面向盾构机密封跑道修复的激光熔覆Fe基涂层制备工艺

为探究激光熔覆再制造修复工艺对盾构机密封跑道磨痕的修复效果,采用送粉式激光熔覆工艺在42CrMo钢基体表面制备了Fe55铁基自熔合金涂层。基于L₁₆(4³)正交试验探究了激光功率、熔覆速率和搭接率对涂层表面形貌、横截面特征参数、稀释率、显微组织、硬度的影响规律和作用机理。极差分析表明,稀释率随激光功率和熔覆速率的增加均呈上升趋势,其中激光功率对涂层硬度影响最大,最大涂层硬度约为基体硬度的2.15倍。Fe55涂层的摩擦因数较基体明显降低,涂层耐磨性优良,其磨损体积较基体降低1.09×10^-2 mm³,主要磨损机制为磨粒磨损和疲劳磨损。

Preparation technology of laser clad Fe-based coating for shield sealing runway repair

To explore the effect of laser cladding remanufacturing on repair of the wear scar of the shield machine sealing runway, the Fe-based self-fusible alloy coating (Fe55) was prepared on 42CrMo steel substrate by powder feeding laser cladding process. Based on the L₁₆(4³) orthogonal experiment, the effects of laser power, cladding rate and over lap rate on surface morphology, cross section characteristic parameters, dilution rate, microstructure and hardness of the coating were investigated. The results of range analysis show that the dilution rate increases with the increase of laser power and cladding rate, among which the laser power has the greatest influence on coating hardness, and the maximum coating hardness is about 2.16 times of the matrix hardness. Fe-based coating can significantly reduce the friction coefficient of the matrix and has excellent wear resistance. Its wear volume is 1.09×10^-2 mm³ lower than that of the matrix. The main wear mechanism is abrasive wear and fatigue wear.