Chemical Engineering - Chemical Engineering Basics - Discussion

Once we heat the iron base metal (steel etc) at very high temperature (840 C to 1000 C) and then suddenly cooled with water, it is referred as austenitizing while again we reheat it (450 C to 720 C) and sudden cool with water it is called as tempering.

Tempering, in metallurgy, process of improving the characteristics of a metal, especially steel, by heating it to a high temperature, though below the melting point, then cooling it, usually in air. The process has the effect of toughening by lessening brittleness and reducing internal stresses.

It improves the hardness and elasticity of (steel or other metal) by reheating and then cooling it.

Please explain tempering.