-TIG) Welding stands out because of its specialized applications and is recognized for its importance in manufacturing. However, the low depth of penetration (DOP) in thick sheet metals has necessitated the development of assisted methods, such as activating fluxes in the Activated TIG (A-TIG) process. This study conducts a comparative sustainability analysis of A-TIG and C-TIG welding processes. A-TIG utilizes a TiO₂-based flux to enhance weld penetration. A Life Cycle Assessment (LCA) was performed using the Ecoinvent 3 database and EPD 2018 and ReCiPe 2016 Endpoint (H) methodologies. Results indicate that A-TIG exhibits higher impacts in photochemical oxidation and water scarcity due to TiO₂ flux preparation and methanol usage. C-TIG shows higher impacts in acidification, eutrophication, global warming potential (GWP), abiotic depletion of elements (ADE), abiotic depletion of fossil fuels (ADF), and ozone layer depletion because its energy-intensive nature requires 70% more electricity. Endpoint modeling identifies human health as the most affected category, with C-TIG contributing 62% more damage due to emissions and energy use. Despite A-TIG’s improved energy efficiency and weld quality, its flux reliance introduces specific environmental trade-offs. This research highlights the need to balance weld quality and ecological sustainability for greener manufacturing practices. Life cycle assessment(LCA) welding A-TIG C-TIG energy consumption Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction Welding is the most common method used for joining two metals. Among the various welding processes, gas tungsten arc welding (GTAW), also known as conventional TIG (C-TIG) welding, is widely employed in industrial applications. C-TIG is classified as a fusion welding process, where an electric arc is generated to melt the base metal and a non-consumable tungsten electrode. The electric arc in welding releases energy in an ionized gas environment, generating sufficient heat to melt the base metal and form a weld pool. This pool is shielded from atmospheric contamination by inert gases, primarily argon or helium. Upon solidification, the weld bead is formed. The TIG process is highly versatile and finds extensive use in industries such as aerospace, construction, oil and gas, shipbuilding, and nuclear power [1, 2]. While C-TIG welding is celebrated for its precision and ability to produce high-quality welds, it has notable limitations, including limited weld penetration, high heat input, and low productivity, particularly when working with alloys of varying thicknesses [3, 4]. Additionally, achieving a desirable DOP in C-TIG requires edge preparation, a post-process step that is not necessary in A-TIG[5, 6]. To address these challenges, researchers have explored innovative approaches, such as ultrasonic vibration and activating fluxes composed of nano- and micro-sized metal oxide particles[7, 8]. These advancements aim to improve welding efficiency and mitigate the inherent limitations of conventional TIG methods. The flux-assisted method involves applying a thin layer of flux to the surface of the base metal before welding[9]. This technique significantly increases penetration depth, achieving 1.5 to 2.5 times greater depth compared to conventional TIG welding [10, 11]. Among the metal oxides used in A-TIG, TiO₂, and SiO₂ are reported to be the most effective fluxes. They help reduce weld bead width and significantly enhance weld penetration when used with GTAW [12]. The use of metal oxide fluxes is common in various other manufacturing methods[13, 14]. The welding industry, a vital segment of the metallurgical sector, has faced growing criticism in recent decades for its substantial consumption of raw materials. This has led to ecosystem degradation, loss of biodiversity, and pollution of water and soil. Sattarpanah et al. [15] used finite element analysis to evaluate the thermal behavior of TIG-welded stainless steels. Their study revealed a clear relationship between welding speed, bead width, and penetration depth. An increase in current and a decrease in welding speed result in both an increase in weld bead width and greater penetration depth. This occurs because the input energy, derived from the increased current, is higher, which in turn transfers more energy to the material, leading to a larger molten volume. In the USA, sustainable manufacturing was defined as the process of producing goods in ways that reduce environmental harm, conserve energy and resources, prioritize the safety of workers, communities, and consumers, and maintain economic viability [16]. Sustainable development in manufacturing industries provides a means to not only minimize environmental impacts but also enhance economic and social performance [17]. Grasping the essence of sustainable development hinges on recognizing the life-cycle concept as its most critical element[18]. The industrial sector stands as one of the most resource-intensive and polluting domains, contributing to over 40% of global energy consumption[19]. The economic importance of welding processes in Europe and their influence on the European industry have been significant for several years now. Numerous studies have examined the economic impact of welding processes and explored methods or tools to reduce costs [20]. Additionally, approaches have been developed to assist in selecting the most cost-effective welding process based on economic factors. This study compares micro-sized A-TIG and C-TIG bead-on-plate welding in terms of key performance metrics and environmental considerations. The analysis also addresses the total production time, including preprocessing time for flux preparation, while evaluating the direct and indirect energy consumption associated with each method. These metrics form the foundation for a comparative assessment aimed at identifying resource-efficient and sustainable practices. The focus of the study is on energy consumption, ecological footprint, and overall sustainability. Both processes were evaluated from economic and environmental perspectives, with an ecological assessment based on critical factors such as electrical energy usage, shielding gases, and micro-sized metal oxide fluxes, considering their impacts on health, ecosystems, and resources. The analysis utilized the Ecoinvent 3 database within SimaPro 9.2. To our knowledge, no previous study has experimentally compared the LCA of these two welding methods. This research provides new insights into the environmental costs of each approach through a case study using SS304L, a widely applied base metal. 2. Methods This section details the methodology employed in the case study, emphasizing the defined scope of the LCA, the two distinct welding processes under evaluation, the criteria for ensuring comparable specimens, and the measurement techniques utilized. 2.1. C-TIG and A-TIG Welding Experiments The C-TIG technique employed in this research uses a non-consumable tungsten electrode to create an arc for welding, with Argon serving as an inert shielding gas to protect the weld pool from contamination. No filler material was used, and the welding process was applied to fabricate a 100-millimeter specimen. In the A-TIG process, a TiO₂ micro-size (30 microns) activating flux was applied to the workpiece surface prior to C-TIG welding. The flux improves heat input, resulting in deeper weld penetration, better control over the weld pool, and enhanced weld quality [21, 22]. This process allows for reduced heat input, which helps minimize distortion and improves the DOP. To prepare the flux, 1 gram of TiO₂ metal oxide was combined with 5 milligrams of methanol and stirred on a magnetic hot plate stirrer at a rotation speed of 600 RPM for 20 minutes in ambient air(20 o C). The flux was then applied to the base metal (SS304L) to a depth of 0.025 mm along the intended weld bead before bead-on-plate TIG welding. A GamElectric PSQ250 AC/DC welding machine was used for the deposition process, featuring a single-axis motion system to regulate the welding speed, and a three-phase JAM 300 tariff meter was employed to measure the electricity consumption of the stirrer, as illustrated in Figure 1. This study aims to compare the LCA of specimens with nearly identical DOP achieved using A-TIG and C-TIG processes. Screening experiments based on prior studies were conducted for both methods to establish comparable welding parameters, ensuring almost identical DOP as the evaluation criterion. Specifically, a DOP of 1.7 mm was achieved with different welding currents: 170 A for C-TIG and 100 A for A-TIG, resulting in distinct environmental impacts. The ecological implications of micro-activated fluxes were assessed by evaluating the production of metal oxides in micro size, the energy consumption of the magnetic hot plate stirrer, and the methanol used in flux preparation. These analyses were informed by data obtained from laboratory experiments, numerical calculations, and the Ecoinvent 3 database. Table 1 provides a detailed presentation of the input parameters utilized in both welding methods, highlighting the distinctions in energy consumption, and process characteristics. Table.1. C-TIG and A-TIG welding input parameters Welding method Parameters C-TIG A-TIG Micro flux - TiO 2 Current (A) 170 100 Gas Flow (L/min) 10 10 Shielding Gas (99.9% purity) Ar Ar Travel Speed (cm/min) 145 145 Gap(mm) 3 3 Electrode Diameter(mm) 2.4 2.4 Torch Angle(Degree) 90 90 Gas Nozzle Diameter(mm) 6 6 Electrode Tip Angle(Degree) 30 30 Figure 2 provides an overview of the case study specimens analyzed. Figure 2(a) highlights the 100 mm bead-on-plate samples, illustrating the experimental setup. Magnified cross-sectional views of the welded samples in Figures 2(b) and 2(c) reveal the identical DOP achieved by the C-TIG and A-TIG welding processes, emphasizing their comparable weld penetration performance. 