ISO 6622-2:2013

INTERNATIONAL ISO
STANDARD 6622-2
Second edition
2013-11-01
Internal combustion engines —
Piston rings —
Part 2:
Rectangular rings made of steel
Moteurs à combustion interne — Segments de piston —
Partie 2: Segments rectangulaires en acier
Reference number
©
ISO 2013
© ISO 2013
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ii © ISO 2013 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Overview . 1
4 Ring types and designation examples . 1
4.1 Type R — Straight-faced rectangular ring . 1
4.2 Type B — Barrel-faced rectangular ring . 2
4.3 Type BA — Asymmetrical barrel-faced rectangular ring, h ≥ 1,2mm . 4
4.4 Type M — Taper-faced rectangular ring . 5
5 Common features . 6
5.1 Type R — Straight-faced rectangular ring . 6
5.2 Type B — Barrel-faced rectangular ring . 7
5.3 Type BA — Asymmetrical barrel-faced rectangular ring, h ≥ 1,2 mm. 8
5.4 Type M — Taper-faced rectangular ring . 9
5.5 Type R, B, BA, and M rings (positive twist type) — Internal bevel top side . .11
5.6 Type M rings (negative twist type), taper M3 to M5 — Internal bevel bottom side .11
5.7 Type R, B, BA, and M rings — Outside and inside rounded edges .12
5.8 Type R, B, BA, and M rings (fully faced and inlaid) — Plating/coating thickness .12
5.9 Type R, B, BA, and M rings — Nitrided case depth .13
6 Force factors .14
7 Dimensions and forces .14
Bibliography .21
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. 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. 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.
The committee responsible for this document is ISO/TC 22, Road vehicles.
This second edition cancels and replaces the first edition (ISO 6622-2:2003), which has been
technically revised.
ISO 6622 consists of the following parts, under the general title Internal combustion engines — Piston rings:
— Part 1: Rectangular rings made of cast iron
— Part 2: Regular rings made of steel
iv © ISO 2013 – All rights reserved

Introduction
The ISO 6622 series is one of a number of series of International Standards dealing with piston
[2] [3] [4] [5] [6]
rings for reciprocating internal combustion engines. Others are ISO 6621, ISO 6623,
[7] [8] [9] [10] [12] [13] [14] [15]
ISO 6624,  ISO 6625, ISO 6626, and ISO 6627 (see Bibliography for details).
The common features and dimensional tables presented in this part of ISO 6622 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]
It is also essential that the designer refer to the specifications and requirements of ISO 6621-3 and
[16]
ISO 6621-4 before completing his selection.
INTERNATIONAL STANDARD ISO 6622-2:2013(E)
Internal combustion engines — Piston rings —
Part 2:
Rectangular rings made of steel
1 Scope
This part of ISO 6622 specifies the essential dimensional features of rectangular rings made of steel,
types R, B, BA, and M having nominal diameters from 30 mm up to and including 160 mm, used in
reciprocating internal combustion piston engines for road vehicles and other applications.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
Not applicable.
3 Overview
The rectangular ring types are specified in Tables 1 to 5 and Figures 1 to 6. Their common features and
the dimensions of those features are specified in Tables 6 to 11 and Figures 7 to 22. Tables 12 and 13
give the force factors for the different ring types, while Table 13 gives the dimensions and forces of the
rectangular rings.
4 Ring types and designation examples
4.1 Type R — Straight-faced rectangular ring
4.1.1 General features
Figure 1 shows the general features of piston ring type R.
See Table 13 for dimensions and forces.
Key
1 reference plane
a
t = 0,005 × h .
Figure 1 — Type R
4.1.2 Designation
EXAMPLE Designation of a piston ring complying with the requirements of this part of ISO 6622 (i.e.
ISO 6622-2) being a steel, rectangular ring with a straight-faced peripheral surface (R), of nominal diameter
d = 60 mm (60), of nominal ring width h = 1,2 mm (1,2), made of CrSi alloyed steel, subclass 62 (MC62), and with
1 1
a chromium-plated peripheral surface of a minimum thickness 0,1 mm (CR2). Parameters in parenthesis are used
in the ISO ring designation:
Piston ring ISO 6622-2 R - 60 × 1,2 - MC62/CR2
4.2 Type B — Barrel-faced rectangular ring
4.2.1 General features
See Table 13 for dimensions and forces.
2 © ISO 2013 – All rights reserved

