Heat Treatments Applied to Steels

Heat treatment is the process of heating and cooling at high temperatures applied to solid metals and alloys in order to give them properties they do not have. The aim of heat treatment is to improve mechanical properties. Heat treatment involves heating metals or alloys, keeping them at the heated temperature for a certain period of time, and cooling them to room temperature. Along with desired changes, undesirable changes may also occur during heat treatment. The purposes of heat treatments can be listed as follows; Relieving internal stresses of metals and alloys Facilitating machining work Eliminating deteriorations in the structure due to cold and hot forming Changing the chemical composition Increasing its hardness and strength Softening the hard material What are the Heat Treatments Applied to Steels? Annealing: The heating and cooling process applied with certain properties to relieve internal tensions of steels and alloys, to eliminate structural defects that occur during hot and cold processing, and to easily process the hard structure is called annealing. By annealing, mechanical properties are improved and flexibility is increased. A homogeneous structure is obtained. Annealing involves heating in the austenite phase and then slow cooling. Surface Hardening is a heat treatment applied to obtain a hard and wear-resistant structure on the surface and a soft structure on the inside. It is done to obtain impact-resistant parts. It is a heat treatment generally applied to steels with a low carbon content. Austenitizing Austenitizing is applied to the steel in order to provide the microstructure desired to be obtained in the subsequent cooling process. Austenitizing process is one of the important heat treatments affecting mechanical properties. The hardness value reaches its highest point after a homogeneous austenitizing and quenching process. Tempering (Tempering) Tempering (tempering) is a heat treatment applied to remove the hardness of quenched steels and alloys and to provide toughness. In this process, the alloy is stabilized by keeping it at high temperature. Sudden cooling is applied to the alloy that is kept at high temperature for a sufficient period of time. Stress Relief The heat treatment applied to relieve the internal stresses that occur during the heat treatment without changing the hardness of the material is called stress relief. Stress relief reduces deformations that occur in the material during heat treatment. For this reason, stresses in steels are reduced by applying stress relief annealing. http://www.aht.com.tr/