METHOD FOR PREVENTING CRACK FLAW DURING HOT ROLLING OF FERRITIC STAINLESS STEEL

摘要

PURPOSE:To eliminate the generation of crack flaws on the surface of a steel sheet in the stage of hot rolling a ferritic stainless steel by specifying the depth of the coarse ferrite particles in the slab surface part formed during heating of a slab to a specific value or below. CONSTITUTION:The depth of the coarse ferrite particles in the slab surface layer part formed during heating of the slab of the ferritic stainless steel is kept at =500mum in the stage of heating the slab to the prescribed temp. The control of said depth is executed by a method such as coating of a decarburization preventing agent on the slab surface, covering of the slab surface with a thin steel sheet, increasing of the nitrogen content in the steel to =0.02% or control of the slab heating conditions so as to satisfy the relation; heating temp. ( deg.C) + heating time (min) =1,240. The generation of the crack flaws on the surface of the hot-rolled steel sheet is thus prevented.