Patent application number | Description | Published |
20110303328 | HIGH-STRENGTH PRESS HARDENED ARTICLE, AND MANUFACTURING METHOD THEREFOR - A high-strength quenched formed article has a zinc plating layer which is formed at a post-quenching formed steel sheet surface, and which contains 30 g/m | 12-15-2011 |
20120031528 | HIGH-STRENGTH STEEL SHEET, HOT-DIPPED STEEL SHEET, AND ALLOY HOT-DIPPED STEEL SHEET THAT HAVE EXCELLENT FATIGUE, ELONGATION, AND COLLISION CHARACTERISTICS, AND MANUFACTURING METHOD FOR SAID STEEL SHEETS - This high-strength steel sheet includes: in terms of percent by mass, 0.03 to 0.10% of C; 0.01 to 1.5% of Si; 1.0 to 2.5% of Mn; 0.1% or less of P; 0.02% or less of S; 0.01 to 1.2% of Al; 0.06 to 0.15% of Ti; and 0.01% or less of N; and contains as the balance, iron and inevitable impurities, wherein a tensile strength is in a range of 590 MPa or more, and a ratio between the tensile strength and a yield strength is in a range of 0.80 or more, a microstructure includes bainite at an area ratio of 40% or more and the balance being either one or both of ferrite and martensite, a density of Ti(C,N) precipitates having sizes of 10 nm or smaller is in a range of 10 | 02-09-2012 |
20120279620 | HIGH STRENGTH HOT-ROLLED STEEL PLATE EXHIBITING EXCELLENT ACID PICKLING PROPERTY, CHEMICAL CONVERSION PROCESSABILITY, FATIGUE PROPERTY, STRETCH FLANGEABILITY, AND RESISTANCE TO SURFACE DETERIORATION DURING MOLDING, AND HAVING ISOTROPIC STRENGTH AND DUCTILITY, AND METHOD FOR PRODUCING SAID HIGH STRENGTH HOT-ROLLED STEEL PLATE - This high strength hot-rolled steel sheet includes: in terms of percent by mass, C: 0.05 to 0.12%; Si: 0.8 to 1.2%; Mn: 1.6 to 2.2%; Al: 0.30 to 0.6%; P: 0.05% or less; S: 0.005% or less; and N: 0.01% or less, with the remainder being Fe and unavoidable impurities, wherein a microstructure includes specific ranges (in area %) of ferrite phases as well as martensite phases, and a maximum concentration of Al detected by a glow discharge emission spectroscopic analysis is in a range of 0.75 mass % or less in a region from a surface of the steel sheet to a thickness of 500 nm after being acid-pickled. | 11-08-2012 |
20130199676 | METHOD FOR MANUFACTURING HOT STAMPED BODY HAVING VERTICAL WALL AND HOT STAMPED BODY HAVING VERTICAL WALL - The present invention provides a method for manufacturing a hot stamped body having a vertical wall, the method including: a hot-rolling step; a coiling step; a cold-rolling step; a continuous annealing step; and a hot stamping step, in which the continuous annealing step includes a heating step of heating the cold-rolled steel sheet to a temperature range of equal to or higher than Ac | 08-08-2013 |
20130220490 | STEEL SHEET AND METHOD FOR MANUFACTURING STEEL SHEET - The present invention provides a steel sheet with chemical components including, by mass%, 0.18-0.35% of C, 1.0%-3.0% of Mn, 0.01%-1.0% of Si, 0.001%-0.02% of P, 0.0005%-0.01% of S, 0.001%-0.01% of N, 0.01%-1.0% of Al, 0.005%-0.2% of Ti, 0.0002%-0.005% of B, and 0.002%-2.0% of Cr, and the balance of Fe and inevitable impurities, wherein: by volume%, a fraction of the ferrite is 50% or more, and a fraction of a non-recrystallized ferrite is 30% or less; and Cr | 08-29-2013 |
