GOST 26529-85
GOST 26529−85 (ST SEV 4656−84) Materials powder. Test method for radial compression
GOST 26529−85
(ST CMEA 4656−84)
Group B59
STATE STANDARD OF THE USSR
MATERIALS POWDER
Test method for radial compression
Powder materials. Radial crushing test method
AXTU 1909
Valid from 01.07.86
before 01.07.96*
_______________________________
* Expiration removed
Protocol 5−94 N Interstate Council
for standardization, Metrology and certification
(IUS N 11/12, 1994). — Note the manufacturer’s database.
DEVELOPED by the Academy of Sciences of the Ukrainian SSR
PERFORMERS
V. N. Klimenko, I. M. Fedorchenko, A. E. Kushchevsky, M. Simonovic, A. T. Pekarík, V. A. Reytor, L. D. Bernatsky
INTRODUCED by the Academy of Sciences of the Ukrainian SSR
Academician I. K. Pokhodnya
APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards, dated 24 April 1985, No. 1171
This standard specifies a method for determining the tensile strength in radial compression of the sample of powder materials at a temperature of (
The method consists in determining the maximum load prior to failure of the specimen or the appearance of a crack under radial compression and the calculation of the maximum stresses occurring in the sample under the action of the load.
This standard does not apply to powder hard alloys and materials based on refractory compounds.
The standard fully complies ST SEV 4656−84.
1. SAMPLING METHOD
1.1. Method of sampling and preparation of samples for tests according to normative-technical documentation for powder materials with the additions specified in paragraphs.1.1.1−1.1.6.
1.1.1. Samples should be manufactured and impregnated, if necessary, with oil under the same conditions as the finished product.
It is possible to produce samples of the finished products by machining.
Samples for testing can be the finished product.
1.1.2. Mechanical treatment should avoid changing the material properties of the samples due to heating, work hardening and other factors and shall be specified in regulatory technical standards on specific products.
1.1.3. Samples for testing must be in the form of a hollow cylinder, on the specified features.1.
Damn.1
1.1.4. The wall thickness of the specimen () should not be less than 2 mm. the ratio of wall thickness to its outer diameter (
) must be less than
.
1.1.5. Sample length () needs to be at least twice the value of the thickness of its walls.
1.1.6. Deviations of dimensions of test specimens from the nominal must be not rougher than class II according to GOST 25347−82. The deviation of the shape and the location of the surfaces of the individual samples must be within the fields of tolerances on their size.
1.1.7. The test at least three samples, if a different number of samples is not specified in the normative-technical documentation on powder materials.
2. EQUIPMENT
Universal testing machine or a machine for compression testing with an error not more than 1% according to GOST 7855−74.
Pressure cookers with ball adaptor for compression testing, meet the following requirements:
the sizes of the pressure plates must exceed the outer diameter of the sample and to go beyond its length;
the surface hardness of the pressure plates must be greater than the hardness of the test specimens.
3. PREPARING FOR THE TEST
3.1. Before the test the samples are subjected to visual inspection without using of magnifying means. On the surface of the samples shall be free of protuberances, dents, cracks, delamination, inclusions, cavities and mechanical damage.
3.2. The thickness, outer diameter and length of the sample is measured in at least three equidistant from each other places with an error of not more than established when measuring linear dimensions according to GOST 8.051−81 and calculates the mean arithmetic thickness, width and outer diameter.
According to the average of the received values of the dimensions calculate the thickness, outer diameter and length of the sample.
4. TESTING
4.1. Sample for test is placed between the pressure plate of the testing machine in such a way that it was in the center of the plates, as indicated on the devil.2.
Damn.2
4.2. Loading the sample produced smoothly and continuously.
The loading rate of the sample is selected in the range from 2 to 20 MPa/s so that the time from start of loading to failure of the sample was at least 10 seconds.
4.3. Destroy the sample and is determined by the scale of the testing machine maximum load prior to its destruction.
The test is considered valid if the relative deformation of the sample in the direction of the radial compression does not exceed 10%, and the load at the time of the destruction of the sample or the appearance of a crack is reduced abruptly.
5. PROCESSING OF THE RESULTS
5.1. Tensile strength in radial compression of the sample () (the maximum voltage that occurs at the time of destruction or until it cracks) in megapascals is calculated by the formula
where — the maximum load prior to the time of the destruction of the sample or until it cracks, N;
— outer diameter of sample, mm;
the wall thickness of the specimen, mm;
— length of sample, mm.
5.2. For the value of the tensile strength under radial compression be the arithmetic mean of the results of testing at least three samples.
The magnitude of the maximum tensile radial compression on a specific product can be determined in accordance with the recommended application.
5.3. The results of calculations are rounded to the first decimal place.
5.4. The test results recorded in a Protocol containing:
the brand of material;
the numbers of the patterns;
the dimensions of the samples;
terms and method of manufacturing samples;
impregnation of samples;
test temperature;
tensile strength in radial compression of each sample;
the arithmetic mean of the results of the test;
the designation of this standard;
the testing date.
APPLICATION (recommended). THE RELATIONSHIP OF TENSILE STRENGTH IN RADIAL COMPRESSION OF THE SAMPLE WITH ULTIMATE STRENGTH IN LATERAL BENDING OF THE MATERIAL FROM WHICH THE RESULTING SAMPLE, AND THE ACCURACY OF THE METHOD
APP
Recommended
THE RELATIONSHIP OF TENSILE STRENGTH IN RADIAL COMPRESSION OF THE SAMPLE () WITH TENSILE STRENGTH TRANSVERSE BENDING OF THE MATERIAL (
), FROM WHICH THE RESULTING SAMPLE, AND THE ACCURACY OF THE METHOD
Test radial compression of the sample in the form of a hollow cylinder until the specimen breaks or until it cracks is a variation of the method of determining the tensile strength of the sample material bending in conditions of complex stress state. The exact formula for determining the ultimate strength under radial compression () of the sample material the following:
where 
Difference formulas (1) proposed by the present standard approximate formulas for the processing of test results is determined by the ratio
where 
The multiplier for bushings with various relationships
changes as shown on the devil.1.
Damn.1
As less
, determined according to GOST 18228−84 7−12%, the ratio of (2) is helpful when selecting specific values
to control products in terms of production. The distinction between
and
can be large, due to the influence of the scale factor (size of samples) on test results.
The error method is not more than 1.4%.
The change in the error of the method the size of samples given on features.2.
Damn.2
