To enhance forming performance enhanced in square tube forming of forming a round tube into a square tube by passing the round tube through a plurality of roll stands arranged in a raw tube forming direction. To give a high degree of multi-usability to a square tube forming device. To suppress the entire length of a roll stand array. A first flat roll stand 20A and a second flat roll stand 20B of rolling directions orthogonal to each other are arranged alternately in a forming direction to form a roll stand array 10. Each of the roll stands 20A and 20B includes roll gap adjusting means by which a rolling amount is independently settable, and one of the first flat roll stand 20A and the second flat roll stand 20B adjacent to each other is driven to rotate by roll driving means 40. A forming rolling amount distribution is allocated individually as a rolling amount at each of the roll stands 20A and 20B. The forming rolling amount distribution is determined in advance for stands from a first-stage stand to a final-stage stand in response to the outer diameter, thickness, and material of a forming target raw tube and an intended dimension of a square tube as a product.

To a fulcrum roll unit portion in a workpiece, a corresponding initial curvature radius is applied, and to a bending roll unit portion in a workpiece, a corresponding design curvature radius is applied. To an intermediate unit portion in a workpiece, an intermediate curvature radius set so as to continuously change from the initial curvature radius to the design curvature radius is applied. At least one of the fulcrum roll and the bending roll is moved on the basis of an integrated value obtained by integrating the amount of change in bending position in each of the intermediate unit portion and the bending roll unit portion.

A hot and cold composite formed square and rectangular steel tube and a production method for the same are provided. The radius of an outer corner of the square and rectangular steel tube meets the following conditions: when t is less than or equal to 6 mm, R is greater than 0 and less than 2.0 t; when t is greater than 6 mm and less than or equal to 10 mm, R is greater than 0 and less than 2.5 t; when t is greater than 10 mm, R is greater than 0 and less than 3.0 t, wherein t is the wall thickness of a straight tube part of the square and rectangular steel tube; R is the radius of each of the outer corners of the four corners of the square and rectangular steel tube; and the wall thickness of each corner of the square and rectangular steel tube is between 1.0 t and 1.8 t.

An automatically adjusting auto gauge system comprises a servo motor that provides rotational motion; at least one of a gearbox and linear actuator driven by the one or more servo motors to transfer the rotational motor of the servo motor to linear motion; a group of roll former passes, each including a cam arm, an eccentric cam, a push rod, a top set of roll tooling, a bottom set of roll tooling; a bar operably coupled to the gearbox and the cam arms of the group of roll former passes, the bar driven by the gearbox to impart linear motion to the cam arms, which in turn imparts rotational motion to each eccentric cam, which in turn imparts linear motion, raising or lowering the top set of roll tooling via the push rod, adjusting a gap between the top and bottom sets of roll tooling.

There are provided an electric resistance welded steel pipe for producing a high strength hollow stabilizer excellent in fatigue resistance and a high strength hollow stabilizer. In an electric resistance welded steel pipe (5) for producing a hollow stabilizer, an internal weld bead cut portion (30) has a three-peak shape and a depth (H) of a trough portion (30a) of the three-peak shape is 0.3 mm or less and an angle () formed by a central portion in the circumferential direction of the trough portion (30a) and the top of right and left peak portions (30b, 30c) located on both the right and left sides of the trough portion (30a) is 160 or more and less than 180.

Changing of a horizontal roll in a horizontal roll stand involving readjustment of an amount of pressing is to be done readily and promptly. In order to achieve this, a horizontal roll stand 10 with a pair of built-in upper and lower horizontal rolls 11 is configured to retreat toward one side across a forming line. A fixed stand 40 stands upright on a counter-retreating side of the forming line. An overhang part 42 of the fixed stand 40 jutting out over the forming line is provided with a pressure device 43 that applies a pressing force to the horizontal rolls 11. The horizontal roll stand 10 includes a horizontal roll housing 12 with an opened top, receives the pressing force from the pressure device 43 via the opened top, and retreats to the outside of the forming line while the pressure device 43 is left on the forming line. The overhang part 42 of the fixed stand 40 is engaged with the horizontal roll housing 12 of the horizontal roll stand 10 to support the horizontal roll housing 12 in the forming line.

Changing of a horizontal roll in a horizontal roll stand involving readjustment of an amount of pressing is to be done readily and promptly. In order to achieve this, a horizontal roll stand 10 with a pair of built-in upper and lower horizontal rolls 11 is configured to retreat toward one side across a forming line. A fixed stand 40 stands upright on a counter-retreating side of the forming line. An overhang part 42 of the fixed stand 40 jutting out over the forming line is provided with a pressure device 43 that applies a pressing force to the horizontal rolls 11. The horizontal roll stand 10 includes a horizontal roll housing 12 with an opened top, receives the pressing force from the pressure device 43 via the opened top, and retreats to the outside of the forming line while the pressure device 43 is left on the forming line. The overhang part 42 of the fixed stand 40 is engaged with the horizontal roll housing 12 of the horizontal roll stand 10 to support the horizontal roll housing 12 in the forming line.

An apparatus for the support and the controlled advancement of a sheet in a bending machine for forming a cylindrical or conical structure, in particular of a truncated cone structure, comprises a base structural frame adapted to be positioned upstream of said bending machine, with respect to an advancement direction of the sheet, a plurality of conveying modules which can be mounted, removable, on the structural frame so as to generate a plan of modular support and advancement which can be configured geometrically according to the shape and dimensions of the sheet to be produced; the modular support and advancement plane is geometrically configured to keep the sheet metal part supported by the plane in a flat condition; an lifting and tilting device configured to vary the position of the structural frame, supporting the conveying modules, from a horizontal lying position to an inclined lying position in which the support and advancement plane is inclined downwards towards the bending machine; repositioning and position correcting members configured to orient and arrange the sheet in a correct position before starting a bending cycle and configured to correct, during the bending cycle, the position of the sheet to impose it a predetermined advancement trajectory towards and through the bending machine. The relative method is also envisaged.

An apparatus for the support and the controlled advancement of a sheet in a bending machine for forming a cylindrical or conical structure, in particular of a truncated cone structure, comprises a base structural frame adapted to be positioned upstream of said bending machine, with respect to an advancement direction of the sheet, a plurality of conveying modules which can be mounted, removable, on the structural frame so as to generate a plan of modular support and advancement which can be configured geometrically according to the shape and dimensions of the sheet to be produced; the modular support and advancement plane is geometrically configured to keep the sheet metal part supported by the plane in a flat condition; an lifting and tilting device configured to vary the position of the structural frame, supporting the conveying modules, from a horizontal lying position to an inclined lying position in which the support and advancement plane is inclined downwards towards the bending machine; repositioning and position correcting members configured to orient and arrange the sheet in a correct position before starting a bending cycle and configured to correct, during the bending cycle, the position of the sheet to impose it a predetermined advancement trajectory towards and through the bending machine. The relative method is also envisaged.

The disclosure relates to a method for pre-shaping sheet metal (1) in strip- or panel-form having a flat cross-sectional profile into a circular arc-shaped cross-sectional profile, in a pre-shaping section (3) of a plant for producing open-seam pipes. The circular arc-shaped cross-sectional profile is provided to the sheet metal (1) in the pre-shaping section (3) by means of roll profiling in a plurality of successive bending steps in a transport direction. The cross-sectional profile is created by step-by-step bending of individual circular arc portions (8) from an outer edge of the sheet metal (1) toward a center line (7) such that the individual circular arc portions (8) directly adjoin one another or at least partially overlap. The disclosure further relates to a device for carrying out the method.