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M. Lückl, S. Ilie, J. Six, E. Kozeschnik:
"Surface Microstructure Control during Continuous Casting of Micro-Alloyed Steel";
Talk: Materials Science & Technology 2013, Montreal; 2013-10-27 - 2013-10-31; in: "Materials Science & Technology 2013 (CDROM)", (2013), ISBN: 978-0-87339-762-9; 433 - 438.

During continuous casting of steel, the slab is exposed to severe thermal and mechanical stresses. These may trigger formation and growth of cracks. Particularly, at temperatures in the region of the second ductility trough, deformation can become critical. A low ductility level is often observed in a temperature range of 600°C to 1200°C, where the bending of the slab is commonly performed. Slab surface transverse cracking occurs because of strain concentrations at film-like ferrite along the austenite grain boundaries or as a consequence of precipitation of second-phase particles. In the present investigation, the mechanism of surface microstructure control is investigated to prevent transverse cracks. Tensile samples are taken from regions close to the upper surface of the slab. The microstructure changes are controlled by a double phase transformation as a result of intensive cooling and reheating, leading to significantly improved mechanical properties and a crack-free slab surface.

hot ductility, surface structure control cooling, double phase transformation, grain refinement