home Heating calculation Hot-rolled fittings for reinforcing reinforced concrete structures. Hot rolled steel for reinforcement of reinforced concrete structures Technical specifications GOST 5781 82

Hot-rolled fittings for reinforcing reinforced concrete structures. Hot rolled steel for reinforcement of reinforced concrete structures Technical specifications GOST 5781 82

GOST 5781-82

Developed by State
Committee of the Russian Federation for Standardization
and metrology

HOT-ROLLED STEEL FOR REINFORCEMENT OF REINFORCED CONCRETE STRUCTURES

Specifications

This standard applies to hot-rolled round steel of smooth and periodic profiles intended for the reinforcement of ordinary and prestressed reinforced concrete structures(reinforcing steel).
Regarding the standards for the chemical composition of low-alloy steels, the standard also applies to ingots, blooms and billets.
(Changed edition, Amendment No. 4).

1. CLASSIFICATION AND ASSORTMENT

1.1. Depending on the mechanical properties reinforcing steel is divided into classes A-I (A240), A-I (AZOO), A-III (A400); A-IV (A600), A-V (A800), A-VI (A1000).
1.2. Reinforcing steel is manufactured in bars or coils. Reinforcing steel class A-I(A240) are made smooth, classes A-I I (A300), A-III (A400), A-IV (A600); A-V (A800) and A-VI (A1000) - periodic profile.
At the request of the consumer, steel of classes A-II (A300), A-III - (A400), A-IV (A300) l A-V (A800) is made smooth,
1.1; 1.2. (Changed edition, Amendment No. 5).
1.3. Profile numbers, cross-sectional areas, weight of 1 m length of reinforcing steel of smooth and periodic profiles, as well as maximum mass deviations for periodic profiles must correspond to those indicated in the table. 1.
1.4. The nominal diameters of periodic profiles must correspond to the nominal diameters of smooth profiles of equal cross section area.

Table 1

Profile number	Square cross section, cm 2	Weight of 1 m profile
Profile number	Square cross section, cm 2	Theoretical, kg	Maximum deviations, %
6 8	0,283 0,503	0,222 0,395	+9,0; -7,0
10 12 14	0,785 1,131 1,540	0,617 0,888 1,210	+ 5,0; - 6,0
16 18 20 22 25 28	2,010 2,540 3,140 3,800 4,910 6,160	1,580 2,000 2,470 2,980 3,850 4,830	+ 3,0; -5,0
32 36 40 45	8,040 10,180 12,570 15,000	6,310 7,990 9,870 12,480	+ 3,0; -4,0
50 55 60 70 80	19,630 23,760 28,270 38,480 50,270	15,410 18,650 22,190 30,210 39,460	+2,0; -4,0

(Changed edition, Amendment No. 3)
1.5. The mass of 1 m of profile is calculated based on the nominal dimensions with a steel density of 7.85 g/cm 3 . The probability of providing a mass of 1 m must be at least 0.9.

1.6. The maximum deviations of the diameter of smooth profiles must comply with GOST 2590-88 for normal rolling accuracy.
1.7. Periodic profile reinforcing steel is a round profile with two longitudinal ribs and transverse projections running along a three-lead helix. For profiles with a diameter of 6 mm, protrusions running along a single-start helical line are allowed, with a diameter of 8 mm - along a double-start helical line.
1.8. Reinforcing steel class A-I I (A300), manufactured in a conventional design, with the profile shown in Fig. 1a and special purpose Ac-II (Ac300) with the profile shown in Fig. 2a, must have protrusions running along helical lines with the same approach on both sides of the profile.
Steel class A-III (A400), manufactured with the profile shown in Fig. 1b, and classes A-I V (A600), A-V (A800), A-VI (A 1000) with the profile shown in Fig. 1b, 2b, should have protrusions along helical lines that have right entries on one side of the profile and left entries on the other.
Reinforcing steel for special purposes of class Ac-II (Ac300) is made with profiles shown in Fig. 1a or 2a.
The profile shown in Fig. 2a, for special purposes is manufactured by agreement between the manufacturer and the consumer. The shape and dimensions of the profiles shown in Fig. 2a and b may be specified.
1.9. The dimensions and maximum deviations of the dimensions of reinforcing steel of periodic profile, manufactured according to Fig. 1a and b, must correspond to those given in table. 2, but damn. 2 a and b - given in table. 3.
1.10. Relative displacements of helical protrusions on the sides of the profile, separated by longitudinal ribs, are not standardized.
Dimensions for which maximum deviations are not established are given for caliber construction and are not checked on the finished profile.
1.11. The ovality of smooth profiles (the difference between the largest and smallest diameters in one section) should not exceed the sum of the plus and minus maximum deviations along the diameter.
1.9.-1.11. (Changed edition, Amendment No. 3).
1.12. Reinforcing steel of classes A-I (A240) and A-II (A300) with a diameter of up to 12 mm and class A-III (A400) with a diameter of up to 10 mm inclusive, is produced in coils or rods, large diameters - in rods. Reinforcing steel of classes A-IV (A600), A-V (A800) and A-VI (АУОО) of all sizes is produced in rods, with a diameter of 6 and 8 mm, produced, by agreement between the manufacturer and the consumer, in coils.
1.13. The rods are made from 6 to 12 m long:
- measured length;
- measured length with unmeasured segments - length of at least 2 m, not more than 15% of the lot weight;
- of unmeasured length.
In a batch of rods of unmeasured length, the presence of rods with a length of 3 to 6 m is allowed, no more than 7% of the mass of the batch.

Profile number (nominal diameter dн)	d		h		d1	h1	t	b	b1	r
	Nom.	Prev. off	Nom.	Prev. off
6 8 10 12 14 16 18 20 28 32 36 40 45 50 70 80	5,75 7,5 9,3 11,0 13,0 15,0 17,0 19,0 21,0 24,0 26,5 30,5 34,5 38,5 43,0 48,0 53,0 58,0 68,0 77,5		0,5 0,75 1,0 1,25 1,25 1,5 1,5 1,5 1,5 1,5 2,0 2,0 2,5 2,5 3,0 3,0 3,0 3,0 3,0 3,0	±0.25 ±0.25 ±0.5 ±0.5 ±0.5 ±0.5 ±0.5 ±0.5 ±0.5 ±0.5 ±0.7 ±0.7 ±0.7 ±0.7 ±0.7 ±0.7 ±1.0 ±1.0 ±1.0 ±1.0	6,75 9,0 11,3 13,5 15,5 18,0 20,0 22,0 24,0 27,0 30,5 34,5 39,5 43,5 49,0 54,0 59,0 64,0 74,0 83,5	0,5 0,75 1,0 1,25 1,25 1,5 1,5 1,5 2,0 2,0 2,5 2,5 3,0 3,0 3,0 3,0	5 5 7 7 7 8 8 8 9 10 12 12 15 15 15 15	0,5 0,75 1,0 1,0 1,0 1,5 1,5 1,5 1,5 2,0 2,0 2,0 2,5 2,5 2,5 2,5	1,0 1,25 1,5 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,5 3,0 3,0 3,0 3,5 3,5 4,5 4,5	0,75 1,1 1,5 1,9 1,9 2,2 2,2 2,2 3,0 3,0 3,5 3,5 4,5 4,5 5,5 5,5
		+0,4 - 0,5

		+0,4 - 1,0
		+0,5 - 1,1

Note. At the request of the consumer, maximum deviations of size d1 should not exceed maximum deviations d plus double maximum deviations h. By agreement between the manufacturer and the consumer, it is possible to manufacture rods from 5 to 25 m.
1.14. The maximum deviations for the length of the measuring rods must correspond to those given in the table. 4

Profile number
(nominal
diameter dн)

angle, degree

Nom.

Prev. off

Nom.

Prev. off

10
12
14
16
18
20

28
32
36
40

8,7
10,6
12,5
14,2
16,2
18,2

20,3
23,3

25,9
29,8
33,7
37,6

1,6
1 ,6
2,0
2,5
2,5
2,5

2,5
2,5

3,0
3,2
3,5
3,5

±0.5
±0.5
+0,65 - 0,85
+0,65 - 0,85
+0,65 - 0,85
+0,65 - 0,85

0,65 - 0,85
+0,65 - 0,85

1,0 - 1,2
+1,0 - 1,2
+1,0 - 1,2
+1,0 - 1,2

11,9
13,8
16,5
19,2
21,2
23,2

25,3
28,3

31,9
36,2
40,7
44,6

1,6
1,6
2","0
2,5
2,5
2,5

2,5
2,5

3,0
3,2
3 5
3,5

0,6
0,6
0,8
1,0
1,0
1,0

1, 2
1,2
1,5
1,5

1,0
1,0
1,2
1,5
1,5
1,5

1,8
2,0
2,0
2,0

10
10
12
12
12
12

14
16
18
18

0,7
0,7
1,0
1,0
1,0
1,0

1,0
1,2

1,2
1,5
1,5
1,5

1,5
2,0
2,0
2,0
2,0
2,0

2,5
3,0
3,0
3,0

11
11
12
12
12
12

14
14
19
19

+0,4
- 0,5

High-precision rods are manufactured according to customer requirements.
1.15. The curvature of the rods should not exceed 0.6% of the measured length.

Examples of symbols

Reinforcing steel with a diameter of 20 mm, class A-II (A300): 20 - A-II GOST 5781-82

Reinforcing steel with a diameter of 18 mm, class A-I (A240): 18 - A-I GOST 5781-82.

In the designation of rods class A-P(A300) special purpose index is added with: Ac-II (Ac300)
(Changed edition, Amendment No. 4)

2. TECHNICAL REQUIREMENTS

2.1. Reinforcing steel is manufactured in accordance with the requirements of this standard according to technological regulations approved in the prescribed manner.
2.2. Reinforcing steel is made from carbon and low-alloy steel of the grades indicated in table. 5. The steel grade is indicated by the consumer in the order. If there is no indication, the steel grade is determined by the manufacturer. For class A-IV (A600) rods, steel grades are established by agreement between the manufacturer and the consumer.

Reinforcing steel class	Profile diameter, mm	steel grade
A-I (A240)	6-40	StZkp, StZps, StZsp
A-II (A300)	10-40 40-80	St5sp, St5ps 18G2S
Ac-II (Ac300)	10-32 (36-40)	10GT
A-III (A400)	6-40 6-22	35GS, 25G2S 32G2Rps
A-IV (A600)	10-18 (6-8)	80C
A-IV (A600)	10-32 (36- 40)	20ХГ2Ц
A-V (A800)	(6-8) 10-32 (36-40)	23Х2Г2Т
A-VI (A1000)	10-22	22Kh2G2AYu, 22Kh2G2R, 20Kh2G2SR

1. Production of reinforcing steel is allowed class A-V(A800) from steel grades 22Kh2G2AYU, 22Kh2G2R. and 20Kh2G2SR.
2. The dimensions indicated in brackets are manufactured by agreement between the manufacturer and the consumer.
(Changed edition, Rev., No. 3, 4).

