Types of Heat Treatment:
Quenching and Tempering: In the austenitizing and quenching process, the steel is evenly heated to a temperature above the critical range and rapidly quenched to achieve the requested structure. It is then tempered for the requested mechanical properties. Thanks to this process, certain levels of strength and hardness are achieved.
Normalizing: In the normalizing process, the steel is heated evenly to a temperature above the critical range, then cooled to room temperature in air. This process provides the product with homogeneity in terms of hardness and structure by providing recrystallization and rearrangement of the grain structure. This type of heat treatment is preferred for oil and gas drilling and completion applications.
Annealing: Annealing is the process of heating steel evenly to a temperature within or above the critical range and cooling to a temperature below the critical range at a controlled rate. This process is generally applied to produce a specific microstructure designed for good machinability and ductility. Annealing is also done to relieve stress, provide softness, and change hardness or other mechanical properties.
Spheroidizing Annealing: In Spheroidizing Annealing, a long heating time is used to produce the best carbide microstructures for machinability and downstream processing. This heat treatment method is applied especially in bearing, industrial and mining parts.
Stress Relieving: Stress Relieving helps to minimize distortion for machining. It also reduces the risk of weld-related cracks.
Tempering: The purpose of tempering is to increase the toughness of the steel and reduce the stresses. After quenching, the martensitic structure has a relatively low toughness with residual stresses. If the steel is reheated to a temperature between 160 - 650 ° C for 1 - 2 hours, the toughness can be increased and the stresses decreased, depending on the steel grade. Tempering will reduce the risk of cracking. Gears and shafts take advantage of these features.