The certification of the absorbed energy (120 J nominal) of Charpy V-notch reference test pieces for tests at 20 °C : ERM®-FA016bp : certification report.
Date: 2023-05-23
Institutions: Joint Research Centre
Subjects: Community certification, evaluation method, metal product, research report, resistance of materials, testing

ISSN 1831-9424 

Certification of the absorbed energy (120 J 
nominal) of Charpy V-notch reference test pieces 
for tests at 20 °C: ERM®-FA016bp

T. Linsinger, F. Vanderveken

2023 

EUR 31501 EN 

This publication is a Reference Materials report by the Joint Research Centre (JRC), the European Commission’s science and knowledge 
service. It aims to provide evidence-based scientific support to the European policymaking process. The contents of this publication do 
not necessarily reflect the position or opinion of the European Commission. Neither the European Commission nor any person acting on 
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Contact information  
Name: EC, Joint Research Centre, Directorate F – Health and Food, Reference Materials Unit 
Address: Retieseweg 111, 2440 Geel, Belgium 
Email: JRC-RM-DISTRIBUTION@ec.europa.eu 
Tel.: 0032/14/571722 
Website : https://crm.jrc.ec.europa.eu 

EU Science Hub 
https://joint-research-centre.ec.europa.eu 

JRC133377 

EUR 31501 EN 

PDF  978-92-68-03188-9 

ISSN 1831-9424 

doi:10.2760/31020  KJ-NA-31-501-EN-N 

Luxembourg: Publications Office of the European Union, 2023  

© European Union, 2023 

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How to cite this report: F. Vanderveken, T. Linsinger, Certification of the absorbed energy (120 J nominal) of Charpy V-notch reference 
test  pieces  for  tests  at  20  °C:  ERM®-FA016bp,  Publications  Office  of  the  European  Union,  Luxembourg,  2023,  doi:10.2760/31020, 
JRC133377. 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Contents 

Abstract ................................................................................................................................................................................................................ 1 

Acknowledgements....................................................................................................................................................................................... 2 
Introduction .......................................................................................................................................................................................... 3 
1 
Participants .......................................................................................................................................................................................... 7 
2 
Material processing and process control ........................................................................................................................... 8 
3 
Homogeneity .................................................................................................................................................................................... 10 
4 
Stability ................................................................................................................................................................................................ 11 
5 
Characterisation ............................................................................................................................................................................. 12 
6 
Value assignment ......................................................................................................................................................................... 15 
7 
Metrological traceability and commutability ............................................................................................................... 16 
8 
9 
Instructions for use ...................................................................................................................................................................... 18 
10  Conclusions ....................................................................................................................................................................................... 19 
References ...................................................................................................................................................................................................... 20 
List of abbreviations and definitions ............................................................................................................................................. 22 
List of boxes .................................................................................................................................................................................................. 23 
List of figures ................................................................................................................................................................................................ 24 
List of tables .................................................................................................................................................................................................. 25 
Annex 1 ............................................................................................................................................................................................................. 26 
Annex 2 ............................................................................................................................................................................................................. 27 

i 

Abstract 
This certification report describes the processing and characterisation of ERM®-FA016bp, a batch of Charpy V-
notch alloy steel certified reference test pieces certified for the average absorbed energy (KV). Sets of five of 
these test  pieces are  used for the indirect verification of pendulum impact test machines according to ISO 
148-2 [1].
KV  is  operationally  defined  and  refers  to  the  impact  energy  required  to  break  a  V-notched  test  piece  of
standardised dimensions, as defined in ISO 148-1 [2]. The certified value of ERM-FA016bp is made traceable
to  the  International  System  of  Units  (SI),  via  the  SI-traceable  certified  value  of  the  master  batch  ERM®-
FA016ax [3], by testing test pieces of ERM-FA016bp and ERM-FA016ax  under repeatability conditions on a
Charpy  reference  pendulum  verified  and  calibrated  with  SI-traceably  calibrated  tools.  The  certified  value  is
valid only for strikers with a 2 mm tip radius. The certified value is valid at (20 ± 2) °C.

The certified value for KV and the associated expanded uncertainty (k = 2 corresponding to a confidence level 
of about 95 %) were calculated in accordance with ISO 17034:2016 [4] and ISO Guide 35:2017 [5] for the 
mean  of  a  set  of  five  test  pieces.  The  uncertainty  includes  contributions  related  to  possible  inhomogeneity 
and  characterisation.  Before  release  of  the  certified  reference  material,  the  certification  project  was 
subjected to peer-review. 

1 

Acknowledgements  
The authors would like to acknowledge the support received from colleagues of JRC for the measurements 
and the review of the certification project. 

Authors 
Francine Vanderveken1, Thomas Linsinger1 
1) European Commission, Joint Research Centre, Directorate F, Geel, BE 

2 

 
 
 
 
 
1 

Introduction 

1.1  Background  
Steel (in history books called “iron”) replaced bronze as most widely used metal for tools about 2800 years 
ago.  While  the  use  of  steel  as  a  base  material  for  tools  and  weapons  is  ancient,  the  use  of  steel  for 
construction  is  rather  recent,  with  the  C&A  Bridge  over  the  Missouri  River  (Glasgow,  Missouri,  USA)  built  in 
1879  being  one  of  the  early  examples.  Also  the  use  of  reinforced  concrete  dates  back  only  to  the  19th 
century, with a cottage built in 1854 by William B. Wilkinson quoted as the first use. A third use of steel is for 
pressure vessels like the ones used in power plants, nuclear reactors, but also fire extinguishers or spray cans 
etc. This wide variety of use is due to the fact that the hardness and ductility of steel can be adjusted to the 
intended  use  by  appropriate  heat  treatment.  Because  the  properties  of  steel  can  be  changed  over  a  wide 
range and because of the fact that steel is cheap, steel is the most widely traded metal world-wide. 

In  order  to  design  buildings  and  equipment  efficiently  and  safely,  knowledge  of  the  properties  of  the  steel 
used  are  needed.  In  the  European  Union  (EU)  harmonised  technical  rules  specifying  how  structural  design 
should  be  conducted  exist  (“Eurocodes”)  [6,  7;  8]  and  all  public  works  must  adhere  to  these  standards  [9]. 
Furthermore,  harmonised  conditions  for  the  marketing  of  construction  products  in  the  EU  have  been 
established  [10]  and  legal  requirements  for  pressure  equipment  exist  in  the  EU  [11].  These  laws,  partly 
through the mandatory standards they refer to, set mandatory requirements for steel used.  

One of these requirements concerns the impact toughness of  steel, which is the energy needed to break a 
piece of steel of specified dimensions. This basic principle of this test (“Charpy test”) is outlined in section 1.2. 
Two international standards describe the test, namely the ISO-148 series [1, 2] and ASTM E23-18 [12]. The 
two standards describe the same principle, but differ slightly in the specification of some building blocks of 
the testing machine. Both standards require users of testing machines to regularly check the performance of 
their equipment by using certified reference materials (CRMs). 

This means that the use of certified reference materials for Charpy testing is, via ISO 148 and EU legislation 
that mandates the use of ISO-148, a legal requirement in the EU and the CRMs are required to implement EU 
legislation (Figure 1). 

Figure 1. Relation between EU legislation and the availability of Charpy CRMs. 

