The Impact of Hot Rolling Temperature after Reheating in the New Generation Strip Casting Process on Structure‐Property Relationship in Extra‐Low Carbon Steel

Abstract

AbstractThere is currently a significant interest in extending the application of novel strip casting technology to a wide range of high strength steels because it allows strip to be cast directly from the liquid metal with minimal rolling. In view of the current interest in developing strip casting technology, we explore here the structure‐property relation in extra‐low carbon steel, with particular emphasis on an important parameter, the rolling temperature after reheating. The as‐cast strip exhibited continuous yielding behavior, significantly lower yield ratio and higher elongation than hot rolled sheets. Coarse and recovered microstructure with Lüders‐like deformation bands was formed when the reheating temperature was in the range of 800–900 °C and followed by one‐pass hot rolling, while coarse‐fine mixed microstructure and fine and homogeneous microstructure was formed at 950 and 1000 °C, respectively. These differences in microstructure led to a transition from continuous yielding to discontinuous yielding with increase in reheating temperature from 800 to 1000 °C and followed by hot rolling. The present study underscores that a good combination of yield strength and elongation that is comparable to conventional hot rolled sheets can be successfully obtained through optimization of hot rolling temperature after reheating in the strip casting process.