Programmable precision cooling of H13 tool steel during vacuum heat treatment overcomes the problems associated with conventional heat treatment.
Chromium hot-work tool steels have excellent resistance to high-temperature impact loading, resistance to softening during high-temperature exposure and resistance to thermal fatigue. These properties are achieved by the use of medium carbon content and relatively high concentrations of chromium and other strong carbide-forming elements. The medium carbon promotes toughness, and good high temperature strength is achieved by tempering at high temperatures to precipitate fine, stable dispersions of chromium and vanadium alloy carbides, which coarsen slowly in service. The high alloy content of these steels provides excellent hardenability and permits hardening of heavy sections with the use of the proper cooling rate. Many tools and dies are made of H13 hot-work tool steels, which is characterized by significant hardenability and good ductility, as well as by its resistance to drawing (softening), oxidation and, in particular, thermal fatigue.