Apart from the legal aspect,  these CRMs also support the common internal market: as testing according to 
ISO-148 is required in the EU, the impact toughness of steel is one of the specifications of steel. The use of 
these CRMs make measurements more reliable and therefore support the EU Common market and the free 
movement of goods. 

Thirdly, accurate knowledge of the physical properties of construction materials allows using smaller safety 
margins  for  the  amount  of  material  used  while  still  achieving  the  same  safety.  For  example,  it  has  been 
estimated that using modern steel, the Eiffel tower could be built with 1/3 of the material that was needed in 
1887. In this way, the use of Charpy CRMs also contribute to the European Green Deal and the New European 
Bauhaus. 

Continuous availability of Charpy CRMs is therefore in the interest of EU legislators, European companies and 
European citizens. 

3 

 
 
1.2  The Charpy pendulum impact test 
The Charpy pendulum impact test is designed to assess  the  resistance of a material  to shock loading. The 
test consists of breaking a notched test piece of the test material using a hammer rotating around a fixed 
horizontal axis and is schematically presented in Figure 2. 

Figure 2. Schematic presentation of the Charpy pendulum impact test, showing a: the horizontal rotation axis of the 
pendulum, b: the stiff shaft on to which is fixed d: the hammer. The hammer is released from a well-defined height 
(position 1). When the hammer has reached maximum kinetic energy (shaft in vertical position 2), the hammer strikes c: 
the test piece, which is positioned on a support and against the pendulum anvils (not shown). The height reached by the 
hammer after having broken the test piece (position 3) is recorded. The difference in height between position 1 and 3 
∆
h) corresponds with a difference in potential energy, and is a measure of the energy required to break the test piece. 
(

b
b

1
1

d
d

2
2

∆h
∆h

a
a

3
3

c
c

The  energy  absorbed  by  the  test  piece  is  very  dependent  on  the  impact  pendulum  construction  and  its 
dynamic behaviour. Methods to verify the performance of an impact pendulum require the use of reference 
test  pieces  as  described  in  ISO  and  other  international  documentary  standards  [1,  12].  The  reference  test 
pieces  dealt  with  in  this  report  comply  with  a  V-notched  test  piece  shape  of  well-defined  geometry  [2], 
schematically shown in Figure 3. 

Figure 3. Schematic drawing of a V-notched Charpy test piece (top-view), indicating the place and direction of impact 
and the position of the anvils. 

anvil
anvil

anvil
anvil

sample
sample

location and direction of impact
location and direction of impact

4 

 
 
 
 
 
 
 
 
1.3  The certification concept of Master Batch and Secondary Batch 

1.3.1  Difference between Master and Secondary Batches 
The BCR reports by Marchandise et al. [13] and Varma [14] provide details of the certification of BCR “Master 
Batches”  (MB)  of  Charpy  V-notch  certified  reference  test  pieces.  The  certified  value  of  a  Master  Batch  is 
obtained using an interlaboratory comparison (ILC).  
This report  describes the  production of a “Secondary  Batch” (SB) of Charpy  V-notch certified reference test 
pieces at the Directorate F – Health and Food of the European Commission's (EC) Joint Research Centre (JRC). 
The  work  was  performed  in  accordance  with  procedures  described  in  the  BCR  reports  [7]  and  [8].  The 
certification of a SB is based on the comparison of a set of SB test pieces with a set of test pieces from the 
corresponding MB under repeatability conditions on a single pendulum.  
The BCR reports [7] and [8] were published in 1991 and 1999, respectively. Since 2000, the calculation of the 
certified value and the estimation of its uncertainty have been updated to an approach compliant with ISO 
17034:2016  [4]/  ISO  Guide  35:2017  [5]  and  the  ISO/IEC  Guide  to  the  Expression  of  Uncertainty  in 
Measurement [15], respectively. This revised approach was developed and presented by Ingelbrecht et al. [16, 
17], and is summarised below.  

1.3.2  Certification of a Secondary Batch of Charpy V-notch test pieces 
The certified absorbed energy of a SB of Charpy V-notch reference test pieces (KVCRM) is calculated from the 
mean  KV-value  of  a  set  of  SB  test  pieces  (
  has  to  be 
corrected for the  bias of this particular pendulum. The  bias of the pendulum at the  moment of testing the 
test pieces of the SB, is estimated by comparing the mean KV-value of a number of test pieces of the MB  
( MBX ), tested together with the SB test pieces under repeatability conditions, with the certified value of the MB 
(KVMB). KVCRM is then calculated as follows [17]: 

)  tested  on  a  single  pendulum.  This  value 

SBX

SBX

KV

CRM

=

MB


KV

X


MB

⋅

X

SB





Equation 1 

For this approach to be reliable, the pendulum  used  for the tests on MB and SB in repeatability conditions, 
  must  be  close  to  1.  ISO 148-3  [18]  allows  a 
must  be  well  performing.  In  other  words,  the  ratio 

MB

KV
X

MB

difference of 5 % (KVMB ≥ 40 J) or 2 J (KVMB < 40 J) between KVMB and  MBX ,. 

composition.  Moreover,  it  is  checked  that  the  ratio 

For  reasons  of  commutability,  a  comparable  response  of  the  pendulum  to  the  MB  and  SB  test  pieces  is 
required. This is the reason why MB and SB test pieces are made from steel with a closely-matched chemical 
KV
KV
difference of 20 % (KVMB ≥ 40 J) or 10 J (KVMB < 40 J) between KVCRM and KVMB to ensure that the MB and SB 
test pieces have a comparable interaction with the pendulum. 

  is  close  to  1.  Procedures  at  the  JRC  allow  a 

CRM

MB

1.3.3  Uncertainty  of  the  certified  value  of  a  Secondary  Batch  of  Charpy  V-notch  test 

pieces 

MBX /

SBX .  The  full  measurement  uncertainty  of  the  values 

The uncertainty of the certified value of the SB is a combination of the uncertainties of the right-hand side 
factors in Equation 1. It is clear that the  MB-SB approach  necessarily  results in a larger  uncertainty of the 
certified value of the SB in comparison with the MB. The additional uncertainty depends on the uncertainty of 
SBX   is  relatively  large.  However, 
the  ratio 
when  all  conditions  mentioned  above  (repeatability  conditions,  pendulum  performance,  and  commutability 
SBX   have 
between  Secondary  and  Master  Batch)  are  fulfilled,  then  the  uncertainties  of  the  values 
several contributions in common, in particular the uncertainty due to the bias of the pendulum. These shared 
SBX ,  and  only  the  standard 
uncertainty  components  do  not  contribute  to  the  uncertainty  of  the  ratio 
deviations of the SB and MB results in the MB-SB comparison test need to be taken into account (see also 
Section 6.3). Thus, the MB-SB comparison approach can produce a value for the uncertainty of KVCRM that is 
sufficiently small to meet the requirements of the intended use of the CRM.  

