ISO 26422:2011

INTERNATIONAL ISO
STANDARD 26422
First edition
2011-03-15

Petroleum and related products —
Determination of shear stability of
lubricating oils containing polymers —
Method using a tapered roller bearing
Pétrole et produits connexes — Détermination de la stabilité au
cisaillement des huiles lubrifiantes contenant des polymères —
Méthode avec roulement à rouleaux coniques




Reference number
ISO 26422:2011(E)
©
ISO 2011

---------------------- Page: 1 ----------------------
ISO 26422:2011(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.


COPYRIGHT PROTECTED DOCUMENT


©  ISO 2011
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland

ii © ISO 2011 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 26422:2011(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 26422 was prepared by Technical Committee ISO/TC 28, Petroleum products and lubricants.
ISO 26422 is based on DIN 51350-6, which has also been adopted by the Coordinating European Council
(CEC) as CEC-L-45-99.

© ISO 2011 – All rights reserved iii

---------------------- Page: 3 ----------------------
INTERNATIONAL STANDARD ISO 26422:2011(E)

Petroleum and related products — Determination of shear
stability of lubricating oils containing polymers — Method
using a tapered roller bearing
WARNING — The use of this International Standard may involve hazardous materials, operations and
equipment. This International Standard does not purport to address all of the safety problems
associated with its use. It is the responsibility of the user of this International Standard to establish
appropriate safety and health practices and to determine the applicability of regulatory limitations
prior to use.
1 Scope
This International Standard specifies a method of determining the shear stability of polymer-containing
lubricating oils, including pressure fluids, by the four-ball tester as specified in ISO 20623, but using a tapered
roller bearing. The test results allow prediction of the in-service permanent viscosity loss.
NOTE Other International Standards exist which evaluate viscosity loss of polymer-containing oils. The method
specified in this International Standard subjects fluids to a higher shear rate than, for example, the diesel injector nozzle
shear test in ISO 20844. It is particularly appropriate for lubricants being used in high shear applications, such as
components with gears and roller bearings. In such applications, the shear rate in the ISO 20844 test method can be too
low to generate a realistic permanent shear of the fluid.
2 Normative references
The following referenced documents are indispensable for the application 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 355, Rolling bearings — Tapered roller bearings — Boundary dimensions and series designations
ISO 3104, Petroleum products — Transparent and opaque liquids — Determination of kinematic viscosity and
calculation of dynamic viscosity
ISO 20623, Petroleum and related products — Determination of the extreme-pressure and anti-wear
properties of fluids — Four ball method (European conditions)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
percentage viscosity loss
R
V
measure of shear stability calculated in accordance with the following equation:
νν−
01
R=× 100
V
ν
0
© ISO 2011 – All rights reserved 1

---------------------- Page: 4 ----------------------
ISO 26422:2011(E)
where
2
ν is the kinematic viscosity at 100 °C of the unsheared oil, expressed in mm /s;
0
2
ν is the kinematic viscosity at 100 °C of the sheared oil, expressed in mm /s
1
NOTE 1 A small value indicates a high shear stability.
NOTE 2 The tapered roller bearing test is also known in the industry as the KRL (Kegelrollenlager) principle.
4 Principle
Using the splash lubrication method, a volume of 40 ml of the lubricating oil is tested at a constant
temperature of 60° C in a tapered roller bearing driven by the four-ball tester. The test is carried out at
constant speed and the load applied during a given running time is 5 000 N. The kinematic viscosity of the
lubricating oil is determined at a temperature of 100° C before and after the test. The percentage viscosity loss,
R , is calculated from these two viscosities.
V
NOTE Other temperatures to determine shear loss, such as 40° C, can be requested by some classification systems.
5 Reagents and materials
5.1 Cleaning solvents, appropriate to the material last tested. For mineral oils, light hydrocarbons and
acetone are suitable. For some hydraulic fluids, a low molecular mass alcohol will assist in the first cleaning
stage.
6 Apparatus
6.1 Four-ball tester, as specified in ISO 20623.
6.2 Tapered roller bearing, metric series 32008 X, in accordance with ISO 355. The single row tapered
roller bearing assembly consists of an inner race with cage and roller assembly and an outer race.
NOTE 1 It is advisable that the inner and outer races be considered to be a matched pair when obtained from the
supplier and these components not be interchanged with those of other sets of bearings.
NOTE 2 Precision has only been evaluated on SKF 32008 X/Q bearings (Q for optimized contact geometry and
bearing surfaces).
NOTE 3 The adapter shown in Figure 1 is available from several producers. It is advisable only to use adapters that
have been proven in tests run in accordance with CEC-L-45-99.
1)
6.3 Shear stability testing apparatus , as shown in Figure 1.
6.4 Temperature control device, for controlling the temperature of the oil to a temperature of 60 °C ± 1 °C,
using a temperature measuring device located in the shear stability test apparatus.
6.5 Viscometer, an appropriate glass capillary viscometer meeting the requirements of ISO 3105 or a
suitable automated viscosimeter should be used for the determination of kinematic viscosity in accordance
with ISO 3104.

1) Information on suitable products available commercially can be obtained from DIN-Bezugsquellen für normgerechte
Erzeugnisse im DIN Deutsches Institut für Normung e.V., Burggrafenstraße 6, D-10787 Berlin, Germany. This information
is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of
these products.
2 © ISO 2011 – All rights reserved

---------------------- Pag
...