Abstract: The present invention provides a “TRIP effect” cold-rolled and annealed steel sheet which has improved formability and weldability, strength between 780 and 900 MPa and elongation at fracture greater than 19%, the composition of which includes the following elements in percentages expressed by weight: 0.17%?C?0.25%, 1.5%?Mn?2%, 0.50%?Si?1%, 0.50%?Al?1.2%, whereby Si+Al?1.30%, the remainder of the composition including iron and the inevitable impurities resulting from processing. The microstructure of the sheet includes 65 to 85% ferrite and 15 to 35% islands of martensite and residual austenite. The average size of these islands of martensite and residual austenite is less than 1.3 micrometers and their shape factor is less than 3.

Abstract: This invention relates to a flux composition for treating a metal surface, comprising (a) more than 40 and less than 70 wt. % zinc chloride, (b) 10 to 30 wt. % ammonium chloride, (c) more than 6 and less than 30 wt. % of a set of at least two alkali metal chlorides including sodium chloride and potassium chloride, (d) from 0 to 2 wt. % lead chloride, and (e) from 0 to 15 wt. % tin chloride, provided that the KCl/NaCl weight ratio of said set of at least two alkali metal chlorides ranges from 2.0 to 8.0. This invention also relates to a fluxing bath comprising this flux composition dissolved in water for use in galvanizing processes, by batch or continuously, of metal articles such as iron or steel long products and flat products including wires, plates, coils, rods, reinforcing bars, tubes, strips and sheets.

Abstract: By first fluxing a steel long product with novel specific flux compositions, it is possible to continuously produce, more uniform, smoother and void-free galvanized coatings on such steel long products in a single hot dip galvanization step making use of zinc-aluminum alloys or zinc-aluminum-magnesium alloys with less than 95 wt. % zinc. This is achieved by providing specific amounts of lead chloride and tin chloride in a flux composition comprising (a) more than 40 and less than 70 weight % zinc chloride, (b) from 10 to 30 weight % ammonium chloride, (c) more than 6 and less than 30 weight % of a set of at least two alkali or alkaline earth metal chlorides.

Abstract: This invention relates to a flux composition for treating a metal surface prior to batch hot galvanizing in molten zinc-based alloys. The composition comprises (a) more than 40 and less than 70 wt. % zinc chloride, (b) 10 to 30 wt. % ammonium chloride, (c) more than 6 and less than 30 wt. % of a set of at least two alkali or alkaline earth metal halides, (d) from 0.1 to 2 wt. % lead chloride, and (e) from 2 to 15 wt. % tin chloride, provided that the combined amounts of lead chloride and tin chloride represent at least 2.5 wt. % of said composition. The invention further relates to a fluxing bath comprising this flux composition dissolved in water for use in galvanizing processes, by batch or continuously, of metal articles such as iron or steel long products and flat products, thus affording a protective coating layer with a thickness ranging from 5 to 30 ?m.

Abstract: By first fluxing a steel long product with novel specific flux compositions, it is possible to continuously produce, more uniform, smoother and void-free galvanized coatings on such steel long products in a single hot dip galvanization step making use of zinc-aluminum alloys or zinc-aluminum-magnesium alloys with less than 95 wt. % zinc. This is achieved by providing potassium and sodium chlorides in a KCl/NaCl weight ratio of at least 2.0 in a flux composition comprising (a) more than 40 and less than 70 weight % zinc chloride, (b) from 10 to 30 weight % ammonium chloride, (c) more than 6 and less than 30 weight % of a set of at least two alkali metal chlorides.

Abstract: Disclosed is a hot-dip galvannealed steel sheet that stably exhibits satisfactory phosphatability. It is a high-strength hot-dip galvannealed steel sheet which includes a base steel sheet and, arranged on at least one side thereof, an Fe—Zn alloyed galvanized layer. The base steel sheet contains 0.03% to 0.3% of carbon, 0.5% to 3.0% of silicon, and 0.5% to 3.5% of manganese, with the remainder including iron and inevitable impurities. The Fe—Zn alloyed galvanized layer has a concentration of silicon present as an oxide of [Si] (percent by mass) and a concentration of manganese present as an oxide of [Mn] (percent by mass), and these parameters satisfy the following conditions (1) and (2): [Si]?0.25??(1) [Mn]/[Si]?3.0??(2).

