焊接电流对汽车曲轴氩弧熔覆修复涂层组织与耐磨性的影响

Effect of Welding Current on Microstructure and Properties of Wear-resistant Coating Prepared by Argon Arc Cladding on Automobile Crankshaft

以中碳锰铁、高碳铬铁,硅铁、碳化硼、钒铁、石墨、钛铁以及还原铁粉等作为预制合金粉末,通过氩弧熔覆技术在基体表面制备出一层耐磨性良好的涂层。同时,借助光学显微镜、硬度计以及UMT-2摩擦磨损试验机等实验仪器对耐磨涂层的组织和耐磨性能进行了研究分析。结果表明:随着氩弧熔覆电流的增加,碳化物M_(23)C_6的含量先增加后减少。在电流为150 A时,涂层中的碳化物M_(23)C_6含量达到最大,且此时碳化物M_(23)C_6的晶粒尺寸也相应达到最大。此外,随着焊接电流的增加,硬度与耐磨性都整体呈先增加后减小的变化规律。在电流为110 A时,涂层硬度最小,磨损损失高达36 mg,耐磨性最差;而当电流为150 A时,涂层硬度达到最大值,磨损损失减小到8 mg左右,此时的耐磨性达到最佳。

The coating with high strength, high hardness and high wear resistance was prepared by laser cladding using Fe-Mn, high carbon ferrochrome, Fe-Si, B4C, Fe-V, graphite and Fe as major raw material. The microstructure and properties of the coating were investigated by optical microscopy, hardness tester and UMT-2 friction and wear test machine. The results show that with the increase of the welding current, the content of M23C6 firstly increases and then decreases. When the current is 150A, the content of M23C6 reaches peak and the grain size is also very big. In addition, with the increase of the current, the hardness and wear resistance firstly increase, then decline. When the current is 110A, the hardness is very low and the wear weightlessness is as high as 36 mg, then the wear resistance is very poor. While the current is 150A, the hardness is very high and the wear weightlessness is 8mg, then the wear resistance is very good.