Chrome corundum brick is a corundum refractory brick containing Cr2O3. At high temperatures, Cr2O3 and Al2O3 form a continuous solid solution, thus the high-temperature performance of chromium corundum bricks is superior to that of pure corundum bricks. Chromium corundum bricks used in petrochemical industry gasifiers should be low silicon, low iron, low alkali, high purity, and also have high density and strength. Most commonly used chromium corundum bricks have a Cr2O3 content ranging from 9% to 15%.
Chromium corundum bricks are also known as high wear-resistant chromium corundum tapping groove bricks. It is a high-end product that our company has promoted to the market in recent years. It is synthesized using pure alumina Al2O3 and chromium oxide Cr2O3 as the main raw materials. Compared with pure corundum bricks, it has better performance, such as fire resistance, load softening deformation temperature, flexural strength, high-temperature creep, high-temperature volume stability, and slag corrosion resistance. Mainly used for sliding rails, tapping platforms, grooves, and other easily worn parts of industrial furnaces in steel rolling heating furnaces. Chromium corundum brick is a high-grade refractory material with a service life of 10-18 months after being used by multiple steel rolling mills.
Practice has shown that the application of high wear-resistant chromium corundum tapping groove bricks in heating large cross-section steel billets, high friction per unit area, and high production of steel rolling heating furnace tapping grooves can not only significantly prolong the service life of the tapping groove, reduce furnace shutdown time, increase production, reduce refractory material consumption and maintenance costs, but also improve the overall service life of the furnace due to the reduction of quenching and heating times caused by furnace shutdown maintenance, Significant economic benefits can be achieved.
Physical and chemical indicators:
Project | Indicators |
Chemical composition (%) | Cr2O3> | 18 |
Al2O3> | 75 |
Volume density after burning, (g/cm3) | 3.3 |
Linear change after burning (%) 1500 ℃, 3h | +0.2~-0.2 |
Compressive strength |
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Product features:
1. High density, uniform and consistent surface and inner structure, low porosity, high strength, and good high-temperature wear resistance.
2. Good resistance to sudden cold and heat. In the area near the tapping furnace door and the end side opening furnace door, although the temperature changes frequently due to frequent opening of the furnace door, there has been no cracking phenomenon in the tapping groove bricks so far.
3. Good slag resistance. The oxide scale does not bond with the tapping groove bricks, and some slag is carried out with the steel billet during tapping, which can reduce the number of slag cleaning times in the production process and reduce the labor intensity during slag cleaning.
4. Some products can still be turned upside down during furnace repair, which can reduce maintenance costs.
5. This type of steel outlet brick does not have a casting riser, and its external dimensions are accurate. After masonry, the surface of the steel outlet is flat, and can be processed according to needs during construction.
6. The price of this type of Italychrome corundum brick for steel tapping is not only significantly lower than that of steel tapping bricks made of high alloy heat resistant and wear-resistant materials. And it is also lower than the fused zirconia corundum brick, which is undoubtedly a favorable factor for reducing production costs.
manufacturing process
Using high-purity industrial aluminum oxide powder and high-purity chromium oxide as raw materials, accurately weigh and mix according to the design ratio, fully grind and mix, add a certain amount of binder, mix evenly, and press into a blank. After the raw material is dried, it is melted or calcined to produce chromium corundum. Chromium corundum is crushed and sieved, and a portion is ground into fine powder. Mix the granular material and fine powder according to the optimal gradation, add a certain amount of binder, mix thoroughly and evenly, and then use a friction brick press or hydraulic brick press to form. After the body is dried, it is fired at 1800 ℃.
In addition, some will have high purity α- After mixing Al2O3 powder with Cr2O3 in a certain proportion, grinding and fully mixing, it can be directly used as a brick making powder.
purpose
Mainly used as the lower lining of the petrochemical industry residual oil gasifier and the tapping groove of the heating furnace.