Sectional area of ​​the corner. Hot rolled equal flange steel angles. Tolerances and deviations of the main characteristics of the angle

2 According to rolling precision, angles are made:

A-high precision;
B-usual accuracy.

3 Maximum deviations in the dimensions of the corners should not exceed those indicated in Table 2.

table 2 Corner number Limit deviations along the shelf width by shelf thickness up to 6 incl. from 6.5 to 9 inclusive. over 9 A IN A IN A IN From 2 to 4.5 + 1,0 + 0,2 + 0,3 - - - - -0,3 -0,4 From 5 to 9 + 1,5 + 0,2 + 0,3 + 0,2 + 0,3 + 0,3 + 0,4 -0,4 -0,5 -0,5 -0,6 -0,5 -0,6 From 10 to 15 + 2,0 - - + 0,3 + 0,4 + 0,3 + 0,4 -0,5 -0,6 -0,6 -0,7 From 16 to 20 + 3,0 - - - - + 0,4 + 0,5 -0,7 -0,8 From 22 to 25 + 4,0 - - - - + 0,4 + 0,5 -0,8 -0,9

4 By agreement between the manufacturer and the consumer, it is allowed to manufacture angles with offset maximum deviations in the thickness of the shelf within the permissible deviations of the corresponding accuracy. 5 By agreement with the consumer, deviations in shelf thickness may be replaced by maximum deviations in weight in accordance with Table 3. 6 Deviation from right angle should not exceed 35". By agreement between the manufacturer and the consumer, the deviation from the right angle at the apex should not exceed: 1.0 mm - for corners with a shelf width up to 50 mm inclusive; 2.0 mm - for corners with a shelf width over 50 to 100 mm inclusive; 3.0 mm - for corners with a shelf width over 100 to 200 mm.

7 The blunting of external angles (including the apex angle) is not controlled.
At the request of the consumer, the blunting of external corners (including the apex angle) should not exceed:

0.3 shelf thickness - for corners up to 10 mm thick inclusive;
3.0 mm - for corners with a thickness over 10 to 16 mm inclusive;
5.0 mm - for corners with a thickness of over 16 mm.

8 Corners are made from 4 to 12 m long:

Measured length;
measured length with unmeasured length in an amount of no more than 5% of the mass of the batch;
multiple measured length,
multiple measured lengths with non-measured ones in an amount of no more than 5% of the mass of the batch;
unmeasured length;
limited length within unmeasured.

8.1 By agreement between the manufacturer and the consumer, angles are manufactured in measured and multiple measured lengths with unmeasured lengths of more than 5% of the batch weight.

8.2 It is allowed to manufacture corners with a length of at least 3 m and over 12 m.

9 Maximum deviations along the length of the corners of the measured length or a multiple of the measured length must not exceed:

30 mm - for lengths up to 4 m inclusive;
+ 50 mm - for lengths over 4 to 6 m inclusive;
+ 70 mm - for lengths over 6 m.

At the request of the consumer, for corners with a length of over 4 to 7 m, the maximum length deviations should not exceed + 40 mm, more than 7 m - + 5 mm for each additional meter.

10 The curvature of the corners should not exceed 0.4% of the length.
At the consumer's request, corners are manufactured whose curvature does not exceed 0.2% of the length. For angles from No. 2 to 4.5 inclusive, the curvature is checked at a length of 1 m.

11 The cross-sectional dimensions of the corners and the bluntness of the corners are measured at a distance of at least 500 mm from the end of the rod.

APPENDIX A (recommended)

PART 1. EQUAL ANGLES. DIMENSIONS
(ISO 657-1-89) 1 Distribution area
This part of ISO 657 covers the dimensions of hot-rolled equal-flange angles.

2 This standard contains the terms of this part of ISO 657. At the time of publication, this edition was current.
All standards are subject to revision, so the most recent edition of the standards must be used.
Member countries of the IEC and ISO must be provided with valid international standards.
ISO 657-5-76. Hot-rolled steel profiles, part 5. Equal and unequal angles, maximum deviations in metric and inch series.

