SIST EN ISO 18265:2004
(Main)Metallic materials - Conversion of hardness values (ISO 18265:2003)
Metallic materials - Conversion of hardness values (ISO 18265:2003)
ISO 18265:2003 specifies the principles of the conversion of hardness values and gives general information on the use of conversion tables.
The conversion tables apply to
unalloyed and low-alloy steels and cast iron;
steels for quenching and tempering;
cold working steels;
high speed steels;
hardmetals;
non-ferrous metals and alloys.
Metallische Werkstoffe - Umwertung von Härtewerten (ISO 18265:2003)
Diese Norm legt Grundsätzliches zur Umwertung von Härtewerten fest und Allgemeines zur Anwendung von Umwertungstabellen.
Die in den Anhängen A bis F dieser Norm enthaltenen Umwertungstabellen gelten für
- unlegierte und niedriglegierte Stähle und Stahlguss,
- Vergütungsstähle,
- Kaltarbeitsstähle,
- Schnellarbeitsstähle,
- verschiedene Hartmetallsorten,
- Nichteisenmetalle und -legierungen.
ANMERKUNG Die Umwertungstabellen in den Anhängen B bis E dieser Norm basieren auf experimentellen Ergebnissen, die mittels Regressionsanalyse ausgewertet wurden. Für die Umwertungstabelle im Anhang A dieser Norm lagen für diese Auswertung nicht genügend Messergebnisse vor.
Matériaux métalliques - Conversion des valeurs de dureté (ISO 18265:2003)
L'ISO 18265:2003 spécifie les principes de conversion des valeurs de dureté et fournit des informations générales sur l'utilisation des tables de conversion.
Les tables de conversion s'appliquent aux aciers non alliés et faiblement alliés et à la fonte, aux aciers pour trempe et revenu, aux aciers pour formage à froid, aux aciers rapides, aux métaux durs et aux métaux et alliages non ferreux.
Kovinski materiali – Pretvorbe vrednosti trdote (ISO 18265:2003)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 18265:2004
01-junij-2004
Kovinski materiali – Pretvorbe vrednosti trdote (ISO 18265:2003)
Metallic materials - Conversion of hardness values (ISO 18265:2003)
Metallische Werkstoffe - Umwertung von Härtewerten (ISO 18265:2003)
Matériaux métalliques - Conversion des valeurs de dureté (ISO 18265:2003)
Ta slovenski standard je istoveten z: EN ISO 18265:2003
ICS:
77.040.10 Mehansko preskušanje kovin Mechanical testing of metals
SIST EN ISO 18265:2004 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 18265:2004
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SIST EN ISO 18265:2004
EUROPEAN STANDARD
EN ISO 18265
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2003
ICS 77.040.01
English version
Metallic materials - Conversion of hardness values (ISO
18265:2003)
Matériaux métalliques - Conversion des valeurs de dureté Metallische Werkstoffe - Umwertung von Härtewerten (ISO
(ISO 18265:2003) 18265:2003)
This European Standard was approved by CEN on 3 October 2003.
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,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, 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
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 18265:2003 E
worldwide for CEN national Members.
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SIST EN ISO 18265:2004
EN ISO 18265:2003 (E)
CORRECTED 2003-12-03
Foreword
This document (EN ISO 18265:2003) has been prepared by Technical Committee ISO/TC 164
"Mechanical testing of metals" in collaboration with 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 May 2004, and conflicting national standards
shall be withdrawn at the latest by May 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, Czech
Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and
the United Kingdom.
Endorsement notice
The text of ISO 18265:2003 has been approved by CEN as EN ISO 18265:2003 without any
modifications.
NOTE Normative references to International Standards are listed in Annex ZA (normative).
