Evaluation of vegetable oils as pre-lube oils for stamping

Vegetable oils can offer a valuable alternative to mineral or synthetic oils as a source for manufacturing lubricant oils for stamping of sheet metal parts. They are biodegradable and have better intrinsic boundary lubricant (BL) properties, due to the presence of long chain fatty acids in their composition. This work evaluates the performance of some of these vegetable oils under the typical BL conditions found during stamping of car body parts. The values found for the friction coefficient under BL conditions are low and remain stable, with values between 0.11 and 0.13 for steel sheet, 0.09–0.12 for galvannealed sheets and 0.10–0.13 for zinc coated sheet, giving a similar or even better performance than mineral based compounded oils.