3 Dimensions

3.1 Preferred sizes are in bold.

3.2 The radii of internal curvature are given for information and are shown in Table A.1.

3.3 The radius of curvature of the shelves is not defined, but can be calculated if necessary.

Table A.1
Size	Weight kg/m	S, cm 2	Quantities			Distance from center of gravity			Reference values ​​for axes
									x-x = y-y			u - u		v - v
			A, mm	t, mm	r root, mm	C x = C y cm	WITHu, cm	WITHv, cm	I x = I y, cm 4	r x = r y, cm	Z x = Z y, cm 3	I u, cm 4	r u, cm	Iv, cm 4	r v, cm	Zv, cm 3
20x20x3	0,88	1,12	20	3	3,5	0,598	1,41	0,846	0,392	0,590	0,279	0,618	0,742	0,165	0,383	0,195
25x25x3	1,12	1,42	25	3	3,5	0,723	1,77	1,02	0,803	0,751	0,452	1,27	0,945	0,334	0,484	0,326
25x25x4	1,45	1,85	25	4	3,5	0,762	1,77	1,08	1,02	0,741	0,586	1,61	0,931	0,430	0,482	0,399
30x30x3	1,36	1,74	30	3	5	0,835	2,12	1,18	1,40	0,899	0,649	2,22	1,13	0,585	0,581	0,496
30x30x4	1,78	2,27	30	4	5	0,878	2,12	1,24	1,80	0,892	0,850	2,85	1,12	0,757	0,577	0,607
35x35x4	2,09	2,67	35	4	5	1,00	2,47	1,42	2,95	1,05	1,18	4,68	1,32	1,23	0,678	0,865
35x35x5	2,57	3,28	35	5	5	1,04	2,47	1,48	3,56	1,04	1,45	5,64	1,31	1,49	0,675	1,01
40x40x3	1,84	2,35	40	3	6	1,07	2,83	1,52	3,45	1,21	1,18	5,45	1,52	1,44	0,783	0,949
40x40x4	2,42	3,08	40	4	6	1,12	2,83	1,58	4,47	1,21	1,55	7,09	1,52	1,86	0,777	1,17
40x40x5	2,97	3,79	40	5	6	1,16	2,83	1,64	5,43	1,20	1,91	8,60	1,51	2,26	0,773	1,38
45x45x4	2,74	3,49	45	4	7	1,23	3,18	1,75	6,43	1,36	1,97	10,2	1,71	2,68	0,876	1,53
45x45x5	3,38	4,30	45	5	7	1,28	3,18	1,81	7,84	1,35	2,43	12,4	1,70	3,26	0,871	1,80
50x50x4	3,06	3,89	50	4	7	1,36	3,54	1,92	8,97	1,52	2,46	14,2	1,91	3,73	0,979	1,94
50x50x5	3,77	4,80	50	5	7	1,40	3,54	1,99	11,0	1,51	3,05	17,4	1,90	4,55	0,973	2,29
50x50x6	4,47	5,69	50	6	7	1,45	3,54	2,04	12,8	1,50	3,61	20,3	1,89	5,34	0,968	2,61
60x60x5	4,57	5,82	60	5	8	1,64	4,24	2,32	19,4	1,82	4,45	30,7	2,30	8,03	1,17	3,46
60x60x6	5,42	6,91	60	6	8	1,69	4,24	2,39	22,8	1,82	5,29	36,1	2,29	9,44	1,17	3,96
60x60x8	7,09	9,03	60	8	8	1,77	4,24	2,50	29,2	1,80	6,89	46,1	2,26	12,2	1,16	4,86
65x65x6	5,91	7,53	65	6	9	1,80	4,60	2,55	29,2	1,97	6,21	46,3	2,48	12,1	1,27	4,74
65x65x8	7,73	9,85	65	8	9	1,89	4,60	2,67	37,5	1,95	8,13	59,4	2,46	15,6	1,26	5,84
70x70x6	6,38	8,13	70	6	9	1,93	4,95	2,73	36,9	2,13	7,27	58,5	2,68	15,3	1,37	5,60
70x70x7	7,38	9,40	70	7	9	1,97	4,95	2,79	42,3	2,12	8,41	67,1	2,67	17,5	1,36	6,28
