工业机器人用SCM420钢行星齿轮热处理工艺的优化

针对工业机器人用SCM420钢制行星齿轮热处理畸变问题,采用改进的正火工艺以调整渗碳前的预备组织,并设计合理的装料方案和冷却方式等措施,同时在渗碳过程中采用阶梯升温的工艺,有效地控制了渗碳淬火过程中齿轮畸变。结果表明,采用优化正火后可得到均匀一致的铁素体+珠光体的组织,硬度为175 ~180 HBW。随后经渗碳淬火回火后,批量生产的行星齿轮表面硬度、心部硬度和有效硬化层深度均值分别为59.74 HRC、40.44 HRC和0.530 mm。渗碳层中的马氏体级别为1级,残留奥氏体和碳化物级别为1~2级;心部组织级别为1~2级。齿轮精度、平面翘曲、齿沟振幅和齿形齿筋等全部满足技术要求。

Optimization of heat treatment process of SCM420 steel planetary gear for industrial robot

Aiming at the heat treatment distortion problem of SCM420 steel planetary gears used in industrial robots,a modified normalizing process was used to adjust the preparatory microstructure before carburizing,and then the gear distortion during carburizing and quenching was effectively controlled by using various measures including reasonable loading scheme,cooling method,and stepped heating process during carburizing.The results show that after the modified normalizing process,a uniform ferrite+pearlite microstructure can be obtained with a hardness of 170 to 180 HBW.And after the carburizing quenching and tempering,the surface hardness,core hardness and effective case depth of the planetary gears with mass production are 59.74 HRC,40.44 HRC and 0.530 mm,respectively.The grade of martensite of carburized layer is level 1,and that of the retained austenite and carbides are level 1-2,and that of the core microstructure is level 1-2.The gear precision,plane warping,tooth groove amplitude and toothed ribs all meet the technical requirements.