SIST EN ISO 376:2004
(Main)Metallic materials - Calibration of force-proving instruments used for the verification of uniaxial testing machines (ISO 376:1999)
Metallic materials - Calibration of force-proving instruments used for the verification of uniaxial testing machines (ISO 376:1999)
This standard covers 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 classifying these instruments.
Metallische Werkstoffe - Kalibrierung der Kraftmessgeräte für die Prüfung von Prüfmaschinen mit einachsiger Beanspruchung (ISO 376:1999)
In dieser Internationalen Norm ist die Kalibrierung von Kraftmessgeräten für die statische Prüfung einachsiger Prüfmaschinen (z. B. Zug-Druckprüfmaschinen) festgelegt. Es wird ein Verfahren für die Klassifizierung dieser Geräte beschrieben. Das Kraftmessgerät wird als das gesamte Gerät vom Kraftaufnehmer bis und einschließlich der Anzeigeeinrichtung definiert. Diese Internationale Norm gilt allgemein für Kraftmessgeräte, bei denen die Kraft durch Messung der elastischen Formveränderung eines Verformungskörpers oder einer ihr proportionalen Messgröße bestimmt wird.
Matériaux métalliques - Etalonnage des instruments de mesure de force utilisés pour la vérification des machines d'essais uniaxiaux (ISO 376:1999)
Kovinski materiali - Kalibracija merilnikov sile za preverjanje enoosnih preskuševalnih strojev (ISO 376:1999)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 376:2004
01-marec-2004
1DGRPHãþD
SIST EN 10002-3:1996
Kovinski materiali - Kalibracija merilnikov sile za preverjanje enoosnih
preskuševalnih strojev (ISO 376:1999)
Metallic materials - Calibration of force-proving instruments used for the verification of
uniaxial testing machines (ISO 376:1999)
Metallische Werkstoffe - Kalibrierung der Kraftmessgeräte für die Prüfung von
Prüfmaschinen mit einachsiger Beanspruchung (ISO 376:1999)
Matériaux métalliques - Etalonnage des instruments de mesure de force utilisés pour la
vérification des machines d'essais uniaxiaux (ISO 376:1999)
Ta slovenski standard je istoveten z: EN ISO 376:2002
ICS:
77.040.10 Mehansko preskušanje kovin Mechanical testing of metals
SIST EN ISO 376:2004 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 376:2004
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SIST EN ISO 376:2004
EUROPEAN STANDARD
EN ISO 376
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2002
ICS 77.040.10 Supersedes EN 10002-3:1994
English version
Metallic materials - Calibration of force-proving instruments used
for the verification of uniaxial testing machines (ISO 376:1999)
Matériaux métalliques - Etalonnage 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 376:1999)
Beanspruchung (ISO 376:1999)
This European Standard was approved by CEN on 26 December 2001.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2002 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 376:2002 E
worldwide for CEN national Members.
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SIST EN ISO 376:2004
EN ISO 376:2002 (E)
CORRECTED 2002-10-02
Foreword
The text of ISO 376:1999 has been prepared by Technical Committee ISO/TC 164 "Mechanical testing
of metals" of the International Organization for Standardization (ISO) and has been taken over as EN
ISO 376:2002 by Technical Committee ECISS/TC 1 "Steel - Mechanical testing", 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 July 2002, and conflicting national standards shall be
withdrawn at the latest by July 2002.
This document supersedes EN 10002-3:1994.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands,
Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 376:1999 has been approved by CEN as EN ISO 376:2002 without any modifications.
NOTE Normative references to International Standards are listed in Annex ZA (normative).
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SIST EN ISO 376:2004
EN ISO 376:2002 (E)
Annex ZA
(normative)
Normative references to international publications
with their relevant European publications
This European Standard incorporates by dated or undated reference, provisions from other publications.
These normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications
apply to this European Standard only when incorporated in it by amendment or revision. For undated
references the latest edition of the publication referred to applies (including amendments).
NOTE Where an International Publication has been modified by common modifications, indicated by
(mod.), the relevant EN/HD applies.
Publication Year Title EN Year
ISO 7500-1 1999 Metallic materials - Verification of EN ISO 7500-1 1999
static uniaxial testing machines - Part
1: Tension/compression testing
machines
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SIST EN ISO 376:2004
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SIST EN ISO 376:2004
INTERNATIONAL ISO
STANDARD 376
Second edition
1999-08-15
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
A
Reference number
ISO 376:1999(E)
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SIST EN ISO 376:2004
ISO 376:1999(E)
Contents Page
1 Scope .1
2 Normative reference .1
3 Principle.1
4 Characteristics of force-proving instruments.2
5 Symbols, units and designations.3
6 Calibration of the force-proving instrument .3
7 Classification of the force-proving instrument.7
8 Use of calibrated force-proving instruments.9
Annex A (informative) Example of dimensions of force transducers and corresponding loading fittings .10
Annex B (informative) Additional information.17
Bibliography.20
© ISO 1999
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.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
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SIST EN ISO 376:2004
© ISO
ISO 376:1999(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 3.
