Vegetable oils as metal quenchants: A comprehensive review

There is an ongoing interest in the development and use of renewable base stocks to formulate quenchants. The most common criterion of vegetable oils as renewable base stocks is their biodegradability and that they be non-toxic. A comprehensive overview of all aspects of vegetable oils that impacts their potential for commercial use is provided. Topics discussed include: vegetable oil structure, processing, physical properties, classification, biodegradation and toxicity; oxidation and inhibition; wetting and wetting kinematics; and applications. As a class, vegetable oil-based quenchant formulations reported in the literature to date exhibit a number of disadvantages, the most notable being their relatively poor thermal-oxidative stability in comparison with petroleum oil-based quenchants in use. Potential pathways to vegetable oilbased fluid compositions that may rival the thermal-oxidative stability of many petroleum oil-based quenchants were introduced. Copyright © 2017 by ASTM International.