两种热作模具钢高温耐磨性对比研究

A Comparison of Wear Resistance of Two Types Hot-Work Die Steels at High Temperature

在UMT-3高温摩擦磨损试验机上对两种热作模具钢的高温摩擦磨损特征进行了研究,通过扫描电子显微镜(SEM)和X射线衍射仪(XRD)等检测手段对磨损表面和截面的形貌特征及物相进行分析.试验结果表明:SDCMSS钢有较H13钢高的高温耐磨性.在试验温度范围,SDCM-SS钢摩擦系数和磨损率要小于H13钢.SDCM-SS钢在400~700℃发生轻微氧化磨损机制;H13钢在400~500℃发生轻微氧化磨损机制,600和700℃发生严重氧化磨损机制.SDCM-SS钢高氧化性和高热稳定性能使新型模具钢具有较H13钢更宽的轻微氧化磨损温度区间,从而具有好的高温耐磨性能.700℃时,SDCM-SS钢的碳化物在摩擦过程中会聚集在摩擦氧化物层与基体交界面形成碳化物层.此碳化物层有益于提高热作模具钢的高温耐磨性.

The friction and wear behaviors of two type hot-work die steel were studied at high temperature on the UMTS teat system. The morphology features and phase of worn surface and subsurface were analyzed by scanning electron microscope and X-ray diffractometer. The results show the SDCM-SS steel presented higher wear resistance than H13 steel at high temperature. The wear rate and friction coefficient of SDCM-SS steel was less than H13 steel under the same condition at elevated temperature. Mild oxidative wear was the dominated wear mechanism for SDCM-SS steel at400 to 700. However, mild oxidative wear was the dominated wear mechanism for H13 steel at 400 and 500; severe oxidation wear was the mainly wear mechanism for H13 steel at temperatures up to 600 and 700. The high oxidation resistance and temper stability rendered SDCM-SS steel wider temperature range of mild oxidative wear as well as higher wear resistance than that of H13 steel. A carbides layer at the boundary of matrix and tribo-oxide layer was due to the aggregation of carbides during sliding. This carbides layer was beneficial to the high temperature wear resistance of hot working die steel.