A lot of high temperature equipment is used in the steel industry, with cordierite-mullite material mainly being used in high temperature blast furnaces, heating furnaces in the rolling mills, soaking pits and annealing furnaces, as well as other high temperature equipment such as coking furnaces.

A blast furnace converts air from room temperature to high temperature and normally is run on blast furnace gas or mixed gas, heating air to a temperature between 900 – 1600oC. The brickwork around the burners and checker bricks will often be exposed to fluctuating temperatures. This means that thermal-shock resistance is especially important for materials used in these areas.

Heating furnaces are used to heat steel billet or small steel ingots in the rolling mill or forge. The temperature is usually below 1600oC, often with continuous or cyclical heating systems for pre-heating, warming and soaking of which the temperatures for each area are 800-900oC, 1150-1200oC, 1200-1300oC respectively. The furnace linings can suffer thermal-shock, peeling and deformation due to the intermittent nature of the operation.

Soaking pits are used in the rolling mills to heat the steel ingots to rolling temperature, and allow the mill to roll them to different sizes. Continuous casters do not need to use soaking equipment. Due to the lid of the soaking pit often being opened, the body and lid of the pit need to be able to withstand sudden changes of temperature.

Annealing furnaces and other heat treatment furnaces are used to perfect and improve the steel’s properties. The common treatments are annealing, normalization, tempering, carburisation and nitriding. The temperature for such processes is usually between 500 – 1000oC, which is lower than that for heating furnaces and the soaking pit. The inner lining of the furnace will suffer chemical attack and is often opened which causes the temperature to vary, which in turn can damage the furnace lining.

Coking furnaces are an essential piece of equipment for coking plants. The aim is to heat coal in the absence of air to 500-1000oC, then use destructive distillation to obtain coke and other by-products. The furnace is comprised of a combustion chamber, coking chamber, regenerator, roof, door, chute and a chimney. The two ends of the coking chamber and doors can face sudden drops in temperature from 1000oC down to 500oC, and so materials with excellent thermal shock resistance are required to increase the furnace service life.

In the above applications, any areas with a temperature below 1250oC, which do not come in to direct contact with the molten iron or steel and where the temperature is often changing are all perfect conditions for cordierite-mullite material. We have especially product for the GEX and GEY cordierite-mullite recipes for use in the iron and steel industries, as the material cost is relatively low and it has excellent thermal shock resistance. A specially-developed cordierite mortar can be supplied with the bricks.