Heat treatment method of transmission gear

Heat treatment method of transmission gear:

Surface hardening: Surface hardening:

Medium carbon steel and medium carbon alloy steel are generally used for surface quenching. After surface quenching treatment, the tooth surface hardness can reach HRC, good wear resistance, high tooth surface contact strength, 52~56. High-frequency quenching, flame quenching and other surface quenching methods.

2. Carburizing and quenching:

Carburizing and quenching treatment is carried out on low carbon steel and low carbon alloy steel. After carburizing and quenching, the hardness of the tooth surface can reach HRC56~62. The contact strength of the tooth surface is high, and the wear resistance is good, while the tooth center still maintains high toughness. Important gear transmissions subject to shock loads.

3. Tempering:

Quenching and tempering treatment is generally used to treat carbon steel and medium carbon alloy steel. After quenching and tempering treatment, the tooth surface hardness can reach HBS220~260.

4. Normalizing:

Normalizing can eliminate internal stress, refine grains, improve mechanical properties and cutting performance. In the gear transmission that does not require high mechanical strength, medium carbon steel can be used for normalizing.

After heat treatment, the tooth surface hardness HBS≤350 gear is called soft tooth surface gear, which is mostly used in medium and low speed machinery. When both large and small gears have soft tooth surfaces, considering that the root of the small gear is thinner, the bending strength is lower, and the number of loads is more, the hardness of the tooth surface of the small gear should be 20~50 higher than that of the large gear. HBS.

Gears with tooth surface hardness HBS>350 are called hard tooth surface gears, and the final heat treatment is carried out after the gear teeth are cut. Since the gears after heat treatment will be deformed, it is necessary to grind the gears with high precision requirements. When both large and small gears have hard tooth surfaces, the hardness of the small gear should be slightly higher, or it can be equal to that of the large gear.