Patent ID: 7094295
Filing Date: 2006-08-22
Classification: C21D,C22C

Abstract:
1. A method of manufacturing a ferritic stainless steel sheet having good workability with less anisotropy, which comprises the steps of: providing a ferritic stainless steel consisting essentially of 0.03 mass % or less of C, 0.03 mass % or less of N, 2.0 mass % or less of Si, 2.0 mass % or less of Mn, 0.07–0.6 mass % of Ni, 9–35 mass % of Cr, 0.15–0.80 mass % of Nb and the balance being Fe except inevitable impurities; precipitation-heating said stainless steel at a temperature (T) in a range of 450–750° C. for a time period (t) not longer than 20 hours with the provision that a value λ defined by a formula of λ=(T+273)·(20+log t)/1000, whereby temperature is in degree centigrade and time is measured by hours, is controlled within a range of 13–19 so as to distribute Nb-containing precipitates of 0.5 μm or less in particle size at a ratio of 0.4 mass % or more; and finish-annealing said stainless steel at a temperature in a range of 900–1100° C. for a time period not longer than 1 minute.