The Microstructures and Hardness Analysis of a New Hypereutectoid Mn-Cr-Mo-V Steel

Abstract

The results of a microstructure and hardness investigations of a new hypereutectoid Mn-Cr-Mo-V steel, imitating by its chemical composition tool steels, are presented in the paper. The microstructure as well hardness changes, caused by austenitising and tempering temperatures were assessed, for samples quenched and sub-quenched in liquid nitrogen, directly after the quenching treatment. Additionally, the influence of the tempering temperature on the volume fraction of the retained austenite was estimated. New hypereutectoid steel, after an appropriate heat treatment obtained the relevant hardness of the tools used in the cold and hot working proces. It was indicated that the steel hardness increases with the increases of the austenitising temperature. At 800ºC the hardness of the quenched samples were equal 895HV, and for the sub-quenched samples 937HV. The maximum hardness, after tempering (746HV), was found at a temperature of 520ºC. It will be possible, in future, to apply this obtained investigation results in designing chemical compositions and microstructures of the new hypereutectoid alloyed steels of properties required by their users.