Abstract: The high-strength quenched formed body contains a layer, in which Zn is a major component and which is formed of Fe: 30% by mass or less, in an amount of 30 g/m2 or more on the surface of an after-quenching formed-body steel material, and accordingly is good in corrosion resistance. A quenched formed body is produced by quenching a zinc-plated steel material, which includes a zinc-plated layer which contains each of Al and Si having alloying-retarding function and readily-oxidizing function independently or compositely, in an amount of 0.15% by mass or more, after heating it to 800° C. or more and 950° C. or less in an oxidizing atmosphere of oxygen: 0.1% by volume or more.

Abstract: A galvannealed steel sheet obtained by subjecting a base steel sheet to hot-dip galvanization and then alloying the galvanization layer, the base steel sheet being obtained by hot rolling a specified steel. A method for producing the galvannealed steel sheet.

Abstract: Disclosed are heat-hardened steel with excellent crashworthiness and a method for manufacturing heat-hardenable parts using the same. The heat-hardened steel according to the invention comprises, based on wt %; C: 0.12-0.8%; Cr: 0.01-2%; Mo: 0.2% or less; B: 0.0005-0.08%; Ca: 0.01 or less; Sb: 1.0% or less; and Ti and/or Nb: 0.2%; and the reminder being Fe and inevitable impurities. In addition, the heat-treatment hardening steel satisfies anyone of following conditions i)-iv), wherein condition i) comprises Si: 0.5-3%; Mn: 1-10% and Al: 0.05-2%; condition ii) comprises Si: 1% or less; Mn: 0.5-5%; Al: 0.1-2.5%; and Ni: 0.01-8%; condition iii) comprises Si: 0.5-3%; Mn: 1-10%; Al: 0.1% or less; and Ni: 0.01-8%; and condition iv) comprises Si: 0.5-3%; Mn: 1-10%; Al: 0.1-2.5%; and Ni: 0.01-8%.

Abstract: A cold-rolled steel sheet satisfies that an average pole density of an orientation group of {100}<011> to {223}<110> is 1.0 to 5.0, a pole density of a crystal orientation {332}<113> is 1.0 to 4.0, a Lankford-value rC in a direction perpendicular to a rolling direction is 0.70 to 1.50, and a Lankford-value r30 in a direction making an angle of 30° with the rolling direction is 0.70 to 1.50. Moreover, the cold-rolled steel sheet includes, as a metallographic structure, by area %, a ferrite and a bainite of 30% to 99% in total and a martensite of 1% to 70%.

Abstract: A hot-pressed member includes a steel sheet, a Ni-diffusion region present in a surface layer of the steel sheet, and an intermetallic compound layer and a ZnO layer which are provided in order on the Ni-diffusion region, the intermetallic compound layer corresponding to a ? phase present in a phase equilibrium diagram of a Zn—Ni alloy, wherein a spontaneous immersion potential indicated in a 0.5 M NaCl aqueous air-saturated solution at 25° C.±5° C. is ?600 to ?360 mV based on a standard hydrogen electrode.

Abstract: The present invention provides a high corrosion resistance hot dip galvannealed steel material comprised of a Zn-based hot dip plated steel material achieving both a higher corrosion resistance of the plated layer itself by the added elements and sacrificial protection of iron metal by the plated layer or workability free of degradation caused of formation of intermetallic compounds by added elements, that is, a high corrosion resistance hot dip Zn plated steel material characterized in that an alloy plated layer containing Zn: 35 mass % or more, preferably 40 mass % or more, contains a non-equilibrium phase having a heat capacity by differential scanning calorimetry of 1 J/g or more. Furthermore, 5% or more, preferably 50% or more in terms of vol % is an amorphous phase. The alloy layer may contain, by mass %, Mg: 1 to 60% and Al: 0.07 to 59%, may further contain one or more elements selected from Cr, Mn, Fe, Co, Ni, and Cu in a total of 0.1 to 10%, and may in addition contain one or more elements of 0.

