ISO 20054:2016

DRAFT INTERNATIONAL STANDARD
ISO/DIS 20054
ISO/TC 123/SC 7 Secretariat: JISC
Voting begins on: Voting terminates on:
2016-02-10 2016-05-10
Plain bearings — Bearings containing dispersed solid
lubricants
Paliers lisses - Paliers contenant des lubrifiants solides dispersés
ICS: 21.100.10
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ISO/DIS 20054:2016(E)
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©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2016

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ISO/DIS 20054:2016(E)

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ii © ISO 2016 – All rights reserved

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ISO/DIS 20054
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 20054 was prepared by Technical Committee ISO/TC 123, Plain bearings, Subcommittee SC 7,
Special types of plain bearings.
© ISO 2015 – All rights reserved iii

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DRAFT INTERNATIONAL STANDARD ISO/DIS 20054

Plain bearings — Bearings containing dispersed solid lubricants
1 Scope
This International Standard specifies a bearing containing dispersed solid lubricants which has been
used as a solid lubricant bearing.
NOTE In the solid lubricant bearing among self-lubricating bearings, there is a solid type, a coated type, an
embedded type and a dispersed type which is specified by this standard.
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 3547-1, Plain bearings — Wrapped bushes — Part 1: Dimensions
ISO 3547-2, Plain bearings — Wrapped bushes — Part 2: Test data for outside and inside diameters
ISO 3547-3, Plain bearings — Wrapped bushes — Part 3: Lubrication holes, grooves and indentations
ISO 3547-4, Plain bearings — Wrapped bushes — Part 4: Materials
ISO 3547-5, Plain bearings — Wrapped bushes — Part 5: Checking the outside diameter
ISO 3547-6, Plain bearings — Wrapped bushes — Part 6: Checking the inside diameter
ISO 3547-7, Plain bearings — Wrapped bushes — Part 7: Measurement of wall thickness of thin-walled
bushes
3 Symbols and units
See Table 1.
Table 1 — Symbols and units
Symbol Description Unit
B Width of the bush mm
D Inside diameter of the bush mm
i
D Outside diameter of the bush mm
o
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ISO/DIS 20054
4 Characteristics
4.1 Structure
A bearing containing dispersed solid lubricants is made of sintered composite materials that contain
solid lubricants dispersed uniformly in the metal matrix and is manufactured by powder metallurgy
(see Figure 1).
This standard includes multi-layered bearings with the sintered layer on a steel backing and both
seamless and wrapped bushes (see Figure 2).
Figure 3 shows a typical microstructure of the bearings containing dispersed solid lubricants. The
dispersed solid lubricants in the metal matrix vary in grain size and volume.


a) seamless bush a) seamless bush
(fine solid lubricants type) (coarse solid lubricants type)
Figure 1 — Overview of bearings containing dispersed solid lubricants (Single-layered)


a) seamless bush b) wrapped bush
Key
1 sintered layer
2 steel backing
Figure 2 — Overview of bearings containing dispersed solid lubricants (Multi-layered)
2 © ISO 2015 – All rights reserved

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ISO/DIS 20054

a) fine solid lubricants type b) coarse solid lubricants type
Key
1 metal matrix
2 dispersed solid lubricant
Figure 3 — Microstructure of a bearing containing dispersed solid lubricants
4.2 Bearing characteristics
A bearing containing dispersed solid lubricants obtains its sliding performance from the self-lubricating
effects of solid lubricants and the mechanical strength of metal matrix.
The sliding performance and mechanical strength vary according to the volume of solid lubricants.
Higher sliding performance requires more solid lubricants, while higher mechanical strength requires
less solid lubricants.
Since solid lubricants are dispersed over the entire material, the bearings are particularly suitable for
extra low speed or micro-motion applications, minimising static friction to achieve smooth sliding at the
start of motion.
The solid lubricants are drawn out over both surfaces from the bearing material when it slides against
the mating surface, forming a solid lubricant film. As the solid lubricant film is consumed, it is
replenished from the bearing material to maintain a continuous film throughout the life of the product
(see Figure 4).

Key
1 mating member
2 metal matrix
3 dispersed solid lubricant
4 solid lubricant film
A sliding direction
Figure 4 — Lubricating mechanism of a bearing containing dispersed solid lubricants
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ISO/DIS 20054
4.3 Applicable field
The bearing can be used for rotational motion, reciprocating motion, oscillating motion and frequent
start/stop cycles. The bearing is also used in such applications where no fluid lubrication can be
expected because of high load and low speed operation. Bearings with appropriate materials are suited
to applications with high or low temperature, liquids, gases and in vacuo.
The bearing has been developed to operate satisfactorily without oil or grease lubricants. However, if
the application permits, oil or grease may be utilised to improve bearing durability, prevent dust from
entering the bearing, flush out wear debris or prevent corrosion of the bearing components.
5 Material
5.1 Metal matrix
The constituent elements of the metal matrix in the bearing define the physical, chemical and
mechanical properties of the bearing. The chemical composition and manufacturing methods (sintering
and heat treatment) influence the bearing metal matrix properties.
Metal matrix base materials are principally copper, nickel or iron. Table 2 shows the operating
temperature for the alloy types.
Table 2 — Types of alloy and their operating temperature
a
Operating temperature
Alloy type
°C
Copper based alloys -200 to 450
Nickel based alloys -200 to 600
Iron based alloys  0 to 700
a
  Operating temperature varies according to the composition.

The most commonly-used, copper-based metal matrix group is Cu-Sn, but Cu-Ni-Sn and Cu-Ni-Fe alloys
offer enhanced thermal resistance and strength.
The nickel-based metal matrix group includes Ni-Cu-Fe alloys, which offer high corrosion resistance.
The iron-based metal matrix group includes Fe-Cu alloys which offer higher thermal resistance than
copper-based alloys by the formation of iron oxide lubricant films. In addition there are high-heat
resistant Fe-Ni-Cu alloys and stainless alloys (Fe-Cr-Ni alloys, etc.).
Metal matrix may contain small additive additions to enhance performance. The surface of metal matrix
may have an additional running-in coating.
A guide for the selection of a bearing metal matrix for bearings containing dispersed solid lubricants is
shown in Figure A.1 of Annex A.
5.2 Solid lubricant
Many types of solid lubricants are available. They are selected to suit the operating conditions because
their friction performances are influenced by the operating environment. The majority of bearings
incorporate graphite and molybdenum disulphide as solid lubricants. Other solid lubricants with low
friction, suited to demanding environments, include tungsten disulphid
...