GOST 21937-76

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  ГОСТ 21937-76

GOST 21937−76 hot rolled Bulb steel for shipbuilding. Assortment (with Amendments No. 1, 2, 3)

GOST 21937−76
Group B22

INTERSTATE STANDARD
HOT ROLLED BULB STEEL FOR SHIPBUILDING
Assortment
Hot-rolled steel Unsymmetrical bulb section for chipbuilding. Dimensions

ISS 77.140.50
OKP 09 3100, 5100 09

Date of introduction 1978−01−01

The decision of the State standards Committee of the USSR Council of Ministers dated 18 June 1976 N 1474 date of introduction is established 01.01.78

Limitation of actions taken by Protocol No. 2−92 of the Interstate Council for standardization, Metrology and certification (ICS 2−93)

REPLACE GOST 5353−52 in part paleobiology steel profiles

EDITION (October 2012) with Changes No. 1, 2, 3, approved in June 1979, June 1987, June 1990 (IUS 7−79, 11−87, 10−90)

This standard applies to hot-rolled steel unsymmetrical bulb for shipbuilding.

(Changed edition, Rev. N 2, 3).

1. ASSORTMENT

1.1. Cross section single-ended bulbs must match that specified on the drawing.

1.2. The size of the bulb, the cross-sectional area, mass 1 m, reference values should correspond to those in table.1.

Table 1

Notes

1. The room is composed of steel bulb size in inches.

2. Weight of 1 m calculated with nominal sizes when the density of steel is equal to 7.85 g/cm.

3. When calculating the area and thickness of the attached belt is adopted equal to half the area and thickness of steel bulb.

4. The radii of curvature indicated in the drawing, this to build the caliber and prosobonia not check.

5. (Deleted, Rev. N 2).

1.2. Accuracy rolling bulbs produce:

high accuracy,

conventional precision — V.

(Added, Rev. N 2).

1.3. Maximum rejections of sizes of steel bulb shall be as specified in table.2.

Table 2

mm

(Changed edition, Rev. N 2).

1.4. Maximum deviations from the theoretical masses of the party must not exceed plus 3 or minus 5%.

1.4.1. (Deleted, Rev. N 2).

1.4.2. Bulbs in all rooms can be made with only plus or only minus marginal deviations in altitude or extreme deviations in weight.

1.5. Blunting of the corners of the bottom of an end wall shall not exceed 0.3 times the wall thickness. The value is provided by the technology of production and on the finished prosobonia not checked.

1.4.2, 1.5. (Changed edition, Rev. N 2).

1.6. The change in the gradient of the shelf is allowed within ±2°. The value is provided by the technology of production and on the finished prosobonia not controlled.

1.7. Any crooked areas of the outer edge of the shelf relative to the plane of the wall should take the height of the bulb for maximum deviations.

1.8. Bulbs are manufactured with the length from 4 to 20 m:

the measured length;

multiple of gauging length;

random length

from 4 to 10 m — bulbs N 5−6,

from 4 to 12 m — to N 7−12 bulbs,

from 4 to 20 m — N to bulbs 14−24;

limited length within off-gage.

(Changed edition, Rev. N 2).

1.8.1. Length of steel bulb specified in the order.

1.8.2, 1.9. (Deleted, Rev. N 2).

1.10. Maximum deviations along the length of the bulb measured length or a multiple of measuring should not exceed:

+40 mm when the length of the bulb up to 8 m;

+60 mm — with a length of steel bulb from 8 to 12 m;

+80 mm — with a length of steel bulb over 12 m.

At the request of the consumer tolerances for length shall be +5 mm for every 1 m of length, but not more than +80 mm with a length of steel bulb more than 8 m.

1.11. The wrinkling of the ends should not withdraw bulb for the limit deviations in length.

1.10, 1.11. (Changed edition, Rev. N 2).

1.12. The curvature of bulbs in the planes of the walls and shelves of class I shall not exceed 0,3% of the measured length, class II — 0.6% of the measured length.

For bulbs N 8 and 10, class I manufactured without heat hardening, the curvature should not exceed 0.25% of the measured length.

(Changed edition, Rev. N 2, 3).

1.12.1. (Deleted, Rev. N 2).

1.13. Control the size, the curvature of bulbs in the planes of the walls and shelves is carried out at a minimum distance of 500 mm from the ends of the bulbs.

(Changed edition, Rev. N 3).

Sections 2−5. (Deleted, Rev. N 3).