Various types of heat treatment processes include:
1. Carburization treatment process
This process involves adding carbon atoms to the surface and subsurface of the steel to improve its surface hardness. This is to enhance the surface of metal components and improve their microstructure and mechanical properties by allowing carbon to diffuse into them.
The carbon content in the atmosphere, the type of material used, the temperature used, and the length of metal exposed to that temperature determine the depth at which carbon can diffuse. The time when hardening occurs after the part is quenched. In addition to increasing surface hardness, carburization can also improve fatigue strength and wear resistance.
It is most suitable for low steel with a carbon content between 0.05% and 0.3%, and can be used on parts with different complexities. For metals that require improvement in wear resistance, durability, and fatigue strength in expected applications ranging from 1562 ° F to 1832 ° F (850 ° C to 1000 ° C), carburization treatment is the preferred treatment method.
2. Treatment process nitriding
Similar to carburization, nitriding is a thermochemical surface hardening process used to improve the hardness, fatigue life, and wear resistance of metal parts. By nitriding, nitrogen diffuses to the metal surface to achieve hardening effect. The nitriding process involves heat treatment of ferrous materials, followed by exposure to active nitrogen at a strictly controlled subcritical temperature.
During exposure to active nitrogen gas, the application temperature range is between 752 ° F to 1094 ° F (400 ° C to 590 ° C), below the final tempering temperature, to ensure that the mechanical properties of the metal are not affected. When nitriding alloy steel materials containing nitride forming elements, nitriding is the most effective. This allows for the easy formation of alloy nitride precipitates through nitrogen and metal.
The following are examples of steels compatible with nitriding processes: 4140, 4130, 4150, 8640, 4340, 15-5, 17-4, 4xx stainless steel, and nitrloy 135. In addition to its hardening effect, nitriding can endow metal components with wear resistance, bite resistance, and welding resistance. Metals that have undergone nitriding treatment can maintain hardness at temperatures up to 1000 degrees Fahrenheit. These characteristics make nitride metals very suitable for countless applications, including bearings, molds, gears, shafts, nozzles, feed screws, orifice plates, splines, valves, cylinder liners, and piston rings.
