SIST EN ISO 4545-1:2018
(Main)Metallic materials - Knoop hardness test - Part 1: Test method (ISO 4545-1:2017)
Metallic materials - Knoop hardness test - Part 1: Test method (ISO 4545-1:2017)
This document specifies the Knoop hardness test method for metallic materials for test forces from
0,009 807 N to 19,613 N.
The Knoop hardness test is specified in this document for lengths of indentation diagonals ≥0,020 mm.
Using this method to determine Knoop hardness from smaller indentations is outside the scope of this
document as results would suffer from large uncertainties due to the limitations of optical measurement
and imperfections in tip geometry. ISO 14577-1 allows the determination of hardness from smaller
indentations.
A periodic verification method is specified for routine checking of the testing machine in service by
the user.
Special considerations for Knoop testing of metallic coatings can be found in ISO 4516.
Metallische Werkstoffe - Härteprüfung nach Knoop - Teil 1: Prüfverfahren (ISO 4545-1:2017)
Dieses Dokument legt das Verfahren für die Härteprüfung nach Knoop an metallischen Werkstoffen für Prüfkräfte von 0,009 807 N bis 19,613 N fest.
In diesem Dokument ist die Härteprüfung nach Knoop festgelegt für Eindruckdiagonallängen ≥ 0,020 mm. Die Verwendung dieses Verfahrens zur Bestimmung der Knoop-Härte für kleinere Eindrücke gehört nicht zum Anwendungsbereich in diesem Dokument, weil die Resultate wegen Grenzen der optischen Messung und Unvollkommenheiten der Kegelgeometrie mit großer Unsicherheit behaftet wären. ISO 14577 1 erlaubt die Härte-Bestimmung von kleineren Eindrücken.
Eine periodische Überprüfung ist angegeben zur laufenden Kontrolle der Prüfmaschine in Betrieb durch den Anwender.
Besondere Überlegungen zur Prüfung metallischer Überzüge nach Knoop können ISO 4516 entnommen werden.
Matériaux métalliques - Essai de dureté Knoop - Partie 1 : Méthode d'essai (ISO 4545-1:2017)
ISO 4545-1:2017 spécifie la méthode d'essai de dureté Knoop pour les matériaux métalliques, pour des forces d'essai comprises entre 0,009 807 N et 19,613 N.
Le présent document spécifie l'essai de dureté Knoop pour les longueurs de diagonale d'empreinte ≥ 0,020 mm. L'utilisation de cette méthode pour déterminer la dureté Knoop d'empreintes plus petites ne fait pas partie du domaine d'application du présent document, car les résultats ainsi obtenus présenteraient des incertitudes élevées en raison des limitations du mesurage optique et des imperfections concernant la géométrie de la pointe. L'ISO 14577‑1 permet de déterminer la dureté des empreintes plus petites.
Une méthode de vérification périodique est spécifiée pour la vérification de routine, par l'utilisateur, de la machine d'essai utilisée.
Des considérations particulières pour les essais Knoop des revêtements métalliques sont disponibles dans l'ISO 4516.
Kovinski materiali - Preskus trdote po Knoopu - 1. del: Preskusna metoda (ISO 4545-1:2017)
Ta dokument določa metodo za preskus trdote po Knoopu za kovinske materiale s preskusnimi silami od 0,009 807 N do 19,613 N.
Preskus trdote po Knoopu je v tem dokumentu določen za dolžine diagonal zarez ≥ 0,020 mm. Uporaba te metode za določanje trdote po Knoopu na podlagi manjših zarez ne sodi v področje uporabe tega dokumenta, saj bi bili rezultati nezanesljivi zaradi negotovosti, povezane z omejitvami optičnega merjenja in nepravilnostmi geometrije konice. Določevanje trdote na podlagi manjših zarez omogoča standard ISO 14577-1.
Določena je tudi metoda za redno preverjanje pri rutinskem pregledovanju naprave za preskušanje, ki jo uporablja
uporabnik. Posebne zahteve za preskušanje kovinskih prevlek so navedene v standardu ISO 4516.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 4545-1:2018
01-julij-2018
1DGRPHãþD
SIST EN ISO 4545-1:2006
Kovinski materiali - Preskus trdote po Knoopu - 1. del: Preskusna metoda (ISO
4545-1:2017)
Metallic materials - Knoop hardness test - Part 1: Test method (ISO 4545-1:2017)
Metallische Werkstoffe - Härteprüfung nach Knoop - Teil 1: Prüfverfahren (ISO 4545-
1:2017)
Matériaux métalliques - Essai de dureté Knoop - Partie 1 : Méthode d'essai (ISO 4545-
1:2017)
Ta slovenski standard je istoveten z: EN ISO 4545-1:2018
ICS:
77.040.10 Mehansko preskušanje kovin Mechanical testing of metals
SIST EN ISO 4545-1:2018 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 4545-1:2018
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SIST EN ISO 4545-1:2018
EN ISO 4545-1
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2018
EUROPÄISCHE NORM
ICS 77.040.10 Supersedes EN ISO 4545-1:2005
English Version
Metallic materials - Knoop hardness test - Part 1: Test
method (ISO 4545-1:2017)
Matériaux métalliques - Essai de dureté Knoop - Partie Metallische Werkstoffe - Härteprüfung nach Knoop -
1: Méthode d'essai (ISO 4545-1:2017) Teil 1: Prüfverfahren (ISO 4545-1:2017)
This European Standard was approved by CEN on 30 November 2017.
