201不锈钢点焊工艺优化与焊点质量分析

Optimization design of pot welding process and the analysis of the welding quality for 201 stainless steel

针对电阻点焊过程非线性、多变量耦合和存在随机不确定因素的特点,采用正交试验设计方法科学安排点焊试验,研究电极压力、焊接电流和焊接时间对201不锈钢点焊接头拉剪强度及焊点熔核直径间的关系。研究结果表明,焊接电流对焊点质量影响最大,电极压力次之,焊接时间的影响最小。试验范围内的最佳焊接规范参数为:焊接电流6.4 kA、电极压力3.6 kN、焊接时间8周波,点焊接头拉剪强度可达8.92kN。201不锈钢点焊接头中的主要焊接缺陷为缩孔和结晶裂纹,采用较大的电极压力和较小的焊接电流焊接可减少焊接缺陷的形成,使接头承载能力明显提高。

The resistance spot welding is a process of nonlinear,multivariable coupling and the presence of the characteristics of random uncertainty.Orthogonal design and mathematical method have been used to plan the experiment in this paper,The effects of wehting parameters on the tensile shear strength and the nugget diameter have been studied thruugh a series of experiments investigations for 201 stainless steel.The results show that welding current has significant effect on welding quality,then electrode force and welding time.The optimum parameters are as follows：electrode force is 3.6 kN,welding current is 6.4 kA and welding time is 8 cycles.＇Fhe maximum tensile shear force is up to 8.92 kN.The microstructure of spot weld is cohmmar crystals in the nugget and eqniaxed grains around periphery induced by non-equilibrium freezing.And the typical spot welding defect of 201 stainless steel are shrinkage cavity and solidification crack ,joint qt,ality can he improved by using higher electrode force and smaller welding current.