SIST EN ISO 6508-1:2015
(Main)Metallic materials - Rockwell hardness test - Part 1: Test method (ISO 6508-1:2015)
Metallic materials - Rockwell hardness test - Part 1: Test method (ISO 6508-1:2015)
This part of ISO 6508 specifies the method for Rockwell regular and Rockwell superficial hardness tests
(scales and applicable range of application according to Table 1) for metallic materials and is applicable
to stationary and portable hardness testing machines.
For specific materials and/or products, other specific International Standards apply (for instance,
ISO 3738-1 and ISO 4498).
NOTE Attention is drawn to the fact that the use of tungsten carbide composite for ball indenters is considered
to be the standard type of Rockwell indenter ball. Steel indenter balls are allowed to continue to be used only
when complying with Annex A.
Metallische Werkstoffe - Härteprüfung nach Rockwell - Teil 1: Prüfverfahren (ISO 6508-1:2015)
Matériaux métalliques - Essai de dureté Rockwell - Partie 1: Méthode d'essai (ISO 6508-1:2015)
L'ISO 6508-1:2015 spécifie la méthode d'essai de dureté Rockwell normale et de dureté superficielle Rockwell (échelles et domaine d'application applicable conformément au Tableau 1) pour les matériaux métalliques. Elle s'applique aux machines d'essai de dureté fixes et portables.
Pour des matériaux et/ou produits spécifiques, d'autres Normes internationales spécifiques s'appliquent (par exemple ISO 3738‑1 et ISO 4498).
NOTE L'attention est attirée sur le fait que l'utilisation de composite de carbure de tungstène pour les pénétrateurs à billes est considérée être le type courant de bille de pénétrateur Rockwell. Des billes de pénétrateur en acier peuvent continuer d'être utilisées seulement en conformité avec l'Annexe A.
Kovinski materiali - Preskus trdote po Rockwellu - 1. del: Preskusna metoda (ISO 6508-1:2015)
Ta del standarda ISO 6508 določa metodo običajnega preskusa trdote po Rockwellu in preskusa trdote z majhnimi obremenitvami po Rockwellu (merila in ustrezen obseg uporabe v skladu s preglednico 1) za kovinske materiale ter se uporablja za nepremične in premične naprave za preskušanje trdote.
Za določene materiale in/ali izdelke se uporabljajo drugi ustrezni mednarodni standardi (na primer
standarda ISO 3738-1 in ISO 4498).
OPOMBA: Opozoriti je treba, da se za standardno vrsto vtisne krogle po Rockwellu šteje kroglično vtisno telo iz kompozita volframovega karbida. Uporaba jeklenih vtisnih krogel je še naprej dovoljena pod pogojem, da so skladne z dodatkom A.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 6508-1:2015
01-maj-2015
1DGRPHãþD
SIST EN ISO 6508-1:2006
Kovinski materiali - Preskus trdote po Rockwellu - 1. del: Preskusna metoda (ISO
6508-1:2015)
Metallic materials - Rockwell hardness test - Part 1: Test method (ISO 6508-1:2015)
Metallische Werkstoffe - Härteprüfung nach Rockwell - Teil 1: Prüfverfahren (ISO 6508-
1:2015)
Matériaux métalliques - Essai de dureté Rockwell - Partie 1: Méthode d'essai (ISO 6508-
1:2015)
Ta slovenski standard je istoveten z: EN ISO 6508-1:2015
ICS:
77.040.10 Mehansko preskušanje kovin Mechanical testing of metals
SIST EN ISO 6508-1:2015 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 6508-1:2015
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SIST EN ISO 6508-1:2015
EUROPEAN STANDARD
EN ISO 6508-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2015
ICS 77.040.10 Supersedes EN ISO 6508-1:2005
English Version
Metallic materials - Rockwell hardness test - Part 1: Test method
(ISO 6508-1:2015)
Matériaux métalliques - Essai de dureté Rockwell - Partie 1: Metallische Werkstoffe - Härteprüfung nach Rockwell - Teil
Méthode d'essai (ISO 6508-1:2015) 1: Prüfverfahren (ISO 6508-1:2015)
This European Standard was approved by CEN on 12 December 2014.
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, 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: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6508-1:2015 E
worldwide for CEN national Members.
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SIST EN ISO 6508-1:2015
EN ISO 6508-1:2015 (E)
Contents
Page
Foreword .3
2
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SIST EN ISO 6508-1:2015
EN ISO 6508-1:2015 (E)
Foreword
This document (EN ISO 6508-1:2015) 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 2015, and conflicting national standards shall be
withdrawn at the latest by September 2015.
