42CrMo基体激光熔覆质量优化的试验与数值仿真研究

    Experiment on Quality Optimization of Laser Cladding on 42CrMo Substrate and Numerical Simulation

    • 摘要: 采用同轴送粉的激光熔覆技术在42CrMo基体上制备单层多道熔覆层试件,通过16组正交试验和极差分析,研究搭接率、激光功率和扫描速率3个激光参数相互作用对TiC/H13复合熔覆层的宏观质量、微观结构以及力学性能的影响,寻找参数的最优搭配。采用Simufact Welding软件对熔覆过程进行仿真,研究基体预热对熔覆层裂纹数量的影响。对熔覆过程进行数值仿真。结果表明:搭接率对熔覆层宏观质量影响最大,激光功率和扫描速率对宏观质量的影响都较小;16组试件熔覆层的显微硬度差距不大,在800~950 HV,相对基体显微硬度560 HV提升明显;激光功率和扫描速率相互作用对TiC颗粒溶解影响很大,说明增强相在熔覆层中均匀分布,有利于熔覆层显微硬度的提升。激光作用在基体上对后面的熔覆产生预热效果,熔覆层中的热应力明显变小,验证了基体预热有利于抑制裂纹的产生。

       

      Abstract: Single-layer and multi-channel cladding layer specimens were prepared on 42CrMo substrate by coaxial powder feeding laser cladding technology.The effects of three laser parameters, including overlap ratio, laser power and scanning speed, on the macroscopic quality, microstructure and mechanical properties of TiC/H13 composite layer were investigated with 16 groups of orthogonal experiment and range analysis, tried to find optimal parameter collocation.The simulation of the laser cladding process was carried out by Simufact Welding software to study the influence of the preheating of the substrate on the number of cracks in the cladding layer.The cladding process was simulated numerically.The results show that the overlap ratio has the greatest influence on the macroscopic quality of the cladding layer, while the laser power and scanning speed has little influence on it.The microhardness of the cladding layer of the 16 groups of specimens is not very different which between 800 HV and 950 HV.It has a great improvement compared with the 560 HV of the substrate.The interaction of laser power and scanning speed controlled the dissolution of TiC particles which indicate that the uniform distribution of TiC in the cladding layer is beneficial to improve the microhardness of the cladding layer.Through the numerical simulation, it is found that the laser action on the substrate would have a preheating effect on the subsequent cladding, and the thermal stress of the cladding layer significantly reduces, which can verify that the preheating of the substrate is beneficial to suppress the generation of cracks.

       

    /

    返回文章
    返回