How to choose right refractory materials used in furnaces

 This article will introduce the types and application fields of refractory materials. Through this article, you can have a comprehensive understanding of refractory materials and learn more about the advantages of refractory materials. On the other hand, understand the main use areas and manufacturing processes of refractory materials.

How to choose right refractory materials

Refractories should have high structural strength and can withstand long-term mechanical loads at operating temperature. Refractories should have good resistance to the components of the batch materials, molten glass and gaseous substances. Refractories should produce minimum contamination to the glass.

Types of Refractory Materials

1. Fired Refractory Products

2. Non-Fired Refractory Products

3. Special Refractory

4. Monolithic Refractory (Bulk Refractory Or Refractory Concrete)

5. Functional Refractory Materials

6. Clay Bricks

7. High Alumina Bricks

8. Silica Bricks  

9. Magnesium Bricks

10. Corundum Bricks

11. Ramming Material 

12. Plastic Refractory 

13. Casting Material

Refractory material characteristics:

Depending on the working conditions of various steel furnaces, the working conditions of refractory materials were found to be very difficult. Therefore, the refractory materials used must have the following characteristics:

High-temperature resistance and high fire resistance.

Wear resistance and wear resistance of heat-resistant steel and slag.

For the intermittent operation of the steelmaking furnace, the refractory material must have excellent thermal shock and fracture resistance.

It has high mechanical strength, can tilt the blows of the furnace, and withstand the load of the furnace without damage.

There are many operations and processes for secondary steelmaking, such as vacuum degassing and ladle refinancing. Refractory materials use a unique combination of various bricks to meet diverse requirements. The following can be observed:

The high temperature and long retention time of molten steel in the ladle.

Wide variation of slag composition Various types of vacuum treatment. Thermal changes.

The stirring of molten steel causes erosion of molten steel movement.

In all ladle refining processes such as ladle furnaces, ASE-SKF and VAD processes,ladle MgO-C bricks are used in areas where slag and steel are in contact. For general walls, high alumina bricks are widely used. The bottom zircon bricks are used to prevent molten steel from penetrating into the joints of the bricks. In some cases, MgO-C, Al2O3-C bricks and molds are used in the impact area. MgO-C bricks with added metal pairs have high thermal strength and excellent oxidation resistance.

Refractory materials include natural ores and various products made by certain purposes and requirements through certain processes, which have certain high-temperature mechanical properties and good volume stability. They are the necessary materials for various high-temperature equipment.

FAQ:

How do you select refractory materials?

Refractories should have stable volume at high temperature and the residual expansion and contraction should be small. Heat capacity, thermal expansion coefficient, thermal conductivity and other thermal properties should meet the requirements. Refractories should have neat appearance and accurate shape and size.

What are the basics of refractory materials?

Refractory material is a material that is resistant to decomposition of heat, pressure or chemical attack and retains strength and form temperatures. The basic refractory materials include alumina, silica, magnesia and lime.

How are refractory material made?

This process involves using an electric arc furnace to melt the refractory raw materials, then pouring the melted materials into sand-forming molds. Another type of refractory process is ceramic fiber production. In this process, calcined kaolin is melted in an electric arc furnace.

Through this article, you already had an in-depth understanding of the advantages and application fields of refractory materials.What’s more,you can also view company news to learn more about refractory  industry news. If you need refractory materials, please contact me.

Article Source: https://www.cxrefractories.com/en-refractory-news?article_id=1260
Company name: Henan Changxing Refractory Materials Co.,Ltd
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Why is the R.U.L of refractory materials a key indicator

 The actual temperature that the refractory product can withstand is slightly higher than the load softening temperature, mainly for two reasons. First, in actual use, the load on the refractory product is generally lower than the load during the measurement; The second is the masonry in metallurgy. The refractory fire bricks in the furnace are only heated on one side.