Abstract: A high strength galvanized steel sheet has a TS of 590 MPa or more and excellent processability. The component composition contains, by mass %, C: 0.05% to 0.3%, Si: 0.7% to 2.7%, Mn: 0.5% to 2.8%, P: 0.1% or lower, S: 0.01% or lower, Al: 0.1% or lower, and N: 0.008% or lower, and the balance: Fe or inevitable impurities. The microstructure contains, in terms of area ratio, ferrite phases: 30% to 90%, bainite phases: 3% to 30%, and martensite phases: 5% to 40%, in which, among the martensite phases, martensite phases having an aspect ratio of 3 or more are present in a proportion of 30% or more.

Abstract: A high strength steel sheet including, by mass, C: 0.03% or more and 0.25% or less, Si: 0.4% or more and 2.5% or less, Mn: 3.5% or more and 10.0% or less, P: 0.1% or less, S: 0.01% or less, Al: 0.01% or more and 2.5% or less, N: 0.008% or less, Si+Al: 1.0% or more, the balance being Fe and inevitable impurities. The area ratio of ferrite is 30% or more and 80% or less, the area ratio of martensite is 0% or more and 17% or less, the volume fraction of retained austenite is 8% or more, and the average grain size of retained austenite is 2 ?m or less.

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: Provided are: a high-strength steel sheet which is improved in both elongation and local formability and thus exhibits excellent workability; and a manufacturing method thereof. The high-strength steel sheet contains C, Si, Mn, Al, P and S with the remainder including iron and unavoidable impurities, and has a metal structure which includes polygonal ferrite, bainite, tempered martensite, and retained austenite. In the metal structure, (1) the bainite has a composite microstructure including both a high-temperature-formed bainite having an average distance between adjacent regions of retained austenite and/or carbide of 1 ?m or more and a low-temperature-formed bainite having an average distance between adjacent regions of retained austenite and/or carbide of less than 1 ?m each identified upon observation with a scanning electron microscope; and (2) the retained austenite is present in a volume percentage of 5% or more of the entire metal structure as determined by a saturation magnetization measurement.

Abstract: This high-strength cold-rolled steel sheet having excellent uniform elongation and hole expandability contains, C: 0.01 to 0.4%; Si: 0.001 to 2.5%; Mn: 0.001 to 4.0%; P: 0.001 to 0.15%; S: 0.0005 to 0.03%; Al: 0.001 to 2.0%; N: 0.0005 to 0.01%; and O: 0.0005 to 0.01%; in which Si+Al is limited to less than 1.0%, and a balance being composed of iron and inevitable impurities, in which at a sheet thickness center portion, an average value of pole densities of the {100}<011> to {223}<110> orientation group is 5.0 or less, and a pole density of the {332}<113> crystal orientation is 4.0 or less, a metal structure contains 5 to 80% of ferrite, 5 to 80% of bainite, and 1% or less of martensite in terms of an area ratio and the total of martensite, pearlite, and retained austenite is 5% or less, and an r value (rC) in a direction perpendicular to a rolling direction is 0.70 or more and an r value (r30) in a direction 30° from the rolling direction is 1.10 or less.

Abstract: A high tensile strength hot-dip galvannealed steel sheet having excellent coated-layer adhesiveness in which the hot-dip galvannealed layer does not peel off from a base steel sheet even in being subjected to working accompanied by sliding and a method for producing the same are provided. In the high tensile strength hot-dip galvannealed steel sheet, a hot-dip galvannealed layer is formed on the surface of the base steel sheet, the base steel sheet contains Si by 0.04-2.5%, and, when the surface roughness of the base steel sheet after the hot-dip galvannealed layer is removed by dissolution with an acid is measured for a plurality of locations by a laser microscope, the arithmetic mean inclination angle (R?a) is 23.0° or more and the root mean square inclination angle (R?q) is 29.0° or more in 60% or more of all of the locations measured.

