The parameters of one of the most popular types of metal - steel corner equal-shelf - determined by GOST 8509-93. The use of the Guest in the production of such products not only unifies its types, but also improves the interaction of producers and consumers. Dimensions and weight of equal-shelf steel corners, which are made in full compliance with the regulatory document, allowing you to use these characteristics to accurately calculate material costs, which is very important when carrying out construction and repair work.
Photo of a steel corner of the same shelf
Varieties of steel corners of equal shelf type
The square angle is divided into several categories depending on the method of manufacture and used for its production. All geometric parameters, as well as permissible deviations from it are regulated by two regulations:
- GUEST 8509-93 (production of hot-rolled corners of equal-shelf type);
- Guest 19771-93 (production of equal-shelf steel corners, obtained by bending).
It is possible to get acquainted with requirements of GOST and assortment of steel hot-rolled and bent ravnopolochny corners, by downloading the relevant documents in pdf format at the links below.
GUEST 8509-93 Corners steel hot-rolled equal-shelf. Assortment
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GUEST 19771-93 Corners steel bent equal-shelf. Assortment
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The difference between ravnopolochnyh and neravnopolochnyh products is, that the first regiments have the same dimensions (width), and in others - different. Hot-rolled corner profiles are made by the following technology: the hot workpiece is rolled between the shafts of a special rolling mill, Where is she, under pressure, a product with the required geometric shape and dimensions is formed.
To make a metal angle of bent type, sheet metal of the appropriate size is bent on the equipment of profile-bending type or on pipe mills. Hot-rolled profiles due to the peculiarities of their production have a higher strength, but different corners have their advantages: high dimensional accuracy, light weight, wide range.
The isosceles angle is a popular material as in industrial construction, and in the private sector
In the range of equal-shelf corners there are products from:
- high strength steel;
- alloyed, high-alloy steel;
- alloys, characterized by high heat resistance, heat resistance and corrosion resistance.
The most common material for the production of bent corner is also carbon steel, the characteristics of which must meet GOST 380-94.
Main characteristics
From the table of assortment of steel corners of equal-shelf type it is possible to learn their various parameters: the mass of one running meter; the cross-sectional area of the profile and other dimensions. To calculate the mass of hot-rolled or bent profile, the density of the material, of which it is made, accepted for 7850 kg / m3.
The mass of a running meter of an equilateral angle
Radius of rounding of a profile of equal-shelf steel corners, are given in the table with the assortment, are not controlled parameters, but they are needed to calibrate the products. The following designations of sizes and other parameters are accepted in the assortment table, which characterizes the steel corner:
- t is the wall thickness of the shelves;
- X0, Y0 - the distance from the outer edges of the shelves of the corner to the center of gravity;
- R is the radius of curvature;
- b is the width of the shelf;
- r is the radius of curvature of the faces of the shelves;
- I - moment of inertia;
- i is the radius of inertia;
- F is the cross-sectional area of the profile;
- Ixy - moment of inertia, which develops centrifugal forces.
Designation of the basic geometrical parameters of a hot-rolled corner. Below is a table of the range of this type of metal
Table 1: Assortment of hot-rolled corners
Steel isosceles angles can be of normal accuracy (marked with the letter "B") and increased (the letter "A" is present in the label). The following deviations of width of shelves are allowed by GOST:
- for products № 2-4,5 - ± 1 mm;
- № 5-9 - ± 1.5 mm;
- № 10-15 - ± 2 mm;
- № 16-20 - ± 3 mm;
- № 22-25 - ± 4 mm.
Corner shelves must be perpendicular to each other within the tolerances according to the table
The thickness of the shelf of the equal-shelf steel corner in accordance with GOST may have the following deviations, which are measured in millimeters (div. table).
The customer of party of equal-shelf steel corners can agree with the producer of production about that, that instead of the permissible deviations in wall thickness will be used tolerance for deviations in product weight, which can be for profiles:
- № 2-7,5: from -5 to +3% (classes "A" and "B");
- with № over 7,5: ±2,5% (class "A"), from - 5 to +3% (class "B").
