Abstract: A method for automatically controlling the width of a slab during hot rough-rolling thereof, which comprises: arranging a pair of horizontal broadening rolls each having at least one annular projection in a hot roughing mill train comprising a plurality of roll stands; calculating an amount of roll gap correction of said pair of broadening rolls on the basis of the variation in the width of said slab during hot rough-rolling on said hot roughing mill at the entry of said pair of broadening rolls; and, controlling the roll gap of said pair of broadening rolls in response to said amount of roll gap correction; thereby automatically controlling the width of said slab during hot rough-rolling thereof to a prescribed value at a high accuracy in accordance with the finishing width of a steel strip, and at the same time, automatically correcting variations in the width of said slab during hot rough-rolling thereof at a high accuracy.

Abstract: In the withdrawing stage following the secondary cooling zone, each pair of rolls of a plurality of pairs of rolls reduces the cross section less than 1.5 percent at the portion between the liquidus line and solidus one in unsolidified phase, thereby to produce a sound cast piece without producing the known center segregation and the known center porosity.

Abstract: A method of shape control for a tandem mill for rolling strip, wherein the shape of the rolled strip at the delivery side of the final stand is detected to provide a signal corresponding to the long-edge shape, whereby the pattern of roll bending force for two or more latter stands are adjusted according to the signal or signals obtained in order to effect desired shape control without causing variations in the thickness of the strip at the delivery side of the last stand.