T. Hiruta, Y. Matsubara, N. Nakata, M. Miyake, T. Kuroki and Y. Sodani
Two innovative processes have been developed in order to produce
ultra fine grained steel at the hot strip mill. One is based on high
speed, large reduction forging, the other on combined rolling/bending
strain accumulation. Both processes afford drastic reductions
of the strip ferrite grain-size.