Overview - EN ISO 25239-2:2020 (Friction stir welding - Aluminium - Part 2)
EN ISO 25239-2:2020 specifies design requirements for friction stir weld joints in aluminium and aluminium alloys. Published by CEN and identical to ISO 25239-2:2020, it defines how welds should be documented, how joint geometry is selected, and what essential information must accompany welded assemblies. The standard applies to conventional friction stir welding (FSW) but explicitly excludes friction stir spot welding (covered by the ISO 18785 series). It supersedes the 2011 edition and incorporates updates such as consideration of half-overlap joints.
Key topics and technical requirements
- Scope and terminology: Uses definitions from ISO 25239-1 and ISO/TR 25901; the term “aluminium” covers alloys and tempers as specified by the designer.
- Documentation: Weld documentation must support the product’s end use. Drawings and records shall define weld requirements, essential process controls and reference welding procedure specifications (WPS). Weld symbols conform to ISO 2553.
- Joint design: Covers common joint types-butt, lap (including multi-sheet and half-overlap), T‑joints, corner and fillet joints, and circumferential butt joints. Joint selection must consider material properties and weld performance.
- Butt and lap joint requirements:
- Essential variables for butt joints must be defined in the WPS (per ISO 25239-4).
- For lap joints, the WPS shall specify the distance from the tool centreline to each sheet edge and distinguish FSW lap welds from other lap weld types.
- The standard highlights FSW asymmetry (advancing vs retreating side) and its impact on strength and load placement.
- Essential information: For each weld specify parent material (alloy, temper, form), pre-weld surface condition/coatings, weld location/tool path, finishing requirements, and postweld heat treatment.
- Dimensions and inspection: Final weldment dimensions on drawings must be final (no shrinkage allowances). Inspection methods and acceptance levels are to be defined and conform to ISO 25239-5.
Practical applications and who uses this standard
- Industries: Railway carriages, aerospace, marine vessels, food processing equipment, consumer products and other aluminium-structure fabrication where FSW is used.
- Users: Design and structural engineers, welding engineers, procedure writers, fabricators, quality/inspection personnel, and procurement/specification teams who need compliant joint designs and documented WPSs.
- Benefits: Ensures consistent joint performance, clear documentation for manufacturing and inspection, and safer, more reliable aluminium assemblies produced by FSW.
Related standards
Keywords: friction stir welding, FSW, aluminium, weld joint design, ISO 25239-2:2020, welding procedure specification, lap joints, butt joints, weld inspection.
