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通过金相观察、硬度试验和扫描电镜分析,研究了不同焊后热处理保温时间对ASTM 4130钢焊接热影响区显微组织、硬度、低温冲击韧性和断口形貌的影响。结果表明,随焊后热处理保温时间的延长,热影响区硬度降低,粗晶区和细晶区韧性明显改善;经焊后热处理后,热影响区组织主要为回火马氏体、铁素体和贝氏体;造成粗晶区硬度较高、韧性较低的主要原因是该区出现了贝氏体和粗大的回火马氏体。
The effects of different post-weld heat treatment holding time on microstructure, hardness, low temperature impact toughness and fracture morphology of the heat affected zone (HAZ) of ASTM 4130 steel were studied by metallographic observation, hardness test and scanning electron microscopy. The results show that with the increase of holding time after heat treatment, the hardness of HAZ decreases, and the toughness of coarse grain and fine grain decreases obviously. After heat treatment, the microstructure of HAZ mainly consists of tempered martensite, ferrite And bainite; the main reason for the higher hardness and lower toughness of the coarse-grained zone is the presence of bainite and coarse tempered martensite in the zone.