GOST 10884-94

• gost-10884-94.pdf (720.96 KiB)
  ГОСТ 10884-94

GOST 10884−94 case hardening steels thermomechanical reinforced for concrete structures. Specifications

GOST 10884−94
Group B22

INTERSTATE STANDARD

THERMOMECHANICALLY HARDENED STEEL BARS FOR REINFORCED CONCRETE STRUCTURES

Specifications

Thermomechanically hardened steel bars for reinforced concrete constructions. Specifications

ISS 77.140.70*
OKP 09 3100
09 3200
09 3300
09 3400

Date of introduction 1996−01−01

Preface

1 DEVELOPED by TC 120 «Cast iron, steel, rolled"

INTRODUCED by Gosstandart of Russia

2 ADOPTED by the Interstate Council for standardization, Metrology and certification (Protocol N 6 of October 17, 1994)

The standard was accepted by voting:

The name of the state	The name of the national authority for standardization
The Republic Of Azerbaijan	Azgosstandart
The Republic Of Armenia	Armastajad
The Republic Of Belarus	Gosstandart Of Belarus
The Republic Of Georgia	Gosstandart
The Republic Of Kazakhstan	Gosstandart Of The Republic Of Kazakhstan
The Kyrgyz Republic	Kyrgyzstandard
The Republic Of Moldova	Moldovastandart
Russian Federation	Gosstandart Of Russia
The Republic Of Uzbekistan	Standards
Ukraine	Gosstandart Of Ukraine

3 Resolution of the State Committee of the Russian Federation for standardization, Metrology and certification dated April 13, 1995 N 214 inter-state standard GOST 10884−94 introduced directly as state standard of the Russian Federation from January 1, 1996

4 REPLACE GOST 10884−81

5 REISSUE. September 2009

1 Scope

This standard applies to thermomechanically strengthened reinforcing steel smooth and periodic profile diameters 6−40 mm, intended for reinforcement of concrete structures.

The standard contains certification requirements for thermomechanically strengthened reinforcing steel for concrete structures.

2 Normative references

The present standard features references to the following standards:

GOST 380−2005 carbon Steel of ordinary quality. Brand

GOST 2999−75 Metals and alloys. Method of measurement of hardness by Vickers

GOST 5781−82 hot-rolled Steel for reinforcement of concrete structures. Specifications

GOST 7564−97 hire. General rules of sample, blanks collection for mechanical and technological tests

GOST 7565−81 (ISO 377−2-89) Iron, steel and alloys. Sampling method for determination of chemical composition

GOST 7566−94 metal Products. Acceptance, marking, packing, transportation and storage

GOST 10243−75 Steel. Test method and evaluation of the macrostructure

GOST 12004−81 Steel reinforcement. Test methods tensile

GOST 12344−2003 Steel alloyed and high alloy. Methods for determination of carbon

GOST 12345−2001 (ISO 671−82, ISO 4935−89) Steel alloyed and high alloy. Methods of determining sulphur

GOST 12346−78 (ISO 439−82, ISO 4829−1-86) Steel alloyed and high alloy. Methods for determination of silicon

GOST 12347−77 Steel alloyed and high alloy. Methods for determination of phosphorus

GOST 12348−78 (ISO 629−82) Steel alloyed and high alloy. Methods for determination of manganese

GOST 12350−78 Steel alloyed and high alloy. Methods for determination of chromium

GOST 12352−81 Steel alloyed and high alloy. Methods for determination of Nickel

GOST 12355−78 Steel alloyed and high alloy. Methods for determination of copper

GOST 12356−81 Steel alloyed and high alloy. Methods for determination of titanium

GOST 12357−84 Steel alloyed and high alloy. Methods for determination of aluminium

GOST 12358−2002 Steel alloyed and high alloy. Methods for determination of arsenic

GOST 12359−99 (ISO 4945−77) Steels carbon, alloyed and high alloy. Methods for determination of nitrogen

GOST 12360−82 Steel alloyed and vysokolikvidnye. Methods of boron determination

GOST 14019−2003 (ISO 7438−85) Materials metal. Method of bend test

GOST 14098−91 welded Joints of reinforcement and embedded products for reinforced concrete structures. Styles, design and sizes

GOST 18895−97 Steel. Method of photoelectric spectral analysis

3 Definitions

In this standard use the following terms with respective definitions:

3.1 Reinforcing steel periodic profile — bars with spaced on the surface at an angle to the longitudinal axis of the rod cross ledges (corrugation) to improve the adhesion with the concrete.

