GOST 20018-74

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  ГОСТ 20018-74

GOST 20018−74 (ST SEV 1253−78, ISO 3369−75) sintered hard Alloys. Method for determining the density (with Amendments No. 1, 2, 3)

GOST 20018−74*
(ST CMEA 1253−78,
ISO 3369−75)**
______________________
** The designation of the standard.
Changed the wording, Rev. N 3.

Group B59

STATE STANDARD OF THE USSR

SINTERED HARD ALLOYS

Method of determining density

Sintered hardmetals. Determination of densitu

AXTU 1909

Date of introduction 1976−01−01

The decision of the State Committee of standards of Ministerial Council of the USSR of July 30, 1974 N 1834 the introduction installed from 01.01.76

Proven in 1985 by the Resolution of Gosstandart from 19.06.85 1728 N validity extended to 01.01.91**
________________
** Expiration removed by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (I & C N 11/12, 1994). — Note the manufacturer’s database.

* REVISED (July 1986) with Amendments No. 1, 2, approved in August 1981 and June 1985 (IUS sizes 11−80, 9−85).

AMENDED N 3, approved and put into effect by the Decree of the USSR State Committee on management of quality and standards from 30.10.90 N 2735 with 01.03.91 in Annex 4 from 01.01.93

Change No. 3 made by the manufacturer of the database in the text IUS N 1, 1991


This standard specifies a method for determining density at temperature from 288 to 303 K (15 to 30 °C) sintered hard alloys with a volume of at least 0.5 cm, and weight not more than 200 g.

The method consists in weighing the sample in air and then in water and calculate its density.

The standard fully complies ST SEV 1253−78.

Allowed the hardness of hard alloys according to the international standard ISO 3369−75 given in Appendix 4.

(Changed edition, Rev. N 1, 3).

1. SAMPLING METHOD

1.1. Sampling is carried out according to GOST 20559−75.

If the volume of one sample is less than 0.5 cm, for a single determination of density of select a few samples with a total volume of at least 0.5 cm, while the volume of each sample should be at least 0.05 cm.

(Changed edition, Rev. N 1).

1.2. The sample surface must be thoroughly cleaned from grease, oil and dirt.

(Changed edition, Rev. N 1).

2. EQUIPMENT

2.1. A device for determining the density consists of two main parts:

weights with weights with an error of less than 0.001 g, the weights should have a density not lower than 7 g/cm;

device for weighing in water, consisting of a vessel with the fluid and wire baskets for immersion of sample in liquid (Appendix 1).

Wire of non-corrosive material for hanging the sample in to the rocker scales with a diameter of not more than 0.25 mm. the Basket shall be made of the same wire.

(Changed edition, Rev. N 1).

2.2. The liquid for weighing use distilled or preferably deionized and degassed water, to which add one or two drops of the substance to improve the wettability. Allowed to use other fluids if their density is in the prescribed testing temperature range known to the fourth decimal place.

(Added, Rev. N 1).

3. TESTING

3.1. The temperature of the distilled water are measured with an accuracy of up to 1 K (1 °C) and determine its density by the application table 2.

(Changed edition, Rev. N 1).

3.2. The sample is weighed in air with an error of not more than 0.001 g.

3.3. The sample is suspended on a thread or wire, or placed in a basket and immersed in a container of water so that he was completely covered with water. Immersion depth must be at least 10 mm from the top of the sample. A sample (filament, wire, basket) must not be air bubbles.

Removal of air bubbles is pre-immersed sample (wire basket) into the water.

(Changed edition, Rev. N 1).

3.4. The sample is weighed in water with an error of not more than 0.001 g.

Note. Before each weighing, check the zeroing of weights, when the thread (wire basket) for the suspension of samples immersed in water.

4. PROCESSING OF THE RESULTS

4.1. The density of the sample kg/m(g/cm) mass per unit volume of material, calculated by the formula

,

where is the mass of the sample suspended in air, g;

the mass of the sample suspended in water, g;

is the density of water, kg/m(g/cm).

(Changed edition, Rev. N 2).

