Study on the creep behavior and microstructure evolution of a low alloy steel in continuous casting processing

Abstract

In continuous casting processing, the solidifying slabs undergo creep deformations under complex thermomechanical stresses, which may cause microstructure anisotropy and flaws within the casting slabs. Therefore, it is vital to acquire insights into the creep properties and microstructure characteristics of slabs tailored by thermomechanical conditions. To clarify above issues, an as-cast low alloy steel was crept under continuous casting processing conditions to explore the involved creep phenomena. The creep performances correlated with temperatures and stresses were evaluated, the results pronounced the dominant role of temperature scheme governing the creep procedure compared to stress. A constitutive model was established based on an empirical physics-based constitutive model to predict the creep curves. The crept microstructures were characterized to reveal the dependence of substructure characteristics on creep temperatures. The reduced LABs (low angle boundaries) and dislocations under higher temperatures indicated the deteriorated creep resistance and enhanced susceptibility to microcrack initiation and propagation, which accounted for the occurrence of internal microcracks within the continuous casting slab. The results can provide fundamental data for utilizing the creep deformation to develop straightening technology in continuous casting processing.