低温渗氮对水泵用0Cr13Ni4Mo钢表面改性研究

Effect of Low Temperature Nitriding on Surface Modification of Pump with 0Cr13Ni4Mo Steel

为提高马氏体不锈钢0Cr13Ni4Mo的耐磨性,对水泵叶片进行表面处理,具体为分别在450℃、480℃和510℃对其进行2 h的盐浴渗氮。使用显微硬度计、XRD衍射仪、光镜、电化学工作站、摩擦磨损试验机及SEM等设备,研究了渗氮温度对0Cr13Ni4Mo钢的表面物相、硬度、渗层显微形貌、耐蚀性以及耐磨性的影响。结果显示:随着渗氮温度升高,物相由氮原子在马氏体中的过饱和固溶体α'N转变为Cr N和γ'相,材料点蚀电位下降,同时表面硬度增加,510℃处理后可达HV 1 200,渗层厚度为20μm,Cr N相大量析出,点蚀电位下降360 m V,磨损体积为未渗氮样品的17.6%,减磨效果明显。

To improve the wear resistance of 0Cr13Ni4Mo martensite stainless steel, the tempered steel was treated by salt bath nitriding at 450 ℃, 480 ℃ and 510 ℃ for 2 hours. The compositions, hardness, micromor- phology, corrosion resistance, wear resistance of nitrided layers were characterized by microhardness tester, X-ray diffractometer, electrochemical corrosion workstation, ball-on-disc tribometerr and scanning electron microscope. The results show that with the increasing of nitriding temperature, the phase transformed from α＇N nitrogen supersaturated solid solution in martensite substrate to CrN and γ＇. The pitting potential decreased and the surface hardness increased from HV 390 to HV 1 200 and case depth got to 20 μm at 510 ℃, which decreased Eb for 360 mV. Wear volume got a significant reduction, about 17.6 percent as the untreated sample.