Abstract: This high-strength cold-rolled steel sheet contains, in mass %, C: 0.02% to 0.20%; Si: 0.001% to 2.5%; Mn: 0.01% to 4.0%; P: 0.001% to 0.15%; S: 0.0005% to 0.03%; Al: 0.001% to 2.0%; N: 0.0005% to 0.01%; and O: 0.0005% to 0.01%; in which Si+Al is limited to less than 1.0%, and a balance being composed of iron and inevitable impurities, in which an area ratio of bainite in a metal structure is 95% or more, at a sheet thickness center portion being a range of ? to ? in sheet thickness from the surface of the steel sheet, an average value of pole densities of the {100}<011> to {223}<110> orientation group is 4.0 or less, and a pole density of the {332}<113> crystal orientation is 5.0 or less, and a mean volume diameter of crystal grains in the metal structure is 7 ?m or less.

Abstract: An alloy with a high glass forming ability characterized by containing a group of elements A with atomic radii of less than 0.145 nm of a total of 20 to 85 atm %, a group of elements B with atomic radii of 0.145 nm to less than 0.17 nm of a total of 10 to 79.7 atm %, and a group of elements C with atomic radii of 0.17 nm or more of a total of 0.3 to 15 atm %; when the elements with the greatest contents in the group of elements A, group of elements B, and group of elements C are respectively designated as the “element a”, “element b”, and “element c”, by the ratio of the content of the element a in the group of elements A (for example, Zn and/or Al), the ratio of the content of the element b in the group of elements B (for example, Mg), and the ratio of the content of the element c in the group of elements C (for example, Ca) all being 70 atm % or more; and by the liquid forming enthalpy between any two elements selected from the element a, element b, and element c being negative.

Abstract: The high strength galvanized steel sheet contains C: more than 0.015% and lower than 0.100%, Si: 0.3% or lower, Mn: lower than 1.90%, P: 0.015% or more and 0.05% or lower, S: 0.03% or lower, sol.Al: 0.01% or more and 0.5% or lower, N: 0.005% or lower, Cr: lower than 0.30%, B: 0.0003% or more and 0.005% or lower, and Ti: lower than 0.014% in terms of mass %, and satisfies 2.2?[Mneq]?3.1 and 0.42?8[% P]+150B*?0.73. The steel microstructure contains ferrite and a second phase, in which the second phase area ratio is 3 to 15%, the ratio of the area ratio of martensite and retained ? to the second phase area ratio is more than 70%, and 50% or more of the area ratio of the second phase exists in the grain boundary triple point.

Abstract: A surface-treated steel sheet includes: a steel sheet; and a coated layer which is formed on one surface or both surfaces of the steel sheet and includes zinc and vanadium, wherein the coated layer has a vanadium content of 1% or higher and 20% or less and a coating weight of 3 g/m2 or higher and 40 g/m2 or less, and has a plurality of dendritic arms that are grown in a thickness direction of the steel sheet, and a ratio x/y of a content x of vanadium that is present outside the arms to a content y of vanadium that is present inside the arms is 1.1 or higher and 3.0 or less in terms of vanadium element.

Abstract: The present invention relates to the field of phosphating for corrosion-protective pretreatment of zinc surfaces, being directed toward the use of largely nickel- and cobalt-free zinc phosphating solutions. The present invention makes available an alternative to trication zinc phosphating, in which the zinc surfaces of a component are firstly, before zinc phosphating, passivated with an alkaline composition containing iron(III) ions, and thereby preconditioned for a largely nickel- and cobalt-free zinc phosphating operation. In a further aspect, the invention relates to a component, in particular an automobile body, that comprises at least in part surfaces made of zinc, the zinc surfaces being covered by a two-layer system made up of a first, inner passive layer containing iron and resting on the zinc surface, and a second, outer crystalline zinc phosphate layer resting on the inner layer.