2.2 Life Cycle Assessment LCA is an effective method for evaluating the environmental impact of a product, process, or service across its entire life cycle, from resource extraction to final disposal [23]. It helps manufacturers identify areas for improvement to make their processes more sustainable. LCA allows for the comparison of two systems delivering the same service or product, as defined by the functional unit (FU). It provides data on environmental footprints, such as carbon emissions, and supports the creation of environmental statements or eco-labeling to promote sustainable practices. Based on the ISO 14040 standard LCA has four stages [24]. The first one is called Goal and Scope Definition; it defines the purpose and the system boundary of the assessment. The second is the Inventory Analysis, Life Cycle Inventory (LCI), which involves data collection on all inputs and outputs throughout each stage of the life cycle. These data create the basis for assessing the impact. The third step involves the life cycle Impact Assessment (LCIA), which changes the collected data into quantifiable environmental impact categories, such as GWP. The last stage is the Interpretation, analysis, and evaluation of results concerning the stated goals, such as recommendations and identification of hotspots [25]. The environmental analysis section of this study assesses the lifecycle impacts of specimens produced using C-TIG and A-TIG welding techniques. It outlines the scope and objectives, describes the Life Cycle Inventory (LCI), and conducts a comprehensive LCA. The FU for the comparison comprises two stainless steel SS304L components, each measuring 100 × 50 × 5 mm, welded using both methods to achieve a uniform Depth of Penetration (DOP) of 1.75 mm. The LCA evaluates the environmental performance of these welding processes for a 100 mm weld length, as illustrated in Figure 2(a). This assessment provides a clear basis for comparing the environmental impacts of the two methods in achieving identical welding outcomes. Figure 3 . depicts the system boundaries defined for the LCA, encompassing the entire life cycle from raw material processing to the final part. Data collection includes calculating the primary process energy and auxiliary energy for equipment using direct and indirect methods, such as machine tags or kWh meters. Supplementary data were sourced from the Ecoinvent 3 database, ensuring that the selected data reflect the study's location in Iran. A systematic approach was employed to calculate the energy consumption during the welding processes of A-TIG and C-TIG. The energy consumption was determined using Equation 1, which accounts for the efficiency of the welding machine. This equation represents the effective energy consumption in Watt-hours (Wh), the voltage in volts, the current in amperes, the welding duration in hours, and the welding machine efficiency, assumed to be 85%. This approach ensured an accurate representation of energy inputs during the welding phase. In the C-TIG process, the voltage was 16.7 V and the current was 170 A, while in the A-TIG process, the voltage was 13.9 V and the current was 100 A. With the travel speed assumed to be constant, resulting in a welding time of 4.13 seconds, and an efficiency factor of 0.85, the energy consumption was calculated using Equation 1. The results showed that the welding energy consumption for C-TIG was 2304.6 Wh, while for A-TIG it was 1128.4 Wh. In both welding methods, the shielding gas used to protect the weld pool was measured using a flowmeter, as the gas flow rate is a critical input variable in the welding process. A flow rate of 10 liters per minute was selected based on a review of relevant literature. To calculate the shielding gas usage, the flow rate was multiplied by the welding time to determine the volume of gas used, which was then converted to mass by multiplying it by the density of Argon (0.001784 kg/L). This calculation resulted in approximately 0.00123 kg of Argon used per weld. The environmental impact of the shielding gas was reported separately for each welding method to ensure a comprehensive assessment of energy inputs. The data collected for the LCI was standardized to an FU of a 100-millimeter welded sample for both methods, facilitating a consistent comparison of environmental impacts. Table 2 provides a summary of energy consumption for welding the samples. In the C-TIG process, the energy consumption includes the entire hot rolling process, which encompasses billet rolling for base metal production. Conversely, the A-TIG process accounts for an additional stage of flux preparation, with the required electricity measured using a three-phase JAM 300 tariff meter. The quantities of methanol and metal oxide used were determined from published studies, weighed, and their environmental impacts evaluated using the database. Table 2. LCI for C-TIG and A-TIG fabricated specimen Process C-TIG A-TIG Amount Unit Type of Data Amount Unit Type of Data Hot Rolling 0.196 kg Ecoinvent 3 0.196 kg Ecoinvent 3 Arc welding 0.23035 kWh Calculated 0.11282 kWh Calculated Shielding Gas(Argon) 0.00123 kg Measured-Ecoinvent 3 0.00123 kg Measured-Ecoinvent 3 Micro-size TiO 2 powder - - - 0.001 kg Ecoinvent 3 Water - - - 0.0015 M 3 Ecoinvent 3 Methanol - - - 3.95 g Ecoinvent 3 Electricity (flux stirrer) - - - 0.01 kWh Measured To conduct an LCA of the environmental impacts associated with the manufacturing process, multiple impact categories are analyzed. More details on these categories are provided in the results and discussion section. These indicators align with the EPD2018 methodology, ensuring a comprehensive evaluation of environmental performance [26]. Of the databases available, Ecoinvent3-allocation, cut-off by classification library, and EPD2018 and ReCiPe 2016 Midpoint(H) methods were applied, as part of the standard LCA process. The impact categories of the EPD 2018 methodology are shown in Table 3. Table 3. Impact indicators of EPD 2018 for A-TIG and C-TIG Impact Category Unit A-TIG C-TIG Acidification(fate not included) kg SO 2 eq. 0.000775 0.000993 Eutrophication kg PO 4 ---- eq. 0.000151 0.000176 Global Warming(GWP 100a) kg CO 2 eq. 0.195 0.242 Photochemical oxidation kg NMVOC 0.00155 0.000745 Abiotic depletion, elements kg Sb eq. 5.32E-7 9.43E-7 Abiotic depletion, fossil fuels MJ 2.83 3.45 Water scarcity M 3 eq. 0.278 0.181 Ozone layer depletion(ODP) kg CFC-11 eq. 2.08E-8 2.56E-8 Results and Discussion The results of the case study, obtained from the LCA and using the EPD2018 impact categories, are illustrated in Figure 4. The analysis is based on the 100 mm welded FU and the data from the LCI for both A-TIG and C-TIG processes. The environmental impacts of the C-TIG and A-TIG welding methods were analyzed, revealing notable distinctions due to differences in process inputs and energy requirements. A-TIG employed a TiO₂ activating flux, which enhanced process efficiency by improving heat input and weld penetration. C-TIG process demonstrated higher impacts across all the categories of acidification, eutrophication, global warming, photochemical oxidation, abiotic depletion of elements, abiotic depletion of fossil fuels, Water scarcity, and ozone layer depletion. These differences are attributed to the additional energy required for the C-TIG process, as its current level is 70% higher than that of A-TIG. As illustrated in Figure 4, the C-TIG process exhibited higher impacts across most categories, with C-TIG impact in acidification potential, which was 17% greater than that of A-TIG equivalent to 0.000158 kg SO 2 . Acidification potential, measured in SO₂ equivalents, highlights the environmental burden of emitted sulfur and nitrogen compounds, which react in the atmosphere to form sulfuric and nitric acids [27]. These acids contribute to soil and water pollution through acid rain, which depletes soil nutrients, harms plant and animal life, and disrupts ecosystems [9]. The higher acidification potential of C-TIG underscores its energy-intensive nature and its greater environmental impact compared to A-TIG. Eutrophication impacts were observed to be 14.5% higher in C-TIG, likely resulting from the increased energy consumption associated with this welding process. Eutrophication occurs when excess nutrients, particularly nitrogen and phosphorus compounds, enter water bodies or soil systems, leading to several environmental issues, such as excessive algae growth that blocks sunlight and disrupts aquatic ecosystems, reduced oxygen levels in water due to the decomposition of organic matter, fish mortality, and overall ecosystem changes, including reduced biodiversity and habitat degradation [28]. The higher energy usage in C-TIG, especially when powered by fossil fuel-based electricity grids, contributes to nutrient enrichment in water bodies. This is primarily due to the release of nitrogen oxides (NOx) and sulfur oxides (SOx) during fuel combustion, which can be deposited into water systems through atmospheric processes and rainwater. The GWP measures the extent to which various greenhouse gases contribute to atmospheric warming over a specific time, typically 100 years, relative to CO₂, which serves as the reference gas with a GWP of gases like methane (CH₄), nitrous oxide (N₂O), and chlorofluorocarbons (CFCs) have significantly higher GWPs due to their greater heat-trapping capacities and atmospheric lifespans. This metric facilitates standardized comparisons of greenhouse gases, enabling the assessment of their relative impacts on climate change[29]. In carbon footprint analysis and emissions reporting, GWP converts the warming effects of all greenhouse gas emissions into CO₂ equivalents. For instance, the C-TIG process exhibits a 19.4% higher GWP than A-TIG, mainly due to its energy-intensive nature, where the welding current requirement is 1.7 times greater in the case study. This increased energy demand, particularly in fossil fuel-reliant regions like Iran, results in higher CO₂ emissions from fuel combustion. Additionally, natural gas extraction and distribution processes often lead to methane leaks, which have a GWP 28–36 times that of CO₂ over 100 years. The compounded effect of increased energy consumption and methane emissions substantially elevates the GWP of processes like C-TIG, highlighting the environmental cost of inefficiencies in energy use. Among the environmental categories, ADE in the C-TIG process showed the largest difference, with an increase of 43.6%, corresponding to an additional 4.11E-7 Sb-equivalent per FU. ADE measures the reduction of non-renewable mineral resources, such as metals and rare elements, due to human activities like mining and industrial processes [30]. This depletion is especially significant in energy generation, where the extraction and processing of raw materials, including fossil fuels for power plants, contribute substantially to ADE. The extraction of natural gas—a major source of power in Iran—involves resource-intensive processes, including the mining of metals such as steel, aluminum, and copper. These materials are essential for the infrastructure used in gas extraction, transport, and electricity generation. As these metals are mined, non-renewable elements are depleted, thus contributing directly to ADE. In the case of the C-TIG welding process, the higher energy consumption amplifies the ADE impact. This process relies heavily on electricity, which in regions like Iran, where natural gas is the predominant energy source, is largely generated from natural gas combustion. Consequently, the increased energy demand for C-TIG further accelerates the extraction of natural gas, leading to higher ADE values associated with the welding process. The observed 17.9% higher impact in ADF for the C-TIG process can primarily be attributed to its higher energy consumption compared to A-TIG. The C-TIG process, which requires more electricity for its welding operations, leads to a greater demand for energy production. In regions like Iran, where electricity is largely generated through natural gas combustion, this results in increased extraction and consumption of fossil fuels, particularly natural gas, which is a key contributor to ADF[31]. The increased energy demand for the C-TIG process means more fossil fuels are burned to produce the required electricity, thus leading to higher fossil fuel depletion. This impact is directly correlated to the energy-intensive nature of the C-TIG process, where more energy per unit of welding is consumed. Additionally, since natural gas extraction and combustion are resource-heavy activities, they deplete non-renewable fossil fuel reserves at a higher rate. Infrastructure for gas extraction, such as drilling rigs and pipelines, requires metals and other resources that also contribute to fossil fuel depletion. Therefore, the C-TIG's energy dependence exacerbates the depletion of fossil fuels, making it more impactful than the A-TIG process in terms of ADF. The higher ozone depletion impact of 18.7% in the C-TIG process was primarily