EN ISO 376:2011

SLOVENSKI STANDARD
01-februar-2012
1DGRPHãþD
SIST EN ISO 376:2005
Kovinski materiali - Umerjanje merilnikov sile, ki se uporabljajo za preverjanje
preskusnih strojev z enoosno obremenitvijo (ISO 376:2011)
Metallic material - Calibration of force-proving instruments used for the verification of
uniaxial testing machines (ISO 376:2011)
Metallische Werkstoffe - Kalibrierung der Kraftmessgeräte für die Prüfung von
Prüfmaschinen mit einachsiger Beanspruchung (ISO 376:2011)
Matériaux métalliques - Étalonnage des instruments de mesure de force utilisés pour la
vérification des machines d'essais uniaxiaux (ISO: 376:2011)
Ta slovenski standard je istoveten z: EN ISO 376:2011
ICS:
77.040.10 Mehansko preskušanje kovin Mechanical testing of metals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 376
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2011
ICS 77.040.10 Supersedes EN ISO 376:2004
English Version
Metallic materials - Calibration of force-proving instruments used
for the verification of uniaxial testing machines (ISO 376:2011)
Matériaux métalliques - Étalonnage des instruments de Metallische Werkstoffe - Kalibrierung der Kraftmessgeräte
mesure de force utilisés pour la vérification des machines für die Prüfung von Prüfmaschinen mit einachsiger
d'essais uniaxiaux (ISO 376:2011) Beanspruchung (ISO 376:2011)
This European Standard was approved by CEN on 4 June 2011.

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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 376:2011: E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
This document (EN ISO 376:2011) has been prepared by Technical Committee ISO/TC 164 "Mechanical
testing of metals" in collaboration with Technical Committee ECISS/TC 101 “Test methods for steel (other
than chemical analysis)” the secretariat of which is held by AFNOR.
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 December 2011, and conflicting national standards shall be withdrawn
at the latest by December 2011.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 376:2004.
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, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 376:2011 has been approved by CEN as a EN ISO 376:2011 without any modification.

INTERNATIONAL ISO
STANDARD 376
Fourth edition
2011-06-15
Metallic materials — Calibration of force-
proving instruments used for the
verification of uniaxial testing machines
Matériaux métalliques — Étalonnage des instruments de mesure de
force utilisés pour la vérification des machines d'essais uniaxiaux

Reference number
ISO 376:2011(E)
©
ISO 2011
ISO 376:2011(E)
©  ISO 2011
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 either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
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Published in Switzerland
ii © ISO 2011 – All rights reserved

ISO 376:2011(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Symbols and their designations .1
5 Principle.2
6 Characteristics of force-proving instruments .3
7 Calibration of the force-proving instrument.3
8 Classification of the force-proving instrument .8
9 Use of calibrated force-proving instruments.10
Annex A (informative) Example of dimensions of force transducers and corresponding loading
fittings.11
Annex B (informative) Additional information .18
Annex C (informative) Measurement uncertainty of the calibration and subsequent use of the
force-proving instrument.21
Bibliography.30

ISO 376:2011(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 376 was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals, Subcommittee
SC 1, Uniaxial testing.
This fourth edition cancels and replaces the third edition (ISO 376:2004), which has been technically revised
(for details, see the introduction).
iv © ISO 2011 – All rights reserved

ISO 376:2011(E)
Introduction
An ISO/TC 164/SC 1 working group has developed procedures for determining the measurement uncertainty
of force-proving instruments, and these procedures have been added to this fourth edition as a new annex
(Annex C).
In addition, this fourth edition allows the calibration to be performed in two ways:
⎯ with reversible measurement for force-proving instruments which are going to be used with increasing
and decreasing forces;
⎯ without reversible measurement for force-proving instruments which are going to be used only with
increasing forces.
In the first case, i.e. when the force-proving instrument is going to be used for reversible measurements, the
calibration has to be performed with increasing and decreasing forces to determine the hysteresis of the force-
proving instrument. In this case, there is no need to perform a creep test.
In the second case, i.e. when the force-proving instrument is not going to be used for reversible
measurements, the calibration is performed with increasing forces only but, in addition, a creep test has to be
performed. In this case, there is no need to determine the hysteresis.

INTERNATIONAL STANDARD ISO 376:2011(E)

Metallic materials — Calibration of force-proving instruments
used for the verification of uniaxial testing machines
1 Scope
This International Standard specifies a method for the calibration of force-proving instruments used for the
static verification of uniaxial testing machines (e.g. tension/compression testing machines) and describes a
procedure for the classification of these instruments.
This International Standard is applicable to force-proving instruments in which the force is determined by
measuring the elastic deformation of a loaded member or a quantity which is proportional to it.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
force-proving instrument
whole assembly from the force transducer through to, and including, the indicator
4 Symbols and their designations
Symbols and their designations are given in Table 1.
ISO 376:2011(E)
Table 1 — Symbols and their designations
Symbol Unit Designation
b % Relative reproducibility error with rotation
b′ % Relative repeatability error without rotation
c % Relative creep error
F N Maximum capacity of the transducer
f
F N Maximum calibration force
N
f % Relative interpolation error
c
f % Relative zero error
a
i — Reading on the indicator after removal of force
f
a
i — Reading on the indicator before application of force
o
a
i — Reading on the indicator 30 s after application or removal of the maximum calibration force
a
i — Reading on the indicator 300 s after application or removal of the maximum calibration force
r N Resolution of the indicator
v % Relative reversibility error of the force-proving instrument
X — Deflection with increasing test force
X — Computed value of deflection
a
X ′ — Deflection with decreasing test force
X — Maximum deflection from runs 1, 3 and 5
max
X — Minimum deflection from runs 1, 3 and 5
min
X — Deflection corresponding to the maximum calibration force
N
X — Average value of the deflections with rotation
r
X — Average value of the deflections without rotation
wr
a
Reading value corresponding to the deflection.
5 Principle
Calibration consists of applying precisely known forces to the force transducer and recording the data from the
indicator, which is considered an integral part of the force-proving instrument.
When an electrical measurement is made, the indicator may be replaced by another indicator and the force-
proving instrument need not be recalibrated provided the following conditions are fulfilled.
a) The original and replacement indicators have calibration certificates, traceable to national standards,
which give the results of calibration in te
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