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Refractories Used in Industrial Furnaces For Steel Rolling

1. Refractory Materials For Heating Furnace

The heating furnace is a thermal equipment used for heating billets or small steel ingots in a rolling mill or a forging steel plant. It is mainly composed of furnace roof, furnace wall and furnace bottom, as well as air and gas preheating devices, water-cooled pipe slide system, and flue And chimneys, etc.

The operating temperature of the heating furnace is generally below 1400 degrees. For continuous or annular heating furnaces, the furnace temperature of each part can be divided into low, medium, and high temperature zones, which are respectively called preheating zone, heating zone and soaking zone, and their temperatures are SOO-QOOt and 1150℃-1400℃ and 1200℃~1300℃. The damage of the furnace lining is mainly caused by temperature fluctuations caused by intermittent operation and furnace shutdown and opening, which lead to deformation of the furnace lining and thermal spalling; the damage of the furnace bottom and the root of the furnace wall is mainly caused by the chemical reaction between the molten oxide scale and the bricks. of. Therefore, appropriate refractory materials should be selected according to the conditions of different parts. The heating zone of the stove and the stove top of the soaking zone are made of high-aluminum hanging bricks, and the upper surface is covered with a layer of insulation board. The furnace wall is built with high-alumina bricks, clay bricks, light-weight clay bricks and thermal insulation boards in sequence. The furnace bottom of the heating zone is built with magnesia chrome bricks or magnesia bricks, clay bricks, light clay bricks and thermal insulation boards. Clay bricks are used for the inner working lining of the preheating zone. However, with the development of castables in recent years, the proportion of refractory castables used in heating furnaces is increasing, such as high alumina cement.

2. Refractory Materials For Soaking Furnace

The soaking furnace is composed of furnace cover, furnace wall, furnace bottom and heat exchange device. Its function is to evenly heat the steel ingots to the rolling temperature for rolling into large, medium and small billets, and then rolling them into various steels. If it is a continuous casting billet produced by a continuous steel casting machine, it can be directly rolled into various steel materials without heating through a soaking furnace.

In the past, the lining of the soaking furnace was mainly built with clay bricks, high-alumina bricks and silica bricks. The working layer at the bottom of the furnace bottom and the furnace wall was corroded by slag, and magnesia bricks or magnesia chrome bricks were generally used. Currently, monolithic refractories or prefabricated blocks are mainly used in soaking furnaces. Mainly use high-alumina castables containing stainless steel fibers. In short, integral casting furnace walls, light-weight thermal insulation castables for thermal insulation linings and refractory fiber products are its development trends.

3. Refractory Materials For Heat Treatment Furnace

Heat treatment furnace mainly refers to thermal equipment that heats metal to change its performance and structure. Various heat treatment processes include annealing, normalizing, quenching and tempering, carburizing and nitriding. The use temperature of heat treatment furnace is generally lower than that of heating furnace and soaking furnace. The general temperature is 500℃~?1000℃, and there is no chemical erosion. Therefore, the furnace lining generally uses clay bricks, light clay bricks and light high alumina bricks. Sometimes high alumina bricks, cordierite bricks, silicon carbide bricks and corundum bricks are used in the parts. At present, light refractory materials and refractory fibers are widely used as furnace linings.

Shanghai Geheng Vacuum Technology Co., Ltd. is a vacuum heat treatment furnace manufacturer with many years of experience in design, manufacturing and production. It mainly produces true air quenching furnaces, double chamber vacuum oil quenching furnaces, vacuum annealing furnaces, vacuum tempering furnaces, and other vacuum furnaces.