attributed to emissions from fossil fuel-based energy generation. This process can release trace substances or generate indirect emissions that contribute to ozone layer depletion, although these effects are minor compared to those caused by industrial refrigerants or solvents [32]. The observed difference is more likely a result of the increased energy consumption in C-TIG, which intensifies emissions associated with electricity generation in regions reliant on fossil fuels. Conversely, A-TIG, a promising alternative to conventional methods, exhibits higher ecological impacts in only two categories: photochemical oxidation and water scarcity. This highlights its potential for broader environmental benefits while identifying specific areas where further optimization is needed to enhance its sustainability profile. Titanium dioxide (TiO 2 ) occurs naturally in various crystalline forms, with rutile being the most common. In Iran, the sulfate process is a common method for TiO 2 production. The typical particle size of produced TiO 2 in Iran varies but often falls within the sub-micron to several micron range. To achieve a particle size of 30 microns, techniques like grinding (e.g., ball milling, jet milling) and classification (e.g., sieving, air classification) can be employed. However, careful consideration must be given to factors such as particle size distribution, product quality, and economic feasibility when selecting and implementing these methods [33]. Photochemical oxidation, also known as ozone creation potential, refers to the formation of ground-level ozone (tropospheric ozone) through chemical reactions involving nitrogen oxides (NOx) and volatile organic compounds (VOCs) under ultraviolet (UV) radiation. This process is a key contributor to summer smog, a type of air pollution that can adversely affect human respiratory health, damage vegetation, and reduce agricultural productivity [34]. The impact of photochemical oxidation was found to be 52% higher in A-TIG compared to C-TIG, highlighting the environmental challenges associated with the additional flux preparation in A-TIG. The emission of methanol used in the process and the extra energy consumption required for metal oxide and solvent preparation contribute significantly to this impact. Furthermore, A-TIG's reliance on fossil fuel-based energy for flux preparation leads to increased NOx and VOC emissions during electricity generation and related industrial activities. These emissions intensify the formation of photochemical smog, exacerbating air quality issues and contributing to environmental degradation. The 35.1% higher impact of A-TIG on water scarcity highlights the significant role of water usage in its production processes [35]. This disparity is primarily attributed to the water-intensive activities involved in the extraction and processing of ilmenite, as well as the preparation of TiO₂ micro-powder used as flux. The mining and beneficiation of ilmenite require substantial water resources for ore washing and separation. Additionally, the chemical treatments and refinement processes for TiO₂ production consume considerable amounts of water, contributing further to this impact. These findings emphasize the need for improved water management and resource optimization in the production and application of TiO₂-based flux materials to reduce their environmental footprint. While A-TIG delivers superior weld quality and efficiency, its overall environmental footprint is comparatively lower. In contrast, C-TIG's energy-intensive operation results in significantly higher environmental impacts across most of the evaluated categories. This underscores the importance of considering both performance and sustainability when selecting welding methods. Using the ReCiPe 2016 methodology, the results of this study are simplified into endpoint categories to enhance clarity and facilitate communication of environmental impacts. Endpoint modeling translates complex environmental effects into measurable damage across three primary areas: human health, ecosystems, and resources. The Human Health category reflects the potential impact of environmental burdens on human well-being, such as the increase in disease or mortality rates due to air pollution, toxic emissions, and greenhouse gases. In this study, human health damage is influenced heavily by emissions from energy-intensive processes, particularly in the C-TIG method. Ecosystems evaluate the harm to biodiversity and natural habitats caused by environmental degradation, such as land use, pollution, and climate change. Ecosystem damage from the processes arises primarily from emissions that contribute to acidification, eutrophication, and habitat disruption. Resources quantify the depletion of non-renewable resources, including fossil fuels and critical minerals, which are consumed during energy production and material extraction. Resource depletion is more pronounced in energy-intensive processes like C-TIG, which rely on fossil fuel-based electricity generation. Figure 5 illustrates the environmental performance of A-TIG and C-TIG across these three endpoint indicators. By condensing the impacts into these categories, this approach provides a comparative framework that aids in understanding the trade-offs in sustainability between the two processes. It underscores the need to balance operational efficiency with environmental responsibility. The environmental impact assessment of A-TIG and C-TIG processes provides valuable insights when considering normalization results. The normalization results are presented in Figure 6, emphasizing the dominance of the human health category. The normalized values for human health reach 14.955 for A-TIG and 24.1788 for C-TIG, significantly higher than the values for ecosystems and resources, which remain below 5.0E-06 for both processes. This indicates that the human health impacts are greater in order of magnitude than in the other categories. The slightly higher value for C-TIG in the ecosystems category reflects increased emissions or energy use during the process. Meanwhile, the minimal contributions to ecosystems and resources confirm the relatively low environmental burden in these categories. Figure 6 presents the environmental impact assessment of the A-TIG welding process using the EPD 2018 methodology. The analysis reveals that, while the A-TIG process has a lower overall environmental burden compared to alternative methods, it exhibits significant impacts in specific categories due to additional pre-processing steps, such as flux usage. Natural gas combustion, primarily used for welding energy consumption, emerges as a major contributor to environmental impacts. It accounts for 83.9% of the impact in Abiotic Depletion of Elements, 47.8% in Ozone Layer Depletion, 46.4% in GWP and Abiotic Depletion of Fossil Fuels, 46.1% in Acidification, 37.1% in Eutrophication, 15.3% in Photochemical Oxidation, and 3.23% in Water Scarcity. These impacts are driven by the energy-intensive nature of the process, particularly during flux preparation and application, where natural gas plays a critical role. The TiO₂ micro-powder used as an activating flux in A-TIG welding significantly impacts acidification (22.6%) and eutrophication, GWP, and ADF (18.1%–19.1%). These impacts result from the energy-intensive processes of titanium dioxide production, which include mining, extraction, and refining of raw materials. Emissions of nitrogen and sulfur compounds during these operations contribute to acidification by forming acidic substances in the atmosphere. Similarly, wastewater and nutrient runoff from TiO₂ production contribute to eutrophication, leading to issues like algae blooms and oxygen depletion in aquatic ecosystems. Methanol, employed in flux preparation, is the largest contributor to photochemical oxidation, accounting for 60% of the impact in this category. Methanol's environmental footprint arises from its production, which depends on fossil fuel-derived feedstocks, and its emissions during usage, which include volatile organic compounds with ozone-depleting potential. Overall, the environmental impacts of A-TIG welding are significantly influenced by the materials and energy required for flux preparation and application. These findings underscore the importance of optimizing flux formulations and improving energy efficiency in the process to mitigate associated environmental burdens. Conclusion The comparative environmental assessment of A-TIG and C-TIG welding processes underscores the trade-offs between efficiency and sustainability. A-TIG demonstrates superior energy efficiency and lower overall environmental impacts; however, its dependence on TiO₂ flux results in notable burdens in specific categories such as photochemical oxidation and water scarcity. In contrast, C-TIG consistently exhibits higher environmental impacts across most evaluated categories, primarily due to its energy-intensive nature, requiring 70% more electricity than A-TIG. Key findings include: Acidification potential: C-TIG Impact is 17% higher than A-TIG, equivalent to an additional equivalent to 0.000158 kg SO 2 /FU. These acids contribute to soil and water pollution through acid rain, which depletes soil nutrients, harms plant and animal life, and disrupts ecosystems Eutrophication impacts: C-TIG Impact is 14.5% higher than A-TIG. Resulting from the increased energy consumption associated with this welding process GWP: C-TIG Impact: 19.4% higher, reflecting greater CO₂ and methane emissions from fossil fuel-based electricity. Methane, with a GWP 28–36 times higher than CO₂ over 100 years, intensifies the effect. Enhanced greenhouse gas emissions exacerbate climate change risks. ADE: C-TIG Impact: 43.6% higher than A-TIG, equivalent to an additional 4.11E-7 Sb-equivalent per FU. The energy-intensive nature of C-TIG is linked to the extraction and processing of natural gas and the use of metals like steel, copper, and aluminum in infrastructure. ADF: C-TIG Impact: 17.9% higher than A-TIG. Increased electricity demand (70% higher in C-TIG) results in more natural gas combustion, directly contributing to fossil fuel depletion. Ozone Layer Depletion in C-TIG is 18.7% higher, primarily linked to fossil fuel-based energy generation. A-TIG's photochemical oxidation impact is 52% higher than C-TIG, driven by methanol emissions, energy-intensive flux preparation, and fossil fuel reliance. These factors increase NOx and VOC emissions, contributing to ground-level ozone formation, which harms air quality, respiratory health, and agricultural productivity. The 35.1% higher impact of A-TIG on water scarcity is likely attributed to the water usage involved in the extraction of ilmenite and the preparation of TiO₂ micro-powder for flux production. Human Health: Normalized values of 14.955 (A-TIG) vs 24.1788 (C-TIG), dominated by emissions from energy-intensive operations in C-TIG. Ecosystems and Resources: Normalized values remain below 5 for both processes. Lower impacts highlight minimal burdens relative to human health. The environmental impacts of A-TIG welding are significantly influenced by natural gas combustion and the energy-intensive preparation of TiO₂ micro-powder and methanol-based flux. Natural gas contributes substantially to impacts such as abiotic depletion, GWP, and acidification, while TiO₂ production drives acidification and eutrophication through emissions and wastewater. Methanol accounts for 60% of photochemical oxidation impacts due to its fossil fuel-derived production and volatile emissions Declarations Ethics approval and consent to participate and publication This study was conducted in accordance with the ethical guidelines outlined by the Committee on Publication Ethics (COPE). All participants provided written informed consent to participate in the study . Author contributions All authors made substantial contributions to this research work. Mahdi Mazloom Farsibaf, the first author, led the material preparation, data collection, formal analysis, and methodology. He also drafted the initial version and revised the final manuscript. Abolfazl Moradian contributed significantly to the experimental design and assisted in data analysis and interpretation of the results. Dr, Amirmohammad Ghandehariun provided technical support during the experimental phase and contributed to refining the methodology. Dr Farhad Kolahan, the corresponding author, supervised the entire project, offered critical insights throughout the research, and thoroughly reviewed and revised the manuscript for important intellectual content. All authors engaged in critically revising the manuscript, provided valuable feedback on multiple drafts, and approved the final version for publication . Funding No funding was obtained for this study. Declaration of conflicting interests The authors did not receive support from any organization for the submitted work References Kumar, K., et al., A review on TIG welding technology variants and its effect on weld geometry. Materials Today: Proceedings, 2022. 