This standard specifies the method for measuring carbon content in nickel-chromium and nickel-chromium-iron alloys by coulometric method. This standard is applicable to the determination of carbon content in nickel-chromium and nickel-chromium-iron alloys. Determination range: 0.01% to 0.20%. JB/T 6326.9-1992 Chemical analysis method for nickel-chromium and nickel-chromium-iron alloys Coulometric method for determination of carbon content JB/T6326.9-1992 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T6326.9-1992bzxZ.net
Chemical analysis method for nickel-chromium and nickel-chromium-iron alloys-coulometric determination of carbon content
Published on June 26, 1992
Implementation of the Ministry of Machinery and Electronics Industry of the People's Republic of China on January 1, 1993
Mechanical Industry Standard of the People's Republic of China
Chemical analysis method for nickel-chromium and nickel-chromium-iron alloys-coulometric determination of carbon content
Subject content and scope of application
This standard specifies the method for determining the carbon content of nickel-chromium and nickel-chromium-iron alloys by coulometric method. This standard is applicable to the determination of carbon content in nickel-chromium and nickel-chromium-iron alloys. Determination range: 0.01%~0.20%. 2 Referenced standards
GB1467
General principles and general provisions for chemical analysis methods for metallurgical products. 3 Method Summary
JB/T6326.91992
The sample is burned at high temperature in an oxygen flow to oxidize carbon to generate carbon dioxide, which is then sent into a perchloric acid solution with a given pH value with oxygen as a carrier gas to be absorbed. At this time, the pH value of the solution changes. At the same time, a pulse current with a constant charge is used to electrolyze the absorption solution to restore it to its original pII value. The number of pulses is recorded by a counter, which is proportional to the amount of carbon, so that the carbon content in the sample can be calculated. 4 Reagents and Instruments
4.1 Perchloric acid lock,
4.2 Carbonic acid.
4.3 Sodium oxide.
4.4 Tin particles.
4.5 Reduced iron powder.
4.6 Isopropyl alcohol.
4.7 Silver nitrate solution (50g/1).
Absorption solution: weigh 25g perchloric acid (4.1) and dissolve it in 500ml water, add 10ml isopropanol (4.2), and mix well. 4.8
4.9 Anode solution: weigh 100g perchloric acid (4.1) and dissolve it in water, add 10g barium carbonate (4.2), transfer it into a 500ml volumetric flask, dilute it to the mark with water, and mix well.
4.10 Reference solution: weigh 5g perchloric acid (4.1) and 3g sodium chloride (4.3), dissolve them in 100ml water, add a few drops of silver nitrate solution (4.7). Heat to 60-70℃, cool and use the above clear solution. The precipitate does not need to be filtered out. Flux: tin granules (4.4) or tin granules (4.4) + reduced iron powder (4.6) (1+1). 4.11
Instrument: Coulometric carbon analyzer.
3 Analysis steps
5.1 Sample quantity
Weigh 0.500g of sample.
5.2 Blank test
Carry out a blank test together with the sample.
Approved by the Ministry of Machinery and Electronics Industry on June 26, 1992 and implemented on January 1, 1993
JB/T6326.91992
5.3.1 Pass oxygen and adjust its flow rate according to the instrument manual, turn on the power of the high-frequency induction furnace and preheat for 30 minutes, start the counter electrolysis switch, use the potentiometer to adjust the pH of the absorption liquid (4.8) to 9.0~9.5, and use the standard sample to verify that the instrument has reached the normal use state. Note: 1) If there is no commercial induction furnace for fixed carbon, a high-temperature tube furnace with a furnace temperature of 1250-1300C can be used instead. 5.3. 2
Place the sample in a crucible that has been burned at high temperature, add about 1g of flux (4.11), place the crucible into the combustion tube, press the oscillation switch
, the sample starts to burn, carbon dioxide is brought into the absorption cell, the pointer of the potentiometer deflects, and the measuring counter on the measuring unit is started at the same time.
The counter starts counting. After 3 minutes, the pointer of the potentiometer returns to zero, the counting stops, the analysis ends (the indicator light is on), and the value on the counter is read. 6
Calculation of analysis results
Calculate the percentage of carbon according to the following formula:
Where: A counter reading:
B--Blank test reading;
S--Instrument sensitivity (0.5×10*g); n-Sample amount g
Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table. Table
0.010~0.050
>0.050~0.100
>0.100~0.200
Additional Notes:
This standard is proposed and managed by Shanghai Electric Science Research Institute of the Ministry of Machinery and Electronics Industry. This standard was drafted by Shaanxi Iron and Steel Research Institute and Shanghai Electric Science Research Institute. The main drafters of this standard are Sun Shaoqing, An Qingfeng, Liu Kangmei and Huang Liuqing. Allowable difference
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