75x75x6	6,85	8,73	75	6	9	2,05	5,30	2,90	45,8	2,29	8,41	72,7	2,89	18,9	1,47	6,53
75x75x8	8,99	11,4	75	8	9	2,14	5,30	3,02	59,1	2,27	11,0	93,8	2,86	24,5	1,46	8,09
80x80x6	7,34	9,35	80	6	10	2,17	5,66	3,07	55,8	2,44	9,57	88,5	3,08	23,1	1,57	7,55
80x80x8	9,63	12,3	80	8	10	2,26	5,66	3,19	72,2	2,43	12,6	115	3,06	29,9	1,56	9,37
80x80x10	11,9	15,1	80	10	10	2,34	5,66	3,30	87,5	2,41	15,4	139	3,03	36,4	1,55	11,0
90x90x7	9,61	12,2	90	7	11	2,45	6,36	3,47	92,5	2,75	14,1	147	3,46	38,3	1,77	11,0
90x90x8	10,9	13,9	90	8	11	2,50	6,36	3,53	104	2,74	16,1	166	3,45	43,1	1,76	12,2
90x90x9	12,2	15,5	90	9	11	2,54	6,36	3,59	116	2,73	17,9	184	3,44	47,9	1,76	13,3
90x90x10	15,0	17,1	90	10	11	2,58	6,36	3,65	127	2,72	19,8	201	3,42	52,6	1,75	14,4
100x100x8	12,2	15,5	100	8	12	2,74	7,07	3,87	145	3,06	19,9	230	3,85	59,9	1,96	15,5
100x100x10	15,0	19,2	100	10	12	2,82	7,07	3,99	177	3,04	24,6	280	3,83	73,0	1,95	18,3
100x100x12	17,8	22,7	100	12	12	2,90	7,07	4,11	207	3,02	29,1	328	3,80	85,7	1,94	20,9
120x120x8	14,7	18,7	120	8	13	3,23	8,49	4,56	255	3,69	29,1	405	4,65	105	2,37	23,1
120x120x10	18,2	23,2	120	10	13	3,31	8,49	4,69	313	3,67	36,0	497	4,63	129	2,36	27,5
120x120x12	21,6	27,5	120	12	13	3,40	8,49	4,80	368	3,65	42,7	584	4,60	152	2,35	31,6
125x125x8	15,3	19,5	125	8	13	3,35	8,84	4,74	290	3,85	31,7	461	4,85	120	2,47	25,3
125x125x10	19,0	24,2	125	10	13	3,44	8,84	4,86	356	3,84	39,3	565	4,83	146	2,46	2,46
125x125x12	22,6	28,7	125	12	13	3,52	8,84	4,98	418	3,81	46,6	664	4,81	172	2,45	34,6
150x150x10	23,0	29,3	150	10	16	4,03	10,6	5,71	624	4,62	56,9	990	5,82	258	2,97	45,1
150x150x12	27,3	34,8	150	12	16	4,12	10,6	5,83	737	4,60	67,7	1170	5,80	303	2,95	52,0
150x150x15	33,8	43,0	150	15	16	4,25	10,6	6,01	898	4,57	83,5	1430	5,76	370	2,93	61,6
180x180x15	40,9	52,1	180	15	18	4,98	12,7	7,05	1590	5,52	122	2520	6,96	653	3,54	92,7
180x180x18	48,6	61,9	180	18	18	5,10	12,7	7,22	1870	5,49	145	2960	6,92	768	3,52	106
200x200x16	48,5	61,8	200	16	18	5,52	14,1	7,81	2340	6,16	162	3720	7,76	960	3,94	123
200x200x20	59,9	76,3	200	20	18	5,68	14,1	8,04	2850	6,11	199	4530	7,70	1170	3,92	146
200x200x24	71,1	90,6	200	24	18	5,84	14,1	8,26	3330	6,06	235	5280	7,64	1380	3,90	167
250x250x28	104	133	250	28	18	7,24	17,7	10,2	7700	7,62	433	1220	9,61	3170	4,89	309
250x250x35	128	163	250	35	18	7,50	17,7	10,6	9260	7,54	529	1470	9,48	3860	4,87	364