2.3. The chemical composition of reinforcing carbon steel must comply with GOST 380-88, low-alloy steel - with the standards given in table 6.

Steel grades	Mass fraction of elements, %
Steel grades	Carbon	Manganese	Silicon	Chlorine
10GT 18G2S 32G2Rps 35GS 25G2S 20ХГ2Ц 80C 23Х2Г2Т 22Х2Г2АУ 22Х2Г2Р 20X2G2SR	No more than 0.13 0,14-0,23 0,28-0,37 0,30-0,37 0,20-0,29 0,19-0,26 0,74-0,82 0,19-0,26 0,19- 0,26 0,19- 0,26 0,16-0,26	1,00-1,40 1,20-1,60 1,30-1,75 0,80- 1,20 1,20-1,60 1,50-1,90 0,50-0,90 1,40-1,70 1,40-1,70 1,50-1,90 1,40-1,80	0,45-0,65 0,60-0,90 No more than 0.17 0,60-0,90 0,60-0,90 0,40-0,70 0,60-1,10 0,40-0,70 0,40-0,70 0,40-0,70 0,75-1,55	No more than 0.30 No more than 0.30 Not more than 0.30 No more than.0.30 No more than 0.30 0,90-1,20 No more than 0.30 1,35-1,70 1,50-2,10 1,50-1,90 1,40-1,80

Steel grades	Mass fraction of elements, %
	Titanium	Zirconium	Aluminum	Nickel	Sulfur	Phosphorus	Copper
				No more
10GT 18G2S 32G2Rps 35GS 25G2S 20ХГ2Ц 80C 23Х2Г2Т 22Х2Г2АУ 22Х2Г2Р 20X2G2SR	0,015-0,03 - - - - - 0,015-0,040 0,02-0,08 0,005-0,030 0,02- 0,08 0,02-0,08	- - - - - 0,05-0,14 - - - - -	0,02-0,05 - 0,001-0,015 - - - - 0,015-0,050 0,02-0,07 0,015-0,050 6,015-0,050	- 0,30 0,30 0,30 0,30 0,30 0,30 0,30 0,30 0 ,30 0,30	0,040 0,045 0,050 0,045 0,045 0,045 0,045 0,045 0,040 0,040 0,040	0,030 0,040 0,045 0,040 0,040 0,045 0,040 0,045 0,040 0,040 0,040	0,30 0,30 0,30 0,30 0,30 0,30 0,30 0,30 0,30 0,30 0,30

2.3.1. In steel grade 20ХГ2Ц, it is allowed to increase the mass fraction of chromium to 1.7% and replace zirconium with 0.02-0.08% titanium. In steel grade 23Х2Г2Т, replacement of titanium by 0.05-0.10% is allowed. zirconium. In this case, in the designation of steel grade 20KhG2Ts, the letter T is used instead of the letter C; steel grade 23Kh2G2T is marked with the letter T instead of the letter T.
In steel grade 32G2Rps, aluminum can be replaced with titanium or zirconium in equal units. .
2.3.2. The mass fraction of nitrogen in steel grade 22Х2Г2АУ should be 0.015-0.030%, the mass fraction of residual nitrogen in steel grade 10GT should be no more than 0.008%.
2.3.3. The mass fraction of boron in steel grades 22Kh2G2R, 20Kh2G2SR and 32G2Rps should be 0.001-0.007%. In steel grade 22Х2Г2АУ, the addition of 0.001-0.008% boron is allowed.
2.3.4. It is allowed to add titanium to steel grades 18G2S, 25G2S, 35GS based on its mass fraction in finished rolled products of 0.01-0.03%, to steel grade 35GS based on its mass fraction in finished rolled products produced in coils of 0.01-0 .06%.
2.4 Deviations in chemical composition in finished rolled products from carbon steels - according to GOST 380-88, from low-alloy steels, subject to the standards of mechanical properties - according to Table. 7. Minus deviations in the content of elements (except for titanium and zirconium, and for the steel grade 20Kh2G2SR silicon) are not limited.

Note.

By agreement between the manufacturer and the consumer, steel can be produced with other deviations in the content of chromium, silicon and manganese.
(Changed edition, Amendment No. 3).

2.6. Reinforcing steel of classes A-I (A240), A-II (AZOO), A-III (A400), A-IV (A600) is produced by hot-rolled class. A-V(A800) - with low-temperature tempering, class A-VI (A1000) - with low-temperature tempering or thermomechanical processing in the flow of a rolling mill.
It is allowed not to carry out low-temperature1 tempering of steel of classes A-V (A800) and A-VI (A1000) provided that a relative elongation of at least 9% and a uniform elongation of at least 2% are obtained when tested within 12 hours after rolling.
2.6. The mechanical properties of reinforcing steel must comply with the standards specified in table. 8.
For steel class AII (A300) with a diameter of over 40 mm, a reduction in elongation of 0.5% is allowed for each millimeter increase in diameter, but not more than 3%.
For steel class Ac-II (Ac300), is it possible to reduce the tensile strength to 426 MPa (43.5 kgf/mm 2) with relative elongation? 5 30% or more.
For steel grade 25G2S class A-III (A400), a reduction in tensile strength to 560 MPa (57 kgf/mm 2) is allowed with a yield strength of at least 405 MPa (41 kgf/mm 2), relative elongation? 5 not less than 20%.
2.7. Statistical indicators of the mechanical properties of bars, periodic profile reinforcing steel must comply with Appendix 1, with increased uniformity of mechanical properties - Appendix 1 and Table. 9.
The probability of achieving the mechanical properties specified in Table 8 must be at least 0.95.
(Changed edition, Amendment No. 3).
2.8. On the surface of the profile, including the surface of the ribs and protrusions, there should be no rolled cracks, stress cracks, flaws, rolled films or sunsets.
Minor damage to the ribs and protrusions is allowed, in the amount of no more than three per 1 m of length, as well as minor rust, individual rolled-out contamination, prints, sagging, traces of rolled-out bubbles, rippling and scaliness within the limits of permissible deviations in size.
(Changed edition, Amendment No. 2).
2.9. Weldability of reinforcing steel of all grades, except 80C, is ensured chemical composition and manufacturing technology.
2.10. Carbon equivalent Ceq ? C+Mn/6 + Si/10 for welded rod reinforcement made of low-alloy steel of class A-III (A400) should be no more than 0.62.
(Introduced additionally, Amendment No. 5).

Class reinforcement become	Yield strength ? T		Temporary resistance rupture ? B		Relative extension ? 5 , %	Uniform elongation ? p, %	Percussion viscosity at temperature - 60 °C		Test for bend in the cold condition (c - thickness of the mandrel, d - diameter of the rod)
	N/mm 2	kgf/mm 2	N/mm 2	kgf/mm 2			Mj/m 2	kgf*m/cm 2
	no less
A-I (A240) A-II (A300) Ac-II (A300) A-II (A400) A-IV (A600) A-V (A800) A-VI (A1000)	235 295 295 390 590 785 980	24 30 30 40 60 80 100	373 490 441 590 883 1030 1230	38 50 45 60 90 105 125	25 19 25 14 6 7 6	- - - - 2 2 2	- - 0,5 - - - -	- - 5 - - - -	180°; c=d 180°; c = 3d 180°; c =d 90°; c = 3d 45°; c = 5d 45°; c = 5d 45°; c=5d

Notes:

1. By agreement between the manufacturer and the consumer, it is allowed not to test the impact strength of class Ac-II reinforcing steel.
2. (Deleted, Amendment No. 3).
3. For reinforcing steel of class A-IV with a diameter of 18 mm, steel grade 80C, the cold bending rate is set to at least 30°.
4. For reinforcing steel of class A-I (A240) with a diameter of over 20 mm when bending in a cold state by 180° c = 2 d, class A-II (A300) with a diameter of over 20 mm c = 4 d.
5. Symbols for the class of reinforcing steel according to yield strength are indicated in brackets.
(Changed edition, Amendment No. 1, 3, 5).

Class reinforcement become	Number profile	S		So		S/x 1		So/x 2
		For? T (? 0,2)	For? B	For? T (? 0,2)	For? B	For? T (? 0,2)	For? B	For? T (? 0,2)	For? B
		MPa (kgf/mm 2)		MPa (kgf/mm 2)
		no more
A-II (A300) A-II (A400) A-IV (A600) A-V (A800) A-VI (A1000)	10-40 6-40 10-32 10-32 10-32	29(3) 39(4) 69(7) 78(8) 88(9)	29(3) 39(4) 69(7) 78(8) 88(9)	15(1,5) 20(2,0) 39(4) 49(5) 49(5)	15(1,5) 20(2,0) 39(4) 49(5) 49(5)	0,08 0,08 0,09 0,09 0,08	0,06 0,07 0,07 0,07 0,07	0,05 0,05 0,06 0,05 0,05	0,03 0,03 0,05 0,05 0,04

Note.

1. S - standard deviation in the general population of tests,
So - standard deviation in the melting batch,
x 1 - average value in the population of tests;
x 2 - minimum average value in the melting batch.
2. For reinforcing steel in coils with a diameter of 6 and 8 mm, it is allowed to increase the standards for S and So by 4.9 MPa (0.5 kgf/mm 2),
3. (Deleted, Amendment No. 5).

3. ACCEPTANCE RULES

3.1. Reinforcing steel is accepted in batches consisting of profiles of the same diameter, one class of one melt-ladle and issued with one quality document.
The batch weight should be up to 70 tons.
It is allowed to increase the mass of the batch to the mass of the melting ladle.
3. 2. Each batch is accompanied by a quality document in accordance with GOST 7566-81 with additional data:
profile number;
Class;
minimum average value x 2 and standard deviations S 0 in a batch of values? T(? 0.2) and? B ;
results of cold bending tests;
values of uniform elongation for steel classes A - IV (A600), A-V (800), A-VI (A1000).
3. 3. To check the size and quality of the surface, select:
in the manufacture of reinforcing steel in rods - at least 5% of the batch;
when produced in skeins - two skeins from each batch.
(Changed edition, Amendment No. 3).
3 4. To check the chemical composition, samples are taken according to GOST 7565-81.
The manufacturer determines the mass fraction of aluminum periodically, but at least once a quarter.
3.5. To test for tensile, bending and impact strength, two rods are selected from the batch
For the manufacturing enterprise, the interval for selecting rods must be at least half the time spent on rolling one profile size of one batch
(Changed edition, Amendment No. 3).
3 6 If unsatisfactory test results are obtained for at least one of the indicators, repeated tests are carried out in accordance with GOST 7566-81.

