Measures to improve the life of electric arc furnace lining

 1. Selection of refractory materials.

Refractories for furnace building have strict standards for alumina content, bulk density, compressive strength at room temperature, flexural strength at high temperature and apparent porosity. Magnesia carbon brick has the characteristics of good corrosion resistance, good high temperature strength, long service life, etc., and is widely used in the construction of furnace linings.

2. Masonry of furnace lining.

The furnace lining must be of good quality. When laying bricks of various types of road linings, attention should be paid to leveling, the brick gaps should be controlled at 2-3mm, and the furnace door and steel tapping should be built in strict accordance with the requirements. In the early days, the furnace body mostly used air hammer to tie the tar magnesia lining as a whole. The working conditions of the workers were poor. At the same time, the lining had low bulk density, large apparent porosity, poor resistance to slag erosion and erosion, and severe slag line erosion during the smelting process. After switching to tar-magnesia sand combined brick masonry, not only the production process is mechanized and automated, and the bulk density is also increased from 2.3 to above 2.8. The slag erosion and erosion resistance are greatly improved, especially in the slag line and tapping. Near the mouth, the anti-erosion ability is obviously enhanced.

3. Reasonably determine the diameter of the pole center circle of the electrode.

The life of the furnace lining has a great relationship with the distribution of the electrode center circle (the circle made by the center of the electrode hole in a regular triangle). The diameter of the electrode center circle determines the electrode distribution position and the power distribution of the three-phase electrode, which has a greater impact on the melting rate of the charge and the life of the furnace lining. Increase the diameter of the pole center circle of the electrode, the electrode is close to the furnace wall, and the furnace lining will accelerate the corrosion rate under the high temperature of the arc, and the heating of the charge in the middle of the furnace body will be weakened; reduce the diameter of the pole center circle of the electrode, the steel material in the middle of the furnace body will be easier Local high temperature is generated, and the melting rate of the charge on the slope slows down. According to the experience of steel mills, when the diameter of the electrode circle is equal to 0.35-0.39 of the diameter of the melting chamber at the level of the furnace door, the life of the furnace lining is the best, and the minimum coefficient is used when the diameter of the melting chamber of the electric furnace is larger.

4. Optimize and strictly enforce the operating rules.

The life of the furnace lining is related to many factors and is closely related to the smelting operation. Incorrect smelting operation will shorten the life of the furnace lining. Including the strict power supply system to control the temperature of molten steel, charge processing and charging, popularize the foam slag process, rationally organize production, and shorten the smelting time.

5. Maintenance of furnace lining

Add an appropriate amount of light-burned dolomite to the charge to increase the MgO content in the slag, and increase the alkalinity of the slag to reduce the erosion of the furnace lining. Furnace repair is an important part of improving the life of the furnace lining, which can effectively reduce the loss of the furnace lining. Generally, the dry gunning method is adopted. After tapping, take the time to strengthen the gunning for severely corroded parts such as both sides of the furnace door, tapping mouth, and No. 2 slag line. Gunning mending is based on the principles of uniform mending, quick mending, and thin mending to improve the adhesion rate of gunning material, reduce heat loss, achieve good sintering effect and reduce furnace lining erosion. When there is a large area of potholes at the bottom of the furnace, the wet patch method is used, and brine or water glass is used as the adhesive. Timely maintenance of the furnace lining can effectively extend the furnace life.

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Article Source:Measures to improve the life of electric arc furnace lining
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Causes of damage to ladle purging plug

 1. Thermal stress.

The refractory material of the ladle purging plug working surface is directly in contact with the high-temperature molten steel, and is also subjected to the continuous blowing of the cold air flow, which generates a large temperature gradient, resulting in a high concentration of stress.

2. Scour, and wear.
The blown gas gives a certain reverse impact force to the refractory material of the ladle permeable brick working surface and its surrounding area.

3. Chemical erosion and steel clamping.
The material of the ladle purging plug reacts with the molten steel penetrating into the slit and the slag that has entered the working layer, which changes the physical and chemical properties of the working layer of ladle purging plug and increases the tendency of peeling.