Notes
1 ISO member countries may include their required corner sizes in their national standards.
From the assortment for equal angles given in the table, the national standard can include those sizes of angles that S- cross-sectional area, cm 2;
t-thickness, mm;
r root - radius of internal curvature, mm;
r toc - radius of curvature of shelves, mm;
A- shelf width, mm.

3 When calculating the mass of 1 m, the density of steel was taken to be 7.85 kg/dm 3.

APPENDIX B (recommended)
HOT-ROLLED STEEL PROFILES
PART 5. EQUAL AND UNEQUAL ANGLES IN METRIC AND INCH SERIES. TOLERANCES (ISO 657-5-76)
1 Subject of the standard and scope
This international standard regulates the maximum deviations in dimensions of hot-rolled steel equal and unequal angles in the metric and inch series. The dimensions of the angles in the metric series must comply with ISO 657-1 and ISO 657-2, in the inch series - ISO 657-3 and ISO 657-4.

2 Maximum deviations for shelf width
The maximum deviations for the width of the shelf must correspond to those given in Table B.1.

Table B.1 | Maximum deviations in width
Metric series, mm			Inch series, inch
Shelf width 1		Limit	Shelf width 1		Limit
Over	From start to finish	deviations	Over	From start to finish	deviations
-	50	+ 1,0	-	2	+ 0,04
50	100	+ 1,5	2	4	+ 0,06
100	150	+ 2,0	4	6	+ 0,08
150	200	+ 3,0	6	8	+ 0,12

3 Limit deviations for flange thickness
Maximum deviations in thickness of equal and unequal angles must correspond to those given in Table B.2

Table B.2 | Maximum deviations in thickness
Metric series, mm			Inch series, inch
Shelf width 1		Limit	Shelf width 1		Limit
Over	From start to finish	deviations	Over	From start to finish	deviations
-	50	+ 0,5	-	2	+ 0,02
50	100	+ 0,8	2	4	+ 0,03
100	150	+ 1,0	4	6	+ 0,04
150	200	+ 1,2	6	8	+ 0,05

1 For unequal corners, the width of the larger shelf is taken as the base.
Note -
For angles with a flange length over 75 mm, the maximum deviations in mass are + 2.5% per unit length and can be replaced by maximum deviations in thickness. The mass per unit length of the angle is given in the appendix A.

4 Limit deviations when cutting to lengths
Maximum length deviations when cutting equal and unequal angles into normal and exact lengths must correspond to those given in Tables B.3 and B.4, respectively.

5 Curvature

5.1. The maximum permissible curvature for equal and unequal angles must correspond to that given in Table B.5.

1 For unequal corners, the width of the larger shelf is taken as the base.

Table B.6 | Deviation from right angle
Metric series			Inch series
Shelf width		Deviation	Shelf width 1		Deviation
Over	From start to finish		Over	From start to finish
-	50	1,0	-	2	0,04
50	100	2,0	2	4	0,08
100	200	3,0	4	8	0,12

1 For unequal corners, the width of the larger shelf is taken as the base.

The parameters of one of the most popular types of rolled metal - steel equal-flange angle - are determined by GOST 8509-93. The use of GOST in the production of such products not only unifies their types, but also improves the interaction between producers and consumers. The dimensions and weight of equal-flange steel angles, which are manufactured in full compliance with the regulatory document, make it possible to use these characteristics to accurately calculate material consumption, which is very important when carrying out construction and repair work.

Varieties of equal-flange steel angles

Equal angle corners are divided into several categories depending on the manufacturing method and the raw materials used for their production. All geometric parameters, as well as permissible deviations for them, are regulated by two regulatory documents:

1. GOST 8509-93 (production of hot-rolled equal-flange angles);
2. GOST 19771-93 (production of equal-flange steel angles obtained by bending).

You can familiarize yourself with the GOST requirements and the range of hot-rolled and bent equal-flange steel angles by downloading the relevant documents in pdf format from the links below.

The difference between equal-shelf and unequal-shelf products is that the former have shelves of the same dimensions (width), while the latter have different shelves. Hot-rolled corner profiles are manufactured using the following technology: a hot billet is rolled between special rollers, where, under pressure, it is formed into a product with the required geometric shape and dimensions.

In order to produce a metal corner of the bent type, rolled sheets of the appropriate size are bent on roll forming equipment or on pipe mills. Due to the peculiarities of their production, hot-rolled profiles are characterized by higher strength, but bent corners also have their advantages: high dimensional accuracy, light weight, wide range.

The range of equal angle angles includes products from:

• high strength steel;
• alloyed, high-alloy steel;
• alloys characterized by increased heat resistance, heat resistance and corrosion resistance.

The most common material for the production of bent angles is also carbon steel, the characteristics of which must comply with GOST 380-94.

