不同焊接方法下316L不锈钢焊接接头组织性能研究

Study on Microstructure and Properties of Welded Joints of 316L Stainless Steel Welded by Different Welding Methods

采用20%CO2+80%Ar气体保护MAG焊和焊条电弧焊对316L不锈钢进行焊接,通过对焊接接头进行拉伸、弯曲、硬度试验和显微组织观察,研究了焊接接头组织性能。结果表明,焊条电弧焊接头的抗拉强度和显微硬度比MAG焊接头的抗拉强度和显微硬度高;焊条电弧焊焊缝金属中δ铁素体含量比MAG焊焊缝金属中δ铁素体含量高;MAG焊焊缝金属含有少量的MC型碳化物;拉伸时,焊条电弧焊接头断裂在热影响区,而MAG焊接头断裂在焊缝中心位置;焊接接头的弯曲试验均合格。

316L stainless steel was welded by both MAG welding process with 20%CO2 plus 80%Ar mixed shielding gas and SMAW process.The properties of the welded joints were studied by microstructure observation,tensile test,microhardness and bending test.The results show that the tensile strength and microhardness of SMAW welded joint are higher than those of MAG joint metal.The content of δ ferrite in SMAW joint metal is higher than that of MAG joint metal and MAG weld metal contains a small amount of carbides in the form of MC.The welded joint metal fractures in weld metal center of MAG welded joints,and in the heat-affected zone metal for SMAW welded joints.The bending properties of both SMAW joints and MAG joints with 20%CO2 plus 80%Ar mixed shielding gas are qualified.