3.2 Reinforcing steel smooth round rods with a smooth surface having no corrugations to improve the adhesion with the concrete.

3.3 Class strength is established by the standard specified value of conditional or physical yield point of steel.

3.4 the Angle of inclination of transverse ridges — the angle between the lateral ribs (corrugations) and the longitudinal axis of the rod.

3.5 Step transverse ridges — the distance between the centres of two consecutive transverse ribs measured parallel to the longitudinal axis of the rod.

3.6 the height of the lateral ribs is the distance from the highest point of the transverse ledge to a surface of the core rod periodic profile, measured at right angles to the longitudinal axis of the rod.

3.7 nominal diameter of reinforcing steel periodic profile (the profile number) — diameter of equal-sized cross-sectional area of a round smooth bar (table 1).

3.8 nominal cross-sectional area — the cross-sectional area equivalent to the cross sectional area of round smooth stud of the same nominal diameter.

4 Basic parameters and dimensions

4.1 Reinforcing steel are divided into classes according to:

— mechanical properties — strength class (prescribed by the standard specified value of conditional or physical yield stress in Newtons per square millimeter);

— operational characteristics — caribaea (index), resistant against corrosion cracking (index To).

4.2 Reinforcement steel manufactures class At400c, At500c, At600, At600c, At600k, At800, At800k, At1000, At1200 and At1000k.

4.3 Reinforcement steel are made with a periodic profile according to figure 1 elegost 5781.

Figure 1

The dimensions of the periodic structure corresponding to figure 1 are given in table 1.

Table 1

In millimeters

The nominal diameter of the reinforcing steel (number, profile)	The parameters of the periodic profile									The size of the markings
	no less				*			no more
nomi- national	deviations in accuracy
ordinary Noah	increase increased
6	5,8	0,4	7,0	+0,8	±0,6	5	0,6	1,0	1,9	0,4	2	3	-
8	7,7	0,6	9,3	A 1.0	6	0,8	1,25	2,5	0,6	4
10	9,5	0,8	11,5	+0,9 1.6 million	7	1,0	1,5	3,1	0,8	3
12	11,3	1,0	13,7	8	1,2	2,0	3,8	1,0
14	13,3	1,1	15,9	9	1,4	4,4	1,1
16	15,2	1,2	18,0	+1,2 -1,8	±0,8	10	1,6	5,0	1,2	5
18	17,1	1,3	20,1	Eleven	1,8	5,6	1,3	4
20	19,1	1,4	22,3	12	2,0	6,3	1,4
22	21,1	1,5	24,5	14	2,2	6,9	1,5
25	24,1	1,6	27,7	15	2,5	7,9	1,6
28	27,0	1,8	31,0	+1,7 -2,5	±1,2	17	2,8	2,5	8,8	1,8
32	30,7	2,0	35,1	18	3,2	3,0	10,0	2,0	6
36	34,5	2,3	39,5	19	3,6	11,3	2,3
40	38,4	2,5	43,8	20	4,0	12,5	2,5
* Maximum deviations are ±15%.

In coordination with the consumer the reinforcing steel of strength class At800 and above are allowed to produce smooth.

4.4 Reinforcing steel with a profile corresponding to figure 1, is a circular shaft with two longitudinal ribs or without them, and arranged at an angle to the longitudinal axis of the rod transverse Crescent-shaped lugs in the middle, not intersecting with the longitudinal edges and running along multistart helix with the sides of the profile different direction.

4.4.1 the angle between the cross ribs and the longitudinal axis of the rod it is recommended to take equal to 45°.

Allowed the angle you make from 35 to 70°.

4.4.2 the Angle of inclination of the side faces of the transverse processes should be 30 to 45°.

4.4.3 the distance between the endings of the transverse processes should not exceed the values given in table 1.

4.4.4 For reinforcing steel diameters 6, 8 and 10 mm allowed a pair of longitudinal ribs with the lateral ribs of equal height at a ratio of 0.075.

Values and permissible deviations of the size match is given in table 1 for the size .

The roundness of the rods (the difference between and in one section) shall not exceed the sum of the positive and negative extreme deviations in size .

4.4.5 the Dimensions, which does not have limit deviations are given for construction of caliber, and ready for rentals don’t control them.

