A method for manufacturing a pipe includes: press-forming a plate member into a U shape; and press-forming the plate member formed into the U shape into an O shape. The pipe includes a pipe body and a tapered part tilted radially inward and protruding from one end of the pipe body. Before the plate member is press-formed into the U shape, a boundary between a portion of the plate member corresponding to the pipe body and a portion of the plate member corresponding to the tapered part is pressed from a surface of the plate member corresponding to an inner peripheral surface of the pipe to bend the portion of the plate member corresponding to the tapered part toward the surface of the plate member corresponding to the inner peripheral surface of the pipe.

Spiral forming devices, systems, and methods can be used to join edges of a of a stock material, in a curved configuration, along one or more joints to form tubular structures, such as conical and/or cylindrical structures (e.g., frusto-conical structures). A planar form of the stock material can be formed from a plurality planar sheets coupled to one another in an abutting relationship. By controlling relative orientation and shapes of the plurality of planar sheets forming the stock material and/or by controlling a position of a roll bender used to curve the planar form of the stock material into the curved configuration, the curved configuration of the stock material can be controlled through transitions between sheets to facilitate rolling the sheets to a desired diameter with a reduced likelihood of dimples or other errors and to facilitate fit up between adjacent sheets in the curved configuration.

There is provided a method of manufacturing a variable wall thickness steel pipe with a hollow tubular raw pipe. The method of manufacturing a variable wall thickness steel pipe includes locking the raw pipe in a die by thrusting a plug into the raw pipe from an one end side, so as to expand an outer shape on the one end side in a state, where the raw pipe is disposed inside the die and movement of the raw pipe in a longitudinal direction is restricted; and performing ironing in which an inner shape of the raw pipe is expanded while the outer shape is maintained so that a thin portion is formed by further thrusting the plug toward the other end side of the raw pipe while the locked state of the raw pipe is maintained, whereas the restriction on the raw pipe is relaxed.

Feeding stock used to form a tapered structure into a curving device such that each point on the stock undergoes rotational motion about a peak location of the tapered structure; and the stock meets a predecessor portion of stock along one or more adjacent edges.

Spiral forming devices, systems, and methods can be used to join edges of a of a stock material, in a curved configuration, along one or more joints to form tubular structures, such as conical and/or cylindrical structures (e.g., frusto-conical structures). A planar form of the stock material can be formed from a plurality planar sheets coupled to one another in an abutting relationship. By controlling relative orientation and shapes of the plurality of planar sheets forming the stock material and/or by controlling a position of a roll bender used to curve the planar form of the stock material into the curved configuration, the curved configuration of the stock material can be controlled through transitions between sheets to facilitate rolling the sheets to a desired diameter with a reduced likelihood of dimples or other errors and to facilitate fit up between adjacent sheets in the curved configuration.

A method of production of a shaped article able to suppress occurrence of shaping defects, that is, a method of production of a shaped article including a first step of press-forming a metal plate (1a) into a U-shape to obtain a U-shaped article (1b) having a bottom part (2) straight extending in a longitudinal direction and a second step of press-forming the U-shaped article (1b) to bend it in the longitudinal direction so that the bottom part (2) of the part projects to the inside and obtain a U-cross-section bent article (1c).

A control system for forming a tapered structure includes a sensor providing feedback for a machine for forming a tapered structure including at least three rolls having at least one bend roll and at least two guide rolls. The guide rolls may include rollette banks having a plurality of rollettes. The machine may also include an adjustment mechanism to position at least one of the rolls, where a diameter of the tapered structure being formed is controlled by relative positions of the rolls. The machine may also include a joining element to join edges of a stock of material together as it is rolled through the rolls to form the tapered structure. The control system may also include a controller to receive feedback from the sensor and to send a control signal based on the feedback to the adjustment mechanism for positioning at least one of the rolls.

A control system for forming a tapered structure includes a sensor providing feedback for a machine for forming a tapered structure including at least three rolls having at least one bend roll and at least two guide rolls. The guide rolls may include rollette banks having a plurality of rollettes. The machine may also include an adjustment mechanism to position at least one of the rolls, where a diameter of the tapered structure being formed is controlled by relative positions of the rolls. The machine may also include a joining element to join edges of a stock of material together as it is rolled through the rolls to form the tapered structure. The control system may also include a controller to receive feedback from the sensor and to send a control signal based on the feedback to the adjustment mechanism for positioning at least one of the rolls.

To improve forming performance in a smart mill allowing implementation of required forming by moving a forming tool arranged in a stand of a pipe mill automatically to a predetermined position.

Non-drive type breakdown rolls BD exclusive to bending are arranged in multiple stands. Drive roll DR stands exclusive to driving are arranged in stages in front of and behind each DR stand. The drive roll DR is configured to apply thrust to a central portion of a raw material using an upper flat roll and a lower flat roll, and has thrust control means and driving rotation number control means for applying thrust required for passage through the step using the drive rolls DR in multiple stages entirely and controlling the thrust. Applying the thrust under pressure control to the central portion of the material using the upper and lower flat rolls at the DR stand provides a definite roll reference diameter and feeds the raw material at a constant speed and thrust, making it possible to ensure thrust required for various product diameters or thicknesses.

Spiral forming methods can be used to join edges of a rolled material along a spiral joint to form conical and/or cylindrical structures. Alignment of the edges of the rolled material can be controlled in a wrapping direction as the material is being joined along the spiral joint to form the structure. By controlling alignment of the edges of the material as the edges of the material are being joined, small corrections can be made over the course of forming the structure facilitating control over geometric tolerances of the resulting spiral formed structure.