Abstract: A high-strength cold-rolled steel sheet has a composite structure containing 0.15 to 0.25% by mass of C, 1.8 to 3.0% by mass of Mn, and 0.0003 to 0.0050% by mass of B, and having a ferrite volume fraction of 20% to 50%, a retained austenite volume fraction of 7% to 20%, a martensite volume fraction of 1% to 8%, and the balance containing bainite and tempered martensite, and in the composite structure, ferrite has an average crystal grain diameter of 5 ?m or less, retained austenite has an average crystal grain diameter of 0.3 to 2.0 ?m and an aspect ratio of 4 or more, martensite has an average crystal grain diameter of 2 ?m or less, a metal phase containing both bainite and tempered martensite has an average crystal grain diameter of 7 ?m or less, the ratio of the volume fraction of tempered martensite to the volume fraction of a metal structure other than ferrite is 0.60 to 0.85, and the average C concentration in retained austenite is 0.65% by mass or more.

Abstract: A high-yield-ratio, high-strength cold-rolled steel sheet has a composition containing, in terms of % by mass, C: 0.13% to 0.25%, Si: 1.2% to 2.2%, Mn: 2.0% to 3.2%, P: 0.08% or less, S: 0.005% or less, Al: 0.01% to 0.08%, N: 0.008% or less, Ti: 0.055% to 0.130%, and the balance being Fe and unavoidable impurities. The steel sheet has a microstructure that contains 2% to 15% of ferrite having an average crystal grain diameter of 2 um or less in terms of volume fraction, 5 to 20% of retained austenite having an average crystal grain diameter of 0.3 to 2.0 ?m in terms of volume fraction, 10% or less (including 0%) of martensite having an average grain diameter of 2 ?m or less in terms of volume fraction, and the balance being bainite and tempered martensite, and the bainite and the tempered martensite having an average crystal grain diameter of 5 ?m or less.

Abstract: A hot rolled steel sheet has a chemical composition including, by mass %, C: 0.060% to 0.120%; Si: 0.10% to 0.70%; Mn: 1.00% to 1.80%; P: 0.10% or less; S: 0.010% or less; Al: 0.01% to 0.10%; N: 0.010% or less; Nb: 0.010% to 0.100%, wherein Nb is contained so that content of solute Nb is 5% or more relative to the total Nb content; the balance being Fe and incidental impurities. The hot rolled steel sheet has a microstructure containing ferrite of not more than 15 ?m in average crystal grain diameter by a volume fraction of not less than 75%, the balance being low-temperature-induced phases. The hot rolled steel sheet can be suitably utilized for manufacturing a cold rolled steel sheet or hot-dip galvanized steel sheet having a tensile strength of 590 MPa or more, excellent in material homogeneity and capable of giving excellent cold rolling property.

Abstract: A high-strength cold-rolled steel sheet having good ductility, hole expandability, and delayed fracture resistance and being excellent in material homogeneity. The steel sheet has a chemical composition containing, in mass %, C: 0.15 to 0.25%, Si: 1.2 to 2.2%, Mn: 1.7 to 2.5%, P: 0.05% or less, S: 0.005% or less, Al: 0.01 to 0.10%, N: 0.006% or less, Ti: 0.003 to 0.030%, B: 0.0002 to 0.0050%, and Fe and inevitable impurities. The steel sheet has a microstructure that includes ferrite having an average crystal grain diameter of 4 ?m or less at a volume fraction of 5 to 20%, retained austenite at a volume fraction of 5% or less, including 0%, and tempered martensite at a volume fraction of 80 to 95%. Additionally, the mean free path of the ferrite is 3.0 to 7.5 ?m.

Abstract: A high-strength cold-rolled steel sheet has a chemical composition containing, by mass %, C: 0.15% or more and 0.30% or less, Si: 0.8% or more and 2.4% or less, Mn: 2.4% or more and 3.5% or less, P: 0.08% or less, S: 0.005% or less, Al: 0.01% or more and 0.08% or less, N: 0.010% or less, Ti: 0.002% or more and 0.05% or less, B: 0.0002% or more and 0.0050% or less, and the balance being Fe and inevitable impurities, a microstructure including ferrite having an average grain diameter of 3 ?m or less and a volume fraction of 5% or less (including 0%), retained austenite having a volume fraction of 10% or more and 20% or less, martensite having an average grain diameter of 4 ?m or less and a volume fraction of 20% or less (including 0%), and the balance including bainite and/or tempered martensite.

Abstract: A switching unit of an embodiment includes a first switching element of normally-on type, a second switching element of normally-off type having a non-reference potential side conductive terminal connected to a reference potential side conductive terminal of the first switching element, a series capacitor connected between a conduction control terminal of the first switching element and a conduction control terminal of the second switching element, and a diode having an anode connected to the conduction control terminal of the first switching element and a cathode connected to a common junction of the first switching element and the second switching element.

