High frequency hybrid twin-electrode TIG welding process for stainless steel

In order to solve the problems of small arc pressure and depth of weld in twin-electrode TIG welding, a new type gas tungsten arc welding process of high frequency hybrid twin-electrode TIG welding (HFHT-TIG) was put forward. A high frequency pulse current was added on one tungsten electrode of twin-electrode TIG welding to achieve the purpose of improving the arc pressure and stiffness, stirring the molten pool, refining the grains, improving the microstructure and mechanical properties of the joint. The 6 mm thick austenitic stainless steel welding process test was carried out by HFHT-TIG welding and compared with twin-electrode TIG welding. The results show that HFHT-TIG could significantly increase the arc stiffness and pressure. The surface forming and cross-section symmetry of the weld was better. The microstructure of the weld was tinier. The dimples in the fracture were more uniform and fine. The joint tensile strength and break elongation increased by 12.1% and 30.2%, respectively.