固溶处理对304/Q245R焊接接头组织及性能的影响

为研究固溶处理对304奥氏体不锈钢和Q245R碳钢异种金属焊接接头显微组织及性能的影响,采用E309-16奥氏体不锈钢焊丝对6 mm厚的304/Q245R板材进行手工电弧焊,焊后使用箱式电阻炉对焊接接头进行固溶处理,对焊接接头进行显微组织观察和力学性能测试.结果表明:相对于固溶处理前,固溶处理后的接头焊缝组织为灰色奥氏体和黑色铁素体,枝晶偏析程度明显降低,Cr、Ni等合金元素分布较为均匀;焊缝和碳钢侧热影响区硬度值均有所提高,最高硬度值为304.59 HV,出现在焊缝位置;接头抗拉强度较高,达570 MPa,拉伸断裂发生在母材Q245R碳钢部位.另外,对焊缝进行XRD测定,未检测到不利于接头性能的相,这表明固溶处理后的异种金属接头性能良好,能够满足工程中的实际需求.

Effect of solution treatment on microstructure and properties of 304/Q245R welded joint

In order to investigate the effect of solution treatment on microstructures and mechanical properties of welded joint made of two dissimilar metals 304 austenitic stainless steel and Q245R carbon steel, the 304 and Q245R metal plates with thickness of 6 mm were welded together by the manual arc welding method with E309-16 austenitic stainless welding wire. After welding, the welded joint was solution-treated in the box resistance furnace. The microstructures and mechanical properties of the welded joint were analyzed and investigated by means of microstructure observation and mechanical property testing. The results show that compared to the welded joint without solution treatment, the microstructures of weld are gray austenite and black ferrites, dendritic segregation alleviated, and the alloy elements especially Cr and Ni are uniformly distributed. The micro-hardness are increases for the welding seam and welding heat affected zone of carbon steel, and the highest micro-hardness ia about 304.59 HV in the welding seam. The ultimate tensile strength of the welded joint is improved to a maximum value of 570 MPa, moreover the fracture happens in the Q235R carbon steel. In addition, XRD analysis shows that no harmful phase affect the mechanical properties of welded joint. The research results indicat that the mechanical properties of welded joint made of dissimilar metals are significantly improved by solution treatment.