SIST EN ISO 18265:2014

SLOVENSKI STANDARD
01-junij-2014
1DGRPHãþD
SIST EN ISO 18265:2004
Kovinski materiali - Pretvorbe vrednosti trdote (ISO 18265:2013)
Metallic materials - Conversion of hardness values (ISO 18265:2013)
Metallische Werkstoffe - Umwertung von Härtewerten (ISO 18265:2013)
Matériaux métalliques - Conversion des valeurs de dureté (ISO 18265:2013)
Ta slovenski standard je istoveten z: EN ISO 18265:2013
ICS:
77.040.10 Mehansko preskušanje kovin Mechanical testing of metals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 18265
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2013
ICS 77.040.10 Supersedes EN ISO 18265:2003
English Version
Metallic materials - Conversion of hardness values (ISO
18265:2013)
Matériaux métalliques - Conversion des valeurs de dureté Metallische Werkstoffe - Umwertung von Härtewerten (ISO
(ISO 18265:2013) 18265:2013)
This European Standard was approved by CEN on 3 August 2013.

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.

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Kingdom.
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© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 18265:2013: E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
This document (EN ISO 18265:2013) 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text or by endorsement, at the latest by April 2014, and conflicting national standards shall be withdrawn at the
latest by April 2014.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 18265:2003.
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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 18265:2013 has been approved by CEN as EN ISO 18265:2013 without any modification.
INTERNATIONAL ISO
STANDARD 18265
Second edition
2013-10-01
Metallic materials — Conversion of
hardness values
Matériaux métalliques — Conversion des valeurs de dureté
Reference number
ISO 18265:2013(E)
©
ISO 2013
ISO 18265:2013(E)
© ISO 2013
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
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Published in Switzerland
ii © ISO 2013 – All rights reserved

ISO 18265:2013(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Principles of conversion . 1
3 Application of conversion tables . 4
3.1 General . 4
3.2 Converting values . 7
3.3 Designation of conversion results . 9
3.4 Notes on use of conversion tables .10
Annex A (informative) Conversion table for unalloyed, low alloy steels and cast steel .12
Annex B (informative) Conversion tables for steels for quenching and tempering .17
Annex C (informative) Conversion tables for steels for cold working .37
Annex D (informative) Conversion tables for high speed steels .48
Annex E (informative) Conversion tables for hardmetals .61
Annex F (informative) Conversion tables for non-ferrous metals and alloys .65
Annex G (informative) Conversion tables for tool steels .76
Annex H (informative) Remarks on the effect of the changed test conditions .80
Bibliography .84
ISO 18265:2013(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. 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. 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
The committee responsible for this document is ISO/TC 164, Mechanical testing of metals, Subcommittee
SC 3, Hardness testing.
This second edition cancels and replaces the first edition (ISO 18265:2003) which has been
technically revised.
iv © ISO 2013 – All rights reserved

ISO 18265:2013(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 this table 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
[1]
Physikalisch-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 6892-1, and the calibration procedures conform with those specified in ISO 7500-1
and ISO 9513.
Annex G contains the results on the conversion of hardness values of two tool steels with the assistance
of the Verein Deutscher Eisenhüttenleute (VDEh) which were obtained in the year 2007.
Users of this International Standard should take note of Clause 2, especially the concluding warning.
INTERNATIONAL STANDARD ISO 18265:2013(E)
Metallic materials — Conversion of hardness values
1 Scope
This International Standard specifies the principles of the conversion of hardness values to equivalent
values in other hardness scales and to estimates of tensile strength. It gives general information on the
use of the conversion tables.
The conversion tables in Annexes A to G apply to
— unalloyed and low alloy steels and cast steel,
— steels for quenching and tempering,
— steels for cold working,
— high speed steels,
— tool steels,
— hardmetals, and
— non-ferrous metals and alloys.
NOTE 1 The conversion tables in Annexes B to G 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.
NOTE 2 Annex H gives information about the effects of changes of the test procedure in the standards specifying
the hardness tests.
Converted values obtained using this International Standard are only directly applicable to the exact
material tested. For all other materials, they provide an indicator only. In all cases, the converted values
are not intended as replacements for values obtained by the correct standard method. In particular,
tensile strength estimates are the least reliable converted values in this International Standard.
Sections of this International Standard are reprinted, with permission of ASTM International, from
ASTM E140 Standard Hardness Conversion Tables for Metals Relationship among Brinell Hardness, Vickers
Hardness, Rockwell Hardness, Superficial Harness, Knoop Hardness, and Scleroscope Hardness.
2 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.
ISO 18265:2013(E)
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.
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 drawn for hardness-to-hardness conversions. This may be done as long as the following
conditions are fulfilled.
— The hardness test method used is only employed internally, and the results obtained will 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 shall have been derived from a sufficiently large number of parallel
experiments using both scales and carried out on the material in question.
— Converted results are to be expressed in such a manner that it is clear which method was used to
determine the original hardness value.
However, the conversion values in this International Standard are informative only. A measurement
made according to the correct hardness (or tensile) standard for the scale being reported shall always
take precedence over a hardness (or strength) value derived from a conversion table within this
International Standard. Similarly, a value derived by conversion shall not provide sufficient grounds
either for a complaint or for proof of meeting an acceptance criterion.
WARNING — In practice, an attempt is often made to establish a strong relationship between the
original and converted values without taking the characteristics of the material under test into
consideration. 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 References [2] and [3]).
2 © ISO 2013 – All rights reserved