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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 4545-1:2018 E
worldwide for CEN national Members.
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SIST EN ISO 4545-1:2018
EN ISO 4545-1:2018 (E)
Contents Page
European foreword . 3
2
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SIST EN ISO 4545-1:2018
EN ISO 4545-1:2018 (E)
European foreword
This document (EN ISO 4545-1:2018) 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 September 2018, and conflicting national standards
shall be withdrawn at the latest by September 2018.
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 ISO 4545-1:2005.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 4545-1:2017 has been approved by CEN as EN ISO 4545-1:2018 without any
modification.
3
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SIST EN ISO 4545-1:2018
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SIST EN ISO 4545-1:2018
INTERNATIONAL ISO
STANDARD 4545-1
Second edition
2017-12
Metallic materials — Knoop
hardness test —
Part 1:
Test method
Matériaux métalliques — Essai de dureté Knoop —
Partie 1: Méthode d'essai
Reference number
ISO 4545-1:2017(E)
©
ISO 2017
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SIST EN ISO 4545-1:2018
ISO 4545-1:2017(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved
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SIST EN ISO 4545-1:2018
ISO 4545-1:2017(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Symbols and designations . 2
5.1 Symbols and designations used in this document . 2
5.2 Designation of hardness number . 3
6 Testing machine . 3
6.1 Testing machine . 3
6.2 Indenter . . 3
6.3 Diagonal measuring system . 4
7 Test piece . 4
7.1 Test Surface . 4
7.2 Preparation . 4
7.3 Thickness . 4
7.4 Support of unstable test pieces . 4
8 Procedure. 5
8.1 Test temperature . 5
8.2 Test force . 5
8.3 Periodic verification . 5
8.4 Test piece support . 5
8.5 Focus on test surface . 5
8.6 Test force application . 6
8.7 Prevention of the effect of shock or vibration . 6
8.8 Minimum distance between adjacent indentations . 6
8.9 Measurement of diagonal length . 7
8.10 Calculation of hardness value . 7
9 Uncertainty of the results . 7
10 Test report . 7
Annex A (normative) Procedure for periodic checking of the testing machine, diagonal
measuring system and the indenter by the user . 9
Annex B (informative) Uncertainty of the measured hardness values .11
Annex C (informative) Knoop hardness measurement traceability .18
Annex D (informative) CCM — Working group on hardness .22
Annex E (informative) Adjustment of Köhler illumination systems .23
Bibliography .24
© ISO 2017 – All rights reserved iii
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SIST EN ISO 4545-1:2018
ISO 4545-1:2017(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 on 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 the following
URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals,
Subcommittee SC 3, Hardness testing.
This second edition cancels and replaces the first edition (ISO 4545-1:2005), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— all references have been removed of indentation diagonals <0,020 mm;
— the resolution requirements have been defined for the measuring system;
— the lower test force limit of the Knoop hardness test has been expanded to 0,009 807 N;
— the requirements for the periodic (weekly or daily) verifications of the testing machine have been
defined as normative, the maximum permissible bias value has been revised, and the requirements
for the maximum permissible error in measuring a reference indentation have been revised;
— the recommendations for inspection and monitoring of the indenter have been added (moved from
ISO 4545-2);
— the requirements have been revised for the approach velocity of the indenter prior to contact with
the sample surface;
— the timing requirements for the test force application and the duration at maximum test force are
revised to indicate target time values;
— Figure 3 has been added illustrating the requirements for the minimum distance between
indentations; the distances have been stated with respect to the indentation centres rather than
the indentation limits, but the requirements have not changed;
— the requirements have been added to the test report for reporting the test date and any hardness
conversion method used;
iv © ISO 2017 – All rights reserved
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SIST EN ISO 4545-1:2018
ISO 4545-1:2017(E)
— Annexes C, D and E have been added concerning Knoop hardness measurement traceability, the
CCM — Working group on hardness and adjustment of Köhler illumination systems, respectively.
A list of all parts in the ISO 4545 series can be found on the ISO website.
© ISO 2017 – All rights reserved v
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SIST EN ISO 4545-1:2018
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SIST EN ISO 4545-1:2018
INTERNATIONAL STANDARD ISO 4545-1:2017(E)
Metallic materials — Knoop hardness test —
Part 1:
Test method
1 Scope
This document specifies the Knoop hardness test method for metallic materials for test forces from
0,009 807 N to 19,613 N.
