Overview
EN ISO 4829-2:2016 (CEN adoption of ISO 4829-2:2016) specifies a laboratory spectrophotometric method - the reduced molybdosilicate method - for the determination of total silicon in steels. It is intended for silicon mass fractions in the narrow range 0.01 % to 0.05 %. The standard defines the principle, required reagents and apparatus, sample dissolution and treatment, color development, spectrophotometric measurement and expression of results.
Key Topics
- Scope and applicability: Total silicon determination in steels with Si between 0.01 % and 0.05 % (mass fraction).
- Analytical principle: Dissolution of the test portion (acid attack), fusion of acid‑insoluble residue, formation of an oxidized molybdosilicate complex and selective chemical reduction to a blue complex measured spectrophotometrically (≈810 nm).
- Interference control: Use of oxalic acid and controlled sulphuric acid concentration to prevent interference from elements such as phosphorus, arsenic and vanadium.
- Reagents and contamination control: Use of analytical-grade reagents and ISO 3696 Grade 2 water (ion-exchange demineralized water is not permitted due to colloidal silica risk). Freshly prepared solutions and storage in polypropylene or PTFE containers are recommended to avoid contamination.
- Equipment and glassware: Standard laboratory volumetric apparatus (referenced ISO glassware standards) and spectrophotometer suitable for the specified wavelength.
- Calibration and results: Preparation of silicon standards and calibration curve procedures, plus instructions for expressing results and reporting. Precision and interlaboratory information are included in the standard.
Applications
- Quality control and acceptance testing of steel products where low silicon levels must be monitored (e.g., electrical steels, specialty alloys).
- Chemical analysis laboratories in steel mills and third‑party testing labs performing composition verification for specifications and certifications.
- R&D and process control teams monitoring melt chemistry, raw material qualification, and trace-level silicon effects on properties.
- Failure analysis and metallurgical investigations where accurate low-level silicon data are required.
Who Should Use This Standard
- Metallurgical and analytical chemists
- Steelworks laboratory personnel and quality managers
- Third‑party testing and certification bodies
- Material engineers and researchers working with low‑silicon steels
Related Standards
Keywords: EN ISO 4829-2:2016, silicon determination, reduced molybdosilicate spectrophotometric method, steel analysis, spectrophotometry, silicon 0.01–0.05%.
