Overview
ISO 1143:2021 - Metallic materials - Rotating bar bending fatigue testing specifies a standardized method for performing rotating bending (rotating bar) fatigue tests on metallic materials. Tests are performed with the specimen rotated and subjected to a constant bending moment in air at room or elevated temperature. The document defines specimen forms, test procedure, environmental and apparatus requirements, data presentation and measurement uncertainty. Note: notched specimen geometries are not standardized in ISO 1143, though the procedures can be applied to notched tests.
Keywords: ISO 1143:2021, rotating bar bending fatigue testing, metallic materials, rotating bending, fatigue testing, S‑N curve, fatigue life
Key topics and technical requirements
- Principle of test: constant bending moment on a rotated specimen; a stress cycle equals one full rotation.
- Specimen geometry: permitted forms include cylindrical (parallel), tapered and hourglass test sections; circular cross-sections are required. Loading configurations covered: cantilever (single- or two-point), beam (four-point).
- Specimen preparation: requirements for selection, marking, machining, heat treatment, surface condition, dimensional checks, storage and handling.
- Apparatus accuracy and verification: calibration and verification of bending moment and machine lever ratio; Annex A provides verification guidance.
- Test procedure: specimen mounting, application of force, frequency selection, test end criteria and elevated-temperature testing (heating device and temperature measurement).
- Data and reporting: required test report elements, tabular and graphical presentation (S‑N diagrams), and an example test report in Annex B.
- Measurement uncertainty: new Clause 13 addresses uncertainty in test conditions and results.
- Normative references: links to related standards covering calibration, axial fatigue methods, statistical analysis and vocabulary.
Practical applications and who uses it
ISO 1143:2021 is used by:
- Materials testing laboratories and fatigue test labs for producing repeatable S‑N data.
- Metallurgists and R&D teams assessing material fatigue properties and effects of heat treatment.
- Design and mechanical engineers for component life prediction and fatigue design validation.
- Quality and certification bodies requiring standardized fatigue test data for specifications and material acceptance.
Typical uses:
- Generating S‑N curves for alloys and steels.
- Comparing fatigue behavior across heat treatments or manufacturing processes.
- Evaluating elevated‑temperature fatigue performance for high‑temperature components.
- Supporting fatigue life assessments in automotive, aerospace, energy and heavy industry applications.
Related standards
- ISO 1099 - Fatigue testing (axial force-controlled)
- ISO 12106 - Fatigue testing (axial-strain-controlled)
- ISO 12107 - Statistical planning and analysis of fatigue data
- ISO 376 - Calibration of force-proving instruments
- ISO 23718 - Mechanical testing vocabulary
Using ISO 1143:2021 ensures reproducible rotating bending fatigue data that support reliable fatigue life assessment and material selection.
