SIST EN ISO 20623:2018

SLOVENSKI STANDARD
SIST EN ISO 20623:2018
01-april-2018
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SIST EN ISO 20623:2004
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Petroleum and related products - Determination of the extreme-pressure and anti-wear
properties of fluids - Four ball method (European conditions) (ISO 20623:2017)
Mineralölerzeugnisse und verwandte Produkte - Bestimmung der EP-Eigenschaften und
Verschleißkennwerte von Schmierstoffen - Verfahren mit dem Vierkugel-Apparat
(Europäische Bedingungen) (ISO 20623:2017)
Pétrole et produits connexes - Détermination des propriétés extrême pression et anti-
usure des fluides - Essai quatre billes (conditions européennes) (ISO 20623:2017)
Ta slovenski standard je istoveten z: EN ISO 20623:2018
ICS:
75.100 Maziva Lubricants, industrial oils and
related products
SIST EN ISO 20623:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 20623:2018

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SIST EN ISO 20623:2018


EN ISO 20623
EUROPEAN STANDARD

NORME EUROPÉENNE

January 2018
EUROPÄISCHE NORM
ICS 75.100 Supersedes EN ISO 20623:2003
English Version

Petroleum and related products - Determination of the
extreme-pressure and anti-wear properties of lubricants -
Four-ball method (European conditions) (ISO
20623:2017)
Pétrole et produits connexes - Détermination des Mineralölerzeugnisse und verwandte Produkte -
propriétés extrême pression et anti-usure des Bestimmung der EP-Eigenschaften und
lubrifiants - Essai quatre billes (conditions Verschleißkennwerte von Schmierstoffen - Verfahren
Européennes) (ISO 20623:2017) mit dem Vierkugel-Apparat (Europäische
Bedingungen) (ISO 20623:2017)
This European Standard was approved by CEN on 6 December 2017.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 20623:2018 E
worldwide for CEN national Members.

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SIST EN ISO 20623:2018
EN ISO 20623:2018 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 20623:2018
EN ISO 20623:2018 (E)
European foreword
This document (EN ISO 20623:2018) has been prepared by Technical Committee ISO/TC 28 "Petroleum
and related products, fuels and lubricants from natural or synthetic sources" in collaboration with
Technical Committee CEN/TC 19 “Gaseous and liquid fuels, lubricants and related products of
petroleum, synthetic and biological origin” the secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by July 2018, and conflicting national standards shall be
withdrawn at the latest by July 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 20623:2003.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 20623:2017 has been approved by CEN as EN ISO 20623:2018 without any modification.

3

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SIST EN ISO 20623:2018

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SIST EN ISO 20623:2018
INTERNATIONAL ISO
STANDARD 20623
Second edition
2017-12
Petroleum and related products —
Determination of the extreme-
pressure and anti-wear properties
of lubricants — Four-ball method
(European conditions)
Pétrole et produits connexes — Détermination des propriétés extrême
pression et anti-usure des lubrifiants — Essai quatre billes (conditions
Européennes)
Reference number
ISO 20623:2017(E)
©
ISO 2017

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SIST EN ISO 20623:2018
ISO 20623:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

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SIST EN ISO 20623:2018
ISO 20623:2017(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Cleaning solvents . 2
6 Apparatus . 3
7 Samples and sampling . 5
8 Preparation of apparatus . 5
9 General procedure . 5
10 Test procedures . 7
10.1 Test A — Load-Wear Index (LWI) . 7
10.2 Test B — Wear-load curve, welding load, and initial seizure load . 7
10.3 Test C — Wear test . 8
11 Calculations. 9
11.1 General . 9
11.2 Test A — Load wear index. 9
11.3 Test B — Wear-load curve, initial seizure load .10
11.4 Test C — Wear test .10
12 Expression of results .11
13 Precision .11
13.1 General .11
13.2 Repeatability .11
13.3 Reproducibility .11
14 Test report .11
Annex A (normative) Test ball specifications .13
Annex B (normative) Mean Hertz Load data sheet .14
Bibliography .16
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SIST EN ISO 20623:2018
ISO 20623:2017(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the 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 the following
URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 28, Petroleum and related products, fuels
and lubricants from natural or synthetic sources.
This second edition cancels and replaces the first edition (ISO 20623:2003), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— this document has been extended to all types of liquid lubricants and greases, whereas previously
it applied only to fire-resistant hydraulic fluids;
— the procedures have been technically revised but the essentials remain the same;
— the test balls have been better specified (see Annex A) and calculations for the wear test have been
included;
— the calibration procedure of the friction recorder springs has been deleted and reference is now
made to the manufacturer's instructions.
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SIST EN ISO 20623:2018
ISO 20623:2017(E)

