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为了在钢材表面制备出质量良好、组织细化的镍基合金激光熔覆层,采用激光熔覆技术,在A3钢表面进行了镍基合金粉末添加Nb2O5的熔覆试验.通过对激光熔覆工艺参数及Nb2O5含量的优选得到了质量良好的熔覆层.使用金相显微镜、扫描电镜、电子能谱和X射线衍射仪对熔覆层进行了显微组织和物相分析,并测试了熔覆层显微硬度及摩擦性能.结果表明,当Nb2O5含量为15%,激光功率1.4 kW,扫描速度2 mm/s时,可以获得无裂纹、无气孔且与基底呈冶金结合的质量良好的熔覆层.Nb2O5的加入既提高了镍基合金熔覆层中的强化相比例,又细化熔覆层的组织,抑制粗大针状脆性硬质相的形成,降低熔覆层的裂纹敏感性.Nb2O5/Ni60激光熔覆层的硬度虽然降低,但耐磨性比纯Ni60提高约一倍.
In order to prepare a good quality and finely structured Ni-based laser cladding layer on the surface of the steel, laser cladding technology was used to test the cladding of Nb2O5 on the surface of A3 steel by laser cladding technology Parameters and Nb2O5 content of the coating has good quality obtained by using the metallographic microscope, scanning electron microscopy, electron spectroscopy and X-ray diffraction of the cladding layer was microstructure and phase analysis, and tested the cladding The results show that when the content of Nb2O5 is 15%, the laser power is 1.4 kW and the scanning speed is 2 mm / s, a good quality cladding with no cracks, no pores and metallurgical bond with the substrate can be obtained The addition of Nb2O5 not only enhanced the proportion of strengthening phase in the Ni-based alloy cladding layer, but also refined the microstructure of the cladding layer, inhibited the formation of coarse needle-like brittle hard phase and reduced the crack sensitivity of the cladding layer. Although the hardness of the Ni60 laser cladding layer is reduced, its wear resistance is about doubled than pure Ni60.