ISO/TR 12735-2:1996

TECHNICAL lSO/TR
REPORT 12735-2
First edition
1996-l 2-l 5
Mechanical testing of metals - Symbols
used with their definitions -
Part 2:
Recommendations for the development of
symbols and definitions
Essais mkaniques des m&aux - Symboles utilish et leurs dgfinitions -
Partie 2: Recommandations pour le d&eloppement des symboles et des
d& finitions
Reference number
ISO/TR 12735-2:1996(E)

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ISO/TR 12735-2: 1996(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work of
preparing International Standards is normally carried out through IS0
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. IS0
collaborates closely with the International Electrotechnical Commission
(I EC) on all matters of electrotechnical standardization.
The main task of technical committees is to prepare International
Standards, but in exceptional circumstances a technical committee may
propose the publication of a Technical Report of one of the following
types:
- type 1 , whe n the required suppor t cannot be obtained for the publi-
cation of an In ternational Standard, despite repeated effo rts;
- type 2, when the subject is still under technical development or where
for any other reason there is the future but not immediate possibility
of an agreement on an International Standard;
- type 3, when a technical committee has collected data of a different
kind from that which is normally published as an International
Standard (“state of the art”, for example).
Technical Reports of types 1 and 2 are subject to review within three
years of publication, to decide whether they can be transformed into
International Standards. Technical Reports of type 3 do not necessarily
have to be reviewed until the data they provide are considered to be no
longer valid or useful.
ISOnR 12735-2, which is a Technical Report of type 2, was prepared by
Technical Committee lSO/TC 164, Mechanical testing of metals.
lSO/TR 12735 consists of the following parts, under the general title
Mechanical testing of metals - Symbols used with their definitions:
Part 7: Symbols and definitions in published standards
- Part 2: Recommendations for the development of symbols
definitions
0 IS0 1996
All rights reserved. Unless otherwise specified, no part of this publication may be
reproduced or utilized in any form or by any means, electronic or mechanical, including
photocopying and microfilm, without permission In writing from the publisher.
lnternatronal Organization for Standardization
Case Postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
II

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lSO/TR 12735-2: 1996(E)
@ IS0
Introduction
This part of lSO/TR 12735 has been prepared to provide the appropriate
means of avoiding contradiction and misunderstanding and to standardize
various kinds of symbols and their definitions generally used in lSO/TC 164
documents. Wherever possible the same symbol has been used to denote
the same type of parameter in different tests but differing types of test
piece, product form and test have to be taken into account. This has not
been universally possible and symbols should always be considered in the
context of the specific method of test being used.
Symbols are attached to concepts and phenomena in order to
communicate data succinctly. They must be simple to use and readily
comprehensible in both speech and writing across geographical frontiers
and language barriers.

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ISO/TR 12735-2: 1996(E)
TECHNICAL REPORT @ IS0
Mechanical testing of metals - Symbols used with their
definitions -
Part 2:
Recommendations for the development of symbols and definitions
1 Scope
This part of lSO/TR 12735 contains recommendations on the choice of definitions and symbols to be used in IS0
International Standards for methods of mechanical testing of metallic materials which are the specific responsibility
of Technical Committee lSO/TC 164.
It establishes the procedure for co-ordinating the adoption of suitable symbols between WG 1 and the technical
subcommittees of lSO/TC 164. Furthermore, it establishes a procedure for the review of both parts of the
/
document itself at regular intervals by lSO/TC 164 WG 1.
2 The use of definitions
(See lSO/lEC Directives, Part 3, annex B.1.4.)
2.1 A definition is a statement of the precise meaning of a word or term.
2.2 The use of a definition in a standard prepared by a TC 164 subcommittee is recommended under the
following conditions.
2.2.1 Where one of many widely used meanings of a word or a term is to be applied.
2.2.2 When the word or term is not widely recognized, because it is specific only to the test or type of test to
which the standard refers.
2.2.3 If the subcommittee believes that ambiguity may arise if a definition of the word or term is not included in
the standard.
2.3 Definitions are gathered in a clause which follows immediately after “Normative references”.
2.4 It is recommended that the definitions be listed in alphabetical order. The purpose is to ease the task of
locating the definition for readers of the standard, who will generally be referring back from subsequent clauses to
refresh their minds on the precise meaning of a word or a term.
In many standards however, symbols and definitions are presented in their order of importance or order of use
NOTE -
within the body of the standard.

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0 IS0
ISO/TR 12735-2: 1996(E)
2.5 It is recommended that each definition be given a sub-clause number to assist communication between
readers.
3 The use of symbols
3.1 A symbol is a combination of marks or characters representing a concept, an object, a measurement or a
process.
3.2 The purpose in using a symbol is to reduce the time and space required to transmit the concept or the data
attached to the concept from person to person, visually or verbally, while simultaneously reducing the effort
required on the part of the receiver to comprehend the information.
33 . It is recommended that symbols be employed whenever this purpose can be achieved.
34 . Symbols are built up from components in a formal structure as described in clause 5.
3.5 Mathematical symbols already widely used to represent algebraic or analytic functions such as integration or
summation shall not be used within lSO/TC 164 to represent other concepts.
3.6 Symbols are to be first presented in tabular form, the appropriate clause and table to follow immediately after
the Definitions (see 2.3).
3.7 It is recommended that the symbol table comprise one or two header rows for numbering and titlrng the
table, followed by three vertical columns for:
a) the symbols themselves;
b) the units in which the data relevant to the symbol are presented;
the designation or concept which the symbol is to represent in the rest of the document.
cl
The word Designation is preferred to the word Defi’nition as the heading for the 3rd column of the symbols table.
NOTE -
Part 1 of lSO/TR 12735 contains many examples.
38 . It is recommended that the tables be presented in alphabetical order of the symbols used (see 2.4).
when printed, symbols representing variables be set in italic script to distinguish
39 It is recomm e nded that,
them from surroun d ing text.
4 Explanatory figures
behind a symbol or definition, or the application of that
4.1 Comprehens ion and communicat ion of the concept
concept, will often be enhanced by the inclusion of a figure
4.2 It is recommended that figures be used wherever beneficial.
4.3 Figures shall always be drafted in accordance with current IS0 rules. (See lSO/IEC Directives, Part 3, 4.3.)
4.4 If a figure is used to illustrate one or more concepts and includes the symbols used to designate those
concepts, then the figure should be referenced in the designation column of the symbol table [see 3.7 a)] as part of
the designation for each of those symbols.
2

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ISO/TR 12735-2: 1996(E)
0 IS0
5 The components of a symbol
5.1 When preparing a standard, it is often necessary to distinguish between:
several different states of a single parameter, or
a)
b) several different but closely related items from a single class of parameter.
5.2 In order to achiev
...