Overview
ISO 20623:2017 - "Petroleum and related products - Determination of the extreme‑pressure and anti‑wear properties of lubricants - Four‑ball method (European conditions)" defines standardized laboratory procedures to evaluate the extreme‑pressure (EP) and anti‑wear performance of liquid lubricants, lubricating greases and other consistent lubricants. The standard uses the widely‑used four‑ball machine to generate repeatable metrics (for research, development, quality control and fluid ranking) that feed into lubricant specifications. Test conditions are not intended to simulate specific service environments but to provide comparative, reproducible data.
Key topics and requirements
- Test scope: Applies to liquid lubricants (ISO 6743‑99 categories C, D, F, G, H, M, P), greases (ISO 6743‑9 category X) and consistent lubricants.
- Three test procedures:
- Test A - Load‑Wear Index (LWI): index of a lubricant’s ability to minimize wear (expressed in newtons).
- Test B - Wear‑load curve, Welding Load (WL) and Initial Seizure Load (ISL).
- Test C - Wear test for mean wear scar diameter (MWSD) at defined loads/durations.
- Measured properties: LWI, MWSD (mean wear scar diameter), WL (weld load), ISL (initial seizure load), wear‑load relationships.
- Apparatus & conditions:
- Four‑ball machine with one rotating ball against three fixed balls immersed in test fluid.
- Standard rotational speed: 1 450 r/min (European conditions), with loads applied from low (e.g., 60 N) up to several kilonewtons (machines commonly support up to 8 kN; some robust machines up to 12 kN).
- Cleaning solvents, ball specifications and preparation procedures are specified (see normative annexes).
- Friction recording devices are optional but, if used, must be calibrated per the manufacturer’s instructions.
- Purpose: Provides standardized data for R&D, formulation benchmarking, production quality control and inclusion in lubricant specifications.
Applications and users
- Who uses ISO 20623:2017:
- Lubricant manufacturers and formulators (product development and validation)
- Independent testing laboratories (conformance and comparative testing)
- OEMs and end‑users (component compatibility and supplier qualification)
- Quality managers and standards engineers (specification and batch control)
- Practical uses:
- Rank candidate lubricants for EP and wear performance
- Verify batch quality and stability over time
- Support troubleshooting of wear and seizure issues in components
- Provide data for procurement and specification clauses
Related standards
Keywords: ISO 20623:2017, four‑ball method, extreme‑pressure, anti‑wear, LWI, MWSD, weld load, initial seizure load, lubricant testing, four‑ball machine.