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将18Ni马氏体时效钢电子束焊缝在48℃进行时效处理,时效处理时间分别为1.5、2.5、4.5和6h。采用金相显微镜、扫描电镜观察了不同时效状态下的18Ni马氏体时效钢电子束焊缝的微观组织,测试了不同时效状态下焊接接头的拉伸强度和接头不同区域的硬度值,并用扫描电镜分析了拉伸断口形貌。结果表明,随着时效时间的延长,沉淀粒子粗化引起了过时效,同时马氏体开始逆转变为奥氏体和铁素体,使钢的强度逐渐下降,经480℃,4.5h时效处理后,焊接接头的拉伸强度最高。
18Ni martensitic steel electron beam welding aging at 48 ℃ aging treatment time were 1.5,2.5,4.5 and 6h. The microstructures of 18Ni martensitic steel electron beam welded joints under different aging conditions were observed by optical microscope and scanning electron microscope. The tensile strength and the hardness of different regions of welded joint under different aging conditions were measured. Electron microscopy analysis of tensile fracture morphology. The results showed that as the aging time prolonged, the precipitated particles roughened caused over-aging, and martensite began to reverse into austenite and ferrite, the strength of steel decreased gradually after 480 ℃, 4.5h aging treatment After the weld joint tensile strength of the highest.