ISO 6624-3:2001

Internal combustion engines — Piston rings — Part 3: Keystone rings made of steel

Moteurs à combustion interne — Segments de piston — Partie 3: Segments trapézoïdaux en acier

General Information

• Status: Withdrawn
• Publication Date: 22-Aug-2001
• Withdrawal Date: 22-Aug-2001
• ICS: 43.060.10 - Engine block and internal components
• Technical Committee: ISO/TC 22/SC 34 - Propulsion, powertrain and powertrain fluids
• Drafting Committee: ISO/TC 22/SC 34/WG 4 - Piston rings
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 27-Apr-2017

Relations

• Revised: ISO 6624-3:2017 - Internal combustion engines — Piston rings — Part 3: Keystone rings made of steel
• Effective Date: 04-Nov-2015

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 6624-3
First edition
2001-08-15
Internal combustion engines —
Piston rings —
Part 3:
Keystone rings made of steel
Moteurs à combustion interne — Segments de piston —
Partie 3: Segments trapézoïdaux en acier
Reference number
ISO 6624-3:2001(E)
©
ISO 2001

---------------------- Page: 1 ----------------------
ISO 6624-3:2001(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.
© ISO 2001
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 [e-mail]
Web www.iso.ch
Printed in Switzerland
ii © ISO 2001 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 6624-3:2001(E)
Contents Page
Foreword.iv
Introduction.v
1 Scope .1
2 Normative references .1
3 Overview.1
4 Ring types and designation examples .2
4.1 Type T — Straight faced keystone ring 6°.2
4.2 Type TB — Symmetrical barrel faced keystone ring 6° .4
4.3 Type TBA — Asymmetrical barrel faced keystone ring 6° .6
4.4 Type TM — Taper faced keystone ring 6° .8
4.5 Type K — Straight faced keystone ring 15° .9
4.6 Type KB — Symmetrical barrel faced keystone ring 15°.10
4.7 Type KBA — Asymmetrical barrel faced keystone ring 15°.11
4.8 Type KM — Taper faced keystone ring 15°.12
5 Common features .13
5.1 Type T, TB, TBA, TM, K, KB, KBA, KM rings — Outside and inside rounded edges.13
5.2 Type T, TB, TBA, TM, K, KB, KBA, KM rings (positive twist type) — Internal bevel top side.13
5.3 Type TM or KM rings with partly cylindrical machined (LM) or lapped (LP) peripheral surface.14
5.4 Type T, TB, TBA, TM, K, KB, KBA, KM rings — Plating or coating configuration .14
6 Force Factors .17
Bibliography.24
© ISO 2001 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO 6624-3:2001(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 3.
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 part of ISO 6624 may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 6624-3 was prepared by Technical Committee ISO/TC 22, Road vehicles.
ISO 6624 consists of the following parts, under the general title Internal combustion engines — Piston rings:
� Part 1: Keystone rings made of cast iron
� Part 2: Half keystone rings made of cast iron
� Part 3: Keystone rings made of steel
� Part 4: Half keystone rings made of steel
iv © ISO 2001 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 6624-3:2001(E)
Introduction
ISO 6624 is one of a number of series of International Standards dealing with piston rings for reciprocating internal
combustion engines. Others are ISO 6621, ISO 6622, ISO 6623, ISO 6625, ISO 6626 and ISO 6627 (see
Bibliography for details).
The common features and dimensional tables presented in this part of ISO 6624 constitute a broad range of
variables and, in selecting a particular ring type, the designer must bear in mind the conditions under which it will
be required to operate.
[4] [5]
It is also essential that the designer refer to the specifications and requirements of ISO 6621-3 and ISO 6621-4
before completing a selection.
© ISO 2001 – All rights reserved v

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 6624-3:2001(E)
Internal combustion engines — Piston rings —
Part 3:
Keystone rings made of steel
1 Scope
This part of ISO 6624 specifies the essential dimensional features of keystone rings made of steel, types T, TB,
TBA, TM, K, KB, KBA and KM, having diameters of from 70 mm up to and including 160 mm, used in reciprocating
internal combustion piston engines.
2 Normative reference
The following normative document contains provisions which, through reference in this text, constitute provisions of
this part of ISO 6624. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 6624 are encouraged to investigate the
possibility of applying the most recent edition of the normative document indicated below. For undated references,
the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of
currently valid International Standards.
1)
ISO 6621-4:— , Internal combustion engines — Piston rings — Part 4: General specifications
3Overview
The keystone ring types are specified in Tables 1 to 3 and Figures 1 to 8. Their common features and the
dimensions of those features are specified in Tables 4 to 9 and Figures 9 to 15. Tables 10 and 11 give the force
factors for the different types of ring, while Table 12 and Table 13 give the dimensions and forces of keystone rings
6� and 15�, respectively.
1) To be published. (Revision of ISO 6621-4:1988)
© ISO 2001 – All rights reserved 1

