Overview
EN ISO 25239-1:2020 - Friction stir welding - Aluminium - Part 1: Vocabulary is the ISO/CEN vocabulary standard that defines terms and definitions used for friction stir welding (FSW) of aluminium and its alloys. Published as an endorsed European Standard by CEN in July 2020, this second edition updates the earlier edition and clarifies FSW terminology to support consistent communication, specification and quality control across industry, research and standards work.
Key Topics
This part of the ISO 25239 series focuses exclusively on vocabulary and covers terminology that underpins process specification, testing and inspection for FSW of aluminium. Important technical terms and concepts included (examples drawn from the standard) are:
- Core process terms: friction stir welding (FSW), advancing side, retreating side, axial force, plunge phase, dwell time (start and end), exit hole.
- Tool and tooling terms: adjustable tool probe, fixed probe, bobbin tool, stationary shoulder tool.
- Weld geometry and defects: faying surface, hook, heel, heel plunge depth, joint area deformation, root flaw.
- Process control and roles: force control, temperature control, operator (role definition), multiple spindles.
- Normative linkages: references ISO/TR 25901 (welding vocabulary) and aligns with other parts of the ISO 25239 series.
The 2020 edition added definitions such as joint area deformation, operator, plunge phase, root flaw, stationary shoulder tool, and temperature control, and removed some earlier terms (e.g., incomplete penetration, multi run welding).
Applications
EN ISO 25239-1:2020 is a foundational reference for any organization engaged in friction stir welding of aluminium. Typical users include:
- Welding engineers and process developers standardizing FSW terminology for specifications and procedures.
- Quality managers and inspectors writing acceptance criteria and defect descriptions.
- Manufacturers and fabricators in sectors using FSW: railway carriages, consumer products, food processing equipment, aerospace structures and marine vessels.
- Certification bodies, test houses and researchers ensuring consistent use of terms across reports, standards and technical documentation.
Using a common vocabulary reduces miscommunication, supports contract clarity, and assists in training and operator competence frameworks.
Related Standards
- ISO 25239 series (other parts cover requirements, operator/welder qualification and testing) - see the ISO website for the full list.
- ISO/TR 25901 (Welding and allied processes - Vocabulary) is a normative reference used to harmonize general welding terminology.
Keywords: EN ISO 25239-1:2020, friction stir welding, FSW terminology, aluminium welding, welding standards, CEN, ISO 25239.