The Knoop hardness test is specified in this document for lengths of indentation diagonals ≥0,020 mm.
Using this method to determine Knoop hardness from smaller indentations is outside the scope of this
document as results would suffer from large uncertainties due to the limitations of optical measurement
and imperfections in tip geometry. ISO 14577-1 allows the determination of hardness from smaller
indentations.
A periodic verification method is specified for routine checking of the testing machine in service by
the user.
Special considerations for Knoop testing of metallic coatings can be found in ISO 4516.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 4545-2, Metallic materials — Knoop hardness test — Part 2: Verification and calibration of testing
machines
ISO 4545-3, Metallic materials — Knoop hardness test — Part 3: Calibration of reference blocks
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:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
4 Principle
A diamond indenter, in the form of a rhombic-based pyramid with angles, α and β, between opposite
edges respectively equal to 172,5° and 130° at the vertex, is forced into the surface of a test piece
followed by measurement of the long diagonal, d, of the indentation remaining in the surface after
removal of the test force, F (see Figures 1 and 2).
© ISO 2017 – All rights reserved 1
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SIST EN ISO 4545-1:2018
ISO 4545-1:2017(E)
Figure 1 — Principle of the test and indenter geometry
Figure 2 — Knoop indentation
The Knoop hardness is proportional to the quotient obtained by dividing the test force by the projected
area of the indentation, which is assumed to be a rhombic-based pyramid, and having at the vertex the
same angles as the indenter.
NOTE As applicable, this test document has adopted hardness test parameters as defined by the working
group on hardness (CCM-WGH) under the framework of the International Committee of Weights and Measures
(CIPM) Consultative Committee for Mass and Related Quantities (CCM) (see Annex D).
5 Symbols and designations
5.1 Symbols and designations used in this document
See Table 1 and Figures 1 and 2.
Table 1 — Symbols and designations
Symbol Designation
F Test force, in newtons (N)
d Length of the long diagonal, in millimetres
d Length of the short diagonal, in millimetres
s
α Angle between the opposite edges of the long diagonal at the vertex of the diamond pyramid
indenter (nominally 172,5°) (see Figure 1)
β Angle between the opposite edges of the short diagonal at the vertex of the diamond pyramid
(nominally 130°) (see Figure 1)
2
NOTE Standard acceleration due to gravity, g = 9,806 65 m/s , which is the conversion factor from kgf to N.
n
To reduce uncertainty, the Knoop hardness can be calculated using the actual indenter angles α and β.
2 © ISO 2017 – All rights reserved
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SIST EN ISO 4545-1:2018
ISO 4545-1:2017(E)
Table 1 (continued)
Symbol Designation
V Magnification of the measuring system
c Indenter constant, relating projected area of the indentation to the square of the length of the
long diagonal
β
tan
2
Indenter constant, c= , for nominal angles α and β, c is approximately 0,070 28
α
2tan
2
HK
Test force (kgf)
Knoop hardness =
2
Projected area of indentation (mm )
1 Test force (N)
=×
2
g
n Projected area of indentation (mm )
1 F
=×
2
g
n cd
For the nominal indenter constant c ≈ 0,070 28,
F
Knoop hardness ≈×1,451
2
d
2
NOTE Standard acceleration due to gravity, g = 9,806 65 m/s , which is the conversion factor from kgf to N.
n
To reduce uncertainty, the Knoop hardness can be calculated using the actual indenter angles α and β.
5.2 Designation of hardness number
Knoop hardness, HK, is designated as shown in the following example.
640 HK 0,1 ⁄20
Duration of test force (20 s)
if not within the speci ied range (10 s to 15 s)
Approximate kgf equivalent value of
applied test force where (0,1 kgf = 0,980 7 N)
Hardness symb ol
Knoop hardness valu e
6 Testing machine
6.1 Testing machine
The testing machine shall be capable of applying a predetermined force or forces within the desired
range of test forces, in accordance with ISO 4545-2.
6.2 Indenter
The indenter shall be a diamond in the shape of a rhombic-based pyramid, as specified in ISO 4545-2.
© ISO 2017 – All rights reserved 3
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SIST EN ISO 4545-1:2018
ISO 4545-1:2017(E)
6.3 Diagonal measuring system
The diagonal measuring system shall satisfy the requirements in ISO 4545-2.
Magnifications should be provided so that the diagonal can be enlarged to greater than 25 % but less
than 75 % of the maximum possible optical field of view. Many objective lenses are non-linear towards
the edge of the field of view.
NOTE A diagonal measuring system using a camera for measurement can use 100 % of the camera’s field of
view, provided it is designed to consider field of view limitations of the optical system.
The resolution required of the diagonal measuring system depends on the size of the smallest
indentation to be measured, and shall be in accordance with Table 2. In determining the resolution of
the measuring system, the resolution of the microscope optics, the digital resolution of the measuring
scale and the step-size of any stage movement, where applicable, should be taken into account.
