oSIST prEN ISO 148-3:2025

Metallic materials - Charpy pendulum impact test - Part 3: Preparation and characterization of Charpy V-notch reference certified test pieces for indirect verification of pendulum impact testing machines (ISO/DIS 148-3:2025)

ISO 148-3:2016 specifies the requirements, preparation and methods for qualifying test pieces used for the indirect verification of pendulum impact testing machines in accordance with ISO 148‑2.
It specifies notched test pieces with nominal dimensions identical to those specified in ISO 148‑1; however, the tolerances are more stringent.
NOTE 1 The chemical composition or heat treatment, or both, are varied according to the energy level desired.
NOTE 2 Reference test pieces are qualified on reference pendulum impact testing machines which are also described in this part of ISO 148.

Metallische Werkstoffe - Kerbschlagbiegeversuch nach Charpy - Teil 3: Vorbereitung und Charakterisierung von Charpy‑V-Referenzproben für die indirekte Überprüfung der Prüfmaschinen (Pendelschlagwerke) (ISO/DIS 148-3:2025)

Matériaux métalliques - Essai de flexion par choc sur éprouvette Charpy - Partie 3: Préparation et caractérisation des éprouvettes certifiées de référence Charpy à entaille en V pour la vérification indirecte des machines d'essai de choc pendulaire (ISO/DIS 148-3:2025)

ISO 148-3:2016 couvre les exigences, la préparation et les méthodes de qualification des éprouvettes utilisées pour la vérification indirecte des machines d'essai de flexion par choc (moutons-pendules) conformément à l'ISO 148‑2.
Elle décrit les éprouvettes à entaille, de dimensions nominales identiques à celles spécifiées dans l'ISO 148‑1. Cependant, les tolérances sont plus serrées.
NOTE 1 La composition chimique ou le traitement thermique, ou les deux, sont variables selon le niveau d'énergie de rupture choisi.
NOTE 2 Les éprouvettes de référence sont qualifiées sur des moutons-pendules de référence qui sont également décrits dans le présent document.

Kovinski materiali - Udarni preskus po Charpyju - 3. del: Priprava in ugotavljanje značilnosti V-zareznih preskušancev po Charpyju za posredno preverjanje udarnih naprav (ISO/DIS 148-3:2025)

General Information

• Status: Not Published
• Public Enquiry End Date: 30-Dec-2025
• ICS: 77.040.10 - Mechanical testing of metals
• Technical Committee: PKG - Testing of metallic materials
• Ref Project: prEN ISO 148-3 - Metallic materials - Charpy pendulum impact test - Part 3: Preparation and characterization of Charpy V-notch reference certified test pieces for indirect verification of pendulum impact testing machines (ISO/DIS 148-3:2025)

Relations

• Revises: SIST EN ISO 148-3:2017 - Metallic materials - Charpy pendulum impact test - Part 3: Preparation and characterization of Charpy V-notch test pieces for indirect verification of pendulum impact machines (ISO 148-3:2016)
• Effective Date: 04-Oct-2023

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2025
Kovinski materiali - Udarni preskus po Charpyju - 3. del: Priprava in ugotavljanje
značilnosti V-zareznih preskušancev po Charpyju za posredno preverjanje udarnih
naprav (ISO/DIS 148-3:2025)
Metallic materials - Charpy pendulum impact test - Part 3: Preparation and
characterization of Charpy V-notch reference certified test pieces for indirect verification
of pendulum impact testing machines (ISO/DIS 148-3:2025)
Metallische Werkstoffe - Kerbschlagbiegeversuch nach Charpy - Teil 3: Vorbereitung
und Charakterisierung von Charpy‑V-Referenzproben für die indirekte Überprüfung der
Prüfmaschinen (Pendelschlagwerke) (ISO/DIS 148-3:2025)
Matériaux métalliques - Essai de flexion par choc sur éprouvette Charpy - Partie 3:
Préparation et caractérisation des éprouvettes certifiées de référence Charpy à entaille
en V pour la vérification indirecte des machines d'essai de choc pendulaire (ISO/DIS 148
-3:2025)
Ta slovenski standard je istoveten z: prEN ISO 148-3
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.

