深冷处理对20CrNiMo渗碳钢摩擦磨损性能的影响

Effect of Cryogenic Treatment on Friction and Wear Properties of 20CrNiMo Carburized Steel

为了提高20CrNiMo渗碳钢的摩擦磨损性能,对20CrNiMo渗碳钢进行了不同时间和不同循环次数的深冷处理。利用扫描电镜、洛氏硬度计等手段分析了深冷处理前后试样的微观组织、硬度和冲击韧性的变化情况;通过摩擦磨损试验机对比研究了深冷前后试样的摩擦磨损性能。结果表明:深冷处理对20CrNiMo渗碳钢表面硬度的影响有限;对冲击韧性有显著提高,深冷工艺为单次6 h时冲击韧性最高,较未深冷试样QT提高了10.9%。深冷处理后试样的平均摩擦系数和相对磨损率明显降低。当深冷工艺为单次6 h和3次每次3 h时,材料的摩擦磨损性能较好,平均摩擦系数分别为0.50、0.52,与QT试样相比,磨损率分别降低了25.9%、23.3%。

In order to improve the friction and wear properties of 20CrNiMo carburized steel,the cryogenic treatment was carried out on it for different durations and different cycles.The changes of microstructure,hardness and impact toughness before and after cryogenic treatment were analyzed by means of scanning electron microscope and Rockwell hardness tester.The friction and wear properties of samples before and after cryogenic treatment were compared and investigated by friction and wear testing machine.Results showed that the cryogenic treatment had a limited effect on the surface hardness of 20CrNiMo carburized steel.The impact toughnesses of the samples were significantly improved after cryogenic treatment,and the impact toughness was the highest when the sample was treated with a single cycle of 6 h cryogenic treatment,which was increased by 10.9%compared with the un⁃cryogenic sample(QT).The average friction coefficient and relative wear rate of cryogen⁃ic samples were significantly reduced.The samples treated with a single cycle of 6 h cryogenic treatment and 3 cycles of 3 h cryogenic treatment had better friction and wear properties,and the average friction coefficient were 0.50 and 0.52 respectively.Compared with the QT samples,the wear rates were reduced by 25.9%and 23.3%respectively.