GB/T 5586-1998 Test methods for basic properties of electrical contact materials
Some standard content:
GB/T5586-1998
GB5586-85 Basic Performance Test Methods for Electric Contact Materials" has played an important role in guiding the production and use of electric contact materials in my country and improving and stabilizing product quality since its implementation in 1986. With the development of electric contact materials, the increase in varieties and specifications, and the improvement of testing technology, this standard is no longer suitable for the current technical development level of electric contact materials in my country. Therefore, this standard has revised GB5586-85.
When revising GB5586-85, the hardness test method, resistivity measurement method and bending strength measurement method that have been proven to be applicable after many years of practice are retained, and only some unreasonable clauses are appropriately modified. For the density measurement method, the inapplicable net support measurement method is eliminated, the metal hanging wire measurement method is retained, and the density measurement method of small-volume electric contact materials is added; in addition, the conductivity measurement method is also added. There is no international standard for the basic performance test method of electrical contact materials. This standard was revised with reference to similar special standards in ISO, IEC, ASTM and other standards.
This standard includes, scope, reference standards, density measurement, hardness test, volume resistivity measurement, conductivity measurement and bending strength measurement. From the date of implementation, this standard will replace GB5586-85. This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of the Guilin Electric Science Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Guilin Electric Science Research Institute of the Ministry of Machinery Industry. The main drafters of this standard are Xie Zhongguang and Wang Liping. 1 Scope
National Standard of the People's Republic of China
Test methods for esentel
porperty of electric contact materialGB/T5586—1998
Replaces GB 5586—85
This standard specifies the test methods for density, hardness, volume resistivity, conductivity and bending strength of electric contact materials. This standard is applicable to the measurement of basic properties of various electric contact materials. 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB231-81 Metal Brinell hardness test method GB4340-84 Metal Vickers hardness test method GB5030-85 Metal small load Vickers hardness test method 3 Density measurement
3.1 Density measurement principle
The basic principle of density measurement is Archimedes' principle, that is, the buoyancy of an object immersed in a liquid is equal to the weight of the liquid displaced by the object.
3.2 Measuring instruments and materials
3.2.1 Precision balance
Weighing within 10 and below, the allowable mass weighing error is ±0.1mg weighing standard above 10g, and the allowable mass weighing accuracy is ±0.001%.
3.2.2 Instruments
The container is generally a beaker, and its size should be selected appropriately. When the sample is immersed in the liquid, the height of the liquid level rise is required to be less than 2.5mm. 3.2.3 Pycnometer
Use a pycnometer with a capacity of 10 mL.
3.2.4 Liquid
3.2.4.1 Use distilled water or deionized water to measure liquid. Its density at different temperatures in air is shown in Table 1. Approved by the State Administration of Technical Supervision on January 20, 1998, and implemented on October 1, 1998
0. 999 65
0. 999 60
0. 999 49
0. 999 43
0. 999 24
GB/T 5586—1998
Table 1 Density of distilled water or deionized water in air at different temperatures
0. 998 94
0. 998 68
3.2.4.2 During the measurement process, the liquid temperature must be kept in balance with the ambient temperature. 3.2.5 Thermometer
The accuracy is ±0.5℃.
3.2.6 The diameter of the thin metal wire
must not exceed 0.25mm.
3.3 Test specimen
0. 998 20
0. 998 10
0. 997 77
0. 997 65
0. 997 42
0. 997 29
0. 997 17
3.3.1 The surface of the test specimen must be smooth and free of oil stains. If the test specimen has a coating, the coating must be cleaned before measurement. Density
0. 997 04
0. 996 91
0. 906 78
0.99号65
0. 995 94
n99580
3.3.2 The volume of the sample must be greater than 0.5 cm, otherwise several samples (total volume greater than 0.5 cm) should be measured together. 3.3.3 The temperature of the sample must be consistent with the ambient temperature. 3.4 Measurement
3.4.1 Density measurement of large volume (volume greater than 0.5 cm) electrical contact material 3.4.1.1 Weigh the mass of the clean + dry sample in air (mo). 3.4.1.2 For samples that absorb water when weighed in water, put the sample in liquid paraffin without bubbling, then take the sample out of the liquid paraffin and wipe off the excess liquid paraffin on the surface with filter paper; or use a thin layer of vaseline on the surface in a beneficial way. Then weigh its mass mi in the air.