DRAFT
International
Standard
ISO/DIS 148-3
ISO/TC 164/SC 4
Metallic materials — Charpy
Secretariat: ANSI
pendulum impact test —
Voting begins on:
Part 3: 2025-10-29
Preparation and characterization of
Voting terminates on:
2026-01-21
Charpy V-notch reference certified
test pieces for indirect verification
of pendulum impact testing
machines
ICS: 77.040.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 148-3:2025(en)
DRAFT
ISO/DIS 148-3:2025(en)
International
Standard
ISO/DIS 148-3
ISO/TC 164/SC 4
Metallic materials — Charpy
Secretariat: ANSI
pendulum impact test —
Voting begins on:
Part 3:
Preparation and characterization of
Voting terminates on:
Charpy V-notch reference certified
test pieces for indirect verification
of pendulum impact testing
machines
ICS: 77.040.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document has not been edited by the ISO Central Secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
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NOTIFICATION OF ANY RELEVANT PATENT
Phone: [phone]
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PROVIDE SUPPORTING DOCUMENTATION.
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 148-3:2025(en)
ii
ISO/DIS 148-3:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Definitions pertaining to the machine .1
3.2 Definitions pertaining to energy .2
3.3 Definitions related to groups of certified reference test pieces .2
3.4 Definitions pertaining to test pieces .3
4 Symbols and abbreviated terms. 4
5 Reference testing machine . 5
5.1 Characteristics.5
5.1.1 General .5
5.1.2 Geometrical characteristics (see Table 2 and Figures 1 and 2) .5
5.1.3 Capacity .6
5.1.4 Hardness .6
5.1.5 Vibration .6
5.1.6 Energy-indicating mechanism .6
5.2 Verification of a reference testing machine .6
6 Certified reference test pieces . 7
6.1 General .7
6.2 Material .7
6.3 Dimensions .7
6.4 Marking .7
6.5 Qualification of a batch of certified reference test pieces.8
6.6 Certified reference test piece sets .8
7 Certificates for certified reference test pieces . 8
8 Notes about the use of sets of certified reference test pieces . 9
Annex A (informative) Uncertainty of the certified K value of Charpy certified reference
V
materials .12
Bibliography . 19

iii
ISO/DIS 148-3:2025(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 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 World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/TC 164, Mechanical testing of metals, Subcommittee
SC 4, Toughness testing — Fracture (F), Pendulum (P), Tear (T).
This fourth edition cancels and replaces the third edition (ISO 148-3:2016), which has been technically
revised.
ISO 148 consists of the following parts, under the general title Metallic materials — Charpy pendulum impact test:
— Part 1: Test method
— Part 2: Verification of testing machines
— Part 3: Preparation and characterization of Charpy V-notch test pieces for indirect verification of pendulum
impact machines
— Part 4: Testing of miniature Charpy test pieces (in preparation).

iv
ISO/DIS 148-3:2025(en)
Introduction
The suitability of a pendulum impact testing machine for acceptance testing of metallic materials has
usually been based on a calibration of its scale and verification of compliance with specified dimensions,
such as the shape and spacing of the anvils supporting the test piece. The scale calibration is commonly
verified by measuring the mass of the pendulum and its elevation at various scale readings. This procedure
for evaluation of machines had the distinct advantage of requiring only measurements of quantities that
could be traced to national standards. The objective nature of these traceable measurements minimized the
necessity for arbitration regarding the suitability of the machines for material acceptance tests.
However, sometimes two machines that had been evaluated by the direct-verification procedures described
above, and which met all dimensional requirements, were found to give significantly different impact values
when testing test pieces of the same material.
This difference was commercially important when values obtained using one machine met the material
specification, while the values obtained using the other machine did not. To avoid such disagreements,
some purchasers of materials added the requirement that all pendulum impact testing machines used for
acceptance testing of material sold to them be indirectly verified by testing certified reference test pieces
supplied by them. A machine was considered acceptable only if the values obtained using the machine
agreed, within specified limits, with the value furnished with the certified reference test pieces.
Successful experience in the use of certified reference test pieces led to the requirement in ISO 148-2
that indirect verification should be performed using certified reference test pieces in addition to direct
verification. Other standards and codes also require indirect verification using certified reference test
[1]
pieces; for example, EN 10045-2 (now obsolete) and ASTM E23. The purpose of this part of ISO 148 is
to specify the requirements, preparation and methods for certifying test pieces used for the indirect
verification of pendulum impact testing machines.

