GOST 25172-82

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  ГОСТ 25172-82

GOST 25172−82 (ISO 3878−83) sintered hard Alloys. Method for determination of hardness by Vickers (with Amendments No. 1, 2)

GOST 25172−82
(ISO 3878−83)

Group B59

STATE STANDARD OF THE USSR

SINTERED HARD ALLOYS

Method for determination of hardness by Vickers

Sintered hardmetals. Method of determination of Vickers hardness

AXTU 1909

Date of introduction 1983−01−01

INFORMATION DATA

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

DEVELOPERS

V. I. Tumanov, A. A. Zaluzhny, N. N. Gerasko, L. S. Pavlova

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 17.03.82 N 1097

Change No. 2 adopted by the Interstate Council for standardization, Metrology and certification (Protocol No. 6 dated 21.10.94)

The adoption voted:

3. INTRODUCED FOR THE FIRST TIME

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. Limitation of actions taken on the Protocol, the Interstate Council for standardization, Metrology and certification (ICS 2−93)

6. REPRINT (January 1998) with Amendments No. 1, 2, approved in may 1987, March 1995 (IUS 8−87, 5−95)


This standard specifies a method for determining the Vickers hardness of sintered hard alloys.

Allowed to conduct the hardness test according to ISO 3878−83 given in Appendix 2.

(Changed edition, Rev. N 2).

1. SAMPLING METHOD

1.1. Sampling is carried out according to GOST 20559.

2. EQUIPMENT

A device for measuring the hardness according to GOST 23677, or any other, providing the application pre-loads or loads from 9.8 to 490 N to an accuracy of ±1%.

Measuring device according to GOST 23677, or any other, providing the measurement of the diagonals of the print with precision:

±0.2 µm at 100 µm;

±1.0 µm at 100 µm 200 µm;

±0.5% at 200 µm.

3. PREPARING FOR THE TEST

3.1. For tests of specimens of small cross section or irregularly shaped produce additional support (stand).

3.2. The thickness of the layer, caslifornia with the sample surface should be at least 0.2 mm.

3.3. When measuring hardness of a sample with a curved surface must be made flat area with a minimum width of 1 mm, where you are testing. The roughness of the processed surface of the sample should be 0.2 µm according to GOST 2789.

(Changed edition, Rev. N 1).

3.4. Sample thickness should be not less than 1 mm.

3.5. The test and reference sample surface should be parallel to each other within 0.1 mm for every 10 mm of length.

(Changed edition, Rev. N 1).

4. TESTING

4.1. The tests are carried out according to GOST 2999.

4.1.1. Select the measure of hardness, having a nominal value closest to the assumed hardness of the sample.

If the average measured value differs from the value of the hardness specified at least by an amount in excess of the permissible according to GOST 23677, you should check the device and the indenter and remove the cause of the error.

4.1, 4.1.1. (Changed edition, Rev. N 1).

4.1.2. Applied load should be from 9.8 to 490 N, preferably N 294.

4.1.3. Each sample is applied to at least three of the prints are located randomly across the test surface. After the test on the back of the sample must not show noticeable signs of strain.

4.1.4. In case of detection of defects of the indenter, the test is considered invalid, and the indenter must be replaced.

5. PROCESSING OF THE RESULTS

5.1. For the hardness of the sample should be the arithmetic mean of the obtained measurements, rounded to the nearest 10 HV.

5.2. The test results are entered in the Protocol, the form of which is given in Appendix 1.

ANNEX 1 (recommended). Test report

ANNEX 1
Recommended

Test report N

The manufacturer

APPENDIX 2 (recommended). ISO 3878−83. Alloys, solid. Hardness test by Vickers

ANNEX 2
Recommended

Alloys, solid. Hardness test by Vickers

1. Appointment

This international standard specifies a method for the determination of hardness by Vickers for the solid alloys.

2. Links

GOST 9391−80 sintered hard Alloys. Methods of determination of porosity and microstructure.

3. Equipment

3.1. Measuring device, which can ensure the application of force or forces in the range of 9,807 N to 490,3 N (HV1-HV50).

3.2. The tip is a square diamond pyramid with a square base.

3.3. Measuring device for measurement of the diagonals of the prints with an accuracy of ±0.2 µm to 100 µm;

±1.0 µm to 100 µm 200 µm;

±0,5% to 200 microns.

4. Samples for testing

4.1. The thickness of the layer remote from the surface of the test sample shall be not less than 0.2 mm.

The test is carried out on a smooth, flat surface free of foreign matter and, in particular, carefully cleaned from the oil. The sample surface must be polished in accordance with GOST 9391.

The preparation of samples is carried out in such a way as to minimize the change of the surface due to hot and cold treatments.

When the hardness of the test sample with a curved surface on the sample should be prepared flat surface where you will be testing.

4.2. The thickness of the specimen to be tested shall not be less than 1 mm.

The thickness of the test sample should be sufficient to ensure that the test can be carried out without destruction or deformation of the sample under the action of given forces. For samples with small cross section or of irregular shape can be used for additional support, for example, fixation in plastic material.

5. Testing

5.1. The test is performed under the action of forces from 9,807 N (HV1) to 490,3 N (HV50), it is usually used — 294.2 N (HV30).

5.2. The test specimen is installed fixedly on a rigid support. The contact surface must be clean and free from foreign matter. It is very important that the sample is held in a stable position on the support and at the time of testing could not occur displacement of the sample.

6. Expression of results

The final result should be the arithmetic mean of the obtained values of hardness, rounded to the nearest 10 HV.

7. Test report

The test report shall contain the following information:

a) reference to this international standard;

b) information necessary to identify the test sample;

C) the results of the test;

d) any actions not specified in this international standard or are considered optional;

d) factors that could influence the results.

Note. There is no General method of exact translation of hardness by Vickers to any other scale of hardness. Therefore, these translations should be avoided, except in special cases where can be obtained a solid basis for translation by comparative tests.


APPENDIX 2. (Added, Rev. N 2).

The text of the document is verified by:
the official publication of the
M.: IPK Publishing house of standards, 1998