Effect of oxidation behavior on heat transfer dynamics performance of hot stamping steel

Based on static weight loss method and metallographic method, this paper investigated the effect of soaking time on the oxidation behavior of typical cold rolled hot stamping steel 22MnB5. With the results of the thickness of oxidation and decarburization scales, the regression equations of weight loss and reduction of oxide scales were built. The characteristic parameter named equivalent interfacial-heat-transfer-coefficient (IHTC) was got by inverse numerical calculation with ABAQUS, which was taken to describe the effects of thickness of oxidation and decarburization scales and loads based on related heat transfer dynamics performance in process of hot stamping. The results indicate that the weight loss per unit area and thickness reduction of B1500HS steel with 1. 6mm thickness can reach 0.471 mg/mm² and 99.3 μm respectively, the depth of decarburization can reach 87.0 μm at 900 °C. The oxidation of the mentioned steels obeys the parabolic law, which presents high oxidation rate at initial stage of soaking, then slows down obviously after 4~5 min. The multiple correlation coefficients between regression analysis and weight loss and reduction of oxide scales are over 0.95. The equivalent IHTC has negative relationship with the thickness of oxidation scale and it also increases with the interface load. The results show that oxidation behavior has a significant influence on heat transfer dynamics performance in hot stamping process.