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对３０ＣｒＭｏ＆４０ＣｒＮｉ钢的焊接冷裂敏感性进行了研究，确定了采用手工电弧焊焊接３０ＣｒＭｏ＆４０ＣｒＮｉ钢的焊接材料。用透射电镜观察了ＨＡＺ组织的精细结构。结果表明，１００℃预热、２５０℃×２ｈ紧急后热热影响区粗晶区可得到对防止冷裂纹有利的、以位错板条马氏体和下贝氏体为主、带有少量孪晶片状马氏体的显微组织。这不仅为评定３０ＣｒＭｏ和４０ＣｒＮｉ的抗裂性能提供了理论依据，而且对实际焊接生产具有重要的指导意义。
The cold cracking susceptibility of 30CrMo & 40CrNi steel was studied, and the welding materials of 30CrMo & 40CrNi steel by manual arc welding were determined. The microstructure of HAZ was observed by transmission electron microscopy. The results show that cold pre-heating at 100 ℃ and post-emergency heat-affected zone at 250 ℃ for 2h are favorable for preventing cold cracks. The main lapses are martensite and lower bainite with a small number of twins Wafer martensite microstructure. This not only provides a theoretical basis for evaluating the crack resistance of 30CrMo and 40CrNi, but also has important guiding significance for the actual welding production.