Patent application number | Description | Published |
20120152411 | HIGH-STRENGTH GALVANIZED STEEL SHEET AND METHOD OF MANUFACTURING THE SAME - Provided is a galvanized steel sheet having a tensile strength of 770 MPa or more including a steel sheet portion, and a plated layer formed on the surface of the steel sheet portion, in which the plated layer is a galvanized plated layer or an galvannealed plated layer, the steel sheet portion has a soft layer that directly adjoins the interface with the plated layer and an inside layer that is other than the soft layer, the thickness D of soft layer is 0.001% to 5% of thickness t of the steel sheet portion, and, when the hardness of the soft layer measured by nano-indentation method is indicated by H1, and the representative hardness of the steel sheet portion measured by the nano-indentation method is indicated by Ha in cross section that goes along the thickness direction of the steel sheet portion, H1 is 5% to 75% of Ha. | 06-21-2012 |
20120282487 | HIGH-STRENGTH STEEL SHEET HAVING EXCELLENT PROCESSABILITY AND PAINT BAKE HARDENABILITY, AND METHOD FOR PRODUCING OF HIGH-STRENGTH STEEL SHEET - The high-strength steel sheet includes, by mass %: C: 0.01% to 0.10%; Si: 0.15% or less; Mn: 0.80% to 1.80%; P: 0.10% or less; S: 0.015% or less; Al: 0.10% to 0.80%; Cr: 0.01% to 1.50%; N: 0.0100% or less; and a balance consisting of iron and inevitable impurities, in which a metallic structure is composed of ferrite and a hard second phase, the area fraction of the ferrite is 80% or more, the area fraction of the hard second phase is 1% to 20%, the fraction of unrecrystallized ferrite in the ferrite is less than 10%, the ferrite grain sizes are 5 μm to 20 μm, and the fraction of the ferrite crystal grains having an aspect ratio of 1.2 or less in the entire ferrite crystal grains is 60% or more. | 11-08-2012 |
20120328901 | HIGH TENSILE STEEL SHEET SUPERIOR IN FORMABILITY AND METHOD OF MANUFACTURING THE SAME - With regard to an Al content (%) and a Si content (%), a relation of a formula (A) is established, and an average value Y | 12-27-2012 |
20130273392 | HOT-DIP GALVANIZED STEEL SHEET AND MANUFACTURING METHOD THEREOF - A hot-dip galvanized steel sheet includes a steel sheet and a hot-dip galvanized layer arranged on the steel sheet, in which the Si content and the Al content by mass % of components of the steel sheet satisfy a relationship 0.510-17-2013 | |
20140342185 | COLD ROLLED STEEL SHEET AND METHOD FOR PRODUCING COLD ROLLED STEEL SHEET - A cold rolled steel sheet according to the present invention satisfies an expression of ( | 11-20-2014 |
20140370329 | COLD ROLLED STEEL SHEET AND MANUFACTURING METHOD THEREOF - When the amount of C, the amount of Si and the amount of Mn are respectively represented by [C], [Si] and [Mn] in unit mass %, the cold rolled steel sheet satisfies a relationship of (5×[Si]+[Mn])/[C]>10, the metallographic structure contains, by area ratio, 40% to 90% of a ferrite and 10% to 60% of a martensite, further contains one or more of 10% or less of a pearlite by area ratio, 5% or less of a retained austenite by volume ratio and 20% or less of a bainite by area ratio, the hardness of the martensite measured using a nanoindenter satisfies H20/H10<1.10 and σHM0<20, and TS×λ representing the product of TS that is a tensile strength and λ that is a hole expansion ratio is 50000 MPa·% or more. | 12-18-2014 |
20150050519 | HOT STAMPED STEEL AND METHOD FOR PRODUCING THE SAME - In a hot stamped steel, when [C] represents an amount of C (mass %), [Si] represents an amount of Si (mass %), and [Mn] represents an amount of Mn (mass %), an expression of 5×[Si]+[Mn])/[C]>10 is satisfied, a metallographic structure includes 80% or more of a martensite in an area fraction, and optionally, further includes one or more of 10% or less of a pearlite in an area fraction, 5% or less of a retained austenite in a volume ratio, 20% or less of a ferrite in an area fraction, and less than 20% of a bainite in an area fraction, TS×λ, which is a product of TS that is a tensile strength and λ that is a hole expansion ratio is 50000 MPa·% or more, and a hardness of the martensite measured with a nanoindenter satisfies H2/H1<1.10 and σHM<20. | 02-19-2015 |
20150225830 | COLD-ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING SAME, AND HOT-STAMP FORMED BODY - A cold-rolled steel sheet has a predetermined chemical composition, in which a structure before and after a hot-stamping includes ferrite: 30 area % to 90 area %, martensite: 0 area % or more and less than 20 area %, pearlite: 0 area % to 10 area %, retained austenite: 5 volume % to 20 volume %, and rest structure: bainite, a hardness of the retained austenite measured with a nano indenter before and after the hot-stamping satisfies relations of H2/H1<1.1 and σHM<20, and a relation of TS×El>20000 MPa.% is satisfied. | 08-13-2015 |