The present inventive concept provides a method for manufacturing a multi-layered nuclear fuel cladding pipe, comprising the steps of: providing a preliminary cladding pipe in which an inner pipe having a rod-shaped insertion body inserted thereinto is disposed in an outer pipe; reducing the diameter of the preliminary cladding pipe by applying pressure from the outside to the inner side of the preliminary cladding pipe; and removing the insertion body from the inner pipe by providing a force in the direction in which the insertion body extends, wherein the inner pipe and the outer pipe may be formed of different metals from each other.

A device to process a blank (3) that includes at least one outer shaping tool (8) that may be radially positioned or radially displaced. An inner shaping tool (9) is mounted co-axially to the main machine axis (x) of the main spindle (1.1). The inner shaping tool (9) may be axially displaced and/or axially positioned with respect to the axial position of the outer shaping tools (8).

A device to process a blank (3) that includes at least one outer shaping tool (8) that may be radially positioned or radially displaced. An inner shaping tool (9) is mounted co-axially to the main machine axis (x) of the main spindle (1.1). The inner shaping tool (9) may be axially displaced and/or axially positioned with respect to the axial position of the outer shaping tools (8).

The present invention relates to a multi-stand rolling mill (1) for tubular bodies. The rolling mill comprises a first section (10) for rolling on mandrel defined by a first plurality of rolling stands (15, 15, 15) arranged in sequence along a rolling axis (100). According to the invention, the rolling mill also comprises a second rolling section without mandrel, arranged down-stream of said first section, which comprises a second plurality of stands (25, 25, 26, 27, 26, 27) arranged in sequence along said rolling axis (100). Each stand (25, 25, 26, 27, 26, 27) of said second section (20) comprises three rollers having rotation axes which are arranged at 120? from one another. The rotation axes for each stand (25, 25, 26, 27, 26, 27) are rotated by 180? with respect to corresponding rotation axes of an adjacent stand. According to the invention, at least one stand of said second section (20) comprises a motorized roller having a vertical rotation axis.

The present invention relates to a multi-stand rolling mill (1) for tubular bodies. The rolling mill comprises a first section (10) for rolling on mandrel defined by a first plurality of rolling stands (15, 15, 15) arranged in sequence along a rolling axis (100). According to the invention, the rolling mill also comprises a second rolling section without mandrel, arranged down-stream of said first section, which comprises a second plurality of stands (25, 25, 26, 27, 26, 27) arranged in sequence along said rolling axis (100). Each stand (25, 25, 26, 27, 26, 27) of said second section (20) comprises three rollers having rotation axes which are arranged at 120? from one another. The rotation axes for each stand (25, 25, 26, 27, 26, 27) are rotated by 180? with respect to corresponding rotation axes of an adjacent stand. According to the invention, at least one stand of said second section (20) comprises a motorized roller having a vertical rotation axis.

A rolling plant (R) for rolling tubes having a multi-stand rolling mill (5) with two or more rolls, in order to implement a controlled speed mandrel rolling process, comprises a hooking and releasing device (61) which is arranged in the inlet area of the rolling mill (5) to cooperate with the rear tang of the mandrel (31) and a hooking and releasing device (71) which is arranged in the outlet area of the rolling mill (5) to cooperate with the front tang of the mandrel (31) in coordinated manner with the first hooking and releasing device (61).

A rolling plant (R) for rolling tubes having a multi-stand rolling mill (5) with two or more rolls, in order to implement a controlled speed mandrel rolling process, comprises a hooking and releasing device (61) which is arranged in the inlet area of the rolling mill (5) to cooperate with the rear tang of the mandrel (31) and a hooking and releasing device (71) which is arranged in the outlet area of the rolling mill (5) to cooperate with the front tang of the mandrel (31) in coordinated manner with the first hooking and releasing device (61).

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).

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).

A manufacturing method of a seamless metal pipe includes: preparing a plurality of mandrel bars in which lengths of work portions which come into contact with a hollow shell during elongating are different from one another; selecting a mandrel bar including a work portion having a length corresponding to the number of stands used in thickness reduction, among the plurality of mandrel bars; inserting the mandrel bar selected in the selecting into the hollow shell; and performing the elongating on the hollow shell into which the mandrel bar is inserted. Moreover, in the elongating, outer diameter reduction is performed by one of a preceding-stage stand group and a succeeding-stage stand group and the thickness reduction is performed by the other of the preceding-stage stand group and the succeeding-stage stand group, or the thickness reduction is performed by both of the preceding-stage stand group and the succeeding-stage stand group.