Provided is a rolling die that increases the durability of a nitrided molded surface. The rolling die (1) includes a tool base material that is made of steel and has a molded surface (2) on which a plurality of working teeth (10) is formed. The tool base material includes a nitride layer (15) in which nitrogen is diffused. The nitride layer (15) is disposed to reach a position that is 20 to 70 μm in depth from the molded surface (2). The molded surface (2) has a surface hardness of at least 1100 HV. The rate of depth change from the depth (D1) of the nitride layer (15) at crests (11) of the working teeth (10) to the depth (D2) of the nitride layer (15) at roots (13) of the working teeth (10) is not higher than 30%.

Provided is a rolling die that increases the durability of a nitrided molded surface. The rolling die (1) includes a tool base material that is made of steel and has a molded surface (2) on which a plurality of working teeth (10) is formed. The tool base material includes a nitride layer (15) in which nitrogen is diffused. The nitride layer (15) is disposed to reach a position that is 20 to 70 μm in depth from the molded surface (2). The molded surface (2) has a surface hardness of at least 1100 HV. The rate of depth change from the depth (D1) of the nitride layer (15) at crests (11) of the working teeth (10) to the depth (D2) of the nitride layer (15) at roots (13) of the working teeth (10) is not higher than 30%.

The invention relates to an apparatus (1) for producing a peripheral groove (101) in an end portion (103) of a metal tube (100), in particular a metal tube (100) which is to be coated on the inside, the groove (101) being set up for receiving tube connectors, having a first, rotationally driven roller (3), a second, freely rotating roller (5), the first roller (3) having a roughened or structured surface (6) relative to the second roller (5), a pressing device (15) for producing a relative movement between the first and second roller (3, 5), between a first and a second position, the rollers (3, 5) assuming a first spacing from one another in the first position, which first spacing permits an introduction of a wall of the tube between the rollers (3, 5), and assuming a smaller, second spacing from one another in the second position, which second spacing is smaller than a material thickness (M) of the wall of the tube.

It is proposed according to the invention that the first, driven roller (3) is set up to grip the tube from the outside in the second position and to rotate it, with the result that a peripheral groove (101) is pressed into the tube in the second position when the first roller (3) is driven.

A working roller for a rolling mill for laminating a sheet of alkali metal or alloy thereof into a film is disclosed. The working roller has a cylindrical center portion defining a central axis, the center portion having an outer surface defining a lamination surface; and first and second frustoconical portions extending from first and second ends of the center portion respectively. When the central axis is straight, an angle between the outer surface of the center portion and an outer surface of each of the first and second frustoconical portions is less than 0.05 degrees. A width of the center portion is greater than a width of each of the first and second frustoconical portions. The width of the center portion is less than a sum of the widths of the first and second portions. A rolling mill having two such working rollers is also disclosed.

Provided is a hot-dip galvanized steel sheet to be used for home appliances, vehicles, and the like, and having excellent surface appearance and low-temperature bonding brittleness. The hot-dip galvanized steel sheet includes: a base steel sheet; and a hot-dip galvanized layer formed on the base steel sheet. A surface of the base steel sheet has a centerline average roughness (Ra) of 0.3 or more, a roughness skewness (Rsk) of −1 or less, and a roughness kurtosis (Rku) of 6 or more.

A rolling device (1), a method and a rolling train (35) for the cold rolling of rolled stock (3). The rolling device (1)-a rolling stand (5), multiple assembly sets for optionally assembling the rolling stand (5) with one of the assembly sets, and a working-roll drive. Each assembly set comprises two working rolls (7, 8), and for each working roll (7, 8) two working-roll chocks (9). A spindle head (11), can be connected to a working roll journal (16) of the working roll (7, 8). The working rolls (7, 8) of different assembly sets have different working-roll diameter ranges, which are determined by a respective minimum working-roll diameter and maximum working-roll diameter. The rolling stand (5) has mountings (19) for a respective working-roll chock (9) of an assembly set. The working-roll drive has two drive spindles (27), each for driving a working roll (7, 8) via the spindle head (11) assigned to the working roll (7, 8) by rotations about a longitudinal axis of the drive spindle (27).

A method for preparing an ultrafine-grained superalloy bar, the method including: 1) designing a rolling machine including two rollers and two guide plates, where each of the two rollers includes a first roller and a second roller; the first roller includes a first curve and the second roller includes a second curve; the first curve and the second curve form a generatrix of the two rollers; 2) disposing the two guide plates with two curved surfaces thereof opposite to each other; disposing the two rollers to be between the two guide plates; where the two rollers and the two guide plates form a deformation zone of the rolling machine; and 3) driving the two rollers to rotate around their central axes, heating and introducing a superalloy blank from a gap between two first rollers to the deformation zone of the rolling machine; advancing the superalloy blank towards two second rollers.

A vertical Pittsburgh Seam closing apparatus having a base supporting surface, a track mechanism for moving a carriage assembly which holds seam forming members used to close a Pittsburgh Seam, a pair of upper and lower guide members for guiding the duct section into a proper vertical position, and upper and lower clamping members positioned inside the duct section and adjacent the inside portion of the Pittsburgh Seam to be closed, the upper guide members and clamping member being selectively movable and adjustable for accommodating different duct section lengths. In one embodiment, the seam forming assembly includes three roller members mounted in vertical arrangement to each other, one roller member being V-shaped in configuration and the other two roller members being substantially cylindrical in shape. The V-shaped roller member may also include one or more projecting members for forming dimples in the closing process to prevent shifting and/or slipping of the closed seam.

A vertical Pittsburgh Seam closing apparatus having a base supporting surface, a track mechanism for moving a carriage assembly which holds seam forming members used to close a Pittsburgh Seam, a pair of upper and lower guide members for guiding the duct section into a proper vertical position, and upper and lower clamping members positioned inside the duct section and adjacent the inside portion of the Pittsburgh Seam to be closed, the upper guide members and clamping member being selectively movable and adjustable for accommodating different duct section lengths. In one embodiment, the seam forming assembly includes three roller members mounted in vertical arrangement to each other, one roller member being V-shaped in configuration and the other two roller members being substantially cylindrical in shape. The V-shaped roller member may also include one or more projecting members for forming dimples in the closing process to prevent shifting and/or slipping of the closed seam.

A centrifugally cast composite roll for rolling comprising an outer layer and an inner layer, which are integrally fused to each other, the outer layer being made of an Fe-based alloy comprising by mass 1.70-2.70% of C, 0.3-3% of Si, 0.1-3% of Mn, 1.1-3.0% of Ni, 4.0-10% of Cr, 2.0-7.5% of Mo, 3-6.0% of V, 0.1-2% of W, 0.2-2% of Nb, 0.01-0.2% of B, and 0.01-0.1% of N, the balance being Fe and inevitable impurities, and the inner layer being made of ductile cast iron.