铁基激光熔覆层的微观结构和摩擦磨损性能研究

选择市售的3种铁基粉末为原料(X₁~X₃),利用激光熔覆技术在45钢表面制备了3种熔覆层,研究了熔覆层微观结构和摩擦磨损性能,并选择电镀硬铬作为对比。结果表明,3种熔覆层组织致密,由α'马氏体、残余奥氏体和δ铁素体组成,其中X₁粉末熔覆层树枝晶更发达,晶粒更细小; X1粉末熔覆层硬度明显高于X₂、X₃粉末熔覆层,但低于电镀硬铬; 此外,3种熔覆层干摩擦系数虽与电镀硬铬接近,但耐磨性均明显优于电镀硬铬,且与其硬度呈正相关关系,磨损机理以磨粒磨损和疲劳磨损为主。

Microstructure,Friction and Wear Properties of Iron-Based Laser Cladding Coating

With three kinds of iron-based powders (X₁~X₃) as raw materials, three kinds of cladding layers were coated on 45 steel by laser cladding technology. The microstructure, friction and wear properties of the cladding layers were investigated, with which electroplated hard chromium layer was selected to compare. The results show that three kinds of cladding layers all have a compact microstructure and are mainly composed of α'-martensite, austenite and δ-ferrite phases. X₁ powder cladding layer has more developed dendrites and finer grains. The hardness of X₁ cladding layer is significantly higher than X₂ and X₃ cladding layers, but lower than electroplated hard chrome layer. In addition, three kinds of cladding layers have the dry friction coefficient closer to electroplated hard chromium plating, but have a better wear resistance, which has a positive correlation with the hardness. The mechanisms of wear are mainly abrasive wear and fatigue wear.