ISO 8535-2:2003

INTERNATIONAL ISO
STANDARD 8535-2
Second edition
2003-10-01
Compression-ignition engines — Steel
tubes for high-pressure fuel injection
pipes —
Part 2:
Requirements for composite tubes
Moteurs à allumage par compression — Tubes en acier pour lignes
d'injection à haute pression —
Partie 2: Caractéristiques des tubes composites

Reference number
©
ISO 2003
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ii © ISO 2003 — All rights reserved

Contents Page
Foreword. iv
1 Scope. 1
2 Normative references . 1
3 Dimensions and tolerances . 1
4 Material processing . 3
5 Testing. 5
6 Designation. 7
7 Identification and marking . 8
8 Packing. 8
Bibliography . 9

Foreword
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(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
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established has the right to be represented on that committee. International organizations, governmental and
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ISO 8535-2 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 7, Injection
equipment and filters for use on road vehicles.
This second edition cancels and replaces the first edition (ISO 8535-2:1993), which has been technically
revised.
ISO 8535 consists of the following parts, under the general title Compression-ignition engines — Steel tubes
for high-pressure fuel injection pipes:
 Part 1: Requirements for seamless cold-drawn single-wall tubes
 Part 2: Requirements for composite tubes

iv © ISO 2003 — All rights reserved

INTERNATIONAL STANDARD ISO 8535-2:2003(E)

Compression-ignition engines — Steel tubes for high-pressure
fuel injection pipes —
Part 2:
Requirements for composite tubes
1 Scope
This part of ISO 8535 specifies the dimensions of, and gives requirements for, composite steel tubes for high-
pressure fuel injection pipes used on diesel (compression-ignition) engines (Class 2) and for fuel injection
pump testing (Class 1).
2 Normative references
The following referenced documents are indispensable for the application 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 404, Steel and steel products — General technical delivery requirements
ISO 6507-1, Metallic materials — Vickers hardness test — Part 1: Test method
ISO 6892, Metallic materials — Tensile testing
3 Dimensions and tolerances
3.1 Diameters
Recommended inside and outside diameters are given in Table 1. Other sizes may be used by agreement
between supplier and purchaser.
Tolerances on inside and outside diameters shall be as follows.
a) Inside diameter, d
± 0,05 mm for Class 2
1)
± 0,025 mm for Class 1
b) Outside diameter, D
± 0,06 mm for Classes 1 and 2
1) Tolerance in accordance with ISO 4093.
c) Concentricity of the tube outside diameter relative to the inside diameter shall be proportional to the wall
thickness, as shown in Figure 1.
3.2 Length
Length and tolerances on length shall be by agreement between supplier and purchaser.
Table 1 — Recommended inside and outside diameters
Dimensions in millimetres
a b
Inside diameter fin Outside diameter fin
d D
Preferred Non-preferred 4,5 6 7
1,12
1,25
1,4
1,5
1,6
1,7
1,8
1,9
2,12
2,24
2,36
2,5
2,65
2,8
3,15
3,35
NOTE The diameter sizes have been established with the ratio of outside to inside diameter within the range of 2 to 4.
a
Based on ISO 3.
b
Size combinations to be used are those falling within the cross-hatched region.

2 © ISO 2003 — All rights reserved

Figure 1 — Tube diameters
4 Material processing
4.1 Steel manufacturing process
The tubes shall be manufactured from an unalloyed quality steel or an equivalent quality steel produced by a
steel-making process that ensures a very homogeneous structure.
The composite structure can be produced in various ways:
 a seamless inner (liner) tube is indicated by “CA”;
 a seamed inner tube is indicated by “CB”.
4.2 Surface quality
4.2.1 General
The outside and inside surfaces of finished tubes shall be free from scale, rust, grooves, laps, laminations,
deep pits or other injurious defects.
4.2.2 Minimum surface quality of bore (Grade S)
The inside of the tubes of bore Grade S shall be finished to ensure a smooth bore of accurate size with no
more than five imperfections (fissures, crevices, etc.) over 0,08 mm to 0,13 mm maximum depth per tube
cross-section, using 50× magnification for examination (see Table 2). This does not apply to tube type CB.
4.2.3 Higher surface quality of bore (Grades O, P, Q and R)
If closer control over the depth of imperfections is required, bore grades O, P, Q or R, assessed under the
magnification indicated (see Table 2), may be specified in the tube designation (see Clause 6). This does not
apply to tube type CB.
Table 2 — Bore grade
...