Since the temperature experienced in actual use is higher than the load softening temperature, higher requirements are imposed on the refractory product. The softening temperature of the refractory product depends mainly on its chemical mineral composition and microstructure. The crystalline phase forms a network backbone, and the load softening temperature of the material is high. If the structure is dispersed in the liquid phase in an island shape, the load softening temperature is determined by the content of the liquid phase and its viscosity. For example, the more the liquid phase or the smaller the viscosity, the lower the load softening temperature. The interaction of both the crystalline phase and the liquid phase also changes the amount and nature of the liquid phase. The degree of compactness of the product also has a certain influence on the softening temperature of the load. The commonly used magnesium brick phase composition, mainly periclase crystals, is bonded together by the combination, so the load softening temperature of the magnesium bricks depends on the nature of the combination. The combination of magnesia bricks is generally a low-melting silicate phase such as calcium forsterite and magnesium rosewood. Due to the melting point phase of the periclase crystal, the viscosity at low temperature is low, and the magnesia brick exhibits a low load softening temperature. This is where the magnesia bricks need to be tackled.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality refractory products 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!

Article Source:Why is the R.U.L of refractory materials a key indicator
Company name: Henan Changxing Refractory Materials Co.,Ltd
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Refractory materials for different furnaces

 

1) Refractory for BOF

At present, ladle magnesia carbon bricks are used for the furnace cap, tapping port, front and rear large faces, molten pool and furnace bottom of the converter; high-strength magnesia carbon bricks are used for the trunnion and slag line parts.

The MgO content in the magnesia carbon brick is generally 70% to 75%, the graphite content is 16% to 20%, the bulk density is 2.8g/cm3 to 2.9 g/cm3, and the compressive strength is 25 to 30 MPa.

High-strength magnesia carbon brick with the same composition as magnesia carbon brick, but the compressive strength is 30 ~ 42MPa.

2) Refractory for EAF

The furnace bottom, furnace slope and molten pool of the electric furnace are integrated with magnesia, or magnesia bricks combined with magnesia carbon brick and tar pitch; hot and slag line areas, using high-quality magnesia carbon bricks; Both sides of the furnace door and tapping El it is a magnesia brick and a chrome-magnesia brick; the electric furnace cover is a high-aluminum brick or a high-aluminum non-burned brick.

3) Refractory materials for ultra high power electric furnace

The permanent lining of the ultra-high power electric furnace is magnesia, the side column of the furnace door is magnesia chrome brick, the slag line is magnesia brick, the hot spot is magnesia carbon brick, the furnace wall is magnesia carbon brick, the eccentric bottom and the molten pool are magnesia brick, out the steel mouth is magnesia carbon brick, the electric furnace cover is high aluminum brick, and the tapping hole filler is high iron dolomite filler.

4) Refractory for open hearth furnace

It can be seen from the working conditions of various steelmaking furnaces that the working environment of the refractory material is very bad, therefore, no matter what refractory material is used, it must have the following properties:

(1) High temperature resistance and high refractoriness.

(2) Erosion and erosion of high temperature resistant steel and slag.

(3) The steelmaking furnace is intermittent operation, and the refractory material is required to have good thermal shock resistance and peeling resistance.

(4) It has high mechanical strength and can withstand the impact of the furnace body tilting and loading into the charge without damage.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality refractory products 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!

Article Source:Refractory materials for different furnaces
Company name: Henan Changxing Refractory Materials Co.,Ltd
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Problems existing in waste refractory materials and classified reuse

 At present, China's refractory materials, annual output of waste reached 7 million tons, the amount is very large. The existence of these waste materials not only occupies the land, but also causes serious pollution to the environment, which is not conducive to the realization of the current concept of energy conservation and environmental protection. In recent years, with the development of enterprises, most companies have begun to recycle waste resistant materials. In metallurgical auxiliary materials branch of pangang group, for example, by using waste material recycling, resistant to the abandoned refractory material made of various materials, such as magnesite brick masonry wall with the furnace, the taphole with skateboard, masonry in blast furnace cover with high alumina brick, etc., used in pangang's factory production, greatly reduce the production cost of enterprises.

I. The existing problems in the reuse of waste refractory materials in China
1. Lack of awareness
At present, some enterprises use simple workshop production and products are relatively simple. The development of the enterprise has had an impact. They only pay attention to the purchase of raw materials, but pay little attention to discarded durable materials. There are some misunderstandings.
2. Lack of relevant research and technology
In China's current development, due to the relatively late start of the utilization of abandoned refractory materials, although some enterprises such as panzhihua steel and baosteel have made some progress in the relevant utilization in recent years, there are still some deficiencies in the depth and breadth of studies, and the overall utilization rate is still low.
3. Lack of reasonable classification
In some enterprises, all kinds of waste refractory materials are stacked together. However, due to the different degree and nature of some output burns, this will affect the processing efficiency in the later stage, and also make the utilization rate of the waste refractory materials not meet the high requirements.