4.5 the Nominal diameters of the reinforcing steel cross sectional area, linear density (the mass of rod of length 1 m), maximum deviations in sizes and weight, roundness and curvature of the rods must comply with table 1 and GOST 5781.

Note — the nominal diameter of reinforcing steel periodic profile (the profile number) corresponds to the nominal diameter of equal-sized cross-sectional area of smooth reinforcing steel.

4.6 Reinforcing steel with a diameter of 10 mm and more are made in the form of rods with length specified in the order.

Reinforcing steel diameters 6 and 8 mm are made in rolls. Manufacturer of reinforcing steel At400c, At500c class and At600c with a diameter of 10 mm is allowed in reels.

4.6.1 Rods are made of standard length from 5.3 to 13.5 m. it is possible to produce rods measuring up to a length of 26 m.

The length of the rods — at the request of the consumer.

4.6.2 Caribaea reinforcing steel is allowed to deliver in the form of rods:

— measuring length with non-standard segments with a length of at least 2 m in an amount of not more than 15% of the batch weight;

— random lengths from 6 to 12 m. In the party such reinforcing steel is allowed in bars with length from 3 to 6 m in an amount of not more than 7% of the batch weight.

4.7 maximum deviations along the length of the rods lengths must comply with the requirements of GOST 5781.

4.8 Marking of reinforcing steel should include:

— nominal diameter (profile) mm;

— the designation of the strength class (4.1);

— designation of its operational characteristics — weldability (index), resistance against stress corrosion cracking (index To).

Examples of symbols

Reinforcing steel with a diameter of 20 mm, strength class At800:

20Ат800 GOST 10884−94

The same 10 mm diameter, strength class Ат400 welded (C):

10Ат400С GOST 10884−94

The same, 16 mm diameter, strength class At600, resistant against corrosion cracking (K):

16Ат600К GOST 10884−94

5 Technical requirements

5.1 Reinforcing steel manufactured in accordance with the requirements of this standard for technological regulations approved in the prescribed manner.

5.2 Reinforcing steel is made from carbon and low-alloy steel with a mass fraction of chemical elements on the screener test are shown in table 2.


Table 2

Grade of reinforcing steel	Mass fraction of chemical elements, %
carbon, not more than	manganese	silicon	sulfur	phosphorus
no more
At400c	0,24	0,5−1,5	Not more than 0.65	0,045	0,045
At500c	0,32
At600c, At600k, At800, At800k, At1000, At1000k	0,6−2,3	0,6−2,4
At1200	0,6−1,0	1,5−2,3
Notes 1 For reinforcing steel, class At400c and At500c, while ensuring the mechanical properties and weldability allowed mass fraction of silicon up to 1.2%. 2, For reinforcing steel of class At500c allowed mass fraction of carbon less than 0.37%. 3 Recommended steel grades and their chemical composition is given in Appendix A.

5.3 For welding reinforcing steel, class At400c carbon equivalent defined by the formula , must be at least 0.32 percent, At500c class — not less than 0.40%, class At600c is not less than 0,44%.

In the formulae, MP and Si is the mass fraction of the corresponding chemical elements.

5.4 tolerances for chemical composition in a ready rolled from the norms established by table 2, shall be as given in table 3.


Table 3

Chemical element	Pred. off %
Carbon	+0,02
Manganese	+0,10
Silicon	±0,10
Sulfur	+0,005
Phosphorus	+0,005

5.5 Weldability and resistance to corrosion cracking is provided by reinforcing steel chemical composition and manufacturing technology in accordance with Annex B.

5.6 Mechanical properties of reinforcing steel before and after the electric heating, as well as the test results of her bending shall conform to the requirements of table 4.


Table 4

Mechanical properties
The strength class of fittings- Noah steel	Nomi- national diameter, mm	Tempe temperatures of the electro- heating, °C	Temporary support tavlenie rupture , N/mm	Conditional or physical yield strength , N/mm	Take tional elongation, %		The bend test in cold state	The mandrel diameter (nominal diameter)
not less than
Ат400	6−40	-	550	440	16	-	90°	3
Ат500	600	500	14
At600	10−40	400	800	600	12	4	45°	5
At800	10−32*	1000	800	8	2
At1000	10−32	450	1250	1000	7
At1200	1450	1200	6
* For reinforcing steel of class At800k diameters 18−32 mm. Notes 1, For reinforcing steel of class At600c allowed the temporary reduction of tear resistance of 50 N/mmbelow the norms established by the table, when the increase of the relative elongation of 2% (abs.) and uniform elongation of 1% (abs.). 2 For reinforcement steel At400c, At500c class and At600c in rods rupture strength shall not exceed the values given in the table, more than 200 N/mm. 3, For reinforcing steel of strength class At1200 in the state of delivery may reduce the conditional yield strength up to 1150 N/mm. 4, When testing the reinforcing steel strength classes At800, At1000 At1200 and immediately after rolling may reduce the ductility of 1% (abs.).

