Important characteristics of refractory bricks. Fireclay brick weight: technical specifications, standard in cm Types of fire-resistant building materials

Fireclay bricks for stoves and fireplaces: composition, types, characteristics

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When building a furnace or combustion chamber, it is important to understand that red brick is not the best option. This material is very practical and popular among users. However, under the influence of high temperatures, the clay from which this material is made can collapse. When the temperature regime reaches 1200 ° C, the clay begins to melt, and when it cools, it crumbles.

Refractory brick SHA-5

Considering the fact that an ordinary stove heats up to 800 ° C, ordinary red brick can be used to build its body. But for doors and cast iron stoves - it is not suitable. This is due to the fact that the heating of metal elements reaches a maximum, as a result, the brick is destroyed. In such cases, it is better to use refractory bricks for the furnace.

Refractories are divided into several types:

• basic;
• quartz;
• carbonaceous;
• alumina.

One of the variations of the alumina type is fireclay brick. Such material is widely used due to the fact that it tolerates temperature extremes well.

What are fireclay bricks made of?

As already noted, fireclay bricks are very durable and stable, withstand strong heat well, and are not afraid of temperature changes. These qualities are due to the composition of fireclay bricks and the technology of its production, which is based on the firing of a clay mixture with the addition of fireclay powder. As a result, when high temperatures affect the brick, it becomes a gray-brown or yellowish color, which is its hallmark.

The composition of fireclay bricks determines its performance characteristics. Based on the proportions of clay and powder, certain grades of material are distinguished. The method by which the material is processed, or more precisely, the period of time during which the bricks are baked, also has a significant impact.

In case of overexposure, a strong vitreous film will appear on the surface, which has the most direct effect on the strength of the brick - it will increase it. However, the fire resistance values ​​will be lower.

If it is not fired for a very long time, then such a material will absorb moisture well, but will lose its strength. That is why it is necessary to strictly adhere to equivalent proportions, the only way to get the most suitable brick for laying stoves and fireplaces.

In order to prevent the products from spreading during the firing process, they need to add a special refractory clay, called fireclay. In rare cases, coke powder, graphite or coarse quartz is added instead. As a result, different types of bricks with individual characteristics are formed.

The final result is directly dependent not only on the raw materials and the method of their processing, but also on the characteristics of the fuel for roasting and the resulting ash.

Fireclay bricks are produced in accordance with GOST 390-69, and depending on its purpose, the manufacturing method, weight and dimensions of the material will vary. The weight of fireclay bricks can vary from 2.5 to 6 kg. The parameters of strength, density, porosity of bricks also differ. There are uniform size standards that almost all manufacturers adhere to: 230x113x65 mm, 250x120x65 mm and 300x150x65. Such dimensions are the most suitable for construction.

Most often, the inhabitants prefer such markings: ShB #5, ShB #9, ShB #22, ShB #44, ShB #47.

Characteristics

For a better understanding, we present the main types of fireclay bricks.

It is important to know the physical properties of fireclay bricks:

• specific heat capacity: 0.87-1.01 kJ/(kg/k);
• thermal conductivity coefficient: 1.27-1.28 W/m*g;
• ultimate strength: 20-12 n/mm;
• fire resistance (maximum temperature that a brick can withstand: 1800 ° C).

Based on the above, it becomes clear that fireclay bricks are a good material that is suitable for any type of work.

Advantages and disadvantages

The key advantage of fireclay bricks is its ability to tolerate high temperatures well and retain heat for a long period of time. Due to these properties, such products are used for the construction of fireplaces, stoves, barbecues, chimneys, etc.

The stove fireplace is not only very efficient and productive, it is also very attractive in appearance.

Due to the natural sand color in the room where such a unit is installed, a comfortable and cozy atmosphere is immediately formed. Also, using fireclay bricks, you can come up with and implement interesting design solutions.

Design refractory brick oven

Also, the pluses include the size of the blocks - they exceed the dimensions of standard clay bricks. In this regard, the number of fireclay bricks required for construction will be less. For laying stoves, products marked ShB No. 5 and ShB No. 8 are most often used.

The weight of one fireclay brick is much less than that of a product made from ordinary clay. Due to this, the load on the foundation for the furnace becomes much less. Given the fact that the elements are laid on a thin layer of adhesive solution, the weight of the entire building becomes less.

To connect bricks, you can not use an ordinary cement-sand mortar, because. in this case, it will not be able to withstand the powerful heat. Be sure to use a specially designed temperature-resistant mixture.

