Sintered metal material - Specifications (ISO 5755:2022)

This document specifies the requirements for the chemical composition and the mechanical and physical properties of sintered metal materials used for bearings and structural parts.

Sintermetallwerkstoffe - Anforderungen (ISO 5755:2022)

Matériaux métalliques frittés - Spécifications (ISO 5755:2022)

Le présent document spécifie les exigences relatives à la composition chimique et aux propriétés physiques et mécaniques des matériaux métalliques frittés utilisés pour les paliers et les pièces mécaniques.

Sintrane kovine - Specifikacije (ISO 5755:2022)

General Information

Status
Published
Public Enquiry End Date
27-Mar-2022
Publication Date
14-Nov-2022
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
08-Nov-2022
Due Date
13-Jan-2023
Completion Date
15-Nov-2022

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SLOVENSKI STANDARD
SIST EN ISO 5755:2022
01-december-2022
Nadomešča:
SIST EN ISO 5755:2012
Sintrane kovine - Specifikacije (ISO 5755:2022)
Sintered metal material - Specifications (ISO 5755:2022)
Sintermetallwerkstoffe - Anforderungen (ISO 5755:2022)
Matériaux métalliques frittés - Spécifications (ISO 5755:2022)
Ta slovenski standard je istoveten z: EN ISO 5755:2022
ICS:
77.160 Metalurgija prahov Powder metallurgy
SIST EN ISO 5755:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 5755:2022
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SIST EN ISO 5755:2022
EN ISO 5755
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2022
EUROPÄISCHE NORM
ICS 77.160 Supersedes EN ISO 5755:2012
English Version
Sintered metal material - Specifications (ISO 5755:2022)

Matériaux métalliques frittés - Spécifications (ISO Sintermetallwerkstoffe - Anforderungen (ISO

5755:2022) 5755:2022)
This European Standard was approved by CEN on 8 May 2022.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye 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

© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 5755:2022 E

worldwide for CEN national Members.
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SIST EN ISO 5755:2022
EN ISO 5755:2022 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 5755:2022
EN ISO 5755:2022 (E)
European foreword

This document (EN ISO 5755:2022) has been prepared by Technical Committee ISO/TC 119 "Powder

metallurgy" in collaboration with CCMC.

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 April 2023, and conflicting national standards shall be

withdrawn at the latest by April 2023.

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 5755:2012.

Any feedback and questions on this document should be directed to the users’ national standards

body/national committee. A complete listing of these bodies can be found on the CEN website.

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, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the

United Kingdom.
Endorsement notice

The text of ISO 5755:2022 has been approved by CEN as EN ISO 5755:2022 without any modification.

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SIST EN ISO 5755:2022
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SIST EN ISO 5755:2022
INTERNATIONAL ISO
STANDARD 5755
Fourth edition
2022-10
Sintered metal material —
Specifications
Matériaux métalliques frittés — Spécifications
Reference number
ISO 5755:2022(E)
© ISO 2022
---------------------- Page: 7 ----------------------
SIST EN ISO 5755:2022
ISO 5755:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2022 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 5755:2022
ISO 5755:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Sampling ....................................................................................................................................................................................................................... 3

5 Test methods for normative properties ...................................................................................................................................... 3

5.1 General ........................................................................................................................................................................................................... 3

5.2 Chemical analysis ................................................................................................................................................................................. 3

5.3 Open porosity .......................................................................................................................................................................................... 3

5.4 Mechanical properties ..................................................................................................................................................................... 3

5.4.1 General ........................................................................................................................................................................................ 3

5.4.2 Tensile properties ........................................................................................................................................... ................... 4

5.4.3 Radial crushing strength ............................................................................................................................................ 4

6 Test methods for informative properties .................................................................................................................................. 5

6.1 General ........................................................................................................................................................................................................... 5

6.2 Density ........................................................................................................................................................................................................... 5

6.3 Tensile strength ..................................................................................................................................................................................... 5

6.4 Tensile yield strength ....................................................................................................................................................................... 5

6.5 Elongation ................................................................................................................................................................................................... 5

6.6 Young’s modulus.................................................................................................................................................................................... 5

6.7 Poisson’s ratio .......................................................................................................................................................................................... 5

6.8 Impact energy .......................................................................................................................................................................................... 6

6.9 Compressive yield strength ........................................................................................................................................................ 6

