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用自动TIG焊在不同的焊接工艺条件下对35CrMoA钢进行焊接,并利用光学显微镜分析了焊接接头热影响区金属的显微组织,测试了焊接接头热影响区的显微硬度。结果表明,如焊前不预热,焊后不保温缓冷,焊接接头热影响区组织较粗大,得到较多的马氏体组织,硬度较高,热影响区的冲击韧性较差;焊前预热,焊后保温缓冷,并采用较小的焊接电流(100A),焊接接头热影响区组织细小,分布均匀,硬度分布合理,热影响区冲击韧性较好。
The welding of 35CrMoA steel was performed by automatic TIG welding under different welding conditions. The microstructure of the metal in the HAZ of the welded joint was analyzed by optical microscope. The microhardness of the HAZ of the welded joint was tested. The results show that if the steel is not preheated before welding and does not warm and then slowly cooled after welding, the microstructure of the HAZ of the welded joint is coarse and the martensite structure is more and the hardness is higher and the impact toughness of the HAZ is poorer. Preheating, slow cooling after welding and using a smaller welding current (100A), HAZ microstructure is small, uniform distribution, hardness distribution is reasonable, heat impact zone impact toughness better.