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为深入分析07MnCrMoVR钢热影响区的脆化问题,采用热模拟技术和显微观察技术,对该钢热影响区的组织和性能进行了深入研究。研究结果表明:单次热循环时,粗晶区(CGHAZ)和临界区(ICHAZ)韧性恶化严重,晶粒长大及粒状贝氏体、M-A组元等非平衡组织的形成是粗晶区韧性恶化的主要原因。随着t8/5的增加,粗晶区冲击韧性随之降低,为防止热影响区脆化,t8/5应控制在30 s之内。粗晶区+临界区(IRCGHAZ)是多道焊二次热循环时热影响区韧性最差的区域,引起IRCGHAZ脆化的原因是大量沿晶界分布的块状M-A组元的形成。
In order to deeply analyze the embrittlement of heat-affected zone of 07MnCrMoVR steel, the microstructure and properties of the heat-affected zone of the steel were studied in detail by using thermal simulation and microscopic observation techniques. The results show that the ductile toughness of CGHAZ and ICHAZ deteriorates seriously in single thermal cycle. The formation of unbalanced grains such as grain growth, granular bainite and MA component are the toughness of coarse grain The main reason for deterioration. With the increase of t8 / 5, the impact toughness of coarse grains decreases. To prevent the heat affected zone from embrittlement, t8 / 5 should be controlled within 30 s. The coarse grain region + critical region (IRCGHAZ) is the region with the worst toughness in the heat-affected zone during the multi-pass welding secondary heat cycle. The reason for the IRCGHAZ embrittlement is the formation of a large number of massive M-A components distributed along the grain boundary.