The loss of hot ductility (HD) of steel during continuous casting is usually attributed to the intergranular precipitation of V and Nb (C, N) as well as segregation of atoms to grain boundaries. This loss of hot ductility in the temperature range 700--1100 °C in carbon and low alloy steels is related to transverse surface cracks during the straightening operation of the continuous casting process of steel. An additional problem, found in peritectic steels, is its very coarse as cast structure, which is very prone to cracking during the straightening stage. In this regard, two major solutions have been suggested to date to improve hot ductility, adjusting the straightening stage to be below or above the low hot ductility region and chemical composition modification. However, both the solutions have limitations and the problem of cracking during continuous casting is still persistent. In this study, a peritectic steel was melted in-situ and the hot ductility trough was quantified at temperatures ranging from 700 to 1100 °C. It was also subjected to very high temperature deformation in the single phase austenite region (1400--1300 °C) during cooling from the solidus temperature. It was noticed that such deformation can improve the hot ductility, which could alleviate cracking problem during continuous casting. Microstructural studies showed that such improvement can be attributed to grain refinement owing to dynamic recrystallization during the deformation applied after solidification. Fracture analysis revealed that the deformation altered the grain boundary segregation as well. The Auger Electron Spectroscopy (AES) measurements showed that the very high temperature deformation lowered the concentration of detrimental elements, such as S, N, Mn and C, at grain boundaries. This also contributed to the HD improvements.;The steel specimens were also reheated to temperatures below the solidus and subjected to the very high temperature deformation prior to HD testing. As was expected, the reheated specimens showed better HD than the melted ones. Microstructural examination showed that the very high temperature deformation encouraged recrystallization and grain refinement. AES studies of the reheated specimens showed no change in concentration of detrimental elements.
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