For the purpose of the development of a higher wear resistance roll produced by a centrifugal casting process, metallurgical studies were systematically carried out on relationships among alloying elements, casting conditions, microstructures and wear properties, using high-alloyed steels, such as a high speed tool steel. Results obtained are summarized, as follows: (1) The difference of the specific gravity between primary crystals and residual molten steel generates the segregation of VC to inner layer of a roll during centrifugal casting. (2) The addition of an appropriate amount of Nb makes the compound carbides of (V, Nb) C, which have the similar specific gravity to the residual molten Steel. (3) The uniform distribution of MC type granular carbides has been achieved in the roll of the 2 mass percent C - 6 mass percent -Nb type alloyed steel. (4) The increment of tough carbides enriched with C, Cr and Mo is effective to suppress an increase in rolling load and to improve a wear resistance. (5) The developed rolls have the wear resistance more than 4 times as high as conventional roll and have been satisfactorily used at the finishing stands of hot strip mills.
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