Patent classifications
Y10T428/12757
Coated Steel Strips, Coated Stamped Products and Methods
A pre-coated steel strip is provided. The steel strip includes a strip of base steel having a length, a width, a first side, and a second side. The length of the strip is at least 100 m and the width is at least 600 mm. An aluminum or an aluminum alloy pre-coating is on at least part of at least one of the first or second sides of the strip of base steel. A thickness t.sub.p of the pre-coating is from 20 to 33 micrometers at every location on at least one of the first or second sides. Processes, coated stamped products and land motor vehicles are also provided.
Method for producing an ultra high strength coated or not coated steel sheet and obtained sheet
A method for producing a cold rolled steel sheet having a tensile strength≥1470 MPa and a total elongation TE≥19%, the method comprising the steps of annealing at an annealing temperature AT≥Ac3 a non-treated steel sheet whose chemical composition contains in weight %: 0.34%≤C≤0.40%, 1.50%≤Mn≤2.30%, 1.50≤Si≤2.40%, 0%<Cr≤0.5%, 0%<Mo≤0.3%, 0.01%≤Al≤0.07%, the remainder being Fe and unavoidable impurities, quenching the annealed steel sheet by cooling it to a quenching temperature QT<Ms transformation point and between 150° C. and 250° C., and making a partitioning treatment by reheating the quenched steel sheet to a partitioning temperature PT between 350° C. and 420° C. and maintaining the steel sheet at this temperature during a partitioning time Pt between 15 seconds and 120 seconds.
Method for producing a ultra high strength coated or not coated steel sheet and obtained sheet
A method for producing a cold rolled steel sheet having a tensile strength ≥1470 MPa and a total elongation TE≥19%, the method comprising the steps of annealing at an annealing temperature AT≥Ac3 a non-treated steel sheet whose chemical composition contains in weight %: 0.34%≤C≤0.40%, 1.50%≤Mn≤2.30%, 1.50≤Si≤2.40%, 0<Cr≤0.5%, 0<Mo≤0.3%, 0.01%≤Al≤0.07%, the remainder being Fe and unavoidable impurities, quenching the annealed steel sheet by cooling it to a quenching temperature QT<Ms transformation point and between 150° C. and 250° C., and making a partitioning treatment by reheating the quenched steel sheet to a partitioning temperature PT between 350° C. and 420° C. and maintaining the steel sheet at this temperature during a partitioning time Pt between 15 seconds and 120 seconds.
METAL-COATED STEEL STRIP
An Al—Zn—Si—Mg alloy coated strip that has Mg.sub.2Si particles in the coating microstructure is disclosed. The distribution of Mg.sub.2Si particles is such that the surface of the coating has only a small proportion of Mg.sub.2Si particles or is at least substantially free of any Mg.sub.2Si particles.
METHOD FOR PRODUCING A ULTRA HIGH STRENGTH COATED OR NOT COATED STEEL SHEET AND OBTAINED SHEET
A method IS for producing a cold rolled steel sheet having a tensile strength ≥1470 MPa and a total elongation TE≥19%. The method includes the steps of annealing at an annealing temperature AT≥Ac3 a non-treated steel sheet whose chemical composition contains in weight %: 0.34%≤C≤0.40%, 1.50%≤Mn≤2.30%, 1.50≤Si≤2.40%, 0%<Cr≤0.7%, 0%≤Mo≤0.3%, 0.01%≤Al≤0.07%, the remainder being Fe and unavoidable impurities, quenching the annealed steel sheet by cooling it to a quenching temperature QT<Ms transformation point and between 150° C. and 250° C., and making a partitioning treatment by reheating the quenched steel sheet to a partitioning temperature PT between 350° C. and 420° C. and maintaining the steel sheet at this temperature during a partitioning time Pt between 15 seconds and 250 seconds.
High-strength hot-dip coated hot-rolled steel sheet and method for manufacturing the same
A high-strength hot-dip coated hot-rolled steel sheet excellent in terms of surface appearance quality and coating adhesiveness and a method for manufacturing. The method includes performing hot rolling followed by pickling on steel to form a pickled steel sheet, the steel having a chemical composition containing, by mass %, C: 0.02% or more and 0.30% or less, Si: 0.01% or more and 1.0% or less, Mn: 0.3% or more and 2.5% or less, P: 0.08% or less, S: 0.02% or less, Al: 0.001% or more and 0.20% or less, and Fe and inevitable impurities. The method further includes performing rolling with a rolling reduction ratio of 1% or more and 10% or less, and a hot-dip coating treatment. The obtained steel sheet has an arithmetic average roughness Ra of 2.0 μm or less on the surface of the steel sheet, and a tensile strength of 590 MPa or more.
HIGH-STRENGTH HOT-ROLLED COATED STEEL SHEET
The high-strength hot-rolled coated steel sheet includes a steel sheet having a chemical composition containing, by mass %, C: 0.03% to 0.09%, Si: 0.01% to 1.60%, Mn: 2.20% to 3.60%, P: 0.100% or less, S: 0.0100% or less, Ti: 0.05% to 0.18%, B: 0.0005% to 0.0050%, Al: 0.005% to 0.40%, N: 0.010% or less, and a balance of Fe and inevitable impurities, in which a CSM value expressed by the equation 33.8[% C][% Mn]+12.4[% Si]/[% Mn] is 3.3 to 12.0, and a steel microstructure containing bainite in an amount of 85% or more in terms of area fraction and martensite in an amount of 2.0% or more and 15.0% or less in terms of area fraction and includes a coating layer or an alloyed coating layer on a surface of the steel sheet.
Metal-coated steel strip
An Al—Zn—Si—Mg alloy coated strip that has Mg.sub.2Si particles in the coating microstructure is disclosed. The distribution of Mg.sub.2Si particles is such that the surface of the coating has only a small proportion of Mg.sub.2Si particles or is at least substantially free of any Mg.sub.2Si particles.
Coated steel strips, coated stamped products and methods
A pre-coated steel strip is provided. The steel strip includes a strip of base steel having a length, a width, a first side, and a second side. The length of the strip is at least 100 m and the width is at least 600 mm. An aluminum or an aluminum alloy pre-coating is on at least part of at least one of the first or second sides of the strip of base steel. A thickness t.sub.p of the pre-coating is from 20 to 33 micrometers at every location on at least one of the first or second sides. Processes, coated stamped products and land motor vehicles are also provided.
METHOD FOR PRODUCING HOT-ROLLED STEEL SHEET, METHOD FOR PRODUCING COLD-ROLLED FULL-HARD STEEL SHEET, AND METHOD FOR PRODUCING HEAT-TREATED SHEET
A method for producing a hot-rolled steel sheet, a method for producing a cold-rolled full-hard steel sheet, and a method for producing a heat-treated sheet are provided herein. The methods comprising hot rolling a steel material of a composition comprising, in mass %, C: 0.05 to 0.12%, Si: 0.80% or less, Mn: 1.30 to 2.10%, P: 0.001 to 0.050%, S: 0.005% or less, Al: 0.01 to 0.10%, N: 0.010% or less, one or more selected from Cr in an amount of 0.05 to 0.50%, and Mo in an amount of 0.05 to 0.50%, one or more selected from Ti in an amount of 0.01 to 0.10%, Nb in an amount of 0.01 to 0.10%, and V in an amount of 0.01 to 0.10%, and the balance Fe and unavoidable impurities.