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采用D856-10焊条对12Cr1MoV钢进行焊接,通过金相观察、冲击试验和扫描电镜分析,研究了焊后直接空冷及焊后不同回火保温时间对12Cr1MoV钢焊缝显微组织、冲击韧性和断口形貌的影响。结果表明:焊后空冷条件下,焊缝主要为粗大的片状马氏体,脆性较高,缺口冲击韧性最低,为18 J,断面出现大面积的扩展区,且呈放射花样,断口韧窝较浅,表现为典型的解理断裂。焊后随着回火保温时间的延长,焊缝逐渐转变为细小的板条状回火马氏体及粒状回火索氏体,焊缝缺口冲击韧性明显改善,同时焊缝断面出现部分纤维区和剪切唇。当焊后热处理条件为750℃×6 h时,焊缝主要为分布均匀的粒状回火索氏体,韧性较高,为45 J,断面的断裂韧窝数量较多,表现为准解理断裂。
The welding of 12Cr1MoV steel with D856-10 electrode was carried out. The microstructure, impact toughness and fracture of 12Cr1MoV steel were studied by metallographic observation, impact test and scanning electron microscope analysis. Topography impact. The results show that the weld is mainly coarse sheet martensite under air-cooled condition with high brittleness and the lowest notched impact toughness of 18 J, with a large area of expansion in the section, with radiating patterns, fracture dimples Shallow, manifested as a typical cleavage fracture. Welding with the tempering holding time, the weld gradually transformed into small slab-like tempered martensite and granular tempered sorbite, weld notched impact toughness improved significantly, while the weld section of some fiber area And cut the lip. When the post-weld heat treatment condition is 750 ℃ × 6 h, the weld is mainly composed of uniformly distributed granular tempered sorbite, with a higher toughness of 45 J and a larger number of fractured dimples in the section, showing quasi-cleavage fracture .