ISO 18265:2013(E)
Key
X Hardness HV 30
Y Tensile strength, R in MPa
m
1 untreated, soft annealed, normalized
2 quenched and tempered
Figure 1 — HV 30/R curves for quenching and tempering steels in various heat treatment
m
conditions
ISO 18265:2013(E)
Key
X Hardness HV30 3 R /R =0,70 to 0,79 normal annealed
e m
Y Tensile strength, R in MPa 4 R /R =0,70 to 0,79 heat treated
m e m
1 R /R =0,45 to 0,59 5 R /R =0,80 to 0,89
e m e m
2 R /R =0,60 to 0,69 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
3 Application of conversion tables
3.1 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 elastic
and plastic deformation. For this reason, the given conversion relationship provides greater equivalency
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 equivalency 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.
4 © ISO 2013 – All rights reserved

ISO 18265:2013(E)
Measurement best practice shall be defined by the hardness test adopted.
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. Different geometry indentations
are affected differently by these effects and so conversions from one hardness scale to another may no
longer be consistent even in the same sample.
Hardness values shall only be converted when the prescribed test method cannot be used, for example
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.
Converted values shall not be used as the basis for proof of compliance (or not) to a specification or
contract (any necessary exceptions therefore require specific agreement between the parties concerned).
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 (ISO 6506-1, ISO 6507-1, ISO 6508-1) used.
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 sufficiently smooth;
depending on the hardness test method and the test force a suitable method of surface preparation has to
be selected, e.g. machine-finishing (for macro hardness) up to polishing (for low-force and micro hardness).
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. 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, in which case the converted values are to be established on the basis
of the mean of five individual values.
ISO 18265:2013(E)
Key
X Vickers hardness HV30 1 non-ferrous metal
Y Rockwell hardness 2 steel
Y Brinell hardness 3 hardmetal
a
Brinell hardness, determined with steel ball (HBS)
b
Brinell hardness, determined with hardmetal ball
(HBW)
This figure is intended only as an aid in selecting an alternative test method and is not to be used for conversion
purposes.
NOTE The designation “HB5D ” corresponds to the force-diameter ratio according to ISO 6506-1.
Figure 3 — Various hardness scales compared to the Vickers scale
6 © ISO 2013 – All rights reserved

ISO 18265:2013(E)
Key
X Brinell hardness HB/ Vickers hardness HV 1 HB10/1 000
X Rockwell hardness, HR according to its different 2 HB10/500 and HB 5/250
scales
Y Indentation, depth, µm 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
3.2 Converting values
3.2.1 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 A to G. Essential criteria
m
which should be taken into account when selecting a hardness test method are discussed in this clause.
ISO 18265:2013(E)
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
Converted values from table: 270 HV ≙ 26,9 HRC
300 HV ≙ 31,0 HRC
330 HV ≙ 34,6 HRC
+36,
The converted value, 31 HRC, for the nominal value 300 HV no longer represents the mean of the upper
−41,
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.
Key
X HV 30
Y HRC
Figure 5 — Shift of the nominal value when converting hardness values
3.2.2 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
K K
arithmetic mean of five individual values.) The curves have been arranged so that interpolation between
neighboring curves is possible. The reproducibility, R, is to be calculated on the basis of five measurements
as shown in 3.4.2 for various hardness test methods.
The uncertainty curves only take account of the effects of the random errors of the measured value on
the converted value. However, they do not take account of 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 3.4. For this reason, hardness
testing machines are to 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
8 © ISO 2013 – All rights reserved

