Method and tools for manufacturing of seamless tubular shapes, especially tubes

1. A method for manufacturing a seamless tubular shape formed by continuously-produced flash, comprising the step of plunging a consumable rod against a rigid anvil, wherein the consumable rod has a longitudinal axis and there is a relative rotational speed between the consumable rod and the anvil about an axis of rotation that is coincident with the axis of the consumable rod, and where said continuously-produced flash is obtained by viscoplastic deformation of the consumable rod against the rigid anvil in full open die condition, and where the rigid anvil is a plate unit with no through holes in the zone in contact with the consumable rod.

2. A method according to claim 1 , where the consumable rod has a longitudinal axis and there is a relative rotational speed (Vz) between the consumable rod and the anvil about an axis of rotation that is coincident with the axis of the consumable rod.

3. A method according to claim 1 , where the consumable rod has a longitudinal axis coincident with an axis of symmetry of the flash.

4. A method according to claim 1 where the consumable rod is cylindrical with a diameter along a longitudinal axis thereof.

5. A method according to claim 4 where the consumable rod is cylindrical with a constant-diameter along the longitudinal axis thereof.

6. A method according to claim 4 where the consumable rod is cylindrical with a variable-diameter along the longitudinal axis thereof.

7. A method according to claim 1 where plunging of the rotating consumable rod or anvil is performed using an alternative selected one of a force control mode and a speed control mode, and where it is possible to change the selected one during plunging.

8. A method according to claim 1 where the outer diameter and thickness of the flash is set by controlling of at least one of the following parameters:

plunge force or plunge speed;

relative rotational speed between the consumable rod and the rigid anvil;

diameter of the consumable rod;

thermo-physical properties of the consumable rod material;

thermo-physical properties of the optionally consumable anvil material;

boundary conditions (e.g. geometrical, mechanical and thermal conditions) applied to the

flash.

9. A method according to claim 1 including the following steps:

starting the relative rotation between the consumable rod and the rigid anvil;

bringing the consumable rod into contact with rigid anvil under speed control;

starting the plunging period under an alternative one of force control and speed control;

adjusting the relative rotation, control mode and its value towards the final desired tubular shape;

and thereafter selectively obtaining a tube or a cannister, where

obtaining a tube comprises extracting both an open end and a closed end from the tubular shape remaining at the completion of the plunging phase; and

obtaining a canister comprises extracting only the open end from the tubular shape remaining at the completion of the plunging phase.

10. A method according to claim 1 where the consumable rod and flash independently of each other are free or guided, to prevent loss of stability, during the plunging phase.

11. A method according to claim 1 where the consumable rod is plunged with the support of a rigid non-consumable rod, clamped to the consumable rod, and used as a plunger of the consumable rod, during the plunging phase.

12. A method according to claim 1 where the rigid anvil is a non-consumable plate unit.

13. A method according to claim 1 where the rigid anvil is a consumable plate unit.