4.Oxygen cleaning.
In the actual application process, thermal stress is one of the most important reasons for the damage of ladle purging plug.

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

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Factors influence MgO-C bricks quality

 Magnesia carbon brick is a high melting point basic oxide magnesium oxide (melting point 2800 ° C) and a high melting point carbon material which is difficult to be infiltrated by slag as a raw material, and various non-oxide additives are added.

A non-burned carbon composite refractory material combined with a carbonaceous binder. Ladle Magnesia carbon brick is mainly used for the lining of converter, AC arc furnace, DC arc furnace, slag line of ladle and so on.

The process factors affecting the performance of magnesia carbon bricks are mainly refractory raw materials, binders and additives.

1. Magnesite

The high-purity sintered magnesia was used in the original production of magnesia carbon bricks abroad. With the in-depth study of the use of magnesia-carbon bricks, the following reactions were observed at high temperatures:

MgO+C→Mg↑+CO↑

This reaction generally starts at 1650 ° C, and the reaction is intensified at l750 ° C. This is one of the important reasons for the loss during the use of magnesia carbon bricks, and it is also the reason why the loss of magnesia carbon bricks at 1700 ° C or above is significantly increased. The impurities such as SiO2 and Fe2O3 in the magnesia have a promoting effect on the above reaction, and therefore, it is desirable that the magnesia has a high purity.

Compared with sintered magnesia, fused magnesia has a more complete crystal structure and a more stable carbon reduction. Especially the characteristics of large-crystal fused magnesia are more prominent, so the production of magnesia-carbon bricks begins to shift. Fused magnesia. The fused magnesia-sintered magnesia may also be used in combination in consideration of the bonding state of carbon and the wett ability of the binder.

The results of the use of magnesia-carbon bricks show that the best effect is on the production of magnesia-carbon bricks with magnesia with high MgO content, large magnesia phase crystal particles and calcium-silica ratio greater than 2.

2. Graphite

Graphite is another essential component in magnesia carbon bricks. Graphite has good basic properties of refractory materials. The main physical and chemical indicators are: fixed carbon 85%～98%, ash 13%～2% (main component SiO2, Al2O3, etc.), relative density 2.09～2.23, melting point 3640K ( Volatile). Since graphite is very easily oxidized, it has not attracted much attention for a long time.

There are three reasons for the oxidation of graphite during the use of magnesia carbon bricks:
(1) Oxidation of graphite by oxygen in the air;
(2) Oxidation of graphite by oxides in the slag;
(3) Oxidation of graphite by impurity oxides contained in graphite itself. These oxides mainly refer to SiO2 and Fe2O3.

After the impurity oxide and graphite in the magnesia carbon brick react, the structure of the brick body is loose, the gas permeability is increased, and the strength is decreased, which is the internal cause of the damage of the magnesia carbon brick. Therefore, most of the magnesia carbon bricks used are graphites with high purity and large crystals of phosphorus.

3. Bonding agents

Bonding agents are essential for magnesium carbon bricks and other carbon-containing refractory products. There is no mutual solubility relationship between graphite and refractory oxide, and it is impossible to sinter each other.

They are cured by bonding at room temperature. The binder is coked and carbonized, and carbon is combined with graphite at high temperatures. Generally, the binder refers to organic substances such as resins and asphalt. The high-temperature coking of the binder forms about 3% of carbon after carbonization.

Although this amount is not much, it is the most dynamic component in magnesia-carbon bricks or other carbon-containing products, and has an important influence on the high-temperature performance of the product. Magnesia-carbon brick binders can be generally divided into three types: phenolic resin, modified asphalt, and petroleum cracking by-products. Among them, phenolic resin is the best used and the most used.

4. Additives

The oxidation of graphite is one of the most important causes during the destruction of magnesia carbon bricks. Due to the loss of carbon from oxidation, the structure of the brick body is loose and the strength is lowered. The damage process follows the path of oxidative carbon loss → structural looseness → erosion → erosion and dissolution.