4. TEST METHODS

4. 1. Chemical analysis steel is carried out according to GOST 12344-88, GOST 12348-78, GOST 12350-78, GOST 12352-81, GOST 12355-78, GOST 12356-81, GOST 18895-81 or other methods that ensure the required accuracy.
4. 2. The diameter and ovality of the profiles are measured at a distance of at least 150 mm from the end of the rod or at a distance of no less than 1500 mm from the end of the skein with a skein weight of up to 250 kg and at least 3000 mm with a skein weight of more than 250 kg.
4. 3. Dimensions are checked measuring instrument required accuracy.
4. 4. One sample is cut from each selected rod for testing tensile, bending and impact strength.
4.5. Sampling for testing tensile, bending and impact strength is carried out according to GOST 7564-73
4.6. The tensile test is carried out according to GOST 12004-81.
4.7. The bending test is carried out according to GOST 14019-80 on samples with a cross-section equal to the cross-section of the rod
For rods with a diameter over 40 mm, it is allowed to test samples cut along the axis of the rod on a mandrel with a diameter reduced by half compared to that indicated in the table. 4, with bending force applied from the side of the cut.
4.8. Determination of impact strength is carried out according to GOST 9454-78 on samples with a concentrator type U type 3 for rods with a diameter of 12-14 mm and samples of type 1 for rods with a diameter of 16 mm or more. Samples are manufactured in accordance with the requirements of GOST 9454-78.
4.9. It is allowed to use statistical and non-destructive methods for monitoring the mechanical properties and mass of profiles.
4.10. The curvature of the rods is measured along the length of the supplied profile, but not shorter than 1 m.
4.11. Determination of statistical indicators of mechanical properties in accordance with mandatory Appendix 2.
4.12. The quality of the surface is checked without the use of magnifying devices.
4.10-4.12. (Introduced additionally, Amendment No. 3).
4.13. The height of the transverse projections of a periodic profile should be measured along the vertical axis of the cross-section of the reinforcing bars.
(Introduced additionally, Amendment No. 4).

5. PACKAGING, LABELING, TRANSPORTATION AND STORAGE

5.1. Packaging, labeling, transportation and storage - in accordance with GOST 7566-81 with additions: .
the ends of rods made of low-alloy steels of class A-IV (A600) must be painted with red paint, class A-V - red and green, class A-VI (A1000) - red and blue. It is allowed to paint the ligaments at a distance of 0.5 m from the ends;

the rods are packaged in bundles weighing up to 15 tons, tied with wire or wire rod. At the consumer's request, the rods are packaged in bundles weighing up to 3 and 5 tons.

On ties, paint is applied in strips no less than 20 mm wide on the side surface around the circumference (at least 1/2 the length of the circumference) at a distance of no more than 500 mm from the end.

Paint is applied to skeins in strips no less than 20 mm wide across the turns on the outside of the skein.
For unpackaged products, paint is applied to the end or side surface at a distance of no more than 500 mm from the end.
The label attached to each bundle of bars bears the accepted designation of the class of reinforcing steel (for example, A-III) or symbol yield strength class (A400).
(Changed edition, Amendment No. 3, 5).

GOST 5781-82

INTERSTATE STANDARD

HOT-ROLLED STEEL
FOR REINFORCEMENT
REINFORCED CONCRETE STRUCTURES

TECHNICAL CONDITIONS

Date of introduction 07/01/83

This standard applies to hot-rolled round steel of smooth and periodic profiles intended for the reinforcement of ordinary and prestressed reinforced concrete structures (reinforcing steel).

Regarding the standards for the chemical composition of low-alloy steels, the standard also applies to ingots, blooms and billets.

1. CLASSIFICATION AND ASSORTMENT

1.1. Depending on the mechanical properties, reinforcing steel is divided into classes A-I (A240), A-II (A300), A-III (A400), A-IV (A600), A-V (A800), A-VI (A1000).

1.2. Reinforcing steel is manufactured in bars or coils. Reinforcing steel of class A-I (A240) is made smooth, classes A-II (A300), A-III (A400), A-IV (A600), A-V (A800) and A-VI (A1000) - periodic profile.

At the request of the consumer, steel of classes A-II (A300), A-III (A400), A-IV (A600) and A-V (A800) is made smooth.

1.1, 1.2. (Changed edition, Amendment No. 5).

1.3. Profile numbers, cross-sectional areas, weight of 1 m length of reinforcing steel of smooth and periodic profiles, as well as maximum mass deviations for periodic profiles must correspond to those indicated in the table. 1.

Table 1

Profile number (nominal rod diameter d n)	Cross area rod cross-section, cm 2	Weight of 1 m profile
Profile number (nominal rod diameter d n)	Cross area rod cross-section, cm 2	Theoretical; kg	Limit deviations, %
6	0,283	0,222	+9,0
8	0,503	0,395	-7,0
10	0,785	0,617	+5,0
12	1,131	0,888
14	1,540	1,210
16	2,010	1,580	+3,0-5,0
18	2,540	2,000
20	3,140	2,470
22	3,800	2,980
25	4,910	3,850
28	6,160	4,830
32	8,040	6,310	+3,0
36	10,180	7,990
40	12,570	9,870
45	15,000	12,480
50	19,630	15,410	+2,0
55	23,760	18,650
60	28,270	22,190
70	38,480	30,210
80	50,270	39,460

1.4. The nominal diameters of periodic profiles must correspond to the nominal diameters of smooth profiles of equal cross-sectional area.

1.5. The mass of 1 m of profile is calculated based on the nominal dimensions with a steel density equal to 7.85 × 10 3 kg/m 3. The probability of providing a mass of 1 m must be at least 0.9.

(Changed edition, Amendment No. 3).

1.6. Maximum deviations of the diameter of smooth profiles must comply with GOST 2590 for normal rolling accuracy.

1.7. Periodic profile reinforcing steel is a round profile with two longitudinal ribs and transverse projections running along a three-lead helix. For profiles with a diameter of 6 mm, protrusions running along a single-start helical line are allowed, with a diameter of 8 mm - along a double-start helical line.

1.8. Reinforcing steel of class A-II (A300), manufactured in a conventional design, with a profile shown in Fig. 1 a, and special purpose Ac-II (Ac300) profile shown in Fig. 2 A, must have protrusions running along helical lines with the same approach on both sides of the profile.

Steel class A-III (A400), manufactured with the profile shown in Fig. 1 b, and classes A-IV (A600), A-V (A800), A-VI (A1000) with the profile shown in Fig. 1 b, 2b, must have protrusions along helical lines that have right-hand entries on one side of the profile and left-hand entries on the other.

Reinforcing steel for special purposes of class Ac-II (Ac300) is made with profiles shown in Fig. 1 a or 2 A.

The profile shown in Fig. 2 A, for special purposes are manufactured by agreement between the manufacturer and the consumer. The shape and dimensions of the profiles shown in Fig. 2 A, b, may be specified.

1.9. Dimensions and maximum deviations in dimensions of reinforcing steel of periodic profile, manufactured according to drawing. 1 a, b, must correspond to those given in table. 2, but damn. 2 A, b- given in table. 3.

table 2

Dimensions, mm

Profile number (nominal diameter d n)	d		h		d 1	h 1	l	b	b 1	r
Profile number (nominal diameter d n)	Nom.	Prev. off	Nom.	Prev. off	d 1	h 1	l	b	b 1	r
6	5,75		0,5	±0.25	6,75	0,5	5	0,5	1,0	0,75
8	7,5		0,75	±0.25	9,0	0,75	5	0,75	1,25	1,1
10	9,3		1,0		11,3	1,0	7	1,0	1,5	1,5
12	11,0	+0,3	1,25		13,5	1,25			2,0	1,9
14	13,0	-0,5	1,25		15,5	1,25				1,9
16	15,0		1,5		18,0	1,5	8	1,5		2,2
18	17,0			±0.5	20,0
20	19,0				22,0
22	21,0	+0,4			24,0
25	24,0	-0,5			27,0
28	26,5		2,0		30,5	2,0	9		2,5	3,0
32	30,5		2,0		34,5	2,0	10	2,0	3,0	3,0
36	34,5	+0,4	2,5	±0.7	39,5	2,5	12			3,5
40	38,5	-0,7	2,5		43,5	2,5	12			3,5
45	43,0		3,0		49,0	3,0	15	2,5	3,5	4,5
50	48,0				54,0				3,5
55	53,0	+0,4			59,0				4,0
60	58,0	-1,0		±1.0	64,0				4,0	5,0
70	68,0	+0,5			74,0				4,5	5,5
80	77,5	-1,1			83,5				4,5	5,5
Note. At the consumer's request, maximum size deviations d 1 should not exceed maximum deviations d plus double maximum deviations h.

Table 3

Dimensions, mm

Profile number (nominal diameter d n)	d		h		d 1	h 1	h r	h B	t	b	b 1	r 1	a
	Nom.	Prev. off	Nom.	Prev. off
10	8,7		1,6	±0.5	11,9	1,6	0,6	1,0	10	0,7	1,5	11
12	10,6				13,8						2,0
14	12,5	+0,3	2,0		16,5	2,0	0,8	1,2	12	1,0	2,0	12
16	14,2	-0,5	2,5		19,2	2,5	1,0	1,5
18	16,2			+0,65	21,2
20	18,2			-0,85	23,2								50
22	20,3	+0,4			25,3
25	23,3	-0,5			28,3				14	1,2		14
28	25,9		3,0		31,9	3,0	1,2	1,8			2,5
32	29,8	+0,4	3,2	+1,0	36,2	3,2		2,0	16	1,5	3,0	19
36	33,7	-0,7	3,5	-1,2	40,7	3,5	1,5		18
40	37,6				44,6

1.10. Relative displacements of helical protrusions on the sides of the profile, separated by longitudinal ribs, are not standardized.

Dimensions for which maximum deviations are not established are given for caliber construction and are not checked on the finished profile.

1.11. The ovality of smooth profiles (the difference between the largest and smallest diameters in one section) should not exceed the sum of the plus and minus maximum deviations in diameter.

1.9 — 1.11. (Changed edition, Amendment No. 3).

1.12. Reinforcing steel of classes A-I (A240) and A-II (A300) with a diameter of up to 12 mm and class A-III (A-400) with a diameter of up to 10 mm inclusive. manufactured in coils or rods, large diameters - in rods. Reinforcing steel of classes A-IV (A600), A-V (A800) and A-VI (A1000) of all sizes is produced in rods with a diameter of 6 and 8 mm - by agreement between the manufacturer and the consumer, in coils.

1.13. The rods are made from 6 to 12 m long:

— measured length;

- measured length with unmeasured sections of at least 2 m in length, not more than 15% of the lot weight;

- of unmeasurable length.

In a batch of rods of unmeasured length, the presence of rods from 3 to 6 in length and no more than 7% of the mass of the batch is allowed.

By agreement between the manufacturer and the consumer, it is allowed to produce rods with a length of 5 to 25 m.

