ISO 6622-1:2021
(Main)Internal combustion engines — Piston rings — Part 1: Rectangular rings made of cast iron
Internal combustion engines — Piston rings — Part 1: Rectangular rings made of cast iron
This document specifies the essential dimensional features of rectangular rings made of cast iron, Types R, B, BA and M, having diameters up to and including 200 mm, used in reciprocating internal combustion piston engines. It is also applicable to piston rings of compressors working under similar conditions.
Moteurs à combustion interne — Segments de piston — Partie 1: Segments rectangulaires en fonte moulée
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 6622-1
Third edition
2021-08
Internal combustion engines — Piston
rings —
Part 1:
Rectangular rings made of cast iron
Moteurs à combustion interne — Segments de piston —
Partie 1: Segments rectangulaires en fonte moulée
Reference number
©
ISO 2021
© ISO 2021
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ii © ISO 2021 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Overview . 1
5 Ring types and designation examples . 1
5.1 Overview . 1
5.2 Type R — Straight faced rectangular ring . 1
5.2.1 General features. 1
5.2.2 Designation . 2
5.3 Type B — Barrel faced rectangular ring . 2
5.3.1 General features. 2
5.3.2 Designation . 3
5.4 Type BA — Asymmetrical barrel faced rectangular ring h ≥ 1,2 mm . 4
5.4.1 General features. 4
5.4.2 Designation . 5
5.5 Type M — Taper faced rectangular ring . 5
5.5.1 General features. 5
5.5.2 Designation . 6
6 Common features . 6
6.1 Face coating types . 6
6.2 Face shape types . 7
6.3 Piston ring twist features . 7
6.3.1 Taper faced rectangular ring with partly cylindrical machined (LM) or
lapped (LP) peripheral surface. 9
6.4 Chamfered edges . 9
6.5 Type R, B, BA and M rings (fully faced, semi-inlaid and inlaid) — Plating/coating
thickness .11
6.6 Type R, B, BA, and M rings — Nitrided case depth .12
7 Force factors .12
8 Dimensions .13
Bibliography .26
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
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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/d irectives).
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/p atents).
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iso/f oreword. html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 34,
Propulsion, powertrain and powertrain fluids.
This third edition cancels and replaces the second edition (ISO 6622-1:2003), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— figures were updated for a better understanding;
— added M6 taper in Table 3;
— added h dimension in Table 5;
— editorial adaptations according to ISO directives.
A list of all parts in the ISO 6622 series can be found on the ISO website.
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/m embers. html.
iv © ISO 2021 – All rights reserved
Introduction
The ISO 6622 series is one of a number of series of International Standards dealing with piston rings for
[2],[3],[4] [5] [6],[7], [8]
reciprocating internal combustion engines. Others are ISO 6621, ISO 6623, ISO 6624
[9], [10] [11],[12] [13]
, ISO 6625, ISO 6626 and ISO 6627 .
The common features and dimensional tables presented in this document constitute a broad range of
variables and, in selecting a particular ring type, it is important for the designer to bear in mind the
conditions under which it will be required to operate.
[3]
It is also important that the designer refers to the specifications and requirements of ISO 6621-3 and
ISO 6621-4 before completing selection.
INTERNATIONAL STANDARD ISO 6622-1:2021(E)
Internal combustion engines — Piston rings —
Part 1:
Rectangular rings made of cast iron
1 Scope
This document specifies the essential dimensional features of rectangular rings made of cast iron,
Types R, B, BA and M, having diameters up to and including 200 mm, used in reciprocating internal
combustion piston engines. It is also applicable to piston rings of compressors working under similar
conditions.
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 6621-1, Internal combustion engines — Piston rings — Part 1: Vocabulary
ISO 6621-4, Internal combustion engines — Piston rings — Part 4: General specifications
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 6621-1 apply.
ISO and IEC maintain terminological 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/
4 Overview
The rectangular ring types are specified in Tables 1 to 3 and Figures 1 to 4. Their common features and
the dimensions of those features are specified in Tables 4 to 10 and Figures 5 to 13. Tables 11 and 12
give the force factors for the different ring types, while Tables 13 and 14 give the dimensions and forces
of rectangular rings of radial wall thickness regular and thicker “D/22”, respectively.
5 Ring types and designation examples
5.1 Overview
The rectangular ring types are specified in Tables 1 to 3 and Figures 1 to 4.
5.2 Type R — Straight faced rectangular ring
5.2.1 General features
See Table 13 or 14 for dimensions and forces.
Key
1 reference plane
a
t = 0,005 × h .
Figure 1 — Type R
5.2.2 Designation
EXAMPLE Designation of a piston ring complying with the requirements of ISO 6622-1, being a rectangular
ring made of cast iron, with a straight faced peripheral surface (R), of nominal diameter d = 90 mm (90), of
nominal ring width h = 2,5 mm (2,5), made of non-heat treated grey cast iron, subclass 12 (MC12), phosphated
on all sides (PO):
Piston ring ISO 6622-1 R 90 × 2,5 - MC12/PO
5.3 Type B — Barrel faced rectangular ring
5.3.1 General features
See Table 13 or 14 for dimensions and forces.
2 © ISO 2021 – All rights reserved
Key
1 reference plane
a
See Table 1.
Figure 2 — Type B
Table 1 — Gauge width (h ) and barrel dimensions for symmetrical barrel faced compression
rings
Dimensions in millimetres
a b c
h h h h tolerance h t , t h
1 25 26 26 27 2 3 8
1,2 0,30 0,60 ±0,20 0,90 0,002.0,012 0,60
1,5 0,35 0,75 ±0,25 1,15 0,80
1,75 0,35 0,85 ±0,30 1,35 1,00
0,003.0,015
2,0 0,40 1,00 ±0,30 1,60 1,20
2,5 0,45 1,25 ±0,40 2,05 1,60
3,0 0,50 1,50 ±0,50 2,50 2,00
0,005.0,020
3,5 0,55 1,75 ±0,50 2,95 2,40
4,0 0,60 2,00 ±0,60 3,40 2,80
0,005.0,023
4,5 0,65 2,25 ±0,60 3,85 3,20
a
h may be lowered for rings with reduced edge dimensions.
b
t and/or t can be changed as agreed between edge dimensions.
2 3
c
Gauge width (h ) only informative; may be used only if agreed between manufacturer and client.
5.3.2 Designation
EXAMPLE Designation of a piston ring complying with the requirements of ISO 6622-1, being a rectangular
ring made of cast iron, with a barrel faced peripheral surface (B), of nominal diameter d = 90 mm (90), of nominal
width h = 2,5 mm (2,5), made of heat-treated martensitic spheroidal graphite cast iron, subclass 51 (
...
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