In order to improve the oxidation resistance of the ladle magnesia carbon brick, a certain amount of additives may be added, including silicon powder, aluminum powder, FeSi alloy, CaSi alloy, SiC, Si3N4, B4C and the like. Another effect of the additive is to "bridge" between the refractory oxide and the graphite to form a strong bond between the graphite and the refractory oxide, which is facilitated by the formation of a new mineral phase at a certain temperature.?For further details, please feel free to contact us, we would be your reliable partner.

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:Factors influence MgO-C bricks quality
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Brief introduction of magnesia-carbon brick raw material

 1. Fused magnesia sand: it is an alkaline refractory made of natural magnesite, light fired magnesia or sintered magnesia fused by an arc furnace. Fused magnesia main crystal phase of periclase, melting point is 2800 ℃, 1600 ℃ sublimation in vacuum, in reducing atmosphere above 2000 ℃ sublimation, is greater than 3.40 g/cm3 density, porosity of 0% to 10%, 5.5 mohs hardness, resistance to basic slag erosion is very strong, stable chemical properties, under the high temperature of 1500 ℃ and other than the silica brick no or weak reaction between all kinds of refractory materials. The appearance should be clear after the complete melting crystallization, do not allow mixing with other magnesia or sundries.

2, Graphite: is a carbon as the main component of the natural mineral, it has high temperature resistance, heat conduction, electricity, lubrication, plastic and corrosion resistance and other properties. It is the main material containing carbon resistant material. The graphite used in refractory is flake graphite, which is divided into high purity, high carbon, medium carbon and low carbon graphite according to the fixed carbon content. The color is iron black, steel gray. The density is 2.09-2.23g/cm3 with a melting point of 3700℃±100℃(in vacuum), high thermal conductivity, small expansion coefficient, small elastic modulus, good lubricity, good conductivity, stable chemical properties, no reaction with acid, alkali and organic solvents at room temperature, and steel solution is difficult to wet, with good anti-erosion performance.

3. Phenolic resin: it is a non-aqueous organic binder for refractory materials. It is prepared by condensation of phenol (or cresol, dicresol, or resorcinol) with formaldehyde (or glycolaldehyde) under the action of catalyst.?

The main advantages are

(1) high carbonization rate (52%);

(2) good adhesion, high strength of the formed body;

(3) high bonding strength after burning;

(4) the rate of hardening can be controlled at room temperature;

(5) less harmful substances, can improve the operating environment.

According to heating properties or structural morphology classification, there are thermosetting phenolic resin and thermoplastic phenolic resin, according to product morphology classification, there are liquid phenolic resin and solid phenolic resin (granular and powder), according to the curing temperature classification, there are high temperature solidified type 130℃-150℃; There are medium temperature fixed type 105℃-110℃; There are room temperature solidified type 20℃-30℃.g material.

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:Brief introduction of magnesia-carbon brick raw material
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Application fields and advantages of refractory castables

 As a new type of refractory material, castable is mainly characterized by high fluidity and is suitable for monolithic refractories formed by casting. Compared with other monolithic refractories, it has higher binder and moisture content and is fluid. Because of its better performance, the application range of unshaped refractories is wider, and the materials and binders used can be selected according to the conditions of use. It can be directly poured into a lining body for use, and can also be used as a prefabricated block by pouring or vibrating method.

Refractory castables are developed on the basis of low cement series refractory castables, and are a type of refractory castables that have developed vigorously in recent years. Its varieties include high-tech, high-performance and high-purity refractory castables, chromium-containing, carbon-containing and micro-expansion refractory castables, etc., which are mainly used in steel smelting furnaces, ladles, tundishes, fluidized bed boilers and regenerative heating furnaces on thermal equipment, the service life is increased and good economic effects are obtained.