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 6508-1:2005.
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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 6508-1:2015 has been approved by CEN as EN ISO 6508-1:2015 without any modification.
3
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SIST EN ISO 6508-1:2015
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SIST EN ISO 6508-1:2015
INTERNATIONAL ISO
STANDARD 6508-1
Third edition
2015-03-01
Metallic materials — Rockwell
hardness test —
Part 1:
Test method
Matériaux métalliques — Essai de dureté Rockwell —
Partie 1: Méthode d’essai
Reference number
ISO 6508-1:2015(E)
©
ISO 2015
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SIST EN ISO 6508-1:2015
ISO 6508-1:2015(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2015
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
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Tel. + 41 22 749 01 11
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E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2015 – All rights reserved
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SIST EN ISO 6508-1:2015
ISO 6508-1:2015(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Principle . 1
4 Symbols, abbreviated terms and designations . 1
5 Testing machine . 4
6 Test piece . 5
7 Procedure. 5
8 Uncertainty of the results . 7
9 Test report . 7
10 Conversions to other hardness scales or tensile strength values .7
Annex A (normative) Special HR30TSm and HR15TSm test for thin products .8
Annex B (normative) Minimum thickness of the test piece in relation to the Rockwell hardness .9
Annex C (normative) Corrections to be added to Rockwell hardness values obtained on
convex cylindrical surfaces .12
Annex D (normative) Corrections to be added to Rockwell hardness C scale values obtained
on spherical test surfaces of various diameters .15
Annex E (normative) Daily Verification Procedure .16
Annex F (normative) Inspection of diamond indenters .19
Annex G (informative) Uncertainty of the measured hardness values .20
Annex H (informative) CCM - Working Group on Hardness .29
Annex I (informative) Rockwell Hardness Measurement Traceability .30
Bibliography .33
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SIST EN ISO 6508-1:2015
ISO 6508-1:2015(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 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 third edition cancels and replaces the second edition (ISO 6508-1:2005), which has been
technically revised.
ISO 6508 consists of the following parts, under the general title Metallic materials — Rockwell hardness test:
— Part 1: Test method
— Part 2: Verification and calibration of testing machines and indenters
— Part 3: Calibration of reference blocks
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SIST EN ISO 6508-1:2015
INTERNATIONAL STANDARD ISO 6508-1:2015(E)
Metallic materials — Rockwell hardness test —
Part 1:
Test method
1 Scope
This part of ISO 6508 specifies the method for Rockwell regular and Rockwell superficial hardness tests
(scales and applicable range of application according to Table 1) for metallic materials and is applicable
to stationary and portable hardness testing machines.
For specific materials and/or products, other specific International Standards apply (for instance,
ISO 3738-1 and ISO 4498).
NOTE Attention is drawn to the fact that the use of tungsten carbide composite for ball indenters is considered
to be the standard type of Rockwell indenter ball. Steel indenter balls are allowed to continue to be used only
when complying with Annex A.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 6508-2:2015, Metallic materials — Rockwell hardness test — Part 2: Verification and calibration of
testing machines
ISO 6508-3:2015, Metallic materials — Rockwell hardness test — Part 3: Calibration of reference blocks
3 Principle
An indenter of specified size, shape, and material is forced into the surface of a test specimen under two
force levels using the specific conditions defined in Clause 7. The specified preliminary force is applied
and the initial indentation depth is measured, followed by the application and removal of a specified
additional force, returning to the preliminary force. The final indentation depth is then measured and
the Rockwell hardness value is derived from the difference, h, in the final and initial indentation depths
and the two constants N and S (see Figure 1, Table 1 and Table 2) as:
h
Rockwell hardness=−N (1)