6.10 Transverse rupture strength ..................................................................................................................................................... 6

6.11 Fatigue strength .................................................................................................................................................................................... 6

6.11.1 General ........................................................................................................................................................................................ 6

6.11.2 Rotating bending fatigue strength ..................................................................................................................... 6

6.11.3 Plane-bending fatigue strength ............................................................................................................................ 6

6.11.4 Axial fatigue strength .................................................................................................................................................... 7

6.12 Apparent hardness ........................................................................................................................................... ................................... 7

6.13 Coefficient of linear expansion ........................................................................................................................................... ...... 7

7 Specifications .......................................................................................................................................................................................................... 7

8 Designations ............................................................................................................................................................................................................. 7

Annex A (normative) Designation system ..................................................................................................................................................35

Annex B (informative) Microstructures .......................................................................................................................................................38

Annex C (informative) Equivalence of standards of powder metallurgy materials ......................................53

Bibliography .............................................................................................................................................................................................................................68

iii
© ISO 2022 – All rights reserved
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SIST EN ISO 5755:2022
ISO 5755:2022(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 of 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

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 119, Powder metallurgy, Subcommittee

SC 5, Specifications for powder metallurgical materials (excluding hardmetals), in collaboration with the

European Committee for Standardization (CEN) Technical Committee CEN/SS M11, Powder metallurgy,

in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

This fourth edition cancels and replaces the third edition (ISO 5755:2012), which has been technically

revised.
The main changes are as follows:

— Annex B has been updated to include information on metallography of sintered materials;

— a new Annex C has been added to include tables of equivalences of the materials of the standard

with the materials of other international standards of habitual use.

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.
© ISO 2022 – All rights reserved
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SIST EN ISO 5755:2022
INTERNATIONAL STANDARD ISO 5755:2022(E)
Sintered metal material — Specifications
1 Scope

This document specifies the requirements for the chemical composition and the mechanical and

physical properties of sintered metal materials used for bearings and structural parts.

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 1099, Metallic materials — Fatigue testing — Axial force-controlled method

ISO 2738, Sintered metal materials, excluding hardmetals — Permeable sintered metal materials —

Determination of density, oil content and open porosity
ISO 2739, Sintered metal bushings — Determination of radial crushing strength
ISO 2740, Sintered metal materials, excluding hardmetals — Tensile test pieces
ISO 2795, Plain bearings — Sintered bushes — Dimensions and tolerances

ISO 3325, Sintered metal materials, excluding hardmetals — Determination of transverse rupture strength

ISO 3954, Powders for powder metallurgical purposes — Sampling

ISO 4498, Sintered metal materials, excluding hardmetals — Determination of apparent hardness and

microhardness

ISO 5754, Sintered metal materials, excluding hardmetals — Unnotched impact test piece

ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature

ISO 7625, Sintered metal materials, excluding hardmetals — Preparation of samples for chemical analysis

for determination of carbon content

ISO 14317, Sintered metal materials excluding hardmetals — Determination of compressive yield strength

ASTM E228, Standard Test Method for Linear Thermal Expansion of Solid Materials with a Push-Rod

Dilatometer

ASTM E1875, Standard Test Method for Dynamic Young’s Modulus, Shear Modulus, and Poisson’s Ratio by

Sonic Resonance
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology 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/
© ISO 2022 – All rights reserved
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SIST EN ISO 5755:2022
ISO 5755:2022(E)
3.1
tensile strength

ability of a test specimen to resist fracture when a pulling force is applied in a direction parallel to its

longitudinal axis

Note 1 to entry: It is equal to the maximum load divided by the original cross-sectional area.

Note 2 to entry: It is expressed in MPa.
3.2
tensile yield strength
p0,2

load at which the material exhibits a 0,2 % offset from proportionality on a stress-strain curve in

tension, divided by the original cross-sectional area
Note 1 to entry: It is expressed in MPa.
3.3
Young’s modulus

ratio of normal stress to corresponding strain for tensile or compressive stresses below the proportional

limit of the material
Note 1 to entry: It is expressed in GPa.
3.4
Poisson’s ratio

absolute value of the ratio of transverse strain to the corresponding axial strain, resulting from

uniformally distributed axial stress below the proportional limit of the material