Ii. The recovery method of waste refractory materials
1.Direct use
In the abandoned refractory materials, it is called direct utilization method that is not processed but directly used after removal. For the permanent layer and some places that are not very important, even after the liquid metal container is used up, the damage caused is relatively small, and even some resistant materials do not have obvious changes. So these materials can be directly used to the place with low safety requirements or not the main location. This method can be implemented relatively few varieties of waste materials, but can achieve the purpose of making the best use of everything, as far as possible to reduce the problem of waste.?
2.Primary use
After simple selection and grinding, the waste refractory is made into different granules for use, which is called the primary use method. It can not only solve environmental protection problem, but reduce the occurrence of environmental pollution problem.
3.Intermediate use
Based on the primary use method, the abandoned refractory is further processed by physical and chemical processing, so that the level of the refractory is closer to that of the original material. For example, after the waste skateboard is processed and used as the raw material of the skateboard, the skateboard produced is the same as the new one.
4.Advanced usage
Based on the synthesis principle of the new material, after the grinding process, the following advanced use methods can be used:
(1)after some materials are added, new materials are synthesized by means of high-temperature physical and chemical principles;
(2)as a raw material, pure substances are extracted, such as metallic chromium produced by the purification and reaction of high-chromium brick, which may produce great value;
(3)process them into micro powder or nanometer powder.
The first two methods are more common in current use.

Iii. Classification and utilization of waste refractory materials
1.Waste magnesia carbon brick
After the waste magnesia carbon brick is recycled, it can be directly used and added into the mixture of magnesia carbon brick such as ladle slag line free surface, with the proportion of 30%-50%. All the properties of the waste magnesia carbon bricks recovered before and after utilization are better than the standard indexes. Therefore, it is feasible to recycle magnesia - carbon brick.
2.Waste aluminum magnesium carbon brick
In the production process of aluminum-magnesia-carbon brick with the same material, the waste aluminum-magnesia-carbon brick can be properly added, and the aluminum-magnesia-carbon brick can be broken into fine powder to produce the refractory mud with the same material, so that it can be used in the construction of aluminum-magnesia-carbon brick.
3.Waste magnesia brick and magnesia chrome brick
After the slag-gully castable and waste magnesite brick are crushed, the appropriate amount of addition of magnesite chrome brick raw material and magnesite brick raw material can also be appropriately added in the raw material of magnesite slag-retaining weir plate, and refractory mud can be produced after processing.?
4.Waste high-alumina brick
Waste high alumina bricks can be processed into fine powder to produce refractory mortar. For the granular part, can be used in plastic refractory with different temperature. For example, the castable used in the ladle cover and the plastic refractory used in various repairs.

Iv. Prospect of resource recovery of discarded refractory materials
At present, there are two main ways for the comprehensive utilization of the abandoned refractory materials: machine degraded use, repair use and the pure granule mixing type utilization. Through the research and analysis of the homogenization technology, separation technology and purification technology, part or all of the recycled materials are transformed to replace the genuine particles, so as to improve the comprehensive utilization rate and increase the added value of the products to the maximum extent. At the same time, it is necessary to further study the recycling of high-grade waste refractory materials, so as to make the application of waste refractory materials more extensive.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality refractory products 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!

Article Source:Problems existing in waste refractory materials and classified reuse
Company name: Henan Changxing Refractory Materials Co.,Ltd
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The cement kilns are made of green and energy-saving refractory materials

 "With green energy-saving refractory cement kiln" main technical indicators:?

