为了提高H13钢表面耐磨性能, 采用激光熔覆技术在H13钢表面制备NiCr/Cr3C2复合涂层。首先通过扫描电子显微镜和显微硬度计对涂层显微组织与硬度进行测试分析; 随后对涂层与H13钢基体进行室温干滑动摩擦磨损试验, 并根据涂层的磨损形貌、磨损失重、摩擦系数曲线展开分析, 探究涂层的耐磨性能及其磨损机制。研究结果表明: 涂层微观组织主要由枝晶、柱状晶及胞状柱状晶组成, 涂层整体的显微硬度大于基体, 其平均显微硬度是基体的2.5倍; 在相同磨损工况下, 涂层的耐磨性明显优于基体, 其中涂层和基材的平均摩擦系数分别为0.488 3和0.678 7, 基材的平均磨损量为涂层的3.6倍。H13钢基体的磨损机制为混合粘着与磨粒磨损, 而涂层为轻微磨粒磨损与疲劳磨损, 表明在H13钢表面激光熔覆NiCr/Cr3C2合金粉末涂层可以显著提高其耐磨性能。

NiCr/Cr3C2 coatings were prepared on H13 steel by laser cladding. The microstructure and hardness of the coating were characterized by scanning electron microscope and microhardness tester. Then the wear resistance properties of the coating and H13 steel were tested by dry sliding friction and wear tester at room temperature. The wear resistances of the coating were investigated according to the wear morphology, the wear weight loss and the friction coefficient curve. The results show that the coating consists of dendrite, columnar crystals and cellular columnar crystals. In addition, the microhardness of the coating is higher than that of the matrix because the average microhardness of the coating is 2.5 times of the matrix. In the same wear condition, the wear resistance of the coating is obviously better than that of the matrix. The average friction coefficients of the coating and substrate are 0.488 3 and 0.678 7. And the average wear amount of the substrate is 3.6 times of the coating. Besides, the wear mechanism of the H13 steel matrix is mixed adhesion and abrasive wear while the coating is abrasive and fatigue wear. The results show that laser cladding NiCr/Cr3C2 alloy on H13 steel can significantly improve its wear resistance.