3.4.1.3 As shown in Figure 1, suspend the sample in water with a thin metal wire. The sample should be no less than 10mm above the water surface. Exclude the bubbles on the sample surface and attached to the metal wire, and then weigh the mass ㎡2 of the sample in water. 3.4.1.4 Place the sample in water and weigh the mass m3 of the metal wire in water. Figure 1 Schematic diagram of weighing in water
3.4.1.5 Measure the temperature t of the liquid.
3.4.1.6 Results and calculations
The density of the non-absorbent sample is calculated according to formula (1): GB/T 5586-1998
The density of the absorbent sample is calculated according to formula (2)
(1), (2) Where:
1)——density of the sample, g/cm\;
D.——density of the liquid at temperature t, g/cmm--mass of the sample in air, g;
mo-(mg-m)
m, -(mz -m,)
mThe mass of the absorbent sample in air after waterproofing treatment, g;m2--mass of the sample in water (including metal wire), gms--mass of the metal wire in water, g. The calculation result shall be rounded to one decimal place.
3.4.2 Measurement of the density of small volume (volume less than or equal to 0.5cm2) electrical contact materials 3.4.2.1 Weigh the mass mc of the clean and dry sample in air. ()
3.4.2.2 For the sample that absorbs water when weighed in water, treat it according to the method in 3.4.1.2, and then weigh its mass m1a in air
3.4.2.3 Weigh the mass mz of the pycnometer filled with liquid. 3.4.2.4 Place the sample in the pycnometer filled with liquid, first remove the bubbles on the surface of the sample, and then weigh its mass ma. 3. 4.2. 5 Measure the temperature t of the liquid.
3. 4. 2. 6 Results and calculations
The density of the non-absorbent sample is calculated according to formula (3): ma
The density of the absorbent sample is calculated according to formula (4): ma
mi + m2
(3), (4) In the formulas:
Density of the sample, s/cm\;
Density of the liquid at temperature:, g/cm; De
Mass of the sample in the air, g;
-Mass of the absorbent sample in the air after waterproofing, *mt
mz—Mass of the pycnometer filled with liquid, g; m—Mass of the pycnometer filled with liquid after the sample is placed, 8. The calculation result should be two decimal places.
4 Hardness test
4.1 Test principle
4.1.1 Brinell hardness test principle
GB/T 5586—1998
Use a steel ball of a certain diameter to press into the surface of the sample with the corresponding test force. After the specified holding time, remove the test force and measure the diameter of the indentation on the surface of the sample. The Brinell hardness value is the quotient obtained by dividing the test force by the surface area of the indentation sphere, calculated using formula (5): HBS=
Wu Zhong, HBS—Brinell hardness,MPat
F—test force, N;
D—steel ball diameter, mm
d—average diameter of the indentation, mm
4.1.2 Principle of Vickers hardness test
DD-/D-)
A four-sided diamond head with an angle of 136° between the opposite faces is pressed into the test surface with the selected test force. After maintaining the test force for a specified time, the test force is removed and the length of the two diagonals of the indentation is measured. The Vickers hardness value is the quotient obtained by dividing the test force by the surface area of the indentation, calculated using formula (6):
HV=1.8544 years
Where: HV Vickers hardness, MPa
F test force, N;
d—average diagonal diameter of the indentation, mm.
4.2 Test device
4.2.1 Brinell hardness tester, indenter and positive mark measuring device shall comply with the requirements of GB231. 4.2.2 Vickers hardness tester, indenter and indentation measuring device shall comply with the requirements of GB5030 or GB4340. 4.3 Test specimen
4.3.1 The test surface and back of the test specimen shall be smooth and flat, without burrs, oil stains or other external contamination. -(6)
4.3.2 The surface roughness of the test surface must ensure that the indentation can be accurately measured. The surface roughness of the general test surface is: Brinell hardness test R, ≤0.8u Vickers hardness test R0.2um,
4.3.3 The thickness of the test specimen or test layer shall not be less than 10 times the depth of the indentation. After the test, no visible deformation marks shall appear on the back of the specimen. 4.4 Test
4.4.1 The specimen support surface, the surface of the indenter and the test bench surface should be clean. The specimen should be firmly placed on the test bench. No displacement or vibration is allowed during the test.