ISO 18265:2013(E)
hardness testing. Figure 6 illustrates the determination of the uncertainty, u, of a converted hardness
value (dashed line) according to the example below.
EXAMPLE
— 500 HV
Measured, corrected mean hardness H
K
— Converted value as in Annex C 49,5 HRC
— Calculated reproducibility limit, R 2,0 %
— Uncertainty of converted value, u ± 0,7 HRC

Key
X
H in HV 30
K
Y u in HRC
Figure 6 — Determining uncertainty of a converted hardness value (example)
3.3 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
ISO 18265:2013(E)
EXAMPLE 2 If it is agreed that the uncertainty of the converted value is to be given, this is included in the
result as follows:
EXAMPLE 3 Conversions into tensile strength values are expressed as follows:
3.4 Notes on use of conversion tables
3.4.1 Selection of alternative hardness test methods
3.4.1.1 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 (y-axes), 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.
3.4.1.2 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.
3.4.1.3 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.
3.4.2 Calculating the reproducibility limit, R
The reproducibility limit, R, expressed as a percentage, is to be calculated for the different hardness test
methods as shown in Equations (1) to (3).
10 © ISO 2013 – All rights reserved

ISO 18265:2013(E)
For HRB and HRF testing:
HH−
maxmin
R= x100 (1)
130−H
For HRC, HRA, HRD, HRN and HRT testing:
HH−
maxmin
R= x100 (2)
100−H
where
H H are the highest and lowest measured hardness values;
max, min
is the mean of measured hardness values.
H
For HV, Vickers microhardness, and HB testing:
dd−
maxmin
R= x100 (3)
d
where
d , d are the largest and smallest measured indentation diagonals (Vickers) or the largest
max min
and smallest diameters (Brinell);
is the mean of measured diagonals or diameters.
d
3.4.3 Effect of the systematic error
The effect of systematic errors of hardness values on conversion results is illustrated in the following
example.
EXAMPLE According to Table E.2, a hardness value of 87,8 HRA corresponds to a converted value of
1 180 HV 50. In this hardness range, the limits of error of the testing machines (see ISO 6508-2 and ISO 6507-2)
are ±1,5 HRA and ±23,6 HV 50, respectively (i.e. ±2 % of the hardness value). A systematic error of a Rockwell
testing machine of +1,4 HRA lies within the permissible limits of error, although this still would lead to a deviation
of 130 HV 50 for the converted value if no correction is made before conversion. Deviations of this magnitude
occur particularly when converting from Rockwell to Vickers or Brinell values.
ISO 18265:2013(E)
Annex A
(informative)
Conversion table for unalloyed, low alloy steels and cast steel
WARNING — Hardness conversions are no substitute for direct measurements. These tables should
be used with caution and only in accordance with the principles of conversions, see Clause 2.
The values in this table are considered to be estimates for indication only. The hardness values lie outside
the defined conditions of the relevant hardness test standard. The tensile strength values were not
obtained under reproducible conditions and it is now impossible to determine the uncertainty of the data.
A.1 Hardness-to-hardness conversion
When considering the confidence level of converted hardness values, the uncertainty of the hardness
test method as well as the width of the conversion scatterband must be taken into account, as shown in
Figure A.1. Curve a characterizes the mean conversion relationship upon which the values given in this
Annex are based. Curves b and b delineate the areas on either side of a which take into consideration
1 2
the different elasticities of the steels tested. In an ideal conversion, the hardness value x becomes y .
0 0
Taking account of the scatterband between b and b , practically every hardness value between y and
1 2 01
y is obtainable. It should be borne in mind that, because the hardness value x is associated with the
02 0
uncertainty of the relevant test method, the actual hardness can fluctuate between x and x and thus
1 2
the converted value will lie between y and y .
11 22
NOTE In the interlaboratory tests carried out by the VDEh (see the Introduction), the evaluation of about
700 results for the conversion between HV10 values and HB values produced (graphically depicted) scatterband
widths of ±24 HV10 and ±23 HB, respectively. Regression analysis was not performed.
A.2 Hardness-to-tensile-strength conversion
While hardness-to-hardness conversion involves considerable scatter and systematic errors, conversion
of hardness to tensile strength values produces even greater scattering. One reason for this is that a
great uncertainty can be affected by microstructural changes (e.g. resulting from heat treatment or cold
working) within even the same type of steel.
The tensile strength values given in Table A.1 are therefore only approximate values which cannot take
the place of the results of tensile testing.
NOTE 1 In the interlaboratory tests carried out by the VDEh (see Introduction), the evaluation of about
700 results for the conversion from HV10 values to tensile strength values produced (graphically depicted)
scatterband widths of ± 25 HV10 and ± 85 N/mm , respectively. It was also shown that systematic deviations
from the mean were possible for particular steel groups. For instance, for pearlitic steels within the hardness
range of 300 HV10 to 500 HV10, it was found that the converted tensile values were, on the average, about 100
MPa higher than those listed in Table A.1. Regression analysis was not performed.
NOTE 2 Since high-strength structural steels are now being tested at an increasing rate, the tensile strengths
in Table A.1 were extended up to 2 180 MPa. The tensile strength values in this table are based on results of
extensive interlaboratory tests by the VDEh in the hardness range up to about 420 HV10, and on the results from
Reference [4] which are gradually approached by the values in the range above 420 HV10.
12 © ISO 2013 – All rights reserved

