ISO/FDIS 14577-3

Date: 2025-07-02
ISO/DISFDIS 14577-3:2025(en)
ISO/TC 164/SC 3/WG 1
Secretariat: DIN BSI
Date: 2026-01-15
Metallic materials — Instrumented indentation test for hardness and
materials parameters —
Part 3:
Calibration of reference blocks
Matériaux métalliques — Essai de pénétration instrumenté pour la détermination de la dureté et de
paramètres des matériaux — Partie 3: Etalonnage des blocs de référence
Partie 3: Étalonnage des blocs de référence
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FDIS stage
ISO/DISFDIS 14577-3:20252026(en)
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iii
Contents Page
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Manufacture of reference blocks. 1
5 Calibrating machine . 2
5.1 General . 2
5.2 Calibration of the test force . 3
5.3 Verification of the indenter . 3
5.4 Calibration of the displacement measuring device . 6
5.5 Testing cycle requirements . 6
6 Calibration procedure . 7
7 Number of indentations . 7
8 Uniformity of the reference blocks . 7
9 Marking . 8
10 Validity . 10
Annex A (informative) Example procedure for measuring elasticity of reference materials with
pulse echo method with traceability. . 12
Bibliography . 15

iv
ISO/DISFDIS 14577-3:20252026(en)
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals,
Subcommittee SC 3, Hardness testing., in collaboration with the European Committee for Standardization
(CEN) Technical Committee CEN/TC 459, Test methods for steel (other than chemical analysis, in accordance
with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 14577--3:2015), which has been technically
revised.
The main changes are as follows:
— — Specification of the shape of the reference block.
— — Modifications in the procedure for the verification of the indenter.
— — Testing cycle requirements.
— — Changing the conditions for the verification of the uniformity of the reference blocks.
— 0— Annex A was added.
A list of all parts in the ISO 14577 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
Introduction
Hardness has typically been defined as the resistance of a material to permanent penetration by another
harder material. The results obtained when performing Rockwell, Vickers, and Brinell tests are determined
after the test force has been removed. Therefore, the effect of elastic deformation under the indenter has been
ignored.
ISO 14577 (all parts) has been prepared to enable the user to evaluate the indentation of materials by
considering both the force and displacement during plastic and elastic deformation. By monitoring the
complete cycle of increasing and removal of the test force, hardness values equivalent to traditional hardness
values can be determined. More significantly, additional properties of the material such as its indentation
modulus and elasto-plastic hardness can also be determined. All these values can be calculated without the
requirement to measure the indent optically. Furthermore, by a variety of techniques, the instrumented
indentation test allows to record hardness and modulus depth profiles within a, probably complex,
indentation cycle.
ISO 14577 (all parts) has been written to allow a wide variety of post test data analysis.
vi
DRAFT International Standard ISO/DIS 14577-3:2024(en)

