What is Oil Hardening Tool Steel?
Oil hardening tool steel contains carbon and other alloying elements that can be hardened at a relatively low heat and then quenched (cooled) in oil. (Oil should be warm and moving to draw heat away from the part to avoid cracking and case hardening. Do not leave the material in oil until it is cold; remove parts from quenching oil while still warm, and then transfer them to a tempering furnace.