Table 2 — Resolution of the measuring system
Diagonal length
Resolution of the measuring
d
system
mm
0,020 ≤ d < 0,080 0,000 4 mm
0,080 ≤ d 0,5 % of d
7 Test piece
7.1 Test Surface
The test shall be carried out on a polished surface, which is smooth and even, free from oxide scale and
foreign matter and, in particular, free from lubricants, unless otherwise specified in product standards.
The finish of the surface shall permit accurate determination of the diagonal length of the indentation.
7.2 Preparation
Surface preparation shall be carried out in such a way as to prevent surface damage, or alteration of the
surface hardness due to excessive heating or cold-working.
Due to the small depth of Knoop hardness indentations, it is essential that special precautions be taken
during preparation. It is recommended to use a polishing/electropolishing technique that is adapted to
the material to be measured.
7.3 Thickness
The thickness of the test piece, or of the layer under test, shall be at least 1/3 times the length of the
diagonal length of the indentation. No deformation shall be visible at the back of the test piece after
the test.
NOTE The depth of the indentation is approximately 1/30 of the diagonal length (0,033 d).
7.4 Support of unstable test pieces
For a test piece of small cross-section or of irregular shape, either a dedicated support should be used
or it should be mounted in a similar manner to a metallographic micro-section in appropriate material
so that it is adequately supported and does not move during the force application.
4 © ISO 2017 – All rights reserved
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SIST EN ISO 4545-1:2018
ISO 4545-1:2017(E)
8 Procedure
8.1 Test temperature
The test is normally carried out at ambient temperature within the limits of 10 °C to 35 °C. If the test
is carried out at a temperature outside this range, it shall be noted in the test report. Tests carried out
under controlled conditions shall be made at a temperature of (23 ± 5) °C.
8.2 Test force
The test forces given in Table 3 are typical. Other test forces may be used. Test forces shall be chosen
that result in indentations with a long diagonal greater than 0,020 mm.
Table 3 — Typical test forces
Test force value, F
Hardness scale
a
N Approximate kgf equivalent
HK 0,001 0,009 807 0,001
HK 0,002 0,019 61 0,002
HK 0,005 0,049 03 0,005
HK 0,01 0,098 07 0,010
HK 0,02 0,196 1 0,020
HK 0,025 0,245 2 0,025
HK 0,05 0,490 3 0,050
HK 0,1 0,980 7 0,100
HK 0,2 1,961 0,200
HK 0,3 2,942 0,300
HK 0,5 4,903 0,500
HK 1 9,807 1,000
HK 2 19,613 2,000
a
Not an SI unit.
8.3 Periodic verification
The periodic verification defined in Annex A shall be performed within a week prior to use for each test
force used but is recommended on the day of use. The periodic verification is recommended whenever
the test force is changed. The periodic verification shall be done whenever the indenter is changed.
8.4 Test piece support
The test piece shall be placed on a rigid support. The support surfaces shall be clean and free from
foreign matter (scales, oil, dirt, etc.). It is important that the test piece lies firmly on the support so that
any displacement that affects the test result cannot occur during the test.
8.5 Focus on test surface
The diagonal measuring system microscope shall be focused so that the specimen surface and the
desired test location can be observed.
NOTE Some testing machines do not require that the microscope be focused on the specimen surface.
© ISO 2017 – All rights reserved 5
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Edge of test piece
SIST EN ISO 4545-1:2018
ISO 4545-1:2017(E)
8.6 Test force application
The indenter shall be brought into contact with the test surface and the test force shall be applied in a
direction perpendicular to the surface, without shock, vibration or overload, until the applied force
attains the specified value. The time from the initial application of the force until the full test force is
+1
reached shall be 7 s .
−5
+1
NOTE 1 The requirements for the time durations are given with asymmetric limits. For example, 7 s
−5
indicates that 7 s is the nominal time duration, with an acceptable range of not less than 2 s (calculated as 7 s – 5 s)
to not more than 8 s (calculated as 7 s + 1 s).
The indenter shall contact the test piece at a velocity of ≤0,070 mm/s.
+1
The duration of the test force shall be 14 s, except for tests on materials whose time-dependent
−4
properties would make this an unsuitable range. For these tests, this duration shall be specified as part
of the hardness designation (see 5.2).
NOTE 2 There is evidence that some materials are sensitive to the rate of straining which causes changes in
the value of the yield strength. The corresponding effect on the termination of the formation of an indentation
can make alterations in the hardness value.
8.7 Prevention of the effect of shock or vibration
[6]
Throughout the test, the testing machine shall be protected from shock or vibration .
8.8 Minimum distance between adjacent indentations
The minimum distance between adjacent indentations and the minimum distance between an
indentation and the edge of the test piece are shown in Figure 3.
The minimum distance between the edge of the test piece and the centre of any indentation oriented
parallel to the edge of the test piece shall be at least 3,5 times the length of the short diagonal of the
indentation. The minimum distance between the edge of the test piece and the centre of any indentation
oriented perpendicular to the edge of the test piece shall be at least equal to the length of the long
diagonal of the indentation.
