GOST ISO 7800-2013

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  ГОСТ ISO 7800-2013

GOST ISO 7800−2013 Materials metal. Wire. Test a simple twist

GOST ISO 7800−2013

INTERSTATE STANDARD

Materials metal

Wire

Test a simple twist

Metallic materials. Wire. Simple torsion test

OKS 77.040.10

Date of introduction 2015−01−01

Preface

Goals, basic principles and main procedure of works on interstate standardization have been established in GOST 1.0−92 «interstate standardization system. Basic provisions» and GOST 1.2−2009 «interstate standardization system. Interstate standards, rules and recommendations on interstate standardization. The procedure of development, adoption, application, renewal and cancellation"
Data on standard

1 PREPARED by Federal state unitary enterprise «all-Russian research center for standardization information and certification of raw materials and substances» (FSUE «UNICEPS»)

2 as AMENDED by the Federal Agency for technical regulation and Metrology

3 ACCEPTED by the Interstate Council for standardization, Metrology and certification (Protocol No. 44−2013 dated 14 November 2013)

The standard was accepted by voting:

This standard is identical to international standard ISO 7800:2003* Metallic materials. Wire. Simple torsion test (the metal Materials. Wire. Test a simple twisting).

The international standard was developed by Subcommittee ISO TC 164/SC 2 «Ductility testing» of the technical standardization Committee ISO TC 164 «Mechanical testing of metals» of the International organization for standardization (ISO).

Translation from English (en).

Official copies of the international standard on the basis of which prepared this international standard, and international standards referenced, are available at the FSUE «STANDARTINFORM».

4 by Order of the Federal Agency for technical regulation and Metrology, dated 22 November* 1963 N-St interstate standard GOST ISO 7800−2013 introduced as a national standard of the Russian Federation from January 01, 2015

___________________

* Probably, the error of the original. Should read: by Order of the Federal Agency for technical regulation and Metrology dated November 22, 2013 N 1963-article — note the manufacturer’s database.

5 INTRODUCED FOR THE FIRST TIME

Information about the changes to this standard is published in the annual reference index «National standards», and the text changes and amendments — in monthly information index «National standards». In case of revision (replacement) or cancellation of this standard a notification will be published in the monthly information index «National standards». Relevant information, notification and lyrics are also posted in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet

1 Scope

This standard specifies the method of determining the ability of metallic wire, having a diameter or characteristic size of from 0.1 to 10 mm, inclusive, to withstand plastic deformation during simple torsion in one direction.

2 Symbols and designations

Characters and symbols used when testing a simple twisting of the wire is shown in figure 1 and listed in table 1.

Figure 1 — Symbols and designations used in the test is a simple twisting of wire

Marking

1 — clip

Figure 1

Table 1 — symbols and designations

3 Principle

The test involves twisting a sample of the wire around its axis in the same direction.

4 testing Equipment

4.1 Clips, minimum hardness 55 HRC, with parallel jaws. The recommended types of clamps are given in Appendix A.

4.2 testing Machineis designed not to prevent change of the distance between the clamping jaws, caused by compression of the sample during testing, and to subject the sample it was possible to apply some stretching force (see 7.1).

Jaws must be installed on the testing machine so that when tested, they remained aligned and were not used for application of bending force to the subject sample. Should be provided with the possibility of rotation of one of the jaws around the axis of the test sample, while the other clamping sponge should not be subjected to angular offset, if this offset is not necessary to measure bending moment.

The distance between the clamping jaws should be adjusted for specimens of different lengths.

5 Sample for test

5.1 the length of wire used as the sample for testing should be straightforward.

5.2 If you want to change, it must be performed by an appropriate method. The recommended method is given in Appendix V.

The surface of the wire must not be damaged in the process of editing, and the specimen shall not be subjected to torsion.

Wire with localized strong curvature should not be used for the test.

Unless stated otherwise, the nominal free distance between the clamping jaws must match the values specified in table.2.

