Papers by Keyword: Peritectic

Abstract: The problem of transverse crack formation in continuously cast steel has been an issue for over 30 years. The crack susceptibility depends not only to the steel composition, but also to the temperature history during casting. To improve the surface quality, two key solutions have been suggested; adjusting the straightening stage to an appropriate temperature range, out of hot ductility trough, and/or alloy modification. These solutions have certain limitations and difficulties still exist for grades such as peritectic steels containing Nb or V. In this article, the hot ductility of a peritectic steel grade with Nb has been studied under direct cast conditions. This was performed using a Gleeble 3800 thermo-mechanical simulator under two critical strain rates. In addition, the transverse crack formation and appearance, as well as the application of infrared camera to study the surface temperature profile of the slabs is presented.

Abstract: Simplified models of micro-segregation are in common use in academia and industry. An issue regarding the accuracy of these approaches is addressed, before describing extensions required for the sponsor (Corus/Tata). It is shown that the adopted growth rate law of the solid is of equal importance as the diffusivity and the partition coefficient. By making the growth rate part of the solution rather than arbitrarily imposed (e.g. parabolic growth), dramatic errors are avoided. This approach has now been extended to the peritectic transformation in steel. Also included are dendrite arm coarsening and predictions of the solute profiles across the solid and their sub-solidus homogenization. The results of this streamlined model compare very well with experimental data and Finite Difference model calculations despite operating orders of magnitude more quickly.