45钢表面激光熔覆SiC/WC增强316L复合涂层的组织和性能研究

李成; 雒设计; 韩礼红; 何勇

doi:10.14158/j.cnki.1001-3814.25011016

45钢表面激光熔覆SiC/WC增强316L复合涂层的组织和性能研究

Study on Microstructure and Properties of SiC/WC Reinforced 316L Composite Coating by Laser Cladding on 45 Steel Surface

摘要

摘要: 采用激光熔覆技术制备了3种复合涂层（SiC增强316L复合涂层、WC增强316L复合涂层、FeCr合金涂层），并使用OM、SEM、XRD对涂层显微组织、物相组成进行了分析，使用显微硬度仪、摩擦磨损试验机对其显微硬度及摩擦磨损性能进行了测定。结果表明：SiC增强316L复合涂层主要由SiC、γ-Fe相组成；WC增强316L复合涂层主要由WC、γ-Fe相组成；FeCr涂层由Fe-Cr相组成。随着扫描速度增加，熔池冷却速度加快，结晶过程中原子扩散时间缩短，形成了更细小且均匀的晶粒结构，从而提高了涂层的硬度和耐磨性，降低了摩擦系数。直观的体现为涂层截面平均显微硬度提高，涂层晶粒明显细化，摩擦系数减小，耐磨性提高。对3种涂层来说，3 mm/s的SiC增强316L复合涂层、WC增强316L复合涂层、FeCr涂层平均硬度分别为320、308、270 HV0.2,5 mm/s的SiC增强316L复合涂层、WC增强316L复合涂层、FeCr涂层平均硬度分别为380、370、305 HV0.2。各涂层摩擦系数大小顺序为：45钢基体（0.8）>WC-3(0.59)>SiC-3(0.45)>WC-5(0.42)>SiC-5(0.4)。在3种涂层中，5 mm/s扫描速度下制备的SiC增强316L复合涂层具有最大的平均显微硬度380 HV0.2，约为基体的2.7倍，摩擦系数为0.4，约为基体的1/2，表现出较好的耐磨性能，涂层磨损机制为磨粒磨损。

Abstract: Three kinds of composite coatings(SiC-reinfoned 316L composite coating, WC-reinfoned 316L composite coating, FeCr alloy coating) were prepared by laser cladding technology, and the microstructure and phase composition of the coatings were analyzed by using OM, SEM and XRD. The microhardness and friction and wear properties were determined by using microhardness tester and friction and wear tester. The results show that the SiC-reinfoned 316L composite coating is mainly composed of SiC and γ-Fe phases; the WC reinfoned 316L composite coating is mainly composed of WC and γ-Fe phases; and the FeCr coating is composed of Fe-Cr phases. With the increase of scanning speed, the cooling speed of the molten pool is accelerated, the atomic diffusion time in the crystallization process is shortened, and a finer and more uniform grain structure is formed, which improves the hardness and abrasion resistance of the coating and reduces the coefficient of friction. Intuitively, the average microhardness of the coating cross-section is increased, the coating grain is obviously refined,the coefficient of friction is reduced, and the abrasion resistance is improved. For the three coatings, the average hardness of 3 mm/s SiC-reinfoned 316L composite coating, WC reinfoned 316L composite coating, FeCr coating is 320 HV0.2, 308HV0.2, 270 HV0.2, respectively, and the average hardness of 5 mm/s SiC-reinfoned 316L composite coating, WC-reinfoned 316L composite coating, FeCr coating is 380HV0.2, 370 HV0.2, 305 HV0.2. The size of the coefficient of friction of each coating is in the following order: 45 steel matrix(0.8)>WC-3(0.59)>SiC-3(0.45)>WC-5(0.42)>SiC-5(0.4).Among the three coatings, the SiC-reinforced 316L composite coating prepared at a scanning speed of 5 mm/s has the largest average microhardness of 380 HV0.2, which is about 2.7 times than that of the substrate, and the coefficient of friction is 0.4,which is about half of that of the substrate, and it exhibits a better wear-resistant performance, and the wear mechanism of the coating is abrasive wear.

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