焊丝中钒对316L/T91焊缝显微组织及力学性能的影响

Effect of Vanadium in Welding Wire on Microstructure and Mechanical Properties of T91/316L Welding Joints

采用自行熔炼的4种焊丝(钒元素质量分数分别为0、0.2%、0.4%和0.6%),使用钨极氩弧焊(TIG)对316L奥氏体不锈钢和T91马氏体不锈钢进行了焊接,探究了钒元素对焊接接头组织和性能的影响。研究结果表明,4种焊丝所得的焊缝组织都是由奥氏体加δ铁素体组成,随着焊丝中钒元素含量的增加,焊接接头的焊缝组织变得更加细小均匀;焊缝抗拉强度有一定程度提升;冲击吸收功数值变化不大,从冲击断口图中可看出,韧窝尺寸有所增加,说明钒对冲击韧性有改善作用,但效果有限。未添加钒时,T91侧熔合线附近硬度明显高于其他区域的,且存在较大幅度波动,添加钒元素后,该区域的硬度降低。

The effect of vanadium on the microstructure and mechanical properties of 316L/T91 tungsten inert gas(TIG)welding joints fabricated by four welding wires with the vanadium contents of 0, 0.2%, 0.4% and 0.6% was investigated. The results show that the weld microstructure of the four welding wires is composed of austenite and δ ferrite. With the increase of the vanadium content in the welding wire, the microstructure of the welded joint becomes more fine and uniform;the tensile strength is improved, the impact absorption energy does not change much. It can be seen from the impact fracture that the dimple size increases to some extent with the increase of the vanadium content, indicating that vanadium has a certain improvement effect on impact toughness, but the effect is limited. The microhardness near the fusion line on the T91 side is significantly higher than that of other regions without vanadium, and there is a large fluctuation. After adding vanadium, the hardness in this region decreases.