采用连续光纤激光器在小模数齿轮齿面制备1 mm厚的Ni60合金涂层,针对小模数齿顶较薄以及单道激光在齿轮中部能量过于集中易造成熔覆缺陷的原因进行分析,提出了采用双道激光在小模数齿面制备镍基合金涂层的方法,在保证激光总输入能量不变的条件下,将原有单束激光的能量按一定的能量配比方案分配到两个小光斑上,依次加工齿轮的齿顶和齿底。结果表明:采用双道1 mm 光斑按4∶6能量配比方案不仅减小了齿顶的烧蚀,还解决了齿轮中部能量过于集中的问题,涂层的稀释率显著降低,组织中含Fe、Ni的晶状奥氏体析出较少,富含Cr的粒状渗碳体析出较多,熔覆层组织整体的耐磨性和强度都优于单道激光熔覆层。双道激光熔覆工艺可显著提升小模数齿轮齿面镍基合金涂层的质量。

Laser cladding experiments on 1-mm-thick Ni60 alloy coatings on a small-modulus gear-tooth surface are conducted using a continuous fiber laser. The analysis on the reason for causing cladding defects by the thin small-modulus tooth top and single-pass laser concentrated in the middle of the gear is performed. A double-pass laser processing method is proposed for the fabrication of nicked-based alloy coatings on the small-modulus gear-tooth surface. Under the condition of constant laser energy input, the energy of the original single-pass laser is distributed to two small spots according to a certain energy ratio scheme. The gear's tooth top and bottom are then sequentially processed. Results show that by using two 1-mm spots with an energy ratio of 4∶6, the proposed method not only reduces the ablation of the gear's tooth top, but also solves the problem of excessive energy being concentrated in the middle of the gear. Additionally, the coatings' dilution rate significantly reduces. Low precipitation of crystalline austenite containing Fe and Ni is observed in the microstructure in contrast to the high precipitation of granular cementite rich in Cr. The wear resistance and strength of the cladding layer are improved compared to those of single-pass laser cladding. Overall, the double-pass laser cladding process significantly promotes the quality of the nickel-based alloy coatings prepared on the small-modulus gear-tooth surface.