3.5
impact energy
measurement of the energy absorbed when fracturing a specimen with a single blow
Note 1 to entry: It is expressed in Joules (J).
3.6
compressive yield strength
stress at which a material exhibits a specified permanent set
Note 1 to entry: It is expressed in MPa.
3.7
transverse rupture strength

stress, calculated from the bending strength formula, required to break a specimen of a given dimension

Note 1 to entry: It is expressed in MPa.
3.8
fatigue strength

maximum alternating stress that can be sustained for a specific number of cycles without failure, the

stress being reversed with each cycle unless otherwise stated
Note 1 to entry: It is expressed in MPa.
3.9
radial crushing strength

radial stress required to fracture a hollow cylindrical part of specified dimensions

Note 1 to entry: It is expressed in MPa.
© ISO 2022 – All rights reserved
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SIST EN ISO 5755:2022
ISO 5755:2022(E)
3.10
density
mass per unit volume of the material
Note 1 to entry: It is expressed in g/cm .
3.11
apparent hardness

resistance of a powder metallurgical (PM) material to indentation, tested under specified conditions

Note 1 to entry: For PM materials, it is a function of the density of the material.

3.12
open porosity

oil content after full impregnation, divided by the volume of the test piece, and multiplied by 100

Note 1 to entry: It is expressed as a volume percentage.
3.13
coefficient of linear expansion
change in length per unit length per degree change in temperature
−6 −1
Note 1 to entry: It is expressed in 10 K .
4 Sampling

Sampling of powders to produce standard test pieces shall be carried out in accordance with ISO 3954.

5 Test methods for normative properties
5.1 General

The following test methods shall be used to determine the normative properties given in Tables 1 to 18.

5.2 Chemical analysis

The chemical composition table for each material lists the principal elements by minimum and

maximum mass percentage before any additional process, such as oil impregnation, resin impregnation

or steam treatment, has taken place. “Other elements” may include minor amounts of elements added

for specific purposes and is reported as a maximum percentage.

Whenever possible, and always in cases of dispute, the methods of chemical analysis shall be those

specified in the relevant International Standards. If no International Standard is available, the method

may be agreed upon and specified at the time of enquiry and order.

Samples for the determination of total carbon content shall be prepared in accordance with ISO 7625.

Determination of the total carbon content can be in accordance with ISO 437.
5.3 Open porosity
The open porosity shall be determined in accordance with ISO 2738.
5.4 Mechanical properties
5.4.1 General

The as-sintered mechanical properties given in Tables 1 to 18 were determined on pressed and sintered

test pieces with a mean chemical composition. The heat-treated mechanical properties given in Tables 1

© ISO 2022 – All rights reserved
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SIST EN ISO 5755:2022
ISO 5755:2022(E)

to 18 were determined on test bars which were either pressed and sintered or machined from pressed

and sintered blanks. They are intended as a guide to the initial selection of materials . When selecting

powder metallurgical (PM) materials, it should be taken into account that the properties depend not

only on the chemical composition and density, but also on the production methods. The properties of

sintered materials giving satisfactory service in particular applications may not necessarily be the same

as those of wrought or cast materials that might otherwise be used. Therefore, liaison with prospective

suppliers is recommended They may also be used as a basis for specifying any special tests that may be

indicated on the drawing.

The mechanical properties shall neither be calculated from hardness values nor be determined on

tensile test pieces taken from a component and used for verifying the values given in Tables 1 to 18.

If the customer requires that a specified level of mechanical properties be obtained by tests on the

component, these shall be agreed with the supplier and shall be stated on the drawing and/or any

technical documentation of the customer referred to on the drawing.
5.4.2 Tensile properties

The ultimate tensile strength and the yield strength shall be determined in accordance with ISO 2740

and ISO 6892-1. For heat-treated materials, tensile strength and yield strength are approximately equal

and, in this case, tensile strength is specified.

The normative yield strengths (as-sintered condition) and ultimate tensile strengths (heat-treated

condition) are shown as minimum values. These strengths may be used in designing PM part

applications. To select a material which is optimum in both properties and cost-effectiveness, it is

essential that the part application be discussed with the PM parts manufacturer.

The minimum values were developed from tensile specimens prepared specifically for evaluating PM

materials.

Tensile specimens machined from commercial parts may differ from those obtained from prepared

tensile specimens. To evaluate the part strength, it is recommended that static or dynamic proof-testing

be agreed between the purchaser and the manufacturer and carried out on the first production lot of

parts. The results of testing to failure can be used statistically to determine a minimum breaking force

for future production lots.

