GB/T 5059.7-1988 Chemical analysis method for ferromolybdenum - Determination of carbon content by infrared absorption method GB/T5059.7-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methods for chemical analysis of ferromolybdenum
Determination of carbon content by infrared absorption methodbZxz.net
Methods for chemical analysis of ferromolybdenumThe infrared absorption method for thedetermination of carbon contentThis standard is applicable to the determination of carbon content in ferromolybdenum. Determination range: 0.010%～0.400%. UDC 669.15'28
GB 5059.788
This standard complies with GB1467-78 "General Principles and General Provisions of Standards for Chemical Analysis Methods of Metallurgical Products" 1 Method Summary
The sample is heated and burned in the oxygen flow of a high-frequency induction furnace. The generated carbon dioxide is carried by oxygen to the measuring chamber of the infrared analyzer. Carbon dioxide absorbs infrared energy of a certain wavelength. Its absorption energy is proportional to its concentration. The carbon content can be measured according to the change in the energy received by the detector. 2 Reagents and materials
Acetone: The carbon content of the residue after evaporation is less than 0.0005%. 2.2
Magnesium perchlorate: anhydrous, granular.
Caustic soda asbestos: granular.
Glass wool.
Tungsten granules: carbon content less than 0.002%, particle size 0.8~1.4mm. Tin granules: carbon content less than 0.002%, particle size 0.4~0.8mm. If necessary, wash with acetone (2.1) and dry at room temperature. 2.6
Oxygen: purity greater than 99.95%, other grades of oxygen can also be used if a low and consistent blank can be obtained. Power gas source: nitrogen or compressed air, with impurities (water and oil) less than 0.5%. 2.9 Quality crucible: Φ×h, mm: 23×23 or 25×25, and burned in a high-temperature heating furnace above 1200℃ for 4h or burned with oxygen until the blank value is the lowest.
2.10 Crucible tongs.
3 Instruments and equipment
Infrared absorption carbon determination instrument (sensitivity is 1.0Ppm) 3.1
The device is shown in the figure.
3.1.1 Washing bottle (3): Contains caustic soda asbestos (2.3). 3.1.2 Drying tube (4, 9): Contains magnesium perchlorate (2.2). 3.2 Gas source
3.2.1 The carrier gas system includes an oxygen container, a two-stage pressure regulator and a timing control part to ensure the provision of appropriate pressure and rated flow. 3.2.2 The power gas source system includes power gas (nitrogen or compressed air), a two-stage pressure regulator and a timing control part to ensure the provision of appropriate pressure and rated flow.
Approved by the Ministry of Metallurgical Industry of the People's Republic of China on February 2, 1988 264
Implemented on March 1, 1989
GB5059.7-88
1-Oxygen cylinder; 2-Two-stage pressure regulator, 3-Gas washing bottle; 4.9-Drying tube; 5-Pressure regulator; 6-High-frequency induction furnace; 7 Combustion tube; 8-Dust collector, 10-Flow controller; 11-Converter for converting carbon oxide to carbon dioxide, 12 Desulfurizer; 13-Carbon dioxide infrared detector 3.3 High-frequency induction furnace
Should meet the requirements of the melting temperature of the sample.
3.4 ​​Control system
3.4.1 The microprocessor system includes a central processing unit, a memory, a keyboard input device, an information center display screen, an analysis result display screen and an analysis result printer, etc.
3.4.2 Control functions include automatic loading and furnace lifting, automatic cleaning, analysis condition selection and setting, analysis process monitoring and alarm interruption, analysis data collection, calculation, calibration and processing, etc. 3.5 Measurement system
It is mainly composed of an electronic balance (sensitivity not greater than 1.0mg) controlled by a microprocessor, an infrared analyzer and electronic measuring elements. 4 Sample
All samples should pass through a 0.125mm sieve.
5 Analysis steps
5.1 Sample quantity
Weigh 0.800~1.000g of sample.
5.2 Blank test
Weigh 0.800-1.000g of low-carbon (carbon content less than 50ppm) standard sample of the same type as the sample to be tested (if there is no standard sample of the same type, other steel standards with similar composition can be selected) and place it in a crucible (2.9) pre-filled with 0.300±0.005g tin particles (2.6), cover it with 1.500±0.005g tungsten particles (2.5), and measure it according to 5.5 on the same range or channel. Repeat enough times until a low and consistent reading is obtained. The blank value should be equal to the difference between the measured carbon content and the known carbon content of the standard sample. Record the minimum three readings, calculate the average value, and refer to the instrument manual to enter the average value into the analyzer. The instrument will then perform electronic compensation for the blank value when measuring the sample. 5.3 Analysis preparation
GB5059.7-88
5.3.1 Check and debug the instrument according to the instrument manual to ensure that the instrument is in a normal and stable state. 5.3.2 Select and set the best analysis conditions.
5.3.3 Use standard samples and flux to perform two test tests according to 5.5.1 and 5.5.2 to determine whether the instrument is normal. Weigh several portions of 1.000g of standard samples with a carbon content of about 0.05%, and measure them according to 5.5. The result fluctuation should be within the range of 5.3.4
±0.003%, otherwise the sensitivity of the instrument should be adjusted according to the instrument requirements. 5.4 Calibration test
5.4.1 According to the carbon content of the sample to be tested, select the corresponding range or channel, and select three standard samples of the same type (the carbon content of the sample to be tested should fall within the range of the carbon content of the selected three standard samples), and calibrate in turn. The fluctuation of the results should be within the allowable error range to confirm the linearity of the system, otherwise the linearity of the system should be adjusted according to the instrument manual. 5.4.2 Different ranges or channels should be measured and calibrated separately. 5.4.3 When the analysis conditions change, such as the instrument has not been preheated to 1h, the blank value of the oxygen source, crucible or flux has changed, it is required to re-measure the blank and calibrate.
5.5 Determination
5.5.1 According to the carbon content range of the sample to be tested, select the best analysis conditions of the instrument: such as the combustion integration time of the instrument, the setting conditions of the comparison level (or set number).
5.5.2 Place the weighed sample (5.1) in a crucible (2.9) pre-filled with 0.300g of tin particles (2.6), cover it with 1.500g of tungsten particles (2.5), take it with tongs and place it on the furnace base, operate according to the instrument manual, start analysis and read the results. 6 Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table. %
>0.025~0. 070
>0.070-0.120
>0. 120-0. 400
Additional remarks:
This standard was drafted by Jilin Ferroalloy Factory.
The main drafter of this standard is Chang Yanfu.
Allowance
From the date of implementation of this standard, the former Ministry of Metallurgical Industry Standard YB580-65 "Chemical Analysis Method of Ferromolybdenum" shall be invalid.
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