v
DRAFT International Standard ISO/DIS 148-3:2025(en)
Metallic materials — Charpy pendulum impact test —
Part 3:
Preparation and characterization of Charpy V-notch reference
certified test pieces for indirect verification of pendulum
impact testing machines
1 Scope
This part of ISO 148 specifies the requirements, preparation and methods for qualifying certified reference
test pieces used for the indirect verification of pendulum impact testing machines in accordance with
ISO 148-2.
It specifies notched test pieces with nominal dimensions identical to those specified in ISO 148-1; however,
the tolerances are more stringent.
NOTE 1 The chemical composition or heat treatment, or both, are varied according to the energy level desired.
NOTE 2 Certified reference test pieces are qualified on reference pendulum impact testing machines which are also
described in this part of ISO 148.
2 Normative references
The following referenced 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 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 148-2, Metallic materials — Charpy pendulum impact test — Part 2: Verification of testing machines
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 Definitions pertaining to the machine
3.1.1
industrial machine
pendulum impact testing machine used for industrial, general or most research-laboratory testing of
metallic materials
Note 1 to entry: Industrial machines are not used to establish reference absorbed energy values for batches of certified
reference test pieces, unless they also meet the requirements of a reference machine (see Clause 5).

ISO/DIS 148-3:2025(en)
3.1.2
pendulum impact testing machine
testing machine equipped with a swinging hammer (pendulum) that is used to perform impact tests on
Charpy test pieces
Note 1 to entry: For the sake of simplicity, the term “machine” is often used in this document to generically indicate a
pendulum impact testing machine.
3.1.3
reference machine
pendulum impact testing machine used to determine reference values of absorbed energy for batches of
certified reference test pieces
3.2 Definitions pertaining to energy
3.2.1
total absorbed energy
K
T
total absorbed energy spent to break a test piece with a pendulum impact testing machine, which is not
corrected for any losses of energy
Note 1 to entry: It is equal to the difference in the potential energy from the starting position of the pendulum to the
end of the first half swing during which the test piece is broken.
3.2.2
absorbed energy
K
energy necessary to break a test piece with a pendulum impact testing machine, after correction for
energy losses
Note 1 to entry: The letters V or U are used to indicate the notch geometry, i.e. K or K . The numbers 2 or 8 are used as
V U
a subscript to indicate the radius of the striking edge of the striker, for example K or K .
V2 V8
3.2.3
reference absorbed energy
K
R
reference value of absorbed energy assigned to the certified reference test pieces used to indirectly verify
the performance of pendulum impact testing machines
3.2.4
initial potential energy
potential energy
K
p
potential energy of the machine hammer prior to its release for the impact test, as determined by direct
verification
3.2.5
nominal initial potential energy
nominal energy
K
N
energy assigned by the manufacturer of the pendulum impact testing machine
3.3 Definitions related to groups of certified reference test pieces
3.3.1
batch
definite quantity of certified reference test pieces manufactured under identical conditions of production,
with a common reference absorbed energy

ISO/DIS 148-3:2025(en)
3.3.2
set
group of certified reference test pieces chosen at random from a batch
3.3.2.1
characterization set
set of certified reference test pieces taken from a batch and used to determine the reference absorbed energy
of the batch
3.3.2.2
certified reference set
set of certified reference test pieces used to indirectly verify a pendulum impact testing machine
3.4 Definitions pertaining to test pieces
3.4.1
width
W
distance between the notched face and the opposite face
Note 1 to entry: Prior to 2016, the distance between the notched face and the opposite face was specified as “height”.
Changing this dimension to “width” makes ISO 148-1 consistent with the terminology used in other ISO fracture
standards.
3.4.2
thickness
B
dimension perpendicular to the width and parallel to the notch
Note 1 to entry: Prior to 2016, the dimension perpendicular to the width that is parallel to the notch was specified as
“width”. Changing this dimension to “thickness” makes ISO 148-1 consistent with the terminology used in other ISO
fracture standards.
3.4.3
length
L
largest dimension perpendicular to the notch
3.4.4
certified reference test piece
impact test piece accompanied by a certificate providing the reference absorbed energy value, K , and its
R
uncertainty at a stated level of confidence. It is used to verify the suitability of a pendulum impact testing
machine by comparing the indicated absorbed energy measured by that machine to the reference absorbed
energy associated with the certified reference test pieces
Note 1 to entry: The certified absorbed energy value is the value determined by a certified national or international
body, or by an organization accredited for the production of certified reference test pieces in accordance with
[2]
ISO 17034, following the procedures described in this part of ISO 148.

