T92/Super304H异种钢焊接接头微观组织和硬度研究

Study on Microstructure and Hardness of T92/Super304H Dissimilar Steel Welded Joint

利用光学显微镜、扫描电镜、数字式显微硬度计和X-射线能谱分析仪等方法研究了T92/Super304H异种钢焊接接头的微观组织和硬度,分析了焊接接头的力学性能。结果表明:焊接接头的Super304H热影响区具有粗大的等轴奥氏体晶粒,T92焊缝熔合区的奥氏体晶粒和板条马氏体尺寸细小;在焊接过程中,由于受到焊接热循环作用,焊接接头中T92热影响区的硬度值最高;在高应力载荷条件下,高温拉伸试样断裂位置发生在T92热影响区,断口为韧窝断裂,以塑性穿晶断裂为主。

Microstructure and hardness of T92/Super304H dissimilar steel welded joint were studied by means of optical microscope,scanning electron microscope,digital micro-hardness tester and energy dispersive X-ray spectrometer,and the mechanical properties of welded joints were analyzed.Results show that the Super304H heat affected zone(HAZ)of welded joint has coarse equiaxed austenite grains,and the austenite grains and lath martensite in T92 fusion zone are fine.The hardness of T92 HAZ is the highest because of the welding thermal cycle during welding.Under high stress loading,the fracture position of high temperature tensile specimen occurs in T92 HAZ,and the dimple fracture is dominated by plastic transgranular fracture.