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This is Part 82 of GB/T 223.
This part was drafted in accordance with the rules given in the GB/T 1.1-2009.
This part replaces GB/T 223.82-2007 Steel and Iron — Determination of Hydrogen Content — Inert Gas Impulse Fusion Heat Conductivity Method in whole. The following technical deviations have been made with respect to the GB/T 223.82-2007 (the previous edition).
— modification of the standard name;
— modification of the measuring range;
— addition of the content of infrared detection;
— addition of ultrasonic cleaning, powder sample, chip sample and other contents;
— addition of single-point calibration and multi-point calibration in 7.3 Calibration;
— addition of “7 Analysis Procedure”; the original "5.2 Instrument preparation", "7 Calibration" and "8 Measurement" are all included in Clause 7;
— modification of the equations of repeatability limit and reproducibility limit in "9 Precision".
This part was proposed by the China Iron and Steel Association.
This part is under the jurisdiction of the National Technical Committee 183 on Iron and Steel of Standardization Administration of China (SAC/TC 183).
The previous editions of this part are as follows:
— GB/T 223.82-2007.
Steel and Iron — Determination of Hydrogen Content — Thermal Conductivity/Infrared Method after Fusion under Inert Gas
1 Scope
This part of GB/T 223 specifies a thermal conductivity/infrared method after fusion under inert gas for the determination of hydrogen content.
This part is applicable to the determination of hydrogen content in steel with a mass fraction of 0.6 μg/g to 30.0 μg/g.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 6379.1 Accuracy (Trueness and Precision) of Measurement Methods and Results — Part 1: General Principles and Definitions (GB/T 6379.1-2004, ISO 5725-1:1994, IDT)
GB/T 6379.2 Accuracy (Trueness and Precision) of Measurement Methods and Results — Part 2: Basic Method for the Determination of Repeatability and Reproducibility of a Standard Measurement Method (GB/T 6379.2-2004, ISO 5725-2:1994, IDT)
GB/T 20066 Steel and Iron — Sampling and Preparation of Samples for the Determination of Chemical Composition (GB/T 20066-2006, ISO 14284:1996, IDT)
3 Principle
The test portion is placed in a degassed graphite crucible and heated to melt in an inert atmosphere. Hydrogen in the test portion is released in the form of molecular and enters the carrier gas. After separation with other gaseous extracts by the chromatographic column, it is detected in the thermal conductimetric tank. Or hydrogen molecules carried by the air flow through hot copper oxide after conversion to water, tested in a specific infrared pool. The hydrogen content is calculated according to the change of thermal conductivity or infrared absorption intensity signal.
4 Reagents and Materials
4.1 High purity carrier gas, purity > 99.99%, can be argon, nitrogen or helium, as recommended by the instrument manufacturer.
4.2 Power gas, nitrogen, argon or compressed air, oil and water content less than 0.5%. Combustible gases are prohibited.
4.3 Carbon tetrachloride, acetone or ether, analytically pure.
4.4 Anhydrous magnesium perchlorate, granule reagent.
4.5 Molecular sieve, its property meets the test requirements.
4.6 Schutze reagent or linear copper oxide: Schutze reagent for thermal conductivity method and linear copper oxide for infrared method.
4.7 Graphite (electrode) crucible, disposable, made of high purity graphite.
4.8 Hydrogen reference material/standard sample in steel (iron).
5 Instruments
Inert gas fusion-thermal conductivity/infrared determination hydrogen analyzers, including pulsed graphite electrode furnaces, analytical gas stream impurity removal systems, auxiliary purification systems, and thermal conductivity cells or infrared cell hydrogen measurement systems.
6 Sampling and Sample Preparation
6.1 General Requirements
Sampling and sample preparation shall be carried out in accordance with GB/T 20066.
6.2 Sampling and preparation before furnace
A special sampling device shall be used for sampling before the furnace. Before a new sampling method or a new sampling device is used, its reliability and effectiveness shall be evaluated and an evaluation report shall be issued. If the sample obtained before furnace is stored for a long time (not more than 24 h), it can be directly stored in dry ice or liquid nitrogen after the sample is rapidly cooled, and the sample and container are transported or transferred together. For a short time (less than 1 h), it can be stored in a desiccator, using tweezers during operation and avoiding condensation on the surface of the sample.
Take out the sample from cryogenic storage and transportation container, remove the debris such as broken glass on the surface, and remove the dirty or porous part of the head; before the surface frosting is completed, the sample rod is directly put into the absolute ethanol, and taken out after a few minutes. Put it in carbon tetrachloride, acetone or ether. When the sample is restored to near room temperature, take it out and cut it into small pieces, then wash it with carbon tetrachloride, acetone or ether, and dry it as soon as possible.
6.3 Sampling and preparation from ingots or profiles
For forging or casting parts, it is recommended to use sawing, planing, wire cutting and other methods of sampling, not recommended to use water-welded open flame cutting.
Sample preparation can be done by lathe cutting, boring and grinding, and the surface finish is not strictly required. It is recommended to use a lathe cutting system and use ultrasonic cleaning to remove traces of grease and dirt from rough surfaces. The sample surface shall be free from any thick scales or wire cuts.
Cut a appropriate size column/strip samples with a mass of 0.1 g to 6 g, usually 0.5 g to 1.0 g, and soak them in containers containing carbon tetrachloride, acetone or ethyl ether; and put into ultrasonic cleaners with a power of 50 W to 100 W. After ultrasonic cleaning for about 3 min, the samples were taken out, and air-dried naturally or air-dried by cold air and then entered the analysis procedure. Pay attention to the cleanliness of the cleaning agent in the container and change it regularly.
Clean samples, such as hydrogen filled samples, are cleaned with carbon tetrachloride, acetone or ether, dried by air or air drying, and then used directly.
6.4 Powder sample
Powder samples need to be sampled from a large number of well-mixed powders. After sampling, it can be stored in a clean plastic self-sealing bag for a short time, and in a vacuum bag, argon bag and sealed glass bottle for a long time. Paper bag is not suitable for water and air permeability.
Powder samples are difficult to clean and need not sample preparation, and can be wrapped directly in nickel foil, tin foil or tin bag. Conduct analysis as soon as possible after weighing, and deduct the blank of nickel foil, tin foil or tin bag when calculating hydrogen content. The preparation of the powder sample is in accordance with the powder standard substance/standard sample used.
6.5 Chip sample
The chip samples taken from profiles or castings cannot be used as stationary hydrogen samples due to hydrogen transfer during processing.
6.6 Other samples
Take a sample of the original material of a different shape. The sampling operation can be processed by cutting, sawing, wire cutting, etc., and shall avoid overheating and pollution as much as possible. The wire material can be sampled directly.
Foreword II
1 Scope
2 Normative References
3 Principle
4 Reagents and Materials
5 Instruments
6 Sampling and Sample Preparation
7 Analytical Procedure
8 Result Calculation
9 Precision
10 Test Report
Annex A (Informative) Raw Data of Precision Test