Acceptable strength can also be demonstrated by processing tensile specimens prepared specifically

for evaluating PM materials manufactured from the same batch of powder as the production parts and

processed with them.

As indicated above, the testing of test bars machined from the PM component is the least desirable

method for demonstrating minimum properties.

For heat-treated properties, the test bars were quench-hardened and tempered to increase the strength,

hardness and wear resistance. Tempering is essential to develop the properties given in this document.

Heat-treat equipment that utilizes a gas atmosphere or vacuum is recommended. The use of liquid salts

is not recommended due to entrapment of the salts in the porosity causing “salt bleed-out” and “internal

corrosion”. Some materials may be heat-treated directly after the sintering process by controlling the

cooling rate within the sintering furnace. This process is usually known as “sinter hardening”. Materials

processed by this route also require tempering to develop their optimum strengths.

5.4.3 Radial crushing strength

The radial crushing strength shall be determined in accordance with ISO 2739. The wall thicknesses of

test pieces to be used shall be in the range covered by ISO 2795. For test pieces outside this range, the

specified radial crushing strength values are different and shall be agreed between the customer and

the supplier.
© ISO 2022 – All rights reserved
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SIST EN ISO 5755:2022
ISO 5755:2022(E)
6 Test methods for informative properties
6.1 General

Typical values are given for each material; these include tensile and yield strengths. These typical

values are given for general guidance only. They should not be used as minimum values.

These typical properties should be achievable through normal manufacturing processing. Again,

any specific tests on components should be discussed and agreed between the purchaser and the

manufacturer.
6.2 Density

The density shall be determined in accordance with ISO 2738. Density is normally determined after the

removal of any oils or non-metallic materials from the porosity and is known as the “dry density”. The

“wet density” is sometimes reported on production bearings or parts, this is the mass per unit volume,

including any oil or non-metallic material that has impregnated the component.
6.3 Tensile strength

The tensile strength shall be determined in accordance with ISO 2740 and ISO 6892-1.

6.4 Tensile yield strength

The tensile yield strength shall be determined in accordance with ISO 2740 and ISO 6892-1.

6.5 Elongation

Elongation (plastic) shall be determined in accordance with ISO 6892-1. It is expressed as a percentage

of the original gauge length (usually 25 mm), and is determined by on measuring the increase in gauge

length after the fracture, providing the fracture takes place within the gauge length. Elongation can

also be measured with a break-away extensometer on a tensile specimen. The recorded stress/strain

curve displays total elongation (elastic and plastic). The elastic strain shall be subtracted from the

total elongation to give the plastic elongation (this can sometimes be provided with the test machine’s

software).
6.6 Young’s modulus

Young’s modulus shall be determined in accordance with ASTM E1875. Data for the elastic constants in

this document were generated from resonant frequency testing. Formula (1) relates the three elastic

constants:
vE=()/2G −1 (1)
where
v is Poisson’s ratio;
E is Young’s modulus;
G is the shear modulus.
6.7 Poisson’s ratio
Poisson’s ratio shall be determined in accordance with ASTM E1875.
© ISO 2022 – All rights reserved
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SIST EN ISO 5755:2022
ISO 5755:2022(E)
6.8 Impact energy

The impact energy shall be determined in accordance with ISO 5754. The data in this document were

obtained using an unnotched Charpy specimen.
6.9 Compressive yield strength

The compressive yield strength shall be determined in accordance with ISO 14317. For certain heat-

treated materials listed in the tables, the hardenability is not sufficient to completely through-harden

the 9,00 mm diameter test specimen. Due to variation in hardenability among the heat-treated steels

listed in the tables, the compressive yield strength data are appropriate only for 9,00 mm sections.

Typically, smaller cross-sections have higher compressive yield strengths and larger sections have

somewhat lower strengths due to the hardenability response. Since the cross-section of the tensile

yield test specimen is smaller than the compressive yield specimen, a direct correspondence between

tensile and compressive yield strength data are not possible.
6.10 Transverse rupture strength
The transverse rupture strength shall b
...

