Overview - ISO 8494:2013 (Flanging test for metallic tubes)
ISO 8494:2013 specifies a standardized flanging test method to determine the ability of metallic tubes (circular cross-section) to undergo plastic deformation during flange formation. The standard applies to tubes with an outside diameter up to 150 mm and wall thickness up to 10 mm, unless a relevant product standard narrows that range. ISO 8494 is part of the mechanical testing family for metallic materials and was prepared by ISO/TC 164 (Ductility testing).
Key topics and technical requirements
- Scope and purpose: Assess tube ductility during end-flange formation by mechanically expanding a tube end until a prescribed flange diameter is reached.
- Test specimen:
- Length ~ 1.5 × original outside diameter (D); remaining cylindrical length after flanging ≥ 0.5 × D.
- Ends machined perpendicular to tube axis; edges may be rounded or chamfered.
- Internal weld flash may be removed for welded tubes.
- Testing equipment:
- Variable-speed press or universal testing machine.
- Polished, hardened forming tools: a conical mandrel (commonly 90°), a flanging tool (cylindrical end ≈ 1 mm less than tube ID, plus a flat concentric portion at least the required flange diameter) and optional supporting die.
- Procedure highlights:
- Test temperature normally ambient (10 °C to 35 °C); controlled testing at 23 °C ± 5 °C.
- Preform by forcing the conical mandrel to drift the tube, then form the flange with the flanging tool to reach the specified maximum flange diameter (D_u).
- Mandrel may be lubricated and must not rotate relative to the test piece.
- In dispute cases, forming tool speed ≤ 50 mm/min.
- Acceptance/interpretation:
- Follow the relevant product standard for pass/fail criteria. If none is specified, the test piece passes if no visible cracks are detected without magnification; slight edge cracking is not cause for rejection.
- Test report must include reference to ISO 8494, specimen identification and dimensions, maximum flange diameter or relative expansion, corner radius R (if relevant), and the test result.
Applications and users
- Used by tube manufacturers, metallurgical and mechanical testing laboratories, and product standards committees to validate formability and quality control of tubes intended for flanged connections.
- Typical industries: automotive, hydraulic and pneumatic systems, heat exchangers, plumbing and HVAC components where reliable tube flanges are required.
- Useful for design, procurement, and certification activities that need objective, repeatable tube flanging performance data.
Related standards and context
- Part of ISO/TC 164 mechanical testing of metals, Subcommittee SC 2 (Ductility testing).
- Test details (e.g., exact flange diameter, radii, and acceptance criteria) are often specified in the relevant product standard for the tube material or application.