Abstract: Provided is a hot dipped galvanized steel sheet with excellent deep drawing properties and ultra-low temperature adhesive brittleness, wherein the average diameter of crystal particles of a hot-dip galvanizing layer is 150-400 ?m, and the degree of the preferred orientation with respect to the (0001) face of the hot-dip galvanizing layer is 3,000-20,000 cps (counter per second), and a preparation method thereof.

Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2.ZnSO4.xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2.ZnSO4.3-5H2O.

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: [Problem] To provide a steel sheet hot-dip-plated with a Zn—Al—Mg-based alloy coating, which is remarkably improved in point of all the burring workability, the liquid metal embrittlement cracking resistance and the corrosion resistance in the welded part thereof, as a steel material favorable for arc-welded structural members.

Abstract: A copper-based material includes a base comprising copper and a surface treatment layer disposed on a surface of the base, the surface treatment layer including an amorphous layer containing a metal element that has a greater affinity for oxygen than for copper, oxygen, and, optionally, copper diffused from the base.

Abstract: Hot dip galvanized steel sheet excellent in shapeability and plateability comprised of high strength steel sheet according to the present invention can be provided containing, by mass % about, C: 0.05 to 0.25%, Si: 0.3 to 2.5%, Mn: 1.5 to 2.8%, P: 0.03% or less, S: 0.02% or less, Al: 0.005 to 0.5%, N: 0.0060% or less and the balance of Fe and unavoidable impurities. The exemplary steel sheet can have thereon a galvanized layer containing, e.g., about Al: 0.05 to 10 mass % and Fe: 0.05 to 3 mass % and the balance of Zn and unavoidable impurities. Such exemplary hot dip galvanized steel sheet can have oxides containing Si in an average content of about 0.6 to 10 mass % at the crystal grain boundaries and in the crystal grains at the sheet steel side 5 ?m or less from the interface between the high strength steel sheet and the plating layer and by the presence of Fe—Zn alloy with an average grain size of about 0.5 to 3 ?m at the plating side.

Abstract: A hot rolled steel strip made by the steps including assembling a twin roll caster, forming a casting pool of molten steel having a free oxygen content between 20 and 75 ppm and having a composition such that the cast strip comprises by weight, greater than 0.1 and not more than 0.5% carbon, between 0.9 and 2.0% manganese, between 0.05 and 0.50% silicon, greater than 0.01% and less than or equal to 0.15% phosphorus, and less than 0.01% aluminum, counter rotating the casting rolls forming the steel strip, hot rolling the strip such that mechanical properties at 10% and 35% reduction are within 10% for yield strength, tensile strength and total elongation, and coiling the strip at a temperature between 300 and 700° C. to provide a majority of the microstructure comprising bainite and acicular ferrite. Alternatively, the steel may have between 0.20 and 0.60% copper and manganese as low as 0.08%.

Abstract: Provided is an austenitic, lightweight, high-strength steel sheet having a high yield ratio and ductility and a method for producing the same, and more particularly, to a high-strength steel sheet for automotive interior panels, exterior panels, and structural parts, and a method for producing the steel sheet. The steel sheet may be a hot-rolled steel sheet, a cold-rolled steel sheet, or a plated steel sheet. The steel sheet includes, by weight %, C: 0.6% to 1.0%, Si: 0.1% to 2.5%, Mn: 10% to 15%, P: 0.02% or less, S: 0.015% or less, Al: 5% to 8%, Ti: 0.01% to 0.20%, N: 0.02% or less, and the balance of Fe and inevitable impurities, wherein the steel sheet has a specific gravity of 7.4 g/cm3 and a Mn/Al ratio of 2 to 3.

Abstract: There is provided a hot-dip Al—Zn coated steel sheet that has a steel sheet containing Si and Mn as a base steel sheet and has excellent coating appearance and corrosion resistance. The Al—Zn coating layer has an Al content in the range of 20% to 95% by mass. The Al—Zn coating layer has a Ca content in the range of 0.01% to 10% by mass. Alternatively, the Ca and Mg content is in the range of 0.01% to 10% by mass. A steel sheet surface layer within 100 ?m from a surface of the base steel sheet directly under the Al—Zn coating layer contains 0.06 to 1.0 g/m2 per surface of an oxide of at least one selected from Fe, Si, Mn, Al, P, B, Nb, Ti, Cr, Mo, Cu, and Ni in total.

