Equal-flange bent steel channels (table, assortment, dimensions and reference values)

Bent channel is a metal product in demand in many industrial sectors. Widespread application requires compliance with technical standards to ensure industrial safety and high quality of finished products. When choosing a supplier, it is important to make sure that the channels in all respects fall within the regulatory standards and conditions.

All requirements are given in the document GOST 8278-83. Despite the simple form and manufacturing process, the product must pass control in many respects. To do this, the bent channel, the assortment of which is given in the document, is checked against the specified size tables.

Manufacturing and classification

Channels are made of steel of various characteristics. The basis can be:

• ordinary quality material;
• low alloy steel;
• highly resistant to corrosion.

The blanks are steel sheets for roll forming machines.

Determines the assortment of bent channel GOST 8278-83 or 8281-80. In the first case, equal width of the shelves is assumed, and the product is classified as equal-flange (examples are in the Metalbaza catalog of channels). The second document describes products with shelves of unequal width.

Explanation of hot-rolled channel markings

These metal products are manufactured in accordance with GOST 8240-97. In its marking, after the name of the metal product (“Channel”) there is a number indicating the height of the wall in centimeters. The size range is 5-40 cm. This indicator is also called the product number.

After the size in the designation there is a letter characterizing the design features:

• U - the internal edges of the shelves are located at a slope to each other, the slope is 4-10%;
• P – internal edges are located parallel to each other;
• L – lightweight type of rolled product, internal edges are parallel;
• E – economical series, also refers to products with parallel internal edges;
• C – special series, has sloped edges.

After the letter characterizing the design features of the rental, the accuracy of the rental is indicated through a hyphen. “B” – normal accuracy, “B” – increased rolling accuracy. Between the first number and the letter designating the structure, there may be a small letter “a”, which indicates the increased width and thickness of the shelf. At the end of the marking, GOST is indicated, to which the product range corresponds.

An example of designating dimensions and other characteristics of a hot-rolled channel: Channel 24L-B GOST 8240-97. This means that the product has a wall height of 240 mm, belongs to the light series, the rolling accuracy is increased, and the product properties comply with GOST 8240-97.

After the characteristics of the channel itself, the grade of steel from which it is made is indicated through a fraction, as well as GOST, which regulates its production. For example:

24L-B GOST 8240-97/St3sp GOST 535-2005. This metal product is made of carbon steel of ordinary quality, grade St3, the degree of deoxidation is “calm”. In the production of U-shaped hot-rolled steel, high-quality structural and low-alloy steels can also be used.

Application

The main areas of application of the product are construction, repair and finishing work. Examples of using:

• reinforcing frame elements;
• hanging frames;
• reconstruction of old buildings - low weight allows you to remove excess load on the foundation;
• finishing of internal and external walls;
• design of partitions in residential and industrial buildings;
• assembly of stands for repair or testing work.

The main advantage of the part is its ability to withstand high mechanical loads and bending pressure with low weight. This is achieved by a combination of the characteristic shape and material of manufacture. The flat profile ensures high compatibility with flat surfaces, making it easier to install the channel.

Varieties by size

The range of bent channels has been officially regulated since 1984. Due to the ease of production, there were practically no significant changes in the document. The first edition with tables of bent channel sizes was published in the USSR under the number 8278-75, with the release of the current GOST it was declared obsolete and invalid. The basic requirements for domestic manufacturers remain the same as 30 years ago.

Compliance begins with the selection of raw materials for production. Bent channel is made of cold-rolled and hot-rolled steel, supplied in the form of rolls. It is passed through profiling machines; The accuracy of the procedure is determined by three categories:

• A - high;
• B - increased;
• B - normal.

The first two types are recognized as products of the highest quality category.

Bent channel GOST 8278-83

INTERSTATE STANDARD

Valid from 01/01/84

until 01/01/99

1. This standard applies to steel bent equal-flange channels manufactured on profile bending mills from cold-rolled and hot-rolled, coiled steel of ordinary quality, high-quality carbon structural and low-alloy steel.