S
4 Symbols, abbreviated terms and designations
4.1 See Table 1, Table 2, Table 3, and Figure 1.
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SIST EN ISO 6508-1:2015
ISO 6508-1:2015(E)
Table 1 — Rockwell Regular scales
Rockwell Hardness Type of indenter Preliminary Total Scaling Full Applicable
symbol force force Constant Range range of applica-
Regular
tion (Rockwell
hardness Unit Constant
Regular
cale
F F S N
0
hardness scales)
A HRA Diamond cone 98,07 N 588,4 N 0,002 mm 100 20 to 95 HRA
B HRBW Ball 1,587 5 mm 98,07 N 980,7 N 0,002 mm 130 10 to 100 HRBW
a
C HRC Diamond cone 98,07 N 1,471 kN 0,002 mm 100 20 to 70 HRC
D HRD Diamond cone 98,07 N 980,7 N 0,002 mm 100 40 to 77 HRD
E HREW Ball 3,175 mm 98,07 N 980,7 N 0,002 mm 130 70 to 100 HREW
F HRFW Ball 1,587 5 mm 98,07 N 588,4 N 0,002 mm 130 60 to 100 HRFW
G HRGW Ball 1,587 5 mm 98,07 N 1,471 kN 0,002 mm 130 30 to 94 HRGW
H HRHW Ball 3,175 mm 98,07 N 588,4 N 0,002 mm 130 80 to 100 HRHW
K HRKW Ball 3,175 mm 98,07 N 1,471 kN 0,002 mm 130 40 to 100 HRKW
a
The applicable range of application can be extended to 10 HRC if the surfaces of the diamond cone and spherical tip are
polished for a penetration depth of at least 0,4 mm.
Table 2 — Rockwell Superficial scales
Rockwell Hardness Type of Preliminary Total Scaling Full Applicable
Superficial symbol indenter force force Constant Range range of appli-
hardness Constant cation (Rock-
Unit
scale well Superficial
N
hardness scales)
F F S
0
15N HR15N Diamond cone 29,42 N 147,1 N 0,001 mm 100 70 to 94 HR15N
30N HR30N Diamond cone 29,42 N 294,2 N 0,001 mm 100 42 to 86 HR30N
45N HR45N Diamond cone 29,42 N 441,3 N 0,001 mm 100 20 to 77 HR45N
15T HR15TW Ball 1,587 5 mm 29,42 N 147,1 N 0,001 mm 100 67 to 93 HR15TW
30T HR30TW Ball 1,587 5 mm 29,42 N 294,2 N 0,001 mm 100 29 to 82 HR30TW
45T HR45TW Ball 1,587 5 mm 29,42 N 441,3 N 0,001 mm 100 10 to 72 HR45TW
Scales using indenter balls with diameter 6,350 mm and 12,70 mm may also be used, if specified in the
product specification or by special agreement. See ASTM E 18 for additional scales using these ball sizes.
NOTE 1 For certain materials, the applicable range of application might be narrower than those indicated.
NOTE 2 The numbers representing the test forces were originally based on units of kgf. For example, the total
test force of 30 kgf has been converted to 294,2 N.
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SIST EN ISO 6508-1:2015
ISO 6508-1:2015(E)
Table 3 — Symbols and abbreviated terms
Symbol/
Abbreviated Definition Unit
term
F Preliminary test force N
0
F Additional test force (total force minus preliminary force) N
1
F Total test force N
S Scaling constant, specific to the scale mm
N Full range constant, specific to the scale -
h Permanent depth of indentation under preliminary test force after removal of
mm
additional test force (permanent indentation depth)
HRA
h
Rockwell Regular hardness =100−
HRC
0,002
HRD
HRBW
HREW
HRFW h
Rockwell Regular hardness =130−
0,002
HRGW
HRHW
HRKW
HRN
h
Rockwell Superficial hardness =100−
HRTW
0,001
4.2 The following is an example of the designation of Rockwell hardness.
EXAMPLE
70 HR 30 T W
indication of type of ball used, W = Tungsten carbide
composite
Rockwell scale symbol (see Tables 1 or 2)
Rockwell hardness symbol
NOTE 1 Previous versions of this part of ISO 6508 allowed the use of steel indenter balls, which required
the suffix S.
NOTE 2 For the HR30TSm and HR15TSm scales defined in Annex A, a capital S and a lower-case m is used
indicating the use of steel indenter balls and a diamond spot specimen holder.
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SIST EN ISO 6508-1:2015
ISO 6508-1:2015(E)
Y
F F +F F
0 0 1 0
5
6
1
7
4
2
8
3
7
7
Key
X time 4 permanent indentation depth, h
Y indenter position 5 surface of specimen
1 indentation depth by preliminary force, F 6 reference plane for measurement
0
2 indentation depth by additional test force, F 7 position of indenter
1
3 elastic recovery just after removal of additional test force, 8 indentation depth vs. time curve
F
1
Figure 1 — Rockwell principle diagram
5 Testing machine
5.1 Testing machine, shall be capable of applying the test forces for some or all of the Rockwell
hardness scales as shown in Table 1 and Table 2, performing the procedure defined in Clause 7, and
complying with all of the requirements defined in ISO 6508-2:2015.