50 : p. 999-1004. Chauhan, R., et al., Effect of Various Fluxes on Different Metals and Alloys in A-TIG Process: A Review. Jurnal Kejuruteraan, 2022. 34 (4): p. 543-553. Varshney, D. and K. Kumar, Structured review of papers on the use of different activating flux and welding techniques. Ain Shams Engineering Journal, 2021. 12 (3): p. 3339-3351. Kumaar, S.S. and N.N. Korra, “Effects of using oxide fluxes as activating flux on Activated flux Tungsten Inert Gas welding” – A review. Materials Today: Proceedings, 2021. 46 : p. 9503-9507. Chandrasekhar, N. and M. Vasudevan, Intelligent Modeling for Optimization of A-TIG Welding Process. Materials and Manufacturing Processes, 2010. 25 (11): p. 1341-1350. Kumar, A., et al., Investigation and enhancement of mechanical properties of SS-316 weldment using TiO2-SiO2-Al2O3 hybrid flux. International Journal on Interactive Design and Manufacturing (IJIDeM), 2024. 18 (3): p. 1557-1573. Far, M.n.S., et al., Analyzing weld bead geometry and microstructure in ultrasonic-assisted activated flux TIG welding of ST37 steel. International Journal on Interactive Design and Manufacturing (IJIDeM), 2024. Rakesh, N., et al., Effect of fluxes on weld penetration during TIG welding – A review. Materials Today: Proceedings, 2023. 72 : p. 3040-3048. Patel, D. and S. Jani, ATIG welding: a small step towards sustainable manufacturing. Advances in Materials and Processing Technologies, 2021. 7 (3): p. 514-536. Rana, H., et al., Augmentation of weld penetration by flux assisted TIG welding and its distinct variants for oxygen free copper. Journal of Materials Research and Technology, 2021. 10 : p. 138-151. Venkatesan, G., V. Muthupandi, and J. Justine, Activated TIG welding of AISI 304L using mono- and tri-component fluxes. The International Journal of Advanced Manufacturing Technology, 2017. 93 (1): p. 329-336. Ghetiya, N.D., et al., Investigating the effect of different flux combinations, welding current and speed for optimizing D/W ratio in a novel Flux zone TIG welding of SS304. International Journal on Interactive Design and Manufacturing (IJIDeM), 2024. 18 (8): p. 5515-5531. Silva, M., A.S. Ramos, and S. Simões Joining Ti6Al4V to Alumina by Diffusion Bonding Using Titanium Interlayers . Metals, 2021. 11 , DOI: 10.3390/met11111728. Galvão, I., et al., Structural analysis of aluminium-titanium-stainless steel three-layer composites produced by explosive welding. Welding in the World, 2024. 68 (11): p. 2911-2925. Sattarpanah Karganroudi, S., et al. Experimental and Numerical Analysis on TIG Arc Welding of Stainless Steel Using RSM Approach . Metals, 2021. 11 , DOI: 10.3390/met11101659. Jayal, A.D., et al., Sustainable manufacturing: Modeling and optimization challenges at the product, process and system levels. CIRP Journal of Manufacturing Science and Technology, 2010. 2 (3): p. 144-152. Khalfallah, A. and C. Leitão Sustainable Manufacturing and Green Processing Methods . Machines, 2024. 12 , DOI: 10.3390/machines12110815. Ghandehariun, A., Y. Nazzal, and H. Kishawy, Sustainable manufacturing and its application in machining processes: a review. International Journal of Global Warming, 2016. 9 (2): p. 198-228. Kokare, S., et al., Wire arc additive manufacturing of a high-strength low-alloy steel part: environmental impacts, costs, and mechanical properties. The International Journal of Advanced Manufacturing Technology, 2024. 134 (1): p. 453-475. DeBoer, B., et al., Additive, subtractive, and formative manufacturing of metal components: a life cycle assessment comparison. The International Journal of Advanced Manufacturing Technology, 2021. 115 (1): p. 413-432. Mazloomfarsibaf, M., M. Azadi Moghaddam, and F. Kolahan, The Use of Grey-Taguchi based Approach for Modeling and Heuristic Algorithm-based Method for Optimization of Flux Assisted TIG Welding Process. Journal of Computational Applied Mechanics, 2024. Azadi Moghaddam, M. and F. Kolahan, Optimization of A-TIG Welding Process Using Simulated Annealing Algorithm. Journal of Advanced Manufacturing Systems, 2020. 19 (04): p. 869-891. Cortés-Borda, D., C.M. Torres, and Á. Galán-Martín, Chapter 3 - Sustainability in products and process design , in Sustainable Design for Renewable Processes , M. Martín, Editor. 2022, Elsevier. p. 101-130. Raute, J., et al., Life cycle assessment in additive manufacturing of copper alloys—comparison between laser and electron beam. Welding in the World, 2024. 68 (12): p. 3169-3176. Environmental management — Life cycle assessment — Requirements and guidelines. [Online]. 2006 Accessed on 26 Jan 2025]; Available from: https://www.iso.org/standard/38498.html. González-González, C., et al. Environmental and Economic Analyses of TIG, MIG, MAG and SMAW Welding Processes . Metals, 2023. 13 , DOI: 10.3390/met13061094. Bolan, N., et al., Soil acidification and the liming potential of biochar. Environmental Pollution, 2023. 317 : p. 120632. Wurtsbaugh, W.A., H.W. Paerl, and W.K. Dodds, Nutrients, eutrophication and harmful algal blooms along the freshwater to marine continuum. WIREs Water, 2019. 6 (5): p. e1373. Lynch, J., et al., Demonstrating GWP*: a means of reporting warming-equivalent emissions that captures the contrasting impacts of short- and long-lived climate pollutants. Environmental Research Letters, 2020. 15 (4): p. 044023. van Oers, L., J.B. Guinée, and R. Heijungs, Abiotic resource depletion potentials (ADPs) for elements revisited—updating ultimate reserve estimates and introducing time series for production data. The International Journal of Life Cycle Assessment, 2020. 25 (2): p. 294-308. Martins, F., et al. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5987969","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":435958506,"identity":"9730c37c-c962-4dbe-be99-3806c944f7aa","order_by":0,"name":"Mahdi Mazloom Farsibaf","email":"","orcid":"","institution":"Ferdowsi University of Mashhad","correspondingAuthor":false,"prefix":"","firstName":"Mahdi","middleName":"Mazloom","lastName":"Farsibaf","suffix":""},{"id":435958507,"identity":"e074a2c8-3e24-4bd3-9d25-59dfda8e74bf","order_by":1,"name":"Abolfazl Moradian Baghsiah","email":"","orcid":"","institution":"Ferdowsi University of 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11:14:28","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":748513,"visible":true,"origin":"","legend":"\u003cp\u003eexperimental setup for C-TIG and A-TIG\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-5987969/v1/bdbec03f48098965c25c5dfc.png"},{"id":81032298,"identity":"a4c509fa-0db2-4fac-b528-44dc446f51bd","added_by":"auto","created_at":"2025-04-21 11:30:28","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":734428,"visible":true,"origin":"","legend":"\u003cp\u003eCase studies for LCA (a), and cross-section areas of \u0026nbsp;C-TIG (b) and A-TIG (c) specimens\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-5987969/v1/f6d97ade41fabf8c6d61662e.png"},{"id":81032297,"identity":"0e1e7f80-26f9-41a0-ab53-02ba49fac79d","added_by":"auto","created_at":"2025-04-21 11:30:28","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":49946,"visible":true,"origin":"","legend":"\u003cp\u003eboundaries of the system considered in LCA\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-5987969/v1/ca35571351ef3b0b02a4fced.png"},{"id":81031338,"identity":"d3596a73-63c8-48e3-9298-98f164f4fe6c","added_by":"auto","created_at":"2025-04-21 11:22:28","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":44290,"visible":true,"origin":"","legend":"\u003cp\u003eLCA results by impact category and case study according to EPD2018.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-5987969/v1/92a6d1a50c568e7825c92883.png"},{"id":81030158,"identity":"4d16983c-e42e-4366-84c0-4b38e2879d00","added_by":"auto","created_at":"2025-04-21 11:14:28","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":32914,"visible":true,"origin":"","legend":"\u003cp\u003efinal results according to the ReCiPe 2016 method Normalization\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-5987969/v1/70b25e5402214b5695b4ca73.png"},{"id":81030157,"identity":"721be978-19ce-48ea-9233-b2fe2779e55a","added_by":"auto","created_at":"2025-04-21 11:14:28","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":70626,"visible":true,"origin":"","legend":"\u003cp\u003eA-TIG EPD 2018 assessment\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-5987969/v1/c81597dbcf655c8cba894a11.png"},{"id":82730517,"identity":"a558c0f5-194a-4bb0-b4bd-f74aa300b62d","added_by":"auto","created_at":"2025-05-14 14:41:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2963427,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5987969/v1/6fbc763b-2ac9-4955-907c-a2e6ab446f98.pdf"}],"financialInterests":"","formattedTitle":"Life Cycle Assessment of Micro-Activated Flux Tungsten Inert Gas Welding and Conventional Tungsten Inert Gas Welding: A Case Study","fulltext":[{"header":"1.