Metal working fluid

An oil for metal working comprising a triester of fatty acids and glycerin,

• the content of oleic acid in the fatty acids being 40-98% by mass based on the total amount of the fatty acids.

The oil for metal working according to claim 1, wherein the oil further comprises a hydrocarbon oil and the content of said triester is 1-50% by mass based on the total amount of the composition.

The oil for metal working according to claim 1, wherein the content of linoleic acid in the fatty acids is 1-60% by mass based on the total amount of the fatty acids.

The oil for metal working according to claim 1, wherein the content of C1-C16 fatty acids in the fatty acids is 0.1-30% by mass based on the total amount of the fatty acids.

The oil for metal working according to claim 1, wherein the content of C6-C16 fatty acids in the fatty acids in 0.1-30% by mass based on the total amount of the fatty acids.

The oil for metal working according to claim 1, further comprising a monoester and/or a diester.

The oil for metal working according to claim 1, being used as a cutting oil, a grinding oil or a roll forming oil.

The oil for metal working according to claim 1, being used as a metal working oil for heavy machining, a metal working oil for difficult machining or a metal working oil for machining of difficult-to-cut materials and/or difficult-to-grind materials.

The oil for metal working according to claim 1, being used as an oil for metal working with a minimal quantity lubricant system.