NADCAP certified; Syracuse Heat Treating has two Vacuums for the hardening of (Tool, Stainless, High Speed, Powdered, Cobalt, and Nickel) steels. These vacuums also have the ability to bright temper these steels along with precipitation aging of (PH, Mo, Maraging) steels when required to meet customer's bright requirements. When bright tempering isn't required for alloys at higher temperatures we have eighteen Tempering Furnaces page. Vacuum hardening is a typical heat treating process for a variety of carbon and alloy steels.
Vacuum hardening is the process of heat treating these alloys in a vacuum atmosphere (1 Micron or less) or partial pressure atmosphere (100-500 microns) to a specific temperature and then gas quenching (nitrogen or argon). Gas quenching can be performed from -5 psi to +15 psi. This process changes the material's structure partially or completely into a martensitic structure. This structure will have the highest hardness (HRC) after quench but will be unstable and require tempering. The alloy must undergo tempering treatment after hardening in order to obtain high ductility and toughness.
Any temperature can be used for tempering, but it is the balance of hardness, strength, and toughness required in service that determines the final tempering temperature. Double tempering is sometimes performed to ensure completion of the tempering reaction and to promote stability of the resulting microstructure.