ISO 7905-4:2022

Overview

ISO 7905-4:2022 - Plain bearings - Bearing fatigue - Part 4 specifies a laboratory method to determine the endurance limit in fatigue for half-bearings made from a metallic multilayer bearing material. The standard defines specimen preparation, test setup, loading conditions, measurement procedures and result presentation for fatigue testing of ready-to-use half-bearings. It preserves residual manufacturing stresses and focuses on stresses in the crown area that typically govern fatigue life.

Key topics and technical requirements

• Test objective: determination of the fatigue endurance limit (σ_el) for half-bearings of metallic multilayer materials.
• Specimens: half-bearings ready for use; dimensions and layer thicknesses must be determined (microsection) after testing.
• Test principle and setup:
  • Specimens clamped at one end and loaded radially at the relief parting-line runout (cantilever-type load).
  • Load fluctuates between tension and compression; a mean tensile or compressive prestress may be applied to study mean-stress effects.
  • Frequency range: 50 Hz to 80 Hz.
  • Tests conducted in lubricant bath or in air at controlled temperature with tolerance ±2 °C.
• Measurements and calculations:
  • Nominal surface stress on bearing back measured by strain gauge or derived from radial force and cantilever beam theory.
  • Annex A provides stress-evaluation methods, dimensionless coefficients and worked examples for two- and three-layer systems.
  • Overlay stresses can be approximated via Young’s modulus ratios when overlay thickness is negligible.
• Crack detection and failure criteria:
  • Crack detection by dye penetrant in accordance with ISO 4386-3 or by microscopic inspection.
• Data presentation:
  • Endurance limit reported as σ-N (stress vs cycles) curves at specified temperature (±2 °C).
  • Typical termination for practical σ-N testing is 5 × 10^6 cycles; endurance limits can be quoted at specific cycles (e.g., 3×10^6, 10×10^6, 25×10^6, 50×10^6).
  • Statistical evaluation recommended due to scatter in fatigue results; Haigh diagrams (stress amplitude vs mean stress) suggested for additional presentation.

Applications

• Qualification and comparison of metallic multilayer plain bearing materials for automotive, industrial and heavy machinery plain bearings.
• Fatigue life assessment during bearing material development, quality control and failure analysis.
• Design validation where endurance limits of multilayer bearing linings are required for reliable plain-bearing systems.

Who should use this standard

• Bearing manufacturers and material suppliers
• Test laboratories and R&D teams in tribology and materials engineering
• OEMs and design engineers specifying bearing fatigue performance
• Quality assurance and certification bodies

Related standards

• ISO 4386-3 - Non-destructive penetrant testing (referenced for crack detection)
• ISO 7905-3 - Tests on plain strips of metallic multilayer bearing material
• ISO 3548-1, ISO 4378-1 - Related plain bearing design, materials and testing standards

Keywords: ISO 7905-4:2022, plain bearings, bearing fatigue, metallic multilayer bearing material, half-bearings, endurance limit, fatigue testing, σ-N curves.