ISO 7905-3:2019

Overview

ISO 7905-3:2019 specifies a laboratory method to determine the endurance limit in fatigue of plain strips made from metallic multilayer bearing materials. The standard covers specimen preparation, a cyclic bending test procedure that reproduces tension–compression loading over the running surface, and evaluation and presentation of fatigue results. The method also allows assessment of the influence of hydraulic pressure and variable temperature on fatigue performance.

Key topics and technical requirements

• Test specimens: flat thin rectangular strips with chamfered edges and a contoured test section; layer thickness and surface texture must be representative of the actual manufacturing sequence and finishing.
• Test principle: cantilever-style clamping at one end with cyclic loading at the free end producing bending from tension to compression; optional tensile or compressive prestress to study mean-stress effects.
• Environment: tests performed in lubricant-filled chambers or in air at controlled temperatures (±2 °C).
• Instrumentation and control:
  • Bending stress measured by a strain gauge near the clamp on the specimen back.
  • Load amplitude controlled by force or displacement; test frequency range 50–80 Hz.
  • Crack detection by dye penetrant or microscope.
• Result presentation and evaluation:
  • Endurance limits presented as σ–N (stress vs. cycles) curves and optionally as Haigh diagrams (stress amplitude vs mean stress).
  • Typical termination and endurance points may be quoted at specified cycle counts (e.g., 3×10^6, 10×10^6, 25×10^6, 50×10^6 cycles); statistical methods recommended to address scatter.
  • Metallographic examination to identify damage mechanisms, corrosion, and thermal diffusion effects.
• Limitations: the method does not capture residual stresses introduced by some bearing manufacturing processes.

Applications and practical value

ISO 7905-3 is used to:

• Assess fatigue performance and endurance limits of multilayer plain bearing linings.
• Compare bearing material formulations, layer sequences and surface finishes under controlled cyclic loading.
• Investigate effects of temperature, hydraulic pressure, and mean stress on bearing fatigue life.
• Support material selection, quality control, failure analysis, and R&D for plain bearing systems.

Keywords: ISO 7905-3, plain bearings, bearing fatigue, multilayer bearing material, endurance limit, fatigue testing, strain gauge, σ–N curve, Haigh diagram.

Who should use this standard

• Bearing manufacturers and material suppliers
• Test laboratories and quality-control engineers
• Design engineers in automotive, industrial machinery, hydraulic system and rotating equipment sectors
• R&D teams evaluating new bearing linings and treatments

Related standards

• ISO 3548-1 - Plain bearings - Thin-walled half bearings: tolerances, design features and test methods
• ISO 4378-1 - Plain bearings - Terms, definitions, classification and symbols (design and material properties)