---------------------- Page: 6 ----------------------
ISO 6624-3:2001(E)
4 Ring types and designation examples
4.1 Type T — Straight faced keystone ring 6°
4.1.1 General features
See Table 12 for dimensions and forces.
Dimensions in millimetres
Key
1 Reference plane
a
Due to manufacturing processing, side angle tolerances are not cumulative.
b
Nominal.
Figure 1 — Type T
4.1.2 Designation
EXAMPLE Designation of a piston ring complying with the requirements of ISO 6624-3, being a steel, 6° keystone ring
with straight faced peripheral surface (T), of nominal diameter d � 90 mm (90) and nominal ring width h � 2,5 mm (2,5), made
1 1
of CrSi alloyed steel, subclass 62 (MC62), and having a fully faced chromium plated peripheral surface with a minimum
thickness of 0,1 mm (CR2):
Piston ring ISO 6624-3 T - 90 ���� 2,5-MC62/CR2
2 © ISO 2001 – All rights reserved

---------------------- Page: 7 ----------------------
ISO 6624-3:2001(E)
(Blank page)
© ISO 2001 – All rights reserved 3

---------------------- Page: 8 ----------------------
ISO 6624-3:2001(E)
4.2 Type TB — Symmetrical barrel faced keystone ring 6°
4.2.1 General features
See Table 12 for dimensions and forces.
Dimensions in millimetres
Key
1 Reference plane
a
Due to manufacturing processing, side angle tolerances are not cumulative.
b
Nominal.
Figure 2 — Type TB
4 © ISO 2001 – All rights reserved

---------------------- Page: 9 ----------------------
ISO 6624-3:2001(E)
Table 1 — Symmetrical barrel dimensions
Dimensions in millimetres
a
h h h h t , t
h
1 25 26 27 2 3
8
Tolerance
2,0 0,40 1,00 � 0,30 1,60 1,2
0,003.0,015
� 0,40
2,5 0,45 1,25 2,05 1,6
3,0 0,50 1,50 2,50 2,0
� 0,50
0,005.0,020
3,5 0,55 1,75 2,95 2,4
4,0 0,60 2,00 � 0,60 3,40 0,005.0,023 2,8
a
Gauge width h , informative only, shall be used only if agreed between manufacturer and client.
8
4.2.2 Designation
EXAMPLE Designation of a piston ring complying with the requirements of ISO 6624-3, being a steel, 6° keystone ring
with barrel faced peripheral surface (TB), of nominal diameter d � 90 mm (90) and nominal ring width h � 2,5 mm (2,5), made
1 1
of martensitic steel (11 % Cr min.), subclass 65 (MC65), nitrided on the peripheral surface and side faces (NT) to a depth of
0,070 mm min. on the peripheral surface (070), and with an associated side face depth of a minimum of 0,020 mm:
Piston ring ISO 6624-3 TB - 90 ���� 2,5-MC65/NT070
© ISO 2001 – All rights reserved 5

---------------------- Page: 10 ----------------------
ISO 6624-3:2001(E)
4.3 Type TBA — Asymmetrical barrel faced keystone ring 6°
4.3.1 General features
See Table 12 for dimensions and forces.
Dimensions in millimetres
Key
1 Reference plane
2Mark
a
Due to manufacturing processing, side angle tolerances are not cumulative.
b
Nominal.
Figure 3 — Type TBA
6 © ISO 2001 – All rights reserved

---------------------- Page: 11 ----------------------
ISO 6624-3:2001(E)
Table 2 — Asymmetrical barrel dimensions
Dimensions in millimetres
a b b
h h h
h t t
1 26 27
25 2 3
Tolerance
2,00 0,40 0,60 � 0,20 1,50 0.0,007 0,009.0,030
2,50 0,45 0,70 1,80 0,011.0,035
� 0,25 0.0,008
3,00 0,55 0,80 2,10 0,012.0,038
3,50 0,60 0,90 2,40 0,012.0,040
� 0,30
0.0,009
4,00 0,65 0,95 2,80 0,013.0,045
a
h may be lowered for rings with reduced edge dimensions.
25
b
t or t or both may be varied as agreed between manufacturer and client.
2 3
4.3.2 Designation
EXAMPLE Designation of a piston ring complying with the requirements of ISO 6624-3, being a steel, 6° keystone ring
with asymmetrical barrel faced peripheral surface (TBA), of nominal diameter d � 90 mm (90) and nominal ring width
1
h � 2,5 mm (2,5), made of martensitic steel (17 % Cr min.), subclass 66 (MC66), nitrided on the peripheral surface and side
1
faces (NT) to a minimum depth of 0,070 mm on the peripheral surface (070), and with an associated side face depth of a
minimum of 0,020 mm:
Piston ring ISO 6624-3 TBA - 90 ���� 2,5-MC66/NT070
© ISO 2001 – All rights reserved 7

