2024 Volume 69 Issue 2 Pages 134-144
Rolling contact fatigue, RCF, of steel under lubrication with alkyl diphenyl ether, ADE, and poly alpha olefin, PAO, in three environmental gas conditions was studied. RCF tests were conducted at 150°C with ball and disk configuration, and hydrogen concentration in steel, chemical changes of oils and rolling surfaces were analyzed after the tests. In order to confirm basic oil properties, such as viscosity-pressure coefficient of oil under contact condition, film thicknesses under pure rolling contact were also measured by interferometry method with using ball on disk type tribo tester. ADE had greater RCF life in nitrogen than PAO with the same viscosity. This was caused by ADE’s higher viscosity-pressure coefficient, carbon-rich surface film formation and higher chemical stability to decompose and to generate hydrogen on nascent steel surface. On the other hand, in air, ADE also showed greater RCF life than PAO. This was ascribed to higher anti-oxidation stability of ADE.