SLOVENSKI STANDARD
oSIST prEN ISO 5755:2022
01-marec-2022
Sintrane kovine - Specifikacije (ISO/DIS 5755:2022)
Sintered metal materials - Specifications (ISO/DIS 5755:2022)
Sintermetallwerkstoffe - Anforderungen (ISO/DIS 5755:2022)
Matériaux métalliques frittés - Spécifications (ISO/DIS 5755:2022)
Ta slovenski standard je istoveten z: prEN ISO 5755
ICS:
77.160 Metalurgija prahov Powder metallurgy
oSIST prEN ISO 5755:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 5755:2022
---------------------- Page: 2 ----------------------
oSIST prEN ISO 5755:2022
DRAFT INTERNATIONAL STANDARD
ISO/DIS 5755
ISO/TC 119/SC 5 Secretariat: UNE
Voting begins on: Voting terminates on:
2022-01-04 2022-03-29
Sintered metal materials — Specifications
Matériaux métalliques frittés — Spécifications
ICS: 77.160
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 5755:2022(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022
---------------------- Page: 3 ----------------------
oSIST prEN ISO 5755:2022
ISO/DIS 5755:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2022 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 5755:2022
ISO/DIS 5755:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 2

4 Sampling ....................................................................................................................................................................................................................... 3

5 Test methods for normative properties ...................................................................................................................................... 3

5.1 General ........................................................................................................................................................................................................... 3

5.2 Chemical analysis ................................................................................................................................................................................. 3

5.3 Open porosity .......................................................................................................................................................................................... 3

5.4 Mechanical properties ..................................................................................................................................................................... 3

5.4.1 General ........................................................................................................................................................................................ 3

5.4.2 Tensile properties ........................................................................................................................................... ................... 4

5.4.3 Radial crushing strength ............................................................................................................................................ 4

6 Test methods for informative properties .................................................................................................................................. 4

6.1 General ........................................................................................................................................................................................................... 4

6.2 Density ........................................................................................................................................................................................................... 4

6.3 Tensile strength ..................................................................................................................................................................................... 5

6.4 Tensile yield strength ....................................................................................................................................................................... 5

6.5 Elongation ................................................................................................................................................................................................... 5

6.6 Young’s modulus.................................................................................................................................................................................... 5

6.7 Poisson’s ratio .......................................................................................................................................................................................... 5

6.8 Impact energy .......................................................................................................................................................................................... 5

6.9 Compressive yield strength ........................................................................................................................................................ 5

6.10 Transverse rupture strength ..................................................................................................................................................... 6

6.11 Fatigue strength .................................................................................................................................................................................... 6

6.11.1 General ........................................................................................................................................................................................ 6

6.11.2 Rotating bending fatigue strength ..................................................................................................................... 6

6.11.3 Plane-bending fatigue strength ............................................................................................................................ 6

6.11.4 Axial fatigue strength .................................................................................................................................................... 6

6.12 Apparent hardness ........................................................................................................................................... ................................... 6

6.13 Coefficient of linear expansion ........................................................................................................................................... ...... 7

7 Specifications .......................................................................................................................................................................................................... 7

8 Designations ............................................................................................................................................................................................................. 7

Annex A (normative) Designation system ..................................................................................................................................................38

Annex B (informative) Microstructures .......................................................................................................................................................41

Annex C (Informative) Equivalence of standards of powder metallurgy materials ......................................54

Bibliography .............................................................................................................................................................................................................................72

iii
© ISO 2022 – All rights reserved
---------------------- Page: 5 ----------------------
oSIST prEN ISO 5755:2022
ISO/DIS 5755:2022(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

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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

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on the ISO list of patent declarations received (see www.iso.org/patents).

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www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 119, Powder metallurgy, Subcommittee

SC 5, Specifications for powder metallurgical materials (excluding hardmetals).

This fourth edition cancels and replaces the third edition (ISO 5755:2012), which has been technically

revised.
The main changes compared to the previous edition are as follows:
— Inclusion of an annex on metallography of sintered materials.

— Inclusion of a table of equivalences of the materials of the standard with the materials of other

international standards of habitual use:
— Materials for bearings.
— Materials for structural parts.
— Copper based materials for structural parts.
— Aluminium for structural parts.
— Soft magnetic materials and new materials.

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.
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DRAFT INTERNATIONAL STANDARD ISO/DIS 5755:2022(E)
Sintered metal materials — Specifications
1 Scope

This International Standard specifies the requirements for the chemical composition and the

mechanical and physical properties of sintered metal materials used for bearings and structural parts.