The minimum distance between the centres of two adjacent indentations, oriented side-by-side,
shall be at least 3,5 times the length of the short diagonal. For indentations oriented end-to-end, the
minimum distance between the centres of two adjacent indents shall be at least twice the length of the
long diagonal. If two indentations differ in size, the minimum spacing shall be based on the diagonal of
the larger indentation.
Edge of test piece
3,5 d
s
2 dd
3,5 d
s
d
s
d
Figure 3 — Minimum distance for Knoop indentations
6 © ISO 2017 – All rights reserved
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SIST EN ISO 4545-1:2018
ISO 4545-1:2017(E)
8.9 Measurement of diagonal length
The
...
SLOVENSKI STANDARD
oSIST prEN ISO 4545-1:2015
01-julij-2015
Kovinski materiali - Preskus trdote po Knoopu - 1. del: Preskusna metoda (ISO/DIS
4545-1:2015)
Metallic materials - Knoop hardness test - Part 1: Test method (ISO/DIS 4545-1:2015)
Metallische Werkstoffe - Härteprüfung nach Knoop - Teil 1: Prüfverfahren (ISO/DIS 4545
-1:2015)
Matériaux métalliques - Essai de dureté Knoop - Partie 1 : Méthode d'essai (ISO/DIS
4545-1:2015)
Ta slovenski standard je istoveten z: prEN ISO 4545-1
ICS:
77.040.10 Mehansko preskušanje kovin Mechanical testing of metals
oSIST prEN ISO 4545-1:2015 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN ISO 4545-1:2015
---------------------- Page: 2 ----------------------
oSIST prEN ISO 4545-1:2015
DRAFT INTERNATIONAL STANDARD
ISO/DIS 4545-1
ISO/TC 164/SC 3 Secretariat: DIN
Voting begins on: Voting terminates on:
2015-04-23 2015-07-23
Metallic materials — Knoop hardness test —
Part 1:
Test method
Matériaux métalliques — Essai de dureté Knoop —
Partie 1: Méthode d’essai
ICS: 77.040.10
ISO/CEN PARALLEL PROCESSING
This draft has been developed within the International Organization for
Standardization (ISO), and processed under the ISO lead mode of collaboration
as defined in the Vienna Agreement.
This draft is hereby submitted to the ISO member bodies and to the CEN member
bodies for a parallel five month enquiry.
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ISO/DIS 4545-1:2015(E)
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oSIST prEN ISO 4545-1:2015
ISO/DIS 4545-1:2015(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Principle . 1
4 Symbols and abbreviated terms . 2
5 Testing Machine . 3
6 Test piece . 4
7 Procedure. 4
8 Uncertainty of the results . 6
9 Test report . 6
Annex A (normative) Procedure for periodic checking of the testing machine by the user .8
Annex B (informative) Uncertainty of the measured hardness values .10
Annex C (informative) Knoop Hardness Measurement Traceability .16
Annex D (informative) CCM - Working Group on Hardness .20
Bibliography .21
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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 on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
ISO 4545-1 was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals, Subcommittee
SC 3, Hardness testing.
This second edition cancels and replaces the first (ISO 4545-1:2005), which has been technically revised.
ISO 4545 consists of the following parts, under the general title Metallic materials — Knoop hardness test:
— Part 1: Test method;
— Part 2: Verification and calibration of testing machines;
— Part 3: Calibration of reference blocks;
— Part 4: Table of hardness values.
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oSIST prEN ISO 4545-1:2015
DRAFT INTERNATIONAL STANDARD ISO/DIS 4545-1:2015(E)
Metallic materials — Knoop hardness test —
Part 1:
Test method
1 Scope
This part of ISO 4545 specifies the Knoop hardness test method for metallic materials, for test forces from
0,0098 07 N to 19,614 N. The method is recommended only for indentations with diagonals ≥ 0,020 mm.
NOTE Special considerations for Knoop testing of metallic coatings can be found in ISO 4516 (see [7] in
Bibliography).
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 4545-2, Metallic materials — Knoop hardness test — Part 2: Verification and calibration of testing
machines
ISO 4545-3, Metallic materials — Knoop hardness test — Part 3: Calibration of reference blocks
ISO 4545-4, Metallic materials — Knoop hardness test — Part 4: Table of hardness values
3 Principle
A diamond indenter, in the form of a rhombic-based pyramid with angles α and β between opposite edges
respectively equal to 172,5° and 130° at the vertex, is forced into the surface of a test piece followed by
measurement of the long diagonal, d, of the indentation remaining in the surface after removal of the
test force, F (see Figures 1 and 2).
Figure 1 — Principle of the test and indenter geometry
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Figure 2 — Knoop indentation
The Knoop hardness is proportional to the quotient obtained by dividing the test force by the projected
area of the indentation, which is assumed to be a rhombic-based pyramid, and having at the vertex the
same angles as the indenter.