Abstract: Provided is a steel sheet for a formed member having enhanced ductility, a formed member, and a method for manufacturing the formed member, and more particularly, to a steel sheet for making a formed member having high strength and ductility such as an automotive structural member and a reinforcing member, a formed member, and a method for manufacturing the formed member. The steel sheet for a formed member has enhanced ductility, and includes, by weight %, C: 0.1% to 1.0%, Si+Al: 0.4% to 3.0%, Mn: 0.1% to 5.0%, P: 0.0001% to 0.1%, S: 0.0001% to 0.03%, N: 0.03% or less (but not 0%), and the balance of Fe and inevitable impurities. The formed member having high strength and ductility that can be used for forming an automotive structural member, a reinforcing member, etc. In addition, the formed member can be used for a heat-treatable impact resistant member.

Abstract: A high strength galvanized steel sheet is provided comprising steel containing C: 0.06% or more and 0.20% or less, Si: less than 0.50%, Mn: 0.5% or more and less than 2.0%, P: 0.05% or less, S: 0.02% or less, Al: 0.60% or more and 2.00% or less, N: less than 0.004%, Cr: 0.10% or more and 0.40% or less and B: 0.003% or less, satisfying the relationships 0.8?Mneq?2.0 and Mneq+1.3[% Al]?2.8, and a microstructure containing a ferrite phase and a second phase whose volume fraction is 15% or less, the second phase having a martensite phase whose volume fraction is 3% or more, a retained austenite phase whose volume fraction is 3% or more and a sum of the volume fractions of a pearlite phase and a bainite phase being equal to or less than the volume fraction of the martensite phase and the volume fraction of the retained austenite phase.

Abstract: There is provided a method and apparatus for plating high strength steel such as advanced high strength steel (AHSS) after irradiating the high strength steel with at least one of laser light and plasma to remove Si/Mn/Al oxides from the surface of the high strength steel, modify the surface of the high strength steel, or make the surface of the high strength steel suitable for a post process such as a zinc plating process. For this, a plating method includes heating high strength steel; treating a surface of the high strength steel with plasma to remove at least one of a Mn oxide, an Al oxide, and an Si oxide formed on the surface of the high strength steel during the heating of the high strength steel; and plating the surface-treated high strength steel.

Abstract: An Mg-based alloy plated steel material superior in adhesion and corrosion resistance characterized by being provided with a hot dip Mg-based alloy plating layer (preferably containing Zn: 15 atm % to less than 45 atm %).

Abstract: A steel sheet according to the present invention has tensile strength of 980 MPa or more, exerts a high-yield ratio, and has excellent workability (in detail, strength-ductility balance). The steel sheet contains: C: 0.06-0.12% (excluding 0.12%); Si: 0.2% or less; Mn: 2.0-3.5%; at least one element selected from the group consisting of Ti, Nb, and V of 0.01-0.15% in total; B: 0.0003-0.005%; P: 0.05% or less; S: 0.05% or less; Al: 0.005-0.1%; N: 0.015% or less; and the balance is iron and unavoidable impurities, in which the content of ferrite is more than 5% to 15% or less, that of martensite is 25-55%, and the total content of bainite and tempered martensite is 30% or more to less than 70%, based on the whole microstructure, and in which the average crystal grain size of the ferrite is 3.0 ?m or less.

Abstract: 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 0.5<Si+Al<1.0, and a metallographic structure of the steel sheet satisfies a relationship of {(n2)2/3×d2}/{(n1)2/3×d1}×ln(H2/H1)<0.3 when the n1 is the number of a MnS of a surface portion of the steel sheet, the d1 ?m is an average equivalent circle diameter of the MnS in the surface portion of the steel sheet, the H1 GPa is a hardness of a martensite of the surface portion of the steel sheet, the n2 is the number of the MnS of a center portion of the steel sheet, the d2 ?m is an average equivalent circle diameter of the MnS in the center portion of the steel sheet, and the H2 GPa is the hardness of the martensite of the center portion of the steel sheet.

