ISO 4934:2003

Overview

ISO 4934:2003 - Steel and iron - Determination of sulfur content - Gravimetric method specifies a laboratory gravimetric procedure for accurately measuring sulfur content in steels and iron (excluding steels containing selenium). The method is designed as a reference method suitable for standardizing samples and establishing certified reference values. Applicable sulfur range: 0.003 % to 0.35 % (mass fraction). Key elements include chemical dissolution, chromatographic separation, and gravimetric precipitation and weighing of sulfate as barium sulfate.

Key Topics

• Scope and limitations
  • Applicable to steels and iron, excluding selenium-containing steels.
  • Recommended as a reference method for certified material standardization.
• Analytical principle
  • Dissolution of test portion in dilute nitric acid with bromine or in nitric/hydrochloric acid (aqua regia) with bromine.
  • Oxidative treatment with perchloric acid and removal of interfering dehydrated oxides.
  • Addition of a measured sulfate spike to aid quantitation.
  • Chromatographic adsorption on an alumina column to separate sulfate from matrix interferences; elution with ammonium hydroxide.
  • Precipitation of sulfate as barium sulfate, followed by filtering, washing, ignition (heating) and gravimetric weighing.
• Reagents and apparatus
  • Use of analytical-grade reagents and grade 2 water (ISO 3696).
  • Specific items include an Allihn condenser, alumina-packed adsorption column, analytical balance and standard glassware.
• Sampling and test portion
  • Sampling and sample preparation in accordance with ISO 14284.
  • Test portion mass chosen according to expected sulfur content to meet method range and sensitivity.
• Quality and precision
  • The standard references ISO 5725 series for method accuracy, repeatability and reproducibility.

Applications

• Laboratories and national metrology institutes using ISO 4934:2003 for certified reference material preparation and interlaboratory comparisons.
• Industrial quality-control and materials testing in steel production, foundries and metallurgy labs where accurate sulfur determination is required for specification compliance.
• Regulatory and compliance testing where traceable, gravimetric sulfur analysis is needed for product certification, failure analysis or material qualification.

Related Standards

• ISO 14284 - Sampling and preparation of samples for chemical composition
• ISO 3696 - Water for analytical laboratory use
• ISO 565 - Test sieves (alumina particle sizing)
• ISO 5725 (Parts 1–3) - Accuracy (trueness and precision) of measurement methods

Keywords: ISO 4934:2003, sulfur content determination, gravimetric method, steel sulfur analysis, chromatographic separation, barium sulfate precipitation, reference method.