GB/T 14265-2017 PDF English (GB/T 14265-1993: Older version)
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General rule of chemical analysis for hydrogen, oxygen, nitrogen, carbon and sulfur in metallic materials
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General rule of chemical analysis for hydrogen, oxygen, nitrogen, carbon and sulfur in metalmaterials
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PDF Preview: GB/T 14265-2017
GB/T 14265-2017: PDF in English (GBT 14265-2017) GB/T 14265-2017
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.040.30
H 10
Replacing GB/T 14265-1993
General Rule of Chemical Analysis for Hydrogen, Oxygen,
Nitrogen, Carbon and Sulfur in Metallic Materials
ISSUED ON: OCTOBER 14, 2017
IMPLEMENTED ON: MAY 1, 2018
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the People’s Republic of China;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Terms and Definitions ... 5
4 Basic Principles ... 8
5 Instruments, Equipment and Devices ... 11
6 Sample ... 13
7 Determination of Test Conditions ... 13
8 Precision ... 15
General Rule of Chemical Analysis for Hydrogen, Oxygen,
Nitrogen, Carbon and Sulfur in Metallic Materials
1 Scope
This Standard specifies the requirements and general stipulations of the determination of
hydrogen, oxygen, nitrogen, carbon and sulfur in metallic materials through the method of gas
analysis.
This Standard is applicable to the formulation (revision) of national standards, industry
standards, group standards and enterprise standards on the analysis methods for hydrogen,
oxygen, nitrogen, carbon and sulfur in metallic materials.
2 Normative References
The following documents are indispensable to the application of this document. In terms of
references with a specified date, only versions with a specified date are applicable to this
document. In terms of references without a specified date, the latest version (including all the
modifications) is applicable to this document.
GB/T 6379 (all parts) Accuracy (trueness and precision) of Measurement Methods and Results
GB/T 8170 Rules of Rounding off for Numerical Values & Expression and Judgement of
Limiting Values
GB/T 17433 Foundation Terms for Chemical Analysis of Metallurgical Products
GB/T 20001.4-2015 Rules for Drafting Standards - Part 4: Test Method Standards
GB/T 27476.5 Safety in Testing Laboratories - Part 5: Chemical Aspects
3 Terms and Definitions
What is defined in GB/T 17433, and the following terms and definitions are applicable to this
document.
3.1 reduction (reducing) fusion
Reduction (reducing) fusion is a method, through which, the sample is fused at high
temperatures in a graphite crucible, in which, oxygen is reduced to carbon monoxide or carbon
dioxide by carbon, and hydrogen and nitrogen are precipitated in molecular state.
3.2 vacuum fusion extraction
Vacuum fusion extraction is a method, through which, the sample is fused at high temperatures
in the vacuum system, and the precipitated gas is collected.
3.3 inert gas fusion extraction
Inert gas fusion extraction refers to a method, through which, the sample is fused at high
temperatures in inert gas, and the precipitated gas is loaded into the analysis system by carrier
gas.
3.4 hot extraction
Hot extraction refers to a method, through which, the sample is heated in the system, and the
gas to be tested is extracted below the fusion point.
3.5 hydrogen reduction method
Hydrogen reduction method is a method, through which, the sample is heated at high
temperatures in the hydrogen flow, and the element to be tested is reduced to a gaseous
substance by hydrogen.
3.6 oxidation fusion method
Oxidation fusion method is a method, through which, the sample is fused at high temperatures
under the existence of oxidants, and the element to be tested is oxidized into a gaseous substance.
3.7 combustion method
Combustion method is a method, through which, the sample is fused at high temperatures in
the oxygen flow, and carbon, sulfur and hydrogen are respectively oxidized into carbon dioxide,
sulfur dioxide and water vapor, and loaded into the analysis system.
3.8 impulse fusion method
Impulse fusion method is a method, through which, the method is placed in a graphite crucible
between the two poles of an electrode furnace, and low-voltage large AC is added to facilitate
fast and high-temperature fusion.
NOTE: including vacuum impulse fusion and inert gas impulse fusion.
3.9 flux
Flux is a substance that can reduce the melting point of the sample and accelerate reactions at
high temperatures, so that the element to be tested quickly precipitates in a gaseous state.
3.10 inhibitor
Inhibitor is a substance that can inhibit volatilization, loosen melts, accelerate reactions and
reduce adsorption at high temperatures, so that the gas to be tested quantitatively precipitates.
3.11 bath
In proportion, add one or several metals in the crucible for melting bath in advance.
3.12 total hydrogen
Total hydrogen refers to the sum of hydrogen existing in various forms in metallic materials.
3.13 total oxygen
Total oxygen refers to the sum of oxygen existing in various forms in metallic materials.
3.14 total carbon
Total carbon refers to the sum of carbon existing in various forms in metallic materials.
3.15 total carbon in surface; surface carbon
Total carbon in surface / surface carbon refers to the sum of carbon on the metal surface.
