超高强淬火钢板中频点焊接头组织与断口形貌

Microstructure and fractography of intermediate frequency spot welding of precision ultra-high strength quenching steel

以超高强度淬火钢EN10292TL4225为研究对象,采用先进的中频点焊连接技术,利用优化的焊接参数实现了超高强钢同种材料之间的优质连接,进行了高强钢的点焊接头拉伸试验和焊点表面硬度分布试验以及对拉伸断口的扫描电镜分析.结果表明,试验得到的点焊接头具有良好的力学性能和接头组织形貌,焊接接头组织具有和母材一致的显微组织,断口形貌具有塑性韧窝的特征,能够满足汽车产品碰撞与道路试验设计的要求.

Precision ultra-high strength quenching steel EN 10 292 TL4225 was selected for the study.The intermediate frequency（IF）spot welding process,one kind of advanced jointing technologies,was used,and the perfect welded joints were obtained by using the optimum welding parameters.The mechanical properties of the joints,such as the tension strength,the hardness distribution,were tested,and the microstructure of the fracture was analyzed by scanning electron microscope.The test results show that the joints welded by using IF spot welding process has good mechanical properties,the microstructure of the joints is similar with that of the base metal,the fracture of the joints has the characteristics of plastic,and the mechanical properties completely meet the actual need of car product crash test and road testing.