A method of manufacturing a rectangular tube having a stepped portion includes: forming V-shaped grooves on a rectangular tube at surfaces of an end thereof in a direction parallel to a longitudinal direction thereof; and pressing each of the surfaces having the V-shaped grooves formed thereon with a rotating roll from outside to inside, whereby the end of the rectangular tube is radially reduced.

A method of manufacturing a rectangular tube having a stepped portion includes: forming V-shaped grooves on a rectangular tube at surfaces of an end thereof in a direction parallel to a longitudinal direction thereof; and pressing each of the surfaces having the V-shaped grooves formed thereon with a rotating roll from outside to inside, whereby the end of the rectangular tube is radially reduced.

A method of manufacturing a rectangular tube having a stepped portion includes: forming V-shaped grooves on a rectangular tube at surfaces of an end thereof in a direction parallel to a longitudinal direction thereof; and pressing each of the surfaces having the V-shaped grooves formed thereon from outside to inside, whereby the end of the rectangular tube is radially reduced.

A method of manufacturing a rectangular tube having a stepped portion includes: forming V-shaped grooves on a rectangular tube at surfaces of an end thereof in a direction parallel to a longitudinal direction thereof; and pressing each of the surfaces having the V-shaped grooves formed thereon from outside to inside, whereby the end of the rectangular tube is radially reduced.

A coil made of a coiled metal strip, in particular an aluminum strip, having a marking on a flat side of the metal strip. In order to be able, inter alia, to clearly identify the strip segments severed from the coil it is proposed that the marking, for allocating strip segments severed from the coil to the coil and the original position of the marking on the coil, comprises an information track, preferably extending across the entire strip length of the metal strip having a de-Bruijn sequence of successively arranged words of said de-Bruijn sequence or from a subset of the words of said de-Bruijn sequence.

A coil made of a coiled metal strip, in particular an aluminum strip, having a marking on a flat side of the metal strip. In order to be able, inter alia, to clearly identify the strip segments severed from the coil it is proposed that the marking, for allocating strip segments severed from the coil to the coil and the original position of the marking on the coil, comprises an information track, preferably extending across the entire strip length of the metal strip having a de-Bruijn sequence of successively arranged words of said de-Bruijn sequence or from a subset of the words of said de-Bruijn sequence.

A coil made of a coiled metal strip, in particular an aluminum strip, having a marking on a flat side of the metal strip. In order to be able, inter alia, to clearly identify the strip segments severed from the coil it is proposed that the marking, for allocating strip segments severed from the coil to the coil and the original position of the marking on the coil, comprises an information track, preferably extending across the entire strip length of the metal strip having a de-Bruijn sequence of successively arranged words of said de-Bruijn sequence or from a subset of the words of said de-Bruijn sequence.

An apparatus for preparing a tube end for rod drawing with a floating mandrel has a releasable holder for the tube end centered on an axis, a frustoconical and spreadable floating mandrel, and a device for inserting the mandrel into the tube end and spreading the mandrel to flare the tube end. The apparatus further has a feed mechanism for inserting the floating mandrel into the tube end and/or a deforming device for making at least one indentation in the tube for holding the floating mandrel.

The invention relates to a device and a method for producing a pipe (1) from a hollow block (2) which has an opening (3). The device has a rolling mill (30) for rolling the hollow block (2) via a rolling rod (21) introduced into the opening (3) of the hollow block (2), whereby the pipe (1) is produced. A retaining device (70) for retaining the pipe (1) is provided behind the rolling mill (30), and the device is further designed such that the rolling rod (21) can be drawn out of the pipe (1) after the rolling process while the pipe (1) is retained by the retaining device (70).