Four Pouring Methods of Oxidized Castable Refractory Bricks and Their Characteristics and Applications

Four Pouring Methods of Oxidized Castable Refractory Bricks and Their Characteristics and Applications

I. Introduction

Oxidized castable refractory bricks play a crucial role in high – temperature industrial applications. The pouring method significantly affects the quality and performance of these bricks. Here, we will discuss four common pouring methods: normal pouring, inclined pouring, quasi – non – shrinkage pouring, and non – shrinkage pouring.

II. Normal Pouring

A. Characteristics

1. In normal pouring, the molten refractory material is directly poured into the mold from a certain height. This method is relatively simple and easy to operate. The flow of the material follows the basic laws of fluid mechanics under gravity.
2. However, it may cause some problems such as the formation of air bubbles during the pouring process. These air bubbles can lead to porosity in the final brick, affecting its density and strength.
3. The pouring speed needs to be carefully controlled. If it is too fast, splashing may occur, and if it is too slow, the molten material may start to solidify prematurely in the funnel or during the pouring process, resulting in an incomplete filling of the mold.

B. Applications

1. Normal pouring is suitable for the production of refractory bricks with relatively simple shapes and lower requirements for density and porosity. For example, in some small – scale industrial furnaces where the temperature and pressure conditions are not extremely harsh.
2. It can also be used in the initial trial production stage when cost – effectiveness and simplicity of the process are more important than achieving the highest quality.

III. Inclined Pouring

A. Characteristics

1. In inclined pouring, the mold is placed at an angle. The molten refractory material is poured into the mold along the inclined surface. This method helps to reduce the impact of the pouring process on the mold and the molten material itself.
2. By pouring along the inclined plane, the air in the mold can be more easily displaced. It can effectively reduce the number of air bubbles trapped in the brick compared to normal pouring.
3. The inclined angle needs to be carefully adjusted according to the viscosity of the molten refractory material and the size and shape of the mold. An improper angle may cause uneven filling of the mold.

B. Applications

1. Inclined pouring is often used for the production of refractory bricks with more complex shapes. The angled pouring helps to ensure that the molten material can reach all parts of the mold smoothly, especially in areas with narrow channels or corners.
2. It is also suitable for refractory bricks used in medium – temperature industrial environments where a certain level of density and strength is required to withstand mechanical stress and thermal shock.

IV. Quasi – Non – shrinkage Pouring

A. Characteristics

1. Quasi – non – shrinkage pouring involves the use of special additives in the refractory material. These additives can control the shrinkage of the material during the solidification process.
2. During pouring, the material has better fluidity and can fill the mold more densely. After solidification, the volume change is minimized, reducing the formation of cracks caused by shrinkage.
3. The formulation of the refractory material for this pouring method is more complex. The selection and proportion of additives need to be carefully determined based on the base material and the desired performance of the brick.

B. Applications

1. This pouring method is widely used in the production of refractory bricks for high – temperature industrial furnaces with strict requirements for dimensional stability. For example, in some glass melting furnaces where the stability of the refractory structure is crucial to maintain the quality of the glass production process.
2. It is also suitable for applications where the refractory brick needs to have good resistance to thermal cycling. The reduced shrinkage helps to prevent the formation of cracks during repeated heating and cooling cycles.

V. Non – shrinkage Pouring

A. Characteristics

1. Non – shrinkage pouring is an advanced pouring technique. It utilizes high – performance refractory materials and precise control of the pouring process. The material has almost zero shrinkage during solidification.
2. The pouring process usually requires more advanced equipment and a more stable environment. Special mixing and pouring devices are often used to ensure the uniformity of the material and the accuracy of the pouring operation.
3. This method can produce refractory bricks with extremely high density and strength. The absence of shrinkage eliminates the potential for internal stress – related defects.

B. Applications

1. Non – shrinkage pouring is mainly used in the production of high – quality refractory bricks for critical industrial applications. For instance, in some semiconductor manufacturing furnaces where the temperature control and purity requirements are extremely high.
2. It is also essential for refractory bricks used in aerospace and nuclear industries where the reliability and performance of the refractory materials under extreme conditions are of utmost importance.

VI. Conclusion

Each of the four pouring methods for oxidized castable refractory bricks has its own characteristics and suitable application scenarios. The choice of the pouring method should be based on the specific requirements of the industrial environment, the shape and size of the refractory brick, and the performance requirements in terms of density, strength, and resistance to thermal and mechanical stresses. By understanding these methods, manufacturers can produce high – quality refractory bricks to meet the diverse needs of different industries.