 

1) Magnesium iron and aluminum spinel brick: volume is about 2.9 g/cm3 density, coefficient of thermal conductivity (25 ℃ to 350 ℃ +) 3.50 w/m.k;

2) Low thermal conductivity of magnesium aluminum spinel brick: volume density (work) 2.90 ~ 3.05 g/cm3, thermal insulation layer is not higher than 2.65 g/cm3, coefficient of thermal conductivity (700 ℃), 3.713 w/m.k, of which 2.508 w/m.k insulating layer;

3) Low thermal spalling brick: 30 volume density is not higher than 2.2 g/cm3, coefficient of thermal conductivity (700 ℃), 1.433 w/m.k;

4) Low thermal spalling brick: 50 volume density is not higher than 2.4 g/cm3, coefficient of thermal conductivity (700 ℃), 1.58 w/m.k;

5) Heat loss of kiln body: 82.31 ~ 84.38 kJ/ KGCL.This product for the low thermal conductivity series new materials, refractory materials used for cement kiln of all matching, low thermal conductivity, energy conservation and greatly reduce the cement kiln cylinder surface temperature and heat loss, the service life of the refractory materials used for cement kiln and repair cycle coordination and synchronization, improve the production efficiency.At present, the product has been used in many cement production lines.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality tundish dry vibration mix 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!

Article Source:Ladle magnesia refractory castable mixing notes
Company name: Henan Changxing Refractory Materials Co.,Ltd
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4 indicators that determine the high temperature performance of refractories

 Refractory materials are subject to physical, chemical, and mechanical effects at high temperatures (usually 1000~1800°C) during use, which are easy to melt and soften, or are corroded, corroded, or cracked and damaged, causing the operation to be interrupted, and Contaminated materials. Therefore, it is required that refractory materials must have properties that can adapt to various operating conditions.

(1) Refractoriness

Refractoriness refers to the temperature at which a material reaches a certain degree of softening under the action of high temperature, which characterizes the performance of the material against high temperature. Refractoriness is the basis for judging whether a material can be used as a refractory material. The International Organization for Standardization stipulates that inorganic non-metallic materials with a refractoriness above 1500°C are refractory materials. It is different from the melting point of the material, and it is a comprehensive performance of a mixture of multiphase solids composed of various minerals.

(2) High temperature load deformation temperature

Also known as the refractory softening point under load or the refractory deformation temperature under load, it means the resistance of the refractory to the combined action of high temperature and load under a constant load or the temperature range in which the refractory exhibits significant plastic deformation. The maximum use temperature can be inferred from the refractory material’s load softening temperature.

(3) High temperature volume stability of refractories

Refractory materials produce volume expansion under the action of high temperature for a long time, which is called residual expansion. The size of the residual expansion (deformation) of refractories reflects the quality of high-temperature volume stability. The smaller the residual deformation, the better the volume stability; on the contrary, the worse the volume stability, the easier it is to cause deformation or damage to the masonry.

(4) Thermal shock stability

The ability of refractory materials to resist sudden changes in temperature without being damaged is called thermal shock stability. This performance is also called thermal shock resistance or temperature sudden change resistance.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality refractory products 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!

Article Source:4 indicators that determine the high temperature performance of refractories
Company name: Henan Changxing Refractory Materials Co.,Ltd
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Classification of steel converters and refractory materials required

 

1. Oxygen top blowing converter

Oxygen top-blowing converter is the most widely used one in steelmaking converters. It is to charge the main raw materials, namely molten iron and return to work, into the furnace, add limestone, fluorite and other auxiliary materials, and then pass the oxygen gun through the furnace mouth. A steelmaking method in which pure oxygen is blown into molten iron for smelting. The oxygen top-blowing converter has the advantages of not using foreign fuels, low equipment and production costs, high production efficiency, and fast construction speed. Therefore, it has been rapidly popularized and has become the main equipment for contemporary steelmaking.

2. Electric (arc) furnace

The steel-making electric (arc) furnace stone is first charged with scrap steel or reduced iron, and the furnace charge is melted by the electric arc generated between the charge and the electrode, and the refining operation is carried out under the condition that the electric arc continues to heat. The molten steel with the required composition and temperature is a kind of thermal equipment that converts electrical energy into heat to smelt metal. Electric (arc) furnace steelmaking has the advantages of using scrap steel as the main raw material, high temperature, capable of controlling the atmosphere in the furnace, and particularly suitable for smelting alloy steel.

3. Mixing furnace

The mixer is a thermal equipment for storing molten iron in the steelmaking workshop.

4. Mixed rail car

The iron mixer is also called a torpedo car because it resembles a fish. It is a kind of thermal equipment for storing and transporting molten iron from the blast furnace to the transfer workshop.

