The hardened layer of gear is too shallow

The surface hardness of carburized gear is too shallow, which not only reduces the anti peeling performance of surface hardened layer, but also reduces the service life.

1. Cause analysis

(1) In the carburizing process, the carburizing time is too short, the carburizing temperature is low, the carburizing layer is too shallow, the temperature distribution in the effective heating zone in the furnace is uneven, the carbon potential in the strong carburizing stage and diffusion stage in the carburizing process is not controlled properly, the oil stain on the gear before charging is not removed, the charging amount is too much, and the remaining pores are too small, resulting in the shallow hardening layer of the carburized gear.

(2) The selected gear steel has poor material and hardenability, and the cooling performance of quenching medium is insufficient, resulting in shallow hardening layer after normal carburizing and quenching.

2. Preventive measures

(1) Select steel with appropriate hardenability as carburized gear material, strictly control the quality of gear steel, and check the quality standard of steel before entering the factory.

(2) Strictly control the surface quality of gear before carburizing, furnace charge, furnace temperature, furnace carbon potential atmosphere, strong carburizing and diffusion time, quenching temperature after carburizing, cooling medium, etc.

(3) The gears with insufficient carburization shall be carburized.

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