GOST 20487-75
GOST 20487−75 Pike. Test method for evaluation of liquid solder effect on mechanical properties of brazed material (with Change No. 1)
GOST 20487−75
Group B09
STATE STANDARD OF THE USSR
SOLDERING
Test method for evaluation of liquid solder effect
on the mechanical properties of brazed material
Brazing and soldering. Test method for evaluation of liquid
solder effect on mechanical properties of parent material
Valid from 01.01.1976
prior to 01.01.1981*
________________________________
* Expiration removed by Protocol No. 5−94
The interstate Council for standardization,
Metrology and certification (I & C N 11/12, 1994). -
Note the manufacturer’s database.
DEVELOPED by all-Union scientific-research Institute for normalization in mechanical engineering (VNIINMASH)
The Director candidate. tech. Sciences, Verchenko V. R.
Supervisor, doctor of engineering. Sciences, Professor S. V. Lashko
Performers: candidate. tech. Sciences Sirchenko N. N., Savchenko A. V.
The draft all-Union scientific-research Institute for normalization in mechanical engineering (VNIINMASH)
Director Of Verchenko V. R.
APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR of 7 February 1975 N 352
The Change N 1, approved and put into effect by the Decree of the USSR State Committee for standards from
Change No. 1 made by the manufacturer of the database in the text IUS N 5, 1981
This standard establishes the method of static tensile tests at the soldering temperature to estimate the influence of liquid solder on the mechanical properties of the brazed material to change the following:
temporary tear resistance;
the relative elongation after rupture.
1. DEFINITIONS AND NOTATION
1.1. Establishes the following definitions and notations:
a) the working length of the sample , mm — the part of the sample with the constant cross-sectional area between the sections for capture;
b) the initial gauge length of the sample before break , mm — section of the sample, which is determined by the elongation;
C) final gauge length of the specimen , mm — length calculation part after the break;
g) initial cross-sectional area of the working part of the specimen , mm;
d) rupture strength , kgf/mm, the voltage corresponding to the highest load , when the soldering temperature before the destruction of the sample;
e) elongation after rupture at the soldering temperature , % — the ratio of the increment of the estimated sample length () to its initial length;
W) a measure of the influence of the solder on the strength properties of the material , % — the ratio of the amount of change of the temporary resistance of the material in contact with the liquid solder to the magnitude of the time of resistance no solder on the surface;
h) a measure of the influence of solder on the plastic properties of the material , % — the ratio of the amount of change of the elongation of the material in contact with the liquid solder to the magnitude of relative elongation of the material without the solder on the surface.
2. THE SHAPE AND DIMENSIONS OF SAMPLES
2.1. For testing should be applied to flat samples with an initial estimated length of 25 mm.
2.2. The shape and dimensions of specimens shall be as specified in the drawing.
2.3. When cutting samples is necessary to observe the identity of the direction of the longitudinal axis of the specimens relative to the workpiece.
2.4. For the tests to be applied to samples with rough surface or handled with one hand.
Allowed, depending on the cross section of the metal and size of workpiece, surface treatment from two sides.
The roughness parameter of the machined surface at the working length should not be below 20 µm according to GOST 2789−73.
2.5. When cutting billets and the manufacturing of these samples it is necessary to take measures to prevent a possible change in the properties of the metal due to heating and hardening. Samples it is recommended to process on machine tools. Depth of cut in the last passage should not exceed 0.3 mm.
2.6. Surface preparation of samples before testing should be similar to the technological process of surface preparation prior to soldering.
2.7. The estimated length of the sample should be restricted to marks with an accuracy of 1% of its value. The mark should be applied to the surface of the specimen without contact with the liquid solder in the testing process in a way that ensures their preservation after the test.
2.8. Thickness measurement of the samples should be made with an accuracy of at least 0,01 mm, length — no more than 0.1 mm.
2.9. Measurement of thickness and width should be not less than three places the estimated length of the specimen. At least from the results obtained you must calculate the cross-sectional area rounded to the nearest 0.1.
2.10. Samples should be marked by batch number or a conditional index on the non-working parts.
3. EQUIPMENT
3.1. The quality testing machines must apply tensile or universal testing machine conforming to the requirements of this standard, GOST 7855−74 and provides:
the horizontal position of the sample during testing;
reliable centering and smooth loading of the sample;
load application to the specimen with an accuracy of ±0,1%;
the speed of mobile capture 1.0 to 2.0 mm/min.
(Changed edition, Rev. N 1).
3.2. Extension rod for mounting samples must ensure that the specimen without deflection and axial load application.
3.3. The heating device must provide a uniform heating of the sample throughout its working length to a predetermined temperature and maintaining the latter during the entire test period.
3.4. Measurement and automatic recording of temperatures shall be by thermocouples according to GOST 6616−74 and devices according to GOST 7164−78 of accuracy class not less than 0.5.
(Changed edition, Rev. N 1).
4. TESTING
4.1. Tests should be not less than five samples without solder and at least five samples with solder on the calculated length.
4.2. The solder should be placed on the calculated length of the sample and strengthen any way to avoid its displacement to the point of meltdown.
4.3. The amount of solder applied to the specimen should be 30mm.
4.4. Tests should be conducted with the flux or in the environment applicable in the relevant technological process of soldering.
4.5. To measure the temperature of the samples at the ends of their estimated length should be welded at least two thermocouples.
4.6. Deviations from the specified temperature at the estimated length for the duration of the test should not exceed:
5 °C at the heating temperature to 600 °C;
8 °C, at a heating temperature of over 600 °C.
4.7. The heating rate of the sample from the onset temperature of the melting point of the solder to a temperature test shall be not less than 30 deg/min.
4.8. To determine the strength and elongation test specimens with solder and without solder on the calculated length should be extended at the soldering temperature with a speed of 1.0−2.0 mm/min under the action of the smoothly increasing load to failure.
5. PROCESSING OF THE RESULTS
5.1. Assessing the impact of the solders on mechanical properties of brazed materials must be to change the values of temporary resistance (with solder) and elongation (with solder) material in contact with liquid solder in comparison with the values of temporary resistance (without solder) and elongation (without solder) without contact with liquid solder at the same temperature and the same rate of deformation.
5.2. The final calculated length of the sample after rupture should be determined according to the method GOST 1497−73.
5.3. Calculate values of temporary resistance, relative elongation — according to GOST 1497−73.
(Changed edition, Rev. N 1).
5.4. For the value of the temporary resistance and elongation specimens without solder and with the solder on the estimated length should take respectively arithmetic mean of five results.
5.5. A measure of the influence of the solder on the strength properties of the material () the percentage should be calculated by the formula
.
5.6. A measure of the influence of solder on the plastic properties of the material (a) in percent should be calculated according to the formula
.
5.7. Invalidate the test under the conditions set out in the standard 1497−73 and, when tested with solder, the rupture of the sample in the ground of lack of wetting by solder. In these cases, testing should be repeated. The number of samples must match the number of invalid test results.
(Changed edition, Rev. N 1).