4 Symbols and abbreviated terms
4.1 See Table 1 and Figures 1 and 2.
4.2 The following is an example of the designation of Knoop hardness.
EXAMPLE
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Table 1 — Symbols and abbreviated terms
Symbol/
abbreviated Designation
term
F Test force, in newtons (N)
d Length of the long diagonal, in millimetres
c Indenter constant, relating projected area of the indentation to the square of the length of the
long diagonal
β
tan
2
Indenter constant, c= , c = 0,070 28
α
2tan
2
where α and β are the angles between the opposite edges at the vertex of the diamond pyramid
(see Figure 1)
HK
Test force
Knoop hardness = Constant ´
Projectedareaofindentation
F F
= 0,102×=1,451
22
cd d
1
NOTE Constant = 0,,102= where 9,806 65 is the conversion factor from kgf to N.
9,806 65
5 Testing Machine
5.1 Testing machine, shall be capable of applying a predetermined force or forces within the desired
range of test forces, in accordance with ISO 4545-2.
5.2 Indenter, shall be a diamond in the shape of a rhombic-based pyramid, as specified in ISO 4545-2.
5.3 Diagonal measuring system, shall satisfy the specifications in ISO 4545-2.
The optical portion of the diagonal measuring system should have Köhler illumination. See Annex A of
ISO 4545-3.
Many older objectives lenses are nonlinear towards the edge of the field of view. Therefore, magnifications
should be provided so that the diagonal can be enlarged to greater than 25 % but less than 75 % of the
maximum possible optical field of view.
NOTE Systems using a camera for measurement may use 100 % of the camera’s field of view provided they
are designed to consider the 75 % and any other field of view limitations of the optical system.
The resolution required of the diagonal measuring system depends on the size of the smallest indentation
to be measured.
The scale of the measuring system shall be graduated to permit estimation of the diagonals of the
indentation in accordance with Table 2.
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Table 2 — Resolution of the measuring system
Diagonal length
d Resolution of the measuring system
mm
d < 0,040 0,000 2 mm
0,040 ≤ d 0,5 % of d
NOTE The diagonal length of the indentation determines the necessary magnification V of
the measuring system according to the following condition:
V × d ≥ 14 mm
For indentation diagonals d < 0,035 mm this condition may not be fulfilled, but the
magnification should be at least 400x.
6 Test piece
6.1 The test shall be carried out on a polished surface, which is smooth and even, free from oxide
scale and foreign matter and, in particular, free from lubricants, unless otherwise specified in product
standards. The finish of the surface shall permit accurate determination of the diagonal length of the
indentation.
6.2 Preparation shall be carried out in such a way that any pull out of materials or alteration of the
surface hardness, due to excessive heating or cold work, for example, is minimized.
6.3 Due to the small depth of Knoop hardness indentations, it is essential that special precautions
be taken during preparation. It is recommended to use a polishing/electropolishing technique that is
adapted to the material to be measured.
6.4 The thickness of the test piece or of the layer under test shall be at least 1/3 times the length of the
diagonal length of the indentation. No deformation shall be visible at the back of the test piece after the
test.
6.5 For test pieces of small cross-section or of irregular shape, it may be necessary to provide some
form of additional support, for example, mounting in plastic material. The test piece shall be adequately
supported by the mounting medium so that the test piece does not move during the force application.
7 Procedure
7.1 The test is normally carried out at ambient temperature within the limits of 10 °C to 35 °C. . If the
test is carried out at a temperature outside this range, it shall be noted in the test report. Tests carried out
under controlled conditions shall be made at a temperature of (23 ± 5) °C.
7.2 The test forces given in Table 3 are typical. Other test forces may be used. Test forces should be
chosen that result in indentations with a long diagonal greater than 0,020 mm.
7.3 The daily verification defined in Annex A shall be performed before the first test of each week
for each test force used but is recommended daily. The daily verification is recommended whenever the
test force is changed. The daily verification shall be done whenever the indenter is changed. The daily
verification should be done within 200 HK of the expected hardness level to be tested.
7.4 The test piece shall be placed on a rigid support. The support surfaces shall be clean and free from
foreign matter (scales, oil, dirt, etc.). It is important that the test piece lies firmly on the support so that
displacement cannot occur during the test.
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7.5 Focus the diagonal measuring system microscope so that the specimen surface can be observed.
NOTE Some testers do not require that the microscope be focused on the specimen surface.
7.6 Bring the indenter into contact with the test surface and apply the test force in a direction
perpendicular to the surface, without shock, vibration or overload, until the applied force attains the
specified value. The time from the initial application of the force until the full test force is reached shall be
+1
7 s .The indenter shall contact the test piece at a velocity between 0.015 and 0.070 mm/s.
−5
+1
The duration of the test force shall be 14 s, except for tests on materials whose time-dependent
−4
properties would make this an unsuitable range. For these tests, this duration shall be specified as part
of the hardness designation (see EXAMPLE in 4.2).
