Tube having a length of more than 10 m suitable for high-pressure applications with internal pressure of 2 bar or more, and which is not afflicted with disadvantages exhibited by tubes produced by conventional drawing or cold pilger milling methods. The tube has a wall thickness equal to or larger than the internal diameter, an axial length of 12 m or more, a tensile strength Rm of 850 N/mm.sup.2 or more, and a mean roughness index Ra of the inner wall surface of 0.8 ?m or less. Furthermore, a method of manufacturing such a tube forms a hollow into a tubular intermediate in a first forming step according to the cold forming method, the tubular intermediate thus obtained is annealed, and the annealed tubular intermediate is formed into a tube in a second forming step according to the cold forming method.

The present invention relates to a method for forming a hollow 26 of a ferritic FeCrAI alloy into a tube 2. While tubes made of powder metallurgical, dispersion hardened, ferritic FeCrAI alloys are commercially available, hollows made of FeCrAI alloys so far can hardly be formed into tubes of small dimensions. The major reason for the problems in forming hollows of a ferritic FeCrAI alloy into a finished product is that FeCrAI alloys are brittle. It is therefore an aspect of the present invention to provide a tube 2 made of a ferritic FeCrAI alloy having arbitrary small dimensions. Furthermore, it is an aspect of the present invention to provide a machine 1 and a method for forming a tubular hollow 26 into a finished tube 2 of a ferritic FeCrAI alloy. At least one of the above aspects is addressed by a method for forming a hollow into a tube 2 comprising the steps providing the hollow 26 of a ferritic FeCrAI alloy, heating the hollow 26 to a temperature in a range from 90 C. to 150 C., and forming the heated hollow 26 by pilger milling or drawing into the tube.

The present invention relates to a method for forming a hollow 26 of a ferritic FeCrAI alloy into a tube 2. While tubes made of powder metallurgical, dispersion hardened, ferritic FeCrAI alloys are commercially available, hollows made of FeCrAI alloys so far can hardly be formed into tubes of small dimensions. The major reason for the problems in forming hollows of a ferritic FeCrAI alloy into a finished product is that FeCrAI alloys are brittle. It is therefore an aspect of the present invention to provide a tube 2 made of a ferritic FeCrAI alloy having arbitrary small dimensions. Furthermore, it is an aspect of the present invention to provide a machine 1 and a method for forming a tubular hollow 26 into a finished tube 2 of a ferritic FeCrAI alloy. At least one of the above aspects is addressed by a method for forming a hollow into a tube 2 comprising the steps providing the hollow 26 of a ferritic FeCrAI alloy, heating the hollow 26 to a temperature in a range from 90 C. to 150 C., and forming the heated hollow 26 by pilger milling or drawing into the tube.

This disclosure describes various configurations and components for bimetallic and trimetallic claddings for use as a wall element separating nuclear material from an external environment. The cladding materials are suitable for use as cladding for nuclear fuel elements, particularly for fuel elements that will be exposed to sodium or other coolants or environments with a propensity to react with the nuclear fuel.

Cold pilger rolling mill for cold forming a hollow into a strain hardened tube with a roll stand with rollers mounted pivotably thereon. Efficient milling of long hollows is enabled without reducing the quality of the manufactured tubes. The cold pilger rolling mill has an unwinding device, wherein the unwinding device is arranged and in the feed direction of the hollow is located in front of the front mandrel thrust block such that at the unwinding device a spindle being rotatable around an axis being perpendicular to the feed direction of the hollow with the hollow wound thereon is receivable and in an operation of the cold pilger rolling mill the hollow is unwindable and feedable between the chuck of the front mandrel thrust block and the mandrel bar into the feed clamping sledge and the roll stand.

Pilger rolling mill for working a hollow into a tube has a first roll stand mounted linearly moveable in a direction of motion. Translational motion of the roll stand causes rotational motion of the drive gear due to the cogging of the drive gear with the gear rack and, hence, also rotational motion of the roller arranged on the shaft of the drive gear and rotational motion of the other one of the two rollers in the opposite direction. Roll stand is connected with a crank drive and rotational motion of a motor drive is transformed into an oscillating translational motion of the roll stand by a connecting rod. Gear rack holder allows adjustment of the pilger rolling mill with respect to tube diameters of finished rolled tubes by arranging the first roll stand exchangeable by a second roll stand with a second dimension being different from the first dimension.

A cold pilger rolling mill for forming a tube shell to a tube includes a feed clamping carriage for receiving the tube shell and with a drive that is arranged to move the feed clamping carriage such that during the operation of the cold pilger rolling mill the tube shell moves step-by-step in the direction of the tool. A control and a sensor detect a measure of a force exerted during the operation of the cold pilger rolling mill by the tool onto the tube shell, and wherein the control is connected to the drive and the sensor. The control is arranged to regulate, during the operation of the cold pilger rolling mill, the step length per advance step with which the drive moves the feed clamping carriage to the tool as a function of the measure for the force, which measure is detected by the sensor.

The state of the art discloses cold rolling mills comprising a roll stand, at least one roll rotatably mounted to the roll stand, a feed clamping saddle for feeding a blank, and a first drive for the feed clamping saddle. Those cold rolling mills have ball spindle drives with a high rate of wear as the drive for the feed clamping saddle. In comparison the object of the present invention is to provide a cold rolling mill whose drive for the feed clamping saddle involves no or only very slight wear and which in addition permits a slow movement of the feed clamping saddle. According to the invention that object is attained by a cold rolling mill which has a direct electromechanical linear drive for the feed clamping saddle.

The state of the art discloses cold rolling mills comprising a roll stand, at least one roll rotatably mounted to the roll stand, a feed clamping saddle for feeding a blank, and a first drive for the feed clamping saddle. Those cold rolling mills have ball spindle drives with a high rate of wear as the drive for the feed clamping saddle. In comparison the object of the present invention is to provide a cold rolling mill whose drive for the feed clamping saddle involves no or only very slight wear and which in addition permits a slow movement of the feed clamping saddle. According to the invention that object is attained by a cold rolling mill which has a direct electromechanical linear drive for the feed clamping saddle.

A device for cold working pipe elements has two or more cams, each having a gear which meshes with a pinion to turn all of the cams. Each cam has a cam surface with a region of increasing radius and may have a region of constant radius extending around a cam body. Each cam also has a traction surface extending around a cam body. A discontinuity in each cam surface is aligned with a gap in the traction surface of each cam. The discontinuities and gaps provide clearance for insertion and removal of the pipe element between the cams to form a circumferential groove when the cams are rotated. A cup adjacent the pinion is movable along the pinion axis to engage and disengage from a stop surface on one of the cams. Engagement between the cup and a stop surface prevents rotation of the cam.