Corundum Bricks on the Tapping Channel of the Heating Furnace
In the small and medium-sized steel rolling heating furnace with side discharge, the tapping trough is an important part of the heating furnace. The structure of the tapping trough is directly related to the energy consumption and service life of the heating furnace. Because corundum bricks such as chrome corundum bricks and zirconia corundum bricks have good high temperature wear resistance and slag resistance. As a result, it has gradually replaced water-cooled cast iron tapping channels and has been widely used in small and medium-sized steel rolling furnaces. Rongsheng refractories manufacturer provides you with high-quality refractories for steel rolling furnaces, such as corundum bricks on the tapping channel, etc.
Factors Affecting the Service Life of Corundum Bricks on the Tapping Channel
In actual production, improper construction and use often reduce the service life of corundum bricks on the tapping channel of the heating furnace. Therefore, it is of great significance to analyze the factors that affect the service life of corundum bricks and discuss measures to improve the service life of corundum bricks. To analyze the service life of corundum bricks on the tapping channel of the heating furnace, it is necessary to conduct a dialectical analysis from the characteristics of the corundum brick itself and the working conditions of the tapping channel of the heating furnace.
(1) Due to the high density of corundum bricks, thermal stability is poor. Therefore, it is easy to burst when the temperature changes sharply, especially near the tap hole. When the furnace pressure fluctuates frequently, the door of the furnace may burst into flames and sometimes suck cold air. As a result, the surface temperature of the corundum bricks fluctuates up and down, forming large internal stress. This causes the surface of the corundum brick to peel off and crack.
(2) The gap between the corundum bricks is not tightly sealed, and the oxide scale or its melt enters the gap and adheres to the upper oxide scale, forming a solid whole with the corundum brick. As a result, it is difficult to remove the oxide scale on the surface, and it must be removed with a big steel hammer. Doing so is easy to cause damage to the corundum brick, often cracked or knocked off.
(3) The masonry of the refractory bricks at the bottom of the corundum bricks must be smooth, and castables can be used to level them when they are uneven. It is not allowed to use loose thermal insulation materials, and it is not allowed to pay only part of it. In other words, the corundum bricks must be cushioned with hard refractory materials. Only in this way can it be ensured that the corundum bricks will not loosen when the billet slides on the corundum bricks. The loosening of corundum bricks will cause two undesirable consequences. One is to make the upper surface of the corundum bricks uneven, which affects the sliding of the billet and the elimination of oxide scale and reduces its service life. Second, the gaps filled with magnesia powder appear again due to the loosening of the corundum bricks, and the oxide scale will fall into it, which will cause difficulty in removing the oxide scale and reduce the service life of the tapping trough.
(4) Avoid “cutting” of corundum bricks by continuous casting billets. Most of the small and medium-sized steel billets have irregular shear sections. If the billet moves in the direction of the tapping channel, the surface of the corundum brick will be cut, which reduces the service life of the corundum brick. Therefore, when the billet enters the furnace, the placement of the billet should be adjusted to avoid the cutting of the corundum brick by the billet when it moves in the tapping trough, which can increase the service life of the tapping trough. Expansion joints or improper setting of expansion joints will make it have no room for expansion when heated, which will easily cause great internal stress, leading to premature damage to the corundum bricks and reduced service life.
How to extend the service life of corundum bricks on the tapping channel of the heating furnace?
(1) Reasonably control the furnace pressure so that the furnace pressure is always slightly positive. Especially when the steel rolling production is abnormal, attention should be paid to adjusting the flue gate at any time to keep the furnace pressure in a slightly positive state. Ensure that no cold air is sucked at the door of the tapping furnace so that the surface temperature of the corundum brick near the tapping port will not change frequently.
(2) The masonry gap between corundum bricks must be as small as possible. After the masonry is completed, the gaps must be filled and compacted with magnesia powder. Leave 30-50mm expansion joints at both ends of the tapping trough, which are filled with alumina silicate refractory fiber felt and covered with 30mm thick magnesia powder. In this way, the longitudinal expansion stress of the corundum bricks on the tapping channel can be eliminated, and the oxide scale can be prevented from falling into the expansion joints. The expansion joints on both sides of the tapping trough are the same as the two ends, but the expansion joint width is 10mm.
RS Refractories Bricks for Kinds of the Heating Furnaces
Rongsheng is an experienced corundum refractory brick manufacturer. Rongsheng’s refractory products have been sold to more than 60 countries and regions all over the world. For example, Thailand, UAE, Turkey, Kuwait, South Africa, Malaysia, Vietnam, Netherlands, Philippines, Singapore, Egypt, Russia, etc. Rongsheng’s refractory technology team aims to provide the most suitable refractory materials for the refractory lining of various thermal furnace equipment, including refractory bricks and refractory castables. If you need refractory equipment on your heating furnace equipment, please contact us. We will provide you with services according to your specific needs.