ISO 18265:2013(E)
Table A.1 — Conversion of hardness-to-hardness or hardness-to-tensile-strength values for
unalloyed and low alloy steels and cast steel
Tensile Vickers Brinell Rockwell hardness
strength hardness hardness
a
MPa HV10 HB HRB HRF HRC HRA HRD HR15N HR30N HR45N
255 80 76,0
270 85 80,7 41,0
285 90 85,5 48,0 82,6
305 95 90,2 52,0
320 100 95,0 56,2 87,0
335 105 99,8
350 110 105 62,3 90,5
370 115 109
385 120 114 66,7 93,6
400 125 119
415 130 124 71,2 96,4
430 135 128
450 140 133 75,0 99,0
465 145 138
480 150 143 78,7 101,4
495 155 147
510 160 152 81,7 103,6
530 165 156
545 170 162 85,0 105,5
560 175 166
575 180 171 87,1 107,2
595 185 176
610 190 181 89,5 108,7
625 195 185
640 200 190 91,5 110,1
660 205 195 92,5
675 210 199 93,5 111,3
690 215 204 94,0
705 220 209 95,0 112,4
720 225 214 96,0
a
Brinell hardness values up to 450 HB were determined using a steel ball indenter, those above this value were determined
with a hardmetal ball.
NOTE 1  Values in parentheses are those lying outside the defined range of the standard test method but which may used
as estimates.
NOTE 2  The value of the tension test are not based on method A (10.3 Testing rate based on close-loop control at the rate
of the extension) in ISO 6892-1:2009
ISO 18265:2013(E)
Table A.1 (continued)
Tensile Vickers Brinell Rockwell hardness
strength hardness hardness
a
MPa HV10 HB HRB HRF HRC HRA HRD HR15N HR30N HR45N
740 230 219 96,7 113,4
755 235 223
770 240 228 98,1 114,3 20,3 60,7 40,3 69,6 41,7 19,9
785 245 233 21,3 61,2 41,1 70,1 42,5 21,1
800 250 238 99,5 115,1 22,2 61,6 41,7 70,6 43,4 22,2
820 255 242 23,1 62,0 42,2 71,1 44,2 23,2
835 260 247 (101) 24,0 62,4 43,1 71,6 45,0 24,3
850 265 252 24,8 62,7 43,7 72,1 45,7 25,2
865 270 257 (102) 25,6 63,1 44,3 72,6 46,4 26,2
880 275 261 26,4 63,5 44,9 73,0 47,2 27,1
900 280 266 (104) 27,1 63,8 45,3 73,4 47,8 27,9
915 285 271 27,8 64,2 46,0 73,8 48,4 28,7
930 290 276 (105) 28,5 64,5 46,5 74,2 49,0 29,5
950 295 280 29,2 64,8 47,1 74,6 49,7 30,4
965 300 285 29,8 65,2 47,5 74,9 50,2 31,1
995 310 295 31,0 65,8 48,4 75,6 51,3 32,5
1 030 320 304 32,2 66,4 49,4 76,2 52,3 33,9
1 060 330 314 33,3 67,0 50,2 76,8 53,6 35,2
1 095 340 323 34,4 67,6 51,1 77,4 54,4 36,5
1 125 350 333 35,5 68,1 51,9 78,0 55,4 37,8
1 155 360 342 36,6 68,7 52,8 78,6 56,4 39,1
1 190 370 352 37,7 69,2 53,6 79,2 57,4 40,4
1 220 380 361 38,8 69,8 54,4 79,8 58,4 41,7
1 255 390 371 39,8 70,3 55,3 80,3 59,3 42,9
1 290 400 380 40,8 70,8 56,0 80,8 60,2 44,1
1 320 410 390 41,8 71,4 56,8 81,4 61,1 45,3
1 350 420 399 42,7 71,8 57,5 81,8 61,9 46,4
1 385 430 409 43,6 72,3 58,2 82,3 62,7 47,4
1 420 440 418 44,5 72,8 58,8 82,8 63,5 48,4
1 455 450 428 45,3 73,3 59,4 83,2 64,3 49,4
a
Brinell hardness values up to 450 HB were determined using a steel ball indenter, those above this value were determined
with a hardmetal ball.
NOTE 1  Values in parentheses are those lying outside the defined range of the standard test method but which may used
as estimates.
NOTE 2  The value of the tension test are not based on method A (10.3 Testing rate based on close-loop control at the rate
of the extension) in ISO 6892-1:2009
14 © ISO 2013 – All rights reserved