When selecting powder metallurgical (PM) materials, it should be taken into account that the properties

depend not only on the chemical composition and density, but also on the production methods. The

properties of sintered materials giving satisfactory service in particular applications may not

necessarily be the same as those of wrought or cast materials that might otherwise be used. Therefore,

liaison with prospective suppliers is recommended.
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 437, Steel and cast iron — Determination of total carbon content — Combustion gravimetric method

ISO 1099, Metallic materials — Fatigue testing — Axial force-controlled method
ISO 1143, Metallic materials — Rotating bar bending fatigue testing

ISO 2738, Sintered metal materials, excluding hardmetals — Permeable sintered metal materials —

Determination of density, oil content and open porosity
ISO 2739, Sintered metal bushings — Determination of radial crushing strength
ISO 2740, Sintered metal materials, excluding hardmetals — Tensile test pieces
ISO 2795, Plain bearings — Sintered bushes — Dimensions and tolerances

ISO 3325, Sintered metal materials, excluding hardmetals — Determination of transverse rupture strength

ISO 3928, Sintered metal materials, excluding hardmetals — Fatigue test pieces
ISO 3954, Powders for powder metallurgical purposes — Sampling

ISO 4498, Sintered metal materials, excluding hardmetals — Determination of apparent hardness and

microhardness

ISO 5754, Sintered metal materials, excluding hardmetals — Unnotched impact test piece

ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature

ISO 7625, Sintered metal materials, excluding hardmetals — Preparation of samples for chemical analysis

for determination of carbon content

ISO 14317, Sintered metal materials excluding hardmetals — Determination of compressive yield strength

ASTM E228, Standard Test Method for Linear Thermal Expansion of Solid Materials with a Push-Rod

Dilatometer

ASTM E1875, Standard Test Method for Dynamic Young’s Modulus, Shear Modulus, and Poisson’s Ratio by

Sonic Resonance
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IEC 60404-8-9, Magnetic materials — Part 8: Specifications for individual materials - Section 9: Standard

specification for sintered soft magnetic materials
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
tensile strength

ability of a test specimen to resist fracture when a pulling force is applied in a direction parallel to its

longitudinal axis – expressed in MPa

Note 1 to entry: It is equal to the maximum load divided by the original cross-sectional area.

3.2
tensile yield strength
p0,2

load at which the material exhibits a 0,2 % offset from proportionality on a stress-strain curve in

tension, divided by the original cross-sectional area – expressed in MPa
3.3
Young’s modulus

ratio of normal stress to corresponding strain for tensile or compressive stresses below the proportional

limit of the material – expressed in GPa
3.4
Poisson’s ratio

absolute value of the ratio of transverse strain to the corresponding axial strain, resulting from

uniformally distributed axial stress below the proportional limit of the material

3.5
impact energy

measurement of the energy absorbed when fracturing a specimen with a single blow – measured in

Joules (J)
3.6
compressive yield strength
stress at which a material exhibits a specified permanent set – expressed in MPa
3.7
transverse rupture strength

stress, calculated from the bending strength formula, required to break a specimen of a given dimension

– expressed in MPa
3.8
fatigue strength

maximum alternating stress that can be sustained for a specific number of cycles without failure, the

stress being reversed with each cycle unless otherwise stated – expressed in MPa
3.9
radial crushing strength

radial stress required to fracture a hollow cylindrical part of specified dimensions – expressed in MPa

3.10
density
mass per unit volume of the material – expressed in g/cm
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3.11
apparent hardness

resistance of a powder metallurgical (PM) material to indentation, tested under specified conditions;

for PM materials, it is a function of the density of the material
3.12
open porosity

oil content after full impregnation, divided by the volume of the test piece, and multiplied by 100 –

expressed as a volume percentage
3.13
coefficient of linear expansion
−6 −1

change in length per unit length per degree change in temperature – expressed in 10 K

4 Sampling

Sampling of powders to produce standard test pieces shall be carried out in accordance with ISO 3954.

5 Test methods for normative properties
5.1 General

The following test methods shall be used to determine the normative properties given in Tables 1 to 18.

5.2 Chemical analysis

The chemical composition table for each material lists the principal elements by minimum and

maximum mass percentage before any additional process, such as oil impregnation, resin impregnation

or steam treatment, has taken place. “Other elements” may include minor amounts of elements added

for specific purposes and is reported as a maximum percentage.

