255

285A

285A

(1992)

P.1-18

The hot deformation behaviour of intertitial free (IF) steels containing Ti and/or Nb under strip or plate rolling were investigated by means of multi pass torsion tests.All the tests were carried out at a strain rate of .There types of strip rolling schedules (they differed only with respect to the number and total strain of finishing passes)and one type of plate rolling were employed. Under strip rolling conditions the effects of total finishing pass strain and first finishing pass temperature was investigated. The plate rolling schedule used in order to determined the three critical hot deformation temperatures i.e., T A and A . The results indicate that, under strip rolling conditions, static recrystallization is responsible for the high degree of interpass softening in the early passes of rolling. Duting the final passes dynamic recrystallization occurs to a degree that depends on the composition of the steel, the total finishing strain and the temperature. These steels exhibited higher no-recrystallization temperatures (T ) during strip rolling than under plate rolling conditions.

77/11

Shahsavary

GN132417