Provided is an ultra-high strength steel sheet used as a material of a vehicle and, more specifically, to an ultra-high strength steel sheet having excellent bendability and a manufacturing method therefor. There is an effect of providing a steel sheet by utilizing a continuous annealing furnace without having water quenching equipment, thereby simultaneously ensuring a tensile strength of 1200 MPa or greater compared with that of conventional super high strength martensite steel and having excellent shape and bending properties.

Provided is an ultra-high strength steel sheet used as a material of a vehicle and, more specifically, to an ultra-high strength steel sheet having excellent bendability and a manufacturing method therefor. There is an effect of providing a steel sheet by utilizing a continuous annealing furnace without having water quenching equipment, thereby simultaneously ensuring a tensile strength of 1200 MPa or greater compared with that of conventional super high strength martensite steel and having excellent shape and bending properties.

A method for producing a feedstock wire is produced from a first metal strip and at least one further metal strip by roll forming, wherein in particular the first metal strip and the at least one further metal strip are made of differing metals, preferably of differing meals having differing yield points, wherein a jacket, which in the final shape completely surrounds the at least one further metal strip in the circumferential direction, is formed from the first metal strip in a plurality of passes by roll forming using a plurality of roll stands, and wherein, first, exclusively only the first metal strip is formed to a preliminary shape in a plurality of passes using a first group of roll stands and, thereafter, the first metal strip and the at least one further metal strip are jointly formed to the final shape in a second group of roll stands.

A porous amorphous silicon which enables improvement in battery performances such as charge/discharge efficiency and battery capacity when used as the anode material; a method for producing a porous amorphous silicon, capable of producing a porous amorphous silicon composed entirely of amorphous silicon at relatively low cost in a short time; and a secondary battery using the porous amorphous silicon as the anode material. A molten metal containing metal and silicon is cooled at a cooling rate of 10.sup.6 K/sec or more to form an eutectic alloy including the metal and the silicon, and then the metal is selectively eluted from the eutectic alloy with an acid or an alkali to obtain a porous amorphous silicon. The porous amorphous silicon has a lamellar or columnar structure having a mean lamellar diameter or a mean column diameter of 1 nm to 100 nm.

A porous amorphous silicon which enables improvement in battery performances such as charge/discharge efficiency and battery capacity when used as the anode material; a method for producing a porous amorphous silicon, capable of producing a porous amorphous silicon composed entirely of amorphous silicon at relatively low cost in a short time; and a secondary battery using the porous amorphous silicon as the anode material. A molten metal containing metal and silicon is cooled at a cooling rate of 10.sup.6 K/sec or more to form an eutectic alloy including the metal and the silicon, and then the metal is selectively eluted from the eutectic alloy with an acid or an alkali to obtain a porous amorphous silicon. The porous amorphous silicon has a lamellar or columnar structure having a mean lamellar diameter or a mean column diameter of 1 nm to 100 nm.

A manufacturing process of a high-strength aluminum alloy wire/strip includes the following steps: A. subjecting an alloy to smelting and spray forming to obtain a high-strength Al—Zn—Mg—Cu aluminum alloy blank; B. subjecting the blank to semi-solid upset forging to form an ingot; C. subjecting the ingot to hot extrusion and then to vacuum annealing to form a coiled material; D. subjecting the coiled material to hot continuous rolling to obtain a wire blank; and E. subjecting the wire blank to solution heat treatment, multiple stretching treatments, annealing, and multiple continuous stretching treatments to obtain the high-strength aluminum alloy wire/strip. The high-strength aluminum alloy wire/strip has the characteristics of fine and compact grains, uniform structure, clear grain boundaries, no precipitates, and no layered structure affecting the stretching performance.

An aluminum alloy having a composition including 0.1% by mass or more and 2.8% by mass or less of Fe; and 0.002% by mass or more and 2% by mass or less of Nd.

A spring steel wire includes a main body made of a steel and having a line shape, and an oxidized layer covering an outer peripheral surface of the main body. The steel constituting the main body contains not less than 0.5 mass % and not more than 0.7 mass % C, not less than 1 mass % and not more than 2.5 mass % Si, not less than 0.2 mass % and not more than 1 mass % Mn, and not less than 0.5 mass % and not more than 2 mass % Cr, with the balance being Fe and unavoidable impurities. The steel constituting the main body has a pearlite structure. The oxidized layer has a thickness of not less than 2 μm and not more than 5 μm. The oxidized layer contains not less than 60 mass % Fe.sub.3O.sub.4.

A spring steel wire includes a main body made of a steel and having a line shape, and an oxidized layer covering an outer peripheral surface of the main body. The steel constituting the main body contains not less than 0.5 mass % and not more than 0.7 mass % C, not less than 1 mass % and not more than 2.5 mass % Si, not less than 0.2 mass % and not more than 1 mass % Mn, and not less than 0.5 mass % and not more than 2 mass % Cr, with the balance being Fe and unavoidable impurities. The steel constituting the main body has a pearlite structure. The oxidized layer has a thickness of not less than 2 μm and not more than 5 μm. The oxidized layer contains not less than 60 mass % Fe.sub.3O.sub.4.

Described is a hot-rolled steel strip product including a composition consisting of, in terms of weight percentages, 0.14% to 0.35% C, 0% to 0.5% Si, 0.05% to 0.40% Mn, 0.1% or less Al, 0.1% to 0.4% Cu, 0.2% to 0.9% Ni, 0.2% to 0.9% Cr, 0.2% or less Mo, 0.005% or less Nb, 0.035% or less Ti, 0.05% or less V, 0.0005% to 0.0050% B, 0.025% or less P, 0.008% or less S, 0.01% or less N, 0.01% or less Ca, and the remainder being Fe and inevitable impurities, wherein the steel product has a Brinell hardness in the range of 420 to 580 HBW.