ISO 18669-2:2020

INTERNATIONAL ISO
STANDARD 18669-2
Second edition
2020-04
Internal combustion engines —
Piston pins —
Part 2:
Inspection measuring principles
Moteurs à combustion interne — Axes de pistons —
Partie 2: Principes de mesure pour le contrôle
Reference number
©
ISO 2020
© ISO 2020
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ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Measuring principles . 4
4.1 General measuring conditions . 4
4.2 Characteristics and measuring principles . 4
4.2.1 Outside diameter, d . .
1 4
4.2.2 Cylindricity of the outside diameter (d ). 5
4.2.3 Circularity of the outside diameter (d ) . 5
4.2.4 Circumferential waviness . 6
4.2.5 Edge drop-off, b, c .6
4.2.6 Inside diameter, d , d .
2 4 6
4.2.7 Concentricity of inside diameter (ID) relative to outside diameter (OD) . 6
4.2.8 Length, l .
1 7
4.2.9 Gauge length, l .
5 7
4.2.10 Runout of the end faces, s .8
4.2.11 End face concavity, h , and end face step, h .
1 2 8
4.2.12 End face diameter, d .
6 8
4.2.13 Outside-edge profile . 8
4.2.14 Inside chamfer, t .
1 9
4.2.15 Tapered bore diameter, d .
3 9
4.2.16 Tapered bore angle, α.9
4.2.17 Runout tapered bore, e .9
4.2.18 Roughness . 9
4.2.19 Carburised and nitrided case depth .10
4.2.20 Core hardness .10
4.2.21 Peripheral surface hardness .10
4.2.22 Volume change .11
4.2.23 Material defects.11
4.2.24 Residual magnetism .12
4.2.25 Visual defects .13
4.2.26 Grinder burn .13
4.2.27 Streaks on bore surface .13
Bibliography .14
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/ directives).
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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 34,
Propulsion, powertrain and powertrain fluids.
This second edition cancels and replaces the first edition (ISO 18669-2:2004), which has been
technically revised.
The main changes compared to the previous edition are as follows:
— the scope has been defined more in detail; and
— references have been updated.
A list of all parts in the ISO 18669 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/ members .html.
iv © ISO 2020 – All rights reserved

INTERNATIONAL STANDARD ISO 18669-2:2020(E)
Internal combustion engines — Piston pins —
Part 2:
Inspection measuring principles
1 Scope
This document defines the measuring principles used for measuring piston pins; it applies to piston
pins with a nominal outer diameter from 8 mm up to and including 100 mm, for reciprocating internal
combustion engines for road vehicles and other applications.
In certain applications, except road vehicles, and provided that mutual agreement is made between the
purchaser and the manufacturer, this document can be used with suitable modifications.
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 1302, Geometrical Product Specifications (GPS) — Indication of surface texture in technical product
documentation
ISO 18203, Steel — Determination of the thickness of surface-hardened layers
ISO 4287, Geometrical Product Specifications (GPS) — Surface texture: Profile method — Terms, definitions
and surface texture parameters
ISO 4288, Geometrical Product Specifications (GPS) — Surface texture: Profile method — Rules and
procedures for the assessment of surface texture
ISO 9934 (all parts), Non-destructive testing — Magnetic particle testing
ISO 6506 (all parts), Metallic materials — Brinell hardness test
ISO 6507 (all parts), Metallic materials — Vickers hardness test
ISO 6508 (all parts), Metallic materials — Rockwell hardness test
ISO 8015, Geometrical product specifications (GPS) — Fundamentals — Concepts, principles and rules
ISO 14104:2017, Gears — Surface temper etch inspection after grinding, chemical method
ISO 14253 (all parts), Geometrical product specifications (GPS) — Inspection by measurement of workpieces
and measuring equipment
ISO 15548 (all parts), Non-destructive testing — Equipment for eddy current examination
ISO 16810, Non-destructive testing — Ultrasonic testing — General principles
ISO 18265, Metallic materials — Conversion of hardness values
ISO 18669-1:2013, Internal combustion engines — Piston pins — Part 1: General specifications
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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 http:// www .electropedia .org/
3.1
outside diameter
d
diameter of the outer surface measured at any point excluding areas of edge drop-off (b) (3.5)
Note 1 to entry: See ISO 18669-1:2013, Figure 12.
3.2
cylindricity of the outside diameter
CYLt
peak-to-valley cylindricity deviation; geometric form of the peripheral surface excluding areas of edge
drop-off (b) (3.5)
Note 1 to entry: Characteristics measured in the axial direction are taper, convexity, concavity and waviness.
Note 2 to entry: See ISO 1101.
3.3
circularity of the outside diameter
RONt
peak-to-valley roundness deviation; deviations of the peripheral surface from circularity such as
waviness, ovality and spherical-triangular forms
Note 1 to entry: See ISO 1101.
3.4
circumferential waviness
undulations of the peripheral surface from circularity in a waveform
3.5
edge drop-off
b
c
geometric form of the peripheral surface at the outside edges
3.6
inside diameter
d
d
diameter of the bore measured at any point
3.7
concentricity of inside diameter relative to outside diameter
difference between the maximum and minimum dimensions of the wall thickness (a) as measured in a
plane perpendicular to the peripheral surface
Note 1 to entry: See ISO 1101.
3.8
length
l
Maximum dimension measured between two planes perpendicular to the peripheral surface.
2 © ISO 2020 – All rights reserved

3.9
gauge length
l
dimension between the gauge points measured perpendicular to the peripheral surface
3.10
runout of the end faces
axial distance between two circles located concentrically to the axis of the piston pin
Note 1 to entry: All points of the end face of the piston pin must lie during rotation around the axis.
3.11
end face diameter
d
maximum diameter of end face concavity or end face step
3.12
outside-edge profile
transition from the peripheral surface to the end face of piston pin
3.13
inside chamfer
t
transition from the inside cylindrical surface to the end face
3.14
tapered bore diameter
d
diameter of the taper at the end face
3.15
tapered bore angle
α
angle of inclination measured from the peripheral surface
3.16
runout tapered bore
e
concentricity of the tapered bore to the outside diameter (3.1)
3.17
carburised and nitrided case depth
thickness of the surface layer with a hardness value which is greater than the limit hardness Hs,
measured perpendicular to the piston pin peripheral surface or bore surface on the finish-machined
piston pin
3.18
core hardness
hardness in the core zone that is not affected by the case-hardened or the nitrided layer
3.19
peripheral surface hardness
hardness measured on the peripheral surface of the carburised or nitrided layer
3.20
volume change
change in volume detected as a permanent outside-diameter dimensional deviation at reference
temperature after being heated to a test temperature for a specified period of time
...