Refractory castables use high-quality, high-purity or synthetic refractory raw materials and additives, ultra-fine powder technology, excellent binders and high-efficiency additives. Under the guidance of the basic theory of refractory materials, according to the use and operating conditions of various thermal equipment, scientific formulate the material formula, precisely adjust the particle size composition, reasonably select the binder and admixture, and formulate the new technology refractory castable with excellent performance and longevity. Taking the high-tech refractory castable for ladle as an example, it is characterized by sub-combination, self-sintering, and self-expansion under high-temperature use conditions. The "three-self" principle is also embodied in different degrees in the new technology refractory castables, so its performance is excellent and the service life is significantly improved.

High-quality, high-purity or synthetic refractory raw materials are the basis for the preparation of new-tech refractory castables, and also the basis for the production of high-efficiency unshaped refractory materials. Such as tabular corundum, dense corundum, white corundum, corundum mullite, alumina-magnesia spinel, high-purity magnesia and spherical high-bauxite clinker. In addition, brown corundum, white corundum, sub-white corundum and aluminum-magnesium spinel are made from high-quality bauxite clinker and other raw materials after sintering or electric melting. Process treatment, its performance is excellent, can partially replace alumina-based synthetic materials, and is widely used.

The excellent performance of refractory castable means that its performance indicators are suitable for the use requirements of thermal equipment and can achieve the purpose of longevity. Without the longevity of the kiln, excessive pursuit of performance indicators is of no benefit.

The scope of application of new technology refractory castables is also defined. For example, ultra-fine powder combined with magnesia refractory castable is applied on the ladle slag line, and the effect is better, but as the anti-slag material at the bottom of the heating furnace, because the use temperature is about 1200 ℃, the sintering strength is not reached, and it is difficult to achieve good results. .

Refractory castable is a milestone in the history of the development of unshaped refractories. Its important sign is its entry into the high-temperature smelting furnace of steelmaking and ironmaking, and significant results have been achieved. In the future, according to the use and operating characteristics of the kiln and its thermal equipment, advanced raw materials, scientific formulas, reasonable grading, and elaborate production will be used to develop new high-performance and functional refractory castables to meet the needs of my country’s iron and steel industry. The need for rapid development.

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:Application fields and advantages of refractory castables
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Process technology introduction of tundish sizing nozzle quick replacement system

At present, the representative quick-change systems at home and abroad are:

(1) Comcast nozzle adjustment system (CNM);

(2) Danieli flying nozzle replacement system (FNC);

(3) Interstroke sizing nozzle replacement system (MNC);

(4) Kurosaki Harima Co., Ltd. Tundish Nozzle Online Replacement System (OTNC);

(5) Vesuvius calibrated nozzle replacement system (CNC).

Although there are many quick-change systems, there are two main ways to sum up from the replacement method:

The quick replacement methods are:

1.Hydraulic quick change method:

The in-use nozzle and the spare nozzle are placed on the same plane back and forth, supported by a high-temperature spring, and replaced with a hydraulic ejector method;

The quick replacement of the sizing nozzle adopts a specific mechanical device. There is a running slideway with an accurate size in the device, and the sizing nozzle and the spare sizing nozzle in the working state are positioned in the slideway.

When the sizing nozzle needs to be replaced, press the start button, and the hydraulic drive device pushes the standby nozzle to slide from the standby position to the working position within 0.1s, and the original working nozzle is pushed out to the collection position;

The molten steel is injected into the mold through the new nozzle, so that the sizing nozzle can be quickly replaced during the continuous casting process. After replacement, the deviation of the center line of the upper and lower nozzles is less than 0.1mm.

2. Manual quick change method:

The in-use nozzle and the spare nozzle are placed in a fan shape on the same plane, mechanically fixed, and replaced manually. The manual replacement mechanism is simple, divided into four parts: the base, the fixed plate, the sector plate, and the spring pressure regulator.

There are two sizing nozzles in the fan-shaped skateboard frame. Moving the handle of the fan-shaped frame can make the casting hole of one of the nozzles on the fan-shaped skateboard frame work, and the other nozzle has been moved to the other side of the device. Replace the removed nozzle brick.

The characteristics of the device are:

(1) The device has reasonable structure, simple structure, convenient maintenance and low labor intensity.

(2) Using a unique spring pressure regulator, there is a certain pre-pressure on the nozzle, which can quickly replace the new nozzle brick under the condition of continuous flow.