In addition to the advantages, there are also shortcomings, which are more likely to be regarded as features. Fireclay bricks absorb moisture very strongly, which negatively affects the strength of the material. That is why stoves made of such material should never be installed in rooms with high humidity, for example, in a bathhouse.

If the stove, which is made of fireclay bricks, is not heated regularly, then soon it may begin to crumble. Such instability to freezing obliges to strictly observe the rules for the operation of such products.

Due to the fact that the described bricks have a high density, it is difficult to work with them - for example, it will not be possible to cut them with a hacksaw. To do this, you will need to use a grinder with a segmented diamond disc or bakelite discs for stone.

There is fireclay brick - not cheap, much more expensive than usual. However, due to the larger size, it will require much less. Due to the small weight, you will save on the foundation and transportation.

Refractory brick selection

Only professionals know how to choose really high-quality material. In order to simplify the task for the townsfolk, we decided to describe a brief instruction to help you decide on the choice of SB bricks.

1. The first thing to do is tap on it. If it was produced with strict adherence to technology, then you will hear a subtle sound. A dull sound indicates that the sample you are considering is hygroscopic, this property negatively affects strength and thermal conductivity. In order not to make a mistake in choosing and not to purchase low-quality material, be sure to pay attention to the sound. It should resemble the beating of metal objects.
2. The next step is to evaluate the bricks in appearance. It is important that they do not crumble or fall apart. Their texture should be uniform.
   

   Obvious flaws indicate that the technology was not followed exactly.

3. If you see a thin film similar to glass on the surface, then the brick has been in the oven for too long. And this calls into question its quality and also significantly reduces the adhesion with the solution.

Manufacturers

Today, many large manufacturers are engaged in the manufacture of fireclay bricks. Let's highlight the most popular:

1. Kondratievsky refractory plant. This enterprise is located in Ukraine, equipped according to all modern standards. The plant uses exclusively high-quality raw materials.
2. Ogneupor LLC is a domestic manufacturer that gained wide popularity back in the 30s of the twentieth century. She began to produce and produce fireclay bricks in the mid-1960s and to this day she occupies a leading position in this sector.
3. The Chasovoyarsky plant is another Ukrainian enterprise that has been successfully operating for over 100 years.
4. TD "Rosogneupor" - the plant is located near the Latnensky clay deposit. It was built in the 1930s. During its existence, it has changed many times, and is currently equipped with modern high-quality equipment necessary for the production of fireclay bricks.

In conclusion, it is worth noting once again that fireclay bricks are a quality material that is currently used for the construction of stoves, fireplaces, etc. User reviews indicate that a fireclay brick oven can effectively heat a house. When choosing such a material, be sure to pay attention to the label and manufacturer. If you find it difficult to choose, use the help of professionals.

Brazier, stove or fireplace, then only refractory bricks can become a material. There are several varieties of it, including diatomite, magnesite, carbon and quartz. However, fireclay bricks are distinguished by their properties, which are used in places with temperatures of the order of 1300 C.

This material has versatility. It tolerates sudden temperature changes when heated, demonstrates excellent thermal conductivity, does not react to alkalis and a number of other aggressive chemical compounds. Fireclay bricks also have an aesthetic function - products made from such material always attract the eye due to their variety of shapes (rectangular, arched, wedge-shaped and trapezoidal) and shades (from almost white to light brown).

Note: The darker the color of fireclay bricks, the better it is suitable for building a furnace firebox.

The disadvantages of fireclay bricks include the following:

• its porous material quickly absorbs moisture, which leads to an increase in weight, as well as a decrease in strength during the heating period;
• does not tolerate freezing well, so that with irregular use of the furnace it may begin to crumble;
• difficult to process, in particular, it is poorly cut due to its high density and requires the use of a special mortar during masonry.

Another serious disadvantage from the point of view of the consumer is the high price of fireclay bricks.

We decipher the marking

Fireclay bricks are produced according to GOST with dimensions of 230x113x 65 mm, as well as according to technical specifications, where, in accordance with modern standards, geometric parameters can change in any direction.

Refractory fireclay bricks come in different grades. So ladle, blast-furnace, double-sided end and cupola are used in production, but in private construction bricks with the marking ShA and ShB are used. Here the letter "Sh" denotes fireclay, and the letter "B" indicates the fire resistance class and indicates that the brick can be used at temperatures up to 1350 C.

Brick marked SB is the undisputed leader in the construction of stoves, fireplaces and barbecues for individual use. The standard dimensions of such a brick are ShB-5 and ShB-8. The numbers help you figure out the dimensions. So for ShB-5, the length is 230 mm, width 114 mm, height 65 mm. ShB-8 is larger: with a similar height of 65 mm, its length reaches 250 mm, and its width is 124 mm.