The technical level indicators established by this standard are provided for the highest and first quality categories.

(Changed edition, Amendment No. 1, 2).

1a. According to the accuracy of profiling, channels are manufactured:

high accuracy - A;

increased accuracy - B;

ordinary accuracy - V.

The requirements for high and increased profiling accuracy correspond to the highest quality category.

(Introduced additionally, Amendment No. 1).

2. The verification section of the channels must correspond to that shown in the drawing.

h—wall height; b - shelf width; s—channel thickness; R - radius

curvature; W - moment of resistance; I—moment of inertia; i - radius of inertia; Sx is the static half-section moment, x0 is the distance from the y-y axis to the outer surface of the wall; — the ratio of the calculated flange overhang to the channel thickness; - ratio of the design height to the thickness of the channel

3. The dimensions of the channels, cross-sectional area, reference values ​​for the axes and the mass of 1 m of the channel must correspond to:

for channels made of carbon boiling and semi-quiet steel - indicated in table. 1;

for channels made of carbon mild and low-alloy steel - indicated in table. 2.

Table 1

Errors

The seemingly simple shape of the channel is the result of an ideal calculation of the cross-sectional proportions. The document takes into account the parameters of the wall, flanges, channel thickness, resistance and inertia. Each standard size has its own indicators; it is impossible to calculate them proportionally. To do this, use tables of bent channel sizes.

All calculations of reference values ​​are given relative to nominal sizes. The value of steel density does not depend on the grade or additives - a fixed value of 7.85 g/cm3 is used.

Due to the nature of the production process, the state standard indicates errors for each of the parameters. If the product does not correspond to the table value, there is no need to suspect the manufacturer of deception - deviations from the nominal standards are taken into account and allowed.

By height

The range of bent channel according to GOST 8278-83 allows for height deviations. Allowed values:

• with a height of up to 50 mm - from 0.5 to 1;
• from 50 to 100 - 0.75 and 1.5;
• from 100 to 150 - 1.25 and 2 mm;
• above 150 - from one and a half to two and a half millimeters.

Minimum values ​​are given for products with high precision profiling, taking into account the difference in thickness (the limit is determined at 2.5 mm). The maximum error is allowed only with the lowest accuracy - normal.

Width

Using the same principle, possible discrepancies with the declared shelf width are calculated. However, for channels of the highest category, the requirements are more stringent - with a width of more than 100 mm, deviations are unacceptable. The indicator also affects the control angle of deviation - up to 100 mm, the range from 88.70 to 91.30 degrees is allowed, with a larger width the error is equal to one degree.

By lenght

The length of the bent channel section is also regulated. The minimum value is 3 meters, the upper limit is 11.8. It is indicated that, by agreement with the consumer, the length can be increased to 12 meters. In batches of measured length, no more than 7% of unmeasured lengths are allowed, otherwise it is considered defective. Standard deviations in cutting:

• +40 to 7 meters;
• over seven - additional +5 for each meter.

In the old edition of the technical requirements, the maximum deviation parameter was higher - +80 for any segments from 6 meters, without special conditions for a certain length.

The length according to the assortment of bent channel in GOST determines one of the criteria for rejection - twisting. The degree of twist along the longitudinal axis should not exceed the value in meters. The limit of acceptable result is 10 degrees for any standard size. Also, 0.1% of the total length of the segment is the permitted degree of curvature of the product.

Correct control of defects in accordance with technical standards is carried out at a certain distance from the end. For channels with high precision profiling - from 80 mm, 100 for high precision, 200 for regular.

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Bent channel is a product made by cold bending. This material has a cross-section resembling the letter “P” in shape. If we consider the visual distinctive points, it differs from hot-rolled by the presence of a rounded outer corner. To manufacture this type of channel, according to GOST 11474-76, rolled sheet blanks or strips are used. The price of a product largely depends on what steel it was made of.

