The act by which something is tempered.
Austempering is heat treatment that is applied to ferrous metals, most notably steel and ductile iron. In steel it produces a bainite microstructure whereas in cast irons it produces a structure of acicular ferrite and high carbon, stabilized austenite known as ausferrite.
The process of giving the requisite degree of hardness or softness to a substance, as iron and steel; especially, the process of giving to steel the degree of hardness required for various purposes, consisting usually in first plunging the article, when heated to redness, in cold water or other liquid, to give an excess of hardness, and then reheating it gradually until the hardness is reduced or drawn down to the degree required, as indicated by the color produced on a polished portion, or by the burning of oil.
hardening something by heat treatment
moderating by making more temperate