5.?Iron furnace

The cupola (cupola) is one of the main thermal equipment in the foundry. It is used to melt pig iron lumps and overheat molten iron in order to obtain good quality molten iron.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality changxing refractory products 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!

Article Source:Classification of steel converters and refractory materials required
Company name: Henan Changxing Refractory Materials Co.,Ltd
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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
Company name: Henan Changxing Refractory Materials Co.,Ltd
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4 indicators that determine the high temperature performance of refractory materials

 During use, refractory materials are subject to physical, chemical, and mechanical effects at high temperatures (usually 1000~1800C), which are easy to melt and soften, or are corroded, abraded, or cracked and damaged, causing the operation to be interrupted and stained contaminated materials.

The following are 4 indicators that determine the high temperature performance of refractory materials:

(1)Refractoriness .

Refractoriness refers to the temperature at which a material reaches a certain degree of softening under the action of high temperature, which characterizes the performance of the material against high temperature. Refractoriness is the basis for judging whether a material can be used as a refractory material. The International Organization for Standardization stipulates that inorganic non-metallic materials with a refractoriness above 1500°C are refractory materials. It is different from the melting point of the material, and it is a comprehensive performance of a mixture of multiphase solids composed of various minerals.

(2) Deformation temperature under high temperature load.

It also known as the refractory softening point under load or the refractory deformation temperature under load, it means the resistance of the refractory to the combined action of high temperature and load under a constant load or the temperature range in which the refractory exhibits significant plastic deformation. The maximum use temperature of the refractory material can be inferred from its softening temperature under load.?

(3) High temperature volume stability of refractories.

Refractory materials produce volume expansion under the action of high temperature for a long time, which is called residual expansion. The size of the residual expansion (deformation) of refractory materials reflects the quality of high-temperature volume stability. The smaller the residual deformation, the better the volume stability; on the contrary, the worse the volume stability, the easier it is to cause deformation or damage to the masonry.

(4) Thermal shock stability.

The ability of refractory materials to resist sudden changes in temperature without being damaged is called thermal shock stability. This performance is also called thermal shock resistance or temperature sudden change resistance. Generally speaking, the greater the linear expansion rate of the material, the worse the thermal shock stability; The higher the thermal conductivity of the material, the better the thermal shock stability. In addition, the structure of the refractory material, the particle composition and the shape of the material all have an impact on the thermal shock stability.

Article Source：4 indicators that determine the high temperature performance of refractory materials
Company name: Henan Changxing Refractory Materials Co.,Ltd
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Tundish lining construction and refractory material composition

 The tundish is a transition device for molten steel between the ladle and the mold.

The main tasks of the intermediate package are:

(1) Diversion of molten steel. For the multi-stream continuous casting machine, the molten steel is distributed to each mold through the tundish;
(2) Steady flow. Reduce the static pressure of the molten steel, maintain a stable liquid level in the tundish, and smoothly inject the molten steel into the mold;
(3) Store molten steel. When replacing the ladle with multiple furnace continuous casting, the drawing speed is not reduced, creating conditions for multiple furnace continuous casting;
(4) Purify molten steel. In a long pouring time, the temperature of the molten steel is basically unchanged, and the inclusions in the molten steel are further raised to prevent the molten steel from contacting air and avoid oxygen and nitrogen absorption.?

The tundish is lined with refractory materials, and generally includes the following parts:

