Overview
EN ISO 20623:2018 (ISO 20623:2017) - titled "Petroleum and related products - Determination of the extreme‑pressure and anti‑wear properties of lubricants - Four‑ball method (European conditions)" - is a harmonized European adoption of the ISO test method for evaluating lubricant extreme‑pressure (EP) and anti‑wear performance using the four‑ball machine. This second edition supersedes the 2003 version and expands applicability to all types of liquid lubricants and greases. The standard defines test principles, apparatus requirements, test procedures, calculations and reporting for reproducible four‑ball method testing.
Key Topics
- Principle: A rotating ball pressed against three stationary balls immersed in lubricant to assess wear and seizure under defined load, time and speed conditions.
- Standardized conditions: Harmonizes results by specifying European test conditions including a single rotational speed of 1 450 r/min to reduce variation between countries and machine types.
- Test procedures: Defines three main test types:
- Test A - Load‑Wear Index (LWI)
- Test B - Wear‑load curve, Welding Load (WL) and Initial Seizure Load (ISL)
- Test C - Wear test (short and long duration modes)
- Measured properties: Initial seizure load (ISL), weld load (WL), wear‑load curve, Load‑Wear Index (LWI) and mean wear scar diameter (MWSD) for short (10 s or 60 s) and long (60 min) durations.
- Apparatus and consumables: Four‑ball machine specifications, ball material and dimensions (refer to Annex A), cleaning solvents and sample preparation.
- Calculations and precision: Algorithms for LWI and wear results, precision statements (repeatability/reproducibility) and required test reporting.
- Normative annexes: Ball specifications and mean Hertz load data sheet to support consistent execution.
Applications
- Quality control and acceptance testing in lubricant manufacturing
- Product development and R&D for oils, hydraulic fluids and lubricating greases
- Performance comparison for OEMs, tribology labs and independent test houses
- Supplier qualification, specification compliance and failure analysis where EP and anti‑wear performance matter
- Regulatory and procurement specifications that reference standardized lubricant test methods
Related Standards
EN ISO 20623:2018 aligns with and helps bridge comparisons to other four‑ball methods such as:
- ASTM D2266, D4172, D2596, D2783
- Energy Institute IP 239
- DIN 51350 series
Referencing these standards is useful when comparing historical data or meeting multiple regional requirements.
Keywords: EN ISO 20623:2018, ISO 20623, four‑ball method, extreme‑pressure testing, anti‑wear testing, Load‑Wear Index, weld load, initial seizure load, MWSD, lubricant testing.