球墨铸铁和铁素体不锈钢的激光-MIG复合焊接性能

Laser-MIG hybrid welding performance of spheroidal graphite cast iron and ferrite stainless steel

为了研究球墨铸铁(FCD450)和铁素体不锈钢(SUS430)的异种焊接性能,采用3种不同镍质量分数的焊丝对球墨铸铁和铁素体不锈钢进行激光-MIG复合焊接试验,并确定最佳焊接条件.通过光学显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)、电子探针(EPMA)和维氏硬度计对焊接接头的显微组织、成分分布及硬度分布进行分析,并对焊接接头进行拉伸试验.试验结果表明,在最佳焊接条件下,通过添加3种焊丝,焊接接头无裂纹出现且焊缝成型良好.由于焊丝的作用,焊缝金属铬和镍的质量分数较高.随着焊丝Ni质量分数的增加,焊缝宽度明显减小.由于莱氏体和马氏体的存在,拉伸试样都断在FCD450侧的半熔化区或热影响区.

In order to study the dissimilar welding performance of spheroidal graphite cast iron（FCD450） and ferrite stainless steel（SUS430）,the laser-MIG hybrid welding tests for FCD450 and SUS430 were carried out through adopting three kinds of welding wires with different mass fraction of Ni,and the optimum welding condition was determined.The microstructure,constituent distribution and hardness distribution of welding joints were analyzed with optical microscope（OM）,scanning electron microscope（SEM）,energy dispersive spectrometer（EDS）,electron probe microanalysis（EPMA） and Vicker＇s hardness tester.In addtion,the tensile tests were performed for the welding joints.The experimental results show that under the optimum welding condition,no crack is found in the welding joints and the welding performance is good with adding three kinds of welding wires.Due to the adoption of the welding wires,the mass fraction of Cr and Ni in the welding seam area is higher.With increasing the mass fraction of Ni in the welding wires,the width of welding seam obviously reduces.Due to the existence of ledeburite and martensite,the fracture of all tensile specimens occurs in the partial melting zone or heat affected zone（HAZ） at FCD450 side.