激光熔覆层宽度对汽轮机转子表面综合跳动特性的影响

为解决大型汽轮机转子轴轴颈磨损的修复问题,基于同轴送粉半导体激光熔覆再制造系统,采用激光熔覆再制造方法,以汽轮机转子轴材料为基体,利用激光熔覆再制造专用粉末作为实验材料,针对不同激光熔覆层宽度对汽轮机转子综合跳动的影响进行实验研究与机理模拟验证。结果表明,综合跳动特性与探头直径和激光熔覆层宽度相关,激光熔覆层宽度决定了汽轮机转子表面磁力线、电涡流密度与磁通量密度分布。当激光再制造层宽度小于8mm时,由于磁力线与表面电涡流密度受基体的干扰,磁通量密度在激光熔覆层的边缘出现突变,实际综合跳动的测量值为基体与激光熔覆层综合作用的结果,造成测量结果偏大。根据数值模拟计算被测金属体表面磁通量密度分布结果,激光熔覆层宽度的临界值为9.82mm。

Effects of Laser Cladding Layers Width on Total Indicated Runout Characteristics of Steam Turbine Rotor Surface

In order to solve the wear repair problem of large steam turbine rotor shaft journal, the material of steam turbine rotor shaft as substrate and the self-made special laser cladding remanufacturing powder as experimental material, the experiments were carried out by laser cladding remanufacturing method based on laser cladding remanufacturing system with coaxial powder feeder. Focusing on effect of different width of laser cladding layers on total indicated runout (TIR) of steam turbine rotor, the experiment research and mechanism simulation verification were performed, and the influence mechanism of different factors were analyzed. The results show that the data results of total indicated runout are closely related to probe diameter and laser cladding layer width. The width of cladding layer determines the turbine rotor surface magnetic, eddy current density and magnetic flux density distribution. Due to the interference of matrix magnetic field and eddy current density of surface, the magnetic flux density suddenly changes in the laser cladding layer edge when the laser cladding layer width is less than 8mm.The measurement results are too large caused by the comprehensive effect of substrate and laser cladding layer. According to the numerical simulation of magnetic flux density distribution of measured metal body surface, the critical value of laser cladding width is 9.82mm.