The present invention relates to a method for the manufacture of a coated steel sheet comprising the following successive steps: A. the coating of the steel sheet with a first coating consisting of nickel and having a thickness between 600 nm and 1400 nm, the steel sheet having the following composition in weight: 0.10<C<0.40%, 1.5<Mn<3.0%, 0.7<Si<3.0%, 0.05<Al<1.0%, 0.75<(Si+Al)<3.0%, and on a purely optional basis, one or more elements such as Nb≤0.5%, B≤0.010%, Cr≤1.0%, Mo≤0.50%, Ni≤1.0%, Ti≤0.5%, the remainder of the composition making up of iron and inevitable impurities resulting from the elaboration, B. the recrystallization annealing at a temperature between 820 to 1200° C., C. the coating with a second coating based on zinc not comprising nickel.

Provided herein is a dual-phase stainless steel having excellent carbon dioxide corrosion resistance, excellent sulfide stress corrosion cracking resistance, and excellent sulfide stress cracking resistance. The dual-phase stainless steel contains, in mass %, C: 0.03% or less, Si: 1.0% or less, Mn: 0.10 to 1.5%, P: 0.030% or less, S: 0.005% or less, Cr: 20.0 to 30.0%, Ni: 5.0 to 10.0%, Mo: 2.0 to 5.0%, Cu: 2.0 to 6.0%, N: less than 0.07%, and the balance Fe and unavoidable impurities, and has a structure that is 20 to 70% austenite phase, and 30 to 80% ferrite phase in terms of a volume fraction.

Provided herein is a dual-phase stainless steel having excellent carbon dioxide corrosion resistance, excellent sulfide stress corrosion cracking resistance, and excellent sulfide stress cracking resistance. The dual-phase stainless steel contains, in mass %, C: 0.03% or less, Si: 1.0% or less, Mn: 0.10 to 1.5%, P: 0.030% or less, S: 0.005% or less, Cr: 20.0 to 30.0%, Ni: 5.0 to 10.0%, Mo: 2.0 to 5.0%, Cu: 2.0 to 6.0%, N: less than 0.07%, and the balance Fe and unavoidable impurities, and has a structure that is 20 to 70% austenite phase, and 30 to 80% ferrite phase in terms of a volume fraction.

The entirety or a part of this hot stamped product includes, as a chemical composition, by mass %, C: 0.001% or more and less than 0.080%, Si: 2.50% or less, Mn: 0.01% or more and less than 0.50%, P: 0.200% or less, S: 0.0200% or less, sol.Al: 0.001% to 2.500%, N: 0.0200% or less, Cr: 0.30% or more and less than 2.00%, and a remainder: Fe and impurities, in which a metallographic structure contains, by vol %, ferrite: more than 60.0%, martensite: 0% or more and less than 10.0%, and bainite: 0% or more and less than 20.0%, a tensile strength is less than 700 MPa, and ΔTS, which is a decrease in the tensile strength after a heat treatment at 170° C. for 20 minutes, is 100 MPa or less.

The entirety or a part of this hot stamped product includes, as a chemical composition, by mass %, C: 0.001% or more and less than 0.080%, Si: 2.50% or less, Mn: 0.01% or more and less than 0.50%, P: 0.200% or less, S: 0.0200% or less, sol.Al: 0.001% to 2.500%, N: 0.0200% or less, Cr: 0.30% or more and less than 2.00%, and a remainder: Fe and impurities, in which a metallographic structure contains, by vol %, ferrite: more than 60.0%, martensite: 0% or more and less than 10.0%, and bainite: 0% or more and less than 20.0%, a tensile strength is less than 700 MPa, and ΔTS, which is a decrease in the tensile strength after a heat treatment at 170° C. for 20 minutes, is 100 MPa or less.

