Page 46 - 摩擦学学报2025年第10期

第 10 期 关健, 等: 不同表面处理20CrMo与GCr15配对摩擦副的极端工况摩擦学行为研究 1443

reducers under extreme working conditions, such as heavy load, low speed and boundary lubrication. To improve the
tribological performance of the GCr15 (ball)-20CrMo (disk) friction pair in precision reducer, three different friction
pairs, GCr15-20CrMo with carburizing and twice quenching (FP1), GCr15-20CrMo with nitrocarburizing (FP2) and
GCr15-20CrMo with high concentration nitrocarburizing (FP3) were prepared. The high temperature (100 ℃) and heavy
load (maximum Hertzian contact pressure 4 GPa) tribological experiments were conducted by the UMT-5 testing
machine, followed by the high temperature and high speed(maximum sliding velocity 562 mm/s) tribological
experiments. The wear resistance performance of the three heat treatment technologies was evaluated based on the
micro-hardness, friction coefficient, microstructure morphology, element distribution, wear scar dimensions and wear
rate of the friction pairs. The hardness results demonstrated that carburizing and twice quenching heat treatment
technology could induce the highest hardness for 20CrMo. While the 20CrMo disk after nitrocarburizing exhibited the
lowest hardness value in the three friction pairs. The results of heavy load tribological experiments showed that abrasive
wear was the main reason for failure of the friction pairs. Under the condition of low speed (50 mm/s) and nominal speed
(300 mm/s), the friction coefficient of the three friction pairs was almost not influenced by variations of the heat
treatment technologies. The white light morphology results revealed that FP2 and FP3 had deeper furrows on
3
the 20CrMo disk, leading to higher wear rate values[183.61, 252.04 μm /(N·m) at low speed, and
3 3 3
19.21, 33.93 μm /(N·m) at nominal speed]. The wear rate of FP1 was relatively 94.47 μm /(N·m) and 10.46 μm /(N·m)
at low speed and nominal speed. In addition, the EDS analysis on the worn area of the three friction pairs indicated that
tribo-film was generated on the worn area attributed to the presence of P element. Notably, the P element content on the
worn area of FP1 (0.62%) was higher than that of FP2 (0.35%) and FP3 (0.39) at the relatively lower speed. It could be
concluded that the wear resistance of 20CrMo steel had been improved using carburizing and twice quenching
technology. In case of the heavy-load and high-speed condition, the P element content on the worn area of FP3 reached
0.53%, which was the highest in the three friction pairs. The wear rate of 20CrMo disk for FP1, FP2 and FP3 were
3 3 3
relatively 79.11 μm /(N·m), 42.33 μm /(N·m) and 34.45 μm /(N·m). High concentration nitrocarburizing technology was
beneficial for enhancing the tribological performance of 20CrMo steel. These findings further demonstrates that the wear
resistance performance of the 20CrMo steel was better with higher P element content in the tribo-film. The results of
high speed indicated that there were no furrows observed on the wear scar of the three friction pairs under nominal load
condition comparing with that under heavy load condition. FP1 presented the best wear resistance with the wear rate
3 3 3
value of 9.22 μm /(N·m), lower than the wear rate of FP2 [23.40 μm /(N·m)] and FP3 [23.56 μm /(N·m)]. This was due
to the highest surface hardness of 20CrMo disk processed by carburizing and twice quenching. This study provided a
significant theoretical reference for the improving of tribological performance and longevity of life for the gear friction
pairs in precision reducers.
Key words: precision reducer; extreme working condition; GCr15-20CrMo friction pair; carburizing; nitrocarburizing;
friction and wear; tribofilm

在工业4.0的进程中，工业机器人的发展具备极高 中的摆线轮-针齿接触区域的最大赫兹接触压应力将
的战略价值. 精密减速机作为工业机器人的核心零部 超过3 GPa，局部高接触压力会导致齿面发生早期磨
件，具有高刚度、高承载能力和高功率密度等优点. 据 损失效，降低减速机的使用寿命 [3-4] . 因此需要研究减
国际机器人联合会的统计数据，精密减速机的成本占 速机齿轮摩擦副在极端工况下的磨损机理，提高减速
据工业机器人总成本的30%以上，其年销售额超过 机齿轮摩擦副材料的抗磨损性能.
[1]
20亿美元 . 精密减速机的可靠性极大程度上影响工 20CrMo是1种低碳合金钢，因其优异的韧性及耐
业机器人的使用寿命，因此对于精密减速机的失效模 磨损性能、较高的淬透性和强度，通常都被用于重载
[5]
式和失效机理分析是非常关键的. 摆线减速机和RV 工况下的齿轮和轴承部件 . 淬火是齿轮钢和轴承钢
减速机因其高承载力和优异的精度保持性，在重载机 在服役前必须经历的工序，淬火工艺能够促进钢材料
器人领域拥有极大的优势. 摆线减速机和RV减速机 基体中微观组织的相变，提高材料的力学性能和耐磨

由两级传动组成，即低传动比齿轮系统(太阳轮-行星 损性能 [6-7] ，因此对于重载工况下的齿轮钢，可以通过
轮)和高传动比齿轮系统(摆线轮-针齿)，减速机的扭 调整淬火工艺来进行性能强化. 渗碳和渗氮也是齿轮
[2]
矩基本由摆线轮-针齿承担 . 在极端工况下，减速机 钢表面常用的处理方式，可以提升齿轮表面的耐磨