Microstructure and properties of modified as‐cast hypereutectic high chromium cast iron

Abstract

The present work studied the effects of different modification treatments on the microstructure and mechanical properties of hypereutectic high chromium cast iron containing about 35 wt% chromium and 4.0 wt% carbon. It was found that the primary carbides in the hypereutectic high chromium cast iron were all refined to different levels after different modification treatments. Among them, the best result was obtained by adding 0.6 wt % rare earth magnesium, and its average carbide diameters was 43 μm, which is almost half of the unmodified specimen. After modification, the mechanical properties have been improved, and the refinement of primary carbides can greatly improve its impact toughness. The impact toughness of the specimen modified by adding 0.6 wt % rare earth magnesium was the largest, reaching 7.0 J cm−2, and the impact toughness of un‐modification specimen was the worst, only 4.5 J cm−2. The refining of primary carbides does not have much effect on the hardness. The hardness of the sample with 0.6 wt % rare earth magnesium and 0.3 wt % TiBAl is the highest, and its value is 58.0 HRC. The wear resistance increases with the refinement of primary carbides.