(1) Insulation layer (10~30mm), this layer is next to the steel shell of the tundish, usually using asbestos board, insulation brick or lightweight castable. The best effect is aluminum silicate fiber felt, which has low thermal conductivity and is easy to build.
(2) Permanent layer (100 ~ 200mm), this layer is in contact with the insulation layer, and its material is generally clay brick. The overall permanent lining is the most common, and the castable is generally high-alumina or mullite self-flowing castable.
(3) Working layer (20-50mm), which is in contact with molten steel and is the key part. Nowadays, insulation boards or coatings are commonly used. Insulation panels are generally siliceous, magnesia, and forsterite; Coatings are magnesia, magnesia chromium, and magnesia calcium. The paint is sprayed mechanically or applied manually.
(4) Tundish well block is inlaid at the bottom of the tundish and used to install the tundish nozzle. The material is usually high aluminum.
(5) The material of the bottom of the package is basically the same as that of the working layer. The working layer of the tundish bottom is easily damaged by the impact of molten steel and requires corrosion resistance and wear resistance. Generally, high alumina bricks or dense high alumina bricks and aluminum chrome bricks are used. Special large high-strength tar magnesia bricks are also used. The impact part of molten steel is reinforced by stony bricks or prefabricated blocks.
(6) The cover is covered on the tundish, which can play the role of heat preservation and splashing of molten steel. The material is made of clay or high-aluminum castable.
(7) Slag retaining wall (weir), which is built in the tundish and can be a single wall or a double wall. The material of the slag retaining wall weir is usually high-alumina bricks, but can also be made into prefabricated blocks, and its purpose is to block. In order to improve the cleanliness of molten steel, a molten steel filter can be installed on the slag retaining wall.
We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality refractory products 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!

Article Source：Tundish lining construction and refractory material composition
Company name: Henan Changxing Refractory Materials Co.,Ltd
More refractory products: https://www.cxrefractories.com/en-product-solution
Email:info@cxrefractories.com
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Corrosion mechanism and protection of BOF lining

 BOF smelting is a series of physical and chemical reaction processes under high temperature conditions. In this process, the furnace lining is corroded by a series of strong mechanical, physical and chemical effects. The main mechanism is as following,

1. Mechanical impact erosion.

The operations such as adding scrap steel and mixing molten iron directly face the large-surface furnace lining of the BOF, which produces strong impact, wear and erosion on the large-surface furnace lining, which are the main factors for the corrosion of the refractory lining of the furnace.

2. Physical effects.

During the smelting process, the airflow in the furnace scoured the furnace wall, the furnace cap and other refractory materials, the molten steel and slag melted and washed the furnace lining, and the high temperature reaction during the smelting process caused physical erosion of the furnace lining.

3. Chemical action.

The working layer of the BOF lining is generally made of magnesia-carbon bricks. The magnesia-carbon bricks contain a certain amount of graphitic carbon, which has poor wettability with the slag and can hinder the penetration of the slag into the brick body; the thermal conductivity is good and can greatly improve the thermal vibration resistance of the lining brick, so that the magnesia carbon brick lining life is longer. However, there is a strong oxidizing atmosphere in the BOF furnace. During the smelting process, high-temperature oxidizing gas will oxidize and remove part of the carbon in the brick, causing the brick structure to become loose and brittle, which will be lost and eroded by the flue gas and fluid.

Article Source: Corrosion mechanism and protection of BOF lining
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
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The difference between AOD furnace and ordinary converter

 1. AOD generally uses side and bottom combined blowing, and ordinary converters generally use top and bottom combined blowing;

2. AOD furnace also has top and bottom blowing;
3. The ordinary converter plays the role of removing carbon and adjusting other components in the process of making ordinary steel. Generally, the molten iron comes out of the converter as molten steel;
4. AOD furnace is mainly used for the continuous refining of ordinary molten steel, and is often used to smelt stainless steel and low carbon steel;
5. For the first decarburization in the converter, one of the main contradictions in stainless steel smelting is that it can decarburize while retaining chromium during further decarburization. AOD and VOD retain chromium in different ways.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality refractory products 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!

Article Source:How to choose refractory bricks for industrial furnace
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: info@cxrefractories.com
Website:http://www.cxrefractories.com

Causes of erosion of blast furnace body and selection of refractory materials

 

