Patent
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
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In this paper, a high-strength steel sheet with a tensile strength in a range of 590 MPa or more, and a ratio between the strength and the yield strength is in the range of 0.85 or more.Abstract:
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 anda 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 1010 precipitates/mm3 or more, and a ratio (Hvs/Hvc) of a hardness (Hvs) at a depth of 10 [mu]m from a surface to a hardness (Hvc) ata center of a sheet thickness is in a range of 0.85 or more.read more
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Hot-rolled steel sheet
TL;DR: A hot-rolled steel sheet has a specified chemical composition and has such a steel structure that the area ratio of a ferrite is 5 to 50% as discussed by the authors, and the total area ratio for a martensite, a pearlite and a retained austenite is 5% or less.
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High-strength cold-rolled steel sheet and process for manufacturing same
Masafumi Azuma,Takayuki Nozaki,Chisato Wakabayashi,Koichi Sato,Hiroyuki Kawata,Nobuhiro Fujita +5 more
TL;DR: In this paper, a high-strength cold-rolled steel sheet has been shown to have an internal microstructure which contains 3 to 20% retained austenite in volume fraction.
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Cold-rolled steel sheet and method for producing cold-rolled steel sheet
TL;DR: In this paper, a cold rolled steel sheet according to the present invention satisfies an expression of (5 × [Si + [Mn]) / [C] > 11 when [C], represents an amount of C by mass, [Si] represents a amount of Si by mass%, and [Mm] represents the amount of Mn by mass.
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Thick-walled high-strength hot rolled steel sheet having excellent hydrogen induced cracking resistance and manufacturing method thereof
Kinya Nakagawa,Chikara Kami +1 more
TL;DR: In this paper, a method of manufacturing a high-strength hot-rolled steel sheet with bainitic ferrite phase and a bainite phase has been proposed, where the steel sheet has the structure formed of a baintitic ferrites phase or a bainsite phase.
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High-strength hot dip galvanized steel plate having excellent moldability, weak material anisotropy and ultimate tensile strength of 980 mpa or more, high-strength alloyed hot dip galvanized steel plate and manufacturing method therefor
TL;DR: In this paper, a hot-dip galvanized steel sheet has been described, which is a high-strength hotdip steel sheet having small material anisotropy and excellent formability with an ultimate tensile strength of 980 MPa or more.
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Hot rolled steel plate, cold rolled steel plate and hot dip galvanized steel plate being excellent in strain aging hardening characteristics, and method for their production
TL;DR: In this paper, the authors presented a steel sheet having a chemical composition comprising 0.15% or less C, 2.0% or more Si, 3.5% Cu, or one or more of Cr, Mo and W in a total amount of 2.
Patent
High yield ratio and high strength cold-rolled steel plate and high yield ratio and high strength galvanized steel plate excellent in weldability and ductility, and high yield ratio and high strength alloyed galvanized steel plate and its manufacturing method
TL;DR: In this paper, the authors proposed a high yield ratio and high strength hot-rolled steel plate having excellent weldability and ductility is a steel containing, by mass%, over 0.68 or more and less than 0.0040 of B and the balance of iron and inevitable impurities.
Patent
High-strength hot-dip galvanized steel sheet and its manufacturing method
TL;DR: In this paper, a hot-dip galvanized steel sheet with high strength and high drawability is provided, where a structure having the following characteristics is provided: ferrite phase of ≤10 μm average grain size and martensite phase of 30 to 90% volume fraction are contained.
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Cold rolled steel sheet suitable for warm forming and its production method
TL;DR: In this article, a cold-rolled steel sheet with a composition comprising of 0.040 to 0.20% C, ≤ 1.5% Si, 0.50 to 3.0% Mn, ≤ 0.10% P, ≤0.01% S, 0,01 to 0,5% Al, and the balance Fe with inevitable impurities, and in which ≥90% of the above V lies in a solid solution state.
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High strength hot rolled steel sheet excellent in bore expanding workability and method for production thereof
Motoo Satou,Tetsuo Soshiroda +1 more
TL;DR: A steel sheet which comprises, in % by mass, 0.05 to 0.15% of C, 1.50% or less (exclusive of 0 %) of Si and 0.5 to 2.2% of Ti is a steel sheet with fracture appearance transition temperature (vTrs) as determined in the impact test on the steel sheet of 0˚C or lower as discussed by the authors.