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.
International Standard ISO 376 was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals,
Subcommittee SC 1, Uniaxial testing.
This second edition cancels and replaces the first edition (ISO 376:1987) which has been technically revised.
Annexes A and B of this International Standard are for information only.
iii
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SIST EN ISO 376:2004
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SIST EN ISO 376:2004
INTERNATIONAL STANDARD © ISO ISO 376:1999(E)
Metallic materials — Calibration of force-proving instruments used
for the verification of uniaxial testing machines
1 Scope
This International Standard covers 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 classifying
these instruments. A force-proving instrument is defined as being the whole assembly from the force transducer
through to and including the indicator. This International Standard generally applies 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 reference
The following normative document contains 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 edition of the normative document 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 7500-1, Metallic materials — Verification of static uniaxial testing machines — Part 1: Tension/compression
testing machines — Verification and calibration of the force-measuring system.
3 Principle
Calibration consists of applying precisely-known forces to the loaded member and recording the data from the
deflection measuring system, 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 terms of electrical base units (volt, ampere). The replacement indicator shall be
calibrated over a range equal to or greater than the range for which it is used with the force-proving instrument
and the resolution of the indicator shall be at least equal to the resolution of the indicator when it is used with
the force-proving instrument.
b) The units and excitation source of the replacement indicator should be respectively of the same quantity (e.g.
5 V, 10 V) and type (e.g. AC or DC carrier frequency).
c) The uncertainty of each indicator (both the original and the replacement indicators) shall not influence the
uncertainty of the whole assembly of the force-proving instrument. It is recommended that the uncertainty of the
replacement indicator should be no greater than 1/3 of the uncertainty of the entire system.
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SIST EN ISO 376:2004
© ISO
ISO 376:1999(E)
4 Characteristics of force-proving instruments
4.1 Identification of the force-proving instrument
All the elements of the force-proving instrument (including the cables for electrical connection) shall be individually
and uniquely identified, e.g. by the name of the manufacturer, the model and the serial number. For the force
transducer, the maximum working force shall be indicated.
4.2 Application of force
The force transducer and its loading fittings shall be designed so as to ensure axial application of force, whether in
tension or compression.
Examples of loading fittings are given in annex A.
4.3 Measurement of deflection
Measurement of the deflection of the loaded member of the force transducer may be carried out by mechanical,
electrical, optical or other means with adequate accuracy and stability.
The type and the quality of the deflection measuring system determine whether the force-proving instrument is
classified only for specific calibration forces or for interpolation (see clause 7).
Generally, the use of force-proving instruments with dial gauges as a means of measuring the deflection is limited to
the forces for which the instruments have been calibrated. The dial gauge, if used over a long travel, may contain
large localised periodic errors which produce an uncertainty too great to permit interpolation between calibration
forces. The dial gauge may be used for interpolation if its periodic error has a negligible influence on the
interpolation error of the force-proving instrument.
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SIST EN ISO 376:2004
© ISO
ISO 376:1999(E)
5 Symbols, units and designations
For the purpose of this International Standard, the symbols, units and designations given in Table 1 shall apply.
Table 1 — Symbols, units and designations
Symbol Unit Designation
F N Maximum capacity of the measuring range
N
F N Maximum capacity of the transducer
f
a
i – Reading on the indicator before application of force
o
a
i – Reading on the indicator after removal of force
f
X – Deflection with increasing test force
X' – Deflection with decreasing test force
X – Average value of the deflections with rotation
r
X – Average value of deflections without rotation
wr
X – Maximum deflection
max
X – Minimum deflection
min
X – Computed value of deflection
a
X – Deflection corresponding to the maximum capacity
N
b % Relative reproducibility error with rotation
b' % Relative repeatability without rotation
f % Relative zero error
o
f % Relative interpolation error
c
r – Resolution of the indicator
v % Relative reversibility error of the force-proving instrument
a
Reading value corresponding to the deflection.
6 Calibration of the force-proving instrument
6.1 General
Before undertaking the calibration of the force-proving instrument, ensure that this instrument is able to be
calibrated. This can be done by means of preliminary tests such as those defined below and given as examples.
6.1.1 Overloading test
This optional test is described in clause B.1.
6.1.2 Verification relating to application of forces
Ensure
that the attachment system of the force-proving instrument allows axial application of the force when the
instrument is used for tensile testing;
that there is no interaction between the force transducer and its support on the calibration machine when the
instrument is used for compression testing.
Clause B.2 gives an example of a method which can be used.
NOTE Other methods can be used, e.g. a method using a flat-based transducer with a spherical button or upper bearing
surface.
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SIST EN ISO 376:2004
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ISO 376:1999(E)
6.1.3 Variable voltage test
This test is left to the discretion of the calibration service. For force-proving instruments requiring an electrical
supply, verify that a variation of ± 10 % of the line voltage has no significant effect. This verification can be carried
out by means of a force transducer simulator or by another appropriate method.