Erosion reason	Requirements for refractory properties
1.Wear of charge drop process	1.High crushing strength
2.Erosion wear of upward gas flow	2.The performance of alkali resistant metal corrosion resistance is good
3.Alkali metal erosion	3.Low porosity
4.Destruction of CO	4.Low iron oxide content
The upper and middle furnace refractories for blast furnace are: clay brick, sillimanite brick, dense clay brick, high alumina brick etc.
The lower part of the shaft, belly erosion causes
Erosion reason	Requirements for refractory properties
1.Chemical erosion of primary slag	1.Slag resistance is good
2.Wear of down charge	2.The performance of alkali resistant metal corrosion resistance is good
3.Erosion of metallic iron	3.High - temperature strength
4.Erosion wear of gas flow	4.Good thermal conductivity
5.Spalling due to thermal shock	5.Low porosity
?	6.Good thermal shock stability
From the waist to the lower part of the shaft lining, thermal shock is decreased by high temperature and high pressure gas charge and increase the wear and temperature changes, but also by the chemical high FeO high basicity slag erosion, more serious is alkali metals and zinc vapor caused by carbon deposition and chemical reaction, the refractory brick organization embrittlement lose strength. And suitable for refractory brick is: aluminum brick, silicon carbide, hot pressing small carbon bricks and semi graphitized carbon - silicon carbide brick.
Lining erosion reason
Erosion reason	Requirements for refractory properties
1.Corrosion and penetration of molten iron	1.Resistance to molten iron corrosion, good permeability
2.Circulating erosion corrosion of molten iron	2.Good thermal conductivity
3.Alkali corrosion	3. The performance of alkali resistant metal corrosion resistance is good
4.Destructive effect of thermal stress	4.Low porosity , microporosity
Hearth wall masonry taphole above by erosion of iron, iron mouth following the "dead iron layer", by the iron soaked, by erosion of molten iron flow in the furnace wall and the bottom of the junction. The masonry has good anti erosion ability of slag, molten iron and mechanical washing. Most of the hearth and bottom of large and medium blast furnace are made of carbon brick and carbon brick ceramic cup composite hearth.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality 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!

Article Source:Causes of erosion of blast furnace body and selection of refractory materials
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: info@cxrefractories.com
Website:http://www.cxrefractories.com

The properties of refractory materials

 Refractory inorganic nonmetallic material category, is the indispensable basic material, high temperature industry is mainly used in steel building materials non-ferrous machinery petrochemical industry the development of these industries are inseparable from the progress of refractory, refractory industry has become the fundamental guarantee of the national economy development, the escort for the steady development of high temperature industry in recent 20 years,?refractory material?industry of China is rapid development, has become the world's largest refractories production and consumption power, but also become the world's largest exporter refractory The increasing demand for?refractory materials?directly stimulates the rapid development of upstream?refractory?raw materials, and the reprocessing of raw materials is also an important development direction in the future.

Refractory mainly composed of magnesite bauxite, graphite alumina silica and other inorganic nonmetallic materials, plus a certain amount of additives, through a certain proportion of the allocation of inorganic nonmetallic?materials in the refractory?field is very widely used, huge refractory demand for inorganic nonmetallic materials has brought a broad market space.

Article Source:The properties of refractory materials
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
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Website:http://www.cxrefractories.com

Which refractory materials are used in the intermediate frequency furnace?

Refractories used in intermediate frequency furnaces are mostly dry, such as dry ramming materials, also called knotting materials. According to their chemical properties, refractory materials include neutral, alkaline and acidic materials. Induction furnaces, etc., select suitable refractory materials according to the characteristics of the furnace and the environment.　　

For the lining of the intermediate frequency furnace for melting cast iron, generally cheaper quartz sand is used as the knotting material. When the smelting temperature is high and the smelting conditions are relatively harsh, the service life of the quartz sand knotting material will be greatly reduced, which cannot meet the user's requirements. At this time, it is necessary to use dry knotting materials such as magnesia, magnesia aluminum, magnesia chromium, etc. (that is, the alkaline lining material that everyone often calls).

What are the common molding methods for refractory materials:

There are many molding methods for refractory materials. Common molding methods include extrusion molding, vibration molding, extrusion molding, ramming molding, isostatic pressing molding, melting casting molding, grouting molding, etc. The choice of forming method is mainly based on the nature of the mud, the shape, size and other process requirements of the embryo body. Except for the fact that most refractory materials are formed by press forming and vibration forming is used to form large shaped blanks. Extrusion molding is generally used For the forming of tubular blanks, grouting is generally used for forming hollow thin-walled blanks. Isostatic pressing is currently mainly used in the production of high-performance refractories.

Of course, the choice of molding method is also restricted by the equipment conditions of the production plant, so some products can't use the molding method. In this case, the company should choose other more suitable molding methods on the premise of meeting the technical requirements of the product.

Intermediate frequency furnace refractory knot forming method:

1. The sand should be manufactured according to the regular particle size and mixed evenly with additives. If you choose wet knotting, you can add 1% to 2% of the water, mix and put it for 1 to 2 hours before use.