Introduction
The four-ball machine is widespread and commonly used to assess the anti-wear properties of all types
of liquid lubricants, lubricating greases and other consistent lubricants.
An electrical motor, the rotational speed of which depends on the frequency of the current, actuates
the four-ball machine. So, depending on the country where the machines are used, the results obtained
cannot be compared.
ASTM has standardized several procedures with these methods, based on the use of the four-ball
machine:
— ASTM D2266;
— ASTM D4172;
— ASTM D2596;
— ASTM D2783.
The Energy Institute has standardized IP 239.
DIN has standardized DIN 51350, divided into five parts:
— Part 1: General working principles;
— Part 2: Determination of the welding load of liquid lubricants;
— Part 3: Determination of the wearing characteristics of liquid lubricants;
— Part 4: Determination of the welding load of consistent lubricants;
— Part 5: Determination of the wearing characteristics of consistent lubricants.
DIN, ASTM and Energy Institute test methods stipulate different rotational speeds.
Table 1 summarizes the test conditions for the above standards.
Table 1 — Test conditions of the various four-ball standards
Rotational
Type Temperature
Standard Lubricant Load (N) Duration speed
of test °C
r/min
ASTM D2266 Grease Wear 392 60 min 1 200 75
147 (A) 75
ASTM D4172 Oil Wear 60 min 1 200
392 (B) 75
Extreme
ASTM D2596 Grease 59 to 7 848 10 s 1 770 19 to 35
pressure
Extreme
ASTM D2783 Oil 59 to 7 848 10 s 1 760 18 to 35
pressure
Extreme
Wear: 60 min
IP 239 Grease — oil pressure 60 to 7 940 1 450 Not specified
EP: 10 s or 60 s
+ wear
2 000 to
DIN 51350-2 Oil Weld load 60 s 1 450 18 to 40
12 000
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Table 1 (continued)
Rotational
Type Temperature
Standard Lubricant Load (N) Duration speed
of test °C
r/min
150 (A)
DIN 51350-3 Oil Wear 60 min 1 450 18 to 40
300 (B)
Consistent 2 000 to
DIN 51350-4 Weld load 60 s 1 450 18 to 40
lubricant 12 000
150 (C) 60 min
Consistent
DIN 51350-5 Wear 300 (D) 60 min 1 450 18 to 40
lubricant
1 000 (E) 60 s
The lubricants' properties defined by the various test methods are also different. They are defined in
Table 2.
Table 2 — Lubricant properties evaluation by the different methods
Standard Lubricant property
ASTM D2262 MWSD (mm) under 392 N load
ASTM D4172 MWSD (mm) under 147 N of 392 N
ASTM D2596 WL (N), LWI (N), LNSL (last non-seizure load) (N)
ASTM D2783 WL (N), LWI (N)
IP 239 WL (N), LWI (10 s or 60 s), ISL (N), MWSD (mm) (10 s, 60 s or 60 min)
DIN 51350-2 WL (N)
DIN 51350-3 MWSD (150 N or 300 N, 60 min)
DIN 51350-4 WL (N)
DIN 51350-5 MWSD (150 N, 300 N or 1 000 N)
The purpose of this document is to propose a single standard to evaluate the extreme-pressure and
the anti-wear properties of all types of lubricants, with the 4-ball machine, based on a single rotational
speed of 1 450 r/min.
The operating procedures take into account all the features present on the machines available on
the market.
The lubricants' properties involved are as follows:
a) initial seizure load (ISL);
b) weld load (WL);
c) wear-load curve;
d) Load-Wear Index (LWI);
e) anti-wear characteristics short duration (MWSD) (10 s or 60 s) and long duration (60 min).
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SIST EN ISO 20623:2018
INTERNATIONAL STANDARD ISO 20623:2017(E)
Petroleum and related products — Determination of the
extreme-pressure and anti-wear properties of lubricants
— Four-ball method (European conditions)
WARNING — The use of this document can involve hazardous materials, operations and
equipment. This document does not purport to address all of the safety problems, if any,
associated with its use. It is the responsibility of users of this document to take appropriate
measures to ensure the safety and health of personnel prior to the application of this document,
and to determine the applicability of any other restrictions.
1 Scope
This document specifies procedures for the measurement of the extreme pressure (EP) and anti-
wear properties of liquid lubricants (categories C, D, F, G, H, M, P of ISO 6743-99), lubricating greases
(ISO 6743-9, category X) and other consistent lubricants. The test conditions are not intended to
simulate particular service conditions, but to provide information over a range of standard conditions
for the purpose of research, development, quality control and fluid ranking. The output is used in
lubricant specifications.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3290-1, Rolling bearings — Balls — Part 1: Steel balls
ISO 3170, Petroleum liquids — Manual sampling
ASTM D4057, Standard Practice for Manual Sampling of Petroleum and Petroleum Products
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological 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/
3.1
wear
removal of metal from the test pieces
Note 1 to entry: Under conditions of low load and low friction, wear causes only small circular scars on the three
stationary balls and a ring on the rotating ball. The diameters of these scars are slightly larger than the diameter
of the indentation due to the static load (Hertz diameter).
3.2
seizure
localized fusion of metal between the rubbing surfaces of the test pieces
Note 1 to entry: Seizure is indicated by an increase in friction and wear, and results in roughened scars and a ring
on the balls.
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ISO 20623:2017(E)

