4 solutions for serious damage to refractory materials used in ladle lining

 Ladle turnover process: converter/electric furnace tapping once and twice refining process, continuous casting and pouring steel, ladle preparation work, and waiting for tapping. The normal turnaround time depends on the steel type and the continuous casting machine, and it takes 100 to 140 minutes. The tapping temperature of the ladle is 1680-1700℃, and the holding time is 100~120min. If the ultra-low carbon steel process such as silicon steel, bridge steel, automobile plate steel, etc must be vacuum treated, argon blowing and stirring at the bottom of the ladle and LF furnace are used at the same time. Arc heating, reducing atmosphere in the furnace, white slag refining, gas stirring, etc., strengthen the comprehensive refining effects of thermodynamics and kinetic conditions, desulfurization, alloying, and heating, so the slag alkalinity range is large, and the temperature of molten steel and slag is higher. The residence time of molten steel in the ladle is prolonged, the thermal shock is strong, the stirring force is large, and the damage to the inner lining of the ladle is aggravated.

The reasons for the damage of the ladle refractories are as follows:

First, the ladle is used to transport high-temperature molten steel. During transportation, high-temperature molten steel and molten slag at around 1680°C will erosively corrode it, especially at the slag line. The scouring erosion is more serious, which is an important factor in determining the service life of a tank.

Second, the refining treatment outside the furnace such as LF seriously damages the unburned bricks.

Third, the inner lining is subjected to severe temperature changes when the converter is tapped and molten steel flows out, which causes cracks and peeling of the inner lining material.

Fourth, when the ladle is filled with molten steel during the tapping of the converter, the high-temperature molten steel has strong mechanical erosion on the bottom of the ladle, which makes the lining material of this part prone to damage due to thermal shock. According to the above analysis, the ladle lining refractories should have the following characteristics: compact and uniform structure; high temperature micro-expansion, good volume stability; High strength, small ratio of medium temperature strength to high temperature strength.

In addition to the above-mentioned two chemical and physical reasons, there is another reason that cannot be ignored is man-made:

(1)Improper selection and collocation of refractory materials;

(2)Improper use of refractory materials, such as unreasonable masonry and baking methods;

(3)Too long ladle turnover period causes cold ladle;

(4)Improper unpacking will damage the permanent layer of the ladle;

(5)Failure to take repair measures in time. The method to reduce the structural spalling of refractory materials is to reduce the depth of slag penetration.

It is recommended to start from the following aspects: 

(1)Improve the slag penetration resistance of refractories;

(2)Reduce the porosity of refractory materials and reduce the erosion channel of slag;

(3)The slag reacts with the refractory material to form a high melting point compound retaining wall to prevent the penetration of the slag;

(4)Increase the viscosity of the slag. The greater the viscosity of the slag, the worse the corrosiveness to refractory materials;

(5)Understand the properties of the refractory materials used, and reasonably formulate the use conditions of the ladle;

(6)Speed up the use cycle of ladle as much as possible, and achieve "red envelope" work;

(7) The damaged parts of the lining refractories should be repaired or replaced in time.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality ladle magnesia carbon bricks are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us. Our team would make best to be your reliable partner!

Ladle Magnesia Carbon Brick:?Magnesia carbon brick is made of fused magnesia and high carbon graphite, with antioxidant was added, and the phenolic resin was used as the binder for high pressure molding. MgO-C refractory bricks are widely used in steel industry.

Ladle Purging Plug:Ladle purging plug has been in the leading position in domestic and abroad over years. We have developed the series of corundum, chromium corundum, low silicon chromium corundum and corundum spinel one after another.

Ladle Slide Gate Plate:Slide gate plate is preferred products for big/medium ladle and continuous casting tundish. Alumina-carbon slide gate plates can meet the requirement of different steel grades.

Ladle Castable:Ladle castable has good workability, high strength, good volume stability, good abrasion resistance and thermal shock resistance, etc.

Article Source:4 solutions for serious damage to refractory materials used in ladle lining
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