What is define tempered?

Tempering is a process of heat treating steel or other materials to improve their mechanical properties, such as toughness and strength, by reducing their brittleness. The process involves heating the material to a specific temperature and then cooling it rapidly in water, oil, or air to form a hard structure. Then, the material is reheated to a lower temperature to relieve the internal stresses, which helps to increase its ductility and toughness without compromising its hardness. Tempering is commonly used in the manufacture of knives, swords, and other tools where strength and durability are essential. It is also used in the metalworking industry to increase the strength of materials such as steel and brass.