Abstract
The recrystallization behavior of ferritic stainless steel in high speed hot rolling has been investigated in relation to the strain distribution through the thickness of the rolled strip. The strip of which the size was 2×20×430 mm was rolled at the temperatures from 900°C to 1050°C and at the rolling speed of 20 m/s with or without lubrication. The rolled specimen was quenched in water at the interval of 25 ms after rolling. The redundant shear strain caused by friction forms severely sheared region beneath the surface with the thickness of about 100μm. The maximum equivalent strain εmax in severely sheared region reaches about 4 times of compressive strain and εmax in rolling without lubrication, is always larger than that in lubricated rolling.
Extremely fine recrystallized grains are formed in severely sheared region when εmax exceed a critical value, which is dependent on ZENER-HOLLOMON parameter Zmax in severely sheared region and independent of lubrication condition. The size of the recrystallized grain is also strongly dependent on Zmax.
From these results and optical micrographs, it is concluded that the recrystallized grains observed in this study are statically recrystallized ones.