2
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SIST EN ISO 18265:2004
EN ISO 18265:2003 (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 6506-1 1999 Metallic materials - Brinell EN ISO 6506-1 1999
hardness test - Part 1: Test
method
ISO 6507-1 1997 Metallic materials - Vickers EN ISO 6507-1 1997
hardness test - Part 1: Test
method
ISO 6507-2 1997 Metallic materials - Vickers EN ISO 6507-2 1997
hardness test - Part 2: Verification
of testing machines
ISO 6508-1 1999 Metallic materials - Rockwell EN ISO 6508-1 1999
hardness test - Part 1: Test
method (scales A, B, C, D, E, F,
G, H, K, N, T)
ISO 6508-2 1999 Metallic materials - Rockwell EN ISO 6508-2 1999
hardness test - Part 2: Verification
and calibration of testing
machines (scales A, B, C, D, E, F,
G, H, K, N, T)
ISO 7500-1 1999 Metallic materials - Verification of EN ISO 7500-1 1999
static uniaxial testing machines -
Part 1: Tension/compression
testing machines
ISO 9513 1999 Metallic materials - calibration of EN ISO 9513 2002
extensometers used in uniaxial
testing
3
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SIST EN ISO 18265:2004
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SIST EN ISO 18265:2004
INTERNATIONAL ISO
STANDARD 18265
First edition
2003-11-01
Metallic materials — Conversion of
hardness values
Matériaux métalliques — Conversion des valeurs de dureté
Reference number
ISO 18265:2003(E)
©
ISO 2003
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SIST EN ISO 18265:2004
ISO 18265:2003(E)
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ii © ISO 2003 — All rights reserved
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SIST EN ISO 18265:2004
ISO 18265:2003(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references. 1
3 Principles of conversion . 2
4 Application of conversion tables . 2
4.1 General. 2
4.2 Converting values. 6
4.3 Designation of conversion results . 8
4.4 Notes on use of conversion tables . 9
Annex A (informative) Conversion table for unalloyed, low-alloy steels and cast iron . 10
Annex B (informative) Conversion tables for steels for quenching and tempering. 15
Annex C (informative) Conversion tables for cold working steels. 33
Annex D (informative) Conversion tables for high speed steels. 44
Annex E (informative) Conversion tables for hardmetals . 56
Annex F (informative) Conversion tables for non-ferrous metals and alloys . 60
Bibliography . 73
© ISO 2003 — All rights reserved iii
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SIST EN ISO 18265:2004
ISO 18265:2003(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 18265 was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals, Subcommittee
SC 3, Hardness testing.
iv © ISO 2003 — All rights reserved
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SIST EN ISO 18265:2004
ISO 18265:2003(E)
Introduction
The hardness conversion values given in Table A.1 were obtained in interlaboratory tests by the Verein
Deutscher Eisenhüttenleute (VDEh) (German Iron and Steel Institute) using verified and calibrated hardness
testing machines. Statistically reliable information cannot be given on the uncertainty of these values because
the test conditions were not reproducible, and the number of results used to calculate the mean hardness
values is not known. The conversion values in Table A.1 are in accordance with the information presented in
IC No. 3 (1980) and IC No. 4 (1982) of the European Coal and Steel Community, as well as in ISO 4964:1984
and ISO/TR 10108:1989.
Annexes C, D and E contain — in a revised format — the extensive results on the conversion of hardness
values presented in TGL 43212/02 to 43212/04, standards published by the former East German standards
body, the Amt für Standardisierung, Meßwesen und Warenprüfung (ASMW). The values presented in
Annex B had also been determined by the ASMW, but were published in a report of the Physikalisch-
[1]
Technische Bundesanstalt (PTB) , the German national institute for science and technology, not in a TGL
standard.
The converted hardness values in the above-mentioned TGL standards were obtained in statistically reliable
hardness and tensile tests. The hardness tests were performed using ASMW normal testing machines on
plane-parallel, polished specimens of various materials in different heat treatment conditions. Tensile strength
was tested on machines whose force measuring and extension measuring systems had been calibrated
immediately before testing. The tensile test method used is equivalent to that specified in ISO 6892, and the
calibration procedures conform with those specified in ISO 7500-1 and ISO 9513.
Users of this International Standard should take note of Clause 3, especially the concluding warning.
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SIST EN ISO 18265:2004
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SIST EN ISO 18265:2004
INTERNATIONAL STANDARD ISO 18265:2003(E)
Metallic materials — Conversion of hardness values
1 Scope
This International Standard specifies the principles of the conversion of hardness values and gives general
information on the use of conversion tables.
