ISO 4935:1989 pdf download.Steel and iron一Determination of sulfur content一infrared absorption method after combustion in an induction furnace
1 Scope
ISO 4935:1989 pdf download specifies an infrared absorption method after combustion in an induction furnace for the determination of sulfur content in steel and iron.
The method Is applicable to sulfur contents between 0,002 % (rn/rn) and 0.10 % (ni/rn)
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards.
ISO 377: 1985, Wrought steel —- Selection and preparation of samples and test pieces.
ISO 3851 : 1984, Laboratoiy glassware — Burettes — Part 1. General requirements.
ISO 648: 1977, Laboratoy glassware — One-mark pip ettes. ISO 1042: 1983, Laboratoiy glassware — One-mark volumetric f/asks.
ISO 5725: 1986, Precision of test methods — Determination of repeatability and reproducibility for a standard test method by Inter-laboratory tests.
3 Principle
Combustion of a test portion with accelerator at a high temperature in a high-frequency Induction furnace in a current of pure oxygen. Transformation of sulfur into sulfur dioxide.
Measurement by infrared absorption of the sulfur dioxide carried by a current of oxygen.
4 Reagents and materials
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity.
4.1 Oxygen, 99,5 % (m/m) minimum.
An oxidation catalyst [copper(I) oxide or platinum] tube heated to a temperature above 450 °C must be used prior to a purify-ing unit (see annex C), when the presence of organic con-taminants is suspected in the oxygen.
4.2 Pure iron, of known low sulfur contents less than 0,000 5 % (m/m).
4.3 Suitable solvent, appropriate for washing greasy or dirty test samples, for example, acetone.
4.4 Magnesium perchlorate [Mg(CI04)2, particle size:from 0,7 mm to 1,2 mm.
4.5 Accelerator, tungsten, free of sulfur, or of known sulfur contents less than 0,000 5 % (m/m). The mesh size of the ac-celerator may be dependent on the type of apparatus used.
5 Apparatus
During the analysis, unless otherwise stated, use only ordinary laboratory apparatus.
All volumetric glassware shall be class A, in accordance with ISO 385-1, ISO 648 or ISO 1042 as appropriate.
The apparatus required for combustion in a high-frequency induction furnace and the subsequent infrared absorption measurement of the evolved sulfur dioxide may be obtained commercially from a number of manufacturers. Follow the manufacturer's instructions for the operation of the equipment.
Features of commercial instruments are given in annex C.ISO 4935 pdf download.