SIST EN ISO 8493:2004 PDF

Overview

EN ISO 8493:2004 (identical to ISO 8493:1998) specifies the drift-expanding (tube expansion) test for metallic tubes. The standard defines a method to determine the ability of circular-section tubes to undergo plastic deformation by forcing a conical mandrel through a tube end until a specified outside diameter is reached. It applies to tubes with outside diameters up to 150 mm (100 mm for light metals) and wall thicknesses up to 10 mm, unless a product standard specifies otherwise.

Keywords: EN ISO 8493:2004, ISO 8493, drift-expanding test, metallic tubes, tube ductility, conical mandrel.

Key topics and requirements

• Scope: Tests tube ductility/expansion capability for circular-section tubes (limits on diameter and thickness as above).
• Test principle: Expand the tube end by driving a conical mandrel until the target maximum outside diameter or specified relative expansion (%) is achieved.
• Equipment:
  • Variable-speed press or universal testing machine.
  • Polished, sufficiently hard conical mandrel; preferred cone angles are 30°, 45° and 60°.
  • Mandrel may include a groove for longitudinal weld flash on welded tubes.
• Test pieces:
  • Length depends on mandrel angle: when angle ≤ 30° use approx. L = 2·D; when angle > 30° use approx. L = 1.5·D.
  • Remaining cylindrical part after expansion must be at least 0.5·D. Ends should be perpendicular to tube axis; edges may be rounded or chamfered.
• Test conditions:
  • Ambient testing: 10 °C to 35 °C; controlled testing at 23 °C ± 5 °C.
  • Mandrel insertion without shock; mandrel must not rotate relative to the tube. Lubrication is permitted.
  • Dispute rate limit: mandrel penetration ≤ 50 mm/min.
• Acceptance criteria:
  • If product standard does not provide criteria, the test is passed if no visible cracks are observed without magnification. Slight edge cracking is not cause for rejection.
• Test report must include reference to ISO 8493, test-piece ID and dimensions, expanded maximum diameter or relative expansion, mandrel angle and the test result.

Applications and users

• Quality control and acceptance testing of steel, aluminium and other metallic tubes used in construction, hydraulic systems, heat exchangers and general engineering.
• Typical users: tube manufacturers, independent test laboratories, product standards committees, inspection and procurement engineers who need to verify tube ductility, forming performance and resistance to expansion-related cracking.

Related standards

• This European adoption EN ISO 8493:2004 supersedes EN 10234:1993.
• Prepared by ISO/TC 164 (Mechanical testing of metals) and adopted by CEN (ECISS/TC 29 - Steel tubes and fittings for steel tubes).

This summary gives practical guidance on what EN ISO 8493:2004 covers and how the drift-expanding test is specified and used in industry.