In order to optimize the process of tungsten carbide (WC)-reinforced Co50 cermet composite coating by laser cladding, Co-based coatings with 40 wt% WC were deposited on the surface of cone bit 15MnNi4Mo steel by 4 kW fiber laser. A single-factor experiment was designed to study the variation of the geometrical size, dilution rate and hardness of cladding layers with the change of various factors. Then, an orthogonal experiment was designed to study the optimal parameters for the laser cladding process by taking the hardness and dilution rate of the coatings as comprehensive indexes. Based on the results of the above experiments, the mathematical model of the relationship between the geometrical size of the cladding layers with the process parameters was established by regression analysis. In addition, the three-dimensional structure and microstructure of the coatings were analyzed by optical microscopy (OM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results revealed that with the increase of the laser power, the width of the cladding layer, the depth of the molten pool and the dilution rate gradually increased, while the coating height remained basically unchanged. Additionally, with the increase of the scanning speed, the coating height and the molten pool depth were relatively greatly reduced, while the coating width decreased little. Furthermore, with the increase of the powder feeding rate, the width of the cladding layer, the molten pool depth and the dilution rate gradually decreased, while the coating height gradually increased. The optimal process parameters are as follows: laser power of 2.4 kW, scanning speed of 7 mm/s, and powder feeding rate of 0.5 g/s. The mathematical model established by regression analysis fitted the width of the cladding layer best, and the minimum relative error was only 0.023%. The microstructure showed that metallurgical bonding was achieved between the coatings and substrates. Also, the coatings were compact and free of defects such as cracks and pores.

为了优化激光熔覆碳化钨（Co）增强Co50金属陶瓷复合涂层的工艺，采用4 kW光纤激光在锥度15MnNi4Mo钢的表面沉积了WC含量为40 wt％的Co基涂层。设计了单因素实验，研究了随着各种因素的变化，包层的几何尺寸，稀释率和硬度的变化。然后，以涂层的硬度和稀释率为综合指标，设计了正交试验，研究了激光熔覆工艺的最佳参数。根据以上实验结果，通过回归分析建立了熔覆层几何尺寸与工艺参数之间关系的数学模型。此外，通过光学显微镜（OM），扫描电子显微镜（SEM）和能量色散X射线能谱（EDS）对涂层的三维结构和微观结构进行了分析。结果表明，随着激光功率的增加，熔覆层的宽度，熔池深度和稀释率逐渐增加，而涂层高度基本保持不变。另外，随着扫描速度的增加，涂层高度和熔池深度相对减小，而涂层宽度几乎没有减小。此外，随着送粉速度的增加，熔覆层的宽度，熔池深度和稀释率逐渐减小，而涂层高度逐渐增大。最佳工艺参数如下：激光功率为2。4 kW，扫描速度为7 mm / s，送粉速度为0.5 g / s。通过回归分析建立的数学模型最适合包层的宽度，最小相对误差仅为0.023％。显微组织表明，在涂层和基体之间实现了冶金结合。而且，涂层是致密的并且没有诸如裂缝和孔的缺陷。