工艺参数对65Mn基熔覆Ni60a/SiC涂层的微观组织与耐磨性能影响

Effect of Process Parameters on Microstructure and Wear Resistance of 65Mn-based Cladding Ni60a/SiC Coating

为提高饲草揉切机中揉切刀片的耐磨性,采用激光熔覆技术在65Mn钢表面制备Ni60a/SiC复合粉末熔覆层。分析镀层的显微硬度、物相组成和摩擦磨损性能,以得到最佳激光熔覆工艺参数组合。结果表明,影响熔覆层硬度的工艺参数主次顺序依次是光斑直径,激光功率和扫描速度,熔覆层有新物相的析出,主要包括NiCr O_(3)与Cr_(3)Ni_(2)SiC等硬质相。最佳激光熔覆参数组合为激光功率2000 W,扫描速度400 mm/min和光斑直径3 mm,在此参数下的熔覆层显微硬度为870 HV_(0.1),并且熔覆层与基体呈现良好的冶金结合,在相同的磨损试验环境下,此熔覆层的磨损形式主要是磨粒磨损,磨损量为0.003 g,相比65Mn基体磨损参数,摩擦因数降低29%,磨痕深度降低83%,复合涂层的耐磨性明显增加,本研究在提高刀片的使用寿命方面具有较好的参考价值。

To improve the wear resistance of the kneading blade in the forage grass kneading and cutting machine,Ni60a/SiC composite powder cladding layer is prepared on 65Mn steel surface by laser cladding technology.The microhardness,phase composition,friction and wear properties of the coating are analyzed to obtain the best combination of laser cladding process parameters.The results show that the primary and secondary process parameters affect the hardness of clad layer are spot diameter,laser power,and scanning speed.The cladding layer has precipitation of new phase which mainly consists of hard phases such as NiCr O_(3)and Cr_(3)Ni_(2)SiC.The optimum combination of laser cladding parameters is laser power 2000 W,scanning speed 400 mm/min and spot diameter 3 mm.Under this parameter,the micro-hardness of the cladding layer is 870 HV_(0.1),which also exhibits efficient metallurgical bonding with the substrate.In the same wear test conditions,the wear form of the cladding layer is mainly abrasive wear and the amount of wear is 0.003 g.Compared with the wear parameters of the 65Mn based,the friction coefficient is reduced by 29%,the depth of wear scar depth is reduced by 83%,and the wear resistance of the composite coating increases significantly,This study has a good reference value in improving the service life of the blade.