Statistical parameters of mechanical properties of reinforcing steel must conform to table 5 and Annex B.


Table 5

The nominal diameter of the reinforcing steel (number, profile), mm	Statistical parameters of mechanical properties
Standard deviation, N/mm				Attitude
10−14	90	90	50	50	0,09	0,08	0,06	0,05
SV. 14	80	80	45	45	0,08	0,07	0,05	0,04
Notes: 1  — the standard deviation of the parameter in the General set of tests;  — the standard deviation of the parameter of the party;  — the average value of the parameter in the General set of tests;  — the minimum average value of the parameter in the party. 2 For reinforcement steel class At400c and At500c diameters 6−10 mm, in rolls of value and accept in accordance with GOST 5781, for reinforcing steel of class A-III.

5.7 At the request of the consumer reglamentary requirements for stress relaxation, fatigue strength and test of bending and straightening.

5.7.1 For reinforcing steel strength classes At800, At1000 At1200 and stress relaxation should not exceed 4% per 1000 hours at an initial stress of 70% of maximum effort corresponding to the temporary tear resistance according to table 4.

Norms are not looking to 01.01.97.

5.7.2 Reinforcing steel strength classes At800, At1000 At1200 and must withstand without failure 2 million cycles of voltage at 70% nominal tensile strength tensile. The voltage interval for smooth reinforcing steel shall be 245 N/mm, for reinforcing steel of periodic profile — 195 N/mm.

Norms are not looking to 01.01.97.

5.7.3 For reinforcing steel At400c, At500c class and At600c the bend test may be replaced by a test of bending and straightening in accordance with Annex G.

After the test none of the test samples should not have ruptures or cracks visible to the naked eye.

5.8 For reinforcing steel strength classes At800, At1000 At1200 and apparent yield stress shall be not less than 0.85 .

5.9 the quality of the surface of reinforcing steel shall conform to the requirements of GOST 5781.

5.10 the Marking during rolling

5.10.1 Reinforcing steel periodic profile is marked with strength class and manufacturer’s inflicted on her rolling in the form of marking short transverse ribs or dots on the transverse protrusions, in accordance with Annex D.

5.10.2 Marking short transverse rib height of 0.5 mm that does not extend beyond the overall size of the circle diameter , is placed on the surfaces adjacent to longitudinal edges (figures 1a, b).

5.10.3 Marking the points with a height equal to the height of a lateral rib, are cone-shaped thickenings on the transverse protrusions (figure 1b).

The base diameter of the cone-shaped thickening is shown in table 1.

5.10.4 strength Grade of reinforcing steel designated by the number of lateral ribs according to table 6 in the interval in figure 1.


Table 6

Strength grade of reinforcing steel	The number of transverse protrusions in the interval
Ат400	3
Ат500	1
At600	4
At800	5
At1000	6
At1200	7

5.11 in the absence of rolling marking the ends of the rods or bundles of reinforcing steel of the appropriate class should be painted with indelible paint in the following colors:

At400c white;

At500c — white and blue;

At600 — yellow;

At600c yellow and white;

At600k yellow and red;

At800 — green;

At800k green and red;

At1000 — blue;

At1000k — blue and red;

At1200 — black.

Allowed coloration of ligaments at a distance of 0.5 m from the ends.

5.12 the Rods are Packed in bundles weighing up to 10 t, tied with wire. At the request of customers, the rods are Packed in bundles weighing up to 3 tons

5.13 When supplied in coils each coil should consist of one segment of reinforcing steel. Weight of coil — up to 3 t

A coil should be evenly bandaged around the circumference of no less than four places. Each of these matings must have intermediate tie (mating), which is based on the average thickness of the strand.

5.14 each ball or bundle of bars shall be securely attached a label, which indicate:

— trademark or a trademark and the name of the manufacturer;

— designation of reinforcing steel (4.8);

— the batch number;

— stamp of technical control.