There is provided a hot-stamped member or a steel sheet for hot stamping having a chemical composition including, in mass %, C: 0.25% or more and 0.55% or less, Si: 0.001% or more and 2.0% or less, Mn: 0.3% or more and 3.0% or less, P: 0.02% or less, S: 0.003% or less, Al: 0.005% or more and 1.0% or less, Cr: 0% or more and 1.0% or less, Mo: 0% or more and 1.0% or less, N: 0.02% or less, Ca: 0% or more and 0.0010% or less, B: 0.0005% or more and 0.01% or less, one or two or more selected from the group consisting of Ti: 0.005% or more and 0.5% or less, Nb: 0.005% or more and 0.5% or less, V: 0.005% or more and 0.5% or less, and Zr: 0.005% or more and 0.5% or less, and Ni+Cu+Sn: 0% or more and 2% or less, and a remainder consisting of Fe and impurities.

There is provided a hot-stamped member or a steel sheet for hot stamping having a chemical composition including, in mass %, C: 0.25% or more and 0.55% or less, Si: 0.001% or more and 2.0% or less, Mn: 0.3% or more and 3.0% or less, P: 0.02% or less, S: 0.003% or less, Al: 0.005% or more and 1.0% or less, Cr: 0% or more and 1.0% or less, Mo: 0% or more and 1.0% or less, N: 0.02% or less, Ca: 0% or more and 0.0010% or less, B: 0.0005% or more and 0.01% or less, one or two or more selected from the group consisting of Ti: 0.005% or more and 0.5% or less, Nb: 0.005% or more and 0.5% or less, V: 0.005% or more and 0.5% or less, and Zr: 0.005% or more and 0.5% or less, and Ni+Cu+Sn: 0% or more and 2% or less, and a remainder consisting of Fe and impurities.

Provided is a ferritic stainless steel in which cracking is unlikely to be caused in the vicinity of a weld zone by the stress due to expansion, contraction, and deformation due to the thermal effect of welding in the case of performing welding after deep drawing and which is excellent in corrosion resistance in the vicinity of the weld zone. The ferritic stainless steel has a composition containing C: 0.001% to 0.020%, Si: 0.01% to 0.30%, Mn: 0.01% to 0.50%, P: 0.04% or less, S: 0.01% or less, Cr: 18.0% to 24.0%, Ni: 0.01% to 0.40%, Mo: 0.30% to 3.0%, Al: 0.01% to 0.15%, Ti: 0.01% to 0.50%, Nb: 0.01% to 0.50%, V: 0.01% to 0.50%, Co: 0.01% to 6.00%, B: 0.0002% to 0.0050%, and N: 0.001% to 0.020% on a mass basis, the remainder being Fe and inevitable impurities. The composition satisfies 0.30%≤Ti+Nb+V≤0.60%.

Provided is a ferritic stainless steel in which cracking is unlikely to be caused in the vicinity of a weld zone by the stress due to expansion, contraction, and deformation due to the thermal effect of welding in the case of performing welding after deep drawing and which is excellent in corrosion resistance in the vicinity of the weld zone. The ferritic stainless steel has a composition containing C: 0.001% to 0.020%, Si: 0.01% to 0.30%, Mn: 0.01% to 0.50%, P: 0.04% or less, S: 0.01% or less, Cr: 18.0% to 24.0%, Ni: 0.01% to 0.40%, Mo: 0.30% to 3.0%, Al: 0.01% to 0.15%, Ti: 0.01% to 0.50%, Nb: 0.01% to 0.50%, V: 0.01% to 0.50%, Co: 0.01% to 6.00%, B: 0.0002% to 0.0050%, and N: 0.001% to 0.020% on a mass basis, the remainder being Fe and inevitable impurities. The composition satisfies 0.30%≤Ti+Nb+V≤0.60%.

A high-strength galvanized steel sheet includes a steel sheet having a chemical composition containing a predetermined component element, a mass ratio of a content of Si to a content of Mn in the steel (Si/Mn) being 0.1 or more and less than 0.2, and the balance: Fe and incidental impurities, and a steel structure in which an average grain size of inclusions containing at least one of Al, Si, Mg, and Ca and existing in an area extending from a surface to a position of ⅓ of a sheet thickness is 50 μm or less, and an average nearest distance between ones of the inclusions is 20 μm or more; and a galvanized layer provided on a surface of the steel sheet, in which an amount of diffusible hydrogen contained in the steel is less than 0.25 mass ppm, and a tensile strength is 1100 MPa or more.