42CrMo钢活塞杆表面氧氮复合渗层的显微组织和耐磨性能

采用气体氧氮复合处理对42CrMo钢活塞杆进行表面改性和耐磨性能研究,通过金相分析、显微硬度测试及干摩擦磨损试验等方法对比分析了不同表面工艺处理后的试样组织和性能。结果表明: 调质态42CrMo钢经8 h气体氧氮复合处理后表面形成了1~2 μm由Fe₃O₄组成的氧化层及ε-Fe_2-3N和γ′-Fe₄N组成的约18 μm厚的化合物层,有效渗层的总厚度约为340 μm。在相同干摩擦条件下,未处理的基材试样与镀铬处理试样的磨损机制为磨粒磨损并伴随轻微粘着磨损。气体氧氮复合处理后试样具有最低平均摩擦因数和磨损率,磨损机制为磨粒磨损,耐磨性能最优。

Microstructure and wear resistance of oxynitriding layer on piston rod surface of 42 CrMo steel

Surface modification and wear resistance of 42CrMo steel piston rod were studied by using gas oxynitriding composite process. The specimens treated by different surface processes were characterized and analyzed by means of metallographic analysis, microhardness test and dry friction and wear test. The results show that after gas oxynitriding treatment of the quenched and tempered 42CrMo steel for 8 h, at which the surface composed of oxide layer of 1-2 μm with Fe₃O₄ and compound layer of 18 μm with ε-Fe_2-3N and γ′-Fe₄N can be obtained. The effective modified thickness is about 340 μm. Under the same dry friction conditions, the wear mechanism of the specimens without treatment and with chromium plating treatment is abrasive wear accompanied by slight adhesive wear. After gas oxynitriding composite process, the specimen has the lowest average friction coefficient and wear rate, and the wear mechanism is abrasive wear, which has the best wear resistance.