1.14. Maximum deviations along the length of measuring rods must correspond to those given in table. 4.

Table 4

High-precision rods are manufactured according to customer requirements.

1.15. The curvature of the rods should not exceed 0.6% of the measured length.

Examples of symbols

Reinforcing steel with a diameter of 20 mm, class A-II (A300):

20-A-II GOST 5781-82

The same, with a diameter of 18 mm, class A-I (A240):

18-A-I GOST 5781-82

The index “c” is added to the designation of class A-II (A300) rods for special purposes: Ac-II (Ac300).

(Changed edition, Amendment No. 4).

2. TECHNICAL REQUIREMENTS

2.1. Reinforcing steel is manufactured in accordance with the requirements of this standard according to technological regulations approved in the prescribed manner.

2.2. Reinforcing steel is made from carbon and low-alloy steel of the grades indicated in table. 5. The steel grade is indicated by the consumer in the order. If there is no indication, the steel grade is determined by the manufacturer. For class A-IV (A600) rods, steel grades are established by agreement between the manufacturer and the consumer.

Table 5

Reinforcing steel class	Profile diameter, mm	steel grade
A-I (A240)	6-40	St3kp, St3ps, St3sp
A-II (A300)	10-40	St5sp, St5ps
A-II (A300)	40-80	1NG2S
Ac-II (Ac300)	10-32	10GT
Ac-II (Ac300)	(36-40)	10GT
A-III (A400)	6-40	35GS, 25G2S
A-III (A400)	6-22	32G2Rps
A-IV (A600)	10-18	80C
	(6-8)	80C
	10-32	20ХГ2Ц
	(36-40)	20ХГ2Ц
A-V (A800)	(6-8)	23Х2Г2Т
	10-32
	(36-40)
A-VI (A1000)	10-22	22Kh2G2AYu, 22Kh2G2R, 20Kh2G2SR

Notes:

It is allowed to manufacture reinforcing steel of class A-V (A800). Made from steel grades 22Kh2G2AYU, 22Kh2G2R and 20Kh2G2SR.
The dimensions indicated in brackets are manufactured by agreement between the manufacturer and the consumer.

(Changed edition, Amendment No. 3, 4).

2.3. The chemical composition of reinforcing carbon steel must comply with GOST 380, low-alloy steel - with the standards given in table. 6.

Table 6

steel grade	Mass fraction of elements, %
	Carbon	Manganese	Silicon	Chromium	Titanium	Zirconium	Aluminum	Nickel	Sulfur	Phosphorus	Copper
	Carbon	Manganese	Silicon	Chromium	Titanium	Zirconium	Aluminum	no more
10GT	No more than 0.13	1,00 — 1,40	0,45 — 0,65	No more than 0.30	0,015-0,035	—	0,02 — 0,05	—	0,040	0,030	0,30
18G2S	0,14 — 0,23	1,20 — 1,60	0,60 — 0,90		—		—	0,30	0,045	0,040
32G2Rps	0,28 — 0,37	1,30 — 1,75	No more than 0.17				0,001-0,015		0,050	0,045
35GS	0,30 — 0,37	0,80 — 1,20	0,60 — 0,90				—		0,045	0,040
25G2S	0,20 — 0,29	1,20 — 1,60	0,60 — 0,90							0,040
20ХГ2Ц	0,19 — 0,26	1,50 — 1,90	0,40 — 0,70	0,90-1,20		0,05 — 0,14				0,045
80C	0,74 — 0,82	0,50 — 0,90	0,60 — 1,10	No more than 0.30	0,015-0,040	—				0,040
23Х2Г2Т	0,19 — 0,26	1,40 — 1,70	0,40 — 0,70	1,35-1,70	0,02 — 0,08		0,015-0,050			0,045
22Х2Г2АУ		1,40 — 1,70		1,50-2,10	0,005-0,030		0,02 — 0,07		0,040	0,040
22Х2Г2Р		1,50 — 1,90		1,50-1,90	0,02 — 0,08		0,015-0,050
20X2G2SR	0,16 — 0,26	1,40 — 1,80	0,75 — 1,55	1,40-1,80	0,02 — 0,08		0,015-0,050

2.3.1. In steel grade 20ХГ2Ц, it is allowed to increase the mass fraction of chromium to 1.7% and replace zirconium with 0.02 - 0.08% titanium. In steel grade 23Х2Г2Т it is allowed to replace titanium with 0.05 - 0.10% zirconium. In this case, in the designation of steel grade 20KhG2Ts, the letter T is used instead of the letter C; steel grade 23Kh2G2T is marked with the letter T instead of the letter T.

In steel grade 32G2Rps, aluminum can be replaced with titanium or zirconium in equal units.

2.3.2. The mass fraction of nitrogen in steel grade 22Х2Г2АУ should be 0.015 - 0.030%, the mass fraction of residual nitrogen in steel grade 10GT should be no more than 0.008%.

2.3.3. The mass fraction of boron in steel grades 22Kh2G2R, 20Kh2G2SR and 32G2Rps should be 0.001 - 0.007%. In steel grade 22Х2Г2АУ, the addition of 0.001 - 0.008% boron is allowed.

2.3.4. It is allowed to add titanium to steel grades 18G2S, 25G2S, 35GS based on its mass fraction in finished rolled products 0.01 - 0.03%, to steel grade 35GS based on its mass fraction in finished rolled products produced in coils 0.01 - 0 .06%.

2.4. Deviations in the chemical composition in finished rolled products from carbon steels - according to GOST 380, from low-alloy steels, subject to compliance with the standards of mechanical properties - according to Table. 7. Minus deviations in the content of elements (except for titanium and zirconium, and for steel grade 20Kh2G2SR - silicon) are not limited.

Table 7

Element	Prev. off, %	Element	Prev. off, %
Carbon	+0,020	Sulfur	+0,005
Silicon	+0,050	Phosphorus	+0,005
Manganese	+0,100	Zirconium	+0,010
Chromium	+0,050	Zirconium	+0,010
Copper	+0,050	Titanium	±0.010
Note. By agreement between the manufacturer and the consumer, steel can be manufactured with other deviations in the content of chromium, silicon and manganese.

(Changed edition, Amendment No. 3).

2.5. Reinforcing steel of classes A-I (A240), A-II (A300), A-III (A400), A-IV (A600) is made hot-rolled, class A-V (A800) - with low-temperature tempering, class A-VI (A1000) — with low-temperature tempering or thermomechanical treatment in the flow of a rolling mill.

It is allowed not to carry out low-temperature tempering of steel classes A-V(A800) and A-VI (A1000) subject to obtaining a relative elongation of at least 9% and a uniform elongation of at least 2% when tested within 12 hours after rolling.

2.6. The mechanical properties of reinforcing steel must comply with the standards specified in table. 8.

Table 8

Reinforcing steel class	Yield strength σ t		Temporary tensile strength σ in		Relative elongation δ5,%	Uniform elongation d r, %		Impact strength at -60 °C		Bend and cold test ( With- thickness of the mandrel, d- diameter of the rod)
	N/mm 2	kgf/mm 2	N/mm 2	kgf/mm 2	Relative elongation δ5,%	Uniform elongation d r, %		MJ/m2	kgf × m/cm 2
	No less
A-I (A240)	235	24	373	38	25	—	—		—	180°; c = d
A-II (A300)	295	30	490	50	19		—		—	180°; With = 3d
Ac-II (Ac300)	295	30	441	45	25		0,5		5	180°; c = d
A-III (A400)	390	40	590	60	14		—		—	90°; With = 3d
A-IV (A600)	590	60	883	90	6	2				45°; With = 5d
A-V (A800)	785	80	1030	105	7
A-VI (A1000)	980	100	1230	125	6
Notes: 1. By agreement between the manufacturer and the consumer, it is allowed not to test the impact strength of class Ac-II reinforcing steel. 2. (Deleted, Amendment No. 3). 3. For reinforcing steel of class A-IV with a diameter of 18 mm, steel grade 80C, the cold bending rate is set to at least 30°. 4. For reinforcing steel class A-I (A240) with a diameter over 20 mm when cold bending 180° With = 2d, class A-II (A300) with a diameter of St. 20 mm With = 4d. 5. Symbols for the yield strength are indicated in parentheses.

(Changed edition, Amendment No. 1, 3, 5).

For steel class A-II (A300) with a diameter of St. 40 mm, it is allowed to reduce the relative elongation by 0.25% for each millimeter increase in diameter, but not more than 3%.

For steel class Ac-II (Ac300), a reduction in tensile strength to 426 MPa (43.5 kgf/mm 2) is allowed with a relative elongation of: δ 5 30% or more.

For steel grade 25G2S class A-III (A400), a reduction in tensile strength to 560 MPa (57 kgf/mm2) is allowed with a yield strength of at least 405 MPa (41 kgf/mm2), relative elongation δ5 of at least 20%.

2.7. Statistical indicators of the mechanical properties of reinforcing steel bars of periodic profile must correspond to Appendix 1, with increased uniformity of mechanical properties - Appendix 1 and Table. 9.

The probability of achieving the mechanical properties indicated in table. 8, must be at least 0.95.

(Changed edition, Amendment No. 3).

2.8. On the surface of the profile, including the surface of the ribs and protrusions, there should be no rolled cracks, stress cracks, flaws, rolled films or sunsets.

Minor damage to the ribs and protrusions is allowed, in the amount of no more than three per 1 m of length, as well as minor rust, individual rolled out stains, prints, sagging, traces of rolled out bubbles, rippling and scaliness within the permissible deviations in size.

(Changed edition, Amendment No. 2).

2.9. The weldability of reinforcing steel of all grades, except 80C, is ensured by the chemical composition and manufacturing technology.

2.10. Carbon equivalent for welded rod reinforcement made of low-alloy steel of class A-III (A400) should be no more than 0.62.

(Introduced additionally, Amendment No. 5).

Table 9

Reinforcing steel class	Profile number	S		S 0
		For σ t (σ 0.2)	For σ in	For σ t (σ 0.2)	For σ in	For σ t (σ 0.2)	For σ in	For σ t (σ 0.2)	For σ in
		MPa (kgf/mm 2)		MPa (kgf/mm 2)
		No more
A-II (A300)	10-10	29(3)	29(3)	15(1,5)	15(1,5)	0,08	0,06	0,05	0,03
A-III (A400)	6-40	39(4)	39(4)	20(2,0)	20(2,0)		0,07
A-IV (A600)	10-22	69(7)	69(7)	39(4,0)	39(4)	0,09		0,06	0,05
A-V (A800)		78(8)	78(8)	49(5,0)	49(5,0)
A-VI (A1000)		88(9)	88(9)			0,08		0,05	0,04
Notes: 1. S— standard deviation in the general population of tests; S 0 - standard deviation in the melting batch; — average value in the population of tests; — the minimum average value in a batch-smelting. 2. For reinforcing steel in coils with a diameter of 6 and 8 mm, it is allowed to increase the standards for S And S 0 to 4.9 MPa (0.5 kgf/mm 2). 3. (Deleted, Amendment No. 5).

