| 摘要 |
PROBLEM TO BE SOLVED: To provide a cold rolled ferritic stainless steel sheet having high elongation and excellent press formability, and to provide its production method. SOLUTION: A steel stock having a composition comprising, by mass, 0.010 to 0.045% C, 0.01 to 0.05% N,≤1% Mn, 13 to 20% Cr and≤0.01% Al, and also comprising C and N in such a manner that the volume ratio (v) of Cr carbonitride defined by v(%)=100×ä0.0196C+0.0015N}(wherein, (v): the volume ratio (vol.%) of Cr carbonitride, and C and N: the content (mass%) of each element) reaches≤0.09% is heated to≥1,000°C, is hot-rolled so as to be finished at≥900°C, is coiled at≥650°C, is subjected to hot rolled sheet annealing and pickling treatment, is cold-rolled at a draft of≤90%, so as to be a cold-rolled sheet, and is thereafter subjected to continuous annealing at an annealing temperature of 800 to 900°C. In this way, the cold rolled stainless steel sheet having a ferrite single structure with a ferrite grain size of≥10μm in which Cr carbonitride of≤50 pieces per ferrite grain is dispersedly precipitated, and having excellent ductility can be obtained. COPYRIGHT: (C)2007,JPO&INPIT
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