MBX   and 

MBX   and 

MBX /

5 

 
 
   
 
 
 
 
 
 
1.4  Choice of the material 
Steel is one of the most frequently used materials worldwide. The impact toughness of structural steel is one 
important property for planning buildings and equipment. Consequently, testing of the impact toughness of 
the  steel  used  is  required  in  legislation,  for  example  the  EU  legislation  on  construction  products  [10]  and 
pressure equipment [11]. Steel is therefore the material most often tested by ISO 148 and is therefore the 
material of choice for a CRM. 
The validity of the MB-SB approach to characterisation requires that both MB and SB have similar breaking 
behaviour,  meaning  that  similar  amounts  of  energy  are  absorbed  by  actually  breaking  the  sample  and  by 
ductile deformation. Apart from the energy level itself, the chemical composition contributes to the amount 
of ductile deformation. As the MB is an AISI4340/1.6565 type steel, also an AISI4340/1.6565 type steel was 
chosen for the SB. 

1.5  Outline of the CRM project 

Box 1. Reference material production 

Reference  material  (RM)  production  is  defined  in  ISO  17034  [4]  as  a  project  comprising  planning  and 
processing of the material, followed by homogeneity and stability testing, characterisation and assigning of 
one or more property values. Depending on the intended use of the RM a commutability study is carried out. 

For certified reference materials (CRMs) a certificate is issued while for RMs a product information sheet is 
issued by the reference material producer (RMP). 

CRMs and RMs are distributed globally and the stability of their assigned values is monitored throughout the 
life-time of the material. 

Certain commercial equipment, instruments, and materials are identified in this report to specify adequately 
the  experimental  procedure.  In  no  case  does  such  identification  imply  recommendation  or  endorsement  by 
the European Commission, nor does it imply that the material or equipment is necessarily the best available 
for the purpose. 

The characterisation principle applied is characterisation by direct comparison with an existing CRM (primary 
batch or MB), as described in 1.3.  
The uncertainty of the certified value was estimated in compliance with ISO 17034 [4], which implements the 
basic principles of ISO/IEC Guide 98 (GUM) [15]. 
The CRM project, including the certification approach and the evaluation of the obtained measurement data, 
was subjected to peer-review. 

6 

 
 
 
 
2  Participants 

2.1  Project management and data evaluation 
European Commission, Joint Research Centre, Directorate F – Health and Food, Unit F.6 (Reference Materials), 
Geel, BE  
(accredited to ISO 17034:2016 for production of certified reference materials, BELAC No. 268-RM) 

2.2  Processing 
Institut für Eignungsprüfung GmbH (IfEP), Marl (DE)   
(accredited  to  DIN  EN  ISO  17034:2016  for  production  of  certified  reference  materials,  DAkkS  No.  D-RM-
11183-01-00) 

2.3  Homogeneity measurements 
Institut für Eignungsprüfung GmbH (IfEP), Marl (DE) 

2.4  Characterisation measurements 
Laboratoire National de Métrologie et D’Essais (LNE), Trappes (FR) 
(measurements under the scope of ISO/IEC 17025:2017 accreditation COFRAC 2-1287) 

7 

 
 
 
 
3  Material processing and process control 

Box 2. Reference material processing 

RM processing covers the raw material conversion into a homogenous 
and  stable  material.  In  the  case  of  Charpy  test  pieces,  this  includes 
cutting of test pieces, heat treatment and creating the V-notch as well 
as assembling sets of five test pieces and packaging of the sets. 

3.1  Origin of the starting material 
The  ERM-FA016bp  test  pieces  were  prepared  from  bars  of  AISI4340/1.6565  steel  produced  by  Tata  Steel 
International Germany GmbH. One round bar with a length of 3.2 m was cut into 55 discs. These discs were 
normalised at 900 °C for 150 minutes.. 

3.2  Processing 

3.2.1  Machining of Charpy test pieces 
Machining of the test pieces was performed by IfEP. 14 discs were selected to machine the test pieces, were 
cut  into  1715  Charpy  test  pieces  and  engraved  to  ensure  identification  but  not  yet  machined  to  the 
dimensional requirements of ISO 148-3 [18]. 

3.2.2  Heat treatment of hot-rolled bars 
The heat treatment to obtain the desired energy level of the test pieces was performed at VTN Witten GmbH 
(Witten, DE) in a vacuum-furnace. 1715 test pieces of the batch were heat-treated according to the following 
procedure: 

Step 1: hardening at 850°C for 90 minutes 
Step 2: quenching with oil 
Step 3: first tempering at 610 °C for 180 minutes 
Step 4: cool down in air 
Step 5: second tempering at 610 °C for 180 minutes 
Step 6 cool down in air 

For the heat treatment, the test pieces were distributed over three baskets. The baskets were stacked in the 
furnace  equipped  with  a  thermocouple  to  monitor  the  temperature.  The  measured  temperature  was  within 
the tolerance of ± 6 °C as required by IfEP. 

3.2.3  Final machining of Charpy test pieces 
After heat treatment, the test pieces were machined to the final dimensions specified in ISO 148-3 [18] by 
IfEP.  During  this  process  the  test  piece  numbers  were  engraved  on  one  of  the  end  faces.  Finally  the  test 
pieces were notched using a milling process. 

3.2.4  Packaging and storage 
The  test  pieces  were  cleaned  and  assembled  in  sets  of  five  randomised  test  pieces  and  wrapped  in 
anticorrosion paper. These wrapped sets were packed in a sealed plastic bag, and shipped to the JRC (Geel, 
BE).  After  arrival,  the  1470  test  pieces  (or  294  sets)  of  ERM-FA016bp  were  registered  and  stored  at  room 
temperature, pending distribution. 

8 

 
 
 
 
 
 
 
 
For the purpose of this report, the term ‘unit’ refers to one set of five Charpy impact test specimens  of ERM-
FA016bp. 

3.3  Process control 
When all test pieces from the batch were fully machined, a random selection of 25 test pieces from across 
the whole batch was made. The dimensions of the 25 test pieces were checked against the criteria specified 
in ISO 148-3 [18]: length (55.0 +0.00/-0.30) mm, height (10.00 ± 0.06) mm, width (10.00 ± 0.07) mm, notch 
angle  45 ± 1°,  height  remaining  at  notch  root  (8.00 ± 0.06 )mm,  radius  at  notch  root  (0.250 ± 0.025) mm. 
None of the test pieces was outside the ranges specified in ISO 148-3 [18].  

25  test  pieces  were  then  impact  tested  using  a  pendulum  type  Zwick  PSW  750  (nominal  energy  450  J), 
verified in 2017 according to ISO 148-2 [1]. 
The tests were performed on 16/05/2019. The results are reported in the production report of IfEP [19]. The 
average KV of the 25 test pieces was 115.95 J, which is within the desired energy range (112.5 J - 127.5 J). 
The  standard  deviation  of  the  test  results  (s  =  2.66 J,  RSD  =  2.29 %)  was  below  the  3.0  %  acceptance 
criterion.  

The variation was checked again during the characterisation tests (see Section 6). 

9 

 
 
 
 
 
 
4  Homogeneity 

Box 3. Homogeneity assessment 

A  key  requirement  for  any  RM  produced  as  a  batch  of  units  is 
equivalence  between  those  units.  It  is  important  to  know  how  much 
the  variation  between  units  contributes  to  the  uncertainty  of  the 
certified value. Consequently, ISO 17034 [4] requires RMPs to quantify 
the between-unit variation in homogeneity studies. 

