关键词: QPQ处理, 渗氮时间, 32Cr3MoVE钢, 渗氮层形貌, 硬度, 耐磨性, 耐蚀性

Abstract: QPQ treatment was carried out on 32Cr3MoVE steel for gears at 560 ℃ for different nitriding time (90, 120, 150 min), and its phase composition, nitrided layer morphology, microhardness, wear resistance, and corrosion resistance were tested. The results show that the nitrided layer is composed of Fe₂N, Fe₃N and Fe₃O₄ phases after QPQ treatment for different nitriding time. The main phase of the nitrided specimens for 90 min and 120 min is Fe₃N, while the main phase of the specimen nitrided for 150 min is Fe₂N. With the extension of nitriding time, the thickness of the compound layer increases. The specimen QPQ nitrided for 120 min has the highest hardness (932.4 HV0.1), the best wear resistance with wear loss of only 2.2 mg at dry friction, and the best corrosion resistance, with the lowest current density, and a passivation zone appearing in the polarization curve which is speculated to form a passivation film containing metal oxides during the corrosion process, and that delays the corrosion rate.

Key words: QPQ processing, nitriding time, 32Cr3MoVE steel, nitrided layer morphology, hardness, abrasion resistance, corrosion resistance