Article Source:Process technology introduction of tundish sizing nozzle quick replacement system
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Influence of silica micropowder on the hydration of calcium aluminate cement

 In most cases, silica powder is used together with cement and other binders. Silica powder has a higher surface area, which can provide more nucleation sites for the hydration products of calcium aluminate cement, which is beneficial to the crystallization of the hydration products, and improves the cementation between the castable particles, thereby increasing the castable Strength of Silica powder can change the hydration product composition of calcium aluminate cement.

Studies have shown that adding silica powder to the clay clinker castable combined with calcium aluminate cement and curing at 40°C can affect the production and conversion of calcium aluminate cement hydration products. Pure calcium aluminate cement is hydrated for 24 hours, and the production of β-C2AH8 and α-C2AH8 of its hydration products increases with the extension of curing time, but the production of α-C2AH8 gradually decreases after 24h. After adding silica powder to calcium aluminate cement, the production of α-C2AH8 and β-C2AH8 can reach the maximum after curing for 24 hours. After 24h, α-C2AH8 and β-C2AH8 were converted into calcein hydrate C2ASH8. Silica micropowder is collected by vapor precipitation in industrial production, and it contains a variety of alkali metal impurity elements inside, which makes it exhibit different chemical properties in aqueous solution, such as zeta potential and pH value. Some studies have shown that silica micropowders with different pH values in aqueous solutions have a greater impact on the hydration process of calcium aluminate cement (CAC).

With the increase of pH value (2.77, 6.91 and 7.66), silica powder can increase the hydration rate of calcium aluminate cement and promote the generation of hydration products. This may be because the higher the pH value of silica micropowder, the more OH- is ionized in the aqueous solution, which accelerates the "hydroxylation" process in cement hydration, thereby accelerating the hydration reaction of calcium aluminate cement and promoting the hydration products of cement are formed; When the pH value of the silica powder is low enough, the aqueous solution will dissociate more H+, and part of it will neutralize the OH- and hinder the "hydroxylation" process of calcium aluminate cement, thus Delayed the hydration rate of cement.

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:Influence of silica micropowder on the hydration of calcium aluminate cement
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Utilization status of discarded magnesia carbon bricks

 At this stage, the iron and steel industry has overcapacity. With the country's continuous strengthening of capacity reduction, the continuous deepening of supply-side reforms, and the increasing attention to environmental protection effects, energy conservation and consumption reduction have gradually become the key to the survival of iron and steel enterprises. The steel industry has a huge demand for refractory materials, and the annual output of waste refractory materials has reached 7 million tons. Among them, most of the refractory materials dismantled after use by steel mills are magnesia-carbon. Recycling it not only greatly saves production costs, but also achieves environmental protection and solid waste recycling. Therefore, the development and utilization of waste magnesia carbon bricks at home and abroad has been increasing. The current status of the utilization of waste magnesia-carbon bricks by domestic and foreign iron and steel enterprises is as follows.

1. Preparation of metallurgical auxiliary materials

As an important way of recycling economy for metallurgical enterprises, the recovery of waste refractory materials and the preparation of metallurgical auxiliary materials have developed rapidly. Domestic Company cooperates with Henan Company to combine waste magnesia-carbon bricks and some additives to make multifunctional magnesium balls, which can replace dolomite in full or part as slag-making auxiliary materials, which are the steelmaking, slag-making process and slag-splashing process of the converter creating condition.

2. Preparation of recycled magnesia carbon bricks

Baosteel uses waste magnesia-carbon bricks from the ladle slag line as raw materials, after sorting, removing surface inclusions, slag and oxide layer, hydration and other treatments, adding 3% to 4% thermosetting phenolic resin ingredients and mixing them at 200℃, 260MPa Recycled ladle magnesia carbon brick are made after hydraulic pressure and 5h curing treatment, the effect is similar to the use of new magnesia-carbon bricks.