Abstract: A steel sheet for hot pressing that is capable of suppressing formation of scales or ZnO in hot pressing and excellent in oxidation resistance, and a method for manufacturing a hot-pressed member using the steel sheet are provided. The steel sheet for hot pressing includes a base steel sheet and a plating layer that is formed on a surface of the base steel sheet at a coating weight of 10 to 90 g/m2 and contains 10 to 25% by mass of Ni and the balance Zn with inevitable impurities.

Abstract: A high strength galvanized steel sheet having excellent formability, includes a steel sheet which is a base sheet and a galvanized layer on a surface of the steel sheet, wherein the steel sheet is a high strength steel sheet which has a composition including, by mass %, 0.08 to 0.15% of C, 0.5 to 1.5% of Si, 0.5 to 1.5% of Mn, 0.1% or less of P, 0.01% or less of S, 0.01 to 0.1% of Al, 0.005% or less of N, and the balance Fe with inevitable impurities, and a microstructure composed of 75 to 90% of a ferrite phase as a main phase and 10 to 25% of a second phase including at least pearlite in terms of an area fraction with respect to the entire microstructure; an average grain size of the pearlite is 5 ?m or smaller; and the pearlite has an area fraction of 70% or greater with respect to the total area of the second phase.

Abstract: For obtaining a hot dip galvannealed steel sheet having high strength and high ductility and excellent phosphatability, a chemical composition of a material steel sheet for forming the hot dip galvannealed steel sheet comprises 0.4 to 2.0 mass % of Si and 1.0 to 3.5 mass % of Mn, and an average Mn concentration for a region from the uppermost surface to 0.01 ?m depth in the coating layer is defined as 0.14% or more.

Abstract: A vibration-damping composite material includes a clad material that includes a base material includes a zinc-aluminum alloy and metal layers each including a ferritic stainless steel on both surfaces of the base material. A total thickness of the metal layers is not less than 40% and not more than 80% of the thickness of the clad material.

Abstract: It is an object of the present invention to provide a high strength cold-rolled steel sheet, which has superior bake hardenability, aging resistance at room temperature and secondary work embrittlement resistance, and a method for manufacturing the same. The steel sheet has a grain size of ASTM No. of 9 or more after annealing, a BH of 30 MPa or more, an AI of 30 MPa or less, and a tensile strength of 340˜390 MPa through appropriate control of solute elements in steel by addition of a small amount of Ti, addition of Al and Mo, and control of manufacturing conditions, and refinement of crystal grains after annealing. The cold-rolled steel sheet and the galvannealed steel sheet produced using the cold-rolled steel sheet have the superior bake hardenability, aging resistance at room temperature, and secondary work embrittlement resistance.

Abstract: A steel material which is suitable for hot press working or hot three-dimensional bending and direct quench and which can be used to manufacture a high-strength formed article with sufficient quench hardening even by short time heating at a low temperature has a chemical composition comprising, in mass percent, C: 0.05-0.35%, Si: at most 0.5%, Mn: 0.5-2.5%, P: at most 0.03%, S: at most 0.01%, sol. Al: at most 0.1%, N: at most 0.01%, and optionally at least one element selected from the group consisting of B: 0.0001-0.005%, Ti: 0.01-0.1%, Cr: 0.18-0.5%, Nb: 0.03-0.1%, Ni: 0.18-1.0%, and Mo: 0.03-0.5% and has a steel structure in which the spheroidization ratio of carbides is 0.60-0.90.