5.15 in case of discrepancy of mechanical properties of reinforcing steel the markings of when it is rolling, the actual strength must be specified on the label and in the document of quality, and the ends of rods shall be painted in accordance with 5.11.

6 acceptance Rules

6.1 Reinforcing steel accept parties.

The party should consist of reinforcing steel of the same class and of the same diameter, made of a single melting-ladle.

The mass of the party — according to GOST 5781.

6.2 For the control of geometrical parameters of reinforcing steel and its linear density (mass of a rod of length 1 m) from the party taken:

— upon delivery in the rods not less than 5% of the party;

— when shipped in rolls — two rolls.

6.3 To check the chemical composition of the steel selected one sample from the bottoms of the bucket.

Sampling — according to GOST 7565.

6.4 For the control of mechanical properties of reinforcing steel from the party selected for the tensile tests before and after the electric heating in the two samples.

For bend test of the party selected the two samples.

6.5 the Control of the temporary rupture strength and conventional yield strength after the electrical heating is carried out in the absence of the process of special leave or leave with heating below the temperature specified in table 4.

6.6 To control stress relaxation, fatigue strength and bending and straightening (if regulation of these parameters at the request of the consumer) from the party selected for the tests:

— for stress relaxation and bending and straightening — four of the sample;

— on the fatigue strength of the six samples.

6.7 Sampling for the control of mechanical properties and tests of bending and stress relaxation, fatigue strength and bending and straightening is carried out according to GOST 7564.

The interval of sampling should be at least half the time spent on rolling reinforcing steel of the party.

6.8 Definition of statistical indicators of the strength characteristics of reinforcing steel in accordance with Annex B.

6.9 Control of mechanical properties may be performed by nondestructive methods in accordance with the normative-technological documentation.

6.10 If unsatisfactory test results of at least one of the indicators, repeat tests should be carried out according to GOST 7566.

6.11 Party reinforcing steel must be accompanied by a document of quality according to GOST 7566 with additional data:

— nominal diameter (profile) mm;

class of reinforcing steel;

mechanical properties before and after the electric heating;

— the minimum average value and standard deviation of temporary values of tear resistance and yield strength in the party;

— results of flexure tests in cold condition;

values of uniform elongation.

In the regulations at the request of the consumer stress relaxation, fatigue strength and bending and straightening (5.7) in the document about the quality of the result results of testing of these characteristics.

At the customer’s request must be specified the chemical composition of the steel.

7 control Methods

7.1 Geometric parameters of the reinforcement steel of check of the measuring tool necessary accuracy.

7.1.1 the Diameter and the roundness of the reinforcing steel is defined as the arithmetic mean value of three measurements on the section length of 1 m.

7.1.2 the height of the protrusions is determined as the arithmetic mean value of the measurements in the middle of two neighboring projections of each row of the slab with an accuracy of 0.01 mm.

7.1.3 Step lateral ribs and the distance between the endings of the transverse processes (figure 1) is defined as the arithmetic mean value of three measurements of each slab with an accuracy of 0.1 mm.

7.1.4 the Dimensions measured at a distance of not less than 150 mm from the end of the rod or at least 3000 mm from the end of the strand.

7.2 Linear density of reinforcement steel is defined as the arithmetic mean value of mass of two samples of 1 m length, weighed to the nearest 0.01 kg. the length of the sample is measured with an accuracy of 0.001 m.

7.3 Chemical composition of steel is determined according to GOST 12344−12348 GOST, GOST 12350, 12352 GOST, GOST 12355, 12356 GOST-GOST 12360, GOST 18895, or some other method, is not inferior in the measurement accuracy requirements of these standards.

The differences in the evaluation of the chemical composition of steel should be determined established by these standards methods.

7.4 tensile Test according to GOST 12004.

For determining mechanical properties should be applied to the nominal cross-sectional area of reinforcing steel.

7.5 Technique of heating the samples for controlling the temporary rupture strength and conventional yield strength after heating is established by agreement between manufacturer and consumer.

Allowed the use of furnace heating at temperatures 50 °C lower than indicated in table 4 and the exposure of the samples after heating them for 15 min.

7.6. Test cold bending — according to GOST 14019 on samples with cross-section equal to the cross-section check the profile.

7.7 Test stress relaxation, fatigue strength and bending and straightening is carried out according to normative-technical documentation.

8 Transportation and storage

Transportation and storage — by GOST 7566.

