Abstract:By means of high temperature thermal oxidation accelerated simulator,the changes of the appearance,viscosity〖JP〗 and acid value of the hydrocarbon lubricating oil at different temperatures with or without addition of metallic Fe were studied,and the composition and structure of the reaction oil samples was analyzed by GC/MS.The results show that,after the hightemperature oxidation reaction,the oil sample with metallic Fe has a darker color,a lower viscosity and higher acid value compared to the sample without Fe,indicating that the deterioration of the oil sample is greatly accelerated after adding the metallic Fe.GC/MS analysis results show that a large number of small molecules of alkane and olefin compounds are produced,and a small amount of compounds such as alcohols,ketones,acids,esters and so on,are also formed,which cause the decay of color,viscosity,and acidity of oils.