ISO 8535-2:2003

Overview

ISO 8535-2:2003 defines requirements for composite steel tubes used in high‑pressure fuel injection pipes for diesel (compression‑ignition) engines (Class 2) and for fuel injection pump testing (Class 1). The standard covers tube dimensions, material processing, surface finish, mechanical properties, testing, designation, marking and packing to ensure reliable performance in fuel injection systems.

Key Topics

• Dimensions & tolerances
  • Recommended inside/outside diameters with preferred size ranges; concentricity specified proportional to wall thickness.
  • Inside diameter tolerances: ±0.05 mm (Class 2) and ±0.025 mm (Class 1). Outside diameter tolerance: ±0.06 mm.
• Material & composite structure
  • Tubes manufactured from unalloyed or equivalent homogeneous steel.
  • Composite types: CA (seamless inner liner) and CB (seamed inner tube).
• Surface quality & bore grades
  • Inside bore cleanliness and surface imperfection limits by bore grades S, R, Q, P, O, with specified magnifications for inspection (50× to 500×) and maximum permissible defect depths.
  • Outside surface finish codes (e.g., as‑processed, zinc electroplated with chromating) and corrosion protection guidance.
• Mechanical properties
  • Minimum tensile strength, yield stress, elongation and hardness specified per tube type (e.g., Rm 310 N/mm², ReH 205 N/mm²; differing A5 and hardness values for CA vs CB).
• Testing & acceptance
  • Lot testing, dimensional checks, tensile/hardness testing (ISO 6892, ISO 6507‑1), bending (180° around rod of same diameter), cold upsetting (compress 2D to D without cracks >0.13 mm) and inside pressure (hydraulic or agreed NDT).
  • Retest and lot rejection rules; optional manufacturer test certificate (designation may include “Z”).
• Designation, marking & packing
  • Standardized designation format (tube, part reference, type CA/CB, size, class, mechanical code, bore grade, surface finish, optional “Z”).
  • Identification by labels; delivery in sealed bundles unless otherwise agreed.

Applications

ISO 8535-2 is used by:

• OEMs and engine manufacturers specifying fuel-line components for diesel engines.
• Tube and component manufacturers producing high‑pressure injection pipes and liners.
• Quality inspectors and test laboratories conducting mechanical, metallographic and pressure testing.
• Purchasing and procurement teams setting acceptance criteria and certificates for fuel injection pipe supplies. Practical uses include fuel injection system assembly, pump test lines, and any application requiring robust, corrosion‑resistant, high‑pressure fuel tubing.

Related Standards

• ISO 8535‑1 (seamless single‑wall tubes)
• ISO 404 (delivery requirements)
• ISO 6892 (tensile testing)
• ISO 6507‑1 (Vickers hardness test)
• ISO 4093 (high‑pressure pipes for pump testing)
• ISO 2080 / ISO 4520 (electroplating & chromate conversion coatings)

Keywords: ISO 8535-2, compression-ignition engines, steel tubes, high-pressure fuel injection pipes, composite tubes, diesel engines, bore grades, tube testing, mechanical properties.