3. ACCEPTANCE RULES

3.1. Reinforcing steel is accepted in batches consisting of profiles of the same diameter, one class, one melt-ladle and issued with one quality document.

The batch weight should be up to 70 tons.

It is allowed to increase the mass of the batch to the mass of the melting ladle.

3.2. Each batch is accompanied by a quality document in accordance with GOST 7566 with additional data:

— profile number;

— minimum average value and standard deviations S 0 in the batch of values σ t (σ 0.2) and σ in;

— results of cold bending tests;

- values of uniform elongation for steel classes A-IV (A600), A-V (A800), A-VI (A1000).

3.3. To check the size and quality of the surface, select:

— in the manufacture of reinforcing steel in rods — at least 5% of the batch;

- during production and skeins - two skeins from each batch.

(Changed edition, Amendment No. 3).

3.4. To check the chemical composition, samples are taken according to GOST 7565.

The manufacturer determines the mass fraction of aluminum periodically, but at least once a quarter.

3.5. To test for tensile, bending and impact strength, two rods are selected from the batch.

For the manufacturer, the interval for selecting rods must be at least half the time spent on rolling one profile size of one batch.

(Changed edition, Amendment No. 3).

3.6. If unsatisfactory test results are obtained for at least one of the indicators, repeated tests are carried out in accordance with GOST 7566.

4. TEST METHODS

4.1 Chemical analysis of steel is carried out according to GOST 12344, GOST 12348, GOST 12350, GOST 12352, GOST 12355, GOST 12356, GOST 18895 or other methods that provide the required accuracy.

4.2. The diameter and ovality of the profiles are measured at a distance of at least 150 mm from the end of the rod or at a distance of at least 1500 mm from the end of the skein with a skein weight of up to 250 kg and at least 3000 mm with a skein weight of more than 250 kg.

4.3. Dimensions are checked with a measuring tool of the required accuracy.

4.4. One sample is cut from each selected rod for tensile, bending and impact strength testing.

4.5. Sampling for testing tensile, bending and impact strength is carried out in accordance with GOST 7564.

4.6. The tensile test is carried out according to GOST 12004.

4.7. The bending test is carried out according to GOST 14019 on samples with a cross-section equal to the cross-section of the rod.

For rods with a diameter over 40 mm, it is allowed to test samples cut along the axis of the rod on a mandrel with a diameter reduced by half compared to that indicated in the table. 4, with bending force applied from the side of the cut.

4.8. Determination of impact strength is carried out according to GOST 9454 on samples with a concentrator type U type 3 for rods with a diameter of 12 - 14 mm and samples of type 1 for rods with a diameter of 16 mm or more. Samples are manufactured in accordance with the requirements of GOST 9454.

4.9. It is allowed to use statistical and non-destructive methods for monitoring the mechanical properties and mass of profiles.

4.10. The curvature of the rods is measured along the length of the supplied profile, but not shorter than 1 m.

4.11. Determination of statistical indicators of mechanical properties in accordance with mandatory Appendix 2.

4.12. The quality of the surface is checked without the use of magnifying devices.

4.10 — 4.12. (Introduced additionally, Amendment No. 3).

4.13. The height of the transverse projections of a periodic profile should be measured along the vertical axis of the cross-section of the reinforcing bars.

(Introduced additionally, Amendment No. 4).

5. PACKAGING, LABELING, TRANSPORTATION AND STORAGE

5.1. Packaging, labeling, transportation and storage - in accordance with GOST 7566 with the following additions:

— the ends of rods made of low-alloy steels of class A-IV (A600) must be painted with red paint, class A-V - red and green, class A-VI (A1000) - red and blue. It is allowed to paint the ligaments at a distance of 0.5 m from the ends;

— the rods are packaged in bundles weighing up to 15 tons, tied with wire or wire rod. At the consumer's request, the rods are packaged in bundles weighing up to 3 and 5 tons;

On the ties, paint is applied in strips no less than 20 mm wide on the side surface around the circumference (at least 1/2 the length of the circumference) at a distance of no more than 500 mm from the end.

Paint is applied to the skeins in strips no less than 20 mm wide across the turns on the outside of the skein.

For unpackaged products, paint is applied to the end or side surface at a distance of no more than 500 mm from the end.

The label attached to each bundle of rods is marked with the accepted designation of the reinforcing steel class (for example, A-III) or the symbol of the yield strength class (A400).

(Changed edition, Amendment No. 3, 5).

ANNEX 1
Mandatory

REQUIREMENTS FOR STATISTICAL INDICATORS OF MECHANICAL PROPERTIES

≥ Xi b p + t × S;

> 0,9Xi b p + 3 S 0 ;

≥Xi b p,

Where Xiбp— rejection values of σ in, σ 0.2, indicated in table. 8 of this standard;

t— quantile value taken equal to 2 for classes A-II (A300) and A-III (A400) and 1.64 for classes A-IV (A600), A-V (A800) and A-VI (A 1000).

Quality control of indicators of mechanical properties of products at the manufacturing plant

2.1. The required quality indicators of profiles are ensured by compliance with production technology and controlled by testing in accordance with the requirements of clause 3.5, clauses. 4.4 - 4.8.

2.2. Quantities , , S And S 0 installed in accordance with test results and the provisions of Appendix 2.

Quality control of indicators of mechanical properties of products at the consumer enterprise

3.1. The consumer, if he has a quality document for products of the highest quality category, may not test the mechanical properties.

3.2. If it is necessary to check the mechanical properties of each batch, six samples taken from different bags or skeins and from different profiles are tested, and based on the results, the fulfillment of the conditions is checked

where is the average value of mechanical properties based on the test results of six samples;

X min is the minimum value of the test results of six samples.

3.3. The minimum values of relative elongation δ 5 and uniform elongation δ r must be no less than the values given in table. 8.

(Changed edition, Amendment No. 3).

APPENDIX 2
Mandatory

METHODOLOGY
determination of statistical indicators of strength characteristics of mechanical properties
hot-rolled steel for reinforcing reinforced concrete structures

This technique applies to hot-rolled, accelerated-cooled, thermomechanically and thermally strengthened rolled products of periodic profiles made in coils or rods.

The technique is used to assess the reliability of mechanical properties in each batch of smelting and steel as a whole, and to control the stability of the technological process.

To determine statistical indicators of mechanical properties (physical yield strength σ t or conditional σ 0.2, tensile strength σ v), control test results called general populations are used.
Compliance of the mechanical properties of rolled products with the requirements of regulatory and technical documentation is determined on the basis of statistical processing of test results forming a sample from the general population. All findings, results and conclusions drawn from the sample apply to the entire population.
A sample is a set of control test results that form an information array to be processed.

The sample includes the results of acceptance tests of rolled products of the same class, one grade and smelting method, rolled into one or a group of similar profile sizes.

Quantities S determined according to regulatory and technical documentation.

Minimum value S 0 equals 1.

Where Xi br - rejection value of σ t (σ 0.2) and σ in, specified in the relevant regulatory and technical documentation.

(Introduced additionally, Amendment No. 3).

INFORMATION DATA

DEVELOPED AND INTRODUCED by the Ministry of Ferrous Metallurgy of the USSR, Gosstroy of the USSR
APPROVED AND ENTERED INTO EFFECT by the Decree of the USSR State Committee for Standards dated December 17. No. 4800
INSTEAD GOST 5.1459-72, GOST 5781-75
REFERENCE REGULATIVE AND TECHNICAL DOCUMENTS

Designation of the ITD for which it is given link	Item number	Designation of the ITD referred to	Item number
GOST 380-94	2.3, 2.4	GOST 12348-78	4.1
GOST 2590-88	1.6	GOST 12350-78	4.1
GOST 7564-97	4.5	GOST 12352-81	4.1
GOST 7565-81	3.4	GOST 12355-78	4.1
GOST 7566-94	3.2, 3.6, 5.1	GOST 12356-81	4.1
GOST 9454-78	4.8	GOST 14019-2003	4.7
GOST 12004-81	4.6	GOST 18895-97	4.1
GOST 12344-2003	4.1	OST 14-34-78	Appendix 2

The validity period was lifted according to Protocol No. 3-93 of the Interstate Council for Standardization, Metrology and Certification (IUS 5-6-93)
EDITION (November 2005) with Amendments No. 1, 2, 3, 4, 5, approved in February 1984, June 1987, December 1987, October 1989, December 1990 (5-84, 11-87, 3-88, 1-90, 3-91).

Posted in Tagged ,

Hot-rolled steel for reinforcement of ferroconcrete structures. Specifications

GOST 5781-82

OKP 09 3004; 09 3005;

09 3006; 09 3007; 09 3008

Date of introduction 07/01/83

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of Ferrous Metallurgy of the USSR, State Construction Committee of the USSRDEVELOPERS

N.M.Vorontsov, Ph.D. sciences; I.S. Grin, Ph.D. sciences; K.F. Peretyatko;

G.I. Snimshchikova; A.G. Bolshova; E.D. Gavrilenko; Ph.D. sciences; K.V.Mikhailov, Doctor of Engineering. sciences; S.A.Madatyan, Ph.D. sciences; N.M. Mulin, Ph.D. sciences; V.Z.Meshkov, Ph.D. Sciences, B.P. Goryachev, Ph.D. sciences; B.N. Fridlyanov; V.I.Petina

2. APPROVED AND ENTERED INTO EFFECT by Resolution of the State Committee of the USSR on Standards dated December 17, 1982 No. 4800

3. INSTEAD GOST 5.1459-72, GOST 5781-75

4. REFERENCE REGULATIVE AND TECHNICAL DOCUMENTS

Designation of the referenced technical document	Item number
GOST 380-88	2.3, 2.4
GOST 2590-88	1.6
GOST 7564-73	4.5
GOST 7565-81	3.4
GOST 7566-81	3.2, 3.6, 5.1
GOST 9454-78	4.8
GOST 12004-81	4.6
GOST 12344-88	4.1
GOST 12348-78	4.1
GOST 12350-78	4.1
GOST 12352-81	4.1
GOST 12355-78	4.1
GOST 12356-81	4.1
GOST 14019-80	4.7
GOST 18895-81	4.1
OST 14-34-78	Appendix 2

5. The validity period was lifted by decision of the Interstate Council for Standardization, Metrology and Certification (Protocol 3-93 of 02/17/93)

6. REISSUE (December 1993) with Amendments No. 1, 2, 3, 4, 5, approved in February 1984, June 1987, December 1987, October 1989, December 1990 (5 -84, 11-87, 3-88,1-90, 3-91), as amended (IUS No. 2-3, 1994)

This standard applies to hot-rolled round steel of smooth and periodic profiles intended for the reinforcement of ordinary and prestressed reinforced concrete structures (reinforcing steel).

