SIST EN ISO 7526:2020

SLOVENSKI STANDARD
SIST EN ISO 7526:2020
01-junij-2020
Nadomešča:
SIST EN 27526:2009
Feronikelj - Določevanje žvepla - Metoda z infrardečo absorpcijo po zgorevanju v
indukcijski peči (ISO 7526:2020)
Ferronickels - Determination of sulfur content - Infrared absorption method after
induction furnace combustion (ISO 7526:2020)
Ferronickel - Bestimmung des Schwefelgehalts - Infrarot-Absorptionsverfahren nach der
Verbrennung im Induktionsofen [Routineverfahren] (ISO 7526:2020)
Ferronickels - Détermination de la teneur en soufre - Méthode par absorption dans
l'infrarouge après combustion dans un four à induction (ISO 7526:2020)
Ta slovenski standard je istoveten z: EN ISO 7526:2020
ICS:
77.120.40 Nikelj, krom in njune zlitine Nickel, chromium and their
alloys
SIST EN ISO 7526:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 7526:2020

---------------------- Page: 2 ----------------------
SIST EN ISO 7526:2020


EN ISO 7526
EUROPEAN STANDARD

NORME EUROPÉENNE

March 2020
EUROPÄISCHE NORM
ICS 77.100; 77.120.40 Supersedes EN 27526:1991
English Version

Ferronickels - Determination of sulfur content - Infrared
absorption method after induction furnace combustion
(ISO 7526:2020)
Ferronickels - Détermination de la teneur en soufre - Ferronickel - Bestimmung des Schwefelgehalts -
Méthode par absorption dans l'infrarouge après Infrarot-Absorptionsverfahren nach der Verbrennung
combustion dans un four à induction (ISO 7526:2020) im Induktionsofen [Routineverfahren] (ISO
7526:2020)
This European Standard was approved by CEN on 15 November 2019.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7526:2020 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------
SIST EN ISO 7526:2020
EN ISO 7526:2020 (E)
Contents Page
European foreword . 3

2

---------------------- Page: 4 ----------------------
SIST EN ISO 7526:2020
EN ISO 7526:2020 (E)
European foreword
This document (EN ISO 7526:2020) has been prepared by Technical Committee ISO/TC 155 "Nickel and
nickel alloys" in collaboration with Technical Committee CEN/SS M14 “Nickel” the secretariat of which
is held by CCMC.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by September 2020, and conflicting national standards
shall be withdrawn at the latest by September 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 27526:1991.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 7526:2020 has been approved by CEN as EN ISO 7526:2020 without any modification.

3

---------------------- Page: 5 ----------------------
SIST EN ISO 7526:2020

---------------------- Page: 6 ----------------------
SIST EN ISO 7526:2020
INTERNATIONAL ISO
STANDARD 7526
Second edition
2020-03
Ferronickels — Determination of
sulfur content — Infrared absorption
method after induction furnace
combustion
Ferronickels — Détermination de la teneur en soufre — Méthode
par absorption dans l'infrarouge après combustion dans un four à
induction
Reference number
ISO 7526:2020(E)
©
ISO 2020

---------------------- Page: 7 ----------------------
SIST EN ISO 7526:2020
ISO 7526:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

---------------------- Page: 8 ----------------------
SIST EN ISO 7526:2020
ISO 7526:2020(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 1
6 Apparatus . 2
7 Sampling and sample preparation . 3
8 Procedure. 4
8.1 Preparing and stabilizing the instrument . 4
8.2 Blank test and zero adjustment . 4
8.2.1 Sulfur contents ≤ 0,05 % . 4
8.2.2 Sulfur contents > 0,05 % . 4
8.3 Calibration . 4
8.4 Determination . 5
9 Expression of results . 6
9.1 Calculation . 6
9.2 Precision . 6
10 Test report . 8
Annex A (informative) Features of commercial high frequency induction furnaces and
infrared sulfur analysers . 9
Annex B (informative) Composition of the samples used for the validation precision test .10
Annex C (informative) Graphical representation of the precision data .11
Bibliography .12
© ISO 2020 – All rights reserved iii

