Author :
NaJafi- Zadeh, A.,Jonas, J.
Abstract :
The influence of total Finishing strain (from 2.1 to 3.2) and first finishing temperature (from 990 to 930)was investigated by means of multi-pass torsion tests on three interstitial free (IF) steels containing Ti and/or Nb.All the tests were carried out at a strain rate of 2. Under strip rooling conditions. Static recrytallization is responsible for the high degree of interpass softening in the early passed of rolling.During the final passes, dynamic recrystallixation occursto a degree that depends on the composition of the steel, the total finishing strain and the temperature.The critical temperatures of the steels were defined by using a simulated plate rolling schedule. Subjected to the same strip rooling schedule, the niobium stabilized steel had the finest, whereas the titanium stabilized gard had the largest ferrite grain size.The present IF steels exhibit higher no-recrystallization temperatures during strip rooling 1-2 sec interpass times ) than under plate rolling conditions (30 sec interpass times).KEY WORDS: interstitial free (IF) steel; hot strip rooling; dynamic recrystallization; no- recrystalization temperature; hot torsion test.
