A method disclosed herewith is a method for producing a first seamless metal tube with a first wall thickness and a second seamless metal tube with a second wall thickness by using a three-roll-type inclined rolling mill, and the method includes a first inclination rolling step (#5), a setting changing step (#10), and a second inclination rolling step (#15). At the first inclination rolling step, a first workpiece is rolled by the inclined rolling mill. At the setting changing step, a setup condition of the inclined rolling mill is changed in a manner (a) or (b) as described below. At the second inclined rolling step, a second workpiece is rolled by the inclined rolling mill under the changed condition. (a) When the second wall thickness is smaller than the first wall thickness, the cross angle of each of the inclined rolls is made greater than the cross angle set for the first inclination rolling step. (b) When the second wall thickness is larger than the first wall thickness, the cross angle of each of the inclined rolls is made smaller than the cross angle set for the first inclination rolling step.

An electric resistance welded steel pipe having excellent formability and torsional fatigue resistance and a method for manufacturing the same. The electric resistance welded steel pipe includes a seam region and a base metal region, the seam region having a range of ±10 degrees in a pipe circumferential direction with respect to an electric resistance welded seam formed in a pipe longitudinal direction, the base metal region being a region other than the seam region. The electric resistance welded steel pipe has an r-value in the pipe longitudinal direction of 1.0 or greater, H (mm) and W (mm) satisfy a specified formula, and Ts.sub.(MAX) (mm) and Tb.sub.(Ave) (mm) satisfy a specified formula.

In a multi-roll table ring-rolling mill and method, a mandrel roll can be switched from a rolling state into a free-running state, when a predetermined ring diameter is reached, even if the roll gap minimum has not yet been reached, in order to improve the size accuracy of the rolled rings. A mandrel roll table rotating about a mandrel table axle is used, along with at least one main roll rotating about a main roll axle and first and second mandrel rolls that are mounted in the mandrel roll table, and a relief device to relieve at least the first mandrel roll of rolling forces. The main roll axle and the mandrel roll table axle are mounted in unchangeable manner and eccentric to one another, at least during the rolling process. The relief device acts independent of the main roll axle and the mandrel roll table axle are eccentric to one another.

A method for producing hot-rolled, seamless pipes having at least one wall thickening which can be arranged at any positions over the length of the pipe, wherein by means of a multiple-stand mandrel bar rolling mill, the rolls roll a hollow shell on a mandrel bar as an inner tool to a required nominal wall thickness and produce at specified positions over the length of the pipe a required wall thickening on the outer side of the pipe by opening the rolls in the rolling stands. The thickened wall is produced and finish-rolled by two rolling stands that are consecutive as seen in the rolling direction, in which the deviations of the finished contour of the thickening from an ideal circular cross-section are minimised, wherein the rolling stands located upstream are likewise opened as to avoid any contact of the rolls of these rolling stands with the previously produced thickening.

A calcium-bearing magnesium and rare earth element alloy consists essentially of, in mass percent, zinc (Zn): 1-3%; aluminum (Al): 1-3%; calcium (Ca): 0.1-0.4%; gadolinium (Gd): 0.1-0.4%; yttrium (Y): 0-0.4%; manganese (Mn): 0-0.2%; and balance magnesium (Mg).

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 device having at least one pair of free-running cooling rollers for the continuous production of a fibre strip impregnated with polymer, wherein the fibres are continuous fibres and the fibres in the impregnated fibre strip are aligned unidirectionally in the direction of travel of the impregnated fibre strip. Preferably, at least one of the two rollers is equipped with a pair of sealing rings preferably of the same type. Also disclosed is a polymer-impregnated fiber strip, a process for producing a polymer-impregnated fiber strip, and a multilayer composite.

Provided is a method for performing an external pipe thread process on a hollow blank by at least twice rolling: firstly, the first rolling wheel group rolls the outer surface of the hollow blank into a threaded cylindrical surface or a threaded conical surface or a threaded cylindrical conical mixing surface, and secondly, the second rolling wheel group rolls again for the outer surface of the hollow blank which has processed in step 1, and rolling to form an external pipe thread; wherein the number of rolling wheels in a rolling wheel group, used in any two back-to-back rolling processes in a processing sequence, are different in parity. Further provided are various rolling head, module, apparatuses and production line for pipe thread, achieving the above processing method and having a simple structure, portability and practicality. When preforming an external pipe thread rolling process of the hollow blank, thereby improving a processing yield; in addition, the invention also provides a threaded cylindrical surface or a threaded conical surface or threaded cylindrical conical mixing surface products by the first rolling wheel group.

A calcium-bearing magnesium and rare earth element alloy consists essentially of, in mass percent, zinc (Zn): 1-3%; aluminum (Al): 1-3%; calcium (Ca): 0.1-0.4%; gadolinium (Gd): 0.1-0.4%; yttrium (Y): 0-0.4%; manganese (Mn): 0-0.2%; and balance magnesium (Mg).

A device having at least one pair of free-running cooling rollers for the continuous production of a fibre strip impregnated with polymer, wherein the fibres are continuous fibres and the fibres in the impregnated fibre strip are aligned unidirectionally in the direction of travel of the impregnated fibre strip. Preferably, at least one of the two rollers is equipped with a pair of sealing rings preferably of the same type. Also disclosed is a polymer-impregnated fiber strip, a process for producing a polymer-impregnated fiber strip, and a multilayer composite.