The bent channel is manufactured according to established standards and requirements, which are regulated by GOST 11474-76. production is carried out on special roll forming machines using cold-rolled or hot-rolled steel. During manufacturing, such channels can be produced either equal-flanged or unequal-flanged. At the same time, the production of equal flanges is regulated by GOST 8278-83, and unequal flanges - 8281-80.

The channel number always corresponds strictly to its size, which is always indicated in mm. Let's consider an example: a channel 40x32x2.5 is available. What can be learned based on these parameters? So, 40 is the distance between the shelves, 32 is the width of the shelf, 2.5 is the wall thickness.

It is customary to distinguish between a bent equal-flange channel, which is manufactured in accordance with the established GOST 8278-83, and a bent non-equal-flange channel, which is manufactured in accordance with GOST 8281-80; it has its own specific purpose. Among some types of channels you can find models that have different shelf edges. Bent channel 160x80x5 and bent channel 120x50x3 are in great demand.

Steel channel is always valued in construction. It is highly durable and is often used as a load-bearing element. In most cases, the channel as a metal structure works primarily in bending. It is often used to construct a frame, as well as to erect partitions. When carrying out reconstruction work, a bent channel very often acts as an additional rib, which gives rigidity and stability to dilapidated buildings.

The equal-flange channel is installed on special roll forming mills. The material used is hot-rolled and cold-rolled steel, which is of average quality. In addition, carbon structural low-alloy steel is often used. The standard parameters are considered to be the following: the height of the product should be 50-400 mm, and the width of the shelves should be from 32 to 115 mm. If necessary, products can be manufactured not according to standards according to the individual order of the buyer. All standards and sizes are always indicated by GOST 8278-75.

Modern developed technologies make it possible to significantly expand the capabilities of the production process. Because of this, the variety of shapes produced is commonplace and hardly surprising. Due to the dynamically developing industry and human activity in general, the question arose about the manufacture of new types of channels.

Those products that are marked “U” are always manufactured with a slope. When the edges are parallel, the marking “P” is used; economical products with the edges parallel are marked “E”. If the planes are located parallel to each other, then the marking is “L”, special products are marked “C”. As for the maximum deviations, they should not exceed 4.5% of the total mass of the batch. The concept of mass deviation means the difference between the mass during delivery and the value that is calculated according to the developed tables.

The channel shape has the following symbols:

U - the internal edges are sloped

P – parallel faces

E - economical with parallel edges

L – parallel edges of the light series

With special

As mentioned earlier, the maximum batch deviations should not exceed 4.5% and 6% for an individual product. The definition of weight deviation hides the concept of the difference between the actual weight during the delivery period and that calculated according to a special table.

The length of the bent equal-flange channel can be of several types:

- measured length

- measured length in combination with unmeasured length, but in an amount of no more than 5% of the total mass of the batch

- unmeasured length

- limited length within unmeasured limits.

Main types of channel:

The special channel is used primarily in the automotive industry. It is manufactured according to GOST 19425-74. To use the product in carriage building during production, they are guided by GOST 5267-90. Its standard length ranges from 4 to 13 meters. If necessary, it can be made in a larger size. These types of channels are always made using rolled steel on special pipe machines. In this case, the steel is of ordinary quality. Typically, the height of the product ranges from 50 to 400 mm, and the width ranges from 32 to 115 mm.

All steel bent unequal-flange channels are manufactured using roll forming machines, and the steel must be cold-rolled or hot-rolled. All requirements and requirements are regulated by GOST 8281-80. All channels are usually divided into numbers. They, in turn, indicate the distance between the shelves, which is always expressed in mm. Depending on the rolling precision used, bent channels are divided into:

— high accuracy with marking “A”

— increased accuracy with marking “B”

- normal accuracy marked “B”.

The highest category of bent unequal and equal flange channels is produced under the markings A and B.