---------------------- Page: 9 ----------------------
SIST EN ISO 7526:2020
ISO 7526:2020(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 155, Nickel and nickel alloys, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/
SS M14, Nickel, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 7526:1985), which has been technically
revised. The main changes compared with the previous edition are as follows:
— the scope has been limited to ferronickels only;
— the former Clauses 5 and 7 have been technically revised;
— the former Annexes A and C have been deleted;
— the precision data have been updated.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

---------------------- Page: 10 ----------------------
SIST EN ISO 7526:2020
INTERNATIONAL STANDARD ISO 7526:2020(E)
Ferronickels — Determination of sulfur content — Infrared
absorption method after induction furnace combustion
1 Scope
This document specifies an infrared absorption method after combustion in an induction furnace for
the determination of the sulfur content in ferronickels in the range of 0,002 % to 0,12 %.
The method is applicable to normal production operations. It uses commercially available equipment,
which is calibrated using steel and/or ferronickel certified reference materials (CRMs).
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Principle
Combustion of a test portion in a high-frequency induction furnace at high temperature in a current of
pure oxygen, and in the presence of accelerators and fluxes.
Transformation of sulfur into sulfur dioxide.
Measurement by infrared absorption of the sulfur dioxide carried by the current of oxygen.
5 Reagents
During the analysis, use only reagents of recognized analytical grade.
5.1 Oxygen, high purity (mass fraction minimum 99,5 %).
An oxidation catalyst [copper(II) oxide or platinum] tube heated at 600 °C, followed by appropriate
carbon dioxide and water absorbents, shall be used when the presence of organic contaminants is
suspected in the oxygen.
5.2 Inert ceramic (attapulgus clay), impregnated with sodium hydroxide and having particle sizes
from 0,7 mm to 1,2 mm for the absorption of carbon dioxide.
5.3 Magnesium perchlorate [Mg(ClO ) ], having particle size from 0,7 mm to 1,2 mm for the
4 2
absorption of moisture.
© ISO 2020 – All rights reserved 1

---------------------- Page: 11 ----------------------
SIST EN ISO 7526:2020
ISO 7526:2020(E)

5.4 Glass-wool.
5.5 Fluxes and accelerators.
5.5.1 General
A flux addition has the effect of bonding together small particles for more effective furnace coupling
and it helps to produce a more fluid melt.
An accelerator addition allows:
a) a good coupling medium for the induction heating of otherwise unsatisfactory samples (finely
divided samples, materials of complex composition);
b) a higher combustion temperature;
c) an increase of the mass of material in the crucible when the test portions are small.
Any flux or accelerator shall have low sulfur content and shall be used in the calibration procedure. The
total blank from all sources (oxygen, refractories, flux and accelerator) shall not exceed 0,000 5 % (mass
fraction) sulfur.
Some materials act as both a flux and an accelerator.
5.5.2 Fluxes
Common fluxes are tin, copper plus tin, copper or vanadium pentoxide.
5.5.3 Accelerators
Common accelerators are copper, iron, tungsten or nickel.
5.6 Steel and/or ferronickel certified reference materials (CRMs), containing from 0,001 % to
0,15 % (mass fraction) sulfur.
All reference materials used for calibration shall be certified by internationally recognized bodies.
Preference shall be given to materials that are certified using referee methods, e.g. ISO 4934, ISO 4935,
ISO 10701 and ISO 13902, traceable to SI units as opposed to those based on other certified reference
materials.
6 Apparatus
Usual laboratory apparatus and, in particular, the following.
6.1 Sulfur analyser.
6.1.1 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. A pressure regulator is
required to control the oxygen pressure to the furnace according to the manufacturer’s specification.
6.1.2 Purify the oxygen supply using tubes packed with inert ceramic (5.2) and magnesium perchlorate
(5.3) and maintain a flow rate of about 0,5 l/min while on stand-by.
2 © ISO 2020 – All rights reserved

---------------------- Page: 12 ----------------------
SIST EN ISO 7526:2020
ISO 7526:2020(E)

6.1.3 Maintain a glass-wool filter (5.4) between the furnace chamber and the analyser and change as
necessary. The furnace chamber, pedestal post and filter trap should be cleaned frequently to remove
oxide residues.
6.1.4 The manufacturer may recommend setting the programming unit to give a pre-burn period
before oxygen enters the furnace chamber. The test portion should be at a red heat during the pre-burn
period. When oxygen is introduced for the combustion stage, the temperatu
...