What is Post Hardening?
In some cases, where heavy forming forces are present, or difficult to form material are worked (e.g. stainless steels), TD treated cold work tool steels are re-hardened i.e. post TD hardened, in a vacuum furnace. This does increase the substrate hardness by 1 or 2 Rockwell points and provides better support for the coating. High speed steels in most cases require post hardening to obtain maximum working hardness (61-64 HRC).
