Overview - EN ISO 9018:2015 (Tensile test on cruciform and lapped joints)
EN ISO 9018:2015 specifies how to perform destructive tensile tests on welded cruciform and lapped joints in metallic materials, with focus on transverse‑stressed fillet welds. The standard defines test‑piece and specimen sizes, the tensile test procedure, and required measurements to determine tensile strength and the location of fractures in welded joints. It is published by CEN as the European adoption of ISO 9018:2015 and supersedes EN ISO 9018:2003.
Key topics and technical requirements
- Scope: Applicable to plates, sheets, extruded bars and other solid sections joined by cruciform or lapped welds.
- Test environment: Default test temperature is 23 °C ± 5 °C; general tensile test principles of ISO 6892-1 apply.
- Specimen geometry and marking: Sizes and dimensions for cruciform and lapped specimens are defined; the weld axis must be perpendicular to specimen length and each specimen must be uniquely marked (including, where required, working direction).
- Preparation and extraction: Mechanical cutting (sawing/milling) is required for steel; if thermal cutting is used, cuts must be at least 8 mm from the specimen edge. Final surface preparation must avoid strain hardening or overheating and must be free from transverse scratches or notches in the gauge length.
- Heat treatment and ageing: No heat treatment shall be applied unless a relevant application standard permits it; any heat treatment or natural ageing (e.g., aluminium alloys) must be recorded.
- Test procedure: Load is applied gradually and continuously perpendicular to the weld axis until rupture, with uniform loading speed (per ISO 6892-1).
- Measurements and reporting: Record test temperature, maximum load, fracture area and calculate tensile strength (R = Fm / Af). Measure average fracture width by several measurements across the fracture (spacing about 3×a). Report imperfections (type, size, location) - e.g., fish eyes - and note any delamination (which voids the test).
- Limits: Note that this standard does not include guidance for the evaluation of test results (acceptance criteria are in relevant application or product standards).
Practical applications and users
EN ISO 9018:2015 is intended for:
- Welding engineers and laboratory technicians conducting destructive qualification tests.
- Quality control teams verifying weld integrity in production and procedure qualification.
- Manufacturers of welded components (pressure vessels, structural fabrications, transport, aerospace subcomponents).
- Inspection bodies and third‑party testing laboratories performing reproducible tensile testing of fillet welds.
- R&D and failure analysis where tensile strength and fracture location of welded joints must be established.
Keywords: EN ISO 9018:2015, tensile test, cruciform joints, lapped joints, destructive tests, fillet welds, welded joints, tensile strength, test specimens.
Related standards
- ISO 6892-1 - Metallic materials - Tensile testing - Part 1: Method of test at room temperature (normative reference).
- EN ISO 9018:2003 - previous edition (superseded).