3.3
weld
fusion of metal between the rubbing surfaces sufficient for metal to merge and the
balls to weld together in the form of a pyramid
3.4
Load-Wear Index
LWI
index of the ability of a lubricant to minimize wear (3.1) at applied load (load-
carrying property of a lubricant)
Note 1 to entry: The LWI is expressed in newtons.
3.5
wear-load curve
logarithmic plot of the load against the mean wear scar diameter (3.7)
3.6
initial seizure load
ISL
lowest load at which seizure (3.2) occurs
3.7
mean wear scar diameter
MWSD
mean of six wear scar diameter measurements, two from each of the stationary
balls, taken in the direction of rubbing of the balls and at right angles to this
4 Principle
A single ball is rotated in contact with three fixed balls, with the lubricant under test being used to
lubricate the balls. A lever enables loads to be applied and resulting measurements of wear, friction and
weld are obtained.
Depending on the result to be reported, this document specifies three different test conditions as
follows:
a) Test A for the Load-Wear Index (LWI); see 10.1;
b) Test B for the wear-load curve; see 10.2;
c) Test C for the wear; see 10.3.
5 Cleaning solvents
In order to ensure thorough cleaning, suitable solvents shall be used (it can be necessary to use
multiple cleaning steps). The best-suited solvent can depend to a significant extent on the type of
material being tested.
NOTE As an example, light hydrocarbons or acetone are acceptable choices; whereas, for some hydraulic
fluids, an alcohol with low molecular mass can assist in the first cleaning step.
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SIST EN ISO 20623:2018
ISO 20623:2017(E)

