Invar alloy is widely used in the manufacture of large-scale aircraft composite molds and LNG ships due to its extremely low coefficient of thermal expansion. It has broad application prospects. The key to the wide application of Invar alloy are the quality of the weld and the matching of the thermal expansion coefficient between the weld and the base metal. This article mainly introduces the most widely used traditional welding methods of Invar alloy

MIG and TIG

and the new welding methods including laser welding

laser arc hybrid welding and friction stir welding. Meanwhile

this paper summarizes the welding status of Invar alloy

and proposes a new high-quality

high-efficiency welding method: K–TIG welding.