A method for producing ultra-thin hot-rolled strip steel, the method comprising the following process steps: A. a smelting process: feeding scrap steel into an induction electric furnace (1) for smelting so that the scrap steel melts into molten steel; B. a refining process: using a ladle refining furnace (2) and a ladle vacuum degassing furnace (3) to refine the molten steel; C. a continuous casting process: casting the refined molten steel into a cast strip blank that has a thickness of 1.6-2.5 mm by means of a dual-roller thin strip continuous casting system (4); D. a hot rolling process: directly feeding the cast strip blank that was cast in the continuous casting process to a single-stand hot rolling mill (9) for rolling to produce hot-rolled strip steel, the thickness of the hot-rolled strip steel being 0.8-1.5 mm; E. a cooling coiling process: performing atomizing cooling on the hot-rolled strip steel, and coiling after the strip steel temperature is controlled to be 400-750° C. The present method achieves an extremely compact, environmentally-friendly and economical ultra-thin hot-rolled strip steel production process flow, and achieves the environmentally-friendly and economical continuous production of metal plates and strips.

Disclosed herein is a light-gauge, ultra-high strength weathering steel pile for use as a steel foundation in structures such as, for example, solar arrangements. The light-gauge, ultra-high strength weathering steel pile comprises a thickness of 2.5 mm or less that has been cold roll formed into a steel pile having a web and a pair of opposing flanges, each having discontinuities formed therein. The steel pile further comprises a yield strength of between 700 and 1600 MPa, a tensile strength of between 1000 and 2100 MPa, and an elongation of between 1% and 10%.

A high-strength galvanized steel sheet includes a steel sheet containing a predetermined component element, a mass ratio of a content amount of Si to a content amount of Mn in the steel (Si/Mn) being 0.2 or more, and a steel structure in which an average grain size of inclusions existing in an area extending from a surface to a position of ⅓ of a sheet thickness is 50 μm or less, and an average nearest distance between ones of the inclusions is 20 μm or more; and a galvanized layer provided on a surface of the steel sheet, in which an amount of diffusible hydrogen contained in the steel is less than 0.25 mass ppm, oxides containing predetermined elements in an outer layer portion of the steel sheet account for 0.010 g/m.sup.2 or more per one surface, and a tensile strength is 1100 MPa or more.

A method for manufacturing a thin strip component, including a processing step of processing an amorphous thin strip member into a dimension shape larger than a target shape, and a heat treating step of heat treating and contracting the amorphous thin strip member processed in the processing step to form the amorphous thin strip member into a thin strip component of the target shape. A thin strip component which is a magnetic laminate in which a plurality of plate-shaped thin strip component members of the same shape are laminated, and has a recess over an entire side surface of the magnetic laminate is used. A motor including the thin strip component, a plurality of coils disposed on the thin strip component, and a rotor disposed between the plurality of coils is used.

Disclosed herein is a light-gauge, ultra-high strength weathering steel pile for use as a steel foundation in structures such as, for example, solar arrangements. The light-gauge, ultra-high strength weathering steel pile comprises a thickness of 2.5 mm or less that has been cold roll formed into a steel pile having a web and a pair of opposing flanges, each having discontinuities formed therein. The steel pile further comprises a yield strength of between 700 and 1600 MPa, a tensile strength of between 1000 and 2100 MPa, and an elongation of between 1% and 10%.

Disclosed herein is a light-gauge, ultra-high strength weathering steel sheet with a composition, material properties, and surface characteristics that make it suitable for hot-stamping applications and making hot-stamped products. Also disclosed herein is a high friction rolled carbon alloy steel strip free of prior austenite grain boundary depressions and having a smear pattern. Still further disclosed herein is a high friction rolled carbon alloy steel strip that has been surface homogenized to provide a thin cast steel strip free of a smear pattern.

A method for manufacturing a thin strip component, including a processing step of processing an amorphous thin strip member into a dimension shape larger than a target shape, and a heat treating step of heat treating and contracting the amorphous thin strip member processed in the processing step to form the amorphous thin strip member into a thin strip component of the target shape. A thin strip component which is a magnetic laminate in which a plurality of plate-shaped thin strip component members of the same shape are laminated, and has a recess over an entire side surface of the magnetic laminate is used. A motor including the thin strip component, a plurality of coils disposed on the thin strip component, and a rotor disposed between the plurality of coils is used.

A cold-rolled and heat-treated steel sheet having a microstructure of, in surface fraction: between 10% and 30% of retained austenite, said retained austenite being present as films having an aspect ratio of at least 3 and as Martensite Austenite islands, less than 8% of such Martensite Austenite islands having a size above 0.5 m, at most 10% of fresh martensite and recovered martensite containing precipitates of at least one element chosen among niobium, titanium and vanadium. A manufacturing method thereof is also provided.

A coated steel substrate including a coating comprising nanographite having a lateral size between 1 and 60 m and a binder, wherein the steel substrate has the following compositions in weight percent: 0.31C1.2%, 0.1Si1.7%, 0.15Mn1.1%, P0.01%, S0.1%, Cr1.0%, Ni1.0%, Mo0.1%, and on a purely optional basis, one or more elements such as Nb0.05%, B0.003%, Ti0.06%, Cu0.1%, Co0.1%, N0.01%, V0.05%, the remainder of the composition being made of iron and inevitable impurities resulting from the elaboration and a method for the manufacture of the coated steel substrate.

Provided is a precipitation-hardening hot rolled steel sheet, having excellent material uniformity and hole expandability, comprising, by weight, 0.02% to 0.05% of C, 0.01% to 0.3% of Si, 1.0% to 1.6% of Mn, 0.04% to 0.1% of Ti, 0.01% to 0.05% of Nb, 0.008% or less of N, and a remainder of Fe and inevitable impurities, satisfying Relationship 1, wherein a microstructure of the precipitation-hardening hot rolled steel sheet comprises 95 area % or more of ferrite and (Ti, Nb)C complex precipitates, the number of (Ti, Nb)C complex precipitates having a diameter of 10 nm or less is five or more times the number of (Ti, Nb)C complex precipitates having a diameter greater than 10 nm. Relationship 1: 0.35(Ti+Nb+V+Mo)/(C+N) 0.70.