薄板不锈钢旁路分流双面电弧高速焊接工艺分析

针对薄板不锈钢传统焊接方法焊接效率低、焊接缺陷多等问题，提出一种薄板不锈钢旁路分流双面电弧高速焊接方法。采用正面MIG-TIG背面TIG的双面焊接工艺，对船用2 mm厚的304不锈钢板进行焊接工艺机理研究。针对焊接效率提升问题，进行试验验证，对焊接过程中不同焊接速度和旁路电流对焊接质量的影响进行对比分析，并进行宏观组织和微观组织观察，通过拉伸试验验证焊缝接头力学性能的可靠性。结果表明，在施加旁路的情况下，正面旁路有效减小了母材的热输入，提升了焊接效率，并使焊缝热影响区组织得到较好的控制，达到细化晶粒的效果，从而减少焊缝咬边、塌陷等缺陷。创新点：(1)提出旁路分流双面电弧焊接工艺方法，对焊接过程中的热输入进行有效控制。(2)不锈钢薄板对接焊丝熔覆效率得到大幅度提升，有效解决焊接过程填丝效率低的问题。(3)焊接过程中焊缝热影响区组织和性能得到较好的控制。

Research on high speed welding of stainless steel by bypass current double-sided arc welding

Aiming at the problems of low welding efficiency and welding defects by traditional welding methods of stainless steel.The high-speed welding method of bypass current double-sided arc welding was proposed.The 2 mm thick 304 stainless steel plate was studied by using the double-sided arc welding process which is composed with MIG-TIG on the front and TIG on the back.According to welding efficiency problem, it is carried out welding efficiency improvement test verification.This thesis compares and analyzes the influence of respectively from macrostructure and microstructure of weld is analyzed.The weld tensile test can verify the reliability of the mechanical properties.The results show that when the bypass current is applied, the front bypass can effectively reduce the heat input of the base metal, improving the welding efficiency and controlling the microstructure of the weld heat affected zone well, so as to achieve the effect of grain refinement.It can reduce the weld edge bite, collapse and other defects. Highlights:(1)Double-sided arc welding with bypass current is proposed to effectively control the heat input. (2)The wire cladding efficiency of stainless steel sheet butt welding has been greatly improved, It can effectively solve the problem of lower wire filling efficiency in the welding process. (3)The microstructure and properties of the heated-affected zone are well controlled.