3.16 dissolved hydrogen
Dissolved hydrogen refers to hydrogen existing in the form of solid solution in metal.
3.17 adsorbed oxygen
Adsorbed oxygen refers to oxygen absorbed on the metal surface.
3.18 free carbon; uncombined carbon
Free carbon / uncombined carbon refers to carbon existing in the uncombined state in metal.
3.19 hydrogen combined
Hydrogen combined refers to hydrogen existing in the combined state in metal.
3.20 carbon combined
Carbon combined refers to carbon existing in the combined state in metal.
3.21 diffusible hydrogen
Diffusible hydrogen refers to hydrogen diffused under normal conditions, in a closed device
and within a certain period of time.
3.22 precision
Precision refers to the consistency among independent test results under the specified
4.1.2 The sample is fused at high temperatures under a flux and oxygen flow (or under the
existence of oxidants); carbon, sulfur, hydrogen and nitrogen, which respectively form carbon
dioxide, sulfur dioxide, water vapor and nitrogen oxides, are quantitatively precipitated and
loaded into the analysis system.
4.1.3 The sample is in a graphite crucible, subject to vacuum fusion or inert gas fusion. Different
forms of oxides and nitrides are respectively released at different temperatures selected by the
instrumental programmed heating; oxygen is reduced into carbon monoxide or carbon dioxide
by carbon; nitrogen, which forms a molecular state, is quantitatively precipitated and loaded
into the analysis system through vacuum extraction or inert gas.
4.2 Detection Principle
4.2.1 Constant-volume manometric method
The extracted mixed gas is subject to physical separation or stepwise oxidation separation, and
the partial pressure of each component is measured with a Mcleod vacuum gauge. In accordance
with the equation of gas state, calculate the content of the element to be tested.
4.2.2 Thermal conductivity method
The extracted mixed gas is subject to selective partial absorption or separation, then loaded into
the thermal conductivity cell detector by carrier gas. Due to the different thermal conductivity
coefficients of different gases, the electrical signals (voltage values) given by the thermal
conductivity cell are different; the concentration of the gas element to be tested is directly
proportional to the variation of the electrical signals, and accordingly, calculate the content of
the gas element to be tested.
4.2.3 Infrared absorption method
Extract the mixed gas containing hydrogen, carbon monoxide and nitrogen (or convert the
hydrogen into water and carbon monoxide into carbon dioxide) and load it into the infrared
detector by carrier gas. The light intensity changes because the gas to be tested can absorb
infrared light of a specific wavelength. In accordance with the Lambert-Beer’s Law, calculate
the content of the gas element to be tested.
4.2.4 Coulometric method
The extracted carbon dioxide or sulfur dioxide is loaded into a solution with a pre-set pH value
for absorption by carrier gas. The pH value of the solution varies with the amount of carbon
dioxide or sulfur dioxide absorbed. Use electrolysis to restore the original pH value, and the
electricity consumed by electrolysis is directly proportional to the concentration of the absorbed
gas. In accordance with Faraday’s Laws of electrolysis, calculate the content of the element to
be tested.
4.2.5 Conductivity method
The extracted carbon dioxide or sulfur dioxide is respectively loaded into the conductivity cell
containing the corresponding absorption liquid for absorption, causing the conductivity of the
absorption liquid to change. In accordance with the change in conductivity, which is directly
proportional to the amount of gas absorbed, calculate the content of the element to be tested.
4.2.6 Time-of-flight mass spectrometry
The extracted mixed gas is loaded into the time-of-flight mass spectrometry detector by carrier
gas. Due to the different ion flight times of different mass numbers separated from the mixed
gas, in accordance with the positions and intensities of the mass spectrum peaks of different
ions separated, conduct a qualitative and quantitative analysis on the gas element to be tested
in the sample.
4.3 Principle of Chemical Method Determination
4.3.1 Chemical method for nitrogen determination
The sample is decomposed with acid, the nitride is converted into soluble ammonium salt,
which is heated and distilled in a strong alkali solution and precipitated as ammonia gas, loaded
into the absorption solution for absorption. Then, adopt the titration method or
spectrophotometry to conduct the determination and calculate the nitrogen content.
4.3.2 Chemical method for carbon determination
4.3.2.1 The sample is decomposed with acid, the combined carbon forms gaseous carbides and
precipitates; the free carbon does not react with acid. Through filtration and separation, adopt
the combustion method to determination the content of free carbon.
4.3.2.2 The sample is oxidized and fused in a high-temperature oxygen flow, and the carbon is
precipitated as carbon dioxide and loaded into an alkaline solution or an alkaline non-aqueous
solution for absorption. By measuring the gas volume change before and after the absorption
or the consumption of the non-aqueous solution, obtain the total carbon content.
4.3.3 Chemical method for sulfur determination
4.3.3.1 The sample is oxidized and fused at high temperatures, and the sulfur is precipitated as
sulfur dioxide and loaded into an absorption liquid (for example, iodine solution) for absorption.