Key
1 reference plane
Figure 2 — Type B
Table 1 — Symmetrical barrel dimensions and gauge width (h )
Dimensions in millimetres
a
h h h h tol. h t , t h
1 25 26 26 27 2 3 8
0,8 0,20 0,40 ± 0,15 0,60 0,001.0,010 0,40
1,0 0,25 0,50 ± 0,15 0,75 0,001.0,011 0,50
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
a
Gauge width (h ) only informative; may be used only if agreed between manufacturer and customer.
4.2.2 Designation
EXAMPLE Designation of a piston ring complying with the requirements of this part of ISO 6622 (i.e. ISO 6622-2)
being a steel, rectangular ring with a barrel-faced peripheral surface (B), of nominal diameter d = 60 mm (60),
of nominal ring width h = 1,5 mm (1,5), made of martensitic steel (17 % Cr), subclass 66 (MC66), nitrided on the
peripheral surface and side faces (NT), to a depth of 0,03 mm min. on the peripheral surface (030), and with an
associated side face depth of 0,010 mm min. Parameters in parenthesis are used in the ISO ring designation:
Piston ring ISO 6622-2 B - 60 × 1,5 - MC66/NT030
4.3 Type BA — Asymmetrical barrel-faced rectangular ring, h ≥ 1,2mm
4.3.1 General features
See Table 13 for dimensions and forces.
Key
1 reference plane
2 top side identification mark
Figure 3 — Type BA
Table 2 — Asymmetrical barrel dimensions
Dimensions in millimetres
a b b
h h h h tol. h t t
1 25 26 26 27 2 3
c c c
0,20 0,35 0,80
1,2 ± 0,15 0.0,005 0,005.0,016
0,28 0,43 0,90
1,5 0,35 0,50 ± 0,15 1,15 0…0,006 0,007…0,022
1,75 0,35 0,55 1,35 0,008…0,025
± 0,20 0…0,007
2,0 0,40 0,60 1,50 0,009…0,030
2,5 0,45 0,70 1,80 0,011…0,035
± 0,25 0…0,008
3,0 0,55 0,80 2,10 0,012…0,038
3,5 0,60 0,90 ± 0,30 2,40 0…0,009 0,012…0,040
a
h may be lowered for rings with reduced edge dimensions.
b
t and/or t may be varied as agreed between manufacturer and customer.
2 3
c
Recommended for bottom edge smaller than 0,2 mm.
4 © ISO 2013 – All rights reserved

4.3.2 Designation
EXAMPLE Designation of a piston ring complying with the requirements of this part of ISO 6622 (i.e.
ISO 6622-2) being a steel, rectangular ring with an asymmetrical barrel-faced peripheral surface (BA), of nominal
diameter d = 80 mm (80), of nominal ring width h = 1,5 mm (1,5), made of martensitic steel (17 % Cr), subclass
1 1
66 (MC66), nitrided on the peripheral surface and side faces (NT) to a depth of 0,05 mm min. on the peripheral
surface (050), and with an associated side face depth of 0,015 mm min. Parameters in parenthesis are used in the
ISO ring designation:
Piston ring ISO 6622-2 BA - 80 × 1,5 - MC66/NT050
4.4 Type M — Taper-faced rectangular ring
NOTE Taper M1 excluded.
4.4.1 General features
See Table 13 for dimensions and forces.
Key
1 reference plane
2 top side identification mark
Figure 4 — Type M
Table 3 — Taper
Dimensions in millimetres
c
Nitrided rings and chromium-plated or spray-coated rings with peripheral surface ground
a a d
Code with IF (top side) with IFU (bottom side)
Taper Tolerance
b
Taper Tolerance Taper Tolerance
M2 30 30 — —
M3 60 60 60
+60 +60
0 0
+60
M4 90 90 90
M5 120 120 120
a
IF and IFU are explained in Figures 24 and 25.
b
For M rings (negative twist type) M3, M4, and M5, the twist angle should not exceed 90 % of the minimum taper angle.
c
For chromium plated rings with tapered peripheral surface not ground, the tolerance shall be increased by 10 (e.g.
+60 +70
M3 = 60: for M rings or for M rings with IF or IFU).
0 0
d
IFU not recommended for rings with h ≤ 1,2 mm.
4.4.2 Designation
EXAMPLE Designation of a piston ring complying with the requirements of this part of ISO 6622 (i.e.
ISO 6622-2) being a steel, rectangular ring with 60′ taper-faced peripheral surface (M3), of nominal diameter
d = 60 mm (60), of nominal ring width h = 1,5 mm (1,5), made of alloyed steel (CrSi), subclass 62 (MC62), with
1 1
a chromium-plated peripheral surface of a minimum thickness of 0,1 mm (CR2). Parameters in parenthesis are
used in the ISO ring designation:
Piston ring ISO 6622-2 M3 - 60 × 1,5 - MC62/CR2
5 Common features
5.1 Type R — Straight-faced rectangular rin
...