Annex a (recommended). Recommended steel grades

APPENDIX A
(recommended)

A. 1 Recommended grades of carbon and low-alloy steel for the manufacture of reinforcing steel, the corresponding classes are given in table A. 1.

Table A. 1

Grade of reinforcing steel	Designation according to previous NTD	Nominal diameter, mm	Steel grade
At400c	-	6−40	St3sp, St3ps
At500c	St5sp, St5ps
At600	At-IV	10−40	20ГС
At600c	At-lVC	25G2S, 35GS, 28C, 27ГС
At600k	At-IVK	10GS2, 08G2S, 25S2R
At800	At-V	10−32	20ГС, 20GS2, 08G2S, 10GS2, 28C, 25G2S, 22S
18−32	35GS, 25S2R, 20GS2
At800k	At-VK	35GS, 25S2R
At1000	At-Vl	10−32	20ГС, 20GS2, 25S2R
At1000k	At-VIK	20KHGS2
At1200	At-VII	30KHS2

A. 2 Chemical composition of carbon steel according to GOST 380, low — according to the norms given in table A. 2, grades 25G2S and 35GS — according to GOST 5781 with additional requirements under item A. 3.

Table A. 2

Steel grade	Mass fraction of chemical elements, %
carbon	manganese	silicon	chrome	sulfur	phosphorus	Nickel	copper
no more
08G2S	0,05−0,15	1,5−2,3	0,7−1,0	0,30	0,025	0,030	0,30	0,30
10GS2	0,08−0,14	1.0 to 1.5	1,6−2,1	0,045	0,045
20ГС	0,17−0,22	1.0 to 1.5	0,040	0,040
20GS2	1,7−2,4
20KHGS2	0,80−1,20
25S2R	0,20−0,29	0,5−0,9	1,2−1,7	0,30	0,045	0,045
28S	0,25−0,32	0,6−0,9	0,9−1,2	-	0,040	-
30KHS2	0,26−0,32	1,6−2,2	0,60−0,90	0,040	-
27ГС	0,24−0,30	0,9−1,3	1.0 to 1.5	0,30	0,045	0,045	0,30	0,30
22S	0,17−0,25	0,6−0,9	0,9−1,2	-	0,035	0,040	-	-
Notes 1 steel grade 08G2S, intended for the manufacture of reinforcing steel class At600k, the mass fraction of silicon has to be 0.6% to 1.2%. 2 For steel manufactures reinforcing steel of classes At600, At600c, At600k, At800 and At800k allowed the increase of the mass fraction of sulfur and phosphorus up to 0,045% each. 3 For the steel grade 25S2R mass fraction of boron should be 0,001−0,005%, titanium — 0,01−0,03%. 4, For reinforcing steel of all grades mass fraction of arsenic should be not more than 0.08%. 5 For 22S steel grade mass fraction of titanium should be not more than 0.05%, aluminum not more than 0.10%.

A. 3 steel grade 35GS, intended for the manufacture of reinforcement steel classes At600c, At800 and At800k, the mass fraction of carbon should be 0,28−0,33%, and the mass fraction of manganese 0,9−1,2%.

A. 4 maximum deviations in chemical composition in the ready-rolled carbon steel according to GOST 380, of low carbon steel in table A. 3.


Table A. 3

Chemical element	Pred. off %
Carbon	+0,02
Manganese	+0,10
Silicon	±0,10
Chrome	+0,05
Sulfur	+0,005
Phosphorus
Nickel	+0,05
Copper
Note — For reinforcing steel strength classes At600, At800 and At1000 (except steel grade 35GS) in the observance of mechanical properties and resistance to intercrystalline corrosion cracking negative deviations in chemical composition (except for silicon) are not a sign of rejection.

A. 5 Reinforcing steel of classes At800k, made of steel grade 35GS must have on the surface of a released layer of a thickness less than 0.3 mm and a hardness not exceeding 280 HV.

A. 5.1 released Control of the thickness of the layer and its hardness is carried out on two samples taken from the party.

The selection of templates to control the thickness and hardness of the surface of the released layer is carried out according to GOST 10243.

A. 5.2 determination of the thickness and hardness of the surface of the released layer is carried out on the etched Templeton (layer thickness is controlled by the minimum depth in the basin between lateral ribs of the profile). Hardness — GOST 2999.