4.4.2 During the test, the test force should be applied evenly and smoothly. No impact or vibration is allowed. The direction of the test force should be perpendicular to the test surface. 4.4.3 The time for applying the test force is 2 to 85 seconds. The holding time is (30±2) seconds. 4.4.4 For Brinell hardness specimens, the distance between the center of the positive mark and the edge of the specimen should not be less than 2.5 times the diameter of the indentation, and the distance between the centers of adjacent indentations should not be less than 4 times the diameter of the indentation.
4.4.5 For Vickers hardness specimens, the distance between the center of the indentation and the edge of the specimen or the center of adjacent indentations should not be less than 5 times the diagonal of the indentation. 4.4.6 After removing the test force, the diameter of the Vickers hardness indentation should be between 0.24D and 0.6D. 4.4.7 The Brinell hardness shall be measured in two mutually perpendicular directions with the indentation diameters. The maximum difference between the two indentation diameters shall not exceed 2% of the smaller diameter. 4.4.8 The Vickers hardness shall be measured in two diagonal lengths. The difference between the lengths shall not exceed 5% of the shorter diagonal length. 4.5 Results and calculations
The Brinell hardness value shall be calculated using the arithmetic mean of the two indentation diameters, and the Vickers hardness value shall be calculated using the average of the indentation diagonals. The test results are rounded to two decimal places.
5 Volume resistivity measurement
5.1 Measurement principlebzxz.net
GB/T 5586—1998
5.1.1 Volume resistivity is the resistance of a conductor per unit length and unit cross-sectional area. The formula is as follows: p
Wherein: pVolume resistivity of sample, μn·cmtR-resistance value of sample.:
A—--average cross-sectional area of sample.cm;
L——length of sample, cm.
5.1.2 Resistivity measurement adopts the basic principle of a double-arm bridge. The measurement circuit is shown in Figure 2. R
G galvanometer: A-ammeter; RI, R2——bridge comparison resistor: R;, R. bridge ratio arm resistor; R-variable resistor; R-sample resistor, R-standard resistor; E-current-stabilized power supply; K-knife switch Figure 2 Double-arm bridge circuit diagram
5.2 Measuring instruments and fixtures
5.2.1 Double bridge with an accuracy of 5/10,000 and its matching galvanometer and photoelectric amplifier. 5.2.2 Standard resistor with a resistance of 0.001n and an accuracy of not less than 0.01. 5.2.3806A sliding wire resistor or corresponding variable resistor box. +(7)
5.2.4 Special measuring fixture: The special fixture for measuring 50mm×10mmXhmm strip specimens is shown in Figure 3, and the special fixture for measuring base wire or strip is shown in Figure 4.
1—Compression nut: 2—Upper bracket: 3—Potential terminal: 4—Specimen 5—Current terminal; 6—Base; 7—Nut; 8—Screw Figure 3 Schematic diagram of 50 mm×10 mm×h mm specimen fixture 5.3 Test
5.3.1 Strip specimen
GB/T 5586—1998
1—Base; 2—Screw; 3 Specimen; 4 Potential terminal 5—Current terminal; 6—Compression screw
Figure 4 Schematic diagram of wire strip specimen fixture
5.3.1.1 The specimen size is 50 mm×10 mm×h mm (the thickness of the silver metal oxide specimen of the alloy internal oxidation method is the thickness of the semi-finished product sheet, and the thickness of the specimen of other electrical contact products is 4 mm). The cross-sectional area size deviation should not exceed 1% of its average value, and the end face line should not be greater than 0.1.
5.3.2 Wire and strip test specimens
5.3.2.1 The length of wire and strip test specimens shall be greater than or equal to 300mm, and the cross-sectional area at any position along the measuring length shall not be greater than 3% of its average value.
5.3.2.2 The resistance value of the test specimen on the measuring length between the two potential ends shall not be less than 100u. 5.3.3 The surface of the test specimen shall not have cracks or other defects, oxidation, oil pollution and other pollution, and the roughness R. shall be less than 3.2um. 5.4 Measurement
5.4.1 Measure the width, thickness or diameter of the two potential ends of the test specimen and the three points in the middle, with an accuracy of 0.01mm. The cross-sectional area of the test specimen shall be calculated using the arithmetic mean of the data measured at the three points.
