Comparative study on the behavior of keyhole in analogy welding and real deep penetration laser welding

In deep penetration laser welding, the behavior of keyhole has an important influence on the welding quality. As it is difficult to directly observe the keyhole during metal laser welding, theoretical analysis and numerical simulation methods are common-used methods in studying the keyhole behavior, which cannot provide the direct real information of the keyhole behavior. In this paper, a method of analogy welding is proposed, in which high speed gas is used to blow the liquid to generate keyhole. Relevant process experiments are conducted to explore the keyhole behavior in the analogy welding and real deep penetration laser welding. The pressure balance of keyhole both in analogy welding and real deep penetration laser welding are analyzed. The laws obtained in analogy welding and real deep penetration laser welding are similar, which indicates that studying the keyhole formation and maintenance principle using the analogy welding method proposed in this paper may be helpful to deeply understand the keyhole formation and maintenance mechanism in real deep penetration laser welding.