The metallurgical industry relies on the refractory industry for building materials. The ceramic industry also takes the metallurgical industry as the main refractory material market. In this country, they consume more than half of the total output. According to a study conducted at 1W$, open hearth furnaces absorb more than one-third of refractory bricks, blast furnaces and heating furnaces each account for about 7%, cupolas and smelting furnaces each account for 3% to 4%, and malleable iron plants account for about 2%.
Bottom: The open hearth bottom usually consists of a metal plate lined with refractory bricks, followed by alkaline or neutral bricks, and finally a sintered layer of calcined magnesite mixed with 10% to 2.5% open hearth slag. Until about 10 years ago, magnesite bricks were almost exclusively used at the bottom of the kiln. Nowadays, due to cost reasons, the magnesite bricks at the bottom have been replaced by chrome bricks. In some factories, broken chrome ore is covered on chrome bricks, and a thinner layer of magnesite and slag is used in the furnace. But the general practice is to use magnesite bricks around the tap hole, and some companies use full magnesite bottoms.
Roofs: The temperature in the ceiling open hearth is 0° to 3000°F. The refractory materials in ceilings and walls must not only be able to withstand this high temperature but also must be able to withstand sudden changes in temperature with solid particles. Almost all kilns have spring arches, and refractory materials must withstand considerable pressure without softening, crushing or warping. The iron oxide coming out of the bathroom gradually eroded the silicon tiles on the ceiling, eventually causing leakage. Various types of roof tiles have been tested, but none is more satisfactory than silica.
Front and rear walls: If the same refractory material is used, the life of the front and rear walls is usually shorter than that of the roof. The deterioration is caused by the absorption of iron oxide from the airflow, the cutting action of the flame, and the p
eeling. The latter is especially bad on the front wall, especially the door frame. The slag splashing from the bathtub and the iron silicate dripping from the ceiling also have some chemical attack. Quite a few cliangcs have been done in wall design. Most ovens now have a slanted back wall, and many ovens also have a slanted front wall. The lifespan is shortened, and patches and plasters are easier to protect them.
Control room: The control room is designed to absorb 210 Szclliaan heat from the exhaust gas and return it to the air or gas for combustion as much as possible. The requirements are high heat capacity, high thermal conductivity, resistance to dust and slag and resistance to peeling caused by temperature changes. The maximum
temperature of the upper tester varies greatly among different ovens, but it is generally 2! 300" at 2600°F. In the so-called cold grid, dust usually settles under loose sintering conditions, and occasionally in a very hot room, the dust will react with the grid bricks. The air grid is usually clogged and must be cleaned frequently. Because the blockage slows down the production speed, and then affects the quality of some steels.
Steel Spoons: Coated spoons for steel fillers are one of the most difficult fire resistance challenges in the fireplace industry. Substances can be removed with an acid coating. On the other hand, nuclear cookware is unsatisfactory and only uses flame tools. The stone is slightly soft and not resistant to heat. The lift is small. Normal service life is 8-10°C, but it can record 30-40°C. Using a clay solution can extend the life of the primer, but it will affect the cleanliness of the steel. High carbon steels tend to overheat more easily than low carbon steels.
Nozzles require great care and must be carefully modeled and drawn. The opening should be sufficiently heat-resistant, but flexible enough to hold the lid in place. It must resist cutting of the molten steel stream and not pollute the steel. Magnesium seals are now available for specialty steel castings that are more expensive to clean. Seals are usually made of clay and graphite. It is very heat resistant and has a nice mouth that is somewhat plastic at high temperatures. Long arm bricks made of fireclay. The construction and feel of the sleeves and gaskets must be such that there is no risk of the internal steel or sealing rods being immersed in water.