Regarding the standards for the chemical composition of low-alloy steels, the standard also applies to ingots, blooms and billets.

(Changed edition, Amendment No. 4).

1. Classification and assortment

1.1. Depending on the mechanical properties, reinforcing steel is divided into classes A-I (A240), A-II (A300), A-III (A400); A-IV (A600), A-V (A800), A-VI (A1000).

At the request of the consumer, steel of classes A-II (A300), A-III (A400), A-IV (A600) and A-V (A800) is made smooth.

1.1; 1.2. (Changed edition, Amendment No. 5).

1.4. The nominal diameters of periodic profiles must correspond to the nominal diameters of smooth profiles of equal cross-sectional area.

Table 1

1.5. The weight of 1 m of profile is calculated based on the nominal dimensions with a steel density of 7.85. 10 3 kg/m 3 . The probability of providing a mass of 1 m must be at least 0.9.

(Changed edition, Amendment No. 3).

1.6. The maximum deviations of the diameter of smooth profiles must comply with GOST 2590-88 for normal rolling accuracy.

1.7. Reinforcing steel of a periodic profile is a round profile with two longitudinal ribs and transverse protrusions running along a three-lead helical line. For profiles with a diameter of 6 mm, protrusions running along a single-lead helical line are allowed, with a diameter of 8 mm - along a double-start helical line.

1.8. Reinforcing steel of class A-II (A300), manufactured in a conventional design, with a profile shown in Fig. 1a, and special purpose Ac-II (Ac300) with the profile shown in drawing. 2a, must have protrusions running along helical lines with the same approach on both sides of the profile.

Steel class A-III (A400), manufactured with the profile shown in Fig. 1b, and classes A-IV (A600), A-V (A800), A-VI (A1000) with the profile shown in Fig. 1b, 2b, should have protrusions along helical lines that have right entries on one side of the profile and left entries on the other.

Reinforcing steel for special purposes of class Ac-II (Ac300) is made with profiles shown in Fig. 1a or 2a.

The profile shown in Fig. 2a, for special purposes is manufactured by agreement between the manufacturer and the consumer. The shape and dimensions of the profiles shown in Fig. 2a and b may be specified.

Crap. 1

Crap. 2

1.9. Dimensions and maximum deviations of dimensions of reinforcing steel of periodic profile, manufactured according to drawing. 1a and b must correspond to those given in table. 2, but damn. 2a and b - given in table. 3.

table 2

Dimensions, mm

Note. At the request of the consumer, maximum deviations of size d 1 should not exceed maximum deviations d plus double maximum deviations h.

Table 3

Dimensions, mm

1.10. Relative displacements of helical protrusions on the sides of the profile, separated by longitudinal ribs, are not standardized.

Dimensions for which maximum deviations are not established are given for caliber construction and are not checked on the finished profile.

1.11. The ovality of smooth profiles (the difference between the largest and smallest diameters in the water section) should not exceed the sum of the plus and minus maximum deviations in diameter.

1.9. - 1.11. (Changed edition. Amendment No. 3).

1.12. Reinforcing steel of classes A-I (A240) and A-II (A300) with a diameter of up to 12 mm and class A-III (A400) with a diameter of up to 10 mm inclusive is produced in coils or rods, large diameters - in rods. Reinforcing steel of classes MV (A600), A-V (A800) and A-VI (A1000) of all sizes is produced in rods, with a diameter of 6 and 8 mm, produced in coils by agreement between the manufacturer and the consumer.

1.13. The rods are made from 6 to 12 m long:

measured length;

measured length with unmeasured segments of at least 2 m in length, not more than 15% of the lot weight;

of unmeasured length.

In a batch of rods of unmeasured length, the presence of rods with a length of 3 to 6 m is allowed, no more than 7% of the mass of the batch.

By agreement between the manufacturer and the consumer, it is possible to manufacture rods from 5 to 25 m.

1.14. Maximum deviations along the length of measuring rods must correspond to those given in table. 4.

Table 4

High-precision rods are manufactured according to customer requirements.

1.15. The curvature of the rods should not exceed 0.6% of the measured length.

Examples of symbols.

Reinforcing steel with a diameter of 20 mm, class A-II (A300):

20-A-11 GOST 5781-82

Reinforcing steel with a diameter of 18 mm, class A-I (A240):

18-A-1 GOST 5781-82

In the designation of rods of class A-II (A300) for special purposes, the index c is added: Ac-II (Ac300).

(Changed edition, Amendment No. 4).

2. Technical requirements

2.1. Reinforcing steel is manufactured in accordance with the requirements of this standard and technological regulations approved in the prescribed manner.

2.2. Reinforcing steel is made from carbon and low-alloy steel of the grades indicated in table. 5. The steel grade is indicated by the consumer in the order. If there is no indication, the steel grade is determined by the manufacturer. For class A-IV (A600) rods, steel grades are installed by agreement between the manufacturer and the consumer.

Table 5

Notes:

It is allowed to manufacture reinforcing steel of class A^(A800) from steel grades 22Х2Г2АУ, 22Х2Г2Р, and 22Х2Г2СС.
The dimensions indicated in brackets are manufactured by agreement between the manufacturer and the consumer.

(Changed edition, Amendment No. 3, 4).

2.3. The chemical composition of reinforcing carbon steel must comply with GOST 38088, low-alloy steel - with the standards given in table. 6

Table 6

2.3.1. In steel grade 20ХГ2Ц, it is allowed to increase the mass fraction of chromium to 1.7% and replace zirconium with 0.02-0.08% titanium. In steel grade 23Х2Г2Т it is allowed to replace titanium with 0.050.10% zirconium. In this case, in the designation of steel grade 20KhG2Ts, instead of the letter C, the letter T is used; in steel grade 23Kh2G2T, the letter C is used instead of the letter T.

In steel grade 32G2Rps, aluminum can be replaced with titanium or zirconium in equal units.

2.3.2. The mass fraction of nitrogen in steel grade 22Х2Г2АУ should be 0.015-0.030%, the mass fraction of residual nitrogen in steel grade 10GT should be no more than 0.008%.

2.3.3. The mass fraction of boron in steel grades 22Kh2G2R, 20Kh2G2SR and 32G2Rps should be 0.0010.007%. In steel grade 22Х2Г2АУ, the addition of 0.001-0.008% boron is allowed.

2.3.4. It is allowed to add titanium to steel grades 18G2S, 25G2S, 35GS based on its mass fraction in finished rolled products of 0.01-0.03%, to steel grade 35GS based on its mass addition to finished rolled products produced in coils of 0.01-0.06 %.

2.4. Deviations in the chemical composition of finished rolled products made from carbon steels - according to GOST 380-88, from low-alloy steels subject to the standards of mechanical properties - Table. 7. Minus deviations in the content of elements (except for titanium and zirconium, and for the steel grade 20Kh2G2SR silicon) are not limited.

Table 7

Note. By agreement between the manufacturer and the consumer, steel can be manufactured with other deviations in the content of chromium, silicon and manganese.

(Changed edition, Amendment No. 3).

2.5. Reinforcing steel of classes A-I (A240), A-II (A300), A-III (A400), A-IV (A600) is made hot-rolled, class A-V (A800) - with low-temperature tempering, class A-VI ( A1000) - with low-temperature tempering or thermomechanical treatment in the flow of a rolling mill.

It is allowed not to carry out low-temperature tempering of steel of classes A-V (A800) and A-VI (A1000) provided that a relative elongation of at least 9% and a uniform elongation of at least 2% are obtained when tested within 12 hours after rolling.

2.6. The mechanical properties of reinforcing steel must comply with the standards specified in table. 8.

For class A-II (A300) steel with a diameter over 40 mm, a reduction in elongation of 0.25% is allowed for each millimeter increase in diameter, but not more than 3%.

For steel class Ac-II (Ac300), the tensile strength can be reduced to 426

MPa (43.5 kgf/mm 2) with a relative elongation δ 5 of 30% or more.

2.7. Statistical indicators of the mechanical properties of periodic profile reinforcing steel bars must comply with Appendix 1, with increased uniformity of mechanical properties - Appendix 1 and Table. 9.

The probability of achieving the mechanical properties indicated in table. 8, must be at least 0.95.

(Changed edition, Amendment No. 3).

Table 8

Notes:

By agreement between the manufacturer and the consumer, it is possible not to test the impact strength of class Ac-II reinforcing steel.
(Deleted, Amendment No. 3).
For reinforcing steel of class A-IV with a diameter of 18 mm, grade 80C steel, the cold bending rate is set to at least 30°.
For reinforcing steel of class A-I (A240) with a diameter of over 20 mm when bending in a cold state by 180° c = 2d, class A-II (A300) with a diameter of over 20 mm c = 4d.
Symbols of the class of reinforcing steel according to yield strength are indicated in brackets.

(Changed edition, Amendment No. 1, 3, 5).

2.8. On the surface of the profile, including the surface of the ribs and protrusions, there should be no rolled out cracks, stress cracks, flaws, rolling films or sunsets.

Minor damage to the ribs and protrusions is allowed, in the amount of no more than three per 1 m of length, as well as minor rust, individual rolled-out contamination, prints, sagging, traces of rolled-out bubbles, rippling and scaliness within the permissible deviations in size.

(Changed edition, Amendment No. 2).

2.9. The weldability of reinforcing steel of all grades, except 80C, is ensured by the chemical composition and manufacturing technology.

2.10. Carbon equivalent
for welded reinforcement bars

from low-alloy steel class A-III (A400) should be no more than 0.62.

(Introduced additionally, Amendment No. 5).

Table 9

Notes:

S - standard deviation in the general population of tests;
- So - standard deviation in the melting batch;
- x is the average value in the population of tests;
- ~ - minimum average value in a batch-smelting.
For reinforcing steel in coils with a diameter of 6 and 8 mm, it is allowed to increase the standards for S and S 0 by 4.9 MPa (0.5 kgf/mm 2).

3. (Deleted, Amendment No. 5).

3. Acceptance rules

3.1. Reinforcing steel is accepted in batches consisting of profiles of the same diameter, one class, one melt-ladle and issued with one quality document.

The batch weight should be up to 70 tons.

It is allowed to increase the mass of the batch to the mass of the melting ladle.

3.2. Each batch is accompanied by a quality document in accordance with GOST 7566-81 with additional data:

profile number; Class;

minimum average value x~ and standard deviations S 0 in a batch of values

σ T (σ 0.2) and σ B

results of cold bending tests;

values of uniform elongation for steel classes A-IV (A600), A-V (800), A-VI (A1000).

3.3. To check the size and quality of the surface, select:

in the manufacture of reinforcing steel in rods - at least 5% of the batch; when produced in skeins - two skeins from each batch.

