Ferritic stainless steel sheet having excellent corrosion resistance and method of manufacturing the same

A method of manufacturing a ferritic stainless steel sheet having excellent corrosion resistance:

• hot rolling a material consisting of:
• C of 0.03% or less,
• Si of 1.0% or less,
• Mn of 0.5% or less,
• P of 0.04% or less,
• S of 0.02% or less,
• Al of 0.1% or less,
• Cr of 20.5% to 22.5%,
• Cu of 0.3% to 0.8%,
• Ni of 1.0% or less,
• Ti of 4×(C %+N %) to 0.35%,
• Nb of less than 0.01%,
• N of 0.03% or less,
• optionally at least one of 0.0002 to 0.002% of B, 0.01 to 0.5% of V or 0.01 to 0.5% of Zr, and
• C+N of 0.05% or less, and
• the remainder of the steel sheet being Fe and inevitable impurities, in which the following equation (1) is satisfied,
• 240+35×(Cr %−20.5)+280×{Ti %−4×(C %+N %)}≧280 (1),
• wherein C %, N %, Cr % and Ti % indicate the content of C, N, Cr and Ti (mass percent), respectively,
• into a hot-rolled sheet;
• continuously annealing the hot-rolled sheet into an annealed sheet at a temperature of 800 to 1000° C.;
• pickling the annealed sheet;
• cold-rolling the annealed sheet to form a cold-rolled sheet;
• and
• annealing and pickling the cold-rolled sheet in a high speed continuous annealing line for combined use with carbon steel such that the steel sheet has a pitting potential equivalent of 280 or more.

A ferritic stainless steel sheet having excellent corrosion resistance comprising:

• C of 0.03% or less,
• Si of 1.0% or less,
• Mn of 0.5% or less,
• P of 0.04% or less,
• S of 0.02% or less,
• Al of 0.1% or less,
• Cr of 20.5% to 22.5%,
• Cu of 0.3% to 0.8%,
• Ni of 1.0% or less,
• Ti of 4×(C %+N %) to 0.35%,
• Nb of less than 0.01%,
• N of 0.03% or less,
• optionally at least one of 0.0002 to 0.002% of B, 0.01 to 0.5% of V or 0.01 to 0.5% of Zr, and
• C+N of 0.05% or less, and
• the steel sheet having
• the remainder including Fe and inevitable impurities;
• wherein the following equation (1) is satisfied,
• 240+35×(Cr %−20.5)+280×{Ti %−4×(C %+N %)}≧280 (1),
• wherein C %, N %, Cr % and Ti % indicate the content (mass percent) of C, N, Cr and Ti, respectively, and the steel sheet has a pitting potential equivalent of 280 or more.

A method of manufacturing a ferritic stainless steel sheet having excellent corrosion resistance:

• hot rolling a material comprising:
• C of 0.03% or less,
• Si of 1.0% or less,
• Mn of 0.5% or less,
• P of 0.04% or less,
• S of 0.02% or less,
• Al of 0.1% or less,
• Cr of 20.5% to 22.5%,
• Cu of 0.3% to 0.8%,
• Ni of 1.0% or less,
• Ti of 4×(C %+N %) to 0.35%,
• Nb of less than 0.01%,
• N of 0.03% or less,
• optionally at least one of 0.0002 to 0.002% of B, 0.01 to 0.5% of V or 0.01 to 0.5% of Zr, and
• C+N of 0.05% or less, and
• the steel sheet having
• the remainder including Fe and inevitable impurities,
• in which the following equation (1) is satisfied,
• 240+35×(Cr %−20.5)+280×{Ti %−4×(C %+N %)}≧280 (1),
• wherein C %, N %, Cr % and Ti % indicate the content of C, N, Cr and Ti (mass percent), respectively,
• into a hot-rolled sheet;
• continuously annealing the hot-rolled sheet into an annealed sheet at a temperature of 800 to 1000° C.;
• pickling the annealed sheet;
• cold-rolling the annealed sheet to form a cold-rolled sheet;
• and
• annealing and pickling the cold-rolled sheet in a high speed continuous annealing line for combined use with carbon steel such that the steel sheet has a pitting potential equivalent of 280 or more.