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激光熔覆Stellite6–60WC复合涂层工艺及高温耐磨性

Laser Cladding Stellite6−60WC Composite Coating Process and High- temperature Wear Resistance

  • 摘要: 以Co基Stellite6合金与陶瓷(WC)为熔覆粉末,采用激光熔覆技术在沉没辊316L基体添加质量分数为60%的WC粉末,制备Stellite6−60WC熔覆层,分析激光功率、扫描速度、送粉量等工艺因素对熔覆层形貌的影响,确定最优熔覆工艺参数;且对复合涂层的物相、硬度和耐磨性进行研究,探讨熔覆层高温耐磨性能改善的机理。结果表明:激光功率1.5 kW、扫描速度300 mm/min、送粉速率18.8 g/min时,熔覆层表面质量较好,涂层与基体形成良好的冶金结合,表面无裂纹和孔洞;熔覆层的相组成主要为γ−Co,M7C3,M23C6(M=Co,Cr,Fe),W2C等硬质相,利于提高熔覆层的硬度,硬度可达736.2 HV,是基体的3.5倍;熔覆层的高温耐磨性优于316L基体,比基体提高了6.1倍,主要是熔覆层多种硬质强化相及未熔的WC颗粒所致。

     

    Abstract: Taking Co-based Stellite6 alloy powder and WC ceramic powder as cladding powder,a Stellite6−60WC cladding layer was prepared by adding 60% WC powder to the 316L substrate of the sinking roller using laser cladding technology. The effects of process factors such as laser power, scanning speed and powder feeding amount on the morphology of the cladding layer were studied to determine the optimal cladding process parameters, The phase and hardness and wear resistance were studied to explore the mechanism of improving the high-temperature wear resistance of the cladding layer. The results show that when the laser power is 1.5 kW, the scanning speed is 300 mm/min, and the powder feeding rate is 18.8 g/min, the surface quality of the cladding layer is good.The metallurgical bonding between the coating and the substrate, and the surface of the coating is free of cracks and holes. The phase composition of the cladding layer is mainly composed of hard phases such as γ−Co, M7C3, M23C6 (M=Co, Cr, Fe), W2C and other hard phases, which is beneficial for improving the hardness of the cladding layer. The hardness can reach 736.2 HV, which is 3.5 times that of the substrate. The high-temperature wear resistance of the cladding layer is better than that of the 316L substrate, which is 6.1 times higher than that of the substrate, mainly because of the various hard strengthening phases and unmelted WC particles in the cladding layer.

     

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