\tIntroduction","content":"\u003cp\u003eWelding is the most common method used for joining two metals. Among the various welding processes, gas tungsten arc welding (GTAW), also known as conventional TIG (C-TIG) welding, is widely employed in industrial applications. C-TIG is classified as a fusion welding process, where an electric arc is generated to melt the base metal and a non-consumable tungsten electrode. The electric arc in welding releases energy in an ionized gas environment, generating sufficient heat to melt the base metal and form a weld pool. This pool is shielded from atmospheric contamination by inert gases, primarily argon or helium. Upon solidification, the weld bead is formed. The TIG process is highly versatile and finds extensive use in industries such as aerospace, construction, oil and gas, shipbuilding, and nuclear power [1, 2]. While C-TIG welding is celebrated for its precision and ability to produce high-quality welds, it has notable limitations, including limited weld penetration, high heat input, and low productivity, particularly when working with alloys of varying thicknesses [3, 4]. Additionally, achieving a desirable DOP in C-TIG requires edge preparation, a post-process step that is not necessary in A-TIG[5, 6]. To address these challenges, researchers have explored innovative approaches, such as ultrasonic vibration and activating fluxes composed of nano- and micro-sized metal oxide particles[7, 8]. These advancements aim to improve welding efficiency and mitigate the inherent limitations of conventional TIG methods. The flux-assisted method involves applying a thin layer of flux to the surface of the base metal before welding[9]. This technique significantly increases penetration depth, achieving 1.5 to 2.5 times greater depth compared to conventional TIG welding [10, 11]. Among the metal oxides used in A-TIG, TiO₂, and SiO₂ are reported to be the most effective fluxes. They help reduce weld bead width and significantly enhance weld penetration when used with GTAW [12]. The use of metal oxide fluxes is common in various other manufacturing methods[13, 14]. The welding industry, a vital segment of the metallurgical sector, has faced growing criticism in recent decades for its substantial consumption of raw materials. This has led to ecosystem degradation, loss of biodiversity, and pollution of water and soil. Sattarpanah et al. [15] used finite element analysis to evaluate the thermal behavior of TIG-welded stainless steels. Their study revealed a clear relationship between welding speed, bead width, and penetration depth. An increase in current and a decrease in welding speed result in both an increase in weld bead width and greater penetration depth. This occurs because the input energy, derived from the increased current, is higher, which in turn transfers more energy to the material, leading to a larger molten volume. In the USA, \u003cem\u003esustainable manufacturing\u003c/em\u003e was defined as the process of producing goods in ways that reduce environmental harm, conserve energy and resources, prioritize the safety of workers, communities, and consumers, and maintain economic viability\u0026nbsp;[16].\u0026nbsp;Sustainable development in manufacturing industries provides a means to not only minimize environmental impacts but also enhance economic and social performance\u0026nbsp;[17]. Grasping the essence of sustainable development hinges on recognizing the life-cycle concept as its most critical element[18]. The industrial sector stands as one of the most resource-intensive and polluting domains, contributing to over 40% of global energy consumption[19]. The economic importance of welding processes in Europe and their influence on the European industry have been significant for several years now. Numerous studies have examined the economic impact of welding processes and explored methods or tools to reduce costs\u0026nbsp;[20]. Additionally, approaches have been developed to assist in selecting the most cost-effective welding process based on economic factors.\u003c/p\u003e\n\u003cp\u003eThis study compares micro-sized A-TIG and C-TIG bead-on-plate welding in terms of key performance metrics and environmental considerations. The analysis also addresses the total production time, including preprocessing time for flux preparation, while evaluating the direct and indirect energy consumption associated with each method. These metrics form the foundation for a comparative assessment aimed at identifying resource-efficient and sustainable practices.\u003c/p\u003e\n\u003cp\u003eThe focus of the study is on energy consumption, ecological footprint, and overall sustainability. Both processes were evaluated from economic and environmental perspectives, with an ecological assessment based on critical factors such as electrical energy usage, shielding gases, and micro-sized metal oxide fluxes, considering their impacts on health, ecosystems, and resources. The analysis utilized the Ecoinvent 3 database within SimaPro 9.2. To our knowledge, no previous study has experimentally compared the LCA of these two welding methods. This research provides new insights into the environmental costs of each approach through a case study using SS304L, a widely applied base metal.\u003c/p\u003e"},{"header":"2.\tMethods","content":"\u003cp\u003eThis section details the methodology employed in the case study, emphasizing the defined scope of the LCA, the two distinct welding processes under evaluation, the criteria for ensuring comparable specimens, and the measurement techniques utilized.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.1.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eC-TIG and A-TIG Welding Experiments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe C-TIG technique employed in this research uses a non-consumable tungsten electrode to create an arc for welding, with Argon serving as an inert shielding gas to protect the weld pool from contamination. No filler material was used, and the welding process was applied to fabricate a 100-millimeter specimen. In the A-TIG process, a TiO₂ micro-size (30 microns) activating flux was applied to the workpiece surface prior to C-TIG welding. The flux improves heat input, resulting in deeper weld penetration, better control over the weld pool, and enhanced weld quality [21, 22]. This process allows for reduced heat input, which helps minimize distortion and improves the DOP. To prepare the flux, 1 gram of TiO₂ metal oxide was combined with 5 milligrams of methanol and stirred on a magnetic hot plate stirrer at a rotation speed of 600 RPM for 20 minutes in ambient air(20\u003csup\u003eo\u0026nbsp;\u003c/sup\u003eC). The flux was then applied to the base metal (SS304L) to a depth of 0.025 mm along the intended weld bead before bead-on-plate TIG welding.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA GamElectric PSQ250 AC/DC welding machine was used for the deposition process, featuring a single-axis motion system to regulate the welding speed, and a three-phase JAM 300 tariff meter was employed to measure the electricity consumption of the stirrer, as illustrated in Figure 1.\u003c/p\u003e\n\u003cp\u003eThis study aims to compare the LCA of specimens with nearly identical DOP achieved using A-TIG and C-TIG processes. Screening experiments based on prior studies were conducted for both methods to establish comparable welding parameters, ensuring almost identical DOP as the evaluation criterion. Specifically, a DOP of 1.7 mm was achieved with different welding currents: 170 A for C-TIG and 100 A for A-TIG, resulting in distinct environmental impacts. The ecological implications of micro-activated fluxes were assessed by evaluating the production of metal oxides in micro size, the energy consumption of the magnetic hot plate stirrer, and the methanol used in flux preparation. These analyses were informed by data obtained from laboratory experiments, numerical calculations, and the Ecoinvent 3 database. Table 1 provides a detailed presentation of the input parameters utilized in both welding methods, highlighting the distinctions in energy consumption, and process characteristics.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable.1. \u0026nbsp;C-TIG and A-TIG welding input parameters\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003eWelding method\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eParameters\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003eC-TIG\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 95px;\"\u003e\n \u003cp\u003eA-TIG\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eMicro flux\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 95px;\"\u003e\n \u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eCurrent (A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e170\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 95px;\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eGas Flow (L/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 95px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eShielding Gas (99.9% purity)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003eAr\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 95px;\"\u003e\n \u003cp\u003eAr\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eTravel Speed (cm/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e145\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 95px;\"\u003e\n \u003cp\u003e145\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eGap(mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 95px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eElectrode Diameter(mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e2.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 95px;\"\u003e\n \u003cp\u003e2.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eTorch Angle(Degree)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 95px;\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eGas Nozzle Diameter(mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 95px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eElectrode Tip Angle(Degree)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 95px;\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eFigure 2 provides an overview of the case study specimens analyzed. Figure 2(a) highlights the 100 mm bead-on-plate samples, illustrating the experimental setup. Magnified cross-sectional views of the welded samples in Figures 2(b) and 2(c) reveal the identical DOP achieved by the C-TIG and A-TIG welding processes, emphasizing their comparable weld penetration performance.\u003c/p\u003e\n\u003cp\u003e2.2 \u0026nbsp;\u003cstrong\u003eLife Cycle Assessment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLCA is an effective method for evaluating the environmental impact of a product, process, or service across its entire life cycle, from resource extraction to final disposal [23]. It helps manufacturers identify areas for improvement to make their processes more sustainable. LCA allows for the comparison of two systems delivering the same service or product, as defined by the functional unit (FU). It provides data on environmental footprints, such as carbon emissions, and supports the creation of environmental statements or eco-labeling to promote sustainable practices. Based on the ISO 14040 standard LCA has four stages [24]. The first one is called Goal and Scope Definition; it defines the purpose and the system boundary of the assessment. The second is the Inventory Analysis, Life Cycle Inventory (LCI), which involves data collection on all inputs and outputs throughout each stage of the life cycle. These data create the basis for assessing the impact. The third step involves the life cycle Impact Assessment (LCIA), which changes the collected data into quantifiable environmental impact categories, such as GWP. The last stage is the Interpretation, analysis, and evaluation of results concerning the stated goals, such as recommendations and identification of hotspots [25]. The environmental analysis section of this study assesses the lifecycle impacts of specimens produced using C-TIG and A-TIG welding techniques. It outlines the scope and objectives, describes the Life Cycle Inventory (LCI), and conducts a comprehensive LCA. The FU for the comparison comprises two stainless steel SS304L components, each measuring 100 \u0026times; 50 \u0026times; 5 mm, welded using both methods to achieve a uniform Depth of Penetration (DOP) of 1.75 mm. The LCA evaluates the environmental performance of these welding processes for a 100 mm weld length, as illustrated in Figure 2(a). This assessment provides a clear basis for comparing the environmental impacts of the two methods in achieving identical welding outcomes. Figure 3\u003cspan dir=\"RTL\"\u003e.