Table 2 — the Dependence of the nominal free distance between the clamping jaws of the nominal diameter or characteristic dimension of wire

6 test Conditions

Basically the test is performed at a temperature of from 10°to 35 ° C. Tests carried out under controlled conditions, where required, should be carried out at a temperature of (23±5)°C.

7 Method

7.1 the Sample mounted on the testing machine (4.2) so that its longitudinal axis coincides with the axis of the jaws (4.1), and that during the test, it remained straightforward. Unless specified otherwise, this result can be obtained by application to the sample constant tensile stress not exceeding 2% of the nominal tensile strength tensile test sample.

7.2 After mounting the sample on the machine rotating one of the jaws with a constant permissible speed until the specimen will not break down or until a certain number of turns . Count the number of full revolutions transmitted to the sample rotating clamping jaw.

Note — To check the speed on the surface should hold the color line.

7.3 If the relevant standard for the product is not otherwise specified, the test speed specified wire diameters of steel, copper and copper alloys, aluminum and aluminum alloys should not exceed the values given in table.3.

Note — as a test of a simple twisting is insulated, to avoid excessive rise in temperature of the test sample. The temperature should not be higher than 60 °C.

7.4 If the number of turns , meets the standard, it is considered that the test sample has passed the test regardless of the place of rupture. If the number of the achieved turnovers , is not consistent with the requirements of the standard, and the gap is at a distance of 2or 2from jaws, it is considered that the test sample failed the test and should be repeated.

7.5 If you want to describe the gap when tested in torsion, it should be done on the basis of Annex C.

Note — wire with smaller diameter or characteristic dimension, it is possible to make no distinction between the classes according to the application (eg. 2b compared to 3b).

Table 3 — test speed

8 test report

The test report shall contain at least the following information:

a) reference to this international standard, eg., ISO 7800;

b) identification of the test sample (material, casting room, etc.);

c) the diameter or characteristic size , of the test sample;

d) details of the preparation of the test sample (method changes, etc.);

e) test conditions (eg. the free distance between the clamping jaws, the application tensile forces);

f) the number of turns.

Note — the test report may include an assessment of the gap.

Annex a (informative). Recommended types of clip depending on the size of the diameter, d, or characteristic dimension, D, of wire

Appendix A
(reference)

Recommended types of clip depending on the size of the diameter, or characteristic dimension, a , of wire

Table A. 1 — Recommended types of clip

Annex b (informative). The recommended method of straightening the twisted wire when you install it in a vise

The App
(reference)

Below is a method of straightening wire to install it in the clamps of the testing machine torsion. This technique is available for thick high-strength wire, which can be dangerous for the operator when trying to install it in the clamps for the test without primary protection wire.

Equipment includes: mounted bench vise, two adjustable jaws and a piece of wooden plate with a width of 45 mm and a thickness of 20 mm, the length of which is slightly smaller than the free distance between the clamping jaws, indicated in the 2nd column of the table.2 of this international standard. Size 20 mm may have a gradually decreasing cross-section from the center to each edge of the wooden plate so that the edges its thickness is equal to approximately 15 mm.

Set firmly in a wooden stove (45 mm) between the jaws and clamp it. Wrap protective material (such as adhesive tape for masking) around each clamping sponge that he was in contact with the wire when it is pressed to the plate. The masking tape will protect the wire from damage (rupture). Place the wire (curvature down) on top of the plate so that the wire the same distance beyond the edge of the plate. Adjust the jaws and set the wrapped sponge on top of the wire around one edge of the plate. Clamp the other end of the wire and bend it down along the plate. Squeeze the wire together on the other adjusted with a sponge, which ensures contact of the sponge wrapped with the wire. Insert the ends of the wire in the jaws, apply the tensile stress not exceeding 2% of the nominal limit of the tensile strength, pushing the jaws and remove the plate.

You can make a duplicate setup so that if necessary I had another wire for testing.

Application (reference). Evaluation of damage arising in the process of testing a simple twist

Application
(reference)

The electronic text of the document
prepared by JSC «Code» and checked by:
the official publication of the
M.: STANDARTINFORM, 2014