Mechanical Properties of WC-8Co Wear- Resistant Coating on Pump Impellers Surface by Electro- Spark

摘要:

为了增强水泵过流部件表面抗气蚀、磨蚀的能力，采用电火花表面熔覆技术，结合独创螺旋往复式加工方法，在水泵叶轮常用材料1Cr18Ni9Ti表面制备了WC-8Co熔覆层。结合扫描电镜、显微硬度测量仪和摩擦磨损试验机分析了熔覆层的表面形貌、显微组织、显微硬度和耐磨性能。结果表明，熔覆层组织均匀、连续、致密，没有明显的裂纹和孔洞，熔覆层和基体材料没有明显的分界线，呈冶金结合；熔覆层的显微硬度HV0.3最大值达到18 920 MPa，平均硬度值为17 950 MPa，比水泵基体材料硬度（2600 MPa）提高了近6倍； 熔覆层的耐磨性是水泵基体材料的3.75倍，熔覆层的磨损机理主要是黏着磨损和磨粒磨损。

Abstract:

A WC-8Co cladding coating was prepared on the surface of 1Cr18Ni9Ti stainless steel by electro-spark cladding technique combined with an original spiral reciprocating processing method, to improve the capacity of anti-cavitation, anti-abrasion on the surface of flow parts of the pumps. The morphology, the microstructure, the microhardness and the wear resistance of the cladding coating were investigated by means of scanning electron microscopy (SEM), microhardness test and friction and wear test. The results indicate that the cladding coating is uniform, continuous, compact, with no obvious cracks and holes, and there is no clear dividing line and a metallurgical bonding is presented between cladding coating and substrate material. The highest microhardness HV0.3 is 18 920 MPa and the average hardness HV0.3 of the cladding coating is 17 950 MPa, which is about 6 times higher than that of the substrate (2600 MPa). The wear resistance of the cladding coating is 3.75 times of the substrate and the main wear mechanism is adhesive and abrasive wear.