What should we pay attention to in pouring process?

Pouring process refers to the method and technology of pouring molten steel into steel ingots.

Pouring process is a crucial link in the whole production process of steel castings.The pouring process is not simply pouring the metal liquid into the cavity, because the molten steel in the process of melting, casting, and solidification will be connected with the surrounding medium (such as air, various refractory materials, etc.). A series of physical and chemical reactions will occur due to the impact of high temperature and fluid. Impurities, they will remain in the various parts of the casting.

Therefore, in steel casting production, we should strictly follow the requirements to carry out various operations in the casting process.

First of all, adequate preparations should be made before pouring to ensure smooth operation of the casting. 

Preparatory work before pouring includes:

a. Clean up the casting site；

b. Check the situation of the ladle and drying preheating, as well as the flexibility and reliability of the transport and tilting mechanism.

c. To understand the types of cast alloys, to estimate the quantity of the products to be poured and the weight of the liquid steel needed, to prevent the shortage of molten steel and the insufficient cast type in the casting.

In order to obtain qualified steel castings, it is very important to control the pouring temperature, pouring speed and strictly abide by the casting operation rules.

a. As far as pouring temperature is concerned, the pouring temperature has a great influence on the quality of the castings. The reasonable pouring temperature range should be determined according to the type of alloy, the structure of the casting and the characteristics of the mold. The reasonable pouring temperature is selected according to the type of carbon steel. The general pouring temperature is between 1540 ~1580℃.

b. In terms of pouring speed, under the condition of smooth gas discharge in the guaranteed cavity,for castings requiring simultaneous solidification, a higher casting speed may be adopted, and for castings requiring sequential solidification, a lower casting speed may be adopted as far as possible.

c. It is necessary to specify the pouring time to meet the pouring speed, that is to say, starting from the design of the cross section area of the gate.

d. The casting of organic binder sand mold is faster than inorganic binder.

e. Generally speaking, the following requirements should be observed for casting operation requirements:

1. Pouring large and medium steel castings, steel need to be placed 1min to 2min before pouring.

2. After casting solidification, iron and box cards should be removed in time to reduce shrinkage resistance and avoid casting.

In order to obtain qualified castings and prevent impurities from occurring, it is necessary to adopt corresponding pouring process according to the characteristics of the castings and metals. Therefore, the design of gating system plays a vital role in casting quality, so do not despise it.