【摘要】 采用金相显微镜、透射电镜观察了焊后不同时效状态下T— 2 5 0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室温强度、夏比缺口冲击韧性、显微硬度 ,并用扫描电镜分析了拉伸断口形貌。结果表明 :随时效温度的升高 ,焊缝区枝晶间逆转奥氏体析出量增加 ,焊缝缺口冲击韧性增大 ,断口韧窝增大 ;但由于 5 0 0℃× 4h时效处理后焊缝马氏体孪晶较多而使其拉伸强度和缺口冲击韧性降低。经 4 80℃× 4h时效处理后 ,焊接接头强度具有最佳强韧性配合更多还原

【Abstract】 Microscopy and TEM are used to examine microstructure of T 250 EB weld metal under different ageing conditions.The ultimate tensile strength(UTS), charpy V noth(CVN) impact toughness and micro hardness of different ageing conditions of the weld joints are tested at room temperature, and SEM is used to analyse fracture appearance.Experimental results indicate that there exist reverted austenite dispersed along the interdendritic boundaries.Their amount of reversed austenite, CVN impact toughness and dimple of fracture increase with increase of post weld ageing temperature. After ageing at 500℃ for 4 h, tensile strength and charpy V noth impact toughness of weld metals decrease since there exist lots of twinned martensite in the weld fusion zone.Optimum strength and toughness are obtained by ageing at 480℃ for 4 h.更多还原