Formation of microstructure during sub-zero treatment of Cr-V ledeburitic steel
Despite the fact that the sub-zero treatment has widely been employed in various industrial branches more than 100 years, metallurgical principles of microstructural alterations was discovered only over past several years. Many experimental works have been done in order to describe what happens in the microstructures of ball bearing steels, chromium cold work tool steels, and in chromium-vanadium ledeburitic steels when they are subjected to the treatment within a temperature range 4 – 273 K and for different durations. The obtained results infer that the changes in microstructure and thus in mechanical properties depend not only on the treatment regime used, but they are closely related to the steel chemistry. The current paper is focused to the description of what happens when 7%Cr – 6%V ledeburitic steel is subjected to sub-zero treatments at different temperature-time schedules.