ISO/DIS 148-3:2025(en)
4 Symbols and abbreviated terms
Table 1 — Symbols/abbreviated terms and their designations and units
Symbol/
Unit Designation
abbreviated term
CRM — certified reference material
GUM — guide to the expression of uncertainty in measurement
k — coverage factor
K J absorbed energy
K J nominal initial potential energy or nominal energy
N
K J initial potential energy (potential energy)
p
K J reference absorbed energy of a set of Charpy certified reference test pieces
R
K J total absorbed energy
T
K J absorbed energy as measured in accordance with ISO 148-1 on a V-notched sample
V
KV value as determined for a batch of V-notched Charpy reference specimens in a
K J
Vchar
batch certification characterization exercise
K J certified K value of a PB certified reference material
VPB V
K J certified K value of a Charpy certified reference material
VR V
K J certified K value of an SB certified reference material
VSB V
n — number of samples tested for the homogeneity assessment
hom
n — number of PB test pieces used to compare SB with PB
PB
n — number of SB test pieces used to compare SB with PB
SB
number of certified reference samples tested for the indirect verification of a pen-
n —
V
dulum impact testing machine
p — number of laboratories/instruments participating in a laboratory comparison
PB — primary batch
REMCO — ISO Committee on Reference Materials
SB — secondary batch
standard deviation of the K values obtained on n samples in the homogeneity
V hom
s J
CRM
assessment of the batch of certified reference material
s J standard deviation of the mean K values obtained at p laboratories
p V
standard deviation of results obtained on n PB samples when comparing them
PB
s J
PB
with n SB samples
SB
u J standard uncertainty of KV
char char
u J standard uncertainty of KV for a PB
char,PB char
u J standard uncertainty of KV for an SB
char,SB char
standard uncertainty of the reference absorbed energy value of a certified refer-
u J
CRM
ence material used for indirect verification
expanded uncertainty of the reference absorbed energy value of a certified refer-
U J
CRM
ence material at a confidence level of about 95 %
standard uncertainty of the homogeneity assessment of the certified reference
u J
hom
material
standard uncertainty of the long-term-stability assessment of the certified refer-
u J
lts
ence material
standard uncertainty of the short-term-stability assessment of a certified refer-
u J
sts
ence material
u
J
standard uncertainty of X
PB
XPB
u
J
standard uncertainty of X
SB
XSB
ISO/DIS 148-3:2025(en)
TTabablele 1 1 ((ccoonnttiinnueuedd))
Symbol/
Unit Designation
abbreviated term
J mean of n test pieces used to compare SB with PB
X
PB
PB
J mean of n test pieces used to compare SB with PB
X
SB SB
δK J part of the error of the measured K value due to batch heterogeneity
Vhom V
δK J part of the error of the measured K value due to long-term instability
Vlts V
δK J part of the error of the measured K value due to short-term instability
Vsts V
v — degrees of freedom corresponding to u
char char
v — degrees of freedom corresponding to u
hom hom
v — degrees of freedom corresponding to u
CRM CRM
5 Reference testing machine
5.1 Characteristics
5.1.1 General
The characteristics of reference machines used to determine the certified absorbed energy of certified
reference test pieces shall comply with the requirements of ISO 148-2, except as modified below.
5.1.2 Geometrical characteristics (see Table 2 and Figures 1 and 2)
The following geometrical characteristics apply:
+01, 0
a) the radius of the anvils shall be 1 mm ;
()
00, 0
+01, 0
b) the distance between the anvils (span) shall be 40 mm ;
()
00, 0
c) the striking edge shall be within ±0,25 mm of the plane of symmetry of the anvils.
Table 2 — Geometrical characteristics of a reference testing machine
Reference
Designation Value Tolerance Units
a
number
+0,00
1 Length of test piece 55,00 * mm
