Q235钢表面激光熔覆CoCrNi涂层的组织与性能研究

Study on the Microstructure and Properties of CoCrNi Coatings Prepared by Laser Cladding on Q235 Steel

摘要: 为改善Q235钢表面硬度及摩擦性能，采用预置粉末激光熔覆方法在Q235钢表面制备CoCrNi中熵合金涂层，研究不同激光功率对熔覆层宏观成形、显微硬度及摩擦性能的影响。结果表明，随着激光功率增加，熔覆层宏观成形质量和截面平均显微硬度均呈先改善后下降的趋势。1200 W时熔覆层表面连续、平整，成形质量较好，截面平均显微硬度达到489.375 HV0.2，为各组最高；CoCrNi熔覆层的摩擦系数均低于Q235钢基体，其中1300 W时平均摩擦系数最低，为0.5031。综合分析表明，适宜的激光热输入能够改善熔覆层成形质量，并提高其硬度和减摩性能，本试验条件下较适宜的激光功率范围为1200~1300 W。

Abstract: To improve the surface hardness and friction performance of Q235 steel, CoCrNi medium-entropy alloy coatings were prepared on the surface of Q235 steel by preset-powder laser cladding. The effects of different laser powers on the macroscopic morphology, microhardness, and friction properties of the cladded layers were investigated. The results show that, with increasing laser power, both the macroscopic forming quality and the average cross-sectional microhardness of the cladded layers first improved and then decreased. At 1200 W, the cladded layer exhibited a continuous and relatively smooth surface with good forming quality, and the average cross-sectional microhardness reached 489.375 HV0.2, the highest among all tested conditions. The friction coefficients of all CoCrNi cladded layers were lower than that of the Q235 steel substrate, with the lowest average friction coefficient of 0.5031 obtained at 1300 W. Overall, appropriate laser heat input can improve the forming quality, hardness, and friction-reducing performance of the cladded layer. Under the present experimental conditions, the suitable laser power range was 1200~1300 W.