The details of HP Graphite Electrode

High power graphite electrodes refer to the graphite electrode that allows the use of a current density of 18 ~ 25A / cm2.
Graphite electrode has good electrical properties and chemical stability. What’s more, graphite electrode has advantages of high mechanical strength, low impurity content and good vibration resistance. Graphite electrodes are good conductors of heat and electricity. Graphite electrode is widely used in steelmaking electric furnace, refining furnaces, production of ferroalloy, industrial silicon, yellow phosphorus, corundum , submerged arc furnaces and other smelting furnaces that produce high temperatures by electric arc.
According to the different of service power and electricity , using different raw materials and production technology, graphite electrodes can be divided into ordinary power (RP) graphite electrodes, HP graphite electrodes, ultra-high power (UHP) graphite electrodes.?

Application:

High power graphite electrode is mainly used in high-power electric furnace and ladle furnace.
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.
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The working mode of moulding powder

Moulding powder forms ”three layers”?in the crystallizer, powder layer, sintered layer and slag layer. This working mode is the key to play the role of moulding powder.

The casting powder (1100~1200℃ melting point) on the surface of the molten steel (1500℃), heated by the molten steel and forms slag layer with 10-15mm thickness on the surface of molten steel. With the heat transfer slowed down, the moulding powder above slag layer sintered, forms sintered layer (900-600℃). And the casting powder above the sintered layer will gets fewer heat transfer, less than 500℃, so this is the powder layer. And the moulding powder covers in the molten steel surface evenly, to prevent cooling and secondary oxidation of molten steel.

During casting, the slag film between crystallizer and solidified slab shell could reduce the casting resistance and improve the heat transfer of crystallizer. As casting going , the slag layer is consumed constantly, then sintered layer becomes slag layer, powder layer becomes sintered layer, and adds more moulding powder into the crystallizer, makes the moulding powder keeps “three layers“.

Article Source: Moulding powder
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
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Reasons for mesh cracking of high alumina bricks

In addition, high alumina bricks on the surface of the network cracks generated in the gap between the brick brick surface. Therefore, it can be inferred that when the excess air coefficient in the kiln is small or the reducing atmosphere is generated, the CO is easy to be retained in these places due to the smaller slit, so that the Fe2O3 in the product is reduced to FeO; the surface of the channel is smooth , So it will not be affected by changes in the atmosphere, no network cracks. It is important to note that frequent changes in the nature of the combustion atmosphere should be avoided during the firing process. So that this alternating change will cause the surface to be damaged.
The chemical analysis of the surface and the central part of the products with high surface cracks in the surface of the high alumina refractory bricks shows that the Al2O3 on the brick surface is 1% -2% higher than the central part and the SiO2 is 1% -2% Center more than 10 times higher. It was found that the content of mullite was 12% lower than that of the central part, 4% -5% in corundum and 7% -8% in glass. This indicates that during the migration of Na2O, Na + volatilizes and adsorbs on the surface of high alumina brick, which will promote the decomposition of mullite, reduce the mullite on the surface of the product, and increase the corundum and glass phases. As the surface of the liquid phase increased and early appearance, so that the brick surface premature contraction, resulting in the production of reticulation.
Practice shows that in order to avoid and reduce the high aluminum brick surface network cracks, 1.2. High bauxite clinker water absorption were controlled at 4% -5% below, the tube of water absorption should also be controlled at 5.5 % Below, the excess air coefficient control between 1.1-1.2 is appropriate, so that high alumina brick firing in a stable weak atmosphere.
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Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
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How to distinguish the quality of high alumina bricks

High alumina brick is mainly used in lining of blast furnace, hot blast stove, furnace top, blast furnace, reverberatory furnace and rotary kiln. In addition, high alumina brick is also widely used as the open - hearth furnace, pouring system plug, water - mouth brick, etc.

It is featured by good quality, high refractoriness, long service life, and it is the most widely used by the industrial furnace. As the quality of it deters the service life of furnace, it’s very important to distinguish the prime and common one, the following can be referred to choose the good high alumina bricks.

Firstly, color is important for high alumina bricks, the prime one has smooth apprearance, it’s yellow white, the four sides are flat, with no broken corners and no cracks.

Secondly, it’s better to weigh, on average, the weight of the first grade is about 4.5kg and the second grade is 4.2kg, the third grade is 3.9kg.
In all, hope those is helpful to choose the prime generality high alumina brick as per your application.

