Segregation in twin roll strip cast steels and the effect on mechanical properties

Abstract

Strips of low carbon steels containing high contents of P and Cu have been produced by twin roll strip casting. The as-cast strips containing more than 0.1 mass% P exhibited obvious inverse surface segregation, which was difficult to be eliminated by the subsequent annealing treatments. After cold rolling and annealing treatment at 625°C for 30min, the strip containing 0.1 mass% P exhibited similar plastic deformation and rupture behaviors with the strip containing 0.01 % P, showing no obvious deteriorating effects of P on the ductility of as-cast strip. With increasing P content in steel, more cleavage cracks, micro voids and inter-granular rapture were observed in the fractured areas after tensile testing, which are believed to have been induced by the segregation of P in as cast strips. These results provide primary guidance for recycling dirty steel scraps, © 2007 ISIJ.