Abstract: The present invention provides a lubricating oil composition comprising at least one type of base oil selected from mineral oils and synthetic oils, and a succinate ester and a sarcosinic acid as rust prevention agents. The succinate ester content is preferably set at 0.01 to 0.1 wt. %, and the sarcosinic acid content is preferably set at 0.001 to 0.01 wt. %. Further, they are preferably set such that the resulting weight ratio of the succinate ester content and sarcosinic acid content is 1:0.01 to 0.7. The lubricating oil composition according to the present invention shows excellent rust prevention properties and a satisfactorily long oxidation lifetime. Further it allows to attain a high level of anti-sludge performance and extreme pressure performance and lubrication performance, even when it is used for example in turbine bearings in combined cycle generators having multiplier gears operated under severe high temperature and high pressure conditions.

Abstract: The present invention provides a lubricating oil composition comprising at least one type of base oil selected from mineral oils and synthetic oils, and a succinate ester and a sarcosinic acid as rust prevention agents. The succinate ester content is preferably set at 0.01 to 0.1 wt. %, and the sarcosinic acid content is preferably set at 0.001 to 0.01 wt. %. Further, they are preferably set such that the resulting weight ratio of the succinate ester content and sarcosinic acid content is 1:0.01 to 0.7. The lubricating oil composition according to the present invention shows excellent rust prevention properties and a satisfactorily long oxidation lifetime. Further it allows to attain a high level of anti-sludge performance and extreme pressure performance and lubrication performance, even when it is used for example in turbine bearings in combined cycle generators having multiplier gears operated under severe high temperature and high pressure conditions.