A. 6 Reinforcing steel of classes At800 and Ат800С, made of steel grade 35GS, shall be subjected to 100% NDT on the length of the rods according to the temporary tear resistance (table 4 of this standard).

APPENDIX B (mandatory). Requirements for resistance against corrosion cracking, and weldability of reinforcing steel

APPENDIX B
(required)

B. 1 Resistance to corrosion cracking and the weldability of reinforcing steel provided by its chemical composition in accordance with the requirements of 5.2−5.4 of this standard, the level of its mechanical properties according to table 4 of this standard and production technology, established by the technological regulations.

B. 2 For reinforcing steel that is resistant against stress corrosion cracking after testing in nitrate solution consisting of 600 parts by weight of nitrogen calcium, 50 parts by weight of ammonium nitrate and 350 parts by mass of water at a temperature of 98−100 °C and at a voltage equal to 0,9(taken from table 4 of this standard), the time to failure from stress corrosion cracking shall be not less than 100 h

B. 3 For welded thermomechanically strengthened reinforcing steel of welded joints, the type, designs and sizes to meet the requirements of GOST 14098 must have a rupture strength not less than 0.9, as specified in table 4 of this standard.

ANNEX b (mandatory). Requirements for statistical indicators of the strength characteristics

THE APP
(required)

V. 1 the manufacturer guarantees the consumer the average values of the strength characteristics of reinforcing steel (temporary tear resistance and conditional or physical yield limit before and after electrical heating) in the General population and minimum average values of these characteristics in every batch-melting based on the following conditions:

;

;

,

where  — rejection values of the strength characteristics established by table 4 of this standard;

 — the standard deviation of the parameters in the General set of tests;

 — the standard deviation of the parameter in the party.

B. 2 Required quality indicators of reinforcing steel are provided with observance of technology of production of reinforcing steel with its mass production and controlled in accordance with the requirements of section 3 of this standard.

B. 3 values of , , and is determined on the basis of test results in accordance with the provisions of Annex E.

Q. 4 If you want to check consumer the strength characteristics of reinforcing steel prior to and after the electric heating to the temperatures specified in table 4 of this standard, and in cases of disagreement in assessing the quality of reinforcing steel from each batch are testing six samples taken from different bundles (coils) and rods, and the results of these tests verifies compliance to the respective characteristics of conditions:

where is the minimum value of the test parameter from the test results of six samples;

 — minimum average value of the test parameter for this batch;

 — the standard deviation check the parameter in the batch-melting;

the average value of the test parameter on the test results of six samples;

 — inspecting the value of the test parameter set by table 4 of this standard.

Values and  — according to the document about the quality of this batch of reinforcing steel.

APPENDIX d (reference). Test requirements for bending and straightening

APPENDIX D
(reference)

The bend test with the subsequent straightening is plastic deformation of the sample of reinforcement steel rod by bending to achieve a given angle in the heating and cooling curve of the sample under specified conditions and subsequent straightening (backward bending) under the action of force in the direction opposite to the original.

The axis of the two supports during bending and subsequent straightening should remain in the plane perpendicular to the direction of the force.

The test shall be conducted on universal testing machines or presses equipped with devices for bending and straightening. Diagrams of devices shown in the figures G. 1 and G. 2.

Figure G. 1

Figure 2

The test shall be conducted at a speed not exceeding 20 ° /s so that in the zone of tension were the transverse edges of the sample from a rod of reinforcing steel.

The distance between supports should not change during the test and should be

,

where is the mandrel diameter (table G. 1).

Table G. 1

In millimeters

The diameter of the mandrel and with nominal diameter of reinforcing steel
6	8	10	12	16	20	25	32	40
32	40	50	63	100	160	200	320	400

The angle of bend before heating (ageing) shall be 90°.

The bent sample was subjected to aging by heating to 100 °C with exposure at this temperature for at least 30 min and then cooled in air to a temperature of from 10 °to 35 ° C.

After cooling, the sample is carried out a test of straightening to straightening angle of 20° (figure 3).

1 — initial state; 2 — position after bending; 3 — position after straightening

Figure 3

Both angle measurements are taken before releasing the load.

The test sample, reinforcing steel, class At400c and At500c bent around the mandrel, the diameter of which is given in table G. 1.

The mandrel diameter for reinforcing steel with a diameter of 14, 18 and 28 mm as well as for reinforcing steel strength classes At600, At800, At1000 At1200 and must be agreed by the manufacturer and consumer.

