WC-Co硬质合金涂层的激光熔覆工艺研究

Study on Laser Cladding Process of WC-Co Carbide Coating

通过混合不同粒径、不同比例WC颗粒的纯Co粉末,在不同工艺装备和参数下进行激光熔覆试验及结果检测,证明大芯径、大光斑的半导体激光更适用于金属基硬质合金熔覆。通过降低光斑能量集中度,降低输入功率,减小热输入,增大WC颗粒粒径,降低WC颗粒的热敏感度,能有效抑制WC熔解和分解,减小熔覆层气孔数量和尺寸。采用基材预热或全Ar气保护可降低熔覆层的开裂倾向。全Ar气保护条件下,采用输入功率800 W、扫描速度4 mm/s、送粉率11 Hz参数组,或基材预热400~450℃条件下,采用输入功率800 W、扫描速度7 mm/s、送粉率11 Hz参数组,均获得了WC质量分数60%、无开裂、低气孔率的大面积WC-Co激光熔覆硬质合金涂层。

In this paper, through the laser cladding experiments of pure Co powder mixed with WC particles of different sizes and proportions under different technological equipment and parameters and cladding effect detection, it proved that the semiconductor laser with large fiber core diameter and large light spot is more suitable for metal based cemented carbide cladding. By reducing the energy concentration of the spot and reducing the input power to reduce the heat input, and increasing the WC particle size to reduce the thermal sensitivity of the WC particles, which can effectively inhibit the dissolution and decomposition of WC, and reduce the number and size of pores in the cladding layer. The cracking tendency of the cladding layer can be reduced by substrate preheating or full Ar protection. A large area of laser cladding WC-Co cemented carbide coating with a WC mass fraction of 60%, no cracking, and low porosity can be obtained under full Ar protection conditions, using input power 800 W, scanning speed 4 mm/s, powder feeding rate 11 Hz, or under substrate preheating 400-450 ℃ conditions, using input power 800 W, scanning speed 7 mm/s, powder feeding rate 11 Hz.