\u003c/span\u003e depicts the system boundaries defined for the LCA, encompassing the entire life cycle from raw material processing to the final part.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eData collection includes calculating the primary process energy and auxiliary energy for equipment using direct and indirect methods, such as machine tags or kWh meters. Supplementary data were sourced from the Ecoinvent 3 database, ensuring that the selected data reflect the study\u0026apos;s location in Iran. A systematic approach was employed to calculate the energy consumption during the welding processes of A-TIG and C-TIG. The energy consumption was determined using Equation 1, which accounts for the efficiency of the welding machine. This equation \u0026nbsp; represents the effective energy consumption in Watt-hours (Wh), the voltage in volts, the current in amperes, the welding duration in hours, and the welding machine efficiency, assumed to be 85%. This approach ensured an accurate representation of energy inputs during the welding phase.\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"606\" height=\"51\"\u003e\u003c/p\u003e\n\u003cp\u003eIn the C-TIG process, the voltage was 16.7 V and the current was 170 A, while in the A-TIG process, the voltage was 13.9 V and the current was 100 A. With the travel speed assumed to be constant, resulting in a welding time of 4.13 seconds, and an efficiency factor of 0.85, the energy consumption was calculated using Equation 1. The results showed that the welding energy consumption for C-TIG was 2304.6 Wh, while for A-TIG it was 1128.4 Wh. In both welding methods, the shielding gas used to protect the weld pool was measured using a flowmeter, as the gas flow rate is a critical input variable in the welding process. A flow rate of 10 liters per minute was selected based on a review of relevant literature. To calculate the shielding gas usage, the flow rate was multiplied by the welding time to determine the volume of gas used, which was then converted to mass by multiplying it by the density of Argon (0.001784 kg/L). This calculation resulted in approximately 0.00123 kg of Argon used per weld. The environmental impact of the shielding gas was reported separately for each welding method to ensure a comprehensive assessment of energy inputs. The data collected for the LCI was standardized to an FU of a 100-millimeter welded sample for both methods, facilitating a consistent comparison of environmental impacts. Table 2 provides a summary of energy consumption for welding the samples. In the C-TIG process, the energy consumption includes the entire hot rolling process, which encompasses billet rolling for base metal production. Conversely, the A-TIG process accounts for an additional stage of flux preparation, with the required electricity measured using a three-phase JAM 300 tariff meter. The quantities of methanol and metal oxide used were determined from published studies, weighed, and their environmental impacts evaluated using the database.\u003c/p\u003e\n\u003cp\u003eTable 2. LCI for C-TIG and A-TIG fabricated \u0026nbsp;specimen\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"639\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eProcess\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 222px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eC-TIG\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 238px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eA-TIG\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003eAmount\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003eUnit\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 99px;\"\u003e\n \u003cp\u003eType of Data\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003eAmount\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003eUnit\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003eType of Data\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHot Rolling\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e0.196\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003ekg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 99px;\"\u003e\n \u003cp\u003eEcoinvent 3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e0.196\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003ekg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003eEcoinvent 3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eArc welding \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e0.23035\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003ekWh\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 99px;\"\u003e\n \u003cp\u003eCalculated\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e0.11282\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003ekWh\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003eCalculated\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eShielding Gas(Argon)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e0.00123\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003ekg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 99px;\"\u003e\n \u003cp\u003eMeasured-Ecoinvent 3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e0.00123\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003ekg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003eMeasured-Ecoinvent 3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMicro-size TiO\u003csub\u003e2\u003c/sub\u003e\u0026nbsp; powder\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 99px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003ekg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003eEcoinvent 3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWater\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 99px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e0.0015\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003eM\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003eEcoinvent 3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMethanol\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 99px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e3.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003eg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003eEcoinvent 3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eElectricity \u0026nbsp; (flux stirrer)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 99px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003ekWh\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003eMeasured\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eTo conduct an LCA of the environmental impacts associated with the manufacturing process, multiple impact categories are analyzed. More details on these categories are provided in the results and discussion section. These indicators align with the EPD2018 methodology, ensuring a comprehensive evaluation of environmental performance [26]. Of the databases available, Ecoinvent3-allocation, cut-off by classification library, and EPD2018 and \u0026nbsp;ReCiPe 2016 Midpoint(H) methods were applied, as part of the standard LCA process. The impact categories of the EPD 2018 methodology are shown in Table 3.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 3. Impact indicators of EPD 2018 for A-TIG and C-TIG\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003eImpact Category\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 134px;\"\u003e\n \u003cp\u003eUnit\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003eA-TIG\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 88px;\"\u003e\n \u003cp\u003eC-TIG\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003eAcidification(fate not included)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 134px;\"\u003e\n \u003cp\u003ekg SO\u003csub\u003e2\u003c/sub\u003e eq.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e0.000775\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 88px;\"\u003e\n \u003cp\u003e0.000993\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003eEutrophication\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 134px;\"\u003e\n \u003cp\u003ekg PO\u003csub\u003e4\u003c/sub\u003e---- eq.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e0.000151\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 88px;\"\u003e\n \u003cp\u003e0.000176\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003eGlobal Warming(GWP 100a)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 134px;\"\u003e\n \u003cp\u003ekg CO\u003csub\u003e2\u003c/sub\u003e eq.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e0.195\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 88px;\"\u003e\n \u003cp\u003e0.242\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003ePhotochemical oxidation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 134px;\"\u003e\n \u003cp\u003ekg NMVOC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e0.00155\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 88px;\"\u003e\n \u003cp\u003e0.000745\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003eAbiotic depletion, elements\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 134px;\"\u003e\n \u003cp\u003ekg Sb eq.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e5.32E-7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 88px;\"\u003e\n \u003cp\u003e9.43E-7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003eAbiotic depletion, fossil fuels\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 134px;\"\u003e\n \u003cp\u003eMJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e2.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 88px;\"\u003e\n \u003cp\u003e3.45\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003eWater scarcity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 134px;\"\u003e\n \u003cp\u003eM\u003csup\u003e3\u003c/sup\u003e eq.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e0.278\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 88px;\"\u003e\n \u003cp\u003e0.181\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003eOzone layer depletion(ODP)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 134px;\"\u003e\n \u003cp\u003ekg CFC-11 eq.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e2.08E-8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 88px;\"\u003e\n \u003cp\u003e2.56E-8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"},{"header":"Results and Discussion","content":"\u003cp\u003eThe results of the case study, obtained from the LCA and using the EPD2018 impact categories, are illustrated in Figure 4. The analysis is based on the 100 mm welded FU and the data from the LCI for both A-TIG and C-TIG processes. The environmental impacts of the C-TIG and A-TIG welding methods were analyzed, revealing notable distinctions due to differences in process inputs and energy requirements. A-TIG employed a TiO₂ activating flux, which enhanced process efficiency by improving heat input and weld penetration. C-TIG process demonstrated higher impacts across all the categories of acidification, eutrophication, global warming, photochemical oxidation, abiotic depletion of elements, abiotic depletion of fossil fuels, Water scarcity, and ozone layer depletion. These differences are attributed to the additional energy required for the C-TIG process, as its current level is 70% higher than that of A-TIG.