GB 3074.3-1982 Determination of oxidizability of graphite electrode

Oxidizability refers to the number of milligrams of graphite sample lost by oxidation per gram of sample per hour at a temperature of 6501C. GB 3074.3-1982 Determination of oxidizability of graphite electrodes GB3074.3-1982 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Method for the determination of the oxidation resistance of graphite electrodes
1 Definition
621.35.035.2
:661.666.2
GB 3074.3-82
Oxidation resistance refers to the number of milligrams lost by oxidation per gram of graphite sample per hour at a temperature of 650℃. 2 Instruments and materials
2.1 Electro-optical analytical balance: weighing 200g, sensitivity 0.1mg. The weighing end of the balance is modified to suspend the graphite sample. 2.2 Reactor: temperature above 650℃.
2.3 Quartz tube: outer diameter 64mm, inner diameter 56mm, length 900mm. 2.4 Automatic temperature controller: control accuracy ±1℃. 2.5 Rotor flowmeter: 0～21/min.
2.6 Civilian blower: 40W.
2.7 Nitrogen: purity above 99.99%.
3 Sample
3.1 Size: cylindrical sample with a diameter of 26mm and a length of 50mm, with a processing accuracy of ±0.5mm. 3.2 Requirements: 8mm away from one end of the sample, drill a hole with a diameter of 1mm along the extrusion direction as a clamping sample, then wipe the sample with alcohol and place it in a drying oven at 120～130℃ to dry it, measure the false specific gravity, and finally place the sample in a dryer for measurement. 3.3 Sampling position: Take a sample with a diameter of 80mm and a length of 150mm parallel to the extrusion direction at the center of the end of the electrode to be measured, remove 70mm from the outer end, and use the remaining cylinder to divide it into two equal parts along the extrusion direction. 3.4 Quantity: Take 4 samples each time.
4 Test steps
4.1 The sample is suspended in the constant temperature zone of the quartz tube with a platinum wire of 0.3mm diameter, and the upper end is connected to the hook of the balance. 4.2 Place the test end of the thermocouple in the middle of the side of the sample against the inner wall of the quartz tube, and cover the upper end of the quartz tube with a graphite cover. Before the measurement, check that the sample cannot touch the thermocouple and the quartz cover, and then turn on the power. 4.3 After the furnace is heated to 400℃, start to pass nitrogen from the lower end of the quartz tube (flow rate is 0.51/min), and continue to heat up until the temperature in the furnace reaches 650±1℃, stop passing nitrogen, replace with dry air (flow rate is 2l/min), pass for 2~3min, weigh, record the weight (sample weight), and start timing.
4.4 Record the weight every half an hour to check whether the measurement is normal. After oxidizing for 4 hours, you can turn off the power, stop passing air, and take out the sample.
5 Calculation formula and test error
5.1 Calculation formulabzxz.net
The oxidizability of the sample (mg/g·h) is calculated as follows: accurate to one decimal place.
Promulgated by the General Administration of Standards of the People's Republic of China in 1982-0510
Implemented on 1983-03-01
GB 3074.3-82
Oxidizability=
Where: W—oxidation weight loss of the sample in 4 hours, mg; G
—sample weight, g,
4 hours (oxidation time), h.
5.2 Test error
The error of two parallel tests shall not exceed 1.5 mg/g·h. Test report
The test report shall include the following contents:
Sample number, specification and source.
The half-mean value of the oxidizability of the sample at the same end. Additional Notes:
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by Jilin Carbon Plant. The main drafter of this standard is Cheng Jingzhi.
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