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在一定焊接参数下,利用氩气做保护气对20CrMnSi钢进行激光焊接,用光学显微镜观察了焊接接头的微观组织,用维氏硬度计测量了焊接接头的显微硬度。结果表明,焊接接头成形良好;焊缝组织为板条状马氏体,中心为细小的等轴晶,边缘为细小的柱状晶;过热区为马氏体和少量的珠光体,不完全正火区为马氏体与铁素体的混合组织;焊接接头的硬度分布不均匀,焊缝的硬度较母材的硬度高,焊缝边缘的硬度比焊缝中心的硬度高。
Under certain welding parameters, 20CrMnSi steel was laser welded by using argon as protective gas. The microstructure of welded joint was observed with light microscope. The microhardness of welded joint was measured with Vickers hardness tester. The results show that the welded joints are well formed. The microstructure of the weld is lath martensite, the center is fine equiaxed grains, and the edge is fine columnar grains. The overheated area is martensite and a small amount of pearlite is not completely normalized The martensite and ferrite mixed zone; hardness distribution of welded joints is not uniform, the hardness of the weld is higher than that of the base metal, the hardness of the weld edge is higher than the hardness of the weld center.