The  within-unit  homogeneity  is  correlated  to  the  minimum  sample 
size,  which  is  the  minimum  amount  of  sample  that  is,  for  a  given 
measurand, representative of the whole unit and that should be used 
in  an  analysis.  Using  sample  intakes  equal  to  or  above  the  minimum 
sample  size  guarantees  the  assigned  value  within 
its  stated 
uncertainty. The concept of within-unit homogeneity does not apply to 
Charpy test specimens, as no subsampling is possible. 

The  test  pieces  are  sampled  from  the  SBs,  which  should  be  sufficiently,  but  are  never  perfectly, 
homogeneous. Therefore, an appropriate homogeneity contribution uh to the uncertainty of the certified value 
is  required.  uh  is  related  to  sh,  the  standard  deviation  between  the  test  pieces  in  the  SB  (test  piece-to-test 
piece  heterogeneity),  but  also  depends  on  the  number  of  test  pieces  over  which  the  KV-value  is  averaged. 
ISO 148-2 [1] specifies that the pendulum verification must be performed using five test pieces, which is why 
a CRM unit consists of a set of five test pieces. The appropriate uncertainty contribution must be an estimate 
of the set-to-set heterogeneity (uh), which in the case of a set of five test pieces can be calculated as 

u =
h

s

h

5

Equation 2 

For  the  assessment  of  homogeneity,  the  measurements  performed  at  IfEP  on  16/05/2019  during  process 
control  were  used.  As  required  for  a  homogeneity  test,  the  test  pieces  were  randomly  selected  from  the 
whole batch. The number of test pieces tested (25) is sufficiently large to reflect the homogeneity of the full 
SB (1470 test pieces). The results are depicted in Annex 1. 

Here, uh is estimated from sh, the standard deviation results obtained (sh = 2.66 J). This leads to  

u =
h

s

h

5

= 

1.19 J (1.02 %).  
It  can  be  noted  that  uh  is  probably  a  slight  overestimation,  since  it  contains  also  the  repeatability  of  the 
instrument. However, the latter cannot be separated or separately measured. 

10 

 
 
 
  
 
 
 
 
 
 
 
5  Stability 

Box 4. Stability assessment 

Stability testing is necessary to establish the conditions 
for  storage  as  well  as  the  transport  conditions  of  the 
RMs  to  the  customers.  During  transport,  especially  in 
summer, temperatures up to 60 °C can be reached, and 
stability  under  these  conditions  must  be  demonstrated 
if the RMs are to be transported without any additional 
cooling. 

The stability of the absorbed energy of Charpy V-notch certified reference test pieces was first systematically 
investigated for test pieces of nominally 120 J by Pauwels et al., who did not observe measurable changes of 
absorbed  energy  [20].  Additional  evidence  for  the  stability  of  the  reference  test  pieces  produced  from 
AISI 4340 steel of lower energy levels (nominally 15 J, 30 J and 100 J) was obtained during the International 
Master Batch (IMB) project [21]. In the IMB-project, the stability of the certified test pieces was judged from 
the  change of the  mean of  means of the absorbed energy obtained on seven reference  pendulums over a 
three year period. None of the three regression slopes for the tested energy levels was statistically significant 
at the 5 % probability level. Given the large test piece-to-test piece heterogeneity and the limited number of 
test  pieces,  five  in  a  CRM  unit,  the  uncertainty  contribution  from  instability  is  considered  insignificant  in 
comparison  to  that  of  homogeneity.  A  dedicated  isochronous  study  (test  temperature  18  °C,  reference 
temperature -20 °C)  was organised by the JRC  using batches of 30 J, 80 J and  120 J  from the same steel 
and  showed,  as  expected,  no  significant  change  of  the  measured  values.  Uncertainty  of  stabilities  for  120 
months  were  calculated  as  0.7  J  -  2.8  J  (1.8  %  -  2.4  %).  These  uncertainties  are  entirely  driven  by  the 
measurement  precision  and  it  was  concluded  that  no  uncertainty  contribution  for  potential  change  was 
needed [22]. 
The  main  reason  for  the  microstructural  stability  of  the  certified  reference  test  pieces  is  the  annealing 
treatment to which the test pieces were subjected after the austenisation treatment. Annealing is performed 
at  temperatures  where  the  equilibrium  phases  are  the  same  as  the  (meta-)stable  phases  at  ambient 
-Fe and Fe3C). The only driving force for instability stems from the difference in solubility of 
temperature (
interstitial elements in the 
-Fe matrix, between annealing and ambient temperature. Relaxation of residual 
(micro-)stress by short-range diffusion or the additional formation or growth of precipitates during the shelf-
life of the certified reference test pieces is expected to proceed but slowly.  

α

α

Rather  than  neglecting  the  stability  issue,  efforts  are  spent  to  better  establish  the  stability  of  the  certified 
values  of  batches  of  Charpy  CRMs.  Until  such  further  notice,  it  is  decided  to  specify  a  limited  shelf-life.  A 
period  of  10  years  is  chosen,  counting  from  the  date  of  the  characterisation  tests  on  the  SB.  Since  batch 
ERM-FA016bp was characterised on 13/01/2023, the certificate is valid until 1/2033.  

11 

 
 
 
 
 
 
 
 
6  Characterisation 

Box 5. Reference material characterisation 

Material characterisation is the process of determining the property value(s) 
of  a  RM.  While  ISO  17034  [4]  allows  to  characterise  a  RM  in  various  ways. 
Quality  management  procedures  of  the  JRC  are  more  stringent  and  allow 
characterisation  only  by  either  interlaboratory  comparison,  the  use  of  a 
primary method confirmed by independent analysis or value transfer using a 
single measurement method in a single laboratory. 

The  material  characterisation  was  based  on  value  transfer  from  the  MB  to  the  SB  using  a  single 
measurement method (ISO 148-1) in a single laboratory.. This approach is valid as long as the two materials 
are certified for the same measurand and as long as the two materials are very similar. 
The first condition is fulfilled as both MB and SB are certified for absorbed energy according to ISO-148-3 
[18].  The  second  condition  is  fulfilled  as  the  SB  and  MB  are  from  equivalent  steel  types  with  relative  low 
differences in the absorbed energy between SB and MB. Therefore, the measurement of the MB can indeed 
correct for undetected biases in the measurement of the SB. 

6.1  Study setup 
30  test  pieces  from  ERM-FA016bp  (sets  14,  84,  124,  162,  243,  276)  were  tested  under  repeatability 
conditions together with 25 test pieces from MB ERM-FA016ax [3] (sets 45, 46, 50, 54, 59), using the TINIUS 
OLSEN type 74 impact machine at LNE, a Charpy reference pendulum yearly verified according to procedures 
described in ISO 148-2 [1]. 

6.2  Measurement procedure used 
Tests  were  performed  on  13/01/2023  (laboratory  temperature  19.8  ±  0.2 °C),  in  accordance  with  ISO 148-
1:2016  [2].  The  measurement  sequence  was:  SB-MB-SB-MB-SB-MB-SB-MB-SB-MB-SB.  The  measured 
absorbed energy values were corrected for friction and air resistance losses.  