In addition to the above, fireclay bricks marked ShB-45, ShB-6, ShB-94 can also be found on sale. Each of these types has differences in dimensions. For example, ShB-6, with a length of 230 mm and a width of 114 mm, has a height of only 40 mm.

For proper distribution of the load on the foundation, before starting laying, you should take into account the weight of the refractory bricks. This indicator is different for each label. If we talk about the weight of fireclay bricks, then one of the lightest is ShB-6, which "pulls" only 2700 gr. The SHB-5 will be heavier with its 3400 grams, and the mass of the SHB-8 reaches a full 4000 grams.

Standard sizes become one of the criteria for choosing refractory bricks.

Note: When buying this building material, you should pay attention to the fact that the bricks are without chips, cracks and dents, with a uniform color.

In addition, when tapped with an iron object, a high-quality brick sounds loudly (a hollow sound indicates that the brick has been burned), and when struck with a hammer, it does not crumble, breaking up into large pieces.

When buying building materials on your own, make sure that they are properly stored - fireclay bricks should be placed on wooden pallets in a dry room with good ventilation. Proper transportation of refractory bricks is carried out in plastic packaging.

special solution

For laying refractory bricks, a special one is required. You can buy it or make it yourself. If you prefer a ready-made dry mix, then go to a hardware store and buy fireclay mortar. It is enough to add clean water to it and mix with a mixer or concrete mixer until a creamy consistency. Next, the mortar is allowed to brew for about an hour, and then it is stirred again, and only after that they begin to work.

A self-prepared solution of refractory clay and fireclay sand allows you to achieve high bonding strength of bricks. However, such a mixture requires a lot of time due to the need for long-term soaking of the clay.

Ground white kaolin or blue cambrian clay is suitable for refractory mortar. Before mixing the solution, the clay is soaked, completely covered with water, and left in this state for at least 12 hours (or up to three days) with regular stirring. Soaked clay is rubbed through a sieve with a mesh size of not more than 3 mm. Sand (chamotte or mountain) is sifted separately. After that, the ingredients are mixed in a ratio of one part clay to two parts sand.

Note: One hundred bricks need 40 gr. dry fireclay mortar, or three buckets of a solution prepared by oneself.

Secrets of craftsmanship: to increase the strength of a home-made solution, about 150 gr can be added to one bucket. table salt, and for plasticity - about 200 gr. liquid glass. However, we must remember that the same salt may later “come out” on the masonry with whitish stains. In general, a well-made clay-sand mortar will firmly hold fireclay bricks without any additives.

Chamotte brick is an excellent refractory building material. Its natural base consists of white refractory clay (kaolin), which, thanks to feldspars in its composition, has a fine dispersed structure. Therefore, the use of fireclay bricks is so common in the construction of fuel chambers, chimneys, stoves, fireplaces and other buildings that can often come into contact with flames and temperature changes. After all, such a brick can withstand the temperature of fire in furnaces of 1200 degrees.

Fireclay bricks are used for the construction of stoves and fireplaces, because they can withstand temperatures up to 1200 degrees.

In the industrial production of refractory bricks, powdered kaolin and refractory clay undergo a firing process until their elastic properties are completely lost. Sometimes coarse quartz sand, graphite or coconut powder can be added to the brick. The technology for the production of fireclay bricks must be observed correctly, otherwise, when it is overexposed, the properties will gain even greater strength, but the overexposed brick will become unsuitable for laying chimneys. If it is underbaked, then laying from such a brick will become impossible due to its loose structure.

Types and sizes of fireclay bricks.

During the firing process, kaolin white clay retains its natural white color up to a temperature of 1200 degrees. Above 1300 degrees, it blushes, then, with an increase in temperature, it acquires a brownish tint and a granular basis. This color is considered acquired during production, it will be stable during further use of fireclay bricks.

With the appearance of brown color, the shape of the product may also change. At the exit, it has the correct geometry of the bar, and due to its low weight, it does not significantly affect the load of the foundation.

General properties of fireclay bricks:

1. Release according to GOST 390-96, the specific gravity of one brick bar is from 3.4 to 4 kg.
2. It has the shape of a rectangle or a wedge-shaped and trapezoidal bar.
3. Durable, does not crumble when broken, but only breaks into large pieces.
4. The strength is 1700-1900 kg/m.
5. Resistant to open fire, able to withstand up to 1500 degrees of surface heating.
6. Great for holding and dissipating heat.

Table of properties of fireclay bricks.

Due to its ideal physical qualities, refractory bricks have a high cost. However, its masonry does not always require a huge number of units.