Whenever possible, and always in cases of dispute, the methods of chemical analysis shall be those

specified in the relevant International Standards. If no International Standard is available, the method

may be agreed upon and specified at the time of enquiry and order.

Samples for the determination of total carbon content shall be prepared in accordance with ISO 7625.

Determination of the total carbon content shall be in accordance with ISO 437.
5.3 Open porosity
The open porosity shall be determined in accordance with ISO 2738.
5.4 Mechanical properties
5.4.1 General

The as-sintered mechanical properties given in Tables 1 to 18 were determined on pressed and sintered

test pieces with a mean chemical composition. The heat-treated mechanical properties given in Tables 1

to 18 were determined on test bars which were either pressed and sintered or machined from pressed

and sintered blanks. They are intended as a guide to the initial selection of materials (see also Clause 1).

They may also be used as a basis for specifying any special tests that may be indicated on the drawing.

The mechanical properties shall neither be calculated from hardness values nor be determined on

tensile test pieces taken from a component and used for verifying the values given in Tables 1 to 18.

If the customer requires that a specified level of mechanical properties be obtained by tests on the

component, these shall be agreed with the supplier and shall be stated on the drawing and/or any

technical documentation of the customer referred to on the drawing.
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5.4.2 Tensile properties

The ultimate tensile strength and the yield strength shall be determined in accordance with ISO 2740

and, ISO 6892-1. For heat-treated materials, tensile strength and yield strength are approximately equal

and, in this case, tensile strength is specified.

The normative yield strengths (as-sintered condition) and ultimate tensile strengths (heat-treated

condition) are shown as minimum values. These strengths may be used in designing PM part

applications. To select a material which is optimum in both properties and cost-effectiveness, it is

essential that the part application be discussed with the PM parts manufacturer.

The minimum values were developed from tensile specimens prepared specifically for evaluating PM

materials.

Tensile specimens machined from commercial parts may differ from those obtained from prepared

tensile specimens. To evaluate the part strength, it is recommended that static or dynamic proof-testing

be agreed between the purchaser and the manufacturer and carried out on the first production lot of

parts. The results of testing to failure can be used statistically to determine a minimum breaking force

for future production lots.

Acceptable strength can also be demonstrated by processing tensile specimens prepared specifically

for evaluating PM materials manufactured from the same batch of powder as the production parts and

processed with them.

As indicated above, the testing of test bars machined from the PM component is the least desirable

method for demonstrating minimum properties.

For heat-treated properties, the test bars were quench-hardened and tempered to increase the

strength, hardness and wear resistance. Tempering is essential to develop the properties given

in this International Standard. Heat-treat equipment that utilizes a gas atmosphere or vacuum is

recommended. The use of liquid salts is not recommended due to entrapment of the salts in the porosity

causing “salt bleed-out” and “internal corrosion”. Some materials may be heat-treated directly after the

sintering process by controlling the cooling rate within the sintering furnace. This process is usually

known as “sinter hardening”. Materials processed by this route also require tempering to develop their

optimum strengths.
5.4.3 Radial crushing strength

The radial crushing strength shall be determined in accordance with ISO 2739. The wall thicknesses of

test pieces to be used shall be in the range covered by ISO 2795. For test pieces outside this range, the

specified radial crushing strength values are different and shall be agreed between the customer and

the supplier.
6 Test methods for informative properties
6.1 General

Typical values are given for each material; these include tensile and yield strengths. These typical

values are given for general guidance only. They should not be used as minimum values.

These typical properties should be achievable through normal manufacturing processing. Again,

any specific tests on components should be discussed and agreed between the purchaser and the

manufacturer.
6.2 Density

Density is expressed in grams per cubic centimetre (g/cm ). The density shall be determined in

accordance with ISO 2738. Density is normally determined after the removal of any oils or non-metallic

materials from the porosity and is known as the “dry density”. The “wet density” is sometimes reported

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on production bearings or parts, this is the mass per unit volume, including any oil or non-metallic

material that has impregnated the component.
6.3 Tensile strength

The tensile strength shall be determined in accordance with ISO 2740 and ISO 6892-1.

6.4 Tensile yield strength

The tensile yield strength shall be determined in accordance with ISO 2740 and ISO 6892-1.

