异种不锈钢电子束焊接接头的组织与性能

Microstructure and mechanical properties of electron beam welded joints of dissimilar stainless steel

采用自熔电子束焊与添加Ni金属箔电子束焊两种工艺以相同的焊接参数对430铁素体不锈钢与316L奥氏体不锈钢进行焊接,研究其焊接接头的组织与性能。结果表明:自熔焊缝金属的组织主要为δ-ferrite,晶界无定型马氏体与魏氏形态马氏体分别分布在δ-ferrite的晶界与晶内,残留奥氏体分布在这些马氏体内。添加Ni金属箔的焊缝金属的组织由粗大的奥氏体柱状晶构成。自熔焊缝金属的硬度显著高于添加Ni金属箔的焊缝金属,同时自熔焊缝金属的室温冲击韧性也高于添加Ni金属箔的焊缝金属。热力学分析表明,添加Ni金属箔的焊缝金属为完全的奥氏体凝固模式,形成的粗大奥氏体柱状晶稳定性高,在室温不发生TRIP效应,导致了以上反常现象。

The welding of 430 ferritic stainless steel and 316 L austenitic stainless steel was carried out by autogenous electron beam welding and nickel filler electron beam welding with the same welding parameters,and microstructure and properties of the electron beam welded joints were studied.The results show that the microstructure of the autogenous weld metal(WM)is mainlyδ-ferrite,and the grain boundary allotriomorph martensite and Widmanstatten shape martensite are distributed in theδ-ferrite grain boundary and crystal,respectively,and the residual austenite is distributed in these martensite.The microstructure of the nickel filler weld metal consists of coarse austenitic columnar grains.The hardness of the autogenous weld metal(320 HV)is significantly higher than that of the nickel filler weld metal(150 HV),and the room temperature impact toughness of the autogenous weld metal is also higher than that of the nickel filler weld metal.The thermodynamic analysis shows that the nickel filler weld metal is a complete austenite solidification mode,and the coarse austenite columnar crystal has high stability and no TRIP effect at room temperature,which leads to the above abnormal phenomenon.