quenched with water and pickled the cooling for the quenching from 600 to 300 u00b0 c was well in excess of 1 u00b0 c sec the as rolled sheet was cold rolled to a thickness of 0 25 mm annealed at 300 u00b0 c for 30 min water quenched and pickled process h comparison a case where there was not intermediate heat treatment following the hot working and quench step a sample measuring 40 u00d7 40 u00d7 30 mm was cut out of the ingot at a site one third of its thickness as measured from the bottom the sample was heated to 850 u00b0 c and hot rolled from the thickness of 30 mm to 10 mm and thereafter quenched with water and pickled the cooling rate for quenching from 600 to 400 u00b0 c was well in excess of it sec the as rolled sheet was cold rolled to a thickness of 0 25 mm annealed at 500 u00b0 c for 90 min water quenched and pickled process i comparison a case where the temperature for the intermediate heat treatment was higher than 520 u00b0 c a sample measuring 40 u00d7 40 u00d7 30 mm was cut out of the ingot at a site one third of its thickness as measured from the bottom the sample was heated to 850 u00b0 c and hot rolled from the thickness of 30 mm to 10 mm by a reduction ratio of 67 and thereafter quenched with water and.