(Changed edition, Amendment No. 3).

3.4. To check the chemical composition, samples are taken according to GOST 7565-81.

The manufacturer determines the mass fraction of aluminum periodically, but at least once a quarter.

3.5. To test for tensile, bending and impact strength, two rods are selected from the batch. For the manufacturer, the sampling interval of rods must be at least half

time spent on rolling one profile size of one batch.

(Changed edition, Amendment No. 3).

3.6. If unsatisfactory test results are obtained for at least one of the indicators, repeated tests are carried out in accordance with GOST 7566-81.

4. Test methods

4.1. Chemical analysis of steel is carried out according to GOST 12344-88, GOST 12348-78, GOST 12350-78, GOST 12352-81, GOST 12355-78, GOST 12356-81, GOST 18895-81 or other methods that ensure the required accuracy.

4.3. Dimensions are checked with a measuring tool of the required accuracy.

4.4. One sample is cut from each selected rod for tensile, bending and impact testing.

4.5. Sampling for testing tensile, bending and impact strength is carried out in accordance with GOST 7564-73.

4.6. The tensile test is carried out according to GOST 12004-81.

4.7. The bending test is carried out according to GOST 14019-80 on samples with a cross-section equal to the cross-section of the rod.

For rods with a diameter over 40 mm, it is allowed to test samples cut along the axis of the rod on a mandrel with a diameter reduced by half compared to that indicated in the table. 4, by applying a bending force from the side of the cut.

4.8. Determination of impact strength is carried out according to GOST 9454-78 on samples using a U type 3 concentrator for rods with a diameter of 12-14 mm and type 1 samples for rods with a diameter of 16 mm or more. Samples are manufactured in accordance with the requirements of GOST9454-78.

4.9. It is allowed to use statistical and non-destructive methods for monitoring the mechanical properties and weight of profiles.

4.10. The curvature of the rods is measured along the length of the supplied profile, but not shorter than 1 m.

4.11. Determination of statistical indicators of mechanical properties in accordance with mandatory Appendix 2.

4.12. The quality of the surface is checked without the use of magnifying devices.

4.10 - 4.12. (Introduced additionally, Amendment No. 3).

4.13. The height of the transverse projections of a periodic profile should be measured along the vertical axis of the cross-section of the reinforcing bars.

(Introduced additionally, Amendment No. 4).

5. Packaging, labeling, transportation and storage

5.1. Packaging, labeling, transportation and storage - in accordance with GOST 7566-81 with additions:

the ends of rods made of low-alloy steels of class A-IV (A600) must be painted with red paint, class A-V - red and green, class A-VI (A 1000) - red and blue. Painting of ties is allowed at a distance of 0.5 m from ends;

the rods are packaged in bundles weighing up to 15 tons, tied with wire or wire rod. At the consumer's request, the rods are packaged in bundles weighing up to 3 and 5 tons.

Paint is applied to skeins in strips no less than 20 mm wide across the turns on the outside of the skein.

For unpackaged products, paint is applied to the end or side surface at a distance of no more than 500 mm from the end.

On the label attached to each bundle of rods, the accepted designation of the reinforcing steel class (for example, A-III) or the symbol of the yield strength class (A400) is applied.

ANNEX 1

(Required)

Requirements for statistical indicators of mechanical properties

1. The manufacturer guarantees the consumer the average values of tensile strength σ B and yield strength (physical σ T and conditional σ 0.2) in general

totality - ~ and the minimum average values of these same indicators in each batch-smelting - x i ; the values of which are set from the conditions:

where x i br - rejection values of values σ B , σ 0.2 indicated in table. 8 of this standard;

t is the quantile value, taken equal to 2 for classes A-II and A-III and 1.64 for rods of classes A-IV, A-V and A-VI.

2. Quality control of indicators of mechanical properties of products at the manufacturer.

2.1. The required quality indicators of profiles are ensured by compliance with production technology and are controlled by testing in accordance with the requirements of clause 3.5, clauses. 4.4 - 4.8.

2.2. The values of xi, x, S and S 0 are established in accordance with the test results and the provisions of Appendix 2.

3. Quality control of indicators of mechanical properties of products at the consumer enterprise.

3.1. The consumer, if he has a quality document for products of the highest quality category, may not test the mechanical properties.

3.2. If it is necessary to check the mechanical properties of each batch, six samples taken from different bags or skeins and from different profiles are tested, and the fulfillment of the conditions is checked based on the results

where x 6 is the average value of mechanical properties based on the test results of six samples;

Xmin is the minimum value of the test results of six samples.

3.3. The minimum values of relative elongation δ 5 and uniform elongation δ p must be no less than the values given in table. 8.

(Changed edition, Amendment No. 3, 5).

APPENDIX 2 (Required)

Methodology for determining statistical indicators of the strength characteristics of the mechanical properties of hot-rolled products for reinforcing reinforced concrete structures

This technique applies to hot-rolled, accelerated-cooled, thermomechanically and thermally strengthened rolled products of periodic profiles made in coils or rods.

The technique is used to assess the reliability of mechanical properties in each batch of smelting and steel as a whole, and to control the stability of the technological process.

1. To determine statistical indicators of mechanical properties (physical yield strength δ T or conditional δ 0.2, tensile strength δ in) are used

reference test results, called populations.

2. Compliance of the mechanical properties of rolled products with the requirements of regulatory and technical documentation is determined on the basis of statistical processing of test results forming a sample from the general population. All findings, results and conclusions drawn from the sample apply to the entire population.

3. Sampling - a set of control test results that form an information array to be processed.

The sample includes the results of acceptance tests of rolled products of the same class, one grade and smelting method, rolled into one or a group of similar profile sizes.

4. The sample on the basis of which statistical indicators are calculated must be representative and cover a sufficiently long period of time, but not less than three months, during which technological process does not change. If necessary, the time period for sampling can be increased. Checking the homogeneity of the sample according to regulatory and technical documentation.

5. The number of heat batches in each sample must be at least 50.

6. When forming a sample, the condition of random sampling from the smelting batch must be observed. The assessment of abnormality of test results is carried out according to regulatory and technical documentation.

7. During statistical processing, the average value x, the standard deviation S of each sample (general population), the standard deviation within the heat batch S 0, as well as the standard deviation of the melts are determined

medium S 1. The value of S 1 is determined by the formula

The values of x and S are determined according to the regulatory and technical documentation.

8. The stability of characteristics x and S is checked in accordance with OST 14-34-78.

9. The value of S 0 is determined for accelerated-cooled, thermomechanically and thermally

for hardened reinforcing steel only by the experimental method, for hot-rolled steel - by the experimental method and the swing method according to the formula

where ω and S ω are, respectively, the average value and standard deviation of the range distribution for two tests from the batch. The minimum value of S0 is 1.

10. Determination of the value of S 0 by the experimental method is carried out at least for

two heats for each steel grade, class and profile size of rolled products by randomly selecting at least 100 samples from each heat.

11. The value of the minimum average value of strength characteristics (δT (δ0.2) and δв) in each batch x 2 is determined from the condition x 1 = x - t. S, where t is the quantile value of 1.64 for a probability of 0.95.

12. The minimum value of the results of tensile tests of two samples (n = 2) of each batch subjected to control must be at least x min, determined by the formula

13. To provide a guarantee to the consumer of mechanical properties, the following conditions must be satisfied:

where x i br is the rejection value of δ t (δ 0.2) and δ in, specified in the relevant regulatory and technical documentation.

(Introduced additionally, Amendment No. 3).

This standard applies to hot-rolled round reinforcing steel of smooth and periodic profiles intended for the reinforcement of ordinary and prestressed reinforced concrete structures.

Regarding the standards for the chemical composition of low-alloy steels, the standard also applies to ingots, blooms and billets.

Reinforcing steel of periodic profile
Construction reinforcement bars with transverse protrusions (corrugations) evenly spaced on their surface at an angle to the longitudinal axis of the bar to improve adhesion to concrete.
Reinforcing steel smooth
Round rods with a smooth, non-corrugated surface to improve adhesion to concrete.
Strength class
The standardized value of the physical or conditional yield strength of steel established by the standard.

Angle of inclination of transverse protrusions
The angle between the transverse projections (corrugation) and the longitudinal axis of the rod.
Transverse lug pitch
The distance between the centers of two successive transverse projections, measured parallel to the longitudinal axis of the rod.
Height of transverse projections
The distance from the highest point of the transverse protrusion to the surface of the core of a periodic profile rod, measured at right angles to the longitudinal axis of the rod.
Nominal diameter of periodic profile reinforcing steel (profile number)
The diameter of a round smooth rod of equal cross-sectional area.
Nominal cross-sectional area
A cross-sectional area equivalent to the cross-sectional area of a smooth round rod of the same nominal diameter.

GOST 10884-81

Thermo-mechanical and thermally strengthened steel rods of periodic profile with a diameter of 6-40 mm (construction reinforcement), are intended for the construction of critical reinforced concrete structures.
According to this standard construction fittings Depending on the mechanical properties, they are divided into classes: Ax-III, At-IV, At-V, At-VI, At-VII, At-VIII.
Reinforcement according to this standard is made from the following grades of steel:

Reinforcing steel class	steel grade
At-III	St5 (St5sp, St5ps)
AT-IV, AT-IVC, AT-IVK	20GS; 25G2S; 35GS; 28С;10ГС2; 08G2S; 25С2Р;
At-V (K and SK)	20GS; 20GS2; 08G2S; 10GS2; 28C; 25G2S; 35GS; 25С2Р; 20ХГС2;
At-VII	30ХС2;

GOST 5781-82

Depending on the mechanical properties, the reinforcement is divided into classes A-I (A240), A-II (A300), A-III (A400), A-IV (A600), A-V (A800), A-VI (A1000).
Construction reinforcement is made in rods or coils. Construction fittings class A-I (A240) is made smooth, classes A-II (A300), A-III (A400), A-IV (A600), A-V (A800), A-VI (A1000) - periodic profile. At the consumer's request, fittings of classes A-II (A300), A-III (A400), A-IV (A600), A-V (A800) are manufactured smooth.

Construction fittings periodic profile is a round profile with two longitudinal ribs and transverse protrusions running along a three-lead helical line. For profiles with a diameter of 6 mm, protrusions running along a single-start helical line are allowed, with a diameter of 8 mm - along a double-start helical line.

Construction fittings class A-II (A300), manufactured in a regular design, and special purpose Ac-II (Ac300), must have protrusions running along helical lines with the same approach on both sides of the profile.

Construction fittings class A-III (A400) and classes A-IV (A600), A-V (A800), A-VI (A1000) must have protrusions along helical lines that have right entries on one side of the profile and left entries on the other.

Relative displacements of helical projections on the sides of the profile, separated by longitudinal ribs, are not standardized.

