Overview
ISO/TR 14345:2012 - Fatigue testing of welded components - Guidance provides best-practice guidance for laboratory fatigue testing of welded metallic components in the medium- and high-cycle regimes. It covers both constant- and variable-amplitude loading where nominal stresses do not exceed yield. The Technical Report addresses specimen design and manufacture, testing procedures and plans, fatigue testing and post‑mortem examination, and the presentation and statistical evaluation of results. It does not cover corrosion fatigue, high‑temperature fatigue, or specifically low‑cycle strain‑controlled testing (though the same specimens can sometimes be used).
Key topics and technical requirements
- Scope of testing: Guidance for medium- and high-cycle fatigue under constant- or variable-amplitude loading; nominal stresses below yield.
- Specimen design and manufacture: Guidance to make test specimens representative of real welded joints (material, thickness, weld detail, weld procedure, residual stress considerations, and extraction of multiple specimens from panels).
- Loading and fixture considerations: Recommendations to ensure failure occurs at the weld detail of interest (axial vs bending loading, use of waisted specimens, avoiding grip or load-point notching).
- Welding procedure control: Record and replicate relevant welding parameters (process, position, preheat, sequence, start/stops) to ensure realistic residual stresses and weld geometry.
- Testing procedures and plan: Advice on constant- and variable-amplitude test sequences, failure criteria, and avoiding biased results when combining data from different sources.
- Post-mortem examination: Guidance on fractography and weld profile measurement to confirm failure modes and locate initiation sites (Annex A covers weld profile measurement).
- Presentation and statistics: Reporting formats (Annex B includes an example fatigue data sheet) and statistical analysis methods for S–N data and pooled results.
Practical applications and who uses it
ISO/TR 14345 is intended for:
- Welding engineers and fabricators validating joint quality and welding procedures.
- Fatigue test laboratories developing representative specimen programs and test plans.
- Structural and design engineers producing or validating S–N curves and fatigue life predictions for welded details.
- Quality assurance and R&D teams comparing data across workshops or test facilities and producing reliable design fatigue curves.
Typical uses include generating S–N data for design, validating special or non-standard details, comparing lab results from different sources, and informing fatigue design rules.
Related standards
- IIW guidance and fatigue design codes referenced in the report (for large-scale testing, variable-amplitude loading guidance, and statistical evaluation).
- Standards and codes on welding procedure qualification and mechanical testing, where applicable.
Keywords: ISO/TR 14345, fatigue testing, welded components, welded joints, S–N curves, variable-amplitude loading, specimen design, fatigue data, weld profile, post-mortem examination.