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根据激光焊接的特点,设计了适用于激光焊接厚船用板的坡口,分别采用纯激光焊和激光-MIG复合焊,用5道焊接实现了24mm船用厚板的激光焊接。对焊缝的宏观截面检测,发现存在少量的分散气孔,没有裂纹。对焊后的组织和硬度趋势进行了分析,结果表明:焊缝组织主要为板条马氏体和上贝氏体;热影响区的粗晶区以粗大的板条马氏体为主,细晶区以细小的粒状贝氏体和板条马氏体为主;焊缝重叠区域的主要组织为粒状贝氏体和板条马氏体;沿焊缝中心线从上到下硬度的总体趋势是逐渐降低;硬度值在热影响区细晶区达到最大,小于380HV,满足船用技术要求。
According to the characteristics of laser welding, a groove designed for laser welded thick shipboard was designed. Pure laser welding and laser-MIG composite welding were respectively used to weld the 24mm ship thick plate with 5 welding. Macro-section test of the weld, found that there is a small amount of dispersed pores, no cracks. The microstructure and hardness trend of the welded joints were analyzed. The results show that the weld microstructure mainly consists of lath martensite and upper bainite. The coarse-grained heat affected zone mainly consists of coarse lath martensite and fine The grain size is mainly composed of granular granular bainite and lath martensite. The main microstructure of the overlapping region of the weld is granular bainite and lath martensite. The overall trend of hardness along the center line of the weld from top to bottom Is gradually reduced; hardness value in the heat affected zone fine grain reached the maximum, less than 380HV, to meet the technical requirements of the ship.