Deviations in the size of the corner depending on the class
In accordance with the provisions of DST, steel corners, belonging to the category of isosceles, can be released to the customer in length 3-12 m. By prior agreement of the customer with the manufacturer, these products can be released in length, exceeding 12 meters. So, GOST stipulates the possibility of vacation ravnopolochnyh steel corners of the following sizes in the longitudinal direction:
- measured length;
- measured value with the inclusion in the batch of products of unmeasured length (the number of such corners should not exceed 5% of the total);
- length, which is a multiple of the dimensional;
- length, multiple dimensional, when the content of the corners of immeasurable length (their number should not exceed 5% of the total);
- of immeasurable length;
- length, is in immeasurable interval.
Cognitive video of Soviet times, highlights in detail the nuances of the production of high-grade metal.
For the length of dimensional steel corners and products, whose length is a multiple of the dimensional, GOST sets the following tolerances:
- not more 4 meters - 30 mm;
- from 4 to 6 meters - 50 mm;
- over 6 meters - 70 mm;
- from 4 to 7 meters (at the request of the customer) – 40 mm;
- over 7 meters (by prior agreement with the customer) – 5 mm for each additional meter of product.
Parameters according to GOST 19771-93
According to Gost 19771-93, steel corner profiles are made of three categories of accuracy:
- "B" - ordinary;
- "B" - increased;
- "A" - high.
The process of forming the profile of the bent steel corner
In the table, in which the whole range of bent isosceles corners is presented, the main parameters of such products are indicated: mass 1 running meter, cross-sectional area, etc.. The assortment tables provide data for steel corners of two categories:
- made of ordinary carbon steel, semi-calm and boiling, as well as alloys, in which the resistance to rupture corresponds to 460 N / mm2;
- made of ordinary calm and semi-calm carbon steel and alloys, resistance to rupture in which exceeds 460 N / mm2.
In the tables, in which parameters of equal-shelf steel corners of the given categories are resulted, the following designations are accepted:
- S is the thickness of the shelf;
- Y0, X0 - the distance between the outer faces of the corner and its center of gravity;
- R is the radius of curvature of the profile;
- b is the width of the shelf;
- I - moment of inertia;
- i is the radius of inertia of the profile;
- F is the cross-sectional area of the profile;
- n = b-S-R / S - the ratio of the calculated value of the shelf overhang to its thickness.
Designation of the basic geometrical parameters of a bent corner. Below is a table of the assortment of this type of rental
Table 2: Parameters of corners from boiling and semi-quiet steel
Table 3: Parameters and reference values for calm steel corners
The values of the cross-sectional area of the steel profile of the isosceles corner are given in the tables, as well as the weight of one meter of the product is calculated taking into account the nominal tabular dimensions (permissible deviations are not taken into account in the calculations, which in the production of metal products are inevitable). The mass of one running meter is calculated taking into account that, that the density of the metal, from which the corner is made, is equal to 7850 kg / m3.
The width of the shelves of steel corners, depending on, which exactly matches their profiling, may have the following deviations:
- high accuracy (to the number 2,5): ± 0.75 - ± 1.5 mm;
- high accuracy (corresponding numbering above 2,5): ± 1 - ± 1.75 mm;
- high accuracy: ± 1.25 - ± 2.5 mm;
- ordinary accuracy class: ± 1.5 - ± 3 mm
Steel isosceles angles, issued in accordance with the specified Guest, can be released to the customer of the next length (in the interval 3-12 m):
- dimensional;
- immeasurable;
- length, which is a multiple of the dimensional;
- dimensional, at the same time in party there are products of immeasurable length, the number of which does not exceed 7% of the total;
- multiple dimensional, at the same time in party there are corners of immeasurable length, but their number is not more 7% of the total.
Possessing a democratic price, hot-rolled and bent corner from usual carbon steel differs in good resistance to loadings of various type. These characteristics allow you to successfully use these products in many areas. Steel corners of this type are used to create frame metal structures for various purposes, and also with their help carry out reinforcement of concrete designs.
When choosing an equal-shelf steel corner should be borne in mind, that it has low corrosion resistance. Therefore, in those cases, when the resistance of the created metal structure to corrosion is important, it is recommended to replace such corner with galvanized or aluminum products, which will last much longer.