Overview - ISO 5173:2023 (Destructive tests on welds - Bend tests)
ISO 5173:2023 specifies standardized destructive bend tests on welds in metallic materials. It defines methods for making transverse root, face and side bend tests on specimens taken from butt welds, butt welds with cladding (clad plates and clad welds) and cladding without butt welds. The standard gives specimen dimensions, preparation and testing procedures intended to reveal surface or near-surface imperfections under tensile bending and to assess ductility of welded joints. ISO 5173:2023 applies to metallic products with welded joints made by any welding process.
Key topics and technical requirements
- Test types covered: Transverse face (TFBB), transverse root (TRBB), transverse side (TSBB), longitudinal face/root (LFBB/LRBB), cladding face/side tests with and without butt welds (FBC, SBC, FBCB, SBCB).
- Specimen preparation: Location, marking, heat treatment/aging, extraction and surface preparation. Specimens must be prepared without altering parent material or weld metal properties.
- Dimensions and geometry: Detailed specimen widths, thicknesses and edge radii for each test configuration are specified.
- Testing methods: Bending with a former (plunger/die), guided transverse bend tests using a roller, and bend testing with an additional backing plate. Alternative methods are specified when base material, heat‑affected zone or weld metal have significantly different mechanical properties.
- Test conditions and parameters: Etching, testing speed, temperature (to be recorded in the test report), diameter of former/roller, distance between rollers, bending angle and bending elongation.
- Results and reporting: Criteria for assessing imperfections and ductility, plus required test-report content (temperature, speed, specimen ID, etc.). An informative example report is included.
Practical applications - who uses ISO 5173:2023
ISO 5173 is used by:
- Welding engineers and fabricators for weld qualification and quality control
- Inspection and testing laboratories performing destructive weld testing
- Quality assurance teams in industries with welded assemblies (pressure vessels, pipelines, petrochemical, shipbuilding, power generation and general manufacturing)
- Standards committees and regulators specifying acceptance criteria for welded joints
The standard helps verify weld integrity, detect surface or near-surface defects, and confirm ductility performance across heterogeneous assemblies (including clad components).
Related standards and context
ISO 5173:2023 was prepared by ISO/TC 44 (Welding and allied processes) in collaboration with CEN/TC 121. It complements other ISO welding and nondestructive testing standards that govern weld procedure qualification, mechanical testing and inspection. For implementation, refer to your national standards body for any complementary normative requirements.