Metalworking fluids from vegetable oils

The biodegradability of metalworking fluids has assumed very high priority. Biodegradable metalworking fluid formulations consist of vegetable oil, an emulsifier, co-surfactant, fungicide and additives. Non-edible vegetable oils such as neem, ricebran, and karanja oil are renewable, biodegradable and cheaper than synthetic fluids. Oleates and fatty-acid amides of these oils have been used as emulsifiers to eliminate biohard emulsifiers. Additives are used to achieve a high level of performance. Metalworking soluble oil formulations were evaluated for physicochemical characteristics such as emulsion and thermal stability, copper-strip corrosion, iron chip corrosion, deposit-forming tendency on hot metal surfaces, and lubricity. Oil–water micro-emulsions of these oils have higher stability. The emulsions were stable over a wide range of temperatures. Performance of formulations from all three oils are found at par with the ASTM specifications. Neem oil based formulation showed better characteristics than ricebran and karanja oil. Copyright © 2006 John Wiley & Sons, Ltd. key words: metalworking fluids; neem oil; karanja oil; ricebran oil; soluble oil; biodegradable lubricant