5.2 Spheroconical diamond indenter, shall be in accordance with ISO 6508-2:2015, with an
included angle of 120° and radius of curvature at the tip of 0,2 mm. Diamond indenters shall be certified
for use for either
— only the regular Rockwell diamond scales,
— only the superficial Rockwell diamond scales, or
— both the regular and the superficial Rockwell diamond scales.
5.3 Ball indenter, shall be tungsten carbide composite in accordance with ISO 6508-2:2015, with a
diameter of 1,587 5 mm or 3,175 mm (see Note 1 and Note 2)
NOTE 1 Ball indenters normally consist of a spherical ball and a separate appropriately designed holder. Single-
piece spherically tipped indenters are allowed, provided that the surface of the indenter that makes contact with
the test piece meets the size, shape, finish, and hardness requirements defined in ISO 6508-2:2015, 6.3.1, and
meets the performance requirements of ISO 6508-2:2015, 6.3.2.
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SIST EN ISO 6508-1:2015
ISO 6508-1:2015(E)
NOTE 2 Attention is drawn to the fact that the use of tungsten carbide composite for ball indenters is the
standard type of Rockwell indenter ball. Steel indenter balls can only be used when performing Rockwell
HR30TSm and HR15TSm tests according to Annex A.
6 Test piece
6.1 The test shall be carried out on a surface which is smooth and even, free from oxide scale, foreign
matter and, in particular, completely free from lubricants, unless specified otherwise in product or
materials standards. An exception is made for reactive metals, such as titanium, which might adhere to
the indenter. In such situations, a suitable lubricant such as kerosene may be used. The use of a lubricant
shall be reported on the test report.
6.2 Preparation shall be carried out in such a way that any alteration of the surface hardness due to
excessive heating or cold-working for example, is minimized. This shall be taken into account, particularly
in the case of low-depth indentations.
6.3 The thickness of the test piece, or of the layer under test (minimum values are given in Annex B),
shall be at least 10 times the permanent indentation depth for diamond indenters and 15 times the
permanent indentation depth for ball indenters, unless it can be demonstrated that the use of a thinner
test piece does not affect the measured hardness value. In general, no deformation should be visible on
the back of the test piece after the test, although not all such marking is indicative of a bad test.
See Annex A for special requirements for testing very thin sheet metal using the HR30TSm and
HR15TSm scales.
6.4 For tests on convex cylindrical surfaces and spherical surfaces, see 7.11.
7 Procedure
7.1 This part of ISO 6508 has been developed with a laboratory temperature requirement of 10°C to 35°C.
For environments outside the stated requirement, it is the responsibility of the testing laboratory to
assess the impact on testing data produced with testing machines operated in such environments. When
testing is performed outside the recommended temperature limits of 10 °C to 35 °C, the temperature shall
be recorded and reported.
NOTE If significant temperature gradients are present during testing and/or calibration, measurement
uncertainty can increase and out of tolerance conditions can occur.
7.2 The daily verification defined in Annex E shall be performed before the first test of each day for each
scale to be used. The condition of diamond indenters should be checked according to Annex F.
7.3 After each change, or removal and replacement, of the indenter, indenter ball, or test piece support,
perform at least two tests and discard the results, then determine that the indenter and the test piece support
are correctly mounted in the machine by performing the daily verification process defined in Annex E.
7.4 The diamond or ball indenter shall have been the indenter used during the last indirect verification.
If the indenter was not used during the indirect verification and is being used for the first time, it shall be
verified in accordance with the daily verification given in Annex E using at least two test blocks (one from
the low and high ranges as defined in ISO 6508-2:2015, Table 1) for each Rockwell scale that is normally
used. This does not apply to replacing a ball.
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SIST EN ISO 6508-1:2015
ISO 6508-1:2015(E)
7.5 The test piece shall be placed on a rigid support and supported in such a manner that the surface to
be indented is in a plane normal to the axis of the indenter and the line of the indenting force, as well as
to avoid a displacement of the test piece.
Products of cylindrical shape shall be suitably supported, for example, on centering V-block or double
cylinders made of material with a Rockwell hardness of at least 60 HRC. Special attention shall be given
to the correct seating, bearing, and alignment of the indenters, the test piece, the centering V-blocks,
and the specimen holder of the testing machine, since any perpendicular misalignment might result in
incorrect results.
