A novel test method was proposed to evaluate the crack resistance of high hardness coating prepared by laser cladding based on the self-restraint test in welding. In this method, the crack resistance of the coating was reflected by the crack rate, which was controlled by the restraint of the specimen. Consequently, the relationship between the restraint and the depth/width of the Y-groove could be demonstrated. As the depth of the Y-groove increased, the restraint of the specimen rose, while the increasing width of the Y-groove led to the decrease of the restraint of the specimen. Besides, the method was available for evaluating the crack resistance of different high hardness coatings. The evaluation results presented in excellent agreement with experimental data obtained by the tensile test. Furthermore, the empirical formulas of the relationship between the product of strength and plasticity, the crack rate, the depth, and the width of the Y-groove were also established. Besides, the high hardness crack-free coatings were prepared with appropriate preheating temperatures obtained by this method. The crack resistance test proposed in this study provided a general method for evaluating and preparing high hardness crack-free coatings.

提出了一种基于焊接自约束试验的激光熔覆高硬度涂层抗裂性评价新方法。在该方法中，涂层的抗裂性由开裂率来反映，开裂率由试样的约束来控制。因此，可以证明约束与 Y 形槽的深度/宽度之间的关系。随着Y槽深度的增加，试样的约束力上升，而Y槽宽度的增加导致试样的约束力减小。此外，该方法还可用于评估不同高硬度涂层的抗裂性。评价结果与通过拉伸试验获得的实验数据非常吻合。此外，建立了强度塑性乘积与Y型槽裂纹率、深度、宽度关系的经验公式。此外，通过该方法获得了适当的预热温度，制备了高硬度无裂纹涂层。本研究提出的抗裂性试验为评价和制备高硬度无裂纹涂层提供了通用方法。