+1
NOTE The requirements for the time durations are given with asymmetric limits. For example, 7 s
−5
indicates that 7 s is the nominal time duration, with an acceptable range of not less than 2 s (7 s – 5 s) to not more
than 8 s (7 s + 1 s).
Table 3 — Typical test forces
Test force value, F
Hardness scale
a
N approximate kgf equivalent
HK 0,001 0,0098 07 0,001
HK 0,002 0,0196 1 0,002
HK 0,005 0,0490 3 0,005
HK 0,01 0,098 07 0,010
HK 0,02 0,196 1 0,020
HK 0,025 0,245 2 0,025
HK 0,05 0,490 3 0,050
HK 0,1 0,980 7 0,100
HK 0,2 1,961 0,200
HK 0,3 2,942 0,300
HK 0,5 4,903 0,500
HK 1 9,807 1,000
HK 2 19,614 2,000
a
Not an SI unit.
7.7 Throughout the test, the apparatus shall be protected from shock or vibration. (See [6] in
Bibliography)
7.8 The minimum distance between the limit of any indentation and the edge of the test piece shall be
at least 3 times the short diagonal of the indentation.
7.9 The minimum distance between the limits of two adjacent indentations, oriented side-by-side,
shall be at least 2,5 times the length of the short diagonal. For indentations oriented end-to-end, the
minimum distance between the limits of two adjacent indents shall be at least one time the length of the
long diagonal. If two indentations differ in size, the minimum spacing shall be based on the short diagonal
of the larger indentation.
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7.10 The length of the long diagonal shall be measured and used for the calculation of the Knoop
hardness. For all tests, the perimeter of the indentation shall be clearly defined in the field of view of the
microscope.
NOTE 1 For an indentation with a long diagonal less than 0.020 mm, the increase of the uncertainty has to be
considered.
NOTE 2 In general, decreasing the test force increases the scatter of the results of the measurements. The
accuracy of the determination of the long diagonal length is unlikely to be better than ± 0,001 mm.
Magnifications should be selected so that the diagonal can be enlarged to greater than 25 %, but less
than 75 % of the maximum possible optical field of view, see 5.3.
7.11 The Knoop hardness value shall be calculated by the formula given in Table 1, or by using the tables
given in ISO 4545-4.
7.12 Divide the long diagonal at the point of intersection with the short diagonal. If the length of one
segment differs by more than 10 % from the other segment, check the parallelism between the supporting
plane and the measuring plane of the specimen and eventually the alignment of the indenter to the
specimen. Test results with deviations greater than 10 % should be discarded.
8 Uncertainty of the results
[1]
A complete evaluation of the uncertainty should be done according to ISO/IEC Guide 98-3 .
Independent of the type of sources, for hardness there are two possibilities for the determination of the
uncertainty.
— One possibility is based on the evaluation of all relevant sources appearing during a direct calibration.
[2]
As a reference, an EA guideline is available.
[3-5]
— The other possibility is based on indirect calibration using a hardness reference block (see in
the Bibliography). A guideline for the determination is given in Annex B.
It may not always be possible to quantify all the identified contributions to the uncertainty. In this case,
an estimate of type A standard uncertainty may be obtained from the statistical analysis of repeated
indentations into the test piece. Care should be taken if standard uncertainties of type A and B are
summarized, that the contributions are not counted twice (see Clause 4 of ISO/IEC Guide 98-3).
9 Test report
The laboratory shall record at least the following information and that information shall be included in
the test report unless otherwise agreed by the parties concerned:
a) a reference to this part of ISO 4545;
b) all information necessary for identification of the test piece;
c) the hardness result obtained in the format defined in 4.2;
d) all operations not specified in this part of ISO 4545 or regarded as optional;
e) details of any circumstances, that may have affected the result;
f) the temperature of the test, if it is outside the ambient range specified in 7.1.
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There is no general process of accurately converting Knoop hardness values into other scales of
hardness or into tensile strength. Such conversions, therefore, should be avoided, unless a reliable basis
[8]
for conversion can be obtained by comparison tests (see also ISO 18265 ).
NOTE A strict comparison of hardness values is only possible at identical test forces.
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Annex A
(normative)
Procedure for periodic checking of the testing machine by the user
The indenter to be used for the daily verification shall be the same as used for testing.
Before performing the daily verification, the diagonal measuring system should be indirectly verified
using one of the reference indentations on a hardness reference block calibrated according to ISO 4545-3.
The measured indentation length shall agree with the certified value to within the greater of 1,0 %
and 0,0004 mm. If the diagonal measuring system fails this test a second reference indentation may be
measured. If the diagonal measuring system continues to fail this test, the diagonal measuring system
shall be adjusted or repaired and undergo direct and indirect verification according to ISO 4545-2.
Only the calibrated surface of the hardness reference block is to be used for testing.