The sample is considered to have withstood the test if no cracks visible without using the magnifying means.

APPENDIX e (mandatory). The structure of the marking of reinforcing steel periodic profile is applied when rolling

APPENDIX E
(required)

The structure of the marking of reinforcing steel periodic profile is applied when rolling

D. 1 Marking of reinforcing steel periodic profile is applied when it is rolling in the form of marking short transverse ribs or dots on the transverse ridges of the profile has the following structure:

— a sign of the beginning of the marking;

— the designation of the manufacturer;

— the designation of the strength class of the reinforcement steel.

1.1 Sign marking the beginning of the outline in the form of two short transverse markings of the ribs adjacent to the opposite longitudinal edges, or two masking points on the adjacent lateral protrusions of the profile.

1.2, the sign of the beginning of the marking indicates the manufacturer number of lateral ribs in the interval between marks in the form of short transverse ribs located at the longitudinal edges or points on the lateral protrusions of the profile (see figure D. 1).

Note — Refer to specific manufacturers are provided in the normative-technical documentation.

1.3 Marking of the strength class of the reinforcement steel in accordance with the present 5.10.4 standard feature for designation of the manufacturer.

D. 2 Examples of markings for reinforcing steel is shown in figure D. 1.

Figure D. 1


Marking

a) in the form of marking points on the lateral protrusions of the profile — manufacturer of Cherepovets steel mill (=3), reinforcing steel of strength class At600 (=4);

b) marking in the form of short transverse ribs are the manufacturer of sulinskiy steel works (=3), reinforcing steel of strength class At800 (=5).

ANNEX E (mandatory). The method of determining the statistical indicators of the strength characteristics of reinforcing steel

ANNEX E
(required)

E. 1 the Present methodology establishes a procedure for the application of statistical control methods to analyze and control the quality level of the reinforcing steel, made in the form of individual bars or in coils if it mass production and is used in assessing the reliability of its strength characteristics and reinforcing steel as a whole, and also for stability control of technological process in the production of reinforcing steel.

E. 2 For definition of statistical parameters established by the standard of the strength characteristics of reinforcing steel (temporary tear resistance and conditional or physical yield limit before and after electrical heating) use the results of the control tests, called a population.

Compliance with the strength characteristics of reinforcing steel requirements are determined on the basis of statistical processing of test results of reinforcing steel, forming the sampling control tests of concrete setting and strength characteristics of the reinforcing steel.

The conclusions made on the basis of sampling, refers to the entire General population.

E. 3 the Sample on the basis of which is carried out to determine the statistical indicators should be representative and cover a sufficiently long period of time (not less than 3 months), during which the technological process of production of the reinforcing steel were not changed.

The number of parties-heats in each sample should be at least 50.

E. 4 In the sample must enter the results of the control testing of reinforcing steel of one class, laminated on single or group of close sizes of sections of one grade of steel with one method of its smelting.

E. 5 the sample selection must ensure random selection of samples from each batch.

An assessment of the anomalous test results and the test of homogeneity of the sample is carried out according to normative-technical documentation.

E. 6 the aggregation of the results of control tests determine the average value of the specific parameter of the strength characteristics of reinforcing steel in the sample (the General population) is , the standard deviation of this parameter in this sample — and the standard deviation in his party-melting — and also the standard deviation plenochnykh medium — .

Value and is determined by normative-technical documentation.

The value determined by the experimental method not less than two bottoms for each steel grade, the same grade and diameter of reinforcing steel by random selection of at least 100 samples from each heat.

The value is determined by the formula

E. 7 Verification of stability characteristics and is carried out in accordance with OST 14−34.

E. 8 the Minimum average value of the specific parameter of the strength characteristics of reinforcing steel (, or ) to each batch-melting is determined by the formula

The minimum value of test results of two samples (=2) in each lot under inspection shall be not less than determined by the formula

where  — the average value of the specific parameter of the strength characteristics of reinforcing steel in the sample (the General population);

and  — features to be determined in E. 6.

E. 9 To guarantee the consumer a set standard of strength characteristics of reinforcing steel with a probability of 0.95 should be satisfied the following conditions:

where  — the average value of check the parameter of the strength characteristics of reinforcing steel in the sample (the General population);

 — inspecting the value of this parameter, set by table 4 of this standard;

 — the standard deviation check the parameter of the sample;

 — minimum average value of the test parameter in this game (E. 8);

 — the standard deviation check the parameter in the party.