Heat-treating of metal alloys, particularly steel, to reduce brittleness and restore ductility. In tempering, steel is slowly heated to a temperature between 300 and 1,300 °F (150 and 700 °C), depending on desired properties, in an oil or salt bath and held for about two hours and then allowed to air cool. As steel is physically worked (e.g., rolling, wiredrawing, hammering), hardening takes place, and it grows progressively more brittle. Similarly, but more deliberately, heating and quenching increase hardness. Combined quench-and-temper heat-treating is applied at many different cooling rates, holding times, and temperatures and is a very important means of controlling the properties of steel.

This entry comes from Encyclopædia Britannica Concise.
For the full entry on tempering, visit Britannica.com.

Seen & Heard

What made you look up tempering? Please tell us what you were reading, watching or discussing that led you here.

Get Our Free Apps
Voice Search, Favorites,
Word of the Day, and More
Join Us on FB & Twitter
Get the Word of the Day and More