GOST 12766.4-90

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  ГОСТ 12766.4-90

GOST 12766.4−90 graded rolled steel of precision alloys of high electric resistance. Specifications (with Change No. 1)

GOST 12766.4−90
Group В32

INTERSTATE STANDARD

GRADED ROLLED STEEL OF PRECISION ALLOYS OF HIGH ELECTRIC RESISTANCE

Specifications

Graded rolled steel of precision alloys of high electric resistance. Specifications

OKP 09 6600*
______________
* See notes of FGUP «STANDARTINFORM».

Date of introduction 1991−01−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of metallurgy of the USSR

DEVELOPERS

V. I. Matorin, V. V. Sosnin, And V. T. Ababkov, L. L. Zhukov, A. A. Rivkin, M. E. Sopova, M. A. Zinoviev

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on management of quality and standards from 12.02.90 N 187

The change in N 1 taken by the Interstate Council for standardization, Metrology and certification (Protocol № 7 from 26.04.95)

Was the Technical Secretariat of MGS N 1616

The adoption voted:

3. REPLACE GOST 12766.4−77

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. Limitation of actions taken by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (ICS 11−12−94)

6. The re-release (December 1998) with amendment No. 1, approved in February 1996 (IMS 5−96)

The re-release (as of November 2008)
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* See notes of FGUP «STANDARTINFORM».


This standard applies to hot-rolled steel bars of circular cross-section of precision alloys with high electrical resistance, designed for the manufacture of heating elements and outlet connections.

1. TECHNICAL REQUIREMENTS

1.1. Long products must be manufactured in accordance with the requirements of this standard.

1.1.1. Long products classification:

— delivery:

Hanks — circle;

bars — round (bar);

— the variation of electric resistance of 1 m of rental:

usual quality — 1;

high quality PC;

— standardized indicators:

bars and rods of alloy with a normalized tenacity — A;

bars and rods, of alloy without normalized survivability.

1.2. Basic parameters and dimensions

1.2.1. Depending on the brand of alloy limits rolled sections shall be as given in table.1.

Table 1

1.2.2. Bars in size, shape and limit deviations should correspond to GOST 2590* normal accuracy of rolling.
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* On the territory of the Russian Federation the document is not valid. Standards 2590−2006. — Note the manufacturer’s database.

On agreement between the consumer and the manufacturer is allowed to produce long products in size, shape and limit deviations in accordance with GOST 22411.

Examples of symbols:

Rolled steel, in coils, with a diameter of 10 mm ordinary quality of grade H15N60-H:

The range 10−1-H15N60-H GOST 12766.4−90

Same rods, 10 mm in diameter of high quality, with a normalized tenacity of alloy grade KH23JU5T:

Circle (bar) 10-PK-A-KH23JU5T GOST 12766.4−90

1.3. Features

1.3.1. The chemical composition of the alloys H15YU5, KHN20JUS, KH23JU5, KH23JU5T, KH27JU5T, KHN70JU-N, H15N60-H, CR20NI80-H should correspond to GOST 10994.

1.3.2. Rolled steel in coils are made in soft annealed condition; in bars without heat treatment. Is permitted to manufacture bars in annealed condition. By agreement between manufacturer and user is allowed to produce long products with etched surface.

1.3.3. Electrical resistance of 1 m long steel in the soft state must conform to the standards given in table.2.

Table 2

(Changed edition, Rev. N 1).

1.3.4. The variation of electrical resistance of 1 m within a coil should not exceed 6%.

1.3.5. The persistence of the alloys tested according to the method G, for rolled steel in coils should conform to the standards given in table.3.

Table 3

(Changed edition, Rev. N 1).

1.3.6. (Deleted, Rev. N 1).

1.3.7. The surface of rolled products shall be free from cracks, flaws. Permitted defects such as scratches, fingerprints and individual small prisoner and sunsets with a depth not exceeding half of the total limit deviation for diameter.

By agreement between manufacturer and consumer requirements to the surface quality should match the samples, agreed in the prescribed manner.

1.3.8. Elongation of long-rolled steel in coils should conform to the standards given in table.5.

Table 5*

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* Table.4. (Deleted, Rev. N 1).

1.3.9. The weight of one coil of rolled products should conform to the standards given in table.6.

Table 6

The party allowed Hanks to the reduced mass of not more than 15% (by weight).

By agreement between manufacturer and consumer produce bags of different mass.

1.3.10. Correction factors for calculating changes in electrical resistance depending on temperature, the estimated service life is given in annexes 1 and 2; physical and mechanical properties of alloys, the maximum operating temperature are given in appendices 4−6 GOST 12766.1.

