The large girth gear is the main transmission component of the rotary kiln, ball mill and other equipment. As the rotary kiln and the ball mill are large-scale equipment, the girth gear is easy to wear during operation, and is also one of the accessories that often need to be replaced. Due to the poor lubrication conditions in operation, the harsh working environment, and the mixture of dust, sand, and other impurities in the lubricating oil or grease, the wear of tooth surfaces is exacerbated.

Some girthgears have a service life of only about a year and a half. The life of the pinion gear is even shorter. Sometimes it needs to be replaced within three months, seriously affecting normal production. Therefore, in order to increase the service life of large-diameter, difficult-to-cast, and long-geared ring gears, it is necessary to increase the hardness of the tooth surfaces and increase the wear resistance in addition to the reasonable selection of materials.

The large modulus design life of the rotary kiln gear ring is generally 10 to 15 years, but most of the gear ring life is only 8 to 10 years. The pinions wear faster and their life is typically 3 to 5 years, especially for dry and semi-dry cement kilns.chaeng adopts a gear surface quenching method, which significantly increases the hardness of the tooth surface and nearly doubles the service life.

Surface quenching should pay attention to:

1. It is not suitable to remove the ring gear from the quenching, otherwise, after the re-installation, the gears are deformed due to quenching so that the contact is not good;

2. Keep oxygen, acetylene and water pressure unchanged during operation;

3. The speed of movement should be appropriate. Too slow moving speed will burn the tooth surface and quench it too hard.

4. The water pressure of the water spray should not be too high, otherwise the flame will be extinguished;

5. During operation, the beginning of each tooth should be heated for a period of time, and the end of the tooth should be moved more quickly; otherwise, the end of the tooth can be easily melted;