不同焊丝TIG焊SUS316L/15CrMo异种钢接头的显微组织与力学性能

Microstructure and Mechanical Properties of SUS316L/15CrMo Dissimilar Steel Joint by TIG Welding with Different Welding Wires

分别采用ERNiCrMo-3镍基合金焊丝和ER309不锈钢焊丝,通过钨极惰性气体保护(TIG)焊工艺对SUS316L不锈钢和15CrMo低合金钢进行异种钢焊接,对比研究了2种焊接接头的显微组织和力学性能。结果表明:采用ERNiCrMo-3与ER309焊丝所得焊缝的凝固模式分别为奥氏体与奥氏体-铁素体凝固模式,凝固组织分别为完全奥氏体组织与奥氏体-铁素体混合组织;相较于ER309焊丝,使用ERNiCrMo-3焊丝可以抑制15CrMo钢侧焊接过程中的碳元素扩散,获得具有更高抗拉强度和断后伸长率的焊接接头;2种焊接接头的峰值硬度均出现在15CrMo钢侧的粗晶热影响区,采用ERNiCrMo-3焊丝所得焊缝因存在Laves相,硬度比采用ER309焊丝时高出30 HV左右。

Dissimilar steel welding was carried out on SUS316L stainless steel and 15CrMo low-alloy steel by tungsten inert gas(TIG) welding with nickel base alloy welding wire ERNiCrMo-3 and stainless steel welding wire ER309.The microstructure and mechanical properties of the two welded joints were studied and compared.The results show that the solidification modes of the welds obtained with ERNiCrMo-3 and ER309 welding wires were austenitic and austenite-ferrite solidification modes,respectively,and the solidification structures were complete austenitic and mixed austenite-ferrite structures,respectively.Compared with using ER309 welding wire,using ERNiCrMo-3 welding wire could inhibit the diffusion of carbon in the welding process on 15CrMo steel side,and obtain a welded joint with higher tensile strength and percentage elongation after fracture.The peak hardness of the two welded joints appeared in the coarse-grained heat affected zone on 15CrMo steel side.Due to Laves phase in the weld obtained with ERNiCrMo-3 welding wire,the hardness was about 30 HV higher than that with ER309 welding wire.