Forms of bent channel:

Channel with parallel flange edges GOST 8240-97.

The characteristics and range of steel channels are established by the following standards:

· Hot rolled channel (GOST 8240-89);

· Bent equal flange channel (GOST 8278-75);

· Bent unequal flange channel (GOST 8281-80)

· Special channel (19425-74).

Any hot-rolled channel is always divided into a channel with a slope of the internal edges of the flanges and with a parallel arrangement of the edges of the flanges.

Channels belong to the category of long products. Manufactured according to technical specifications:

· GOST 535-88 – hot-rolled steel;

· GOST 11474-76 – bent steel;

· GOST 8278-83 – equal-flange bent steel;

· GOST 8281-80 – unequal bent steel;

· GOST 8240 – hot-rolled carbon and low-alloy steel;

· GOST 5267 – special for carriage building;

· GOST 5420 – special for tractors;

· GOST 19425-74 – special steel.

Channel GOST 8240-89 is divided into:

· channel with a slope of the internal edges of the shelves: No. 5, 6.5, 8, 10, 12, 14, 16, 16a, 18, 18a, 20, 22, 24, 27, 30, 33, 36, 40;

· channel with parallel edges of shelves P: No. 5P, 6.5P, 8P, 10P, 12P, 14P, 16P, 16aP, 18P, 18aP, 20P, 22P, 24P, 27P, 30P, 33P, 36P, 40P.

According to rolling accuracy, channel GOST 8240, GOST 19425, GOST 8278, GOST 8281 are manufactured:

· increased accuracy – B;

· ordinary accuracy – V.

An example of a channel designation: hot-rolled steel channel No. 10, steel grade St3, length 10 m GOST 8240-89 – channel No. 10 St3 GOST 8240-89.

The Taurus is a steel beam that is shaped like the letter “T”. Structural steel is used for its manufacture. Typically, the brand acts as a necessary element for load-bearing structures. Structural steel is used to make the beam. This product is an ideal solution for those who want to glaze balconies with high quality, as well as for installing glass garden greenhouses.

Rice. 1. Bent channel according to GOST 8278-83

Legend:

h – channel height;

S – flange thickness;

b – shelf width;

R – radius of internal curvature.

Dimensions and weight of bent channels made of carbon boiling and semi-quiet steel

Dimensions and weight of bent channels made of carbon boiling and semi-quiet steel

Note: The weight of 1 m of profile is calculated based on the nominal dimensions at a material density of 7850 kg/m3 and is a reference value.

Dimensions and weight of bent channels made of carbon mild and low-alloy steel

Continued Dimensions and weight of bent channels made of carbon mild and low-alloy steel

Note: The weight of 1 m of profile is calculated based on the nominal dimensions at a material density of 7850 kg/m3 and is a reference value.

About steel grades

The price of a bent channel per meter often depends on the grade of steel used as a raw material in production. The document does not specify uniform requirements for the type of steel; instead, a reference is made to GOST 11474-76. It regulates raw material standards for steel profiles, listing acceptable grades.

The most common type is St3sp - structural carbon steel of ordinary quality. The document is consulted if doubts arise when deciphering the brand - sometimes this can reveal unscrupulous suppliers of low-quality metal products.

Price

Due to the high assortment, manufacturers rarely indicate the price per linear meter - more often only the minimum value is given. For calculations for each standard size, there are calculators on websites selling metal products.

There are no special requirements for packaging and transportation of profiled steel products. Delivery details and the choice of storage method are discussed separately by the manufacturer and consumer of the product.

A bent channel according to GOST assortment is available in the Metallbaza catalog. For convenience, all varieties available are listed on the page. For each type the following are indicated:

• price of bent channel per meter;
• shelf width;
• product wall thickness;
• height.

There are several grades of steel to choose from. All products and standard sizes comply with the assortment in GOST for bent channels and meet the quality standards of raw materials.