High-temperature Oxidation Behaviors of GL-A32 and B610E Heavy Plates at Reheating Temperatures

In order to understand the high-temperature oxidation behaviors of heavy plate steels in the reheating process, the oxidation kinetics of two typical hot-rolled heavy plate products GL-A32 and B610E in the air at temperatures of 1100 ~ 1200 ℃ was measured by the thermo-gravimetric analysis method (TGA). The morphology and composition of the oxide scales were characterized by scanning electron microscopy (SEM) and X-ray diffration (XRD). The results showed that the oxidation weight-gain of the steels increased dramatically with increasing the temperature. The oxidation process could be divided into two stages, i. e., the initial rapid transient oxidation stage and the steady oxidation stage. The outer part of oxide scales was mainly composed of Fe2O3, Fe3O4 and FeO, but the composition of each phase changed significantly with oxidation temperature. The oxide scales formed at 1100 ℃ and 1150 ℃ were grey-black, with blistering in large areas, thin and easy to remove. The oxide scale formed at 1200 ℃, however, was light-grey and had high hardness.