面向工程机械绿色再制造的超音速火焰喷涂碳化钨硬面涂层的性能

绿色再制造工程在上世纪八十年代国际上兴起,并成为发展最快的新型研究领域和新兴产业之一。本文利用超音速火焰喷涂技术制备WC-12Co涂层,探讨了该涂层在磨损失效的ZL50C型装载机驱动桥差速器的十字轴领域的应用可能性。通过光学显微镜、扫描电子显微镜、X射线、显微硬度计和拉伸测试对所制备的涂层进行了评定,以硬度为目标,所获的优化工艺参数为:丙烷压力为0.45MPa,流量为17L/min,氧气压力为0.65MPa,流量为167L/min,喷涂距离为275mm。通过优化工艺参数制备的WC-12Co涂层致密,孔隙率低于1%,涂层由WC、Co和部分分解的W2C等组成;涂层的显微硬度为1100HV0.1左右,结合强度超过63.7MPa。通过在十字轴的表面制备了厚度约500μm的WC-12Co涂层,恢复了轴的直径尺寸,并大大改善了十字轴的耐磨性,该类涂层适用于十字轴等耐磨工程机械零部件的再制造。

The Properties of HVOF Sprayed WC-12Co Hard Coating for the Green Remanufacturing on Construction Machinery

The green remanufacturing engineering has attracted great interests in the world since 1980s, and became one of the fastest growing novel research fields and new industry. The WC-12Co coating was deposited by HVOF technique and the possibility of its application on worn cross shaft of differential part of ZL50C-loader＇ s driving axle was discussed in this paper. The HVOF sprayed coatings were evaluated by optical microscope, SEM, X-ray, micro hardness tester and tensile test. Taking the hardness of coating as evaluation indicator, the optimized process parameters obtained are： the pressure of propane was 0.45MPa, the flow of propane was 17 L/min, the pressure of oxygen was 0.65MPa, the flow of oxygen was 167 L/ min, and spraying distance was 275 mm. The sprayed coatings were very dense, and their porosities were lower than 1%. According to the X-ray Diffraction （XRD） analysis, the phase compositions of the sprayed coatings consisted of WC, Co, W2C. The micro hardness of the coating was about 1100HV0.1 and bonding strength was over 63.7MPa. The cross shaft diameter dimension was restored by HVOF sprayed 500 μm thickness WC-Co coating and its wear-resistance was greatly improved It is concluded that WC-12Co coating sprayed by HVOF was suitable for the remanufacturing of wear-resistant construction machinery parts and components, such as cross shaft.