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针对轴类零件的工作条件,采用激光熔覆的方法,在35CrMo钢表面熔覆3540铁基合金粉末和Ni00镍基合金粉末,借助光学显微镜、扫描电镜和显微硬度计等实验设备,研究了熔覆层的形貌、组织特征及显微硬度;通过拉伸实验设计,研究了熔覆层、熔覆层与基体之间的结合强度。研究分析结果表明,两种合金粉末都与基体形成了良好的冶金结合,无明显裂纹或气孔,熔覆层组织致密,晶粒细小。采用3540合金粉末制备的熔覆层的显微硬度高于Ni00合金粉末试样的熔覆层,而在熔覆区与熔合区交界处两种熔覆材料试样显微硬度差别不大,都明显高于基体的硬度,有利于提高零件的耐磨性。拉伸试验结果显示,3540合金粉末和Ni00合金粉末制备试样的平均抗拉强度分别为637.6 MPa和614.7 MPa,在进行拉伸实验过程中,断口出现在中间熔覆层,说明熔覆层与基体间实现了良好的冶金结合,拉伸过程没有出现明显的屈服现象。
Aiming at the working conditions of the shaft parts, 3540 iron-based alloy powder and Ni00 nickel-base alloy powder are cladding on the surface of 35CrMo steel by laser cladding method. With the aid of optical microscope, scanning electron microscope and microhardness tester, The morphology, microstructure and microhardness of the cladding layer were studied. The tensile strength of the cladding layer and the cladding layer was studied by tensile test. The results of the research and analysis show that both alloy powders form a good metallurgical bond with the matrix without obvious cracks or pores, the cladding layer is dense and the grains are small. The microhardness of cladding layer prepared by using 3540 alloy powder is higher than the cladding layer of Ni00 alloy powder sample, while the microhardness of two kinds of cladding material samples at the junction of cladding area and fusion area is not different Obviously higher than the hardness of the substrate, is conducive to improving the wear resistance of parts. Tensile test results show that the average tensile strength of 3540 alloy powder and Ni00 alloy powder prepared samples were 637.6 MPa and 614.7 MPa, respectively, during the tensile test, the fracture appeared in the middle cladding layer, indicating that the cladding layer and The matrix achieved a good metallurgical bond, with no apparent yielding during the drawing process.