Metallic materials — Instrumented indentation test for hardness and
materials parameters —
Part 3:
Calibration of reference blocks
1 Scope
This document specifies a method for the calibration of reference blocks to use for the indirect verification of
testing machines for the instrumented indentation test as specified in ISO 14577--2.
Reference materials, where it is necessary to prepare a surface before the test in a manner that removes
surface layers are excluded from this standard.
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 376, Metallic materials — Calibration of force-proving instruments used for the verification of uniaxial
testing machines
ISO 14577--1, Metallic materials — Instrumented indentation test for hardness and materials parameters —
Part 1: Test method
ISO 14577--2, Metallic materials — Instrumented indentation test for hardness and materials parameters —
Part 2: Verification and calibration of testing machines
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
4 Manufacture of reference blocks
4.1 4.1 The block shall be specially prepared and the attention of the manufacturer drawn to the
requirement to use a manufacturing process that gives the necessary homogeneity, uniformity, and stability
of structure. When the reference block is used for certifying hardness then it shall have a constant hardness
over the range of indentation sizes for which it is certified.
NOTE: Variation in hardness with variation in indentation size occurs when the microstructural length scale of the
material is within an order of magnitude of the indentation size. Microstructural length scale is in this circumstance the
combined frequency of all length scales in the material, for example grain size, precipitate spacing, layer thickness et
cetera.
4.2 4.2 Each block being calibrated shall be of a thickness greater or equal to that given in 0Table 1.
Table 1 — Thickness requirements for reference blocks
Range according to Thickness
ISO 14577-1:202X, 1. mm
Nano 2
Micro up to 500 mN 3
Micro up to 2 N 5
Macro up to 60 N 6
Macro up to 1 kN 12
Macro up to 30 kN 16
4.3 4.3 The reference blocks shall be free from magnetism. The manufacturers should ensure that the
blocks are demagnetized at the end of the manufacturing process.
4.4 4.4 The reference block shall be constructed such that it can be mounted in the testing machine.
For bottom mounted samples, the reference block shall have a flat bottom surface such that the sample to
stage interface contact does not contribute an additional frame compliance e.g. by deformation of asperities.
The sample bottom surface shall be perpendicular to the indentation direction when mounted and parallel to
the top surface so that the indentation tilt limits of ISO 14577-1 are met.
NOTE A 1° tilt is a slope of 0,175 mm per 10 mm sample length.
4.5 4.5 There shall be only one test surface on the block and the test surface shall be free from
scratches that interfere with the measurement of the indentations. Indentations between scratches are
permitted.
The surface roughness, Ra, shall not exceed 5 % of the minimum indentation depth specified for the CRM. The
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sampling length l for the roughness measurement (see ISO 21920 (all parts) Error! Reference source not
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found.) [2]) ) shall be larger than the indentation size. A sampling length of 0,80 mm is recommended. If
measured with an atomic-force-microscope (AFM), the sampling length, l, shall be at least 10 µm.
It is recommended to consider the spatial wavelength of the roughness as well as the amplitude.
4.6 4.6 In order to check that no material has been subsequently removed from the reference block,
its thickness at the time of calibration shall be marked on it to the nearest 10 µm or an identifying mark shall
be made on the test surface (see 8Clause 8).).
5 Calibrating machine
5.1 General
In addition to fulfilling the general conditions specified in ISO 14577--2, the calibrating machine shall also
meet the requirements listed in 5.25.2 to 5.55.5. The calibrating machine shall be calibrated and verified
directly at intervals not exceeding 24 months. Calibration and verification involve the following:
a) a) calibration of the test force;
b) b) verification of the indenter;
ISO/DISFDIS 14577-3:20252026(en)
c) c) calibration of the displacement measuring system;
d) d) it should meet the requirements of indirect verification according to ISO 14577-2: 20XX
Table 7
The instruments used for verification and calibration shall be traceable to the SI.
5.2 Calibration of the test force
The test force shall be calibrated according to ISO 14577-2:202X, 5.2 and shall be verified to have an
uncertainty at the 95 % confidence level less than
a) a) ±0,25 % for the macro range;
b) b) ±0,5 % for the micro range;
c) c) the larger of ±0,5 % or ±10 µN for the nano range.
The force shall be measured with elastic force-proving instruments of class 0,5 or better in accordance with
ISO 376 or by another method having the same accuracy.
5.3 Verification of the indenter
5.3.1 General
The certified measured values (e.g. angle, radius, etc.) of the indenter shall be used in all calculations and,
where indentation depth is ≤6 µm, the certified indenter area function with the relative uncertainty of less
than 5 % shall be used.
Verification of the certified measured values of the indenter shall be done by direct measurement in the macro
and micro range. In the low micro and nano ranges, it is recommended to use direct measurement for the
certified measured values where possible. The certified area function shall be verified by indentation into
reference materials certified for elastic modulus (e.g. by acoustics or flexural resonance).
In the nano and low micro ranges (h < 1 000 nm), the tolerances on the indenter angles are not normally
achieved. The sharpness of the tip is likely to have the most significant impact on the measurement of
hardness, but if an accurate area function is used, the tip shape has relatively little effect on the measurement
of the indentation modulus. It is difficult to determine the radius of curvature of an indenter to better
than ±10 nm as this is likely the radius of an AFM probe. Indentation methods using certified indentation
modulus reference blocks are easier for users, but give only a projected area value and do not specify its cross-
sectional shape.
Except for Martens Hardness blocks all certifications of the reference blocks shall be done via elastic modulus.
For all shapes of indenters, the tolerances given in ISO 14577--2:202X, 5.5.2, 5.5.3, 5.5.4, and 5.5.5 shall be met
as the minimum requirement.
The verification of the indenter tolerances requires a direct imaging and 3D shape measurement with suitable
instruments (e.g. Atomic Force Microscope).
5.3.2 Vickers indenter
The four faces of the square-based pyramid shall be highly polished, free from surface defects, and flat to
within 0,3 µm in the macro range and 0.,1 µm in the micro and nano range.
...