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This document is developed in accordance with the rules given in GB/T 1.1-2020 Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents.
This document has been redrafted and modified in relation to ISO/TR 17055:2002 Steel - Determination of silicon content - Inductively coupled plasma atomic emission spectrometric method.
The clause “Terms and definitions” is added in this document.
The technical differences with respect to ISO/TR 17055:2002 and their justifications are as follows:
——The range of determination in Clause 1 "Scope" is expanded to better meet the needs of the laboratory;
——The adjustments of technical deviations are made for the normative references in this document so as to adapt to the technical conditions of China. The adjustments are mainly reflected in Clause 2 "Normative references", with the specific adjustments as follows:
? ISO 5725-1:1994 is replaced by GB/T 6379.1 which is identical to the international standard (see 9.2);
? ISO 5725-2:1994 is replaced by GB/T 6379.2 which is identical to the international standard (see 9.2);
? ISO 3696:1987 is replaced by GB/T 6682 which is modified in relation to the international standard (see Clause 5);
? ISO 1042:1998 is replaced by GB/T 12806 which is not identical to the international standard (see 6.1);
? ISO 648:1977 is replaced by GB/T 12808 (see 6.1);
? ISO 14284:1996 is replaced by GB/T 20066 which is identical to the international standard (see Clause 7);
? ISO 5725-3:1994 is deleted (see 9.2).
——Concentrations of reagents and silicon stock solution used in Clause 5 are adjusted, and the method of preparing silicon stock solution with ammonium silicofluoride is added;
——Two recommended analytical lines are added in "6.2.2 Analytical lines” to provide more choices for operators;
——"6.2.5 Limit of detection (LOD) and limit of quantitation (LOQ)” is revised, and the "background equivalent concentration" in the international standard is replaced by "LOQ", which is consistent with the relevant international standards issued after 2004;
——"6.5 Pipettor" is added to ensure the accuracy in measuring the volume of standard solution;
——The calibration method in Clause 8 "Test procedure" is modified, and the calibration curve method is adopted to improve the operability of the standard;
——The control requirements for sample dissolution temperature is added in "8.3.1 Preparation of test sample solution" to ensure that the silicon does not volatilize during the dissolution of test sample solution;
——"9.2 Precision" is revised, and the precision test is reorganized to determine the precision, so as to meet the requirements of product quality control.
The following editorial changes have been made in this document:
——To be consistent with the existing standard series, the standard name is changed to Iron, steel and alloy - Determination of silicon content - Inductively coupled plasma atomic emission spectrometric method;
——Annex A (Normative) “Method for determining the performance criteria of apparatus” is added.
This document was proposed by China Iron and Steel Association.
This document is under the jurisdiction of the National Technical Committee on Iron and Steel of Standardization Administration of China (SAC/TC 183).
Iron, steel and alloy - Determination of silicon content - Inductively coupled plasma atomic emission spectrometric method
WARNING——Persons using this document shall be familiar with normal laboratory practice. This document does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions.
1 Scope
This document specifies a method for the determination of silicon contents by inductively coupled plasma atomic emission spectrometric method.
This document is applicable to the determination of silicon contents of mass fraction 0.01% to 5% in pig iron, cast iron, non-alloy steel, low-alloy steel and alloy steel.
2 Normative references
The following referenced documents are indispensable for the application of this standard. 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 6682 Water for analytical laboratory use - Specification and test methods (GB/T 6682-2008, ISO 3696:1987, MOD)
GB/T 12806 Laboratory glassware - One-mark volumetric flasks (GB/T 12806-2011, ISO 1042:1998, NEQ)
GB/T 12808 Laboratory glassware - One-mark pipettes
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)
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3 Terms and definitions
No terms and definitions are listed in this document.
4 Principle
The sample is dissolved in a hydrochloric, nitric and hydrofluoric acid mixture. If necessary, an internal standard element is added and the solution is diluted to known volume. After the solution is filtered (if necessary), it is nebulized into an ICP torch, and the emission intensity of the analytical spectral lines of silicon and that of the spectral lines of internal standard elements are measured.
5 Reagents and materials
During the analysis, unless otherwise stated, only reagents of recognized analytical grade and grade 2 water specified in GB/T 6682 are used.
5.1 High-purity iron, with silicon content not more than 0.001%.
5.2 Hydrofluoric acid, ρ about 1.15g/mL.
5.3 Hydrochloric acid, ρ about 1.19g/mL.
5.4 Nitric acid, ρ about 1.42g/mL.
5.5 Nitric acid, ρ about 1.42g/mL, diluted to 1+1.
5.6 Perchloric acid, ρ about 1.67g/mL.
5.7 Acid mixture, containing three portions of hydrochloric acid (5.3) and one portion of nitric acid (5.4).
5.8 Internal standard solution, 1,000μg/mL.
Choose a suitable element to be added as internal standard, prepare a 1,000μg/mL solution, and dilute it to appropriate concentration when in use.
5.9 Silicon stock solution, 500μg/mL.
Weigh, to the nearest 0.001g, 0.500g of high purity silicon (minimum 99.95% mass fraction) and put it in a 100mL PTFE beaker (6.3), add 5mL of water, slowly add a mixture of 30mL of hydrofluoric acid (5.2) and 3mL of nitric acid (5.4) without heating, and dissolve it in water bath at room temperature. Transfer the solution quantitatively to a 1,000mL polypropylene volumetric flask (6.4). Make up to the mark with water and mix. Ensure that the temperature is the same as that at which the volumetric flask is calibrated.
Or weigh 1.5858g of ammonium silicofluoride (minimum 99.99% mass fraction), put it in a 250mL PTFE beaker (6.3), add 100mL of water and 10mL of nitric acid (5.4) until it is completely dissolved, and then add, dropwise, 10mL of hydrofluoric acid (5.2), and transfer the solution to a 500mL polypropylene volumetric flask (6.4), and then make up to the mark with water and mix. Ensure that the temperature is the same as that at which the volumetric flask is calibrated.
This stock solution contains 500μg of silicon per 1mL.
5.10 Silicon standard solution, 100μg/mL.
Using a plastic pipette, transfer 50.0mL of the silicon stock solution (5.9) to a 250mL polypropylene volumetric flask (6.4). Add 5.0mL of hydrofluoric acid (5.2). Make up to the mark with water and mix. Ensure that the temperature is the same as that at which the volumetric flask is calibrated.
This standard solution contains 100μg of silicon per 1mL.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Reagents and materials
6 Apparatus
7 Sampling and preparation of samples
8 Test procedure
9 Test data processing
10 Test report
Annex A (Normative) Method for determining the performance criteria of apparatus
Annex B (Informative) Additional information on the precision test
Annex C (Informative) Graphical representation of precision data
