ISO 15355 pdf download

ISO 15355 pdf download.Steel and iron — Determination of chromium content — Indirect titration method 1 Scope This International Standard specifies a potentiometric titration method for the determination of chromium content in steel and iron. The method is applicable to chromium contents between 1 % (m/m) and 35 % (m/m). Vanadium contents in steel and iron should be less than 1 % (m/m) for chromium contents higher than 1 0 % (m/m) and less than 0,2 % ( m / m ) for chromium contents less than 1 0 % (m/m). 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 385-1 :1 984, Laboratory glassware — Burettes –– Part 1 : General requirements . ISO 648:1 977, Laboratory glassware — One-mark pipettes . ISO 1 042:1 998, Laboratory glassware — One-mark volumetric flasks . ISO 3696:1 987, Water for analytical laboratory use — Specification and test methods . ISO 4942:1 988, Steel and iron — Determination of vanadium content — N-BPHA spectrophotometric method . ISO 4947:1 986, Steel and cast iron — Determination of vanadium content — Potentiometric titration method . ISO 5725-1 :1 994, Accuracy (trueness and precision) of measurement methods and results — Part 1 : General principles and definitions . ISO 5725-2:1 994, 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 . ISO 5725-3:1 994, Accuracy (trueness and precision) of measurement methods and results 3 Principle Fusion of the sample with sodium peroxide followed by acidification with sulfuric acid. Oxidization of chromium (III) to dichromate with peroxodisulfate using silver as a catalyst. Reduction of the dichromate with an excess of a solid iron (II) salt and potentiometric back titration of the excess with a dichromate solution. Any interference from vanadium is corrected mathematically. 4.10 Ferroammonium disulfate, (NH 4 ) 2 Fe(SO 4 ) 2 6H 2 O The...