Average carbon content change during gas-solid decarburization of 2 mm iron sheet with a high carbon content

Abstract

The average carbon content after decarburization is an important criterion in judging the feasibility of the solid-state steelmaking process. To investigate the change mechanism of the average carbon content, the gas-solid decarburization of 2 mm iron sheet in weak oxidizing atmosphere (Ar + H2 + H2O) at 1293, 1353, and 1413 K is studied. The influences of decarburization time and temperature are considered. Increasing both the temperature and time can enhance decarburization. The gas-solid decarburization reaction of 2 mm iron sheets is nearly a first-order reaction, and the activation energy of the decarburization reaction is 144.9 kJ/mol. It was found that the diffusion of carbon from the interior of the sheet to the reaction interface is the rate-controlling step. The relationship between decarburization time, temperature, and average carbon content is precisely described by an empirical formula. A new segmented heating method is developed. With this new method, 0.28 mass% C sheets can be produced from 4.15 mass% C sheets with thickness of 2 mm in 70 min.