Main characteristics

Using the assortment table for equal-flange steel angles, you can find out their various parameters: weight of one linear meter; profile cross-sectional area and other dimensions. To calculate the mass of a hot-rolled or bent profile, the density of the material from which it is made is taken as 7850 kg/m3.

The radii of curvature of the profile of equal-flange steel angles, given in the table with the assortment, are not controlled parameters, but they are necessary for calibrating products. In the assortment table, the following designations of sizes and other parameters that characterize steel angles are used:

• t – shelf wall thickness;
• X0, Y0 – distances from the outer edges of the corner flanges to its center of gravity;
• R – radius of curvature;
• b – shelf width;
• r – radius of curvature of the edges of the shelves;
• I – moment of inertia;
• i – radius of gyration;
• F – profile cross-sectional area;
• Ixy is the moment of inertia that is developed by centrifugal forces.

Designations of the main geometric parameters of hot-rolled angles. Below is a table of the assortment of this type of rolled metal

Equal-flange steel angles can be of normal precision (marked with the letter “B”) and high-precision (marked with the letter “A”). GOST allows the following deviations in the width of shelves:

• for products No. 2–4.5 – ±1 mm;
• No. 5–9 – ±1.5 mm;
• No. 10–15 – ±2 mm;
• No. 16–20 – ±3 mm;
• No. 22–25 – ±4 mm.

The thickness of the flange of an equal-flange steel angle in accordance with GOST may have the following deviations, measured in millimeters (see table).

The customer of a batch of equal-flange steel angles can agree with the product manufacturer that instead of permissible deviations in wall thickness, a tolerance for deviations in the mass of the product will be used, which can be for profiles:

• No. 2–7.5: from –5 to +3% (classes “A” and “B”);
• with No. over 7.5: ±2.5% (class “A”), from – 5 to +3% (class “B”).

According to the provisions of GOST, steel angles belonging to the category of equal flanges can be supplied to the customer with a length of 3–12 m. By prior agreement between the customer and the manufacturer, these products can be supplied with a length exceeding 12 meters. Thus, GOST stipulates the possibility of tempering equal-flange steel angles of the following sizes in the longitudinal direction:

• measured length;
• measured size with the inclusion of products of unmeasured length in the batch (the number of such corners should not exceed 5% of the total volume);
• length, which is a multiple of the measured length;
• a length that is a multiple of the measured length, when the batch contains angles of unmeasured length (their number should not exceed 5% of the total volume);
• unmeasured length;
• length, located in an unmeasured interval.

An educational video from Soviet times, covering in detail the nuances of the production of long rolled metal products.

For the length of measured steel angles and products whose length is a multiple of the measured length, GOST establishes the following permissible deviations:

• no more than 4 meters – 30 mm;
• from 4 to 6 meters – 50 mm;
• over 6 meters – 70 mm;
• from 4 to 7 meters (at customer’s request) – 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

In accordance with GOST 19771-93, steel corner profiles are manufactured in three accuracy categories:

• “B” – ordinary;
• “B” – increased;
• "A" - high.

The table, which presents the entire assortment of bent equal-flange angles, indicates the main parameters of such products: weight of 1 linear meter, cross-sectional area, etc. The assortment tables provide data for steel angles of two categories:

• made from ordinary carbon steel, semi-quiet and boiling, as well as alloys whose tensile strength corresponds to values ​​up to 460 N/mm 2;
• made from ordinary mild and semi-mild carbon steel and alloys, the tensile strength of which exceeds 460 N/mm 2.

In the tables that show the parameters of equal-flange steel angles of these categories, the following designations are used:

• S – flange thickness;
• Y0, X0 – distances between the outer edges of the angle and its center of gravity;
• R – radius of curvature of the profile;
• b – shelf width;
• I – moment of inertia;
• i – radius of gyration of the profile;
• F – profile cross-sectional area;
• n=b-S-R/S – the ratio of the calculated value of the shelf overhang to its thickness.

Designations of the main geometric parameters of a bent angle. Below is a table of the assortment of this type of rolled product

Table 2: Parameters of angles made of boiling and semi-quiet steel

Table 3: Parameters and reference values ​​for mild steel angles

The values ​​of the cross-sectional area of ​​the steel equal-flange angle profile given in the tables, as well as the weight of one meter of the product, are calculated taking into account the nominal table dimensions (the calculations do not take into account permissible deviations, which are inevitable in the production of metal products). The weight of one linear meter is calculated taking into account the fact that the density of the metal from which the corner is made is 7850 kg/m 3 .

