Improvement in microstructure and wear-resistance of high chromium cast iron/medium carbon steel bimetal with high vanadium

Abstract

In the present study, a high chromium cast iron (HCCI) with high content of vanadium (15 wt.%) as the wear resistance layer was fabricated on the medium carbon steel (MCS) substrate by laser cladding process. The effect of high vanadium addition on microstructure, phase, hardness and wear properties of bimetal were investigated. The results show that the microstructure of HCCI layer was significantly improved and refined with addition of high vanadium. No defect such as microcracks and unbonded regions was observed on the interface of the bimetal. The x-ray diffraction revealed that the HCCI (15 wt.% V) layer consists of α-Fe matrix, (Cr, Fe)7C3 and VC carbides. The SEM images shown that round-like VC particles uniformly distributed on the α-Fe matrix and (Cr, Fe)7C3 are of rod-like with distributed on grain boundary, such micromorphology makes it have higher hardness (883HV) and excellent wear resistance than HCCI layer without vanadium addition.