---------------------- Page: 12 ----------------------
ISO 6624-3:2001(E)
4.4 Type TM — Taper faced keystone ring 6°
4.4.1 General features
See Table 12 for dimensions and forces.
Dimensions in millimetres
Key
1 Reference plane
2Mark
a
Due to manufacturing processing, side angle tolerances are not cumulative.
b
Nominal.
Figure 4 — Type TM
Table 3 — Taper
Dimensions in minutes
a
Code Taper Internal twist feature designs
Tolerance
a
Tolerance
�50 �60
b
M1 10
0 0
M2 30
M3 60
�60 �70
0 0
M4 90
M5 120
a
For chromium plated rings with a tapered peripheral surface that is not ground, the tolerance shall be increased by 10 (e.g.
�70 �80
M3 � 60 tolerance: ; M3 with internal features � 60 tolerance: ).
0 0
b
M1 not for rings with partly cylindrical peripheral surface.
4.4.2 Designation
EXAMPLE Designation of a piston ring complying with the requirements of ISO 6624-3, being a steel, 6° keystone ring
with 10´ taper faced peripheral surface (TM1), of nominal diameter d � 90 mm (90) and nominal ring width h � 2,5 mm (2,5),
1 1
made of martensitic steel (11 % CR min.), subclass 65 (MC65), and having a fully faced chromium plated peripheral surface
with a minimum thickness of 0,1 mm (CR2):
Piston ring ISO 6624-3 TM1 - 90 ���� 2,5-MC65/CR2
8 © ISO 2001 – All rights reserved

---------------------- Page: 13 ----------------------
ISO 6624-3:2001(E)
4.5 Type K — Straight faced keystone ring 15°
4.5.1 General features
See Table 13 for dimensions and forces.
Dimensions in millimetres
Key
1 Reference plane
a
Due to manufacturing processing, side angle tolerances are not cumulative.
b
Nominal.
Figure 5 — Type K
4.5.2 Designation
EXAMPLE Designation of a piston ring complying with the requirements of ISO 6624-3, being a steel, 15° keystone ring
with straight faced peripheral surface (K), of nominal diameter d � 90 mm (90) and nominal ring width h � 2,5 mm (2,5), made
1 1
of CrMoV alloyed steel, subclass 61 (MC61), and having a fully faced chromium plated peripheral surface with a minimum
thickness of 0,1 mm (CR2):
Piston ring ISO 6624-3 K - 90 �� 2,5-MC61/CR2
��
© ISO 2001 – All rights reserved 9

---------------------- Page: 14 ----------------------
ISO 6624-3:2001(E)
4.6 Type KB — Symmetrical barrel faced keystone ring 15°
4.6.1 General features
See Table 1 for symmetrical barrel dimensions. See Table 13 for dimensions and forces.
Dimensions in millimetres
Key
1 Reference plane
a
Due to manufacturing processing, side angle tolerances are not cumulative.
b
Nominal.
Figure 6 — Type KB
4.6.2 Designation
EXAMPLE Designation of a piston ring complying with the requirements of ISO 6624-3, being a steel, 15° keystone ring
with barrel faced peripheral surface (KB), of nominal diameter d � 90 mm (90) and nominal ring width h � 2,5 mm (2,5), made
1 1
of martensitic steel (17 % Cr min.), subclass 66 (MC66), nitrided on the peripheral surface and side faces (NT), to a minimum
depth of 0,090 mm on the peripheral surface (090), and with an associated side face depth of a minimum of 0,020 mm:
Piston ring ISO 6624-3 KB- 90 ���� 2,5-MC66/NT090
10 © ISO 2001 – All rights reserved

---------------------- Page: 15 ----------------------
ISO 6624-3:2001(E)
4.7 Type KBA — Asymmetrical barrel faced keystone ring 15°
4.7.1 General features
See Table 2 for asymmetrical barrel dimensions. See Table 13 for dimensions and forces.
Dimensions in millimetres
Key
a
1 Reference plane Due to manufacturing processing, side angle tolerances are not cumulative.
b
2Mark Nominal.
Figure 7 — Type KBA
4.7.2 Designation
EXAMPLE Designation of a piston ring complying with the requirements of ISO 6624-3, being a steel, 15° keystone ring
with asymmetrical barrel faced peripheral surface (KBA), of nominal diameter d � 90 mm (90) and nominal ring width
1
h � 2,5 mm (2,5), made of martensitic steel (17 % Cr min.), subclass 66 (MC66), nitrided on the peripheral surface and side
1
faces (NT), to a depth of 0,070 mm min. on the peripheral surface (070), and with an associated side face depth of a minimum
of 0,020 mm:
Piston ring ISO 6624-3 KBA - 90 ���� 2,5-MC66/NT070
© ISO 2001 – All rights reserved 11

---------------------- Page: 16 ----------------------
ISO 6624-3:2001(E)
4.8 Type KM — Taper faced keystone ring 15°
4.8.1 General features
See Table 3 for taper. See Tabl
...