Effects of Cr and V additions on the microstructure and properties of high-vanadium wear-resistant alloy steel

Abstract

The effects of chromium and vanadium additions on the microstructure, hardness and wear resistance of high-vanadium alloy steel (containing 5–10 wt-% V and 2–10 wt-% Cr) were studied by means of optical microscopy, scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS), Vickers hardness and Rockwell-hardness tester & M-200 ring block wear tester. Researching results showed that the solidification structure of high-vanadium wear-resistant alloy steel was mainly consisted α-Fe (martensite), vanadium carbide (VC), M3C and M7C3. Vanadium is mainly distributed over VC, and certain amount of vanadium exists in the matrix and M7C3 type eutectic carbide. Chromium is mainly distributed over the M7C3, and the matrix also contains a small quantity of chromium. It is found that the content of VC increases with the increase of vanadium content when carbon and chromium contents are constant. The change of micro- and macro-hardness was not obvious with the increase of vanadium content. The content of M7C3 type eutectic carbides increases gradually with the increase of chromium content when carbon and vanadium contents are constant. The micro- and macro-hardness increases with the increase of chromium content. The increase of vanadium content brings to the increase of wear resistance of alloy steel when carbon and chromium contents are constant. The change of chromium content had no obvious effect on wear resistance of high-vanadium alloy steel when carbon and vanadium contents. The increase of vanadium content brings to the increase of wear resistance of alloy steel when carbon and chromium contents are constant. The wear resistance of as-cast high-vanadium alloy steel is the best when the content of vanadium and chromium is 10 wt-% and 5 wt-% respectively.