A fairly common rolled metal product can be called equal angle angles. When manufacturing them, the standards established in GOST are applied. Due to this, the products are presented in standardized types. When considering the range of equal-flange angles, one should take into account the fact that weight and dimensions are important for making accurate calculations when developing design or technical documentation. The distribution of the material can be associated with its exceptional performance qualities, which we will discuss in more detail later.

Main characteristics

In technical documentation you can find a variety of information that can be used in calculations. The table used allows you to determine the following characteristics:

1. Weight of one linear meter. The weight of the equal-flange angle is taken into account when calculating what load will be exerted on the structure being created. The weight of a steel angle largely depends on the size and type of material used in manufacturing. The density of the metal used can vary over a fairly wide range.
2. Basic dimensions. The corner can have very different sizes. They are taken into account in calculations. The dimensions of the metal corner can vary over a fairly wide range, as they are used to create various structures.
3. The profile of a metal equal-flange material can have a very different cross-sectional area. This parameter also indicates how much load will be applied.
4. The drawing and other technical information also contains information about the radius of curvature of the profile. This indicator is not a controlled parameter, but is used to calibrate the product. The range of hot-rolled equal flange steel angles can be represented by a material that has even or different flanges. Uneven-flanged versions have also become widespread.
5. The table indicates the wall thickness of the shelves. As the thickness increases, the moment of resistance increases and the product becomes able to withstand greater loads. However, due to the use of more metal, the weight of the product increases significantly.

An equal angle angle can be classified according to its accuracy. Let's take the following product groups as an example:

1. Normal accuracy, marked with the letter "B".
2. Increased accuracy, marking is represented by the letter “A”.

The shelf thickness indicator may have a deviation in accordance with the tabular data.
The regulatory documentation also indicates what length of workpieces can be sent to the customer. As an example, the length indicator should be 3-12 m. By prior agreement, material of greater length can be supplied.

Types of equal angles

Equal-flange versions have become very widespread today. They are produced in various options execution. Considering the types of metal corners, we note that the geometric dimensions and classification of products are regulated by two main regulatory documents:

1. A hot-rolled equal flange angle is obtained by using technology that involves the impact high temperature. GOST 8509-93 is used as regulatory documentation. Due to the use of special production technology, the resulting product has very high performance qualities. However, the production process is associated with a fairly large number of technological difficulties.
2. Bent steel angles are also widely used. To standardize the main parameters in this case, GOST 19771-93 is used. Due to the use of cold bending technology, the production process is significantly accelerated.

Download GOST 19771-93. Equal-flange bent steel corners. Assortment."

A distinctive feature of equal-angle corners is that their shelves have the same geometric dimensions. Hot rolled products are produced by passing a hot billet through rollers. When pressure is applied to the softened alloy, a geometric shape and certain dimensions are formed.
When cold bending, special equipment is used that can exert a significant mechanical effect. It is worth considering that in this case, only rolled sheets with a relatively small cross-sectional thickness can be used as a workpiece.

The most common metal used in the production of equal-flange angles is carbon steel. This is due to its high strength and relatively low cost, ease of production.

Corner sizes

The issue of dimensions was touched upon earlier when considering the main indicators that characterize a steel angle. The following points should also be noted:

1. The weight of the product is indicated. Metal corners are used in the manufacture of critical products. That is why the weight of the material itself is also taken into account in the calculations.
2. The main dimensions of the equal-flange angle are also indicated for the development of design documentation and selection of the most suitable product.
3. Equal-flange steel angles are also characterized by profile cross-sectional area, flange width, radius of curvature, and wall thickness. All these indicators are maintained as standards and are not indicated by manufacturers; if necessary, they can be found in reference documentation.

An equilateral corner can have a variety of sizes. A wide range allows you to select the most suitable material for use in a particular case.

