直流电阻对焊接口张开及纵向裂纹的形成机制

The Mechanism of the Interface Split in the Flash and the Longitudinal Crack on the Joint Surface in DC Upset Butt Welding

采用有限元方法对板料直流电阻对焊过程中的接口张开、接头表面纵向裂纹问题进行了研究 .分析表明 ,焊接过程中金属的塑性流动导致界面质点力学状态发生动态变化 ,包括应力大小和拉压应力状态的变化 .变形过程中 ,界面质点在x轴方向所受的拉应力是接头内部产生层状撕裂的力学原因 ,在 y轴方向和z轴方向所受拉应力是产生接口张开和形成飞边纵向裂纹的力学原因 .

The butt joint interface split in the flash and longitudinal crack on the joint surface appeared in the process of D.C. upset butt welding have been studied by using the element method. The results show that the metal's plastic flow causes the variance of the stress status, including the value of the stress and the variance of the stress status from the stretch stress to the compress stress. In the process of D.C. upset butt welding, the stretch stress in x direction causes the layer avulsion, the stretch stress in y direction causes the butt joint interface split in the flash and the stretch stress in z direction causes longitudinal cracks on the joint surface.