Failure Analysis and Remanufacturing of Construction Machinery Shafts by HVOF Technique

In this work, a scrapped cross shaft which was assembled at the differential of ZL50C loader was analyzed by scanning electron microscopy (SEM) to examine the failure mechanism and was remanufactured by HVOF with ~500μm thickness WC-12Co coatings on it. The microstructure, phase compositions and properties of deposited WC-12Co coatings were investigated through optical microscope (OM), SEM, X-ray diffraction (XRD), microhardness tester and tensile testing machine. The results show that the 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 and W2C. The microhardness of the coating was approximated to 1100 HV0.1 and the bonding strength was higher than 63.7 MPa. It can be concluded that WC-12Co coating sprayed by HVOF was suitable for the remanufacturing of shaft parts.