Abstract
According to previous reports, Al-Mn alloy could be produced as the fine grain sheet by means of preheating of slab, flash annealing of sheet. The work has been carried out, in order to be of use producing fine grain 3S sheet in the industrial scale, the conditions of slab preheating, heat treatment of sheet, and cold roll reductions etc.
Results obtained are:
(1) Preheating of slab is effective to refine the recrystallization grain size of sheet. As the slab be 50kg weight and 120m/m thick, preheating may be sufficient 550°C 12hours.
(2) When annealed with the heating velocity of 15°C/min and up as preheated slab, the grain size of sheet has been 0.15m/m and less.
(3) Instead of preheating of slab, intermediate soaking of sheet is also effective to the fine grain, and it is desirable to heat higher temperature.
(4) Germination of grain brings about on the reduction range of cold rolling being between 50% to 70%. The reduction range of grain growth tends to change to lower reduction per cent as the sheet produced with preheated slab.
