Vacuum heat treatment process of automobile gearbox gears

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Gearbox gears are located in the transmission part of the car and are used to transmit torque and power and adjust speed. Due to the transmitted torque, the tooth root

To withstand large bending stress and alternating stress; due to the wide range of gear speed changes in the gearbox, the gear surface is subjected to large

Contact stress, and withstand strong friction at high speeds; due to constant shifting while working, gear teeth are often subject to shifting

shocks and collisions. This requires high hardness and high wear resistance on the gear surface; high contact fatigue strength on the tooth surface;

The part has high strength and high toughness.

The technical requirements for vacuum heat treatment of the shown 20CrMnTi automotive gearbox gears are as follows:

1.The carbon content on the surface of the carburized layer is 0.80~1.05%;

2.The depth of carburized layer is 0.80~1.3mm; .

3.After quenching and tempering, the hardness of the tooth surface is 58~62HRC, and the hardness of the core is 33~48HRC.

In mechanical equipment, there are many parts (such as gears, crankshafts, piston pins, etc.) that are subject to shock loads and surface friction conditions

The surface of such parts needs to have high hardness and high wear resistance, while the core needs sufficient plasticity and toughness. to satisfy

The performance requirements of such parts require surface vacuum heat treatment.

Surface vacuum hardening of steel

Surface vacuum quenching is to austenitize the surface layer of the steel by rapid heating in a vacuum environment, and then rapidly cool, so that the surface layer forms a certain depth of hardened structure—martensite, while the core still maintains the original plasticity and toughness. Better microstructure vacuum heat treatment process. In the surface vacuum quenching method of steel, vacuum induction heating quenching is the most widely used.

Vacuum Induction Heating Surface Hardening

When surface quenching by vacuum induction heating, the workpiece is placed in an inductor made of copper tube, and alternating current of a certain frequency is passed into the inductor to generate an alternating magnetic field, so an induced current with the same frequency and opposite direction will be generated inside the workpiece. (vortex). Due to the skin effect of the eddy current, the distribution of the eddy current on the workpiece section is uneven, the surface current density is large, and the core current density is small. The higher the frequency of the current in the inductor, the more concentrated the eddy currents are on the workpiece surface. Due to the heat generated by the eddy current on the surface of the workpiece, the surface of the workpiece is rapidly heated to the quenching temperature (the core temperature is still close to room temperature), and then rapidly cooled by water spray (alloy steel immersed in oil for cooling), thus achieving the purpose of surface vacuum quenching.

Equipment selection: The RVGQ vacuum air quenching furnace provided by SIMUWU is an excellent product for handling this kind of process, with good temperature uniformity and high temperature control accuracy. SIMUWU provides a professional team of engineers who can solve various problems encountered in the production process and are committed to giving customers the most convenient and efficient experience.