High temperature oxidation behavior of 310S heat-resistant steel

The oxidation kinetics and film structure of two kinds of 310S heat-resistant steels (1# and 2#) with different grain sizes and composition at 800-1100 ℃ were studied by static oxidation discontinuous mass gain method. The differences of oxidation properties between the two steels were compared, and the growth mechanism of oxide film and the reasons for the differences were clarified. The results show that the oxide film is composed of Si-rich oxide layer and Cr-rich oxide layer and the oxidation rate of sample 1# is lower at 800-900 ℃; Cr-Mn oxide layer is added to the oxide film at 1000 ℃ and is transformed into Cr-Mn-Fe oxide layer at 1100 ℃, and their oxidation rates are similar; on the whole, the oxide film of sample 2# is denser, smoother, more adherent and more protective at all temperatures. Particularly, the spinel layer and the chromium oxide layer of the two are greatly different in the form at 1100 ℃, and the form of the oxide film of sample 2# is more conducive to long-term oxidation resistance. In general, the oxidation resistance of sample 2# is better than that of sample 1#. The smaller average grain size and more uniform grain of sample 2# improve the diffusion flux of preferred oxidation elements and reduce the uneven growth of oxide film, resulting in the differences of oxidation properties between the two