The conversion tables in Аnnexes A to F apply to
unalloyed and low-alloy steels and cast iron;
steels for quenching and tempering;
cold working steels;
high speed steels;
hardmetals;
non-ferrous metals and alloys.
NOTE The conversion tables in Annexes B to E are based on empirical results which were evaluated by means of
regression analysis. Such analysis was not possible in the case of the values given in Annex A because a sufficient
number of results was not available.
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 6506-1:1999, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6507-1:1997, Metallic materials — Vickers hardness test — Part 1: Test method
ISO 6507-2:1997, Metallic materials — Vickers hardness test — Part 2: Verification of testing machines
ISO 6508-1:1999, Metallic materials — Rockwell hardness test — Part 1: Test method (scales A, B, C, D, E, F,
G, H, K, N, T)
ISO 6508-2:1999, Metallic materials — Rockwell hardness test — Part 2: Verification and calibration of testing
machines (scales A, B, C, D, E, F, G, H, K, N, T)
ISO 6892:1998, Metallic materials — Tensile testing at ambient temperature
1)
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
ISO 9513:1999, Metallic materials — Calibration of extensometers used in uniaxial testing
1)
To be published. (Revision of ISO 7500-1:1999)
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SIST EN ISO 18265:2004
ISO 18265:2003(E)
3 Principles of conversion
Hardness testing is a form of materials testing that provides information on the mechanical properties of a
material with limited destruction of the specimen and within a relatively short period of time. In practice, it is
often desirable to use hardness results to draw conclusions on the tensile strength of the same material if
tensile testing is too involved or the piece to be examined is not to be destroyed.
Since the means of loading in hardness testing is considerably different from that in tensile testing, it is not
possible to derive a reliable functional relationship between these two characteristic values on the basis of a
model. Nevertheless, hardness values and tensile strength values are positively correlated, and so it is
possible to draw up empirical relationships for limited applications.
Often it is necessary to check a given hardness value against a value gained by a different test method. This
is especially the case if only a certain method can be used due to the particular specimen or coating thickness,
the size of the object to be tested, surface quality, or the availability of hardness testing machines.
Conversion of hardness values to tensile values makes it possible to carry out hardness measurement in
place of the measurement of tensile strength taking into account that these tensile strength values must be
seen as being the least reliable form of conversion. Likewise, with conversion between hardness scales, a
hardness value can be replaced with a value obtained using the desired method.
NOTE Sometimes a conversion relationship is drawn on a single-case basis to gain information on properties other
than hardness, most often to obtain a good estimate of tensile strength. Special relationships are sometimes also drawn
for hardness-to-hardness conversions. This may be done as long as the following conditions are fulfilled.
The hardness test method is only used internally, and the results obtained not be compared with those of other
methods, or the details of the test procedure are defined precisely enough so that results can be reproduced by
another laboratory or at another time.
The conversion tables used have been derived from a sufficiently large number of parallel experiments using both
scales and carried out on the material in question.
Complaints may not be made on the basis of converted values.
Converted results are expressed in such a manner that it is clear which method was used to determine the original
hardness value.
WARNING — In practice, an attempt is often made to establish a strong relationship between the
original and converted values without taking into consideration the characteristics of the material
under test. As Figures 1 and 2 show, this is not possible. Therefore, users of this International
Standard should ensure that all conditions for conversion are met (see also [2] and [3]).
4 Application of conversion tables
4.1 General
Conversion from one hardness value to another, or from a hardness value to a tensile strength value, involves
uncertainties which must be taken into account. Extensive investigations have shown that it is not possible to
establish universally applicable conversion relationships between hardness values obtained by different
methods, no matter how carefully the tests had been carried out. This lies in the fact that there is a complex
relationship between the indentation behaviour of a material and its elasticity. For this reason, the given
conversion relationship provides greater equivalence the more similarity there is between the elasticity of the
tested material and that of the material used to establish the relationship. Likewise, a better equivalence can
be expected for methods with similar indentation processes (i.e. where the differences in the force application-
indentation procedures and the test parameters is minimal). Therefore, conversion from hardness values to
tensile values must be seen as being the least reliable form of conversion.
NOTE In many cases, the yield strength or the 0,2 % proof strength provides information on the elastic behaviour of a
material.
