车辆焊接裂纹失效分析试验

Research on failure analysis of vehicle welding

针对货车车辆铁素体不锈钢和09Cu PCr Ni-A耐候钢焊接过程中出现的横向及纵向裂纹,通过对比分析焊材和母材的成分、观察裂纹的宏观及微观组织,研究了裂纹产生的原因,同时提出了相应的防治方法。结果表明,焊接结构拘束度大、母材焊材材质的综合作用和不合适的局部结构设计,造成焊接操作难度大,焊接工艺控制不稳定,使得焊缝形状很难稳定,焊接接头残余应力过大和P-Ni低熔点共晶物的存在,是造成多处焊缝出现热裂纹(结晶裂纹)的主要原因。

Welding crack failure analysis for the transverse and longitudinal cracks in the heterogenic welding joints of a vehicle platt between 09CuPCrNi-A weathering steel and ferritic stainless steel is carried out in the paper by the analysis contrast of the welding material and base metal component and the macro and microstructure observation of the crack.Meanwhile,the causes,types of the cracks and control methods was researched too.The result shows that the degree of structural restraint,base metal and welding material combined effects and inappropriate local structure caused the difficulty of welding operation.The instability of process control makes it difficulty to stabilize the shape of the weld.So,high welding residual stress and low melting P-Ni eutecticum is the main reason of the weld hot cracking （solidification cracking）.