\u003c/p\u003e\n\u003cp\u003eAs illustrated in Figure 4, the C-TIG process exhibited higher impacts across most categories, with C-TIG impact in acidification potential, which was 17% greater than that of A-TIG equivalent to 0.000158 kg SO\u003csub\u003e2\u003c/sub\u003e. Acidification potential, measured in SO₂ equivalents, highlights the environmental burden of emitted sulfur and nitrogen compounds, which react in the atmosphere to form sulfuric and nitric acids [27]. These acids contribute to soil and water pollution through acid rain, which depletes soil nutrients, harms plant and animal life, and disrupts ecosystems [9]. The higher acidification potential of C-TIG underscores its energy-intensive nature and its greater environmental impact compared to A-TIG. Eutrophication impacts were observed to be 14.5% higher in C-TIG, likely resulting from the increased energy consumption associated with this welding process. Eutrophication occurs when excess nutrients, particularly nitrogen and phosphorus compounds, enter water bodies or soil systems, leading to several environmental issues, such as excessive algae growth that blocks sunlight and disrupts aquatic ecosystems, reduced oxygen levels in water due to the decomposition of organic matter, fish mortality, and overall ecosystem changes, including reduced biodiversity and habitat degradation [28]. The higher energy usage in C-TIG, especially when powered by fossil fuel-based electricity grids, contributes to nutrient enrichment in water bodies. This is primarily due to the release of nitrogen oxides (NOx) and sulfur oxides (SOx) during fuel combustion, which can be deposited into water systems through atmospheric processes and rainwater. The GWP measures the extent to which various greenhouse gases contribute to atmospheric warming over a specific time, typically 100 years, relative to CO₂, which serves as the reference gas with a GWP of gases like methane (CH₄), nitrous oxide (N₂O), and chlorofluorocarbons (CFCs) have significantly higher GWPs due to their greater heat-trapping capacities and atmospheric lifespans. This metric facilitates standardized comparisons of greenhouse gases, enabling the assessment of their relative impacts on climate change[29]. In carbon footprint analysis and emissions reporting, GWP converts the warming effects of all greenhouse gas emissions into CO₂ equivalents. For instance, the C-TIG process exhibits a 19.4% higher GWP than A-TIG, mainly due to its energy-intensive nature, where the welding current requirement is 1.7 times greater in the case study. This increased energy demand, particularly in fossil fuel-reliant regions like Iran, results in higher CO₂ emissions from fuel combustion. Additionally, natural gas extraction and distribution processes often lead to methane leaks, which have a GWP 28\u0026ndash;36 times that of CO₂ over 100 years. The compounded effect of increased energy consumption and methane emissions substantially elevates the GWP of processes like C-TIG, highlighting the environmental cost of inefficiencies in energy use. Among the environmental categories, ADE in the C-TIG process showed the largest difference, with an increase of 43.6%, corresponding to an additional 4.11E-7 Sb-equivalent per FU. ADE measures the reduction of non-renewable mineral resources, such as metals and rare elements, due to human activities like mining and industrial processes [30]. This depletion is especially significant in energy generation, where the extraction and processing of raw materials, including fossil fuels for power plants, contribute substantially to ADE. The extraction of natural gas\u0026mdash;a major source of power in Iran\u0026mdash;involves resource-intensive processes, including the mining of metals such as steel, aluminum, and copper. These materials are essential for the infrastructure used in gas extraction, transport, and electricity generation. As these metals are mined, non-renewable elements are depleted, thus contributing directly to ADE. In the case of the C-TIG welding process, the higher energy consumption amplifies the ADE impact. This process relies heavily on electricity, which in regions like Iran, where natural gas is the predominant energy source, is largely generated from natural gas combustion. Consequently, the increased energy demand for C-TIG further accelerates the extraction of natural gas, leading to higher ADE values associated with the welding process. The observed 17.9% higher impact in ADF for the C-TIG process can primarily be attributed to its higher energy consumption compared to A-TIG. The C-TIG process, which requires more electricity for its welding operations, leads to a greater demand for energy production. In regions like Iran, where electricity is largely generated through natural gas combustion, this results in increased extraction and consumption of fossil fuels, particularly natural gas, which is a key contributor to ADF[31]. The increased energy demand for the C-TIG process means more fossil fuels are burned to produce the required electricity, thus leading to higher fossil fuel depletion. This impact is directly correlated to the energy-intensive nature of the C-TIG process, where more energy per unit of welding is consumed. Additionally, since natural gas extraction and combustion are resource-heavy activities, they deplete non-renewable fossil fuel reserves at a higher rate. Infrastructure for gas extraction, such as drilling rigs and pipelines, requires metals and other resources that also contribute to fossil fuel depletion. Therefore, the C-TIG\u0026apos;s energy dependence exacerbates the depletion of fossil fuels, making it more impactful than the A-TIG process in terms of ADF. The higher ozone depletion impact of 18.7% in the C-TIG process was primarily attributed to emissions from fossil fuel-based energy generation. This process can release trace substances or generate indirect emissions that contribute to ozone layer depletion, although these effects are minor compared to those caused by industrial refrigerants or solvents [32]. The observed difference is more likely a result of the increased energy consumption in C-TIG, which intensifies emissions associated with electricity generation in regions reliant on fossil fuels.\u003c/p\u003e\n\u003cp\u003eConversely, A-TIG, a promising alternative to conventional methods, exhibits higher ecological impacts in only two categories: photochemical oxidation and water scarcity. This highlights its potential for broader environmental benefits while identifying specific areas where further optimization is needed to enhance its sustainability profile. Titanium dioxide (TiO\u003csub\u003e2\u003c/sub\u003e) occurs naturally in various crystalline forms, with rutile being the most common. In Iran, the sulfate process is a common method for TiO\u003csub\u003e2\u003c/sub\u003e production. The typical particle size of produced TiO\u003csub\u003e2\u003c/sub\u003e in Iran varies but often falls within the sub-micron to several micron range. To achieve a particle size of 30 microns, techniques like grinding (e.g., ball milling, jet milling) and classification (e.g., sieving, air classification) can be employed. However, careful consideration must be given to factors such as particle size distribution, product quality, and economic feasibility when selecting and implementing these methods [33]. Photochemical oxidation, also known as ozone creation potential, refers to the formation of ground-level ozone (tropospheric ozone) through chemical reactions involving nitrogen oxides (NOx) and volatile organic compounds (VOCs) under ultraviolet (UV) radiation. This process is a key contributor to summer smog, a type of air pollution that can adversely affect human respiratory health, damage vegetation, and reduce agricultural productivity [34]. The impact of photochemical oxidation was found to be 52% higher in A-TIG compared to C-TIG, highlighting the environmental challenges associated with the additional flux preparation in A-TIG. The emission of methanol used in the process and the extra energy consumption required for metal oxide and solvent preparation contribute significantly to this impact. Furthermore, A-TIG\u0026apos;s reliance on fossil fuel-based energy for flux preparation leads to increased NOx and VOC emissions during electricity generation and related industrial activities. These emissions intensify the formation of photochemical smog, exacerbating air quality issues and contributing to environmental degradation. The 35.1% higher impact of A-TIG on water scarcity highlights the significant role of water usage in its production processes [35]. This disparity is primarily attributed to the water-intensive activities involved in the extraction and processing of ilmenite, as well as the preparation of TiO₂ micro-powder used as flux. The mining and beneficiation of ilmenite require substantial water resources for ore washing and separation. Additionally, the chemical treatments and refinement processes for TiO₂ production consume considerable amounts of water, contributing further to this impact. These findings emphasize the need for improved water management and resource optimization in the production and application of TiO₂-based flux materials to reduce their environmental footprint. While A-TIG delivers superior weld quality and efficiency, its overall environmental footprint is comparatively lower. In contrast, C-TIG\u0026apos;s energy-intensive operation results in significantly higher environmental impacts across most of the evaluated categories. This underscores the importance of considering both performance and sustainability when selecting welding methods.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eUsing the ReCiPe 2016 methodology, the results of this study are simplified into endpoint categories to enhance clarity and facilitate communication of environmental impacts. Endpoint modeling translates complex environmental effects into measurable damage across three primary areas: human health, ecosystems, and resources. The Human Health category reflects the potential impact of environmental burdens on human well-being, such as the increase in disease or mortality rates due to air pollution, toxic emissions, and greenhouse gases. In this study, human health damage is influenced heavily by emissions from energy-intensive processes, particularly in the C-TIG method. Ecosystems evaluate the harm to biodiversity and natural habitats caused by environmental degradation, such as land use, pollution, and climate change. Ecosystem damage from the processes arises primarily from emissions that contribute to acidification, eutrophication, and habitat disruption. Resources quantify the depletion of non-renewable resources, including fossil fuels and critical minerals, which are consumed during energy production and material extraction. Resource depletion is more pronounced in energy-intensive processes like C-TIG, which rely on fossil fuel-based electricity generation. Figure 5 illustrates the environmental performance of A-TIG and C-TIG across these three endpoint indicators. By condensing the impacts into these categories, this approach provides a comparative framework that aids in understanding the trade-offs in sustainability between the two processes. It underscores the need to balance operational efficiency with environmental responsibility.