3. Preparation of tundish dry materials

The main raw material of tundish magnesia dry vibrating material is fused magnesia. With the changes in market demand in recent years, its price has far exceeded the cost, making the production of magnesia dry vibrating material basically without economic benefits. This situation has promoted the development of the use of recycled magnesia-carbon materials to prepare tundish dry materials. Guangzhou Iron and Steel, Maanshan Iron and Steel, etc. have conducted related research.

Guangzhou Iron and Steel has carried out research on the partial replacement of mid-range magnesia with waste magnesia carbon bricks to prepare dry materials for recycled tundishes. The waste magnesia-carbon brick particles were used to partially replace the mid-grade sintered magnesia in the original composition for batching. After making the strip samples, the performance was tested. It was found that both the shaped and unshaped waste magnesia-carbon brick particles could be used for the dry material of the tundish, and the shaping was used. When granular, the overall performance is better.

4. Preparation of gunning material for ladle

The magnesia-carbon bricks disassembled from the steel ladle slag line of Shan Iron & Steel Co., Ltd. are treated as qualified raw materials after removing the surface slag and iron, crushing, removing iron, and sieving. Since Shan Iron & Steel's ladle gunning repairs the slag line of the red hot ladle, the water in the sprayed layer quickly evaporates due to the high gunning temperature, making Al4C3 too late to hydrate. Therefore, it is not necessary to hydrate the raw materials during the production process.

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:Utilization status of discarded magnesia carbon bricks

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Brief introduction of LRF delta castable

 Ladle is the main thermal equipment for loading molten steel. In the process of loading and transporting molten steel, due to the heat loss at the mouth of the ladle, many steel plants have chosen to increase the ladle roof to reduce the heat loss in recent years. There are many types of unshaped refractory materials for ladle lids, but the refractory castables used for ladle lids that can improve the use effect of ladle lids need to choose suitable castables according to the actual use environment.

The castable for ladle roof can choose high-aluminum mullite castable or low-cement steel fiber castable. High-aluminum mullite castable is to choose high-quality high-alumina bauxite as refractory aggregate, and add appropriate refractory powder according to the formula. The low-cement steel fiber refractory castable is a kind of refractory castable added with steel fiber. Steel fiber can improve the wear resistance and flexural performance of the castable. The low cement content can effectively improve the overall high temperature resistance of the castable. As the lining of the ladle roof, it can effectively resist the corrosion of molten steel gas and molten slag.

The ladle delta castable can be directly poured into the ladle roof mold during use. The high-alumina mullite castable has excellent high temperature performance, high compressive and flexural strength, and good volume stability. Because high alumina bauxite has good heat vibration performance, as the main raw material of the refractory castable for the ladle roof, can increase the service life and use times of the ladle, reduce the maintenance frequency of the ladle roof, effectively increase the turnover speed of the ladle, speed up the steelmaking production rhythm, and ensure the quality of molten steel. And production anterograde played an important role.

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

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:Brief introduction of LRF delta castable
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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
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Essentials of refractory construction for RH refining furnace

 RH system equipment is a secondary refining process equipment for molten steel used to produce high-quality steel. The entire molten steel metallurgical reaction is carried out in a vacuum tank with refractory lining. The lower part of the vacuum tank is two dip pipes with refractory lining, and the upper part is equipped with hot elbows. The temperature during refining in RH furnace is as high as 1600~1700℃.

Therefore, the lining refractories are required to have high fire resistance, can withstand the impact of maximum temperature and local overheating, and have a small amount of liquid phase at high temperatures, and can resist the erosion of low-viscosity slag. Alkaline bricks with high purity and direct bonding rate should be selected. The intermittent operation of HR will cause temperature fluctuations, and the material is required to have excellent thermal shock resistance. It is better to use magnesia carbon bricks and magnesia chrome bricks with the best thermal shock resistance.

In addition to selecting suitable refractory materials, construction is also the key to the service life of RH refining furnaces.

Ramming material construction: The bottom of the lower trough, the refractory bricks and the circumference of the circulation pipe are constructed with ramming material. Due to the high pressure, the ramming material is required to be compact, especially for some irregular shapes. A special hammer head is used for construction to ensure that the compactness of the ramming material meets the requirements.

