ISO 9018:2015

Overview

ISO 9018:2015 - "Destructive tests on welds in metallic materials - Tensile test on cruciform and lapped joints" defines how to prepare and carry out tensile (destructive) tests on welded cruciform and lapped joints with transverse-stressed fillet welds. The standard specifies test-piece and specimen sizes, preparation and marking, and the procedure for progressive tensile loading to determine tensile strength and the location of fracture in welded joints. It applies to metallic plates, sheets, extruded bars and other solid sections. Note: evaluation criteria for pass/fail are dealt with in the relevant application standard, not within ISO 9018 itself.

Key topics and technical requirements

• Scope and applicability: Cruciform and lapped joint specimens taken from plates, sheets or solid sections; transverse stressed fillet welds.
• Specimen geometry and marking: Detailed figures specify specimen layout, orientation (weld axis perpendicular to specimen length) and marking to identify extraction location.
• Preparation and extraction: Mechanical cutting (sawing or milling) is recommended; thermal cutting is allowed only if cuts are kept at least 8 mm from the specimen edge to avoid thermal alteration. Final surface finish by machining or grinding; avoid surface strain hardening, scratches or notches in the gauge length.
• Heat treatment and ageing: No heat treatment of the welded joint or specimen unless permitted by the relevant application standard; any heat treatment or ageing time (e.g., for aluminium) must be recorded.
• Test method and conditions: Progressive, continuous tensile loading in a direction perpendicular to the weld axis, carried out nominally at 23 °C ± 5 °C unless otherwise specified. General test principles of ISO 6892-1 apply.
• Measurements and post-test exam: Record maximum load (Fm), measure fracture area (Af) and average fracture width (wf), calculate tensile strength Rm = Fm/Af, record fracture location and any imperfections (including fish-eyes). If delamination occurs, the test is void.
• Reporting: ISO 9018 lists mandatory test-report items (reference to ISO 9018, date, examiner, specimen dimensions, misalignment, fracture location, imperfections, wf, Rm, load per unit length, test temperature, heat treatment details).

Applications and users

ISO 9018 is used by:

• Welding inspectors, QA/QC engineers and metallurgists for weld qualification, production testing and failure analysis
• Mechanical testing laboratories performing destructive weld tests
• Fabrication and manufacturing organizations preparing procedure qualification records and verifying fillet-weld performance
• Design and R&D teams assessing joint strength in plated structures

Keywords: ISO 9018:2015, tensile test, destructive tests on welds, cruciform joints, lapped joints, fillet weld testing, weld tensile strength, weld inspection.

Related standards

• ISO 6892-1 (referenced for general tensile test method and machine speed/controls)
• Relevant application and welding standards (used for acceptance criteria and procedure-specific requirements)