Vacuum hardening
The vacuum hardening is a method in the tool steels (cold / hot work tool steels and high speed tool steels, conventional or powder metallurgy) can be heat treated industrially according to the state of the art. Alloyed, high-alloyed tool steels and martensitic stainless steels (e.g. 1.4112 X90CrMoV18) can be hardened and tempered up to a maximum temperature of 1300 ° C in these systems.
Alloyed and high-alloyed tool alloys are usually so-called air hardeners and do not require water or oil quenching for martensite formation as a hardening structure. Modern vacuum hardening systems have a gas overpressure cooling device with> 8 bar. Nitrogen is used as the quenching gas. Shortly before the quenching process, the compressed nitrogen is introduced into the annealing chamber of the vacuum furnace and cools the hardened material in a defined manner in the controllable gas flow. This "mild" gas flow usually leads to very small changes in shape and dimensions of the workpieces.
In addition, structurally necessary sharp edges or large cross-sectional transitions can be hardened without any problems, which inevitably leads to cracks and thus to rejects of the workpieces in the event of other cooling, for example during oil hardening.
The vacuum makes the vacuum hardening it can not react with gases in the kiln that retort and hardened material during the heating and holding phase. This is primarily intended to avoid edge decarburization and surface oxidation.
Modern vacuum furnaces reach temperatures of up to 1300 ° C, whereas multi-purpose chamber furnaces generally only reach around 1000 ° C.
Web links
- IBV vacuum furnace at RWTH Aachen University, chair for material applications in mechanical engineering. Retrieved December 6, 2013.