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!

Article Source:Essentials of refractory construction for RH refining furnace
Company name: Henan Changxing Refractory Materials Co.,Ltd
More refractory products:https://www.cxrefractories.com/en-product-solution
Email:info@cxrefractories.com
Website:https://www.cxrefractories.com

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
More refractory products:https://www.cxrefractories.com/en-product-solution
Email:info@cxrefractories.com
Website:https://www.cxrefractories.com

Refractory castables and measures to increase their service life

 As we all know, refractory castable is a kind of amorphous refractory without calcining. It is made up of refractory aggregate, refractory powder and cement in a certain proportion; it has good fluidity after adding water and stirring during construction. Then it is formed and cured (to be baked according to a certain temperature system) to make it condense and harden. The use characteristics of refractory castables are as follows: First, the masonry structure has few joints, strong integrity, and good sealing. It can avoid the infiltration of clinker powder during application and operation; Second, it is easy to anchor and convenient to construct, which is beneficial to improve masonry. Efficiency and masonry quality; The third is that raw materials are widely used, which is convenient for comprehensive utilization of resources, and the delivery time is short, which can reduce inventory and related costs accordingly.

With the gradual expansion of the application of refractory castables, its life cycle has become the most concerned issue of all owners. In order to ensure the life cycle that meets the design requirements, the following aspects should be achieved: First, a strong manufacturer should be selected to ensure the quality of the refractory castable itself; Second, a reasonable selection and configuration should be carried out according to the use environment; It is necessary to have a reasonable construction plan and strict construction process control measures during construction, including proportioning control, molding quality control and reasonable maintenance, heating system control and so on.

Popularly speaking, refractory castable is a kind of high-temperature-resistant concrete, so it also conforms to the theory of concrete. For example, the amount of water added is the fundamental reason for controlling whether the refractory castable can achieve the design strength. However, driven by profits, some construction parties will add a lot of water to the castable in order to speed up the construction progress during the construction of refractory castables, resulting in the use of the kiln refractory lining after the construction is much lower than the design requirements , Even after half a year of use, serious problems have occurred and must be overhauled (and for well-constructed refractory castables, there is no need for overhaul after 3 to 5 years of use). We know that refractory investment accounts for a small proportion of the entire plant investment (about 2% to 4%), but its impact on the future operation of the entire system is very large. The loss due to a refractory lining accident for a day of stopping can be as little as hundreds of thousands or even millions. Therefore, ensuring the high operating rate of the firing system can achieve the high-quality, high-yield and low-consumption operation of the system. Therefore, the construction process control of refractory castables is particularly important. Usually we should strictly follow the following regulations.

First, the amount of water added to the castable should be strictly controlled in accordance with the instructions for use, and should not exceed the limit. On the premise of ensuring the construction performance, the amount of water added should be less than more.

Second, the mixing time of the castable is not less than 5min. When operating, use a compulsory mixer. When mixing, dry mix first, and then add 80% of the amount of water to stir. Then, depending on the degree of dryness and wetness, slowly add the remaining water and stir until Obtain a suitable working consistency.

Third, the pouring material poured into the mold frame should be immediately stratified with a vibrating rod. The height of each layer should not be greater than 300mm, and the vibration spacing should be 250mm. When vibrating, try to avoid touching the anchors and not damaging the heat insulation. Do not vibrate and re-vibrate on the same part for a long time. After seeing the reflow of the castable surface, the vibrating rod should be slowly withdrawn to avoid segregation and voids in the castable layer.

Fourth, when pouring a large area, the construction should be divided into blocks. The pouring area of each block should be about 1.5m2. The expansion joints should be set according to the design and should not be omitted. The expansion joints should be set in the middle of the anchor interval.

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

Article Source:Refractory castables and measures to increase their service life
Company name: Henan Changxing Refractory Materials Co.,Ltd
More refractory products:https://www.cxrefractories.com/en-product-solution
Email:info@cxrefractories.com
Website:https://www.cxrefractories.com