Heat treatment

The term heat treatment refers to a group of production processes in which a material (metal, ceramic, plastic) undergoes one or more treatment stages involving temperature changes or temperature sequences to give it specific properties. Heat treatment can release substances (nitrogen, carbon) into, or absorb them from, the environment.

During heat treatment, the Material is heated and cooled according to a defined time-temperature regime. This can specifically adjust technological properties such as Microstructure, hardness, Strength and Toughness.

A distinction is made between processes that cause complete structural transformation (such as Hardening) and processes that simply change the surface (e.g. surface hardening). A further distinction is made between thermal processes (such as Annealing and hardening) and thermochemical processes (including carburising, nitriding, boronising and case hardening).

Depending on the microstructures or properties to be achieved, the processes are divided into the following production options:

• Coarse grain annealing
• Soft annealing
• Recrystallisation annealing
• Stress-relief annealing
• Solution annealing

The expected stress is also factored in, for example in the case of:

• Hardening
• Precipitation hardening
• Hardening and tempering
• Surface hardening
• Nitriding
• Carburising