Influence of lubricant type in gear scuffing

Purpose - This paper aims to investigate the scuffing load-carrying capacity of three gear oils: a standard mineral lubricant containing extreme pressure and anti-wear additives (M0) and two biodegradable saturated esters containing low toxicity additives (E1 and E2). Design/methodology/approach - Four-ball wear tests were performed, according to standard ASTM D4172. Results from the wear scar diameter and from ferrographic analysis of the test oil samples are presented and related to the lubricant properties. The physical, chemical and biodegradability properties of the lubricants are presented and compared. FZG gear scuffing tests were performed, according to standard DIN 51535, in order to evaluate the scuffing load-carrying capacity of the two oils. Two reference tests were performed, A20/16.6/90 and A10/16.6/90. Findings - Test results include scuffing load stage, maximum oil bath temperature, pinion weight loss and surface roughness measurement of the teeth flanks. Originality/value - The paper provides information on the scuffing load-carrying capacity of three gear oils.