Effect of boron concentration on microstructures and properties of Fe–B–C alloy steel

The solidification microstructure, types of eutectic borocarbides, heat treatment properties and wear resistance of steel withxwt% B–0.4 wt% C–6.0 wt% Cr–4.0 wt% Mo–1.0 wt% Al–1.0 wt% Si–1.0 wt% V–0.5 wt% Mn (x= 1.0, 2.0, 3.0) have been investigated in this present study. The results indicate that the as-cast Fe–B–C alloy steel consists of pearlite, ferrite, and borocarbides M2(B,C) (M = Fe, Cr, Mo, V, Mn). After quenching or quenching and tempering treatment, ferrite and pearlite transform into martensite. With the increase of boron content, the macrohardness of alloys increases obviously while wear loss decreases. Borocarbides with chromium addition have good toughness and no cracks are observed on worn surfaces. The wear mechanism changes from micro-cutting accompanied with the spalling of borocarbides to single micro-cutting with the boron content rising.