1.4. Marking

1.4.1. Labeling — according GOST 7566.

1.5. Packaging

1.5.1. Packaging according to GOST 7566 with additions.

1.5.1.1. Long products must be in rolls or bundles of skeins or rods. Skein must consist of one segment.

1.5.1.2. The outer diameter of a coil should be no more than 1200 mm, internal — not less than 180 mm.

1.5.1.3. Weight of cargo must not exceed when mechanized loading and unloading in open vehicles 5000 kg, indoor — 1250 kg.

2. ACCEPTANCE

2.1. Long products take parties. The party must consist of one metal bottoms, same size and must be issued a document about quality that contains:

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

— the symbol of long products;

— the weight of the batch;

— test results*;

— chemical composition of the alloy.
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* Document the quality in the line «results of tests of the survivability of» record «factory guarantee».


(Changed edition, Rev. N 1).

2.2. To check the quality of rolled products from the party taken:

— to determine the chemical composition of one sample from the melt;

— to determine the size, surface quality, weight 100% product;

— to determine the variation of electrical resistance of 1 m within a coil, an electric resistance of 1 m, relative elongation three coils (of wire). If there are more than three coils (bars) from each coil (bar) select three of the sample;

— to determine the survivability of a single sample of weight, enough to make at least 5 m wire with a diameter of 0.8 m.

2.3. Control of the variation of electrical resistance of 1 m within the same roll, the manufacturer conducts periodic, but not less than once per year.

2.4. The chemical composition of the alloys is certified by a document of quality issued by the company, smelting the metal.

2.5. The tenacity of alloys is certified according to a quality document issued by the company, izgotovlyayuschei wire, according to test results of other heats of the same cycle of melting.

Allowed to the manufacturer of rolled steel to ensure the survivability of the stability of manufacturing technology.

(Changed edition, Rev. N 1).

2.6. If unsatisfactory test results of at least one indicator of a re-test is carried out according to GOST 7566.

3. CONTROL METHODS

3.1. Sampling for chemical analysis is carried out according to GOST 7565.

Chemical composition of alloys determined according to GOST 28473, GOST 12344−12348 GOST, GOST 12350, 12352 GOST, GOST 12356, 12357 GOST, GOST 12364, 12365 GOST or other methods providing the required accuracy of the analysis.

(Changed edition, Rev. N 1)

3.2. The diameter and shape of the rolled section check caliper according to GOST 166, micrometer according to GOST 6507 or staples according to GOST 2216 in two mutually perpendicular directions of the same cross-section in at least three places.

The length of the rods check metal ruler according to GOST 427 or measuring tape according to GOST 7502.

3.3. The surface quality is checked visually. If necessary, the depth of the defect determine the micrometer depth gauge according to GOST 7470 or other tool, to ensure the necessary accuracy, or Stripping prior to the removal of the defect.

The location of the defect cleaned with sandpaper or a file with further comparative dimension to the stripped and unstripped areas.

3.4. Electrical resistance of long products is determined according to GOST 7229 with the use of instruments of accuracy class not worse than 0,05.

3.5. Mass of a coil is determined on the scales, ensuring the necessary measurement accuracy.

3.6. To determine the variation of electrical resistance within the coil to measure the electric resistance at the beginning and end of the strand and the difference between them relates to the arithmetic mean of the obtained values.

3.7. The tenacity of alloys is determined according to GOST 2419 method G, until it fails.

(Changed edition, Rev. N 1).

3.8. Elongation is determined according to GOST 10446 on samples with an estimated length of 100 mm.

3.9. For each type of testing shall be one sample from each selected coil or bar.

4. TRANSPORTATION AND STORAGE

4.1. Transportation and storage GOST 7566 with additions.

4.1.1. Storage conditions of long products up to 1 month — 3ЖЗ according to GOST 15150, for more than 1 months — 1L according to GOST 15150.

4.1.2. When transporting long products produced consolidation packages in accordance with GOST 24597.

The uld (link in links) according to GOST 7566.

(Changed edition, Rev. N 1).

5. MANUFACTURER’S WARRANTY

The manufacturer guarantees product compliance with the requirements of this standard while complying with the storage conditions. A storage warranty period — three years from the date of manufacture for rolled alloys grades KHN20JUS, H15N60-H, CR20NI80-H, KHN70JU-N two years from the date of manufacture for grades H15YU5, KH23JU5, KH23JU5T, KH27JU5T.

ANNEX 1 (reference). Correction factors for calculating changes in electrical resistance depending on temperature

ANNEX 1
Reference

Table 7

ANNEX 2 (informative). The estimated lifespan of long products made of alloys with high electric resistance when working as a heater

ANNEX 2
Reference

Table 8

NOTES OF FGUP «STANDARTINFORM»

1 On the first page to Supplement code: ISS 77.140.50 (index «National standards», 2008).

2 Information data. Reference normative and technical documents:

GOST 7502−89 replaced by GOST 7502−98;

GOST 12344−88 replaced by GOST 12344−2003;

GOST 12345−88 replaced by GOST 12345−2001 (ISO 671−82, ISO 4935−89)