Penetration mechanism of aluminum alloy in double-sided GTAW process
(1.黑龙江省哈尔滨市哈尔滨工业大学现代焊接生产技术国家重点实验室2.State Key Laboratory of Advanced Welding Production Technology,Harbin Institute of Technology, Harbin 150001, China3.Department of Materials Engineering, Dalian University of Technology, Dalian 116024, China)
Abstract: The penetration mechanism of aluminum alloy in double-sided gas tungsten arc welding (GTAW) process was probed by means of theoretical analysis, experimentation and numerical simulation. The results show that, firstly, the welding current goes straight through the weld zone, forms a stronger electromagnetic force field, and causes a stronger fluid flow in the weld pool. Secondly, during double-sided GTAW process, when the weld is partial penetrated, a heat-congregated zone forms between the bottoms of the two weld pools, where the temperature can increase quickly even though only a small amount of heat is input. Thirdly, the buoyancy force causes an inward flow in the bottom weld pool, which can drive the hot liquid on the surface to the bottom of the pool.
Key words: aluminum alloy； double-sided GTAW process； weld penetration； numerical simulation