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What is the heat treatment of heavy-duty gears?

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Update time : 2016-10-06 10:10:00
Heavy duty gear refers to gears with large transmission power, large bearing capacity, low speed, and large impact load. It mainly includes gears in general reducers and gears for main engines such as mining equipment, metallurgical equipment, building materials equipment, lifting machinery, large trucks, rail transportation equipment, aerospace equipment, military equipment, and ships, etc.
The heat treatment process of heavy-duty gear mainly includes three processes: carburizing hardening and tempering, nitriding and induction hardening and tempering.


Carburizing, hardening and tempering
After the carburizing and hardening and tempering process, the gear has the characteristics of high hardness, high wear resistance, high load carrying capacity and high impact toughness. Therefore, the carburizing and hardening and tempering process has become the leading heat treatment process when processing heavy-duty gears. At present, the heavy-duty gear carburizing process is mainly gas carburizing, and the development direction is vacuum carburizing.
The temperature required for the nitriding process is low, so part deformation is small. After nitriding, a high-hardness compound layer and a diffusion layer are directly formed on the gear surface, and the process is simple. Due to the limitation of the depth of the nitriding layer, the nitriding process is mainly used for heavy-duty gears with a modulus of less than 12mm.
Induction hardening
The modulus of induction hardened heavy-duty gears is not limited, so the induction hardening process has a wide range of applications. The induction heating speed is fast. At the same time, only the surface of the gear is heated, so after hardening, the gear has less oxidation and decarburization and the gear has less deformation. The quality of induction hardening is good, the surface hardness is high, and at the same time, high residual compressive stress can be formed at the gear root. Induction hardening has a deep enough hardened layer, which can achieve a uniform distribution of the hardened layer along the gear profile, and achieve simultaneous hardening of the gear root and the gear surface, and the hardening cost is low. The heavy-duty gear induction hardening process mainly uses medium frequency induction heating equipment to achieve gear hardening.