高速激光熔覆铁基自磨刃涂层及其性能研究

Iron-based Self-grinding Coating and Its Properties Prepared by High-speed Laser Cladding

摘要:

为提升铁基自磨刃的耐磨性能并改善农机零部件的使用寿命，在自磨刃模具(65 Mn)表面采用光纤同轴送粉激光熔覆技术，通过调控熔覆扫描速度，对Fe901硬质合金涂层的耐磨性和硬度进行了系统分析;利用XRD、SEM-EDS、摩擦磨损试验等手段，分析熔覆涂层的截面形貌、相组成、硬度及耐磨性能。研究结果表明，Fe901铁基硬质合金涂层显微组织主要是由奥氏体柱状晶和等轴枝晶组成，周围存在针状(Cr, Fe)7C3碳化析出物。涂层主要相包括α-Fe固溶体、(Cr, Fe)7C3混合碳化物和CrFeB硬质相。在高速激光熔覆扫描速度为3.0、4.2 m/min时，涂层平均硬度为767.80、829.97 HV0.3，是65 Mn弹簧钢基体(275.2 HV0.3)硬度的2.79、3.02倍。同时，涂层单位面积磨损量较无涂层磨损质量分别降低27.39%、32.78%，显著提升了耐磨性。本研究有效提高了Fe901铁基硬质合金涂层的硬度和耐磨性，并在改善铁基自磨刃的使用性能方面展现出应用潜力。

关键词:自磨刃涂层;高速激光熔覆;Fe901硬质合金粉末;硬度;耐磨性

Abstract:

To enhance the wear resistance of iron-based self-sharpening blades and improve the service life of agricultural machinery components, fiber-optic coaxial powder-fed laser cladding technology was employed on the surface of self-sharpening blade molds （65 Mn）. By adjusting the cladding scanning speed, a systematic analysis of the wear resistance and hardness of Fe901 hard alloy coatings was conducted. Techniques such as XRD, SEM-EDS, and friction and wear testing were used to analyze the cross-sectional morphology, phase composition, hardness, and wear resistance of the cladding coatings. The results showed that the microstructure of the Fe901 ironbased hard alloy coating consisted primarily of austenitic columnar and equiaxed dendrites, with needle-like （Cr, Fe）7C3 carbide precipitates observed around the matrix. The main phases of the coating included α-Fe solid solution，（Cr, Fe）7C3 mixed carbides, and CrFeB hard phases. At high scanning speeds of 3m/min and 4.2 m/min, the average hardness of the coating was 767.80 HV0.3 and 829.97 HV0.3, respectively, which were 2.79 and 3.02 times of the hardness of 65 Mn spring steel substrate （275.2 HV0.3）. Moreover, the wear volume per unit area of the coating was reduced by 27.39% and 32.78% compared with that of the uncoated substrate, significantly enhancing wear resistance. The research not only effectively improved the hardness and wear resistance of the Fe901iron-based hard alloy coating but also demonstrated significant potential for enhancing the performance of iron-based self-sharpening blades.

Key words:self-sharpening coating;high-speed laser cladding;Fe901 tungsten carbide powder;hardness;wear and corrosion