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 (θ) 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°.

A joint module for forming a joint section from a tube that is formed at an operational speed by a roll forming machine may include a carriage positioned proximate the back end of the roll forming machine and configured to move in a longitudinal direction relative to the back end. A pleat die assembly may be mounted on the carriage and configured to repeatedly engage the tube to form a series of pleats thereby bending the tube to form the joint section, and a crimp die assembly may be mounted on the carriage and configured to engage the tube to crimp an end of the joint section and to sever the end of the joint section from the tube. The carriage may move relative to the frame while the tube is engaged with at least one of the crimp die assembly and the pleat die assembly.

A roll forming machine for continuously forming a sheet into a joint section of a tube may include a plurality of roller stations arranged longitudinally on a frame and configured to bend the sheet to form the tube, and a carriage slidably secured to the frame. A pleat die assembly may be mounted on the carriage and can be configured to repeatedly engage the tube to form a series of pleats thereby bending the tube to form the joint section. A crimp die assembly may be mounted on the carriage and can be configured to engage the tube to crimp an end of the joint section and sever the end of the joint section from the tube. The carriage may be configured to be selectively moved relative to the frame while the tube is engaged with at least one of the crimp die assembly and the pleat die assembly.

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.

In one embodiment, the method includes providing a double sheet metal element including the two sheet metal end sections; and creating a connecting section along the connecting line. The creation of the connecting section includes introducing a first depression into the double sheet metal element, and creating a first folded section of the double sheet metal element. The method further includes orienting the connecting section relative to an extension plane of the double sheet metal element so that the connecting section extends perpendicularly to the extension plane.

A multiple-winding pipe forming device for forming a wound pipe, the multiple-winding pipe forming device comprising: a plurality of pairs of forming rollers curling a metal sheet and winding the metal sheet into a roll shape; and a mandrel fabricated of metal, the mandrel including: a shaft disposed inside the metal sheet wound in the roll shape, one end side of the shaft being retained, which one end side is disposed upstream in a feeding direction of the metal sheet, and a working portion including a taper portion that increases in diameter from upstream to downstream in the feeding direction, wherein the taper portion is disposed at a position at which the metal sheet wound in the roll shape is sandwiched by, of the plurality of pairs of forming rollers, a pair of the forming rollers that is disposed at a downstream side in the feeding direction.

A multiple-winding pipe forming device for forming a wound pipe, the multiple-winding pipe forming device comprising: a plurality of pairs of forming rollers curling a metal sheet and winding the metal sheet into a roll shape; and a mandrel fabricated of metal, the mandrel including: a shaft disposed inside the metal sheet wound in the roll shape, one end side of the shaft being retained, which one end side is disposed upstream in a feeding direction of the metal sheet, and a working portion including a taper portion that increases in diameter from upstream to downstream in the feeding direction, wherein the taper portion is disposed at a position at which the metal sheet wound in the roll shape is sandwiched by, of the plurality of pairs of forming rollers, a pair of the forming rollers that is disposed at a downstream side in the feeding direction.

A device for shaping and clamping a rim extruding strip is disclosed herein. It comprises a first pressure plate, a second pressure plate, a power source having a power output shaft and a first teeth part disposed on the power output shaft, wherein the power output shaft has a first end assembled to the first pressure plate and a second end passing through the second pressure plate; an actuation rod having a second teeth part, a first end passing through the first pressure plate, and a second end assembled to the second pressure plate; and a gearing wheel disposed between the first teeth part of the power output shaft and the second teeth part of the actuation rod.

A part of a plate member is machined to remove material therefrom so as to obtain an intermediate product having a thickness difference. Then, the intermediate product is bent and both edges thereof are joined to obtain a cylindrical body. Further, a first heat treatment of heating the cylindrical body is performed. Then, through holes penetrating from the outside to the inside of the peripheral wall of the cylindrical body are formed. Pipe parts are joined to the tubular body thus obtained to form a tubular member. This tubular member is subjected to a second heat treatment.

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.