Microstructure and abrasive wear properties of high-vanadium-chromium wear resistant alloy

Abstract

To enhance the wear resistance of high chromium cast iron (HCCI, Cr26), a new wear resistant alloy with high vanadium and chromium contents (HCCI-V, 15Cr5V4MoSiMn) was designed and prepared by sand mold casting. The microstructure and the phase composition were analyzed by SEM, EDS and XRD, and the abrasive wear property was tested compared with HCCI. Results show that the new wear resistant alloy is characterized by multi-scale and multi-type carbides distributed in a metal matrix composed of martensite and retained austensite. The carbides include VC, M7C3, M2C and M23C6 (M stands for (Cr, Fe)), with dimensions ranging from tens of nanometers to tens of micrometers. The hardness and impact toughness of HCCI-V are 65 ± 0.2 HRC and 10 ± 0.12 J cm−2, respectively, far higher than that of HCCI (57 ± 0.2 HRC, 8 ± 0.12 J cm−2). When the abrasive particle size and load are 6.5 μm and 1.41 MPa respectively, the wear weight loss of HCCI and HCCI-V are 5.6 ± 0.1 mg and 0.8 ± 0.1 mg respectively, and the relative wear resistance of HCCI-V is 7. The excellent wear resistance of HCCI-V is attributed to the multi-scale carbides. The micro-scale carbides resist scratch, and the nano-scale carbides strengthens matrix. The multi-scale carbides can work collaboratively to resist abrasive wear efficiently.