The weight of fireclay products may vary. It depends on the brands of the product. At modern construction enterprises, two grades of refractory bricks are produced: ShA and ShB. The thermal conductivity of the bricks depends on the weight: it will be higher with less weight, and, accordingly, the absorption of moisture and adhesion with the mortar will be better.

When laying chimney buildings using fireclay bricks, the use of an appropriate viscous mortar with a high degree of frost resistance is required.

Therefore, the involvement of professional stove-makers is necessary.

This is due to its strength and fire resistance. Fireclay brick weight, width, length and height are very diverse, which allows it to be used in the construction of fireplaces, stoves, chimneys, barbecues, fuel chambers, barbecues, and other structures that must withstand significant temperature changes and interact with open fire.

What it is?

Fire-resistant brick briquettes are used both for household and industrial purposes.

Chamotte brick is a building material that is made from kaolin - white refractory clay with a fine dispersed structure, as well as with the addition of specific impurities, coconut powder, coarse sand and graphite. It is possible to obtain briquettes by firing refractory dust and fireclay powder at high temperatures. The main characteristics of this type of brick blocks:

• Diverse shape:
  • wedge-shaped;
  • rectangular;
  • trapezoid;
  • arched.
• Light weight:
  • from 3.4 to 4 kg.
• Variety of brands:
  • general application - ShA, ShB (the most popular standard ShB 5 and large ShB 8);
  • cupola furnaces - ShAV;
  • bilateral facing - ШЦУ;
  • bucket - ShKU;
  • blast-furnace for furnaces - broadband access;
  • others - PB, PV, SHAK, ShV, ShUS.
• Different Models:
  • porous;
  • dense.
• Wide range of colors:
  • from white to light brown.

The color of the defective material will differ from the quality.

If production technologies are violated in the manufacture of fireclay bricks, then such material loses its properties. You can recognize low-quality products by paying attention to their appearance. Violation of technology will not be limited to visual defects, such a brick will be less durable and will absorb moisture. Manufacturing defects are evidenced by:

• the presence of a vitreous film on the brick;
• color change to dark brown;
• the presence of cracks.

Properties of refractory brick blocks

Characteristic features of fireclay bricks:

• It does not exert a significant load on the foundation of the building due to its small dimensions and the fact that it weighs little.
• Strength. Able to withstand loads from 1700 to 1900 kg/m.
• Keeping warm for a long time.
• Excellent adhesion to mortar.
• Lack of a reactive response to the aggressive effects of chemical elements, alkalis.
• Fire resistance even with an open flame. Withstands surface heating up to a temperature of 1300-1500 degrees.
• No cracks on high heat.
• High degree of heat transfer.
• Use the minimum amount of mortar when laying.

In addition to positive qualities, refractory fireclay bricks also have negative ones.

Those who have already purchased building bricks in order to build a structure from it with their own hands (a house, a garage, a fence) have an idea about the classification of this building material (silicate, ceramic). They know what, for example, a double sand-lime brick M 150 is according to standards.

Photo: the most popular refractory material is fireclay

They can say that since it is double, then its geometric dimensions are 250 mm x 120 mm x 138 mm. And the brand - "M 150" is its strength indicator and indicates that this silicate building material can withstand a load of 150 kg per 1 cm2.

Standards, regulatory documents

Anyone who is interested in more complete information on the topic, standards on refractory materials used by man in construction (laying stoves, fireplaces) today, can familiarize themselves with the following regulatory documents:

• GOST 8691 - 73 "Refractory products for general purposes".
• GOST 24704 - 81 "Refractory corundum and high alumina products".
• GOST 390 - 96 "Refractory fireclay and semi-acid products of general purpose and mass production."
• GOST 24704 - 94 "Refractory corundum and high alumina products".
• GOST 4157 - 79 "Dinas refractory products".
• GOST 5040 - 96 "Refractory and highly refractory lightweight heat-insulating products."
• GOST 21436 - 75 "Refractory and highly refractory products for lining rotary kilns".
• GOST 6137 - 97 "Refractory aluminosilicate mortars".
• GOST 969 - 91 "Aluminous and high aluminous cements".

Refractory bricks

Ordinary building bricks, depending on the raw materials used in its production, are divided into:

1. Ceramic- which is made of clay.
2. Silicate- it uses a mixture of sand and lime, other additives.

But, these products of brick production can not be used everywhere. For example, with high-temperature technologies (up to 1800 degrees C) in the metallurgical industry, in glass-making (glass-making) industries, the same ordinary clay brick (in the common people, “red”) will not withstand high temperatures for a long time.

