This standard specifies the determination method of the linear expansion coefficient of flexible graphite sheets. This standard is applicable to the determination of flexible graphite sheets. JB/T 6621-1993 Determination method of linear expansion coefficient of flexible graphite sheets JB/T6621-1993 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T 6621-1993
Flexible Graphite Sheet Linear Expansion Coefficient
Determination Method
Published on 1993-05-07
Ministry of Machinery Industry of the People's Republic of China
Implementation on 1994-01-01
Mechanical Industry Standard of the People's Republic of China
Flexible Graphite Sheet Linear Expansion Coefficient
Determination Method
Subject Content and Scope of Application
This standard specifies the determination method of the linear expansion coefficient of flexible graphite sheet. This standard is applicable to the determination of flexible graphite sheet. Reference standards
GB1214
Vernier caliper
Summary of determination method
JB/T 6621-1993
This method is to put the sample with the original length measured into the quartz dilatometer, and then insert the dilatometer into the electric heating furnace. When the temperature rises to the required temperature value, start timing to keep warm. After the micrometer indication value stabilizes, record the reading, and calculate the linear expansion coefficient of the sample from the expansion value or contraction value of the sample.
4 Instruments
4.1 Quartz dilatometer
The inner diameter of the quartz outer tube is 10~11mm, and the gap between the inner and outer quartz tubes is 0.1~0.2mm. The distance between the connector and the electric heating furnace mouth is not less than 200mm. The connector and the micrometer seat are made of low expansion alloy. The sum of the pressure of the quartz inner tube and the micrometer head on the end face of the sample should be less than 15kPa. See Appendix A (reference) for the schematic diagram of the quartz dilatometer. Note: This standard recommends the use of LE-1 type linear expansion coefficient meter. 4.2 Micrometer
Range 0~1mm, indication error ±0.001mm. 4.3 Specimen end gasket
Specimen end gasket should be made of quartz sheet or low expansion alloy sheet, with a flat and smooth surface, a diameter of 10mm, a quartz sheet thickness of 1~1.5mm, and an alloy sheet thickness of 0.20-0.30mm. 4.4 Temperature measuring instrument
Division value 1~2℃.
4.5 Electric heating furnace
During the measurement cycle, the temperature of the sample area of ​​the electric heating furnace should be uniform, and the temperature fluctuation value should not exceed ±1'℃. 4.6 Vernier caliper
Should meet the requirements of GB1214, and the division value is 0.02mm. 5.1 Specimen size
Approved by the Ministry of Machinery Industry on May 7, 1993
Implemented on January 1, 1994
JB/T 6621-1993
The specimen height in the linear expansion direction and the vertical direction is 10mm. The specimen cross section is circular and can be easily placed in the outer tube of the quartz tube expansion meter. No friction or excessive gap should occur. The specimen diameter is about 10mm. 5.2 Specimen preparation
First, apply adhesive to the surface of the flexible graphite plate, with a coating thickness of no more than 0.005mm, cut into strips of approximately the specified size, and then overlap them. Use a blade and emery cloth to process the specimen into a cylinder with a diameter of 10mm and a height of 10mm. Place it in a drying oven at 350-400℃ and bake it for more than 2h. After cooling, place it in a dryer for use. 5.3 Specimen requirements
Specimens should not be delaminated, bubbling, or cracked. The two end faces should be parallel and perpendicular to the axis. Each group of specimens should be no less than 3. 6 Test steps
6.1 Use a vernier caliper to measure the original thickness of the specimen, with the reading accurate to 0.02mm. 6.2 Place the specimen in the outer tube of the quartz dilatometer, place quartz or alloy sheets on both ends of the specimen, then place the quartz inner tube, install the micrometer and micrometer base, and tap gently to stabilize the micrometer value. 6.3 Insert the quartz dilatometer into the electric heating furnace or other heat source, and wait for the sample to be heated to the specified temperature. Keep the sample temperature balanced with the temperature of the electric heating furnace. When the micrometer indication value is stable for 10 to 20 minutes, record the reading 7. Calculate the linear expansion coefficient of a single sample according to formula (1): a:
Linear expansion coefficient, ℃-\;
Where: a
AL—specimen expansion value and contraction value, mm; L. Original height of the sample, mm; Www.bzxZ.net
Lo·AT
AT—the difference between the initial temperature of the sample and the final measurement temperature, ℃. 7.2 The test results are expressed as the arithmetic mean of a group of samples, and three significant figures are taken. 7.3 If standard deviation is required, calculate according to formula (2): (x; -x)
Where: 8-
Standard deviation of linear expansion coefficient of the sample;
X—measured value of a single sample;
x—arithmetic mean of the measurement results of a group of samples; number of samples measured.
Test report
The test report should include the following contents:
Indicate the number of this standard:
Specification, brand, manufacturer:
Number of samples measured;
Test results: measured value of linear expansion coefficient; test date, personnel.
（2）
Additional instructions:
1 Thousand-minute scale:
JB/T6621-1993
Appendix A
Schematic diagram of quartz dilatometer
(reference part)
2—Scale base:
5—Quartz inner tube:
3—Connecting parts:
6, 8—Positioning gaskets;
This standard was proposed and coordinated by the Hefei General Machinery Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Shanghai Materials Research Institute of the Ministry of Machinery Industry. The main drafters of this standard were Shi Linzhang and Pu Yuezhen. 4—Quartz outer tube:
7—Test sample
People's Republic of China
Mechanical industry standard
Flexible graphite plate linear expansion coefficient
Determination method
JB/T 66211993
Published by the Mechanical Science Research Institute
Printed by the Mechanical Science Research Institute
(No. 2, Shouti South Road, Beijing
Format 880×12301/16
First edition in October 1993
Postal code 100044)
Printing sheet 1/2 Number of words 6.000
First edition in October 1993
Sold once
Number of copies 1-500
Price 2.00 yuan
Mechanical Industry Standard Service Network: http://www.JB.ac.cn66_99
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