ISO 8838:2024
(Main)Plain bearings — Water-lubricated plain bearing materials
Plain bearings — Water-lubricated plain bearing materials
This document specifies requirements for the selection and use of water-lubricated plain bearing materials used in different equipment and plants under various lubrication conditions, such as — fluid-film lubrication condition, — mixed lubrication condition, and — condition comprising a non-lubrication condition which shifts to a fluid-film lubrication condition. In addition, this document also specifies requirements for mating (shaft) material, the lubrication method and for items to consider during the design of water-lubricated plain bearing materials. The water used as a lubricant is pure water, tap water, river water or seawater. This document does not apply to the water solution of chemicals, refrigerants, liquid fuels, etc.
Paliers lisses — Matériaux de paliers lisses lubrifiés à l'eau
General Information
Standards Content (Sample)
International
Standard
ISO 8838
First edition
Plain bearings — Water-lubricated
2024-09
plain bearing materials
Paliers lisses — Matériaux de paliers lisses lubrifiés à l'eau
Reference number
© ISO 2024
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Published in Switzerland
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Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Plain bearing materials and mating (shafts) materials . 2
4.1 Bearing materials . .2
4.1.1 General .2
4.1.2 Wood-based material .2
4.1.3 Carbon-based material .2
4.1.4 Rubber-based material .2
4.1.5 Thermosetting resin-based material .2
4.1.6 Fluoro resin-based material .3
4.1.7 Thermoplastic resin-based material .3
4.1.8 Ceramic-based material .3
4.1.9 Cermet-based material .3
4.2 Mating (shaft) materials.3
4.2.1 General .3
4.2.2 Copper alloy .3
4.2.3 Stainless steel .3
4.2.4 Plating .3
4.2.5 Ceramics .4
4.2.6 Cermet.4
5 Characteristics, applications, manufacturing method and compatible combinations . 4
6 Water supply method . 4
6.1 General .4
6.2 Forced water supply .4
6.3 Circulating water supply .4
6.4 Immersed in water .4
7 Design considerations . 5
7.1 General .5
7.2 Water temperature .5
7.3 Removal of foreign matters .5
7.3.1 General .5
7.3.2 Methods of removing foreign matters .5
7.4 Operating conditions .6
Annex A (informative) Characteristics, applications, manufacturing methods and compatible
combinations . 7
Annex B (informative) Precautions on sources of lubricating water .13
Bibliography . 14
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
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This document was prepared by Technical Committee ISO/TC 123, Plain bearings, Subcommittee SC 7, Special
types of plain bearings.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
Water-lubricated bearings are widely used in fields such as submersible pumps, marine stern tubes,
hydroelectric generator turbines, water treatment equipment, water valves and rolling equipment for
steelmaking.
Water-lubricated plain bearings are used for the following conditions or reasons:
a) oil or greases cannot be used due to equipment usage conditions;
b) there is plenty of water available as a lubricant around the equipment;
c) even if water for lubrication leaks, it does not pollute the environment like oil or grease.
However, when using water as a lubricant, it is necessary to take the following into account:
— water freezes at 0 °C or below and becomes vapor at 100 °C or above, at normal pressure, therefore losing
load carrying capacity;
— water has low viscosity in comparison with oil;
— water cannot support a high load because the increase in viscosity that occurs in oil lubrication
(elastohydrodynamic lubrication: EHL) when it is under high pressure cannot be expected in water.
— water does not have the ability that oil and grease have to prevent corrosion on shafts and bearings.
While water-lubricated plain bearings have been used in various fields around the world and the water
that is used as a lubricant has its own specific features differing from oil, there have been no International
Standards that apply to water-lubricated plain bearings thus far.
v
International Standard ISO 8838:2024(en)
Plain bearings — Water-lubricated plain bearing materials
1 Scope
This document specifies requirements for the selection and use of water-lubricated plain bearing materials
used in different equipment and plants under various lubrication conditions, such as
— fluid-film lubrication condition,
— mixed lubrication condition, and
— condition comprising a non-lubrication condition which shifts to a fluid-film lubrication condition.
In addition, this document also specifies requirements for mating (shaft) material, the lubrication method
and for items to consider during the design of water-lubricated plain bearing materials.
The water used as a lubricant is pure water, tap water, river water or seawater. This document does not
apply to the water solution of chemicals, refrigerants, liquid fuels, etc.
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 1043-1, Plastics — Symbols and abbreviated terms — Part 1: Basic polymers and their special characteristics
ISO 4378-1, Plain bearings — Terms, definitions, classification and symbols — Part 1: Design, bearing materials
and their properties
ISO 4378-2, Plain bearings — Terms, definitions, classification and symbols — Part 2: Friction and wear
ISO 4378-3, Plain bearings — Terms, definitions, classification and symbols — Part 3: Lubrication
ISO 8044, Corrosion of metals and alloys — Vocabulary
3 Terms and defin
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