Application of steel angle

Metals are found almost everywhere today. Combining lightness and high strength, the material has become almost irreplaceable and is used in the construction of various structures and mechanisms. Steel angles can be made using various metals. Due to their special geometry, they can absorb greater loads than, for example, sheet material. Rolled corner or bent steel angle is used:

1. During the construction of load-bearing structures. In order for the structure to take a large load, the product in question can be used as the main material. An example is the construction of warehouses, when lightweight materials are used as cladding. sheet metal, which covers a stable frame. Due to this, costs are significantly reduced and the strength of the structure is increased.
2. In mechanical engineering and machine tool manufacturing. The special shape determines high rigidity and the ability to absorb vibration loads. That is why the material in question is used to create a reinforcing frame, supporting frame and other elements.

The wide scope of application has determined that on sale you can find a corner with various shapes profile and dimensions.

State standards for corners

As previously noted, a system of standardization of key indicators is used in production. For example, GOST 8509-93 (hot-rolled equal flange steel angles) determines the geometric dimensions of the profile: radius of curvature, flange thickness and other indicators. The designation of various parameters allows for accurate calculations during design.

Download GOST 8509-93 “Hot-rolled equal flange steel angles. Assortment."

As a result of calculations for strength and rigidity, it is necessary to make a decision on the choice of profile - angle number.


The table of corner parameters is used when solving problems of eccentric compression, determining geometric characteristics and solving many other practical problems where it is necessary to select a corner whose parameters satisfy the conditions of strength and rigidity. The range of angles is varied (2-3 times more options than channels and I-beams), so making a design decision will not be so difficult. You should always try to choose the smallest possible angle number in order to reduce weight and size, but at the same time the specified conditions must be met. If the characteristics of the corner are inferior to the calculated ones by less than 5% (for example, the axial moment of inertia relative to one of the main central axes), then the corresponding number of the corner is taken, if more than 5%, then the next number of the corner is taken.

The corner drawing (image above) shows the main geometric dimensions, which are reflected in the angle assortment table. In addition to geometric parameters assortment of corners contains:

geometric characteristics:

• axial moments of inertia angle relative to horizontal and vertical axes
• passing through the center of gravity
• matching the profile contour
• corner radius of gyration relative to the main central axes
• weight per linear meter of angle
• sectional area of ​​the angle profile

Hint: The centrifugal moment of inertia of the angle is 0 relative to the main central axes (which are shown at an angle of 45° in the drawing). Therefore, when solving practical problems, it is convenient to work with these axes.

The modern construction industry has a constant demand for different kinds profiles, especially equal-angle angles. This is understandable. Despite the simplicity of the form, it combines such qualities as increased specific strength, ease of welding, and low cost. Structures, subject to design rules, are characterized by rigidity and relatively low weight compared to the same rod.

Types of corners

An equal angle corner consists of two sheets of the same width connected to each other at an angle of 90 degrees. The materials used for manufacturing are various types of steel and aluminum alloys. Magnesium alloys are used less frequently in the manufacture of corners. The corners are completely standardized. Their standard sizes, production method and composition are determined by the relevant GOSTs.

The range of corner profiles is divided based on the following features:

• Manufacturing technology (rolled and bent).
• Type of material used.

Let us now consider each point in more detail.

Bent corner equal flange

The range of bent corner profiles is regulated by GOST 19771-93. Its peculiarity is obtaining the required shape by bending. This process is a type of cold forming. To carry out this operation, standard stamping and pressing equipment is used.

This type of production leaves its mark on the strength and parameters of the corner. Among them, it is worth noting the low productivity of the bending line in comparison with the rolling line. The number of meters obtained during bending is approximately 5-8 times lower, depending on the type of model of equipment used.

Also, the second disadvantage of bent profiles is the difficulty, and in some cases the impossibility, of obtaining thick-walled corners. Significant stresses arising during this process contribute to the formation of cracks, and, consequently, a sharp decrease in the load-bearing capacity of the angle. Therefore, other things being equal, it is preferable to produce thick-walled corner profiles by rolling.

In addition, the angle obtained by bending is limited in length, unlike the rolled one. This parameter is within the dimensions of the matrix and cannot go beyond it.

Among the advantages of the bending line is its high versatility. Less time and financial costs are required to re-adjust the production of angles with other sizes.

Also, stamping equipment has significantly smaller dimensions and, importantly, cost compared to rolling equipment. Based on the above, it turns out that this type of manufacturing technology is more suitable for enterprises with low production volumes.

During cold forming, metal deformation occurs exclusively at the bend of the angle. Together with the lack of exposure to elevated temperatures, this has a positive effect on the overall cleanliness of the surface and, accordingly, the appearance of the corners.

