Effect of Soybean Oil and Palm Oil Oxidation Stability On the Variation of Heat Transfer Coefficients and Residual Stress

The potential use of vegetable oil derived industrial oils continues to be of great interest because vegetable oils are relatively non-toxic, biodegradable and they are a renewable basestock alternative to petroleum oil. However, the fatty ester components containing conjugated double bonds of the triglyceride structure of vegetable oils typically produces considerably poorer thermal-oxidative stability than that achievable with petroleum basestocks under typical use conditions where furnace loads of hot steel (850 °C) are rapidly immersed and cooled to approximately 50-60 °C bath temperatures. This is especially true when a vegetable oil is held in an open tank with agitation and exposure to air at elevated temperatures for extended periods of time (months or years). Unfortunately, as vegetable oils degrade, their fluid viscosity is expected to increase resulting in decreased quench severity. Clearly, thermal-oxidative stability is essential. This paper will review thermal-oxidative stability and quenching performance variation with respect to time of soybean oil and palm oil using an accelerated ageing test and the resulting impact on the heat transfer coefficient and residual stress obtained by simulated time-temperature cooling performance obtained using the ASTM D6200 standard (12.5 mm dia x 60 mm) cylindrical INCONEL 600 probe. Particular focus will be on the numerical simulation of the resulting heat transfer coefficients using HTMod and residual stress using Abaqus.