TY - GEN

T1 - High-temperature oxidation of steel recycled from scrap: The role of tramp elements and their influence on oxidation behavior

AU - Gaiser, Georg

AU - Presoly, Peter

AU - Bernhard, Christian

PY - 2023/6/12

Y1 - 2023/6/12

N2 - Reducing CO2 emissions in steel production is one of the major challenges for the European steel industry in the upcoming years, whereby the remelting of scrap in electric arc furnaces is the most important bridging technology. Depending on the scrap type, steel scrap contains different levels of undesirable by-elements, also referred to as tramp elements. Technical and economic limitations lead to non-negligible tramp element contents in the steel. Those can affect high-temperature oxidation mechanisms in casting, rolling and annealing processes, leading to various types of internal oxidation phenomena and the formation of (liquid) phases at the interface. Within the scope of the present publication, oxidation experiments for different steels containing tramp elements were performed by means of thermogravimetric analyses. The influence of several time-temperature cycles and atmospheres were analyzed. Particularly noteworthy are the experiments with an oxidation atmosphere simultaneously consisting of synthetic air and water vapor. Oxidation intensifies in the presence of water vapor, leading to a higher accumulation and formation of metallic copper phases at the interface. Steels with a higher trace level of nickel show significantly higher tendencies to form intergranular oxidation due to fayalite formation. The results provide meaningful data to improve the understanding of high-temperature oxidation mechanisms in steel processing with a particular focus on continuous casting and serve as a basis for further experiments.

AB - Reducing CO2 emissions in steel production is one of the major challenges for the European steel industry in the upcoming years, whereby the remelting of scrap in electric arc furnaces is the most important bridging technology. Depending on the scrap type, steel scrap contains different levels of undesirable by-elements, also referred to as tramp elements. Technical and economic limitations lead to non-negligible tramp element contents in the steel. Those can affect high-temperature oxidation mechanisms in casting, rolling and annealing processes, leading to various types of internal oxidation phenomena and the formation of (liquid) phases at the interface. Within the scope of the present publication, oxidation experiments for different steels containing tramp elements were performed by means of thermogravimetric analyses. The influence of several time-temperature cycles and atmospheres were analyzed. Particularly noteworthy are the experiments with an oxidation atmosphere simultaneously consisting of synthetic air and water vapor. Oxidation intensifies in the presence of water vapor, leading to a higher accumulation and formation of metallic copper phases at the interface. Steels with a higher trace level of nickel show significantly higher tendencies to form intergranular oxidation due to fayalite formation. The results provide meaningful data to improve the understanding of high-temperature oxidation mechanisms in steel processing with a particular focus on continuous casting and serve as a basis for further experiments.

M3 - Conference contribution

BT - Proc. 6th ESTAD

T2 - 6th ESTAD (European Steel Technology and Application Days) 2023

Y2 - 12 June 2023 through 16 June 2023

ER -