ISO 4968:2022
(Main)Steel — Macrographic examination by sulphur print (Baumann method)
Steel — Macrographic examination by sulphur print (Baumann method)
This document specifies a method (Baumann) for the macrographic examination of steel by means of contact printing using silver salts and acid. The method is applicable to steels of which the sulphur content is less than 0,40 %. This method can also be applied to cast irons.
Acier — Examen macrographique par empreinte au soufre (méthode Baumann)
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INTERNATIONAL ISO
STANDARD 4968
Second edition
2022-03
Steel — Macrographic examination by
sulphur print (Baumann method)
Reference number
ISO 4968:2022(E)
© ISO 2022
---------------------- Page: 1 ----------------------
ISO 4968:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 4968:2022(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General . 1
5 Principle and aim of the test .1
6 Test paper and reagents . 2
6.1 Photographic paper . 2
6.2 Reagents . 2
7 Fixing solution .2
8 Test piece . 3
9 Sampling . 3
10 Machining . 3
11 Procedure . 3
12 Test report . 4
Annex A (informative) Classification of sulphur print test results . 5
iii
© ISO 2022 – All rights reserved
---------------------- Page: 3 ----------------------
ISO 4968:2022(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 17, Steel, Subcommittee SC 7, Methods of
testing (other than mechanical tests and chemical analysis).
This second edition cancels and replaces the first edition (ISO 4968:1979), which has been technically
revised.
The main changes are as follows:
— in the Scope, the applicable steels for this method are specified as from 0,005 % to 0,40 %, and this
method may also be applied to cast irons;
— type and concentration of recommended reagents have been explicitly specified for steels with
different sulphur content, respectively, to improve test effect and efficiency;
— method to remove extra acid solution and bubbles, and method to drain have been added in detail;
— classification of test results as positive segregation, negative segregation and central segregation,
with examples in Annex, has been added.
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 2022 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 4968:2022(E)
Steel — Macrographic examination by sulphur print
(Baumann method)
1 Scope
This document specifies a method (Baumann) for the macrographic examination of steel by means of
contact printing using silver salts and acid.
The method is applicable to steels of which the sulphur content is less than 0,40 %. This method can
also be applied to cast irons.
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 terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 General
4.1 The sulphur print test is essentially a qualitative test. It is inadvisable to evaluate the sulphur
content of a given steel merely on the basis of its sulphur print.
4.2 Experience shows that the degree of darkening of the photo-sensitive emulsion is not always
in proportion to the quantity of sulphides present in the metal. Certain factors may influence the
macrographic attack to a greater or lesser extent; as examples, the following may be quoted:
— the chemical composition of the steel: the presence of certain elements modifies the type and shape
of the sulphides and consequently the appearance of the image obtained, for example concentrations
of titanium greater than 0,1 % give prints which do not reveal sulphides;
— the surface condition of the sample: the presence of surface cold working may alter the image
obtained;
— the sensitivity of the photographic paper.
4.3 The use of the test, and the conditions for interpreting the results observed, depend on the
particular case: details are laid down in product standards or shall be subject to special agreement.
5 Principle and aim of the test
5.1 The aim of macrographic examination by sulphur printing is to detect, by printing on photo-
sensitive papers previously soaked in acid, the position of areas containing sulphur inclusions found
1
© ISO 2022 – All rights reserved
---------------------- Page: 5 ----------------------
ISO 4968:2022(E)
in the metal in various chemical forms and with
...
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 4968
ISO/TC 17/SC 7
Steel — Macrographic examination by
Secretariat: AFNOR
sulfur print (Baumann method)
Voting begins on:
2021-12-20
Acier — Examen macrographique par empreinte au soufre (méthode
Baumann)
Voting terminates on:
2022-02-14
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 4968:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO 2021
---------------------- Page: 1 ----------------------
ISO/FDIS 4968:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 4968:2021(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General . 1
5 Principle and aim of the test .1
6 Test paper and reagents . 2
6.1 Photographic paper . 2
6.2 Reagents . 2
7 Fixing solution .2
8 Test piece . 2
9 Sampling . 3
10 Machining . 3
11 Procedure . 3
12 Test report . 4
Annex A (informative) Classification of sulphur print test results . 5
iii
© ISO 2021 – All rights reserved
---------------------- Page: 3 ----------------------
ISO/FDIS 4968:2021(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 17, Steel, Subcommittee SC 7, Methods of
testing (other than mechanical tests and chemical analysis).
This second edition cancels and replaces the first edition (ISO 4968:1979), which has been technically
revised.
The main changes are as follows:
— in the Scope, the applicable steels for this method are specified as from 0,005 % to 0,40 %, and this
method may also be applied to cast irons;
— type and concentration of recommended reagents have been explicitly specified for steels with
different sulphur content, respectively, to improve test effect and efficiency;
— method to remove extra acid solution and bubbles, and method to drain have been added in detail;
— classification of test results as positive segregation, negative segregation and central segregation,
with examples in Annex, has been added.
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 2021 – All rights reserved
---------------------- Page: 4 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 4968:2021(E)
Steel — Macrographic examination by sulfur print
(Baumann method)
1 Scope
This document specifies a method (Baumann) for the macrographic examination of steel by means of
contact printing using silver salts and acid.
The method is applicable to steels of which the sulphur content is less than 0,40 %. This method can
also be applied to cast irons.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
4 General
4.1 The sulphur print test is essentially a qualitative test. It is inadvisable to evaluate the sulphur
content of a given steel merely on the basis of its sulphur print.
4.2 Experience shows that the degree of darkening of the photo-sensitive emulsion is not always
in proportion to the quantity of sulphides present in the metal. Certain factors may influence the
macrographic attack to a greater or lesser extent; as examples, the following may be quoted:
— the chemical composition of the steel: the presence of certain elements modifies the type and shape
of the sulphides and consequently the appearance of the image obtained, for example concentrations
of titanium greater than 0,1 % give prints which do not reveal sulphides;
— the surface condition of the sample: the presence of surface cold working may alter the image
obtained;
— the sensitivity of the photographic paper.
4.3 The use of the test, and the conditions for interpreting the results observed, depend on the
particular case: details are laid down in product standards or shall be subject to special agreement.
5 Principle and aim of the test
5.1 The aim of macrographic examination by sulphur printing is to detect, by printing on photo-
sensitive papers previously soaked in acid, the position o
...
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