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螺杆钻具转子表面Ni基WC陶瓷涂层组织及性能研究

Study on microstructures and properties of Ni-based WC ceramic coating on screw drilling rotor surface

  • 摘要: 为了提高螺杆钻具转子的耐磨损性能和耐腐蚀性能,采用激光熔覆技术在45#钢转子材料表面制备了Ni+50%WC熔覆层,利用扫描电镜分析熔覆层组织特征和WC陶瓷颗粒形态,并利用硬度计、材料性能分析仪和电化学测试系统检测表面性能,评价添加50%WC颗粒对Ni基合金层显微硬度分布、耐磨性能以及耐腐蚀性能的影响。结果表明,Ni+50%WC熔覆层厚度约为1.35 mm,冶金结合且稀释率低,熔覆层内WC颗粒分布均匀,还伴随着多边形碳化物和晶界网状碳化物析出;得益于固溶强化和析出强化共同作用,Ni+50%WC熔覆层硬度达到577.2 HV0.2;尽管随着转速的增加,失重量略有增大,但Ni+50%WC熔覆层的磨损失重量远低于45#钢,仅为后者的3.5%,且磨痕宽度明显减小,磨损机制转变为磨粒磨损;在3.5%NaCl溶液中的耐蚀性测试结果证实,Ni+50%WC熔覆层的自腐蚀电流密度仅为0.034603 μA/cm2,是45#钢的0.565%。可见激光熔覆Ni+50%WC复合层能显著提升45#钢耐磨性和耐蚀性能,对于延长螺杆钻具转子的使用寿命及降低维护成本具有重要的意义。

     

    Abstract: In order to improve the wear resistance and corrosion resistance of screw drill rotors, a Ni+50% WC cladding layer was fabricated on the surface of 45# steel using laser cladding technology. The microstructure and morphology of WC ceramic particles in the cladding layer were analyzed using scanning electron microscopy. Surface properties were tested using a hardness tester, mechanical property analyzer, and an electrochemical testing system to assess the effects of adding 50% WC particles on the microhardness distribution, wear resistance, and corrosion resistance of the Ni-based alloy layer. The results showed that the Ni+50% WC cladding layer had a thickness of approximately 1.35 mm, and featured metallurgical bonding with a low dilution rate. The WC particles in the cladding layer were uniformly distributed, along with the precipitation of polygonal carbides and grain boundary reticular carbides. Due to the combined effect of solid solution strengthening and precipitation strengthening, the hardness of the Ni+50% WC cladding layer reached 577.2 HV0.2. Although the weight loss slightly increased with increasing rotational speed, the wear loss of the Ni+50%WC cladding layer remained significantly lower than that of 45# steel, accounting for only 3.5% of the latter. The wear scar width was also considerably reduced, and the wear mechanism transitioned to abrasive wear. Corrosion resistance tests in a 3.5% NaCl solution confirmed that the self-corrosion current density of the Ni+50% WC cladding layer was only 0.034603 μA/cm2, which was 0.565% that of 45# steel. Therefore, the laser-clad Ni+50%WC composite layer can significantly enhance the wear and corrosion resistance of 45# steel, which is of great significance for prolonging the service life of screw drill rotors and reducing maintenance costs.

     

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