Hardening and tempering of steel is a process designed to alter the mechanical properties of a part to fit its intended use.

Typically this involves heating the part to a certain temperature, at which point the crystal structure of the metal changes, ultimately leading to increased hardness and altered physical properties. It is then rapidly quenched in water, oil, liquid salt, or high pressure inert gas in order to prevent the new crystal structure reverting back to a softer state.

Rapid Cooling

This rapid cooling can make the material brittle, so hardening is usually followed by a lower temperature temper to relieve any heat induced stresses that may have built up during the hardening processes. Depending on the material and properties required a variety of tempers can be utilised, with higher temperatures resulting in lower hardness but improved ductility and toughness.

By utilising a vacuum furnace for hardening and tempering, parts are exposed to less oxygen and as such will have a clean finish after processing. Uniformity of heat distribution in vacuum also results in parts being more consistently through hardened with less distortion.

Overall, vacuum hardening and tempering provides clean, consistent and quality results with high dimensional stability.

Heat Treatment

MSL Heat Treatment originated as the heat treatment division of a major UK tool making company, and were one of the first to truly appreciate the benefits of vacuum heat treatment. As such we now have over 30 years of experience in the hardening and tempering of tool steels, sintered carbides, and high speed steels used by toolmakers and precision engineers across a variety of industries.

© MSL Heat Treatment Limited

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