The invention relates to a process for producing an at least partly quenched and tempered sheet steel component, where the process comprises the following steps: providing a sheet steel, at least partly austenitizing the sheet steel at a temperature of at least Ac1, at least partly hardening the at least partly austenitized sheet steel to give an at least partly hardened sheet steel component, where the at least partly austenitized sheet steel is cooled to a temperature below Ms, at least partly annealing the at least partly hardened sheet steel component at a temperature of less than Ac1 for producing an at least partly quenched and tempered sheet steel component. A further subject of the invention is an at least partly quenched and tempered sheet steel component.

Disclosed in the present invention is a manufacturing method for a carbon steel and austenitic stainless-steel rolling clad plate, comprising the steps of: (1) obtaining a blank material of a carbon steel layer and a blank material of a stainless-steel layer; (2) assembling blank materials; (3) cladding and rolling; (4) cold rolling; (5) first annealing; and (6) second annealing. The carbon steel and austenitic stainless-steel rolling clad plate has two unique annealing processes, so that the clad plate has the performance advantages of the austenitic stainless-steel and the carbon steel. In addition, further disclosed in the present invention is a carbon steel and austenitic stainless-steel rolling clad plate manufactured by this method.

Disclosed in the present invention is a manufacturing method for a carbon steel and austenitic stainless-steel rolling clad plate, comprising the steps of: (1) obtaining a blank material of a carbon steel layer and a blank material of a stainless-steel layer; (2) assembling blank materials; (3) cladding and rolling; (4) cold rolling; (5) first annealing; and (6) second annealing. The carbon steel and austenitic stainless-steel rolling clad plate has two unique annealing processes, so that the clad plate has the performance advantages of the austenitic stainless-steel and the carbon steel. In addition, further disclosed in the present invention is a carbon steel and austenitic stainless-steel rolling clad plate manufactured by this method.

The present invention provides wear-resistant steel which has high hardness while having wear resistance and high impact toughness at low temperature, and a manufacturing method therefor.

This steel sheet has a specific chemical composition, the tensile strength is 1300 MPa or more, the ratio (R/t) of the limit bend radius to the sheet thickness is less than 3.5, when a depth position of 30 μm from the surface in the sheet thickness direction is defined as a position A and a depth position of ¼ of the sheet thickness from the surface in the sheet thickness direction is defined as a position B, the number density of AIN at the position A is 3000 pieces/mm.sup.2 or more and 6000 pieces/mm.sup.2 or less, a metallographic structure at the position B includes 90% or more of martensite by volume percentage, and the hardness at the position A is 1.20 times or higher than the hardness at the position B.

Disclosed is a duplex ferritic austenitic stainless steel of 40-60 volume % ferrite and 40-60 volume % austenite, with improved cold workability and impact toughness. It contains less than 0.07% carbon (C), 0.1-2.0% silicon (Si), 3-5% manganese (Mn), 19-23% chromium (Cr), 1.1-1.9% nickel (Ni), 1.1-3.5% copper (Cu), 0.18-0.30% nitrogen (N), optionally molybdenum (Mo) and/or tungsten (W) according to the formula (Mo+½W)<1.0%. It optionally contains 0.001-0.005% boron (B), up to 0.03% of each of cerium (Ce) and/or calcium (Ca), with the balance being iron (Fe) and impurities where the chromium equivalent (Cr.sub.eq) and the nickel equivalent (Ni.sub.eq): 20<Cr.sub.eq<24.5 and Ni.sub.eq>10, where Cr.sub.eq=Cr+1.5Si+Mo+2Ti+0.5Nb Ni.sub.eq=Ni+0.5Mn+30(C+N)+0.5(Cu+Co).

Disclosed is a duplex ferritic austenitic stainless steel of 40-60 volume % ferrite and 40-60 volume % austenite, with improved cold workability and impact toughness. It contains less than 0.07% carbon (C), 0.1-2.0% silicon (Si), 3-5% manganese (Mn), 19-23% chromium (Cr), 1.1-1.9% nickel (Ni), 1.1-3.5% copper (Cu), 0.18-0.30% nitrogen (N), optionally molybdenum (Mo) and/or tungsten (W) according to the formula (Mo+½W)<1.0%. It optionally contains 0.001-0.005% boron (B), up to 0.03% of each of cerium (Ce) and/or calcium (Ca), with the balance being iron (Fe) and impurities where the chromium equivalent (Cr.sub.eq) and the nickel equivalent (Ni.sub.eq): 20<Cr.sub.eq<24.5 and Ni.sub.eq>10, where Cr.sub.eq=Cr+1.5Si+Mo+2Ti+0.5Nb Ni.sub.eq=Ni+0.5Mn+30(C+N)+0.5(Cu+Co).

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.

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.