Micropitting performance of mineral and biodegradable ester gear oils

摘要

Purpose - This paper's aim is to present the gear micropitting performance of two industrial gear oils: a standard mineral lubricant (CM) containing a special micropitting additive package and a biodegradable ester with low toxicity additivation. Design/methodology/approach - Gear micropitting tests were performed on the FZG machine, using type C gears made of case carburized steel. Lubricant samples were collected during the tests for analyzing the wear particles generated during operation. Post-test analysis included the visual inspection of the teeth flanks and the assessment of the micropitting area, the mass loss of the gear, the ferrometric analysis of the lubricant samples and the surface roughness measurement of the teeth flanks, below and above the pitch line. Findings - The micropitting performance of the two lubricants was very similar, confirming the advantage of using the ester lubricant (CE) as an industrial gear oil, now that it is an environmentally friendly product. Research limitations/implications - The tests were only performed on carburizing steel and refer to the tested lubricants. Practical implications - The study confirms the appropriateness of biodegradable ester oil to industrial gear applications, allowing the replacement of environmentally harmful gear lubricants. It shows that the micropitting protection conferred is similar to that exhibited by highly additivated CMs. Originality/value - The paper shows the applicability of biodegradable CEs to gear lubrication, mainly where it concerns micropitting protection, and shows its potential advantages, together with the biodegradability.