Low pressure vacuum carburizing and high pressure air quenching technology of gear

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Low pressure vacuum carburizing and high pressure air quenching technology has the advantages of no internal oxidation, good surface quality, small deformation, good process stability and repeatability, excellent comprehensive performance of heat treatment parts, long service life, pollution-free and pollution-free, low power consumption, low production cost, high degree of automation, etc., which has been widely used in automobile engines, automobile transmissions, aeroengines and motorcycles Heat treatment of car gear and other parts.

1. Low pressure vacuum carburizing (LPC) technology

Conventional gas carburizing is easy to produce internal oxidation (Igo), and non martensitic structure appears in the surface layer of carburizing layer, thus reducing the fatigue performance of gears. Low pressure vacuum (1333 ~ 1.33 × 10-1pa) carburizing is used for gear and structural steel parts, which can improve the quality of carburizing layer and have no internal oxidation on the surface. The vacuum carburizing process controlled by computer simulation is adopted, with shorter processing time and less carburizing gas consumption, to ensure good carburizing effect: the depth deviation of carburizing layer is ≤± 0.05mm, and the uniformity of surface carbon content is ≤± 0.05%. Acetylene instead of propane carburizing has become the development trend of vacuum carburizing. The conventional carburizing heat treatment has a long cycle. This technology can realize carburizing at high temperature (950 ~ 1050 ℃), so as to improve the carburizing speed. It is one of the important methods for energy saving in heat treatment.

2. High pressure gas quenching (hpgq) technology

After carburizing, gear parts are cooled in gas more evenly than in liquid, so the distortion of quenching is small. Many gases can be used as gas quenching gases, such as argon, helium, hydrogen, nitrogen and their mixtures. At present, 85% ~ 95% of the gas quenching chamber adopts nitrogen, and the quenching pressure is usually 2MPa. High pressure gas quenching can control the pressure and flow of the (inert) gas, change the cooling characteristics of the gas, and combine with the transformation phase diagram of the undercooled austenite of the steel to achieve the most ideal quenching cooling, so as to reduce the gear distortion and improve the core strength.

3. Low pressure vacuum carburizing and high pressure gas quenching technology

Low pressure vacuum carburizing can not only effectively avoid the non martensitic structure defects on the surface of conventional carburizing and quenching, but also significantly improve the surface quality of gears and other parts. Combined with high pressure gas quenching, it can significantly reduce the distortion of heat treatment. By increasing the carburizing temperature, the processing time can be reduced, thus reducing the energy consumption and gas consumption. Therefore, the combination of vacuum low-pressure carburizing and high-pressure gas quenching is an advanced carburizing and quenching technology, which can be called environmental friendly green heat treatment technology in a real sense.

Learn More: Vacuum Carburizing Furnace