This standard specifies the method for determining the carbon content in copper tungsten carbide vacuum contact materials. This standard is applicable to the determination of carbon content in copper tungsten carbide vacuum contact materials. Determination range: 1.00% to 5.00%. JB/T 7775.3-1995 Chemical composition of copper tungsten carbide vacuum contact materials JB/T7775.3-1995 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Chemical analysis method of copper tungsten and tungsten carbide vacuum contact materials Gas volumetric method for determining carbon content
Subject content and scope of application
This standard specifies the method for determining the carbon content in copper tungsten and tungsten carbide vacuum contact materials. JB/T7775.3—1995
This standard is applicable to the determination of carbon content in copper tungsten and tungsten carbide vacuum contact materials. Determination range: 1.00%~5.00%. 2 Reference standards
GB223.181
JB4107.185
3 Method summary
Determination of carbon content in steel and alloys
General principles and general provisions for chemical analysis methods of electrical contact materials The sample is heated in a high-temperature furnace and burned with oxygen. The generated carbon dioxide is collected in a gas cylinder, and then the carbon dioxide is absorbed by potassium hydroxide solution. The volume difference before and after absorption is the volume of carbon dioxide, which is used to calculate the carbon content. 4
Reagents and materials
Sulfuric acid (p1.84g/mL).
Potassium hydroxide solution (400g/L).
Alkali asbestos: granular.
Anhydrous calcium chloride: solid.
Oxygen: purity 99.5%.
Sodium chloride acidic solution: saturated sodium chloride solution, add a few drops of methyl orange indicator (1g/L), and add sulfuric acid until it turns red. Aluminum chloride porcelain boat: 88mm long. Burn at 1200℃ for 2h, cool, and store in a desiccator for use. Aluminum chloride porcelain tube: 600mm×25mmX22mm. Burn in sections at working temperature before use. Long hook: made of low-carbon nickel-chromium wire, used to push and pull the porcelain boat. Instruments
Carbon determination device is as shown below:
Approved by the Ministry of Machinery Industry on October 9, 1995
Implemented on January 1, 1996
JB/T7775.3-1995
1-Oxygen cylinder; 2-Pressure regulator; 3-Buffer bottle; 4-Gas washing bottle, filled with potassium hydroxide solution (4.2); 5-Gas washing bottle, filled with sulfuric acid (4.1); 6-Drying tower, filled with anhydrous calcium chloride (4.4); 7-Tube furnace; 8-Alumina porcelain tube, 9-Degassing tube, 10-Temperature controller, 11 Carbon determination instrument. 5.2 Mercury pressure gauge.
Analysis steps
6.1 Sample
Weigh the sample according to Table 1 according to the carbon content. Accurate to 0.0001g. Put the sample into the porcelain boat (4.7). Table 1
6.2 Blank test
1.00~2.00
>2.00~3.00
>3.00~5.00
Carry out a blank test with the sample.
6.3 Raise the temperature of the carbon determination furnace to 1100℃ (the furnace temperature of the block sample is raised to 1200℃), check whether the pipeline is leaking, whether the device is normal, and burn a standard sample with a carbon content similar to that of the sample to calibrate the instrument and operation. 6.4 Determination
6.4.1 Use a long hook to push the porcelain boat containing the sample into the highest temperature in the furnace, plug the rubber stopper tightly, preheat for 1 minute, operate according to the instrument operating procedures, and read the reading.
6.4.2 Open the rubber stopper, pull out the porcelain boat with a long hook, and then analyze the next sample. 7
Calculation of analysis results
Calculate the percentage of carbon according to formula (1):
C(%)=(Cr=C) K×100
Wherein:
C, reading when burning the sample, %
C. Reading of blank test, %;
K-temperature, pressure correction factor [see Appendix of GB223.1]; m-
sample quantity, g. bzxZ.net
8 Allowable difference
JB/T 7775.31995
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. The deviation of the results when calibrated with standard samples should not exceed one half of the allowable difference.
1.00~2.50
>2.50~5.00
Additional remarks:
This standard is proposed and managed by Guilin Electrical Science Research Institute of the Ministry of Machinery Industry; This standard is drafted by Shanghai Electrical Science Research Institute of the Ministry of Machinery Industry; This standard is drafted by Guilin Electrical Science Research Institute; The main drafters of this standard are Tang Yuelin
·Huang Liuqing
Song Zhanfa
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