6.3  Evaluation of results 

6.3.1  Technical evaluation 
The  results  of  the  MB  samples  are  within  the  range  of  acceptable  bias  allowed  for  reference  pendulums 
specified in ISO 148-3 [18] (±5 % (KVMB ≥ 40 J) or ±2 J (KVMB < 40 J). This proves that the pendulum used for 
characterisation was functioning properly.  
After testing, all Charpy test pieces show 'first-strike' marks: these are the marks caused by the interaction 
between test piece and anvils during the first and intended hammer impact. Upon fracture, the broken halve 
test pieces loose contact with hammer and anvils and follow one of a variety of possible trajectories, away 
from the pendulum, depending on the properties of both pendulum and test material. It may occur that test 
pieces show 'second-strike' marks. These are marks caused by a second impact of the already broken halves 
of the test pieces back onto the anvils. This phenomenon has been described by Schmieder et al. [23]. None 
of the broken ERM-FA016bp or of ERM-FA016ax test pieces showed second-strike marks.  
Accumulation of debris from consecutive tests can lead to a trend in the measurement sequence. The results 
of MB and SB were tested for a linear trend using regression analysis. The regression of result versus position 
in the analytical sequence was not significant on a 95 % significance level. 
The accepted data obtained on individual test pieces are shown in Figure 4 and Annex 2.  

12 

 
 
 
 
 
 
 
 
Figure 4. Absorbed energy values of 30 test pieces of ERM-FA016bp and 25 test pieces of ERM-FA016ax; data are 
displayed in the actual test sequence. 

6.4  Statistical evaluation 
The results of the measurements are summarised in Table 1. 

Table 1. Data from the characterisation measurements 

Number of 
test pieces 

nMB , nSB 

ERM-FA016ax (MB) 

ERM-FA016bp (SB) 

25 

30 

Mean value 

SBX   

MBX  , 
[J] 

124.83 

113.87 

Standard 
deviation 

sMB , sSB 
[J] 

2.91 

3.12 

Relative standard 
deviation 

RSDSB, RSDMB 
[%] 

2.33 

2.74 

The  SB-results  meet  the  ISO 148-3  [18]  acceptance  criteria  for  repeatability  for  a  batch  of  reference 
materials (sSB ≤ 2 J for KVSB < 40 J or ≤ 5 % for KVSB ≥ 40 J). 

To calculate KVCRM for ERM-FA016bp one needs KVMB of the MB used, i.e. ERM-FA016ax [3]. Table 2 shows the 
main MB-data, taken from the certification report of ERM-FA016ax [3]. 

Table 2. Data from the certification of Master Batch ERM-FA016ax [3] 

Certified absorbed 
energy of Master 
Batch, KVMB 
[J] 
126.82 

Standard 
uncertainty of KVMB 
, uMB 
[J] 
0.93 

Relative standard 
uncertainty of KVMB  , uMB,rel 

[%] 
0.73 

ERM-FA016ax 

From the data in Table 1 and Table 2, and using Equation 1, one readily obtains that KVCRM = 116 J (rounding 
in accordance with uncertainty; see Table 4). The uncertainty associated with the characterisation of the SB, 
uchar, is assessed as in Equation 3 [17], which sums the relative uncertainties of the three factors in Equation 
1: 

𝑢𝑢𝑐𝑐ℎ𝑎𝑎𝑎𝑎 = 𝐾𝐾𝐾𝐾𝐶𝐶𝐶𝐶𝐶𝐶�

2
𝑢𝑢𝑀𝑀𝑀𝑀
2
𝐾𝐾𝐾𝐾𝑀𝑀𝑀𝑀

2
𝑠𝑠𝑆𝑆𝑀𝑀
2

𝑛𝑛𝑆𝑆𝑀𝑀𝑥𝑥̅𝑆𝑆𝑀𝑀

+

+

2
𝑠𝑠𝑀𝑀𝑀𝑀
2

𝑛𝑛𝑀𝑀𝑀𝑀𝑥𝑥̅𝑀𝑀𝑀𝑀

Equation 3 

13 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
SBX  and  MBX were obtained under repeatability conditions. Therefore, the uncertainty of the ratio 
 is not 
affected  by  the  contributions  from  reproducibility  and  bias  of  the  pendulum  used  to  compare  MB  and  SB. 
Table 3 summarises the input quantities of the uchar uncertainty budget, their respective statistical properties, 
and shows how they were combined. The effective number of degrees of freedom (
eff) for uchar is obtained 
using  the  Welch-Satterthwaite  equation  from  the  combined  uncertainty  (uc)  and  the  individual  uncertainty 
contributions (ui) and their respective degrees of freedom (

i) (Equation 4) [15]. 

SB / X

ν

ν

MB

X

ν

eff

=

u
N

4
c
4
u
∑
i
= ν
1

i

i

Equation 4 

Table 3. Uncertainty budget of uchar for ERM-FA016bp  

Source 
uncertainty 

of 

Measured 
value 

Standard 
uncertainty 

Probability 
distribution 

Relative 
uncertainty 

[J] 

[J] 

KVMB 

  SBX

  MBX

Certification 
MB 

of 

126.82 

0.93 

normal 

of 
in 

Comparison 
SB  and  MB 
repeatability 
conditions 

113.87 

0.57 

normal 

124.83 

0.58 

normal 

uchar,rel [%] 

uchar [J] 

[%] 

0.73 

050 

0.47 

1.00 

1.16 

Degrees 
of 
freedom 

13 

29 

24 

38 

14 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7  Value assignment  

Box 6. Assignment of values to a reference material 

Based  on  the  outcome  of  characterisation  measurements  three 
types  of  values  can  be  assigned,  namely  certified,  indicative  or 
additional material information values. 

Certified  values  are  values  that  fulfil  the  highest  standards  of  accuracy.  Procedures  at  JRC  Directorate  F 
require a sufficient number of datasets to assign certified values. Full uncertainty budgets in accordance with 
ISO 17034 [4] and ISO Guide 35 [5] are required. Certified values of a CRM can be used for calibration and 
trueness controls.  
Indicative  values  are  values  where  either  the  uncertainty  is  deemed  too  large  or  too  few  independent 
datasets  are  available  to  allow  certification.  Indicative  values  of  an  RM  can  be  used  for  statistical  quality 
control  (homogeneity  and  stability  has  been  assessed)  but  not  for  calibration,  demonstration  of  method  or 
laboratory proficiency or method trueness.  
Additional material information values are values for which homogeneity and stability has usually not been 
assessed and insufficient data for characterisation is available. Consequently, an estimate of the reliability of 
the values is not possible and no uncertainty is given. Additional material information values cannot be used 
for calibration, demonstration of method or laboratory proficiency or method trueness. They can be used to 
e.g. anticipate possible interferences in measurement processes. 

For this CRM, a certified value was assigned. 

7.1  Certified value, combined and expanded uncertainty 
The energy value obtained from the comparison of the SB with the MB as described in 6.3 was assigned as 
certified value. 
The  uncertainty  of  the  certified  value  is  obtained  by  combining  the  contributions  from  the  characterisation 
study, uchar, and from the homogeneity assessment, uh, as is summarised in the following uncertainty budget 
(Table 4).  

