Patent ID: 8734601

Claim:
Method of hot rolling a slab or strip or sheet of metal, wherein 1.a) the slab or strip or sheet after casting is subjected to one or more deformations in a hot rolling mill comprising a series of roll stands for completely eliminating a cast structure and for producing a uniform, fine, recrystallized austenite structure with a grain size of 40 μm+/−20 μm, and in micro-alloyed steel with a grain size of 30 μm±10 μm, wherein >90% of micro-alloying elements in the steel at the end of this step have been dissolved, and 2) the slab or the strip or the sheet is then subjected to cooling in a second step for producing a fine-grain microstructure in which no individual coarse grains are present, whose grain limits are characterized by small angle grain limits, wherein between at least two roll stands of the hot rolling mill, the slab or strip or sheet is subjected to heating while step 1.a) is carried out, and wherein, in at least the first roll stand in the rolling direction the upper and lower work rolls are driven through separate drives, wherein directly after exiting from a roughening stand, the slab or the strip or the sheet is pulled by a pair of drive rollers into an induction heating unit and subsequently, and the slab or strip or sheet is in a step 1.b between the steps 1.a) and 2) subjected to one or more deformations of the recrystallized austenitic structure for producing a flatly stretched austenite structure, and wherein heating is carried out into a recrystallized temperature area, up to complete recrystallization.