Effects of carbon and chromium additions on the wear resistance and surface roughness of cast high-speed steel rolls

The effects of carbon and chromium additions on the wear resistance and surface roughness of five high-speed steel (HSS) rolls manufactured by a centrifugal casting method were investigated in this study. High-temperature wear tests were conducted on these rolls to experimentally simulate the wear process during hot rolling. The wear-test results revealed that the wear resistance increased with increasing carbon content because of the increased total carbide fraction. In the HSS roll containing a smaller amount of chromium, the wear resistance was improved because it contained a number of very hard MC carbides. However, it showed a very rough roll surface because of the preferential removal of the matrix and the sticking of the rolled material to the roll surface during the wear process. Rolls containing a higher chromium content had very low surface roughness, because of the formation of a larger amount of M7C3 carbides of slightly lower hardness and homogeneous wear of the matrix and carbides. In order to improve wear resistance with consideration of surface roughness, the increase in the chromium content, i.e., the increase in the amount of M7C3 carbides, which can result in a low surface roughness, was suggested.