The relevant number of degrees of freedom calculated using the Welch-Satterthwaite equation (Equation 4, 
ν
CRM = 58) to justify the use of a coverage factor k
= 2 to expand the confidence 
[15]), is sufficiently large (
level  to  about  95 %.  The  obtained  expanded  uncertainty  provides  justification  for  the  SB-MB  approach 
followed: UCRM is sufficiently smaller (UCRM = 2.87 % or 4 J) than the verification criterion 10 % for KV ≥40 J 
for industrial pendulums [1] or even 5 % for KV ≥40 J for reference pendulums [12].  

Table 4. Uncertainty budget of KVCRM for ERM-FA016bp 

uchar, rel 

Certified 
value 1) 
[J] 
Absorbed energy 
116 
1) Mean KV of the five test pieces 
2) Expanded (k = 2) and rounded uncertainty; uncertainties are always rounded up [24] and in a way that the 
rounding error corresponds to 3 % to 30 % of the uncertainty 

[%] 
1.43 

[%] 
2.87 

[%] 
1.00 

[%] 
1.02 

UCRM, rel 

uCRM, rel 

[J] 
4 

uh, rel 

UCRM 

2) 

15 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8  Metrological traceability and commutability 

8.1  Metrological traceability 

Box 7. Metrological traceability 

Metrological  traceability  of  measurement  results  is  a  key  requirement  for  ensuring  the  comparability  of 
data. The certified value of an RM is metrologically traceable if the measurements used for establishing it 
can be related to a reference through an unbroken chain of calibrations.  

This requires that these measurements 

• refer to the same property (e.g. Pb) and the same (kind of) quantity (e.g. Pb content),  
• result in a number and its uncertainty (e.g. 6 ± 2) expressed in the same measurement unit (e.g. µg/kg). 

The  concept  of  traceability  rests  on  several  anchor  points,  namely  identity,  quantity  value  and 
measurement unit. 

The  identity  of  a  measurand  can  be  defined  by  its  structure  alone  or  can  be  operationally  defined,  the 
quantity value of the measurand can refer to the SI, or to other appropriate references.   

Identity 
Absorbed energy KV is an operationally defined measurand, and can only be obtained by following ISO 148-
1:2016 [2], using an ISO-type striker of 2 mm tip radius at the specified test temperature.  

Quantity value 
The  certified  value  of  the  MB  ERM-FA016ax  is  traceable  to  the  SI,  since  it  was  obtained  from  an 
intercomparison of qualified laboratories, thus combining results obtained from tests in accordance with the 
ISO  148-2  [1]  and  using  instruments  verified  and  calibrated  with  SI-traceable  calibration  tools.  The 
uncertainty  contribution  from  these  individual  calibrations  all  contribute  to  the  uncertainty  of  the  certified 
value of the MB. 
The  certified  value  of  ERM-FA016bp  is  made  traceable  to  the  SI-traceable  certified  value  of  the  MB  by 
testing SB and MB test pieces under repeatability conditions on an impact pendulum verified and calibrated 
with  SI-traceably  calibrated  tools.  Therefore,  the  certified  value  of  ERM-FA016bp  is  traceable  to  the 
International  System  of  Units  (SI)  via  the  corresponding  Master  Batch  ERM-FA016ax  of  a  similar  nominal 
absorbed energy.  

16 

 
 
 
 
 
8.2  Commutability 

Box 8. Commutability 

Commutability  is  a  prerequisite  for  RMs  intended  to  be  used  for  calibration  or  quality  control  of  different 
measurement  procedures  targeting  the  same  measurand.  The  concept  of  commutability  of  a  reference 
material is defined by the VIM [25] as: 
“property of a reference material, demonstrated by the closeness of agreement between the relation among 
the measurement results for a stated quantity in this material, obtained according to two given measurement 
procedures, and the relation obtained among the measurement results for other specified materials”  

Commutability is a property of an RM indicating how well an RM mimics the 
characteristics  of  a  typical  routine  sample  in  various  measurement 
procedures for a stated measurand.  
The same RM may be commutable for some measurement procedures but 
non-commutable  for  others.  A  commutability  statement  is  therefore  only 
valid for the mentioned measurement procedure(s). 

The samples of ERM-FA016bp are made from commercially sourced alloy steel which behaves like any other 
alloy steel of the same energy level. The material is therefore commutable with other alloy steel samples. 

The certified value of this CRM is operationally defined and can only be obtained when tested in accordance 
with ISO 148-1:2016 [2]. The certified values are not  valid when the test pieces are broken with an ASTM-
type striker of 8 mm tip radius [12].  
If the CRM nevertheless is used with a different method, then the user has to assess the commutability of 
the reference material. For further guidance, see Application Note 8 [26]. 

17 

 
 
 
 
 
 
 
9 

Instructions for use 

9.1  Storage conditions 
The material should be stored at (18 ± 5) °C in the dark and dry place.  

For  more  information  regarding  the  shelf  life  of  reference  materials  please  see  ERM  Application  Note  7, 
available on https://crm.jrc.ec.europa.eu/e/132/User-support-Application-Notes . 

Note that the European Commission cannot be held responsible for changes that may happen during storage 
of the material at the customer's premises, especially of opened samples. 

9.2  Sample preparation 
Special  attention  is  drawn  to  the  cleaning  and  conditioning  of  the  test  pieces  prior  to  the  tests.  It  is 
mandatory to remove the oil from the test piece surface prior to testing, without damaging the edges of the 
test piece. Between the moment of removing the protective oil layer and the actual test, corrosion can occur. 
This must be avoided by limiting this period of time, while keeping the test piece clean. 

The following cleaning and conditioning procedure is considered to be good practice. 

1.  Use  absorbent  cleaning-tissue  and  technically  pure  ethanol  to  clean  and  degrease  each  specimen. 

Pay particular attention to the notch of the sample. 

2.  Once samples are degreased, only manipulate the samples wearing clean gloves. This is to prevent 

development of corrosion between the time of cleaning and the actual test. 

3.  Before  testing,  bring  the  specimens  to  the  test  temperature  (20  ±  2)  °C.  To  ensure  thermal 

equilibrium, move the specimens to the test laboratory at least 3 h before the tests. 

 Pendulum impact tests 

9.3 
After  cleaning  and  equilibration,  the  five  test  pieces  constituting  a  CRM  unit  need  to  be  broken  with  a 
pendulum  impact  test  machine  in  accordance  with  ISO  148-2  [1].  Prior  to  the  tests,  the  anvils  must  be 
cleaned.  It  must  be  noted  that  Charpy  test  pieces  sometimes  leave  debris  on  the  Charpy  pendulum  anvils. 
Therefore, during testing, the anvils must be checked regularly and if debris is found, it must be removed. The 
uncertainty of the certified value applies to the mean of the five KV-values. 

9.4  Use of the certified value 
Test pieces of ERM-FA016bp are ‘certified reference test pieces’ as defined in ISO 148-3 [18]. Sets of five of 
these certified reference test pieces are intended for the indirect verification of impact testing machines with 
a striker of 2 mm tip radius according to procedures described in detail in ISO 148-2 [1].  

The indirect verification provides an assessment of the bias of the user’s Charpy pendulum impact machine. 
This bias assessment can be used in the calculation of the measurement uncertainty of Charpy tests on the 
pendulum after indirect verification. Such uncertainty calculation requires the certified value, the associated 
CRM)  of  the 
uncertainty,  and  when  testing  limited  numbers  of  test  pieces,  also  the  degrees  of  freedom  (
uncertainty, all given on page 1 of the certificate. 