5.4.2 Measure the distance between the two potential ends with an accuracy of ±0.1%. 5.4.3 After the test specimen is fixed in the fixture, the test specimen must have good contact with the two current and potential ends. 5.4.4 The selection of working current should not cause the sample to heat up. Under the premise of ensuring the measurement sensitivity, the minimum T should be selected as the current. 5.4.5 In order to eliminate the influence of contact potential, the resistance should be measured on the positive and negative sides of the current, and the average value should be taken. 5.4.6 Repeatedly measure the sample three times, and take the arithmetic mean of the three measurements as the measured resistance value. 5.5 Results and calculations
The resistivity is calculated according to formula (8):
In the formula: @—sample volume resistivity.ml·cm, R,——sample resistance value + mp;
A——sample average cross-sectional area, cm;
L-distance between the two potential ends of the sample, cm.
The calculation result is rounded to two decimal places.
6 Conductivity measurement
6.1 Measurement principle
The conductivity measurement method is the vortex method. The eddy current method uses the AC bridge balance principle for measurement. Its circuit diagram is shown in Figure 5. GB/T5586-1998
5 AC bridge circuit diagram
When a detection coil (test probe) with a certain frequency is placed on the gold screen block, the coil electromagnetic field induces eddy currents on the metal surface. The size of the eddy current is related to the conductivity of the metal being measured. The eddy current magnetic field (induced magnetic field) reacts to the detection coil to weaken the magnetic field of the detection coil. The conductivity of the metal is different, and the degree of weakening is also different. The change of the magnetic field of the detection line diagram is bound to destroy The balance of the bridge, when readjusted (2), can make the bridge reach a new balance. If the value of is related to the conductivity of the metal, the absolute value of the conductivity that has been calibrated in advance can be directly read from the angular division of C.
6.2 Measuring instrument
Eddy current conductivity meter, measuring range (5~62)MS/m, instrument accuracy ±1%. 6.3 Sample
6.3.1 Sample size, thickness should not be less than 1mm, circular diameter should not be less than 10mm, rectangular side length should not be less than 10mm×10 mm.
6.3.2 The surface of the sample should be flat, without any oil stain or oxide layer (except silver metal oxide). If there is an oxide layer, it must be ground off with fine sandpaper and wiped clean.
6.3.3 The sample cannot contain ferromagnetic materials.
6.4 Measurement
6.4.1 Use a standard block to calibrate the high and low values of the instrument 2 to 3 times. 6.4.2 Place the operator on the surface of the sample to be tested, turn the dial so that the meter pointer is at zero, and read the sample from the dial. Conductivity. 6.4.3 Measure 3 to 5 points on different parts of the sample surface. 6.5 Results and calculations
The measurement results are calculated by arithmetic mean and rounded to two decimal places. 7 Flexural strength measurement
7.1 Measurement principle
The basic principle of flexural strength measurement is to measure the maximum bending of the sample when it breaks under the slow action of the load in the middle of the span. 7.2 Measuring instruments and fixtures
7.2.1 Material testing machine: The indication error should not be greater than 1%. 7.2.2 The bending fixture (as shown in Figure 6) has a span of (25 ± 0.2) mm, a bearing column diameter of (3 ± 0.1) mm, and is made of hardened steel or cemented carbide with a Vickers hardness value of not less than 700. 7.3 Specimen requirements
7.3.1 The hardness of the entire section of the specimen is uniform. 7.3.2 The specimen size is 50mm×10mm×4mm, and the dimensional deviation in the length direction should not be greater than 0.1mm. 7.3.3 The specimen is not allowed to have deformation, bending, edge loss or other surface defects. 7.4 Measurement
7.4.1 Measure the distance between the two supporting points of the specimen, accurate to 0.01mm. 7.4.2 Measure the width and length of the two supporting points and the midpoint of the specimen, accurate to 0.01mm, and the cross-sectional area is calculated using the arithmetic mean of the data measured at the three points.
7.4.3 Place the specimen on the supporting rollers in a 50mm×10mm plane so that the longitudinal axis of the specimen is perpendicular to the longitudinal axis of the rollers. Then slowly and steadily apply the load between the two supporting rollers until it breaks. The time from the start of the load application to the failure of the specimen should not be less than 10.
7.5 Results and calculations
The bending strength is calculated according to formula (9):
Where: ou bending strength, N/mm\
F—load applied when the specimen fails, N,
3—test width, mm
h—test thickness, mm,
L—distance between the two supporting points, mm.
The measurement result shall be rounded to two decimal places.
+ +**+*++*+*+++.++++++++++++*+( 9)Figure 6 Schematic diagram of the bending clamp
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