\u003c/p\u003e\n\u003cp\u003eThe environmental impact assessment of A-TIG and C-TIG processes provides valuable insights when considering normalization results. The normalization results are presented in Figure 6, emphasizing the dominance of the human health category. The normalized values for human health reach 14.955 for A-TIG and 24.1788 for C-TIG, significantly higher than the values for ecosystems and resources, which remain below 5.0E-06 for both processes. This indicates that the human health impacts are greater in order of magnitude than in the other categories. The slightly higher value for C-TIG in the ecosystems category reflects increased emissions or energy use during the process. Meanwhile, the minimal contributions to ecosystems and resources confirm the relatively low environmental burden in these categories. Figure 6 presents the environmental impact assessment of the A-TIG welding process using the EPD 2018 methodology. The analysis reveals that, while the A-TIG process has a lower overall environmental burden compared to alternative methods, it exhibits significant impacts in specific categories due to additional pre-processing steps, such as flux usage. Natural gas combustion, primarily used for welding energy consumption, emerges as a major contributor to environmental impacts. It accounts for 83.9% of the impact in Abiotic Depletion of Elements, 47.8% in Ozone Layer Depletion, 46.4% in GWP and Abiotic Depletion of Fossil Fuels, 46.1% in Acidification, 37.1% in Eutrophication, 15.3% in Photochemical Oxidation, and 3.23% in Water Scarcity. These impacts are driven by the energy-intensive nature of the process, particularly during flux preparation and application, where natural gas plays a critical role. The TiO₂ micro-powder used as an activating flux in A-TIG welding significantly impacts acidification (22.6%) and eutrophication, GWP, and ADF (18.1%\u0026ndash;19.1%). These impacts result from the energy-intensive processes of titanium dioxide production, which include mining, extraction, and refining of raw materials. Emissions of nitrogen and sulfur compounds during these operations contribute to acidification by forming acidic substances in the atmosphere. Similarly, wastewater and nutrient runoff from TiO₂ production contribute to eutrophication, leading to issues like algae blooms and oxygen depletion in aquatic ecosystems. Methanol, employed in flux preparation, is the largest contributor to photochemical oxidation, accounting for 60% of the impact in this category. Methanol\u0026apos;s environmental footprint arises from its production, which depends on fossil fuel-derived feedstocks, and its emissions during usage, which include volatile organic compounds with ozone-depleting potential. Overall, the environmental impacts of A-TIG welding are significantly influenced by the materials and energy required for flux preparation and application. These findings underscore the importance of optimizing flux formulations and improving energy efficiency in the process to mitigate associated environmental burdens.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe comparative environmental assessment of A-TIG and C-TIG welding processes underscores the trade-offs between efficiency and sustainability. A-TIG demonstrates superior energy efficiency and lower overall environmental impacts; however, its dependence on TiO₂ flux results in notable burdens in specific categories such as photochemical oxidation and water scarcity. In contrast, C-TIG consistently exhibits higher environmental impacts across most evaluated categories, primarily due to its energy-intensive nature, requiring 70% more electricity than A-TIG.\u003c/p\u003e\n\u003cp\u003eKey findings include:\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003eAcidification potential: C-TIG Impact is 17% higher than A-TIG, equivalent to an additional equivalent to 0.000158 kg SO\u003csub\u003e2\u003c/sub\u003e/FU. These acids contribute to soil and water pollution through acid rain, which depletes soil nutrients, harms plant and animal life, and disrupts ecosystems\u003c/li\u003e\n \u003cli\u003eEutrophication impacts: C-TIG Impact is 14.5% higher than A-TIG. Resulting from the increased energy consumption associated with this welding process\u003c/li\u003e\n \u003cli\u003eGWP: C-TIG Impact: 19.4% higher, reflecting greater CO₂ and methane emissions from fossil fuel-based electricity. Methane, with a GWP 28\u0026ndash;36 times higher than CO₂ over 100 years, intensifies the effect. Enhanced greenhouse gas emissions exacerbate climate change risks.\u003c/li\u003e\n \u003cli\u003eADE: C-TIG Impact: 43.6% higher than A-TIG, equivalent to an additional 4.11E-7 Sb-equivalent per FU. The energy-intensive nature of C-TIG is linked to the extraction and processing of natural gas and the use of metals like steel, copper, and aluminum in infrastructure.\u003c/li\u003e\n \u003cli\u003eADF: C-TIG Impact: 17.9% higher than A-TIG. Increased electricity demand (70% higher in C-TIG) results in more natural gas combustion, directly contributing to fossil fuel depletion.\u003c/li\u003e\n \u003cli\u003eOzone Layer Depletion in C-TIG is 18.7% higher, primarily linked to fossil fuel-based energy generation.\u003c/li\u003e\n \u003cli\u003eA-TIG\u0026apos;s photochemical oxidation impact is 52% higher than C-TIG, driven by methanol emissions, energy-intensive flux preparation, and fossil fuel reliance. These factors increase NOx and VOC emissions, contributing to ground-level ozone formation, which harms air quality, respiratory health, and agricultural productivity.\u003c/li\u003e\n \u003cli\u003eThe 35.1% higher impact of A-TIG on water scarcity is likely attributed to the water usage involved in the extraction of ilmenite and the preparation of TiO₂ micro-powder for flux production.\u003c/li\u003e\n \u003cli\u003eHuman Health: Normalized values of 14.955 (A-TIG) vs 24.1788 (C-TIG), dominated by emissions from energy-intensive operations in C-TIG.\u003c/li\u003e\n \u003cli\u003eEcosystems and Resources: Normalized values remain below 5 for both processes. Lower impacts highlight minimal burdens relative to human health.\u003c/li\u003e\n \u003cli\u003eThe environmental impacts of A-TIG welding are significantly influenced by natural gas combustion and the energy-intensive preparation of TiO₂ micro-powder and methanol-based flux. Natural gas contributes substantially to impacts such as abiotic depletion, GWP, and acidification, while TiO₂ production drives acidification and eutrophication through emissions and wastewater. Methanol accounts for 60% of photochemical oxidation impacts due to its fossil fuel-derived production and volatile emissions\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate and publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was conducted in accordance with the ethical guidelines outlined by the Committee on Publication Ethics (COPE). All participants provided written informed consent to participate in the study\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors made substantial contributions to this research work. Mahdi Mazloom Farsibaf, the first author, led the material preparation, data collection, formal analysis, and methodology. He also drafted the initial version and revised the final manuscript. \u0026nbsp;Abolfazl Moradian contributed significantly to the experimental design and assisted in data analysis and interpretation of the results. Dr, Amirmohammad Ghandehariun provided technical support during the experimental phase and contributed to refining the methodology. Dr Farhad Kolahan, the corresponding author, supervised the entire project, offered critical insights throughout the research, and thoroughly reviewed and revised the manuscript for important intellectual content. All authors engaged in critically revising the manuscript, provided valuable feedback on multiple drafts, and approved the final version for publication\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funding was obtained for this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of conflicting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors did not receive support from any organization for the submitted work\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eKumar, K., et al., \u003cem\u003eA review on TIG welding technology variants and its effect on weld geometry.\u003c/em\u003e Materials Today: Proceedings, 2022. \u003cstrong\u003e50\u003c/strong\u003e: p. 999-1004.\u003c/li\u003e\n\u003cli\u003eChauhan, R., et al., \u003cem\u003eEffect of Various Fluxes on Different Metals and Alloys in A-TIG Process: A Review.\u003c/em\u003e Jurnal Kejuruteraan, 2022. \u003cstrong\u003e34\u003c/strong\u003e(4): p. 543-553.\u003c/li\u003e\n\u003cli\u003eVarshney, D. and K. 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Resources, 2021. \u003cstrong\u003e10\u003c/strong\u003e, DOI: 10.3390/resources10120120.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Life cycle assessment(LCA), welding, A-TIG, C-TIG, energy consumption","lastPublishedDoi":"10.21203/rs.3.rs-5987969/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5987969/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWelding methods and equipment have evolved over the years with advancements in human lifestyles and environmental needs. Among these, Conventional Gas Tungsten Inert Gas (C-TIG) Welding stands out because of its specialized applications and is recognized for its importance in manufacturing. However, the low depth of penetration (DOP) in thick sheet metals has necessitated the development of assisted methods, such as activating fluxes in the Activated TIG (A-TIG) process. This study conducts a comparative sustainability analysis of A-TIG and C-TIG welding processes. A-TIG utilizes a TiO₂-based flux to enhance weld penetration. A Life Cycle Assessment (LCA) was performed using the Ecoinvent 3 database and EPD 2018 and ReCiPe 2016 Endpoint (H) methodologies. Results indicate that A-TIG exhibits higher impacts in photochemical oxidation and water scarcity due to TiO₂ flux preparation and methanol usage. C-TIG shows higher impacts in acidification, eutrophication, global warming potential (GWP), abiotic depletion of elements (ADE), abiotic depletion of fossil fuels (ADF), and ozone layer depletion because its energy-intensive nature requires 70% more electricity. Endpoint modeling identifies human health as the most affected category, with C-TIG contributing 62% more damage due to emissions and energy use. Despite A-TIG\u0026rsquo;s improved energy efficiency and weld quality, its flux reliance introduces specific environmental trade-offs. This research highlights the need to balance weld quality and ecological sustainability for greener manufacturing practices.\u003c/p\u003e","manuscriptTitle":"Life Cycle Assessment of Micro-Activated Flux Tungsten Inert Gas Welding and Conventional Tungsten Inert Gas Welding: A Case Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-21 11:14:24","doi":"10.21203/rs.3.rs-5987969/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"de880ece-badc-48a3-8f4b-be2ae64d2c79","owner":[],"postedDate":"April 21st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-05-14T14:33:43+00:00","versionOfRecord":[],"versionCreatedAt":"2025-04-21 11:14:24","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5987969","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5987969","identity":"rs-5987969","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}