ISO 18265:2013(E)
Table A.1 (continued)
Tensile Vickers Brinell Rockwell hardness
strength hardness hardness
a
MPa HV10 HB HRB HRF HRC HRA HRD HR15N HR30N HR45N
1 485 460 437 46,1 73,6 60,1 83,6 64,9 50,4
1 520 470 447 46,9 74,1 60,7 83,9 65,7 51,3
1 555 480 456 47,7 74,5 61,3 84,3 66,4 52,2
1 595 490 466 48,4 74,9 61,6 84,7 67,1 53,1
1 630 500 475 49,1 75,3 62,2 85,0 67,7 53,9
1 665 510 485 49,8 75,7 62,9 85,4 68,3 54,7
1 700 520 494 50,5 76,1 63,5 85,7 69,0 55,6
1 740 530 504 51,1 76,4 63,9 86,0 69,5 56,2
1 775 540 513 51,7 76,7 64,4 86,3 70,0 57,0
1 810 550 523 52,3 77,0 64,8 86,6 70,5 57,8
1 845 560 532 53,0 77,4 65,4 86,9 71,2 58,6
1 880 570 542 53,6 77,8 65,8 87,2 71,7 59,3
1 920 580 551 54,1 78,0 66,2 87,5 72,1 59,9
1 955 590 561 54,7 78,4 66,7 87,8 72,7 60,5
1 995 600 570 55,2 78,6 67,0 88,0 73,2 61,2
2 030 610 580 55,7 78,9 67,5 88,2 73,7 61,7
2 070 620 589 56,3 79,2 67,9 88,5 74,2 62,4
2 105 630 599 56,8 79,5 68,3 88,8 74,6 63,0
2 145 640 608 57,3 79,8 68,7 89,0 75,1 63,5
2 180 650 618 57,8 80,0 69,0 89,2 75,5 64,1
660 58,3 80,3 69,4 89,5 75,9 64,7
670 58,8 80,6 69,8 89,7 76,4 65,3
680 59,2 80,8 70,1 89,8 76,8 65,7
690 59,7 81,1 70,5 90,1 77,2 66,2
700 60,1 81,3 70,8 90,3 77,6 66,7
720 61,0 81,8 71,5 90,7 78,4 67,7
740 61,8 82,2 72,1 91,0 79,1 68,6
760 62,5 82,6 72,6 91,2 79,7 69,4
780 63,3 83,0 73,3 91,5 80,4 70,2
800 64,0 83,4 73,8 91,8 81,1 71,0
a
Brinell hardness values up to 450 HB were determined using a steel ball indenter, those above this value were determined
with a hardmetal ball.
NOTE 1  Values in parentheses are those lying outside the defined range of the standard test method but which may used
as estimates.
NOTE 2  The value of the tension test are not based on method A (10.3 Testing rate based on close-loop control at the rate
of the extension) in ISO 6892-1:2009
ISO 18265:2013(E)
Table A.1 (continued)
Tensile Vickers Brinell Rockwell hardness
strength hardness hardness
a
MPa HV10 HB HRB HRF HRC HRA HRD HR15N HR30N HR45N
820 64,7 83,8 74,3 92,1 81,7 71,8
840 65,3 84,1 74,8 92,3 82,2 72,2
860 65,9 84,4 75,3 92,5 82,7 73,1
880 66,4 84,7 75,7 92,7 83,1 73,6
900 67,0 85,0 76,1 92,9 83,6 74,2
920 67,5 85,3 76,5 93,0 84,0 74,8
940 68,0 85,6 76,9 93,2 84,4 75,4
a
Brinell hardness values up to 450 HB were determined using a steel ball indenter, those above this value were determined
with a hardmetal ball.
NOTE 1  Values in parentheses are those lying outside the defined range of the standard test method but which may used
as estimates.
NOTE 2  The value of the tension test are not based on method A (10.3 Testing rate based on close-loop control at the rate
of the extension) in ISO 6892-1:2009
Key
X determined hardness value
Y converted value
CAUTION — There may be very large scatter bands in the conversions of different kinds of cast steel.
Figure A.1 — Scatter band for hardness-to-hardness conversion (schematic)
16 © ISO 2013 – All rights reserved

