GOST 25281-82
GOST 25281−82 powder metallurgy. The method of determining the density of the moldings (with Change No. 1)
GOST 25281−82*
_______________________
* The designation of the standard.
Changed the wording, Rev. N 1.
Group B59
STATE STANDARD OF THE USSR
POWDER METALLURGY
The method of determining the density of the moldings
Powder metallurgy. Method of determination of formings density
Valid from 01.01.1983
before 01.01.1988*
_______________________________
* Expiration removed
according to the Protocol of the Intergovernmental Council
for standardization, Metrology and certification
(IUS N 2, 1993). — Note the manufacturer’s database.
DEVELOPED by the Academy of Sciences of the Ukrainian SSR
PERFORMERS
V. N. Klimenko, I. D. Radomyslsky, M. B. Stern, M. Simonovic
INTRODUCED by the Academy of Sciences of the Ukrainian SSR
Academician G. E. Pukhov
APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards, dated may 27, 1982 N 2156
AMENDED No. 1, adopted by the Interstate Council for standardization, Metrology and certification (Protocol No. 6 dated 21.10.94). The state developed by Russia. By the resolution of Gosstandart of Russia from
Change No. 1 made by the manufacturer of the database in the text IUS N 6, 1999
This standard specifies a method for determining the density of the moldings of metal powders.
The method involves measuring the mass forming the air and water with the subsequent determination of its volume and density.
The standard does not apply to the forming of hard alloys, produced by powder metallurgy.
(Changed edition, Rev. N 1).
1. SAMPLING METHOD
1.1. Sampling is carried out according to normative-technical documentation for products.
1.2. The volume of sample for test should be at least 0.5 cm.
1.3. If the volume of one sample is less than 0.5 cm, for a single determination of density, take several samples with a total volume of at least 0.5 cm
. The density of the moldings is determined based on the total mass and volume.
(Changed edition, Rev. N 1).
1.4. The sample surface must be carefully cleaned of grease and other contaminants.
1.5. For castings weighing over 0.5 kg may be used as samples for testing parts in accordance with the requirements of paragraph 1.2. The requirements for the selection of individual parts of the mold for testing must be specified in normative and technical documentation on specific product.
1.6. Samples (moulding), the volume of which can be calculated from measured primary dimensions must have tolerances on the dimensions with an accuracy not below 10-th class according to GOST 25347−82.
1.5, 1.6. (Added, Rev. N 1).
2. EQUIPMENT AND MATERIALS
Laboratory scales and others that provide measurement of the mass of the mold with a tolerance of not more than 0.01%.
The device for weighing is given on features.1, 2.
Damn.1 — Device for weighing in air
The weighing device in the air
Damn.1
Damn.2 — a Device for weighing in water
Apparatus for weighing in water
Damn.2
The wire should be of non-corrosive material with a diameter of 0.25 mm. the Basket shall be made of the same wire with a minimum number of threads.
Distilled water GOST 6709−72, adding one or two drops of an aqueous solution of a wetting agent with a mass fraction of 0.1%.
Paraffin according to GOST 23683−89.
Filter paper according to GOST 12026−76.
Substance, wetting OP-7 or OP-10 GOST 8433−81.
Thermometer type t-62А1−8 according to GOST 302−79* used for temperature measurement of air and water with an error of not more than 0.5 °C.
________________
* On the territory of the Russian Federation GOST R 52921−2008. — Note the manufacturer’s database.
(Changed edition, Rev. N 1).
3. TESTING
3.1. The test is carried out at a temperature of 15−30 °C.
3.2. To determine the density of the molding is weighed with an error not more than 0.01%.
(Changed edition, Rev. N 1).
3.3. Mass forming is determined by weighing in air.
3.4. Surface pores forming close, soaking her in melted paraffin or other substance. For this purpose the molding is completely immersed in melted paraffin and allowed to stand for at least 30 s before the termination of allocation of bubbles. Then the molding was dried in air to constant weight and cleanse the surface from the paraffin filter paper. The use of other substances for closure of surface pores forming — according to GOST 18898−89.
(Changed edition, Rev. N 1).
3.5. Weigh the soaked, dried and purified forming in the air.
3.6. Weigh the soaked, dried and purified forming in water containing a wetting agent. For this purpose the molding is hung on a wire or placed in a basket and immersed into a vessel with distilled water so that she was completely covered with water. On the surface of the forming wire or baskets should be free of air bubbles.
3.7. The water temperature is measured with an error of not more than 0.5 °C. the Density of water at different temperatures in the reference application.
3.6, 3.7. (Changed edition, Rev. N 1).
3.8. You can define the volume of the moldings according to the measurements of their basic dimensions. In this form, meet the requirements of section 1.6, measured according to GOST 8.051−81.
(Added, Rev. N 1).
4. PROCESSING OF THE RESULTS
Density molding (), g/cm
, calculated by rounding up to 0.01 according to the formula
where is the mass moulding, suspended in air, g;
,
is the mass of the impregnated molding, weighed in air and in water, g;
is the density of water, g/cm
.
When defining a volume forming a computational method density molding is calculated by the formula
where — the volume of the moulding, cm
.
(Changed edition, Rev. N 1).
APPLICATION (reference). THE DEPENDENCE OF WATER DENSITY FROM TEMPERATURE
APP
Reference
| Temperature, °C |
The density of water, g/cm |
| 15 | 0,9981 |
| 16 | 0,9979 |
| 17 | 0,9977 |
| 18 | 0,9976 |
| 19 | 0,9974 |
| 20 | 0,9972 |
| 21 | 0,9970 |
| 22 | 0,9967 |
| 23 | 0,9965 |
| 24 | 0,9963 |
| 25 | 0,9960 |
| 26 | 0,9958 |
| 27 | 0,9955 |
| 28 | 0,9952 |
| 29 | 0,9949 |
| 30 | 0,9946 |
