Overview
EN ISO 7799:2000 - Metallic materials - Sheet and strip 3 mm thick or less - Reverse bend test specifies a laboratory method to determine the ability of thin metallic sheet and strip to undergo plastic deformation when subjected to alternating bending. The procedure (originally ISO 7799:1985) uses a rectangular test piece clamped at one end and repeatedly bent through 90° in alternating directions over a cylindrical support of specified radius. The standard applies to sheet and strip up to 3 mm thickness and can be applied to aluminium and its alloys only after prior agreement.
Key topics and requirements
- Scope: Evaluation of plastic deformation capacity for sheet and strip ≤ 3 mm thickness.
- Test principle: Repeated reverse bending (90°) in opposite directions to simulate cyclic bending strain.
- Specimen arrangement: Rectangular test piece held at one end (cantilever style).
- Bending support: Bending is performed over a cylindrical support with a specified radius (as defined in the standard).
- Materials covered: General metallic materials; aluminium and its alloys require specific agreement before application.
- Purpose of measurements: Determine suitability for forming processes and detect susceptibility to cracking or failure under alternating bend loads.
Note: The standard defines test geometry, support radius, and procedural parameters; consult the full EN ISO 7799:2000 text for exact dimensioning and acceptance criteria.
Applications
- Quality control and acceptance testing for sheet and strip materials used in forming and bending operations.
- Characterizing formability and bend fatigue resistance for manufacturing processes such as stamping, bending, and deep drawing.
- Comparative testing between production batches or suppliers to ensure consistent material performance.
- Material selection in product design where repeated or reverse bending is expected (e.g., flexible metal components, housings, brackets).
Who uses this standard
- Materials testing laboratories and metallurgical test houses.
- Manufacturers and processors of thin metallic sheets and strips (steel, stainless steel, other alloys).
- Quality assurance teams for automotive, appliance, aerospace and general metal fabrication industries.
- Procurement, R&D and engineering teams specifying mechanical testing and formability requirements.
Related standards
- ISO 7799:1985 (original international document)
- EN ISO 7799:2000 (European adoption)
- ICS classification: 77.040.10 - Mechanical testing of metals
Keywords: reverse bend test, EN ISO 7799:2000, ISO 7799, sheet and strip testing, metallic materials, formability test, aluminium alloys, mechanical testing, quality control.