Abstract: 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 ?m is 10.0% or more.

Abstract: 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 pm is 10.0% or more.

Abstract: A hot rolled steel sheet consisting of, in mass %, C: 0.05% to 0.15%, Si: 0% to 0.2%, Al: 0.5% to 3.0%, Mn: 1.2% to 2.5%, P: 0.1% or less, S: 0.01% or less, N: 0.007% or less, Ti: 0.03% to 0.10%, Nb: 0.008% to 0.06%, V: 0% to 0.12%, one or more of Cr, Cu, Ni, and Mo: 0% to 2.0% in total, B: 0% to 0.005%, one or more of Ca, Mg, La, and Ce: 0% to 0.01% in total, total amount of Si and Al: 0.8×(Mn?1)% or more, total amount of Ti and Nb: 0.04% to 0.14%, and the balance: Fe and impurities. In a structure of steel, a total area ratio of martensite and retained austenite is 3% to 20%, an area ratio of ferrite is 50% to 96%, and an area ratio of pearlite is 3% or less. In a superficial layer part, the thickness in a sheet thickness direction of a region in which a network-like oxide is present is less than 0.5 ?m, and a maximum tensile strength is 720 MPa or more.

Abstract: A steel sheet for a hot stamping member contains, as a chemical composition, 0.10 mass % to 0.35 mass % of C; 0.01 mass % to 1.0 mass % of Si; 0.3 mass % to 2.3 mass % of Mn; 0.01 mass % to 0.5 mass % of Al; limited to 0.03 mass % or less of P; limited to 0.02 mass % or less of S; limited to 0.1 mass % or less of N; and a balance consisting of Fe and unavoidable impurities, in which a standard deviation of diameters of iron carbides which are contained in a region from a surface to a ¼ thickness position of the steel sheet is less than or equal to 0.8 ?m.

Abstract: 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.

Abstract: A high strength steel sheet containing chemical components of, in mass %, C: 0.20 to 0.42%, Si: 0.06 to 0.5%, Mn: 0.2 to 2.2%, Cr: 0.1 to 2.5%, B: 0.0005 to 0.01%, O: 0.0020 to 0.020%, Al: 0.001 to 0.03%, Ti: 0.001 to 0.05%, N: 0.1% or less, P: 0.03% or less, S: 0.02% or less, and the balance: Fe and inevitable impurities. In steel, 5×103 pieces per mm2 or more to 1×105 pieces per mm2 or less of Mn oxides having a maximum length of 1 ?m or more to 5 ?m or less are present, and 1.7×102 pieces per mm2 or more to 5×103 pieces per mm2 or less of Mn—Si composite oxides having a short-axial length of 1 ?m or more and a longitudinal length of 10 ?m or less are present.

Abstract: A high strength steel sheet containing chemical components of, in mass %, C: 0.20 to 0.42%, Si: 0.06 to 0.5%, Mn: 0.2 to 2.2%, Cr: 0.1 to 2.5%, B: 0.0005 to 0.01%, O: 0.0020 to 0.020%, Al: 0.001 to 0.03%, Ti: 0.001 to 0.05%, N: 0.1% or less, P: 0.03% or less, S: 0.02% or less, and the balance: Fe and inevitable impurities. In steel, 5×103 pieces per mm2 or more to 1×105 pieces per mm2 or less of Mn oxides having a maximum length of 1 ?m or more to 5 ?m or less are present, and 1.7×102 pieces per mm2 or more to 5×103 pieces per mm2 or less of Mn—Si composite oxides having a short-axial length of 1 ?m or more and a longitudinal length of 10 ?m or less are present.

Abstract: A hot rolled steel sheet consisting of, in mass %, C: 0.05% to 0.15%, Si: 0% to 0.2%, Al: 0.5% to 3.0%, Mn: 1.2% to 2.5%, P: 0.1% or less, S: 0.01% or less, N: 0.007% or less, Ti: 0.03% to 0.10%, Nb: 0.008% to 0.06%, V: 0% to 0.12%, one or more of Cr, Cu, Ni, and Mo: 0% to 2.0% in total, B: 0% to 0.005%, one or more of Ca, Mg, La, and Ce: 0% to 0.01% in total, total amount of Si and Al: 0.8×(Mn?1)% or more, total amount of Ti and Nb: 0.04% to 0.14%, and the balance: Fe and impurities. In a structure of steel, a total area ratio of martensite and retained austenite is 3% to 20%, an area ratio of ferrite is 50% to 96%, and an area ratio of pearlite is 3% or less. In a superficial layer part, the thickness in a sheet thickness direction of a region in which a network-like oxide is present is less than 0.5 ?m, and a maximum tensile strength is 720 MPa or more.

Abstract: 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 ?m is 10.0% or more.

Abstract: 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.

Abstract: 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.

Abstract: A steel sheet for a hot stamping member contains, as a chemical composition, 0.10 mass % to 0.35 mass % of C; 0.01 mass % to 1.0 mass % of Si; 0.3 mass % to 2.3 mass % of Mn; 0.01 mass % to 0.5 mass % of Al; limited to 0.03 mass % or less of P; limited to 0.02 mass % or less of S; limited to 0.1 mass % or less of N; and a balance consisting of Fe and unavoidable impurities, in which a standard deviation of diameters of iron carbides which are contained in a region from a surface to a ¼ thickness position of the steel sheet is less than or equal to 0.8 ?m.

Abstract: A steel sheet for obtaining a member which is excellent in fatigue characteristics equal to ordinary high strength steel sheet of the same strength even if applying the hot stamping process and a method of production of the same are provided. Steel sheet for a hot stamped member which includes composition which contains, by mass %, C: 0.15 to 0.35%, Si: 0.01 to 1.0%, Mn: 0.3 to 2.3%, Al: 0.01 to 0.5%, and a balance of Fe and unavoidable impurities, and limit the impurities to P: 0.03% or less, S: 0.02% or less, and N: 0.1% or less, wherein that a standard error of Vicker's hardness at a position of 20 ?m from the steel sheet surface in the sheet thickness direction is 20 or less. This steel sheet is produced by a recrystallization-annealing step of a first stage of heating a cold rolled steel sheet, which is obtained by hot rolling steel containing the above composition and then cold rolling it, by an average heating rate of 8 to 25° C./sec from room temperature to 600 to 700° C.

Abstract: 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.

Abstract: A method of connecting a TAB tape to a semiconductor chip is disclosed which comprises the steps of preliminarily locating and fixing bumps at positions corresponding to a pattern of electrodes of the semiconductor chip to be connected; and bonding the bumps by thermocompression to the electrodes of the semiconductor chip and the leads of the TAB tape, respectively, so that each electrode of the semiconductor chip is electrically connected to the corresponding lead of the TAB tape through a corresponding one of the bumps. Also disclosed are a bump sheet and a bumped tape to be used in a method of connecting a TAB tape to a semiconductor chip.

Abstract: A method of bonding bumps to leads of a TAB tape comprises the steps of preparing a substrate which is provided with through-holes, each having a size which will not allow the bumps to pass therethrough, at positions corresponding to bonding positions of the leads of the TAB tape where the bumps are to be bonded; provisionally arranging the bumps at positions of the through-holes at one side of the substrate by reducing a pressure in another side of the substrate opposite to said one side thereof to such the bumps in said through-holes; disposing the substrate on which the bumps are provisionally arranged and said TAB tape in such a positional relationship that said bumps face to the bonding positions of the leads of said TAB tape; and bonding the provisionally arranged bumps to the leads at the bonding positions and an apparatus for arranging bumps in a positional relationship corresponding to bonding positions of leads of a TAB tape.