Abstract: Provided is a bake-hardening galvanized steel sheet which can preferably be used for, for example, automotive outer panels, which has a bake hardenability and corrosion resistance, which has good press formability, and with which a blister defect does not occur when a galvanizing treatment is performed, despite being manufactured at low cost by using low-carbon steel which can be comparatively easily manufactured. The steel sheet is a bake-hardening galvanized steel sheet having a base steel sheet and a coating layer formed on the base steel sheet, the base steel sheet having a specified chemical composition and a metallographic structure including a ferrite phase and a cementite phase, in which an average ferrite grain diameter is controlled to be 10 ?m or more and 30 ?m or less, and in which the surface area of the interface between ferrite and cementite per unit volume is controlled to be 1.0/mm or more and 10.

Abstract: A steel sheet includes a microstructure containing a volume fraction of 20% to 55% of ferrite having an average grain size of 7 ?m or less, a volume fraction of 5% to 15% of retained austenite, a volume fraction of 0.5% to 7% of martensite having an average grain size of 4 ?m or less, and a structure composed of bainite and/or tempered martensite and having an average grain size of 6 ?m or less, and a difference in nano-hardness between ferrite and the structure composed of bainite and/or tempered martensite being 3.5 GPa or less and a difference in nano-hardness between the structure composed of bainite and/or tempered martensite and martensite being 2.5 GPa or less.

Abstract: A high-strength cold-rolled steel sheet has a composition and a microstructure. The microstructure comprises: ferrite having an average grain size of 5 um or less and a volume fraction of 3% to 20%, retained austenite having a volume fraction of 5% to 20%, and martensite having a volume fraction of 5% to 20%, the remainder being bainite and/or tempered martensite. The total number of retained austenite with a grain size of 2 ?m or less, martensite with a grain size of 2 ?m or less, or a mixed phase thereof is 150 or more per 2,000 ?m2 of a thickness cross section parallel to the rolling direction of the steel sheet.

Abstract: According to one embodiment, a semiconductor device includes first to fourth circuit substrates. Each of the first to fourth circuit substrates includes a switching device. The first circuit substrate includes a first terminal unit and a second terminal unit set to a potential lower than a potential of the first terminal unit. The third circuit substrate includes a fifth terminal unit and a sixth terminal unit set to a potential lower than a potential of the fifth terminal unit. The first circuit substrate overlaps the third circuit substrate. The second circuit substrate overlaps the fourth circuit substrate. A direction from the first terminal unit toward the second terminal unit is reversely oriented with respect to a direction from the fifth terminal unit toward the sixth terminal unit.

Abstract: A method of manufacturing a galvanized steel sheet includes a two-stage temperature raising process which includes: primary heating the sheet from 200° C. to an intermediate temperature of 500 to 800° C. at a primary average heating rate of 5 to 50° C./second at an excess air ratio of 1.10 to 1.20 maintained up to the intermediate temperature; secondary heating the sheet from the intermediate temperature to an annealing temperature of 730 to 900° C. at a secondary average heating rate of 0.1 to 10° C./second at an excess air ratio of less than 1.10 maintained up to the annealing temperature; holding the sheet to the annealing temperature for 10 to 500 seconds; cooling the sheet to 450 to 550° C. at an average cooling rate of 1 to 30° C./second; and subjecting the sheet to a galvanizing process and, optionally, an alloying process.

Abstract: A high strength cold rolled steel sheet with a low yield ratio has a chemical composition containing C: 0.05% to 0.10%, Si: 0.6% to 1.3%, Mn: 1.4% to 2.2%, P: 0.08% or less, S: 0.010% or less, Al: 0.01% to 0.08%, N: 0.010% or less, and the remainder being Fe and incidental impurities, on a percent by mass basis, and a microstructure in which the average grain size of ferrite is 15 ?m or less, the volume fraction of ferrite is 70% or more, the volume fraction of bainite is 3% or more, the volume fraction of retained austenite is 4% to 7%, the average grain size of martensite is 5 ?m or less, and the volume fraction of martensite is 1% to 6%, wherein the average C concentration (percent by mass) in the retained austenite is 0.30% to 0.70%, yield ratio is 64% or less, and the tensile strength is 590 MPa or more.

Abstract: A method for manufacturing an ultra high strength member includes heating a steel sheet at a first heating temperature within a temperature range of 700 to 1000° C.; forming the steel sheet into a shape of a member at the first heating temperature and simultaneously cooling the steel sheet; after completion of the cooling, shear punching the steel sheet into a desired shape to obtain an ultra high strength member; and after the shear punching, subjecting the ultra high strength member to a first heat treatment including heating the ultra high strength member at second heating temperature within a temperature range of 100° C. or higher, but lower than 300° C. and retaining the member at the second heating temperature for 1 second to 60 minutes, wherein the resulting ultra high strength member has a tensile strength of 1180 MPa or more.

