Variation of Hot Ductility Behavior in As-Cast and Remelted Steel Slab

Abstract

Variations in the hot ductility behavior of as-cast and remelted steel slabs were investigated. The specimens were prepared directly from the surface of an as-cast continuous casting slab. The slab was then remelted to assess the effect of the same on the cast structure. A high temperature tensile test was used to obtain hot ductility data. In the case of 0.18 wt.% carbon steel, hot ductility improved with increasing strain rate for both as-cast and remelted slab specimens. Comparing the results obtained from the as-cast and remelted specimens, similar hot ductility values were observed in the low temperature range. At higher temperatures, however, the remelted slab specimen had a higher R/A (reduction of area) value. The decreased R/A value of the as-cast specimens in the high temperature region could be explained by the increase in the initial grain size due to the slow cooling of the large slab during continuous casting. This means a lower hot ductility value than that obtained from remelted specimen should be assumed in the case of the application of lab data to an actual continuous casting process.