Corrosion resistance, are superior in compactibility and material uniformity the ferrite stainless steel hot rolling steel sheet and its production manner

摘要

PROBLEM TO BE SOLVED: To stably improve corrosion resistance, formability, and uniformity of material by adding Ti or Nb to a ferritic stainless steel and also regulating the grain size of carbides according to the position in plate thickness at the time of hot rolling into plate. ;SOLUTION: As a stabilizer for impurities C and N, either or both of Ti and Nb are further added to a ferritic stainless steel having a composition containing, by weight, 0.02% C, 2.0% Si, 0.8% Mn, 0.05% P, 0.03% S, 10-25% Cr, 1.0% Ni, 0.02% N, and 0.1% Al so that inequalities (Ti/48+ Nb/93)/(C/12+N/14)1.5 and (Ti+Nb)0.5% are satisfied. At the time of hot- rolling a slab of this steel into plate, a roughed sheet bar is temporarily coiled at 800-1050°C surface temp. and then finish rolling is carried out from the coiling end to regulate the average grain size of carbides in the stainless steel plate so that it is ≥0.02μm in the surface layer part and ≥0.05μm in the central part of the steel plate, respectively.;COPYRIGHT: (C)1998,JPO