Abstract: Hot-rolled or cold-rolled steel plate, method for manufacturing same and use thereof in the automotive industry A hot-rolled or cold-rolled steel plate, characterized in that its composition is in weight percentages: 0.6%?C?0.9%; 17%?Mn?22%; 0.2%?Al?0.9%; 0.2%?Si?1.1% with 0.85%?Al+Si?1.9%; 1.2%?Cu?1.9%; S?0.030%; P?0.080%; N?0.1%; optionally: Nb?0.25% and preferably comprised between 0.070 and 0.25%; V?0.5% and preferably comprised between 0.050 and 0.5%; Ti?0.5%, and preferably comprised between 0.040 and 0.5%; Ni?2%; trace amounts Cr?2%, preferably?1%; B?0.010%, and preferably, comprised between 0.0005% and 0.010%; the remainder being iron and impurities resulting from the production. A method for manufacturing this plate, the use of this plate in the automotive industry.

Abstract: High-strength, cold-formable steel and a flat steel product produced from such a steel, in which an optimal combination of weldability and a low tendency towards delayed cracking is ensured along with good strength and hot and cold deformability. In order to achieve this, a steel according to the invention contains (in % by weight) C: 0.1-1.0%, Mn: 10-25%, Si: up to 0.5%, Al: 0.3-2%, Cr: 1.5-3.5%, S: <0.03%, P: <0.08%, N: <0.1%, Mo: <2%, B: <0.01%, Ni: <8%, Cu: <5%, Ca: up to 0.015%, at least one element from the group “V, Nb” with the following proviso: Nb: 0.01-0.5%, V: 0.01-0.5% and optionally Ti: 0.01-0.5% and iron and unavoidable, production-related impurities as the remainder.

Abstract: Provided is a metal coated steel sheet having a coating layer including a metal having a level of Gibbs free energy equal to that of Fe or above and an oxide thereof. Accordingly, the quality of a plated steel sheet may be improved by preventing the generation of bare spots through inhibition of the formation of Mn oxide, Si oxide, or Al oxide on the surface thereof, and simultaneously, the complexity of a manufacturing facility or an increase in manufacturing costs may be minimized. Economic benefits are thus realized.

Abstract: Provided are a pipe which exhibits corrosion resistance against vapor of fuel such as gasoline, diesel oil, bioethanol or a biodiesel fuel, a method for manufacturing the pipe, and a steel sheet for manufacturing the pipe. A method for manufacturing a pipe having a bent portion which has excellent corrosion resistance against fuel vapor includes the steps of; preparing a steel sheet for manufacturing a pipe which is characterized by having a zinc-nickel (Zn—Ni) alloy layer where a nickel content is 4 to 16 at % on at least one surface of the steel sheet; forming the steel sheet for manufacturing a pipe into a tubular shape such that the Zn—Ni alloy layer forms an inner surface of the pipe, and applying bending to the pipe such that the elongation of the bent convex portion generated at the time of bending the pipe falls within 20%.

Abstract: A hot rolled steel strip made by the steps including assembling a twin roll caster, forming a casting pool of molten steel of such composition that the cast strip produced comprises by weight, greater than 0.25% and up to 1.1% carbon, between 0.40 and 2.0% manganese, between 0.05 and 0.50% silicon, less than 0.01% aluminum, counter rotating the casting rolls to solidify metal shells and forming a steel strip, hot rolling the steel strip such that mechanical properties at 10% and 35% reduction are within 10% for yield strength, tensile strength and total elongation, and coiling the hot rolled steel strip at a temperature between 550 and 750° C. to provide a majority of the microstructure comprising pearlite, along with bainite and acicular ferrite. The steel may have a free oxygen content between 5 and 50 ppm or between 25 and 45 ppm.

Abstract: Provided is a hot dip zinc (Zn) alloy plated steel sheet having excellent corrosion resistance and surface qualities, and a method of manufacturing the same. For this purpose, the present invention provides a high corrosion resistant hot dip Zn alloy plated steel sheet which includes an underlying steel sheet and a hot dip Zn alloy plating layer, wherein a composition of the hot dip Zn alloy plating layer includes 1 to 3 wt % of aluminum (Al), 1.5 to 4.0 wt % of magnesium (Mg), and Zn and avoidable impurities as a remainder, in which Al+Mg is in a range of 2.5 to 7.0 wt % and Al:(Al+Mg) is in a range of 0.38 to 0.48, and a method of manufacturing the high corrosion resistant hot dip Zn alloy plated steel sheet.