20130292009 | METHOD FOR MANUFACTURING HOT STAMPED BODY AND HOT STAMPED BODY - The present invention provides a method for manufacturing a hot stamped body, the method including: a hot-rolling step; a coiling step; a cold-rolling step; a continuous annealing step; and a hot stamping step, in which the continuous annealing step includes a heating step of heating the cold-rolled steel sheet to a temperature range of equal to or higher than Ac | 11-07-2013 |
20140311631 | HIGH-STRENGTH STEEL SHEET, HOT-DIPPED STEEL SHEET, AND ALLOY HOT-DIPPED STEEL SHEET THAT HAVE EXCELLENT FATIGUE, ELONGATION, AND COLLISION CHARACTERISTICS, AND MANUFACTURING METHOD FOR SAID STEEL SHEETS - This high-strength steel sheet includes: in terms of percent by mass, 0.03 to 0.10% of C; 0.01 to 1.5% of Si; 1.0 to 2.5% of Mn; 0.1% or less of P; 0.02% or less of S; 0.01 to 1.2% of Al; 0.06 to 0.15% of Ti; and 0.01% or less of N; and contains as the balance, iron and inevitable impurities, wherein a tensile strength is in a range of 590 MPa or more, and a ratio between the tensile strength and a yield strength is in a range of 0.80 or more, a microstructure includes bainite at an area ratio of 40% or more and the balance being either one or both of ferrite and martensite, a density of Ti(C,N) precipitates having sizes of 10 nm or smaller is in a range of 10 | 10-23-2014 |
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 |
20140360631 | HIGH STRENGTH HOT-ROLLED STEEL PLATE EXHIBITING EXCELLENT ACID PICKLING PROPERTY, CHEMICAL CONVERSION PROCESSABILITY, FATIGUE PROPERTY, STRETCH FLANGEABILITY, AND RESISTANCE TO SURFACE DETERIORATION DURING MOLDING, AND HAVING ISOTROPIC STRENGTH AND DUCTILITY - This high strength hot-rolled steel sheet includes: in terms of percent by mass, C: 0.05 to 0.12%; Si: 0.8 to 1.2%; Mn: 1.6 to 2.2%; Al: 0.30 to 0.6%; P: 0.05% or less; S: 0.005% or less; and N: 0.01% or less, with the remainder being Fe and unavoidable impurities, wherein a microstructure includes specific ranges (in area %) of ferrite phases as well as martensite phases, and a maximum concentration of Al detected by a glow discharge emission spectroscopic analysis is in a range of 0.75 mass % or less in a region from a surface of the steel sheet to a thickness of 500 nm after being acid-pickled. | 12-11-2014 |
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 |
20150024237 | STEEL SHEET FOR HOT STAMPING, METHOD FOR PRODUCTION THEREOF, AND HOT STAMPING STEEL MATERIAL - A hot stamping steel material, which secures good hydrogen embrittlement resistance even when the steel sheet after hot stamping is subjected to processing leading to remaining of stress, such as piercing and which is easily practicable, wherein the steel sheet has the chemical composition of: C: 0.18 to 0.26%; Si: more than 0.02% and not more than 0.05%; Mn: 1.0 to 1.5%; P: 0.03% or less; S: 0.02% or less; Al: 0.001 to 0.5%; N: 0.1% or less; O: 0.001 to 0.02%; Cr: 0 to 2.0%; Mo: 0 to 1.0%; V: 0 to 0.5%; W: 0 to 0.5%; Ni: 0 to 5.0%; B: 0 to 0.01%; Ti: 0 to 0.5%; Nb: 0 to 0.5%; Cu: 0 to 1.0%; and balance: Fe and impurities, in terms of % by mass, the concentration of a Mn-containing inclusion is not less than 0.010% by mass and less than 0.25% by mass, and the number ratio of a Mn oxide to the inclusion having a maximum length of 1.0 to 4.0 μm is 10.0% or more. | 01-22-2015 |
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 |