Failure Analysis of Electron Beam Weld Joints for 18Ni Co-free Maraging Steels
Microstructure of two different 18Ni Co-free maraging specimens and their electron beam weld joints were investigated comparatively by optical microscopy and SEM. It is showing that both of the steels are typical lath martensite, however, one grain size is about three times as another one, and XRD reveals that the amount of the retained austenitic phase in the former is less then the latter. The austenite distributes in plate form along granular and lath boundaries while some in fine particle within the matrix. The microstructural difference between two specimens led to diverse behaviors in electron beam welding. The first specimen is weldable well but the second shows obvious welding defects of pits and burn-through holes in weld face. The welding microstructure exhibits a typical dendritic morphology, and the grains in the heat-affected zone recrystallized and grew up obviously for high temperature heated by welding electron beam. The weldablity is relative to the thermal conduction performance of the base materials,which is contributed greatly for grain size and austenite content.
莫德锋 HU Zheng-fei WANG Chun-xu HE Guo-qiu
同济大学
国内会议
长沙
英文
384-389
2007-11-03（万方平台首次上网日期，不代表论文的发表时间）