6.2 Resolution of the indicator
6.2.1 Analogue scale
The thickness of the graduation marks on the scale shall be uniform and the width of the pointer shall be
approximately equal to the width of a graduation mark.
The resolution (r) of the indicator shall be obtained from the ratio between the width of the pointer and the centre-to-
centre distance between two adjacent scale graduation marks (scale interval), the recommended ratios being 1/2,
1/5 or 1/10, a spacing of 1,25 mm or greater being required for the estimation of a tenth of the division on the scale.
A vernier scale of dimensions appropriate to the analogue scale may be used to allow direct fractional reading of the
instrument scale division.
6.2.2 Digital scale
The resolution is considered to be one increment of the last active number on the numerical indicator, provided that
the indication does not fluctuate by more than one increment with no force applied to the instrument.
6.2.3 Variation of readings
If the readings fluctuate by more than the value previously calculated for the resolution (with no force applied to the
instrument), the resolution shall be deemed to be equal to half the range of fluctuation.
6.2.4 Units
The resolution (r) shall be converted to units of force.
6.3 Minimum force
Taking into consideration the accuracy with which the deflection of the instrument may be read during calibration or
during its subsequent use for verifying machines, the minimum force applied to a force-proving instrument shall
comply with the two following conditions:
a) the minimum force shall be greater than or equal to:
4 000 3 r for class 00
2 000 3 r for class 0,5
1 000 3 r for class 1
500 3 r for class 2
b) the minimum force shall be greater than or equal to 0,02 F .
f
6.4 Calibration procedure
6.4.1 Preloading
Before the calibration forces are applied, in a given mode (tension or compression), the maximum force shall be
applied to the instrument three times. The duration of the application of each preload shall be between 1 min and
1,5 min.
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SIST EN ISO 376:2004
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ISO 376:1999(E)
6.4.2 Procedure
The calibration shall be carried out by applying two series of calibration forces to the force-proving instrument with
increasing values only, without disturbing the device.
Then apply at least two further series of increasing and decreasing values. Between each of the further series of
forces, the force-proving instrument shall be rotated symmetrically on its axis to positions uniformly distributed over
360° (i.e. 0°, 120°, 240°). If this is not possible, it is permissible to adopt the following positions: 0°, 180° and 360°
(see Figure 1).
For the determination of the interpolation curve, the number of forces shall be not less than eight, and these forces
shall be distributed as uniformly as possible over the calibration range.
NOTE 1 If a periodic error is suspected, it is recommended that intervals between the forces which correspond to the
periodicity of this error should be avoided.
NOTE 2 This procedure determines only the maximum hysteresis of the device. Accurate determination of the hysteresis can
only be performed on dead-weight machines.
The force-proving instrument shall be pre-loaded three times to the maximum force in the direction in which the
subsequent forces are to be applied. When the direction of loading is changed, the maximum force shall be applied
three times in the new direction.
The readings corresponding to no force shall be noted after waiting at least 30 s after the force has been totally
removed.
NOTE 3 There should be a wait of at least 3 min between subsequent measurement series.
Instruments with detachable parts shall be dismantled, as for packaging and transport, at least once during
calibration. In general, this dismantling shall be carried out between the second and third series of calibration forces.
The maximum force shall be applied to the force-proving instrument at least three times before the next series of
forces is applied.
Before starting the calibration of an electrical force-proving instrument, the zero signal may be noted (see
clause B.3).
6.4.3 Loading conditions
The time interval between two successive loadings shall be as uniform as possible, and no reading shall be taken at
least 30 s after the start of the force change. The calibration shall be performed at a temperature stable to 6 1 °C,
this temperature shall be within the range 18 °C to 28 °C and shall be recorded. Sufficient time shall be allowed for
the force-proving instrument to attain a stable temperature.
NOTE When it is known that the force-proving instrument is not temperature compensated, care should be taken to ensure
that temperature variations do not affect the calibration.
Strain gauge transducers shall be energized for at least 30 min before calibration.
6.4.4 Determination of deflection
A deflection is defined as the difference between a reading under force and a reading without force.
NOTE This definition of deflection applies to output readings in electrical units as well as to output readings in length units.
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SIST EN ISO 376:2004
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ISO 376:1999(E)
Figure 1 — Positions of the force-proving instrument
6.5 Assessment of the force-proving instrument
6.5.1 Relative reproducibility and repeatability errors, b and b'
These errors are calculated for each calibration force and in the two cases: with rotation of the proving instrument
(b) and without rotation (b' ), using the following equations:
XX-
max min
b =·100
X
r
where
XX++X
13 5
X
=
r
3
-XX
21
100
b¢=·
X
wr
where
XX+
12
X =
wr
2
6.5.2 Relative interpolation error, f
c
This error is determined using a first-, second-, or third-degree equation giving the deflection as a
...
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