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SIST EN ISO 18265:2004
ISO 18265:2003(E)
X Hardness, HV 30
Y Tensile strength, R , MPa
m
Key
1 untreated, soft annealed, normalized
2 quenched and tempered
Figure 1 —HV 30/R curves for quenching and tempering steels in various heat treatment conditions
m
It should be noted that each hardness determination is only applicable to the immediate area of the
indentation. Where hardness varies, e.g. at an increasing distance from the surface, Brinell or Vickers
hardness values, or even tensile strength values can deviate from the converted values solely as a result of
the different rate of elongation within the area under consideration.
Hardness values should only be converted when the prescribed test method cannot be used, e.g. because a
suitable machine is not available, or if the required samples cannot be taken. A suitable test method can be
selected with the aid of Figures 3 and 4. Values obtained by conversion may only be taken as the basis of
complaints if so agreed in the delivery contract.
If hardness or tensile strength values are determined by conversion in accordance with this International
Standard, this shall be stated, as shall the hardness test method used (see ISO 6506-1, ISO 6507-1,
ISO 6508-1).
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SIST EN ISO 18265:2004
ISO 18265:2003(E)
X Hardness, HV 30
Y Tensile strength, R , MPa
m
Key
1 R /R = 0,45 to 0,59 4 R /R = 0,70 to 0,79 heat treated
e m e m
2 R /R = 0,60 to 0,69 5 R /R = 0,80 to 0,89
e m e m
3 R /R = 0,70 to 0,79 normal annealed 6 R /R = 0,90 to 0,99
e m e m
Figure 2 — Mean HV 30/R curves for quenching and tempering steels with different R /R ratios
m e m
The basis of conversion shall be the mean of at least three individual hardness values.
To ensure an acceptable uncertainty of measurement, the specimen surfaces shall be machine-finished.
The uncertainties of the values given in the conversion tables here comprise the confidence interval of the
hardness conversion curves calculated by means of regression analysis, and the uncertainty of the hardness
or tensile strength value to be converted. The confidence interval of the regression function is a parameter
that cannot be influenced by the user and is calculated as a function of hardness.
The uncertainty associated with the hardness values to be converted is influenced by the repeatability of the
testing machine, the quality of the specimen surface, the uniformity of the specimen's hardness and the
number of indentations used to determine hardness. It is thus dependent on the test conditions of the person
doing the conversion. This conversion is to be carried out on the basis of the tables given in this International
Standard for various groups of materials. These tables give hardness values for various scales and, in some
cases, the relevant tensile strength.
When only comparing the values in these tables without actually carrying out hardness testing, the uncertainty
of the converted value is reduced to the confidence interval of the calculated hardness conversion curve.
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SIST EN ISO 18265:2004
ISO 18265:2003(E)
When using the tables, it is not significant which value is taken as the measured value and which as the
converted one.
The determination of the uncertainty of converted values, as well as the specification of a permissible level of
uncertainty may be agreed upon, in which case the converted values are to be established on the basis of the
mean of five individual values.
X Vicker hardness, HV 30
Y Rockwell hardness
1
Y Brinell hardness
2
Key
1 non-ferrous metal
2 steel
3 hardmetal
NOTE This figure is intended only as an aid in selecting an alternative test method and is not to be used for
conversion purposes.
a
Determined with a steel ball (HBS).
b
Determined with a hardmetal ball (HBW).
Figure 3 — Various hardness scales compared to the Vickers scale
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SIST EN ISO 18265:2004
ISO 18265:2003(E)
X Brinell hardness/Vicker hardness
1
X Rockwell hardness, (according to its different scales)
2
Y Indentation depth, µm
Key
1 HB10/1 000
2 HB10/500 and HB 5/250
3 HB5/125 and HB 2,5/62,5
4 HB2,5/62,5
Figure 4 — Indentation depth as a function of hardness for various test methods
4.2 Converting values
4.2.1 Limits of error
Depending on the measurement conditions in practice, measured value/converted value pairs (e.g. HV/HRC,
HRC/HV, HRA/HRN, HB/R ) can be taken from the tables in Annexes B to F. Essential criteria which should
m
be taken into account when selecting a hardness test method are discussed in this clause.
