Tempering

Heat Treatment

Определение

A heat treatment applied after quenching in which hardened steel is reheated to a temperature below the lower critical temperature (Ac1) and then cooled, to reduce brittleness and internal stresses while retaining most of the hardness.

Подробное объяснение

Tempering transforms brittle martensite into tempered martensite by allowing carbon to partially diffuse out of the supersaturated lattice and precipitate as fine carbides. Higher tempering temperatures decrease hardness but increase toughness and ductility; structural steels are often tempered at 550–650°C to achieve a good balance. The quench-and-temper (Q&T) process is the basis of high-strength structural steel production.