7.6 Bring the indenter into contact with the test surface and apply the preliminary test force, F , without
0
shock, vibration, oscillation, or overload. The preliminary force application time should not exceed 2 s.
+1
The duration of the preliminary test force, F , shall be 3 s.
0
−2
NOTE The requirements for the time durations are given with asymmetric limits.
+1
EXAMPLE 3 s indicates that 3 s is the ideal time duration, with an acceptable range of not less than
−2
1 s (3 s - 2 s) to not more than 4 s (3 s + 1 s).
7.7 Measure the initial indentation depth. For many manual (dial-indicator) machines, this is done by
setting the indicating dial to its set-point or zero position. For many automatic (digital) machines, the
depth measurement is made automatically without the user’s input and might not be displayed.
7.8 Apply the additional force F without shock, vibration, oscillation, or overload to increase the force
1
from F to the total force, F. For the regular Rockwell scale tests, apply the additional test force, F , in not
0 1
less than 1 s and not more than 8 s. For all HRN and HRTW Rockwell superficial test scales, apply the
additional test force, F , in less than or equal to 4 s. It is recommended to perform the same test cycle used
1
during indirect verification.
NOTE There is evidence that some materials might be sensitive to the rate of straining which causes small
changes in the value of the yield stress. The corresponding effect on the termination of the formation of an
indentation can make an alteration in the hardness value.
+1
7.9 The total test force, F, shall be maintained for a duration of 5 s. Remove the additional test force,
−3
+1
F , and, while the preliminary test force, F , is maintained, after 4 s, the final reading shall be made.
1 0
−3
As an exception for test materials exhibiting excessive plastic flow (indentation creep) during the
application of the total test force, special considerations might be necessary since the indenter will
continue to penetrate. When materials require the use of a total force duration that exceeds the 6 s
allowed by the tolerances, the actual extended total force duration used shall be reported following the
test results (for example, 65 HRF/10 s).
7.10 Measure the final indentation depth while the preliminary test force is applied. The Rockwell
hardness number is calculated from the permanent indentation depth, h, using the formula given in
Formula (1) and the information given in Table 1, Table 2, and Table 3. For most Rockwell hardness
machines, the depth measurement is made in a manner that automatically calculates and displays the
Rockwell hardness number.
The derivation of the Rockwell hardness number is illustrated in Figure 1.
7.11 For tests on convex cylindrical surfaces and spherical surfaces, the corrections given in Annex C
(Table C.1, Table C.2, Table C.3 or Table C.4) and in Annex D (Table D.1) shall be applied. The correction
values shall be reported on the test report.
In the absence of corrections for tests on concave surfaces, tests on such surfaces should be the subject
of special agreement.
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SIST EN ISO 6508-1:2015
ISO 6508-1:2015(E)
7.12 Throughout the test, the apparatus shall be protected from shock or vibration.
7.13 The distance between the centres of two adjacent indentations shall be at least three times the
diameter of the indentation. The distance from the centre of any indentation to an edge of the test piece
shall be at least two and a half times the diameter of the indentation.
8 Uncertainty of the results
[3]
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.
[4]
As a reference, an EURAMET Guide CG-16 is available.
— The other possibility is based on indirect calibration using a hardness reference block (abbreviated
[2][3][4][5]
A guideline for the determination is given in Annex G.
as CRM certified reference material).
9 Test report
The laboratory shall record at least the following information and that information shall be included in
the test report, unless agreed by the parties concerned:
a) a reference to this part of ISO 6508 (i.e. ISO 6508-1);
b) all details necessary for the complete identification of the test piece, including the curvature of the
test surface;
c) the test temperature, if it is not within the limits of 10 °C to 35 °C;
d) the hardness result in the format defined in 4.2;
e) all operations not specified in this part of ISO 6508, or regarded as optional;
f) details of any occurrence which might have affected the result;
g) the actual extended total force duration time used, if greater than the 6 s allowed by the tolerances;
h) the date the test was performed;
i) if conversion to another hardness scale is also performed, the basis and method of this conversion
shall be specified (see ISO 18265).
10 Conversions to other hardness scales or tensile strength values
There is no general process for accurately converting Rockwell hardness into other scales, or hardness
into tensile strength. Such conversions, therefore, should be avoided, unless a reliable basis for conversion
can be obtained by comparison tests (see also ISO 18265).
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SIST EN ISO 6508-1
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