Pouring process is the key step of girth gear manufacturing. Improper pouring process will affect girth gear quality badly. So it is required to perform pouring in accordance with operation demands strictly.

Firstly, do well preparations:

1. Clean the pouring site to ensure the safety and smooth completion of the pouring process;
2. Check the quality, drying and preheating of the ladle, as well as the flexibility and reliability of the transport and tilting mechanism;
3. Take knowlege of the kinds of casting alloy, estimate the quantity of casting mould and the weight of needed metal liquid to prevent the shortage of molten metal and the insufficient number of casting mould.

In order to obtain qualified gear, strictly control the pouring temperature, pouring speed, and strictly obey casting operation procedures are important.

1. For pouring temperature. Pouring temperature has great influence on the quality of steel castings. Reasonable pouring temperature range should be determined according to alloy type, casting structure and casting characteristics. Choose the reasonable pouring temperature (generally 1540℃～1580℃ (the molten steel temperature in ladle)) according to the type of carbon steel.

2. For pouring speed. Under the condition of smooth discharge of gas in the mould cavity, higher pouring speed can be adopted for the casting part which requires simultaneous solidification, and the lower casting speed can be used as far as possible for the casting part which requires sequential solidification.

3. For the pouring operation procedures.
It is genealy required that:
a. When pouring large and medium sized girth gear, the molten steel in ladle should rest 1min ~ 2min before pouring;
b. After pouring and completing solidification, remove the pressing iron and box card in time, to reduce the casting shrinkage resistance, and avoid crack defects.

In recent years steel castings accounte for 12% of total output of castings, which has a great effect on the development of the casting industry. Great Wall Steel Casting arranges reasonably every step in the gear production, to improve gear quality and promote the development of steel casting industry.