Effect of casting thickness on microstructure, mechanical properties and abrasion resistance of Fe-B cast alloy

Effects of casting thickness on microstructure, mechanical properties and abrasion resistance of Fe-B cast alloy have been systematically investigated. The results show that the microstructures of as-cast Fe-B alloy mainly consist of martensite, pearlite and M₂B; with increasing of casting thickness, the V_m/V_p (where V_p shows volume fraction of pearlite and V_m shows volume fraction of martensite) decreases, while the morphology, composition and V_b (volume fraction of boride) of Fe-B alloy are nearly unchanged. Moreover, with increasing of casting thickness, the microhardnesses of martensite, pearlite and M₂B have little change, while the bulk hardness of as-cast Fe-B alloy decreases in a line relationship (y = −0.33x+64.67) owning to the decreasing of V_m/V_p. During wear process, the predominant wear mechanism of as-cast Fe-B alloy may change from microcutting to microploughing with decreasing V_m/V_p, resulting in the more and more boride being crushed by F_⊥. As a result, the wear weight loss of Fe-B increases (i.e. the abrasion resistance decreases) with the decreasing of V_m/V_p, indicating that the V_m/V_p has positive influence on abrasion resistance of Fe-B cast alloy.