Construction fittings classes A-I (A240) and A-II (A300) with a diameter of up to 12 mm and class A-III (A400) with a diameter of up to 10 mm inclusive are produced in coils or rods, large diameters - in rods. Construction fittings classes A-IV (A600), A-V(A800) and A-VI (A1000) of all sizes are manufactured in rods with a diameter of 6 and 8 mm - by agreement between the manufacturer and the consumer in coils.

Construction fittings made from carbon and low-alloy steel of the grades indicated in the table. For reinforcing bars of class A-IV (A600), steel grades are established by agreement between the manufacturer and the consumer.

Steel grades used for the manufacture of fittings of different classes (GOST 5781-82)

Reinforcing steel class	Profile diameter, mm	steel grade
A-I (A240)	6-40	St3kp, St3ps, St3sp
A-II (A300)	10-40 40-80	St5sp, St5ps 18G2S
Ac-II (Ac300)	10-32 (36-40)	10GT
A-III (A400)	6-40 6-22	35GS, 25G2S 32G2Rps
A-IV (A600)	10-18 (6-8) 10-32 (36-40)	80C 20ХГ2Ц
A-V (A800)	(6-8) 10-32 (36-40)	23Х2Г2Т
A-VI (A1000)	10-22	22Kh2G2AYu, 22Kh2G2R, 20Kh2G2SR

Notes:
It is allowed to manufacture fittings of class A-V (A800) from steel grades 22Х2Г2АУ, 22Х2Г2Р and 20Х2Г2СС. The dimensions of the fittings indicated in brackets are manufactured by agreement between the manufacturer and the consumer.

The West Siberian Metallurgical Plant produces thermomechanically strengthened construction fittings classes A400C and A500C according to TU 14-1-5254-94. The low carbon content, along with thermomechanical processing of the reinforcement in the rolled product stream, ensures its improved weldability and ductility, increased toughness and durability. This construction heat-strengthened reinforcement its properties meet the requirements of international standards.

The Gosstroy of Russia recommends the use of reinforcing steel A400S and A500S in reinforced concrete structures along with and instead of reinforcing steel of classes A-III grades 25G2S and 35GS (GOST 5781-82) and At-IIIS (GOST 10884-81) of the same diameters. Thermotechnical and thermally strengthened steel rods of periodic profile with a diameter of 6-40 mm are intended for the construction of critical reinforced concrete structures (GOST 10884-81).
Parameters of rod reinforcement (GOST 5781-82)

Profile number (nominal rod diameter), mm	Weight of 1 m profile, kg	Number of meters in 1 ton	Cross-sectional area, cm 2
6	0,222	4504,50	0,283
8	0,395	2531,65	0,503
10	0,617	1620,75	0,785
12	0,888	1126,13	1,131
14	1,210	826,45	1,540
16	1,580	632,91	2,010
18	2,000	500,00	2,540
20	2,470	404,86	3,140
22	2,980	335,57	3,800
25	3,850	259,74	4,910
28	4,830	207,04	6,160
32	6,310	158,48	8,040
36	7,990	125,16	10,180
40	9,870	101,32	12,570
45	12,480	80,13	15,000
50	15,410	64,89	19,630
55	18,650	53,62	23,760
60	22,190	45,07	28,270
70	30,210	33,10	38,480
80	39,460	25,34	50,270

Thermomechanically strengthened reinforcement for reinforced concrete structures. GOST 10884-94

Thermal fittings are divided into classes depending on:

on mechanical properties - the strength class of the reinforcement (established by the standard standardized value of the conditional or physical yield strength in newtons per square millimeter);
from operational characteristics - to welded reinforcement (index C), reinforcement resistant to corrosion cracking (index K).

The fittings are manufactured in classes At400S, At500S, At600, At600S, At600K, At800, At800K, At1000, At1000K and At1200. By agreement between the manufacturer and the consumer, reinforcement of strength class At800 and higher can be made smooth.

Marking:

In the absence of rolling markings, the ends of bars or bundles of reinforcement of the corresponding class must be painted with indelible paint of the following colors:

At400S fittings - white;
At500S fittings - white and blue;
At600 fittings - yellow;
At600S fittings - yellow and white;
At600K fittings - yellow and red;
At800 fittings - green;
At800K fittings - green and red;
At1000 fittings - blue;
At1000K fittings - blue and red;
At1200 fittings - black.

Reinforcing steel class	steel grade
At400S	St3sp, St3ps
At500S	St5sp, St5ps
At600	20GS
At600S	25G2S, 35GS, 28S, 27GS
At600K	10GS2, 08G2S, 25S2R
At800	20GS, 20GS2, 08G2S, 10GS2, 28S, 25G2S, 22S, 35GS, 25S2R, 20GS2
At800K	35GS, 25S2R
At1000	20GS, 20GS2, 25S2R
At1000K	20ХГС2
At1200	30ХС2

Steel rod and wire rod reinforcement belongs to the category long products. Reinforcement and wire rod are manufactured according to the technical specifications:

Based on the nature of the profile, the reinforcement is divided into smooth - class AI and corrugated (periodic profile for reinforcement) - classes AII, AIII, AIV, AV, AVI.

The range of reinforcement and wire rod corresponds to:

The chemical composition of steel grades used for the manufacture of reinforcement and wire rod corresponds to:

Fittings - depending on class:

AI fittings - St3kp(ps, sp);
Fittings AII - St5sp(ps), 18G2S;
Reinforcement AIII - 35GS, 25G2S, А500С, А400С, 32G2RPS.

GOST 5781-82

INTERSTATE STANDARD

HOT-ROLLED STEEL
FOR REINFORCEMENT
REINFORCED CONCRETE STRUCTURES

TECHNICAL CONDITIONS

Date of introduction 01.07.83

This standard applies to hot-rolled round steel of smooth and periodic profiles intended for the reinforcement of ordinary and prestressed reinforced concrete structures (reinforcing steel).

Regarding the standards for the chemical composition of low-alloy steels, the standard also applies to ingots, blooms and billets.

(Changed edition, Amendment No. 4).

1. CLASSIFICATION AND ASSORTMENT

1.1. Depending on the mechanical properties, reinforcing steel is divided into classes A-I (A240), A-II(A300), A-III (A400), A-IV (A600), A-V (A800), A-VI (A1000).

1.2. Reinforcing steel is manufactured in bars or coils. Reinforcing steel of class A-I (A240) is made smooth, classes A- II (A300), A-III (A400), A -IV (A600), A-V (A800) and A-VI (A1000) - periodic profile.

At the consumer's request, steel classes A-II(A300), A-III (A400), A-IV (A600) and A-V (A800) are made smooth.

1.1, 1.2. (Changed edition, Amendment No. 5).

Reinforcing steel for special purposes class Ac- II (Ac300) are made with profiles shown on or .

The profile shown on is manufactured for special purposes by agreement between the manufacturer and the consumer. The shape and dimensions of the profiles shown on, , may be specified.

1.9. Dimensions and maximum deviations in dimensions of reinforcing steel of periodic profile, manufactured according to, , must correspond to those given in , and according to , - given in .

Dimensions, mm

Profile number (nominal diameter d n)

Prev. off

Note: At the consumer's request, maximum size deviations d 1 should not exceed maximum deviations d plus double maximum deviations h.

The probability of achieving the mechanical properties specified in must be at least 0.95.

(Changed edition, Amendment No. 3).

2.8. On the surface of the profile, including the surface of the ribs and protrusions, there should be no rolled cracks, stress cracks, flaws, rolled films or sunsets.

(Changed edition, Amendment No. 2).

2.9. The weldability of reinforcing steel of all grades, except 80C, is ensured by the chemical composition and manufacturing technology.

2.10. Carbon equivalent for welded rod reinforcement made of low-alloy steel of class A-III (A400) should be no more than 0.62.

(Introduced additionally, Amendment No. 5).

The manufacturer determines the mass fraction of aluminum periodically, but at least once a quarter.

4. TEST METHODS

4.1 Chemical analysis of steel is carried out according to GOST 12344, GOST 12348, GOST 12350, GOST 12352, GOST 12355, GOST 12356, GOST 18895 or other methods that provide the required accuracy.

4.3. Dimensions are checked with a measuring tool of the required accuracy.

4.6. The tensile test is carried out according to GOST 12004.

4.7. The bending test is carried out according to GOST 14019 on samples with a cross-section equal to the cross-section of the rod.

For rods with a diameter over 40 mm, it is allowed to test samples cut along the axis of the rod on a mandrel with a diameter reduced by half compared to that specified in , with a bending force applied from the side of the cut.

4.8. Determination of impact strength is carried out according toGOST 9454on samples with a concentrator of the form U type 3 for rods with a diameter of 12 - 14 mm and type 1 samples for rods with a diameter of 16 mm and more. Samples are manufactured in accordance with the requirements of GOST 9454.

4.9. It is allowed to use statistical and non-destructive methods for monitoring the mechanical properties and mass of profiles.

4.10. The curvature of the rods is measured along the length of the supplied profile, but not shorter than 1 m.

4.11. Determination of statistical indicators of mechanical properties in accordance with mandatory.

4.12. The quality of the surface is checked without the use of magnifying devices.

4.10 - 4.12. (Introduced additionally, Amendment No. 3).

4.13. The height of the transverse projections of a periodic profile should be measured along the vertical axis of the cross-section of the reinforcing bars.

(Introduced additionally, Amendment No. 4).

5. PACKAGING, LABELING, TRANSPORTATION AND STORAGE

5.1. Packaging, labeling, transportation and storage - according to

Hot-rolled fittings for reinforcing reinforced concrete structures. Hot rolled steel for reinforcement of reinforced concrete structures Technical specifications GOST 5781 82

1. CLASSIFICATION AND ASSORTMENT

2. TECHNICAL REQUIREMENTS

3. ACCEPTANCE RULES

4. TEST METHODS

5. PACKAGING, LABELING, TRANSPORTATION AND STORAGE

ANNEX 1Mandatory

REQUIREMENTS FOR STATISTICAL INDICATORS OF MECHANICAL PROPERTIES

APPENDIX 2 Mandatory

INFORMATION DATA

1. Classification and assortment

2. Technical requirements

3. Acceptance rules

4. Test methods

5. Packaging, labeling, transportation and storage

ANNEX 1

(Required)

Requirements for statistical indicators of mechanical properties

APPENDIX 2

(Required)

Methodology for determining statistical indicators of the strength characteristics of the mechanical properties of hot-rolled products for reinforcing reinforced concrete structures

GOST 10884-81

GOST 5781-82

Thermomechanically strengthened reinforcement for reinforced concrete structures. GOST 10884-94

Marking:

1. CLASSIFICATION AND ASSORTMENT

4. TEST METHODS

5. PACKAGING, LABELING, TRANSPORTATION AND STORAGE

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ANNEX 1
Mandatory

APPENDIX 2
Mandatory