Solidification microstructures and mechanical properties of vertical centrifugal cast high speed steel

This study was undertaken to investigate the influence of Nb and V alloying elements and manufacturing conditions on the microstructural behaviour and mechanical characteristics of HSS (high speed steel) roll manufactured by a VCC (vertical centrifugal casting) process. In the Fe-2C-6Cr-1.5W-3Mo-4V alloy, the amount of MC carbide was increased and the the amount of M7C3 carbide decreased with an increase in V and Nb content. In steel containing 3%Nb, primary NbC carbide was formed within the cell in the matrix. The hardness of steel containing 6.5%V but no Nb was increased a little but when 9%V was added, the hardness decreased in the specimen owing to the soft ferritic matrix. The hardness of the matrix in steel containing 1.5%Nb increased, increased, but decreased for 3%Nb addition. In wear tests, wear loss decreased with increasing rotational wear speed.