Flatness of a hot-rolled steel sheet in a coil is improved when the hot-rolled steel sheet is wound with a mandrel in a hot-rolling process to manufacture a coil. The mandrel has a protruding shape with a center portion in an axial direction protruding from both end portions when seen from a lateral side in the axial direction. Regarding a peripheral length difference, which is a difference between a peripheral length of the center portion of the mandrel and a peripheral length at a predetermined distance from the center portion, the ratio of the peripheral length difference to the peripheral length of the center portion is preferably 0.0002 to 0.012. The protruding shape may be a trapezoidal shape or a polynomial function shape.

An apparatus for winding up a metal strip into a coil. A frame in which a second counter-bending roller is mounted in a rotatable manner. The frame is movable with the aid of a second setting device between a coiler shaft position and a roller bed position. In the roller bed position, the second counter-bending roller alongside a first counter-bending roller acts as the roller bed roller of a roller bed which is arranged above the coiling device.

An overlapping and progressive forming method for a high-performance multi-element NiAl-based alloy tubular part, including: winding continuously flexible substrates of Ni and Al, and alloying coating continuously or selectively along a width direction or a rolling direction to obtain coated flexible substrates; winding continuously the coated flexible substrates on an outer surface of a core roller according to a sequence of Ni above and Al below to form a Ni/Al laminated structure having a plurality of layers with an outermost layer being a Ni layer, and consolidating with ultrasonic with assistance of a pulse current to combine the continuously wound flexible substrates into a laminated tube blank; and placing the laminated tube blank into a mold, applying a pulse current to both ends of the laminated tube blank for hot fluid high-pressure forming, and synthesizing in-situ to prepare the tubular part with assistance of the pulse current.

A coiling device includes a coiler (1) having a coiling mandrel (3) for coiling a metal strip (2) which is fed (x) to the coiler (1), and a coiling swing arm (4) having a front and a rear pressure roller (5, 6) and a deflection plate (7). A swing arm drive (8) lines up the coiling swing arm (4) with the coiling mandrel (3) and is driven away from the coiling mandrel (3). An upper duct flap (9) upstream of the coiler (1) in the feed direction (x) for guiding the metal strip (2). A flap drive (10) for positioning the upper duct flap (9) such that, when the coiling swing arm (4) is lined up with the coiling mandrel (3), the upper duct flap is arranged between the coiling mandrel (3) and the front pressure roller (5) of the coiling swing arm (4) or is arranged upstream of the front pressure roller (5) of the coiling swing arm (4). In the first-mentioned case, the metal strip (2) is deflected around the coiling mandrel (3) only by the rear pressure roller (6) and the deflection plate (7) of the coiling swing arm (4) and, in the last-mentioned case, additionally also by the front pressure roller (5).

Flatness of a hot-rolled steel sheet in a coil is improved when the hot-rolled steel sheet is wound with a mandrel in a hot-rolling process to manufacture a coil. The mandrel has a protruding shape with a center portion in an axial direction protruding from both end portions when seen from a lateral side in the axial direction. Regarding a peripheral length difference, which is a difference between a peripheral length of the center portion of the mandrel and a peripheral length at a predetermined distance from the center portion, the ratio of the peripheral length difference to the peripheral length of the center portion is preferably 0.0002 to 0.012. The protruding shape may be a trapezoidal shape or a polynomial function shape.

An apparatus for winding up a metal strip into a coil. A frame in which a second counter-bending roller is mounted in a rotatable manner. The frame is movable with the aid of a second setting device between a coiler shaft position and a roller bed position. In the roller bed position, the second counter-bending roller alongside a first counter-bending roller acts as the roller bed roller of a roller bed which is arranged above the coiling device.

A coiling device that includes a coiler (1) having a coiling mandrel (3) for coiling a metal strip, and a coiling swing arm (4) having front and a rear pressure rollers (5, 6) and a deflection plate (7). A swing arm drive (8) lines up the coiling swing arm (4) with the coiling mandrel (3) and is driven away from the coiling mandrel (3). An upper duct flap (9) upstream of the coiler (1) in the feed direction (x) guides the metal strip (2). A flap drive (10) positions the upper duct flap (9) such that, when the coiling swing arm (4) is lined up with the coiling mandrel (3), the upper duct flap is arranged between the coiling mandrel (3) and the front pressure roller (5) of the coiling swing arm (4) or is arranged upstream of the front pressure roller (5) of the coiling swing arm (4).

In rolls of winding equipment in a hot-rolling factory, each roll includes a lower cladding layer formed on the surface of the roll barrel and a self-fluxing alloy layer formed on the lower cladding layer by thermal spraying and containing carbide particles dispersed therein. The lower cladding layer includes an Fe-based cladding layer which has a Shore hardness of 60 or greater and which contains, in terms of mass %, 0.1-0.4 C, up to 2.0 Si, up to 3.0 Mn, 1.0-15.0 Cr, and 2.5-5.0 Ni. The lower cladding layer further contains one or more of Mo, V, and Co, the contents of Mo, V, and Co being 0.1-5.0 mass %, 0.1-3.0 mass %, and 0.5-5.0 mass %, respectively.

A winding device suitable for winding at least one strip on a mandrel. According to one embodiment the winding device includes a pressure assembly configured to press a strip against the surface of the mandrel when winding the strip. The pressure assembly comprises a first pressure unit which is coupled to and rotates together with the mandrel from a first winding position to a second winding position while the first pressure unit presses on the strip. The pressure assembly further comprises a second pressure unit that is attached to the first pressure unit, and that is configured for pressing on the strip when the first pressure unit reaches the second winding position, allowing forward movement of the strip in the winding direction when the mandrel rotates.

An overlapping and progressive forming method for a high-performance multi-element NiAl-based alloy tubular part, including: winding continuously flexible substrates of Ni and Al, and alloying coating continuously or selectively along a width direction or a rolling direction to obtain coated flexible substrates; winding continuously the coated flexible substrates on an outer surface of a core roller according to a sequence of Ni above and Al below to form a Ni/Al laminated structure having a plurality of layers with an outermost layer being a Ni layer, and consolidating with ultrasonic with assistance of a pulse current to combine the continuously wound flexible substrates into a laminated tube blank; and placing the laminated tube blank into a mold, applying a pulse current to both ends of the laminated tube blank for hot fluid high-pressure forming, and synthesizing in-situ to prepare the tubular part with assistance of the pulse current.