With strong heat and prolonged exposure to high temperature, it will begin to melt, and then, as it cools, it will crumble. Although, as a masonry and finishing material, it is widely used in indoor fireplaces and stoves in baths, saunas, residential areas, where the temperature is not higher than 800 degrees C.

Types of fire-resistant building materials

In furnaces where glass is blown, porcelain is fired, in blast furnaces where steel is smelted, a more resistant, fire-resistant material is used in the furnace core of hearths. Refractory bricks according to GOST 8691 - 73 withstand heat with a temperature of more than 1000 degrees C.

Refractories are produced with different properties and characteristics for different applications.

Fire-resistant material according to its physics - chemical composition, production methods and methods, temperature range is divided into four classes:

1. Aluminous.

Composition and applications of refractories

1. quartz brick- consists of quartz (sandstone), with small additions of clay. As a result of firing, it acquires a cavity-free, full-bodied structure. In furnaces it is used in places where it has contact only with an open flame (for example, reflective vaults in fireboxes of a fireplace, stove). Keeps heat well.

Important to remember! Quartz refractories should not be in contact with alkalis, lime, iron oxides, which destroy it.

1. - in a simplified form, it is compressed graphite or coke. It has the highest characteristics in terms of strength, fire resistance. It is used in highly specialized areas of construction (for example, in the construction of blast furnace structures).

1. - includes in its composition a lime-magnesian mass, which allows the use of this refractory for the production of Bessemer steel from phosphorus ores.

1. aluminous- from its very name it is clear that in its basis clay makes up most of the structural component (about 70%). Therefore, it is better (in contrast to quartz refractories) resists the destructive action of alkalis (lime). Easily tolerates rapid temperature changes.

It is easy to manufacture, its price is lower than other flame retardant materials. It is widely used in the cores of furnaces, where the temperature is not higher than 1300 degrees C. Brick of this grade is also called "chamotte". It is marked with the letter "W", and the numbers following it carry information about its size.

The nature of the heat treatment

In the production of fireclay material, according to the processing method, products are distinguished:

• unfired;
• burnt;
• fused cast.

Designation, shapes and sizes of fireclay products (GOST 390-96, GOST 8691-73)

The size of the refractory brick and its shape can be different. According to GOST alone, there can be more than a hundred such standard sizes.

Therefore, we present only the most used products in private furnace construction. The rest can be found in the standards themselves.

The brand of building material depends on the maximum temperature of its use during operation.

Table: Limiting temperatures for the use of fireclay products

Depending on the physical and chemical composition, the temperature of use, general-purpose fireclay refractories are divided into grades ShA, ShB, their serial number (1 - 109) depends on the shape and size. These brands are most widely used in private stove and fireplace construction.

For information! Fireclay refractories are also produced in other grades, fireclay ladle bricks ShKU, fireclay blast-furnace bricks for ShPD hearths and others.

In its form, fireclay bricks can be - straight, wedge rib, wedge end, trapezoidal, suspended and shaped. Here are tables of standard sizes, shapes of some brands of fire-resistant ideas widely used in laying stoves and fireplaces.

Table: Sizes and shapes of fireclay bricks for general purposes (grades ША, ШБ)

Designation, brand	Dimensions, mm
	230 x 114 x 65
	230 x 114 x 40	straight (bream)
	250 x 124 x 65
	300 x 150 x 65
	230 x 114 x 65/55	end wedge
	230 x 114 x 65/45	end wedge
	250 x 114 x 65/55	end wedge
	230 x 114 x 65/55	rib wedge
	230 x 114 x 65/45	rib wedge
	300 x 150 x 65/55 (65/45)	end wedge
	250 x 114 x 65/55	rib wedge
	230 x 114 x 65
	230 x 114 x 40
	250 x 124 x 65
	300 x 150 x 65	Tables: Straight fireclay Thus, fireclay products for standardization are divided into: wedge or straight (normal sizes), large or small formats; shaped large-block, especially complex, complex, simple; special fireclay products for industrial, laboratory purposes. Weight characteristics of refractory (chamotte) brick GOST 390 - 96 The weight of a refractory brick depends on the raw materials from which it is made, on its shape and size. How much does a refractory brick made of fireclay of the most popular brand (ША, ШБ), and its packaging (cages) without taking into account the weight of the pallet 30 - 40 (kg), look in the table below It will be interesting to look at the video in this article, how and with what you can make a figured fireclay brick with your own hands at the link: conclusions It will be easier with the selection of shapes and sizes of bricks if you purchase a ready-made ordered layout for standardized products. Then there will be no difficulty in processing the solid chamotte material with a diamond tool for the desired shape.