SDAH13钢铝含量和离子氮化工艺优化及高温磨损性能

Optimization of Aluminum Content and Plasma Nitriding Process of SDAH13 Steel and High Temperature Wear Resistance

铝元素对模具钢的离子氮化工艺和性能具有重要影响,适当的铝含量可以改善模具钢渗层质量,显著提高其表面硬度和耐磨性。通过正交试验和单变量试验研究了不同铝含量的SDAH13钢较优的离子氮化工艺及其高温磨损性能。利用OM、SEM、XRD表征了渗氮层的微观组织及物相,应用高温摩擦磨损试验机研究了SDAH13钢离子氮化前后的磨损性能,通过光学轮廓仪测量了磨损量并计算了磨损率,同时通过SEM观察了样品的磨损形貌并且进行了EDS能谱分析。研究结果表明:含铝质量分数为0.76%,氮化温度为540℃,保温时间14 h,炉压为400 Pa时,离子氮化效果较优;随着铝含量的增加,渗氮层厚度会减薄。在500℃条件下进行摩擦磨损实验时,与未氮化试样的磨损率比较,采用较优渗氮工艺进行离子氮化的Al0.76-SDAH13钢的磨损率能降低45%,其耐磨损性得到了显著提高。

Aluminum content plays an important role in the plasma nitridingprocess and the properties of die steels. The quality of nitriding layers, surface hardness and wear resistance can be remarkably improved by adding a certain amount of aluminum into die steels. By orthogonal experiments and single-variable experiments, SDAH13 die steels with different aluminum contents were studied in terms of the optimized plasma nitriding process and the properties of high-temperature wear resistance. The microstructure and phase compositions of the nitriding layers were studied by OM, SEM and XRD. The wear properties of the nitrided SDAH13 steels and samples without the plasma nitriding treatment were investigated by a high- temperature friction and wear tester, and the wear losses were tested by optical contour instruments. The wear rates were then calculated. Furthermore, the wear morphologies of the samples with wear tests were studied by SEM and EDS. The results show that the plasma nitriding is optimized when the content of aluminum is 0.76%, the temperature 540 ℃, the time 14 h, and the furnace pressure 400 Pa. Meanwhile, with the increasing amount of aluminum, the thickness of the nitriding layers becomes reduced. However, in the wear tests under 500 ℃, the wear rate of A10.76-SDAH 13 steels with the plasma nitriding treatment using the optimized nitriding process is reduced by 45% compared with the samples without the nitriding treatment, and the wear resistance of SDAH 13 die steels is significantly improved.