At least two hardness readings shall be made on a hardness reference block calibrated in accordance to
ISO 4545-3 on the scale and at the approximate hardness level at which the machine will be used. The
indentations shall be uniformly distributed over the surface of the standardized test block. The machine
is regarded as satisfactory if the percent bias, b , for each reading does not exceed the limits shown in
rel
Table A.1.
The percent bias b is calculated by the following equation:
rel
HH−
CRM
b =⋅100 (A.1)
rel
H
CRM
where
H is the hardness value corresponding to the hardness reading taken;
H is the certified hardness of the reference block used.
CRM
The maximum percent bias, b , of the testing machine, shall not exceed the values given in Table A1.
rel
If the testing machine fails this test, verify that the indenter, the specimen holder and machine are in
good working condition and repeat the verification. If the machine continues to fail the daily verification,
an indirect verification according to ISO 4545-2 shall be performed. A record of the daily verification
results should be maintained over a period of time and used to measure reproducibility and monitor
drift of the machine.
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Table A.1 — Maximum permissible percentage bias
Maximum permissible percentage biasb , of the hardness testing machine, %
rel
Hardness
Hardness, HK
scale
50 100 150 200 250 300 350 400 450 500 600 700 800 900 1000 1500
HK 0,01 4,2 4,2 4,2 4,2 4,4 4,8 5,2
HK 0,02 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,8 4,8 5,2
HK 0,025 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,3 4,3 4,6 5,0
HK 0,05 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,8
HK 0,1 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2
HK 0,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2
HK 0,3 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2
HK 0,5 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2
HK 1 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2
HK 2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2 4,2
NOTE 1 Values are not given when the length of the indentation diagonal is less than 0,020 mm.
NOTE 2 For intermediate values, the maximum permissible error may be obtained by interpolation.
NOTE 3 The values are based on a maximum permissible error of 0,000 5 mm or 2 % of the diagonal length of indentation,
whichever is the greater.
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Annex B
(informative)
Uncertainty of the measured hardness values
B.1 General requirements
Measurement uncertainty analysis is a useful tool to help determine sources of error and to understand
differences in test results. This annex gives guidance on uncertainty estimation but the methods
contained are for information only, unless specifically instructed otherwise by the customer. Most
product specifications have tolerances that have been developed over the past years based mainly on
the requirements of the product but also, in part, on the performance of the machine used to make the
hardness measurement. These tolerances therefore incorporate a contribution due to the uncertainty
of the hardness measurement and it would be inappropriate to make any further allowance for this
uncertainty by, for example, reducing the specified tolerance by the estimated uncertainty of the
hardness measurement. In other words, where a product specification states that the hardness of an
item shall be higher or lower than a certain value, this should be interpreted as simply specifying that
the calculated hardness value(s) shall meet this requirement, unless specifically stated otherwise in the
product standard. However, there may be special circumstances where reducing the tolerance by the
measurement uncertainty is appropriate. This should only be done by agreement of the parties involved.
The approach for determining uncertainty presented in this annex considers only those uncertainties
associated with the overall measurement performance of the hardness testing machine with respect
to the hardness reference blocks. These performance uncertainties reflect the combined effect to all
the separate uncertainties (indirect verification). Because of this approach, it is important that the
individual machine components are operating within the tolerances. It is strongly recommended that
this procedure be applied for a maximum of one year after the successful passing of a direct verification.
Annex C shows the four-level structure of the metrological chain necessary to define and disseminate
hardness scales. The chain starts at the international level using international definitions of the
various hardness scales to carry out international intercomparisons. A number of primary hardness
standard machines at the national level “produce” primary hardness-reference blocks for the calibration
laboratory level. Naturally, direct calibration and the verification of these machines should be at the
highest possible accuracy.
B.2 General procedure
The procedure calculates a combined uncertainty u by the Root-Squared-Sum-Method (RSS) out of the
H
different sources given in Table B.1. The expanded uncertainty, U, is derived from u by multiplying with
H
the coverage factor k = 2. Table B.1 contains all symbols and their designation.
The bias, b, of a hardness testing machine (also named “error”), which is derived from the difference
between
— the certified calibration value of the hardness reference block used, and
— the mean hardness value of the five indentations made in this block during calibration of the
hardness testing machine,
(see ISO 4545-2) can be implemented in different ways into the determination of uncertainty.
Two methods are given for determining the uncertainty of hardness measurements:
— Method 1 (M1): accounts for the systematic bias of the hardness machine in two different ways;
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— Method 2 (M2): allows the determination of uncertainty without having to consider the magnitude
of the systematic bias.
[1, 2]
Additional information on calculating hardness uncertainties can be found in the literature (see in
the Bibliography).
NOTE 1 This uncertainty approach makes no allowance for any possible drift in the machine performance
subsequent to its last calibration, as it assumes that any such changes will be insignificant in magnitude. As such,
most of this analysis could be performed immediately after the machine’s calibration and the results included in
the machine’s calibration certificate.
NOTE 2 In this annex, the abbreviation “CRM” stands for “Certified Reference Mat
...
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