2. Spread asbestos cloth on the inside of the sensor.
3. Knotted at the bottom of the furnace. After adding the sand material in batches, repeat the tamping with a pointed steel drill with a diameter of 12 to 14 mm each time. The furnace bottom knotting and feeding times are 4 to 5 times. The thickness of the furnace bottom is generally knotted to a regular height, and each knotting time is at least 10 minutes.
4. Put in the crucible core, which is the mould that controls the shape and volume of the crucible.
5. Knotted at the furnace mouth.

Article Source:Development of VOD ladle lining refractories

Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd

Email: info@cxrefractories.com

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Construction of Converter Refractories

The converter is an upright cylindrical smelting furnace that does not require an external heating source and mainly uses liquid pig iron as a refractory raw material for steel making. According to the nature of the furnace lining refractory, it is divided into two types: acid converter and alkaline converter. According to the part of the gas blown into the furnace, it is divided into a bottom blowing, a top blowing, a side blowing and a top-bottom composite blowing converter. Bottom blowing, top and bottom composite blowing converter bottom design breathable fire bricks. When laying, you need to locate the position of the ventilation bricks. The bottom blowing and side blowing blowing furnace bottoms are not designed with ventilated bricks, and the bottom of the furnace is relatively simple.
According to the bottom drawing of the converter, the production of magnesia carbon bricks for the bottom of the furnace is arranged, and each type of brick is used for production. The center brick of the bottom is processed bricks. According to the physical and chemical indicators of the design materials, the appropriate magnesia carbon bricks are selected for bonding processing. After processing, the cross reference line shall be drawn on the plane of the upper part of the center brick to provide a reference for positioning the ventilating bricks in the subsequent pre-laying and determining the position of the steel side and the steel side.
Breathable bricks need to be pre-made models. The model is generally made of wood. If the size is too small, it can be replaced by other refractory materials such as magnesia carbon brick. When processing ventilated bricks, special attention should be paid to technical indicators such as slightness, diagonal difference, and distortion. The dimensional deviation of the permeable brick directly affects the masonry of the steel mill. When making a ventilated brick mold, the dimensional tolerance should be controlled as a negative rule as much as possible. If it is a square rule, the steel factory may have a large gap around the ventilated brick.
In addition to the above refractory materials, it is also necessary to prepare sand at the bottom of the furnace (3mm-1mm), grinding tools, cutting machines, rubber hammers and other auxiliary materials.
Article Source:Construction of converter refractories
Company name:Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: sales1@chinafirebrick.com
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Development of ladle lining refractory materials

20th Century 50--70 years, China's steel plants mainly used aluminosilicate refractory materials, including clay, alumina brick and so on. Since the 1980s, China has successively developed the aluminum-magnesium carbon, coal quality calcium and magnesium and other several series of new steel package refractories. Wherein the aluminum-magnesium carbon refractory materials are of varieties, all specifications, is China's major ladle refractories.
In earliest 20th Century 50--60 years, a variety of clay bricks were mainly used in our country. Due to low cost, until the 1980s, some steel plants were using clay bricks as ladle lining material. Although clay brick is no longer used as ladle material so far, it had made a great countribution for recovery and future development of China's steel industry in the early days.

With the continuous development of steelmaking technology, steel quatity and quantity, clay bricks was no longer used because of short service life. Some of our mills started using a variety of high alumina bricks as ladle lining material, in which way the ladle life got a greatly improvement.

With the continuous improvement of steelmaking technology, high aluminum ramming mass, wax brick, alumina magnesia, aluminum-magnesium casting material, aluminum-magnesium unfired brick, aluminum-magnesium spinel castable, aluminum MgO-C, magnesium aluminate spinel brick, aluminum-magnesium unfired brick and a series of high-grade refractory materials appeared to adapt to higher demand.

Changxing refractory provides refractory products, calcium silicate products, castable & mortar, china refractory brick, ceramic fiber felt, ladle & tundish nozzle, ceramic fiber with high quality for you. Such as high alumina refractory bricks, magnesia carbon brick, clay refractory bricks and other refractory products.

Article Source:Development of ladle lining refractory materials
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: sales1@chinafirebrick.com
Website:http://www.chinafirebrick.com/