ISO 18265:2013(E)
Annex B
(informative)
Conversion tables for steels for quenching and tempering
WARNING — Hardness conversions are no substitute for direct measurements. These tables should
be used with caution and only in accordance with the principles of conversions, see Clause 2.
The values and curves presented in this Annex are based on a report of the Physikalisch-Technische
[1]
Bundesanstalt (PTB), the German national institute for science and technology, and are reproduced
with their permission (see also the Introduction for further information).
The values in these conversion tables are based on the results of testing carried out on steels as in
TGL 6547 that have been quenched and tempered. The steel grades that were tested are listed in
Table B.1, which also provides an overview of the former designations used in the TGL standard along
with the corresponding designations as in EN 10083-1. Tables B.2 to B.4 give conversion values for the
steels in various heat treatment conditions, while Tables B.5 to B.7 give an overview of the uncertainty
curves presented in Figures B.1 to B.68 which are to be used in conjunction with the conversion tables.
NOTE A useful reference book is [24]. It provides information for the comparison of different national and
international steel designations with regard to their compositions.
ISO 18265:2013(E)
Table B.1 — Quenching and tempering steels tested
Steel grade Steel grade
(as in TGL 6547) (as in EN 10083-1)
Material no. Name
C25 1.1158 C25E
C35 1.1180 C35R
CK45 1.1191 C45E
a
CK55 1.1203 C55E
C60 1.1223 C60R
b c c
CK67
a c c
24CrMoV5.5
d
30CrMoV9 1.7707 30CrMoV9
d
30Mn5 1.1165 30Mn5
34Cr4 1.7033 34Cr4
d
37MnSi5 1.5122 37MnSi5
38CrSi6 1.7038 37CrS4
40Cr4 1.7035 41Cr4
42CrMo4 1.7225 42CrMo4
d
42MnV7 1.5223 42MnV7
50CrV4 1.8159 51CrV4
d
50MnSi4 1.5131 50MnSi4
a
60CrMo4 1.7228 50CrMo4
a
Not included in TGL 6547.
b
As in TGL 7975.
c
Not included in EN 10083-1 and in DIN 17200.
d
According to DIN 17200:1987-03 (withdrawn, replaced by EN 10083-1) but not included in EN 10083-1.
18 © ISO 2013 – All rights reserved

ISO 18265:2013(E)
Table B.2 — Conversion of hardness-to-hardness and hardness-to-tensile-strength values for
quenching and tempering steels in the quenched tempered conditions
HV HBW HRC HRA HR45N HR30N HR15N HRB HRF HR45T HR30T HR15T R
m
210 205 15,3 57,2 13,4 36,1 65,2 94,8 110,4 65,4 76,8 89,2 651
220 215 17,4 58,4 15,9 38,1 66,5 96,7 111,4 67,6 78,5 90,0 683
230 225 19,3 59,6 18,2 40,4 67,8 98,4 112,4 69,6 80,0 90,8 716
240 235 21,2 60,6 20,4 41,8 68
...