Metal Heat Treating Overview
Heat treating is an essential process for the manufacturing of many metal components. Heat treating is the process of changing the physical and/or chemical properties of a material to achieve desired results. Heat treating can affect the hardness, strength, machinability, and ductility of metals, as well as their magnetic, electrical, and chemical properties.
Types of Heat Treating
There are two main types of heat treating: hardening and tempering. Hardening involves raising the temperature of the metal to a specific degree and then quickly cooling it (quenching) to form a hardened structure in the material. The quench rate determines how hard the material will be. Tempering involves reheating the material to a specific lower temperature to reduce the hardness and improve the ductility.
Other heat treating techniques include annealing, stress relieving, and heat-treating/aging. Annealing is used to relieve internal stresses and improve machine-ability. Stress relieving is used to remove metallurgical stresses that can cause distortion during machining. Aging is used to increase strength, hardness, and erosion-resistance.
Heat Treating Processes
Heat treating processes involve the use of furnaces, heating elements, and coolers. Furnaces are used for preheating, hardening, tempering, and other heat treating operations. Heat treating furnaces can be fuel-fired, electric, gas-operated, or flame-hardening models. The most common heating elements are ceramic, electric, and gas. Coolers are used to rapidly cool the metal after heat treating, and can be either air or water cooled.
Metal Heat Treating Safety
Heat treating can be a dangerous process and requires a safe working environment. Heat treating furnaces can reach temperatures of up to 2000°F (1093°C), so proper safety precautions should always be taken. Materials used in the heat treating process will contain hazardous materials and should not be inhaled or ingested. Safety equipment such as protective clothing, goggles, and respirators should be worn.
Conclusion
Metal heat treating is a critical process in the manufacturing of metal components. Heat treating can be used to change the physical and/or chemical properties of a material to achieve desired results. There are many types of heat treating processes, including hardening, tempering, annealing, stress relieving, and aging. Metal heat treating is a potentially hazardous process and should always be performed in a safe working environment.