Abstract: According to one embodiment, a semiconductor device includes first to fourth circuit substrates. Each of the first to fourth circuit substrates includes a switching device. The first circuit substrate includes a first terminal unit and a second terminal unit set to a potential lower than a potential of the first terminal unit. The third circuit substrate includes a fifth terminal unit and a sixth terminal unit set to a potential lower than a potential of the fifth terminal unit. The first circuit substrate overlaps the third circuit substrate. The second circuit substrate overlaps the fourth circuit substrate. A direction from the first terminal unit toward the second terminal unit is reversely oriented with respect to a direction from the fifth terminal unit toward the sixth terminal unit.

Abstract: A high-strength cold-rolled steel sheet having high chemical convertibility and a tensile strength of 590 MPa or more and a method for producing such a steel sheet are provided. The steel sheet contains, in terms of percent by mass, C: 0.05 to 0.3%, Si: 0.6 to 3.0%, Mn: 1.0 to 3.0%, P: 0.1% or less, S: 0.05% or less, Al: 0.01 to 1%, N: 0.01% or less, and the balance being Fe and unavoidable impurities. The coverage ratio of reduced iron on a steel sheet surface is 40% or more. In order to produce such a steel sheet, an oxidation treatment is performed after cold rolling. Subsequently, annealing is conducted in a furnace in a 1 to 10 vol % H2+balance N2 gas atmosphere with a dew point of ?25° C. or less.

Abstract: Provided is a hot-rolled steel sheet that has a chemical composition including, by mass %: C: 0.060% to 0.150%; Si: 0.15% to 0.70%; Mn: 1.00% to 1.90%; P: 0.10% or less; S: 0.010% or less; Al: 0.01% to 0.10%; N: 0.010% or less; Nb: 0.010% to 0.100%; and the balance including Fe and incidental impurities. The hot-rolled steel sheet has a microstructure containing ferrite of 18 ?m or less in average grain size by a volume fraction of at least 75% and pearlite of at least 2 ?m in average grain size by a volume fraction of at least 5%, the balance being low-temperature-induced phases, the pearlite having a mean free path of at least 5.0 ?m.

Abstract: A high strength cold rolled steel sheet has a chemical composition including, by mass %, C: 0.06 to 0.13%, Si: 1.2 to 2.3%, Mn: 0.6 to 1.6%, P: not more than 0.10%, S: not more than 0.010%, Al: 0.01 to 0.10% and N: not more than 0.010%, the balance comprising Fe and inevitable impurities. The steel sheet includes a microstructure containing not less than 90% in terms of volume fraction of ferrite with an average grain diameter of less than 20 ?m and 1.0 to 10% in terms of volume fraction of pearlite with an average grain diameter of less than 5 ?m. The ferrite has an average Vickers hardness of not less than 130. The steel sheet has a yield ratio of not less than 65% and a tensile strength of not less than 590 MPa.

Abstract: A hot rolled steel sheet has a chemical composition including, by mass %, C: 0.060% to 0.120%; Si: 0.10% to 0.70%; Mn: 1.00% to 1.80%; P: 0.10% or less; S: 0.010% or less; Al: 0.01% to 0.10%; N: 0.010% or less; Nb: 0.010% to 0.100%, wherein Nb is contained so that content of solute Nb is 5% or more relative to the total Nb content; the balance being Fe and incidental impurities. The hot rolled steel sheet has a microstructure containing ferrite of not more than 15 ?m in average crystal grain diameter by a volume fraction of not less than 75%, the balance being low-temperature-induced phases. The hot rolled steel sheet can be suitably utilized for manufacturing a cold rolled steel sheet or hot-dip galvanized steel sheet having a tensile strength of 590 MPa or more, excellent in material homogeneity and capable of giving excellent cold rolling property.

Abstract: The present invention provides a pneumatic radial tire for a passenger vehicle, having: a cross sectional width SW and an outer diameter OD controlled under an appropriate SW-OD relationship; and an optimized configuration of a crown portion thereof.

Abstract: A high strength galvanized steel sheet including all in mass %, C: 0.05% to <0.12%, Si: 0.35% to <0.80%, Mn: 2.0 to 3.5%, P: 0.001 to 0.040%, S: 0.0001 to 0.0050%, Al: 0.005 to 0.1%, N: 0.0001 to 0.0060%, Cr: 0.01% to 0.5%, Ti: 0.010 to 0.080%, Nb: 0.010 to 0.080%, and B: 0.0001 to 0.0030%, optionally one or more of Mo: 0.01 to 0.15%, Ca: 0.0001 to 0.0050%, REM: 0.0001 to 0.1%, and Sb: 0.0001 to 0.1%, and Fe and unavoidable impurities as the balance, has a microstructure containing a ferrite phase with a volume fraction in a range of 20 to 70% and an average grain diameter equal to or smaller than 5 ?m, and has a galvanized layer on a surface thereof at a coating weight (per side) of 20 to 150 g/m2.