Adopt the acid-base titration method, spectrophotometry or conductivity method to conduct the
determination and calculate the sulfur content.
4.3.3.2 The sample is dissolved with a strong acid under the existence of a strong oxidant, and
the sulfur forms SO24 . The test solution is separated by active alumina chromatography, and the
SO24 is retained in the column, eluted with ammonia water. Adopt the barium sulfate mass
method to conduct the determination and calculate the sulfur content.
4.3.3.3 The sample is dissolved with a strong acid under the existence of a strong oxidant, and
the sulfur forms SO24 . Through reduction and distillation, precipitate hydrogen sulfide gas,
The joints of each component are sealed with high-vacuum silicone grease.
5.2.3.2 The inert gas carrying the gas to be tested needs to be purified. The purifiers are
composed of desiccants, oxidants and adsorbents, etc. For devices with negative pressure load
delivery, the suction pump needs to maintain a stable pumping rate.
5.2.3.3 The graphite crucibles, graphite funnels and graphite powder (with a particle size of
0.104 mm ~ 0.124 mm) used for the extraction of hydrogen, oxygen and nitrogen elements for
analysis shall be made of spectrally pure or high-purity graphite materials.
5.2.3.4 The ceramic crucibles used for the extraction of carbon and sulfur elements for analysis
need to be baked at a high temperature before use.
5.2.4 Separation device
The separation device generally includes filters, oxidizers, condensers, absorbers and
chromatographic separation columns. Each component shall be able to efficiently separate the
analyte components.
5.2.5 Measuring devices
5.2.5.1 Commonly used detectors include thermal conductivity cell detector (TCD), infrared
absorption detector and time-of-flight mass spectrometry detector, etc. The detection sensitivity
and stability of the detectors shall comply with the requirements of the instruction manual and
relevant analysis methods. Electronic circuit components shall have a relatively wide linear
range and gain adjustment.
5.2.5.2 The detector of the constant-volume manometric method is Mcleod vacuum gauge
(referred to as Mcleod gauge for short). The measurement range shall satisfy the analysis
requirements, and the measurement volume shall be not less than 300 mL.
5.2.5.3 The conductivity measuring device is composed of conductivity cell, platinum electrode
pair and electronic circuit. The conductivity cell shall be placed in a constant-temperature bath,
and the temperature difference shall be within 1 C. Platinum electrodes coated with platinum
black shall be selected, and the distance between platinum electrodes cannot be arbitrarily
changed. The operating frequency of the power supply shall be adjusted in accordance with the
range specified in the instruction manual.
5.2.5.4 The Coulomb measuring device is composed of electrolytic cell, glass electrode,
reference electrode, platinum electrolytic electrode pair and electronic circuit, etc. Its technical
conditions shall comply with the stipulations of the instruction manual.
5.3 Instruments and Equipment Installation Site
5.3.1 High-frequency equipment and electrode furnace equipment shall be installed on a
workbench that is more than 1 m away from the wall, and ground wires shall be separately
buried; high-frequency equipment shall have shielding measures. The extraction device and
measuring device shall be separately powered.
5.3.2 The measuring instrument is required to be installed on a workbench with little vibration,
and there shall be no strong electromagnetic field around it.
5.3.3 For equipment that integrates the extraction device and measuring device, respective
power supply from external power sources is not required, and the others shall satisfy the
requirements of 5.3.1 and 5.3.2.
6 Sample
6.1 General Requirements
The stipulations of 6.8 in GB/T 20001.4-2015 shall be followed.
6.2 Shape
In accordance with the nature of laboratory samples, sample processing methods and measures
of preventing oxidation, hydrogen loss and contamination shall be formulated. In accordance
with the analysis requirements, process them into appropriate shapes and sizes. Generally, the
instrumental analysis samples of hydrogen, oxygen and nitrogen are blocky, clubbed or
columnar; the analysis samples of carbon and sulfur and the chemical method analysis samples
of nitrogen are in the form of uniform debris or powder, and also in the form of uniform small
blocks.
6.3 Pre-treatment
In accordance with the nature of the samples, analysis requirements and content range, perform
reagent cleaning or chemical surface corrosion treatment, rinsing and drying. For low-content
samples, surface treatment must be carried out. For the instrumental analysis powder samples
of hydrogen, oxygen and nitrogen, use platinum foil, nickel foil, tin foil, nickel capsule or tin
capsule to wrap them.
6.4 Storage
The treated samples shall be stored in ground glass bottles and placed in a dark and low-
temperature dry place. If the samples are stored for a long time, then, the container shall be
filled with dry inert gas or vacuum sealed.
7 Determination of Test Conditions
7.1 Preparation before Test
7.1.1 Preparation of instruments
7.1.1.1 Power on the high-frequency generator, and the warm-up time is not less than 15 min.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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