Article Source: How to distinguish the quality of high alumina bricks
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
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The reason of crack mesh high alumina brick

Changxing refractory shows the reasons for the high alumina refractory bricks to produce reticular cracks. It is reported that high alumina bricks often appear on the surface of the crack is the production of high alumina brick defects, the reasons for this network cracks often quite complicated. For example, the clinker content (especially R2O content), the amount of fine powder added, the critical particle size, the mixing quality of the clay, the humidity and the temperature of the green body, the shrinkage of the green body during the firing, Mulli petrochemical reaction and corundum recrystallization, etc., will lead to the surface of the refractory product produced reticulate. The sintering of high alumina brick is liquid phase sintering, the formation temperature of liquid phase and the amount of liquid phase, the firing conditions of the atmosphere is also an important factor in the surface network cracks.
The sintering degree and firing atmosphere of high alumina bricks and the volatiles present in the gas phase have a great influence on the surface crack of high aluminum products. Sintered bad clinker in the process of burning products continue to shrink, causing the product cracking and crack; at the same time sintering bad clinker, the second Mulli Petrochemical is not sufficient, in the process of burning products, clinker itself Mullerite is still continuing, which is caused by inconsistencies in the product of an internal factor, resulting in the number of products increased the number of cracks and the increase in the degree of cracking.
High-aluminum refractory products on the surface of the degree of mesh cracking with the clinker used in the water absorption is closely related. The greater the water absorption of clinker, the greater the degree of reticulation. When the clinker with the water absorption rate, the product in the firing process clinker itself to continue to complete the sintering process, products shrink larger, and uneven, and thus prone to cracking and reticulation. In addition, the firing atmosphere of the kiln is one of the causes of the network cracks in the high aluminum products. When the high aluminum products are fired, the atmosphere of the kilns is weakly oxidized and the excess air coefficient is controlled at 1.1-1.2. The practice shows that the surface cracks Excess air coefficient increases and decreases, but the excess coefficient of air fluctuations should not be too large.
Changxing refractory are mainly producing high alumina brick, high alumina refractory bricks, alkali resistant brick, castable, clay brick, insulation brick, light high alumina brick, low creep high alumina brick, high aluminum wear Brick, high aluminum lightweight insulation brick, clay insulation brick, if you have any need please contact us anytime.
Article Source: refractory fire brick
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The high temperature compressive strength of the refractory fire bricks

The high temperature compressive strength of the refractory brick china (abbreviated as HCS) refers to the maximum pressure (in MPa) per unit area of the material at high temperatures above 1000-1200 °C. The compressive strength of the refractory material generally varies with increasing temperature. From the normal temperature from the temperature rise, the intensity of a straight line down. Since then, some of the material continues to decline with increasing temperature; some materials rise as the temperature rises to a certain extent and rises to a maximum temperature at a specific temperature, followed by a sharp drop. The following figure is a number of commonly used china refractory brick high temperature compressive strength with temperature changes.
The change in the high temperature compressive strength of the refractory fire brick is controlled by changes in certain components, especially those in which the matrix or its bound phase occurs at high temperatures. In general, the sintered refractory raw material, which is entirely composed of crystal, is prone to plastic deformation due to its grain and grain boundaries at high temperature, especially when its loading speed is small, so that the strength decreases with the temperature reduce. When some of the crystal phase between the melting point at high temperature or the formation of melt, such as silica brick, clay brick and high alumina brick, the matrix is mainly composed of glass phase, with the temperature rise, the strength of such multi-phase material the microstructure decreases with temperature. When the temperature is further improved, due to the viscosity of the glass phase from brittle to toughness, so that the material between the particles more firmly, so that the strength was significantly improved. Then, as the temperature increases, the melt viscosity of the material decreases sharply, and the strength of the material decreases sharply.
Changxing refractory are mainly producing high alumina brick, high alumina refractory bricks, alkali resistant brick, castable, clay brick, insulation brick, light high alumina brick, low creep high alumina brick, high aluminum wear Brick, high aluminum lightweight insulation brick, clay insulation brick, if you have any need please contact us anytime.
Article Source: refractory fire brick
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Methods to masonry of boiler castable

There are several methods could be taken, to protect the boiler castable from being destroyed during masonry.
(1) The balance of refractory castable and water is important, adding not too much or too little water.
(2) Blended castable should be used within 30 minutes, and please add it to the certain depth and length at a time.
(3) Mold of it could be demolished after the castable is strong enough. The load-bearing form should be demolished when the castable reaches 70% of the strength. In order to facilitate stripping, pouring all the mold before pouring surface should be coated with a layer of oil.
(4) After the boiler masonry to have enough natural drying period, so that most of the refractory layer of water can be precipitated.
(5) Before the oven, the furnace lining material must have a certain natural strength (enough safety period) to carry out. Oven principle "should not be short, should be slow should not be fast."
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: Methods to masonry of boiler castable
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
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