ν

18 

 
 
 
 
 
 
 
 
10  Conclusions 
ERM-FA016bp is a matrix material certified for absorbed energy when subjected to the Charpy impact test 
according to ISO 148-1:2016 [2] for strikers with a 2 mm tip radius. This material was produced and certified 
in accordance with ISO 17034:2016 [4] and ISO Guide 35:2017 [5]. ERM-FA016bp was produced within the 
scope of ISO 17034 accreditation. 

Test pieces of ERM-FA016bp are ‘certified reference test pieces’ as defined in ISO 148-3 [18]. Sets of five of 
these certified reference test pieces are intended for the indirect verification of impact testing machines with 
a striker of 2 mm tip radius according to procedures described in detail in ISO 148-2 [1].  

The following value was assigned: 

Table 5. Value assigned for ERM-FA016bp 

Steel Charpy V-notch test pieces 

Certified value 2) 
[J] 

Uncertainty 3) 
[J] 

Absorbed energy (KV) 1) 

116 

4 

1) Impact energy required to break a V-notched test piece of standardised dimensions, as defined in ISO 148-1:2016. The certified 
value is valid only for strikers with a 2 mm tip radius, and in the temperature range of (20 ± 2) °C. 

2)  Certified  values  are  values  that  fulfil  the  highest  standards  of  accuracy.  The  given  value  represents  the  arithmetic  mean  of  30 
individual  results  obtained  by  direct  comparison  of  ERM-FA016bp  with  ERM-FA016ax,  a  master  batch  of  similar  nominal  absorbed 
energy, under repeatability conditions on an impact pendulum verified and calibrated according to ISO 148-2:2016. The certified value 
and  its  uncertainty  refer  to  the  mean  KV  of  the  five  test  pieces  delivered  as  one  set.  The  certified  value  and  its  uncertainty  are 
traceable to the International System of Units (SI). 

3)  The  uncertainty  of  the  certified  value  is  the  expanded  uncertainty  with  a  coverage  factor  k  =  2  corresponding  to  a  level  of 
confidence of 95 %, estimated in accordance with ISO 17034:2016 and ISO Guide 35:2017. The certified uncertainty has 58 effective 
degrees of freedom. 

19 

 
 
 
 
 
 
 
 
References   

1  

2  

ISO  148-2:2016,  Metallic  materials  -  Charpy  pendulum  impact  test  -  Part  2:  Verification  of  testing 
machines, International Organization for Standardization, Geneva, Switzerland 
ISO 148-1:2016, Metallic materials - Charpy pendulum impact test - Part 1: Test method, International 
Organization for Standardization, Geneva, Switzerland 

5  

4  

3   Roebben,  G,  Dean,  A,  Lamberty,  A,  Certification  of  Master  Batches  of  Charpy  V-notch  reference  test 
pieces of nominal energy levels 30 J,  80 J and  120 J -  Certified Reference  Materials ERM®-FA013ba, 
ERM®-FA015v  and  ERM®-FA016ax,  EUR  23760  EN,  Office  for  Official  Publications  of  the  European 
Communities, Luxembourg, 2009 ISBN 978-92-79-11327-7; available from https://op.europa.eu/ 
ISO  17034:2016,  General  requirements  for  the  competence  of  reference  material  producers, 
International Organization for Standardization, Geneva, Switzerland 
ISO  Guide  35:2017,  Reference  materials  –  Guidance  for  characterization  and  assessment  of 
homogeneity and stability, International Organization for Standardization, Geneva, Switzerland 
EN 1992 1 to -4, Eurocode 2: Design of concrete structures, European Committee for Standardization, 
Brussels, 2004 
EN  1993-1  to  -6,  Eurocode  3,  Design  of  steel  structures,  European  Committee  for  Standardization, 
Brussels, 2004 
EN 1994-1 to -2, Eurocode 4: Design of composite steel and concrete structures, European Committee 
for Standardization, Brussels, 2004 

6  

8  

7  

9   Directive 2014/24/EU of the European Parliament and the Council on public procurement and repealing 

Directive, 26. February 2014 

10   Regulation 305/2011 of the European Parliament and of the Council laying down harmonised conditions 

for the marketing of construction products 9 March 2011  

11   Directive 2014/68/EU of the European Parliament and the Council on the harmonisation of the laws of 
the Member States relating to the making available on the market of pressure equipment, 15 May 2014 
12   ASTM  E23  –  18,  Standard  Test  Methods  for  Notched  Bar  Impact  Testing  of  Metallic  Materials,  ASTM 

International, West Conshohocken, PA, United States of America 

13   H.  Marchandise,  A.  Perez-Sainz,  W.  Colinet,  Certification  of  the  impact  toughness  of  V-notch  Charpy 

specimens, in BCR information series, Community Bureau of Reference - BCR, Brussels, Belgium, 1991 

14   R.K. Varma, The certification of two new master batches of V-notch Charpy impact toughness specimens 
in  accordance  with  EN  10045-2:  1992,  CRM's  015  and  415,  EUR  Report  18947  EN  -  European 
Communities, Luxembourg - 1999 - ISBN 92-828-2244-3 

15   ISO/IEC Guide 98-3:2008, Uncertainty of measurement - Part 3: Guide to the expression of uncertainty 
in measurement (GUM:1995), International Organization for Standardization, Geneva, Switzerland 
16   C. Ingelbrecht, J. Pauwels, EC Reference Materials for Impact Toughness - Traceability and uncertainty. 
Presentation  at  Eurachem  Eurolab  symposium  on  Reference  Materials  for  Technologies  in  the  New 
Millennium, Berlin, Germany, May 22-23, 2000 

17   C.  Ingelbrecht,  J.  Pauwels,  and  Gyppaz,  D.,  Charpy  specimens  from  BCR  for  machine  verification 
according to EN 10045-2. Poster presentation at Charpy Centenary Conference, Poitiers, France, October 
2-5, 2001 

18   ISO  148-3:2016,  Metallic  materials  -  Charpy  pendulum  impact  test  -  Part  3:  Preparation  and 
characterization  of  Charpy  V-notch  test  pieces  for  indirect  verification  of  pendulum  impact  machines, 
International Organization for Standardization, Geneva Switzerland 

19   Production report: Charpy V-notch reference test pieces  120 J nominal absorbed energy ERM-FA016bp, 

Institut für Eignungsprüfung GmbH, Marl (DE), 17 May 2019 

20   J. Pauwels, D. Gyppaz, R. Varma, C.  Ingelbrecht, European certification of Charpy  specimens: reasoning 

and observations, ASTM Special Technical Publication 1380 (199) 90-99 

21   C.N. McCowan, G. Roebben, Y. Yamaguchi, S. Lefrançois, J.D. Splett, S. Takagi, A. Lamberty, International 

Comparison of Impact Reference Materials (2004), J. ASTM International, Vol. 3(2), 2004 

22   A.  Lamberty,  G.  Roebben,  A.  Dean,  T  Linsinger  Study  of  the  stability  of  Charpy  V-notch  reference  test 
pieces for tests at 20 °C (ERM-FA013ba, ERM-FA015v and ERM-FA016ax) during long-term storage at 
18°C, EUR 26348 EN, Luxembourg: Publications Office of the European Union, 2015 