6 Apparatus
6.1 Four-ball extreme-pressure lubricant testing machine, consisting of a device by means of
which a bearing ball is rotated in contact with three fixed bearing balls immersed in the fluid under test.
A sectional view is illustrated in Figure 1. Loads are applied to the balls by means of various possible
devices like discs on a load lever, electrical jacks, hydraulic or pneumatic devices. The upper rotating ball
is held in a special ball clamp (see Figure 2) at the lower end of the vertical spindle of an electrical motor.
−1 −1
The driving motor should be capable of maintaining a rotational speed of 1 450 min to 1 500 min .
The lower fixed balls are held against each other in a steel cup by means of a clamping ring and locking
nut. The cup assembly is supported above the loading device by a disc that rests on a thrust bearing,
thus allowing horizontal displacement and automatic alignment of the three lower balls against the
upper ball. The frictional torque exerted on the three lower balls may be optionally measured by means
of devices that are specific to the various four-ball machine manufacturers (see 6.2).
NOTE It is important to distinguish between the four-ball extreme-pressure lubricant testing machine
specified in this document, and the four-ball wear tester that is limited to loads of 500 N or less.
6.2 Friction recording device, optional, capable of monitoring the friction behaviour of the four-
ball system during test. It shall be calibrated according to the recommendations given in the individual
manufacturer's manual.
6.3 Load masses, consisting of a series of masses designed for the application of loads from 60 N to
8 kN, for those machines operating with disks loading systems.
NOTE Some robust machines can support loads up to 12 kN.
For machines equipped with a load lever arm, the masses consist of a set of rings of different values
which locate into notches or holes machined into the lever arm. The notches or holes are identified with
the resultant force that is applied if the mass is located at a particular position
6.4 Microscope, equipped with a calibrated measuring scale capable of measuring with an accuracy
of ±0,01 mm.
6.5 Timer, manual or electronic, capable of reading to the nearest 0,2 s.
NOTE Some machines are equipped with precise timers, automatically stopping the motor when the selected
test duration is reached.
6.6 Test balls, see Annex A.
6.7 Assembly device, consisting of a suitable device bolted firmly to a bench to facilitate the assembly
and removal of the lower balls in the ball cup. The ball cup shall be fixed in such way as to enable the
locking nut to be tightened or loosened without the cup turning.
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SIST EN ISO 20623:2018
ISO 20623:2017(E)

Dimensions in millimetres
Key
1 ball clamp holder 8 brass disks
2 ball clamp 9 rubber disc
3 ball clamp fixing device 10 step bearing
4 ball cup assembly 11 weight beam with counter weight
5 ball cup mounting disk 12 fulcrum
6 thrust bearing 13 step bearing
7 pressure ram 14 pressure pin
NOTE  In some equipment, electrical, pneumatic or hydraulic devices, applying the load on the pressure ram, can
replace the weight beam.
Figure 1 — Illustrative sectional view of the four-ball EP testing machine
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SIST EN ISO 20623:2018
ISO 20623:2017(E)

Key
1 external dimensions to suit the machine
2 ground and lapped to provide a tight fit for test ball
NOTE  Material is tool steel (EN 10027).
Figure 2 — Upper ball clamp
7 Samples and sampling
Unless otherwise specified, liquid samples shall be taken in accordance with ISO 3170.
Greases shall be sampled in accordance with ASTM D4057.
8 Preparation of apparatus
8.1 Before starting a series of tests, run the machine (6.1) without load for a minimum of 15 min. Clean
all appropriate parts of the machine with the cleaning solvent (Clause 5) and dry in a stream of dry air, or
with a clean, dry, lint-free cloth.
8.2 Clean four new test balls (6.6) for each run with the cleaning solvent and dry with a clean, dry, lint-
free cloth.
9 General procedure
9.1 Place the ball cup on the assembly device (6.7). Put three clean balls into the cup, hold them in
position with the clamping ring, and secure the assembly by tightening the locknut to a torque of
68 Nm ± 7 Nm. Introduce sufficient liquid sample (8 ml to 10 ml) to cover the fixed balls to a depth of at
least 3 mm. When testing solid to semi-solid dispersions (grease), completely fill the cup, avoiding the
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SIST EN ISO 20623:2018
ISO 20623:2017(E)

inclusion of air pockets. Imbed the three test balls in the grease. Place the clamping ring, screw down the
lock nut and scrape off the excess of grease pushed onto the lock nut.
NOTE 1 Use four new balls and a fresh test portion for each run.
NOTE 2 An alternative method to apply the torque is to fasten the screw nut by hand, and then a further 60°
using a wrench.
9.2 Fit a clean ball into the upper ball clamping device and check that it cannot be rotated by hand
within the clamping device. Reject clamping devices in which the ball is loose. Fit the clamping device
into the taper at the end of the motor spindle.
9.3 Mount the ball cup assembly centrally under the spindle in contact with the fourth ball. Place the
mounting disc between the thrust bearing and the cup so that, when the cup is lowered into position, it
sits squarely on the disc and is free to rotate with it.
9.4 For machines equipped with a load lever arm, the masses consist of a set of rings of different values
which locate into notches or holes machined into the lever arm. The notches or holes are identified with
the resultant force that is applied if the mass is located in a part
...