Introduction
Heat treatment is a process used in the manufacturing of metal products and components for the purpose of changing their physical and sometimes chemical properties. Heat treatment is used in a wide range of industries, including automotive, aviation, electrical and medical manufacturing as well as military and defense. In China, heat treatment has been significant since ancient times, with the development of tools and weapons made from alloyed metals. China has a wide variety of standards for heat treatment, covering a wide range of applications and materials.
Overview of Heat Treatment
Heat treatment is a process in which metal is heated and cooled in order to affect its physical and mechanical properties. It is usually used to change the hardness, strength, and ductility of the material. Heat treatment can also be used to improve surface attributes such as corrosion resistance and fatigue strength. Heat treatments are also used to increase the wear resistance of a material, alter its metallurgical structure, or improve its machinability.
Types of Heat Treatment
Heat treatment is divided into three main categories: annealing, hardening, and tempering. Annealing is the process of heating a metal until it is soft and malleable, and then slowly cooling it to relieve internal stresses. Hardening is the process of heating a metal beyond its recrystallization temperature and then rapidly cooling, which increases its hardness and strength. Tempering is the process of reheating a metal after hardening, and then cooling, which reduces its hardness and strength while improving its ductility and toughness.
Standards
In China, the standards governing heat treatment processes are established by the Ministry of Industry and Information Technology of the Peoples Republic of China (MIIT). These standards cover a wide range of materials, including cast iron and steel, as well as non-metallic materials such as copper and zinc. The standards include procedures for heat treatment, definitions of relevant terms, as well as test methods for determining the properties of the material.
The Chinese standards for heat treatment include the GB/