23   A.K.  Schmieder,  P.T  Purtscher,  D.P.  Vigliotti,  The  role  of  strike  marks  on  the  reproducibility  of  Charpy 
impact test results, in Pendulum impact machines: procedures and specimens for verification, ASTM STP 

20 

 
 
 
 
1248,  ed.  Siewert,  T.A.  and  Schmieder  A.K.,  American  Society  for  Testing  and  Materials,  Philadelphia, 
United States of America, 1995 

24   DIN 1333:1992-02, Zahlenangaben, Deutsches Institut für Normung e.V., Berlin, Germany 
25   ISO/IEC  Guide  99:2007,  International  vocabulary  of  metrology  –  Basic  and  general  concepts  and 

associated terms (VIM), International Organization for Standardization, Geneva, Switzerland 

26   L.  Deprez,  ERM  Application  Note  8:  Assessing 

commutability  of 

reference  materials, 

https://crm.jrc.ec.europa.eu/e/132/User-support-Application-Notes (last accessed on 23.1.2023) 

21 

 
                                                                                                                                                                            
List of abbreviations  

AISI 
ASTM  
BCR 
BELAC 
CRM 
EC 
EU 
ERM® 
IEC 
IMB 
IfEP 
ISO 
JRC 
k 
KV 

KVCRM 
KVMB 
LNE 
MB 
nMB 

nSB  
RM 
RMP 
RSD 
RSDMB 

RSDSB 

s 
SB 
sh 

sMB  

SI 
sSB 

uCRM 
UCRM 

uchar 

uh 

ui 
uMB 
MBX

SBX

∆

h 

ν
i 
ν
CRM 

American Iron and Steel Institute 
ASTM International (American standardisation organisation) 
Community Bureau of Reference 
Belgian accreditation body 
Certified Reference Material 
European Commission 
European Union 
Trademark owned by the European Commission; used by the JRC for reference materials 
International Electrotechnical Commission 
International Master Batch 
Institut für Eignungsprüfung GmbH 
International Organization for Standardization 
Joint Research Centre of the European Commission 
Coverage factor 
Absorbed energy  = energy required to break a  V-notched  test piece of defined shape  and 
dimensions when tested with a pendulum impact testing machine 
Certified KV value of a set of five reference test pieces from the Secondary Batch 
Certified KV value of the Master Batch test pieces 
Laboratoire National de Métrologie et D’Essais 
Master Batch 
Number  of  test  pieces  of  the  Master  Batch  tested  during  certification  of  the  Secondary 
Batch 
Number of test pieces of the Secondary Batch tested for certification  
Reference Material 
Reference Material Producer 
Relative standard deviation 
Relative standard deviation of the nMB results of the test pieces of the Master Batch tested 
for the certification of the Secondary Batch 
Relative standard deviation of the nSB results of the test pieces for the characterisation of 
the Secondary Batch 
Standard deviation 
Secondary Batch 
Standard deviation of the results of the test pieces tested to assess the homogeneity of the 
Secondary Batch  
Standard deviation of the nMB results of the test pieces of the Master Batch tested for the 
certification of the Secondary Batch  
International System of Units 
Standard deviation of the nSB results of the test pieces tested for the characterisation of the 
Secondary Batch  
Combined standard uncertainty of the certified value 
Expanded  uncertainty  of  the  certified  value  ;  an  additional  index  "rel"  is  added  when 
appropriate 
Standard  uncertainty  of  the  material  characterisation;  an  additional  index  "rel"  is  added 
when appropriate 
Standard uncertainty related to a possible between-unit inhomogeneity; an additional index 
"rel" is added when appropriate 
Value of uncertainty from contribution i 
Standard uncertainty of KVMB; an additional index "rel" is added when appropriate 
Mean KV  value of the nMB measurements on test pieces  of the  Master Batch tested  when 
characterising the Secondary Batch  
Mean  KV  value  of  the  nSB  results  of  the  test  pieces  tested  for  the  characterisation  of  the 
Secondary Batch  
difference between the height of the centre of gravity of the pendulum prior to release and 
at the end of the half-swing during which the test piece is broken 
Degrees of freedom for uncertainty component i 
Effective degrees of freedom of the uncertainty of the certified value 

22 

 
 
 
23 

 
 
 
List of boxes 
Box 1. Reference material production ..................................................................................................................................................... 6 
Box 2. Reference material processing ..................................................................................................................................................... 8 
Box 3. Homogeneity assessment ................................................................................................................................................................ 10 
Box 4. Stability assessment ........................................................................................................................................................................... 11 
Box 5. Reference material characterisation ......................................................................................................................................... 12 
Box 6. Assignment of values to a reference material ................................................................................................................... 15 
Box 7. Metrological traceability ................................................................................................................................................................... 16 
Box 8. Commutability ......................................................................................................................................................................................... 17 

24 

 
 
 
List of figures 
Figure 1. Relation between EU legislation and the availability of Charpy CRMs. .................................................................... 3 
Figure 2. Schematic presentation of the Charpy pendulum impact test. ..................................................................................... 4 
Figure 3. Schematic drawing of a V-notched Charpy test piece........................................................................................................ 4 
Figure 4. Absorbed energy values of 30 test pieces of ERM-FA016bp and 25 test pieces of ERM-FA016ax .. 13 

25 

 
 
 
 
List of tables 
Table 1: Data from the characterisation measurements .................................................................................................................... 13 
Table 2: Data from the certification of Master Batch ERM-FA016ax [3] .................................................................................. 13 
Table 3: Uncertainty budget of uchar for ERM-FA016bp ........................................................................................................................ 14 
Table 4: Uncertainty budget of KVCRM for ERM-FA016bp ..................................................................................................................... 15 
Table 5: Value assigned for ERM-FA016bp ................................................................................................................................................. 19 

26 

 
 
Annexes 

Annex 1. Results of tests for the homogeneity assessment  

Figure 1.1 Results of tests for the homogeneity assessment of ERM-FA016bp. 

27 

 
 
 
 
 
Annex 2. Results of characterisation measurements  

Table  2.1  Data  for  ERM-FA016bp  and  ERM-FA016ax  as  measured  according  to  ISO 148-1  [2]  at  LNE 
13/01/2023. 
Result number 

1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
28 
29 
30 
Mean [J] 

Standard deviation [J] 
RSD [%] 

Master Batch ERM-FA016ax 
KV [J] 
128.15 
126.43 
122.09 
123.99 
123.86 
129.00 
127.69 
124.61 
117.67 
122.04 
126.18 
125.16 
125.99 
126.20 
130.33 
125.21 
124.06 
125.53 
123.14 
122.36 
128.54 
120.73 
123.30 
127.16 
121.37 

Secondary Batch ERM-FA016bp 
KV [J] 
113.47 
112.62 
120.06 
110.25 
111.75 
110.76 
114.57 
116.36 
116.64 
116.20 
114.80 
120.22 
113.03 
109.06 
112.89 
112.18 
113.47 
109.01 
116.62 
110.92 
114.55 
117.88 
115.42 
115.38 
112.55 
116.98 
108.05 
113.70 
116.36 
110.30 

124.83 
2.91 
2.33 

113.87 
3.12 
2.74% 

28 

 
 
 
 
 
 
 
 
 
 
 
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