What happens to the microstructure during tempering? How does the mechanical properties of the steel change due to tempering? How do you perform tempering? What type of steel is usually tempered?

Microstructure during tempering:

Tempering is a heat treatment process of heating the steel below its eutectoid temperature to make it less brittle or ductile. During tempering, moisturize structure changes to ferrite and cementite by which brittleness gets seduced. During tempering, Moisturize stage which is very stable and brittle behavior got changed to fertile and cementite which makes the steel more ductile and brittle. During tempering, the hardness also may get seduced. For tempering, the metal especially steel is heated to temperature but below its eutectoid temperature and then cooling is done usually in air. Tempering is done our steels which are alloyed with vanadium. Steels added with cobalt. Alloy steels with elements like manganese, nickel, silicon and aluminium are hardened.