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利用等离子束送丝熔覆技术在50Mn2合金结构钢表面制备耐磨熔覆层,研究主弧电流和扫描速度等工艺参数对熔覆层宏观形貌、显微组织及显微硬度影响。研究表明:主弧电流和扫描速度是影响熔覆层质量主要因素。随主弧电流增大,熔覆层焊道更连续且熔宽增大、余高先减后增,熔覆层中部组织形貌由胞状晶向树枝晶和等轴晶转变,组织以马氏体和铁铬碳共晶化合物为主,显微硬度较基体提高2~3倍;扫描速度越高,熔覆层焊道越不连续且易出现凹陷,熔宽和余高减小,显微组织形貌由胞状晶向树枝晶转变,其相组织仍以马氏体和铁铬碳共晶化合物为主,显微硬度随着扫描速度增大而增大,比基体硬度有很大提高。
The wear-resistant cladding layer was prepared on the surface of 50Mn2 alloy steel by plasma beam wire cladding and the influence of the main arc current and scanning speed on the macro-morphology, microstructure and microhardness of the cladding layer was studied. The results show that the main arc current and scanning speed are the main factors affecting the quality of the cladding. With the increase of the main arc current, the weld bead of the cladding layer is more continuous and the melting width increases, the residual height first decreases and then increases, the microstructure of the cladding layer changes from cellular crystal to dendrite and equiaxed crystal, and the microstructure changes with martensite and Fe-Cr eutectic compound is the main component, and the microhardness is 2 ~ 3 times higher than that of the matrix. The higher the scanning speed is, the less weld is continuous and prone to sag, melting width and residual height decrease, and the microstructure The morphology changes from cellular crystal to dendrite, and its phase structure is still dominated by martensite and ferrochrome eutectic compounds. The microhardness increases with the increase of scanning speed, which is much higher than that of the substrate.