GOST 1579-93

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  ГОСТ 1579-93

GOST 1579−93 (ISO 7801−84) Wire. Test method for bend

GOST 1579−93
(ISO 7801−84)

Group В79

INTERSTATE STANDARD
WIRE
Test method for bend
Wire. Bend test method

ISS 77.040.10
77.140.65
AXTU 1209

Date of introduction 1997−01−01

Preface

1 DEVELOPED by the Technical Committee 146 «Hardware"

INTRODUCED by Gosstandart of Russia

2 ADOPTED by the Interstate Council for standardization, Metrology and certification (Protocol No. 4 dated October 21, 1993)

The adoption voted:

3 this standard was developed by the direct application of international standard ISO 7801−84 „metal Materials. Wire. Test method for bend“ with additional requirements that reflect the needs of the economy

4 Decree of the Russian Federation Committee on standardization, Metrology and certification dated March 26, 1996 N 206 inter-state standard GOST 1579−93 introduced directly as state standard of the Russian Federation from January 1, 1997

5 REPLACE GOST 1579−80

6 REISSUE. December 2005

1 Scope

This standard establishes requirements for the method of determining the ability of wire of metals and alloys of different cross-sectional shape with a diameter or characteristic size of from 0.3 to 10,0 mm inclusive to undergo plastic deformation at the bends.

A specific range of diameters of the wire subjected to tests contained in the standards or normative-technical documentation on the wire.

Additional requirements that reflect the needs of the economy, in italics.

1A Normative references

In this standard, reference the following standard:

GOST 2789−73 surface Roughness. Parameters and characteristics

2 the essence of the method

The test is repeated bend up to 90 degrees from the rest position to one or the other side of the specimen, fixed at one end to the terminals of the device, via a cylindrical roller of a given radius.

3 Denote parameters, dimensions and definitions

The designation of parameters is shown in figure 1, indicate dimensions and definitions are shown in table 1.

1 — tested sample; 2 — the bending arm; 3 — lead and 4 — axis of rotation of the bending arm; 5 — cylindrical rollers; 6 — jaws; 7 — Vice; 8 — the nearest point of contact with the test sample

Table 1

4 testing Equipment

4.1 General requirements

The test machine shall be designed to comply with the parameters shown in figure 1 and the dimensions given in table 2.


Table 2

mm

4.2 Cylindrical rollers and jaws

4.2.1 Cylindrical rollers and jaws should have a hardness sufficient to provide rigidity and resistance to abrasive wear (at least 62 ). The roughness parameter of the working surface of rollers and sponges should not be more than 1.25 µm according toGOST 2789.

4.2.2 the radius of the cylindrical roller and limit deviations of actual values from the nominal shall be as given in table 2.

4.2.3 Cylindrical rollers and jaws is mounted so that the axis of the sample was placed in the same plane with the axis of rotation of the bending arm. The axis of the cylindrical rollers should be perpendicular to the plane of the bend, parallel to each other and must be in the same plane.

4.2.4 Clamping jaws should protrude a little over the surface of the cylindrical rollers at a distance of not more than 0.1 mm measured as the gap between the test sample and each of the cylindrical rollers on the line connecting the centers of their circles.

4.2.5 the Top edge of the jaws must be below the centers of the cylindrical rollers is 1.5 mm for cylinders with a radius to 2.5 mm, inclusive, to 3.0 mm for cylinders with a large radius (if 2.5 mm; =1.5 mm; > 2.5 mm; a =3.0 mm).

Allowed distance from the top edge of the jaws to the centers of the cylindrical rollers: 1.5 mm for cylinders with a radius of up to 1.75 mm inclusive and 0.5 for cylinders with a large radius.

4.3 Bending arm and leash

4.3.1 the distance from the upper generatrix of the cylindrical surface of the rollers to the axis of rotation of the lever should be (1,0±0,2) mm.

4.3.2 the Angle of deflection of the lever from the starting position to the right and left should be (90±3)°.

4.3.3 Holes in the leash needs to be extended at each end and have a diameter shown in table 2.

5 test sample

5.1 the length of wire used as the test sample, should be fairly straight, with slight curvature in the plane in which the bends will be made during the test.

5.2 If necessary, edit the sample, it should be carried out manually or, failing that, on the surface of wood, plastic material or copper using a hammer from the same material.

5.3 When you edit the surface of the wire must not be damaged, the sample should not be twisted, the cross section should not be changed.

5.4 separate the Wire from sharp bends should not be edit anduse as test sample.

6 test Method

6.1 Tests should be conducted under ambient temperature from 10 °C to 35 °C. the Arbitration testing is carried out at a temperature of (23±5) °C.

6.2 the radius of the roller , the distance , the diameter of the hole of the leash selected depending on the diameter of the wire in accordance with the requirements of table 2.

6.3 the test specimen is inserted in a vertical position of the bending lever in one of the holes of the leashas shown in figure 1. The lower end of the test sample is secured between clamping jaws so that the test sample was perpendicular to the axes of the cylindrical rollers. The length of the clamped end of the specimen shall not be less than the height of the jaws.

6.4 turning of the sample, and the longitudinal movement of its jaws when the test is not allowed.

6.5 Samples of wire shaped cross-section (rectangular, testoobraznogo, insoorance, wedge-shaped, trapezoidal profile) should be located so that the large size was parallel or almost parallel to the clamping jaws, as pokazanova figure 2.

Figure 2

For other profile shapes wire clamping method must be specified in the normative-technical documentation on the wire.

6.6 test sample bend through 90° alternately in opposite directions. The first bend is the bend of the free end of the test sample 90° and returning it to its original position. The following inflection is carried out in the opposite direction, as shown in figure 3. The test should not be interrupted between successive bends.

 — the typical size of shaped wire

Figure 3

6.7 the Bends should be performed with uniform speed, not exceeding one bend per second. Speed, inflection if necessary, can be reduced to allocated during the test the heat does not affect the test results.

6.8 To ensure that during testing, the permanent contact between the test sample and the cylindrical rollers to the sample can be attached to one of the types ofpre — tension. This can be a tensile stress value of not more than 2% of the nominal breaking strength or other value set in the standards or normative-technical documentation on the wire.

6.9 Test is carried out to the specified number of excesses or to the appearance of cracks, visible to the naked eye, or to the complete destruction of the sample in accordance with the requirements of specific standards or normative-technical documentation on the wire.

6.10 In the test devices without the counting device or counting device, locking extreme position of the lever, the score is performed as follows:

the first bend is the bend of the sample to the right or left by 90°;

second — bend the sample by 180° in the opposite direction;

third — bend 180° in the direction opposite to the previous bend, etc.

6.11 Gib, during which the failure occurs the test sample should not be counted in the number of bends .

7 test report

The test report shall contain:

a) designation of this standard;

b) characteristics of the test sample (steel grade, number of melt, etc.);

in) nominal diameter or minimum thickness of the test sample ;

d) data about the preparation of the sample to test (e.g., edit);

d) test conditions (for example the radius of the cylindrical bar, made if tensile stress);

e) criterion for ending the test;

g) test results.

Allowed in the test protocols for specific types of wire instead of the conditions and results of tests (subparagraphs d, e, f) state: «meets the NTD».