−0,30
2 Notch position (centring) 27,5 ±0,2 * mm
3 Width of test piece 10,00 ±0,06 * mm
4 Thickness of test piece 10,00 ±0,07 * mm
5 Ligament width 8,00 ±0,06 * mm
6 Angle of notch 45,0 ±1,0 * °
7 Notch root radius 0,250 ±0,025 mm
8 Angle between adjacent faces 90,00 ±0,15 * °
Angle between plane of symmetry of notch and longitudinal
9 90 ±2 °
axis of test piece
+0,10
10 Radius of anvils 1,00 * mm
−0,00
NOTE 1 Tolerances followed by an asterisk * are tighter than those in ISO 148-1 or ISO 148-2.
NOTE 2 See Figures 1 and 2.
a
See Figure 1.
ISO/DIS 148-3:2025(en)
TTabablele 2 2 ((ccoonnttiinnueuedd))
Reference
Designation Value Tolerance Units
a
number
11 Angle of taper of anvils 11 ±1,0 °
+0,10
12 Distance between anvils (span) 40,00 * mm
−0,00
13 Distance of striking edge from plane of symmetry of anvils — ±0,25 * mm
14 Angle of striker 30 ±1 °
+0,20
15A Radius of striking edge of 2 mm striker 2,00 * mm
−0,00
15B Radius of striking edge of 8 mm striker 8,00 ±0,05 mm
+0,50
15C Radius of shoulder of 8 mm striker 0,25 mm
−0,05
15D Width of striking edge of 8 mm striker 4,00 ±0,05 mm
NOTE 1 Tolerances followed by an asterisk * are tighter than those in ISO 148-1 or ISO 148-2.
NOTE 2 See Figures 1 and 2.
a
See Figure 1.
5.1.3 Capacity
The capacity of a reference machine (nominal initial potential energy) shall be appropriate for the test pieces
to be tested and certified. Certified energies shall not exceed 80 % of the machine capacity.
5.1.4 Hardness
The portions of the striker and the anvils (see Figure 1) that contact the test piece and apply or react to the
impacting force shall have a minimum hardness of 56 HRC.
5.1.5 Vibration
Ensure that the reference machine is not subjected to external vibrations induced by other equipment
in close proximity, such as forging hammers, presses, moving vehicles. The machine shall also be free of
excessive vibrations during an impact test.
NOTE Such vibrations can be detected by placing a small container of water at any convenient location on the
machine framework; the absence of ripples on the water surface during an impact test indicates that this requirement
has been met. Excessive vibration in a machine firmly fastened to the floor indicates the need for a separate foundation
and/or the use of vibration isolators.
5.1.6 Energy-indicating mechanism
The resolution shall be at least 0,25 % of the nominal energy.
5.2 Verification of a reference testing machine
Direct verification shall be carried out in accordance with ISO 148-2 and with the additional requirements of 5.1.
Indirect verification shall be carried out using certified reference test pieces. At least 10 certified reference
test pieces shall be tested. The repeatability and the bias shall be as specified in Table 3.
All equipment used for inspection and verification of a reference testing machine shall be calibrated and
shall have a certified traceability to the SI System (the international system of units). The body performing
the verification shall maintain calibration records for all inspection, measurement and test equipment.
The dates and details of all inspections and repairs shall be documented and maintained for each reference
machine by the owner of the machine.

ISO/DIS 148-3:2025(en)
Table 3 — Repeatability and bias of reference pendulum impact testing machines
Absorbed energy Repeatability Allowed bias
K
< 40 J ≤ 2 J ±2 J
≥ 40 J ≤ 5 % of K ±5 % of K
R R
Repeatability is the standard deviation of the K values measured on a least 10 certified reference test pieces.
R
Bias is given by KK− ,
R
where:
KK ++ KK ++.
12 3 n
K = ,
n
with n ≥ 10.
6 Certified reference test pieces
6.1 General
Guidelines for the preparation, certification, and use of (certified) reference materials have been drawn
up by ISO REMCO, the ISO Committee on reference materials (see References [2] to [6]). The procedures
described below provide more details, specific to t
...