6.5 Elongation

Elongation (plastic) shall be determined in accordance with ISO 6892-1. It is expressed as a percentage

of the original gauge length (usually 25 mm), and is determined by on measuring the increase in gauge

length after the fracture, providing the fracture takes place within the gauge length. Elongation can

also be measured with a break-away extensometer on a tensile specimen. The recorded stress/strain

curve displays total elongation (elastic and plastic). The elastic strain must be subtracted from the

total elongation to give the plastic elongation (this can sometimes be provided with the test machine’s

software).
6.6 Young’s modulus

Young’s modulus shall be determined in accordance with ASTM E1875. Data for the elastic constants in

this International Standard were generated from resonant frequency testing. An equation relating the

three elastic constants is:
vE= /21G − (1)
where
v is Poisson’s ratio;
E is Young’s modulus;
G is the shear modulus.
6.7 Poisson’s ratio
Poisson’s ratio shall be determined in accordance with ASTM E1875.
6.8 Impact energy

The impact energy shall be determined in accordance with ISO 5754. The data in this International

Standard were obtained using an unnotched Charpy specimen.
6.9 Compressive yield strength

The compressive yield strength shall be determined in accordance with ISO 14317. For certain heat-

treated materials listed in the tables, the hardenability is not sufficient to completely through-harden

the 9,00 mm diameter test specimen. Due to variation in hardenability among the heat-treated steels

listed in the tables, the compressive yield strength data are appropriate only for 9,00 mm sections.

Typically, smaller cross-sections have higher compressive yield strengths and larger sections have

somewhat lower strengths due to the hardenability response. Since the cross-section of the tensile

yield test specimen is smaller than the compressive yield specimen, a direct correspondence between

tensile and compressive yield strength data are not possible.
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6.10 Transverse rupture strength
The transverse rupture strength shall be determined in accordance with ISO 3325.

The strength formula in ISO 3325 is strictly valid only for non-ductile materials; nevertheless, it is

widely used for materials that bend at fracture and is useful for establishing comparative strengths.

Data for such materials are included as typical properties in ISO 3325.
6.11 Fatigue strength
6.11.1 General
The number of cycles survived should be stated with each strength listed.

For PM ferrous materials, like wrought ferrous materials, fatigue strengths of 10 cycles in duration

using unnotched specimens are considered to be sustainable indefinitely and are therefore considered

to be fatigue limits (also termed endurance limits). By contrast, non-ferrous PM materials do not have

10 cycle maximum fatigue strengths sustainable for indefinite times and these stress limits therefore

simply remain as the fatigue strength at 10 cycles.

The fatigue limits in this International Standard were generated through statistical analysis of the

test data. Due to the limited number of data points available for the analysis, these fatigue strengths

were determined as the 90 % survival stress, i.e. the fatigue stress at which 90 % of the test specimens

survived 10 cycles.

There are three methods of stressing the test specimens and each gives different fatigue strengths.

These are described in 6.11.2 to 6.11.4.
6.11.2 Rotating bending fatigue strength

This test method uses a machined, round, smooth test specimen (in accordance with ISO 3928), with

an R. R. Moore testing machine. Testing is conducted in accordance with ISO 1143. The specimen is

held at one end and rotated while it is stressed at the other end. The surface of the test bar is the most

highly stressed area and the centre line has a neutral stress. This test method gives the highest fatigue

strength.
6.11.3 Plane-bending fatigue strength

This method used for plane-bending fatigue uses a standard sintered fatigue test bar (in accordance

with ISO 3928) that is subjected to an alternating stress. This test method gives a slightly lower fatigue

strength than the rotating bending fatigue test, as more of the cross-sectional area is subjected to the

stress. Evaluation of fatigue strength is done according to the staircase method described in MPIF

Standard 56.
6.11.4 Axial fatigue strength

This method uses either a machined, round or standard sintered fatigue test bar (in accordance

with ISO 3928) that is tested in a test machine by clamping both ends and subjecting the test bar to

alternating stresses where R = −1. Testing is conducted in accordance with ISO 1099. As the whole of the

cross-section is stressed, this test method gives the lowest fatigue strength.
6.12 Apparent hardness

The apparent hardness shall be determined in accordance with ISO 4498. The hardness value of a

PM part when using a conventional indentation hardness tester is referred to as “apparent hardness”

because it rep
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