不同工艺下超强钢点焊残余应力的试验分析

Analysis of test about residual stress of super steel spot welding under different process

关键词:  电阻点焊  残余应力  电极直径  焊接电流  锻压力

Key words:  resistance spot welding  residual stress  electrode diameter  welding current  forging pressure

摘要:

为了分析在不同工艺下电阻点焊对超强钢焊接构件内部残余应力的影响，文中试验选用B1500HS快冷淬火后的超高强钢薄板，通过德国NIMAK点焊机器人进行电阻点焊，制备焊接构件，并通过X射线衍射法测量点焊构件焊核区、热影响区、母材区表面处的残余应力，分别从电极直径、焊接电流、锻压力方面考察不同工艺对超强钢点焊构件残余应力的影响. 结果表明，残余应力以焊核为中心基本呈对称分布，从焊核到母材，数值先增大后减小，在热影响区处达到最大值且为拉应力，远离焊核区降低为压应力，且拉应力最大值明显高于压应力最大值；残余应力随电极直径增大而增大；残余应力随着电流增大其最大值先增大后减小；锻压力可以降低残余应力峰值.

Abstract:

In order to analyze the effect on resistance spot welding residual stress of super steel under different process, the B1500HS steel sheet which is after the quenching process of the fast cooling is choosed as the material in this experiment. The resistance spot welding component is conducted by German spot welding robot NIMAK. The X-ray diffraction method is used to measure the components residual stress of weld nugget, heat affected zone and parent metal area. The results showing that the residual stress is distributing symmetrically around the welding core and the value of residual stress increases first then decreases from welding core to the parent metal. Besides, the residual stress reaches its maximum value in the heat affected zone and characterized by tensile stress, then it reduced to be pressure stress away from the welding core, meanwhile the maximum tensile stress significantly powerful than the maximum pressure stress. The electrode diameter can increase the residual stress with the increase of welding current the residual stress increasise first than decrease. The forging pressure can effectively reduces the value of residual stress.