Due to all of the above, equal-flange bent angles have found greater use in the production of household appliances, cladding of load-bearing structures and lighting technology. It can also be partially found in the production of small-sized machines and mechanisms. That is, in those areas where appearance and aesthetics are paramount and a large length of the corner is not required.

Hot Rolled Steel Equal Angle

It is obtained by rolling. The range of sizes and strength characteristics are regulated by GOST 8509-93.

A feature of the rolling process is continuity, which significantly increases its productivity. The downside of this coin is low versatility, which means time-consuming readjustment of equipment for the production of angles with other dimensional characteristics. Also, a rolling line is significantly superior to a stamping line in terms of cost and labor intensity in setting up equipment.

The rolling method makes it possible to obtain an assortment of corner profiles of almost unlimited length. The length depends solely on the size of the production room.

Preheating of rolled products makes it possible to use more massive workpieces and, accordingly, obtain angles with a thicker wall thickness (over 6 mm). This increase in cross-sectional area helps to increase strength and resistance to deformation.

When hot rolling, the steel grain size is refined, which has a positive effect on the overall rigidity of the angle. Although it is worth noting, these processes do not significantly increase the tendency of the corner profile to form cracks and significantly worsen its appearance.

Based on the information presented above, it is not difficult to guess that hot-rolled angles are mainly used in the manufacture of load-bearing structural elements and industrial equipment. This includes various overpasses, metal frames of premises, scaffolding. In other words, places where increased rigidity is required and there are no high requirements for appearance.

Types of materials

Depending on the requirements for weight, rigidity and appearance, the following types of materials are used for manufacturing:

• Steel;
• Aluminum;
• Magnesium alloys.

The majority of the entire blanking industry (about 75%) is made up of angle profile assortments, the material of which is regular quality carbon steel. This material is regulated by GOST 380-2005.

The composition of carbon steels consists of iron and carbon, with a small (less than 1%) presence of manganese and silicon. Also, they are not subject to high requirements for the content of harmful impurities such as phosphorus and sulfur. But with all this, such steel has sufficient strength, machinability and, most importantly, cost for this area. The most popular grade in the production of metal structures from this type of steel is St3.

Also often the material for equal angles is construction steel, type C255 and C245. Their mechanical properties And chemical composition regulated by GOST 2772-88. Compared to carbon steels of ordinary quality, they are subject to increased requirements for the content of impurities.

In the presence of higher loads, a range of profiles made of high-strength rolled steel is used (GOST 19281-89). They are distinguished by an increased content of manganese, aluminum and silicon in their composition.

In critical metal structures - bridges, long-span crane beams - a range of angles made from low-alloy rolled steel GOST 19281-89 is used. Such as 15HSND. They are distinguished by a higher carbon content, and are also additionally alloyed with chromium, nickel and silicon.

In conditions where greater demands are placed on aesthetic properties and corrosion resistance, corners based on aluminum alloys are used. They are made from both structural aluminum and duralumin. The properties and chemical composition of the material are fully described by GOST 4884-76 and GOST 4784-76.

The use of magnesium alloys has a similar purpose as aluminum alloys. But due to their high cost, their use is becoming increasingly rare in industry.

Corner profile parameters

The main parameters that should be taken into account when choosing a corner assortment are the thickness and size of the shelf. It is their value that largely determines the cross-sectional area, which in turn determines the strength of the structure.

An insufficiently rigid corner is deformed under the influence of loads, which leads, if not to complete, then, as a rule, to partial loss of the structure’s functionality. An increased safety margin is also undesirable due to the ineffectiveness of using metal: increased weight and cost of the structure.

Also no less important parameters are:

• Curve radius between flanges. The higher its value, the better for the mechanical characteristics of the angle due to the presence of increased stresses here. It is in this place that primary traces of destruction appear.
• The rounding radius of the edges of the shelves is necessary to reduce stress concentration.
• Moment and radius of inertia - these parameters are necessary to determine the maximum load that the corner can withstand. They characterize the stability of the profile geometry directly to resist the effects of deformation. These parameters are indicated in special tables of the standard assortment.
• Profile length. Products are supplied in lengths from 3 to 12 meters, but by prior agreement between the supplier and the customer they can be supplied in larger sizes.