Effects of Vanadium Content on As-cast Microstructure and Mechanical Properties of Iron Base Wear-resistant Alloy

On the basis of traditional high-speed steel composition, an iron base wear-resistant alloy was designed to prepare rolls. The effects of vanadium contents (0wt%, 0.5wt%, 1.0wt% and 1.5wt%) on the as-cast microstructure and mechanical properties of the new iron base wear-resistant alloy were studied. The results show that the as-cast structure of iron base wear-resistant alloy with different vanadium contents is composed of pearlite, martensite, retained austenite and eutectic carbide distributed along the grain boundary. With the increase of vanadium content, the eutectic carbide gradually changes from fishbone M₆C to lamellar M₂C and granular MC. More importantly, when the vanadium content is 1.0wt%, the hardness reaches the maximum value of 64.08 HRC, which is 11.48% higher than that of high-speed steel without vanadium (57.48 HRC). When the vanadium content is 1.5wt%, the impact toughness reaches the maximum value of 11.82 J/cm², which is 17.96% higher than that of high-speed steel without vanadium (10.02 J/cm²). In addition, the fracture mode of iron base wear-resistant alloy with different vanadium contents is quasi cleavage fracture. Compared with the iron base wear-resistant alloy without vanadium, the cleavage like plane on the fracture surface of the iron base wear-resistant alloy with 1.5wt% addition becomes smaller, and there is a certain amount of spherical MC type carbide on the fracture surface, which has less cutting effect on the matrix, and the impact property is greatly improved.