The example below illustrates the conversion of values together with their limits of error using Table C.2.
Given hardness value: (300 ± 30) HV
Desired scale: HRC
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SIST EN ISO 18265:2004
ISO 18265:2003(E)
Converted values from table: 270 HV ≙ 26,9 HRC
300 HV ≙ 31,0 HRC
330 HV ≙ 34,6 HRC
+3,6
The converted value, 31 HRC, for the nominal value 300 HV no longer represents the mean of the upper
−4,1
and lower limits in HRC because of the nonlinear relationship between HV and HRC values (see Figure 5).
The confidence interval of the hardness conversion curve may be disregarded for such estimations.
X HV
Y HRC
Figure 5 — Shift of the nominal value when converting hardness values
4.2.2 Uncertainty
The uncertainty of a converted value should be taken from the curves associated with the conversion table
used, as shown in the figures in Annexes B to E for various types of material.
The families of curves given in the annexes represent the uncertainty, u, for a probability level of 95 % as a
function of the hardness value H for various reproducibility limits, R. (H is the corrected arithmetic mean
K K
of five individual values.) The curves have been arranged so that interpolation between neighbouring curves is
possible. The reproducibility, R, is to be calculated on the basis of five measurements as shown in 4.4.2 for
various hardness test methods.
The uncertainty curves only take into account the effects of the random errors of the measured value on the
converted value. However, they do not take into account the systematic error of the testing machine used, as
this can lead to exceedingly high errors in the converted result, even if the systematic error lies within the
permissible range specified for the machine; this is explained in 4.4. For this reason, hardness testing
machines shall be verified, using calibrated blocks, at least within the time interval specified in the relevant
standards. The systematic error determined in this manner is to be compensated by correcting the measured
mean hardness value. This is especially important in the case of Rockwell hardness testing. Figure 6
illustrates the determination of the uncertainty, u, of a converted hardness value (dashed line) according to the
example below.
EXAMPLE
Measured, corrected mean hardness H 500 HV
K
Converted value as in Annex C 49,5 HRC
Calculated reproducibility limit, R 2,0 %
Uncertainty of converted value, u ± 0,7 HRC
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SIST EN ISO 18265:2004
ISO 18265:2003(E)
X H in HV
K
Y u in HRC
Figure 6 — An example of the determination of uncertainty of a converted hardness value
4.3 Designation of conversion results
Conversion results shall be reported in a manner that clearly indicates which method was used to determine
the original hardness value. In addition, the relevant annex to this International Standard or the table used
shall be given.
EXAMPLE 1
EXAMPLE 2 If it is agreed that the uncertainty of the converted value is to be given, this shall be included in the result
as follows:
EXAMPLE 3 Conversions into tensile strength values shall be expressed as follows:
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SIST EN ISO 18265:2004
ISO 18265:2003(E)
4.4 Notes on use of conversion tables
4.4.1 Selection of alternative hardness test methods
4.4.1.1 In Figure 3 hardness scales for non-ferrous metals, hardmetals and selected steels are compared.
The relationship of each scale to the Vickers scale is illustrated, and by comparison with Rockwell and Brinell
scales (ordinates), information is gained as to the hardness ranges covered by each method. This figure is
intended solely as an aid to selection and is not to be used for conversion purposes.
4.4.1.2 Figure 4 shows indentation depths as a function of hardness for various test methods. This
should facilitate selection of a suitable test method on the basis of specimen or coating thickness.
4.4.1.3 Another criterion for selecting an alternative hardness test method is the uncertainty of the
conversion results. Since this can vary greatly, the uncertainty curves given in this International Standard
should also be used to determine which combination of methods is optimal for the application in question.
4.4.2 Calculating the reproducibility limit, R
The reproducibility limit, R, expressed as a percentage, shall be calculated for the different hardness test
methods as shown in equations (1) to (3).
For HRB and HRF testing:
HH−
max min
R=× 100 (1)
130 − H
For HRC, HRA, HRD, HRN and HRT testing:
HH−
max min
R=× 100 (2)
100 − H
where
H , H are the highest and lowest measured hardness values;
max min
H is the mean of measured hardness values.
For HV, Vickers
...
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