EN ISO 8496:2013 PDF

Overview

EN ISO 8496:2013 (ISO 8496:2013) defines the ring tensile test for metallic tubes. The standard specifies a method to subject a ring cut from a tube to circumferential strain until fracture, with the primary purpose of revealing surface and internal defects and, where appropriate, assessing tube ductility. This European adoption by CEN is published as EN ISO 8496:2013 and supersedes the 2004 edition.

Key topics and technical requirements

• Scope and applicability
  • Applicable to tubes with outside diameter > 150 mm, wall thickness ≤ 40 mm and inside diameter > 100 mm.
• Test principle
  • A ring cut from the tube is strained in the circumferential direction until fracture occurs.
• Apparatus
  • Two circular pins of equal diameter with parallel axes; pins move apart while remaining parallel.
  • Pin diameter should be the minimum permitted by strength but, where inside diameter allows, at least 3× the wall thickness of the tube.
• Test piece preparation
  • Ring end faces perpendicular to tube axis.
  • Typical ring width ≈ 15 mm; if wall thickness > 15 mm, ring length may equal thickness.
  • Ends must be free of burrs; edges may be rounded or chamfered.
• Procedure and conditions
  • General ambient test temperature: 10 °C to 35 °C. Controlled tests: 23 °C ± 5 °C.
  • Strain the ring by moving pins apart at a specified rate; in disputes the rate shall not exceed 5 mm/s.
• Interpretation
  • Follow the relevant product standard for acceptance criteria. If unspecified, a test passes when expected fracture behavior occurs and no other cracks are visible without magnification.
• Test report minimum contents
  • Reference to ISO 8496, identification and dimensions of test piece, and test result.

Practical applications

• Detecting surface and internal defects (e.g., laps, seams, micro-cracks) in large-diameter tubes.
• Assessing ductility and fracture behavior of metallic tubes used in pipelines, pressure equipment, structural components, and industrial tubing where circumferential integrity is critical.
• Quality control and lot acceptance testing in tube manufacturing, finishing, and incoming inspection.

Who uses this standard

• Metallurgical and mechanical testing laboratories performing tube mechanical tests.
• Tube manufacturers, quality assurance engineers, and inspection bodies.
• Designers and specifiers who require validated tube ductility and defect-detection methods for large-diameter tubes.

Related and administrative notes

• Prepared by ISO/TC 164 (Mechanical testing of metals), with involvement from ECISS/TC 110.
• This edition (2013) is a minor revision of earlier editions and is adopted in Europe as EN ISO 8496:2013.
• For interpretation and acceptance criteria always refer to the relevant product standard specified by the purchaser or regulatory framework.