4.2. The density calculation is carried out with an accuracy of at least 0.01 g/cm.

4.3. The density of the party taking the arithmetic mean of definitions, rounded to 0.01 g/cm.

4.4. The test results are entered in the Protocol, the form of which is given in Annex 3.

APPENDIX 1. DEVICE FOR WEIGHING SAMPLES (BASKET, WIRE)

ANNEX 1

Damn.1

Damn.2

APPENDIX 2. The density of water at different temperatures

ANNEX 2

(Changed edition, Rev. N 1, 2).

APPENDIX 3. TEST REPORT

APPENDIX 3

TEST REPORT N

(Changed edition, Rev. N 2).

APPENDIX 4 (recommended). SINTERED METAL MATERIALS ARE IMPERVIOUS AND HARD ALLOYS

ANNEX 4
Recommended

Determination of density

Impermeable sintered metal materials and hardmetals
Determination of density

1. Purpose and scope

This international standard describes the method of determining the density of impermeable sintered metal materials and hard alloys.

2. Links

ISO 4489−78 Sintered hard alloys. The sampling and testing.

ISO 4884−78 Hard alloys. Sampling and testing of powders for sintered samples.

3. The essence

Weigh the test sample is carried out first in air then in the liquid to determine its density by calculation.

4. Device and materials

4.1. Precizionnye scales, accurate readings to ±0.1 mg at the sample mass is 10 g and ±0.001% of weight of sample over 10 g.

Sample should be calibrated and have a density of not less than 7 g/cm.

4.2. Device from the grating or wire given on features.1 and 2. In each case, the maximum wire diameter should be 0.2 mm. thicker wire can be used if necessary to maintain the test sample.

Damn.1

Damn.2

4.3. Vessel for weighing in liquid. For weighing test specimens weighing less than 10 cmrequires a vessel that provides the raising of the level of the liquid in the immersion of the test sample is not less than 2.5 mm.

4.4. Distilled, deionized, and preferably degassed water, which added 1 or 2 drops of a wetting reagent.

The values of density of distilled water depending on the temperature

Notes:

1. You can use other fluids if their density in air at the test temperature is known with accuracy up to four decimal places.

2. When using the brass hitch on the air, the value on 0,00106 g/cmis less than the true density of water, measured in vacuum.

5. The test sample

5.1. Sampling should be conducted in accordance with ISO 4489−78 or ISO 4884−78.

5.2. The volume of the test sample should be at least 0.5 cm. If you want to determine the density of a sample volume of less than 0.5 cm, for a single definition it is possible to take several samples, and the volume of each individual sample shall be not less than 0.05 cm.

5.3. The surface of the test sample must be thoroughly cleaned from adhering foreign material, e.g. dirt, oil, grease.

6. Testing

6.1. Place the test sample on the top grill (Fig.1) or bowl (Fig.2). The lower grille needs to be fully immersed, the wire freely hanging off the side of the bowl and needs to be partially immersed in the liquid. Remove all bubbles of air and weigh ().

6.2. Place the test sample on the lower bars (Fig.1) or hang it using the wire (damn.2). Immerse the test sample in a vessel containing liquid, so that only the wire touched the liquid surface. Remove all bubbles of air and weigh.

6.3. Precision weighing for batches weighing up to 10 g is 0.1 mg, and for batches weighing more than 10 g is 0.001%.

6.4. When conducting the weighing, the temperature of the test fluid sample and the ambient air must be the same. The temperature of the liquid should be determined. If you use distilled water its density must be defined according to claim 4.1.

7. Processing of the results

Density of test sample in grams per cubic centimeter is determined by the formula

,

where is the mass of the test sample determined at the weigh-in;

is the fluid density of air, g/cm;

 — the mass of the fluid volume displaced by the sample placed in the liquid is equal to the difference between the mass of the sample weighed in the air, and the sample suspended in water,

Test results are rounded to the second decimal place.

8. Test report

The test report must include:

1) a reference to this international standard;

2) all information relating to the identification of the test sample;

3) the results obtained;

4) all operations not specified in this international standard or regarded as optional.

ANNEX 4. (Added, Rev. N 3).