METAL WORKING OIL COMPOSITION

摘要

PROBLEM TO BE SOLVED: To obtain a metal working oil composition which foams up less when used by mixing a lubricating base oil with an overbased alkali metal sulfonate and a specified aliphatic hydrocarbon. SOLUTION: A lubricating base oil having a kinematic viscosity (at 40 deg.C) of 1-100mm<2> /s and a pour point of -40 deg.C or below is mixed with 1-30wt.%, based on the total composition, overbased alkali metal sulfonate having a total base value of 100mgKOH/g or above and 0.1-50wt.% 12-30 C aliphatic hydrocarbon having a kinematic viscosity (at 40 deg.C) of 1-20mm<2> /s and optionally various known additives to obtain a metal working oil composition having a total base value of 1-50mgKOH/g.