Some mold steel such as H13, 2316, S136, etc. can be done vacuum quenching harding treatment to make the hardness 48-52HRC. In order to get the long mold life.
The hardening treatment need to be done after mold rough tooling before detail tooling. Due to after treatment, the steel hardness is very high, so the tooling time is long. This is the reason that mould made with steel which hardness required 48 to 52hrc, the mould test time is longer than other steel mould (for example P20 steel).