A method of evaluating deformability of steel pipe with which deformability can be evaluated regardless of whether the pitch of pipe expansion is coarse or fine, and a method of manufacturing steel pipe using the method of evaluating deformability, are disclosed. A method of evaluating deformability of steel pipe according to the present invention is a method for evaluating deformability of a steel pipe manufactured through a pipe expanding step performed using a die. The method of evaluating deformability of steel pipe includes an outer shape acquiring step of measuring a shape of the steel pipe to acquire an outer shape, a power spectrum acquiring step of acquiring a power spectrum from a wavy shape of the acquired outer shape, and a determining step of integrating the acquired power spectrum for a predetermined wavelength range and determining deformability on the basis of the resulting integral.

A pipe grooving device includes an assembly adapted to receive an end of the pipe. The assembly includes a cup which surrounds a pipe end stop. The cup and the pipe end stop may be mounted on a fixed pinion about which a carriage rotates. The carriage carries geared cams which engage the pinion and rotate synchronously when the carriage rotates relatively the pinion. The cams engage a pipe element received by the cup and form a circumferential groove in the pipe element. The cup and the pipe end stop move independently of one another axially along a pinion shaft to actuate rotation of the carriage. The cup accommodates dimensional pipe diameter tolerances and mitigates pipe flare and maintains pipe roundness during the grooving process.

A pipe grooving device includes an assembly adapted to receive an end of the pipe. The assembly includes a cup which surrounds a pipe end stop. The cup and the pipe end stop may be mounted on a fixed pinion about which a carriage rotates. The carriage carries geared cams which engage the pinion and rotate synchronously when the carriage rotates relatively the pinion. The cams engage a pipe element received by the cup and form a circumferential groove in the pipe element. The cup and the pipe end stop move independently of one another axially along a pinion shaft to actuate rotation of the carriage. The cup accommodates dimensional pipe diameter tolerances and mitigates pipe flare and maintains pipe roundness during the grooving process.

An inner roller used for roll forming pipe elements has a flange extending radially from a body. The flange has a surface divided into annular surface portions. The surface portions have orientation angles measured relatively to the axis of rotation of the inner roller. The orientation angles of surface portions farther from the body have greater orientation angles than the surface portions nearer to the body to mitigate adverse frictional effects between the pipe element and the flange during roll forming.

A pipe extending from a first side toward a second side includes a side wall and a spool. The spool formed in the side wall is bent so as to protrude from an outer circumferential surface of the pipe, and extends to surround the outer circumferential surface. The spool includes a first portion located on the first side and a second portion located on the second side. There is a clearance between the first portion and the second portion in a top region of the spool, and the first portion and the second portion substantially abut each other in a base region.

A system comprises a tube and a bender. The tube comprises a first cylindrical portion and a second cylindrical portion. An undulated portion is disposed between the first cylindrical portion and the second cylindrical portion. Alternatively, the tube can comprise a plurality of cylindrical portions and undulated portions. The bender comprises a plurality of L-shaped brackets and a plurality of U-shaped brackets, and further includes a driving rod subassembly.

A combination of roller tools is used to cold work a pipe element and impart a desired shape to the sidewall. The roller tools are movably mounted on a frame. Segments of the roller tools align with one another during operation. The roller tools are used in a method of roll forming wherein the sidewall of the pipe element is compressed between the rollers.

A combination of roller tools is used to cold work a pipe element and impart a desired shape to the sidewall. The roller tools are movably mounted on a frame. Segments of the roller tools align with one another during operation. The roller tools are used in a method of roll forming wherein the sidewall of the pipe element is compressed between the rollers.

A form-rolling device for processing a tubular member may include a shaft rotatable around a first axis, a first grooving portion that protrudes from an outer circumference of the shaft; a second grooving portion that is rotatable around a second axis parallel to the first axis; a flange-shaped tube-end positioning member that is attached to a position of the outer circumference of the shaft nearer to a base end than the first grooving portion, and a supporting member that supports an outer circumference of a ring member held on an outer circumference of the tubular member.

A form-rolling device for processing a tubular member may include a shaft rotatable around a first axis, a first grooving portion that protrudes from an outer circumference of the shaft; a second grooving portion that is rotatable around a second axis parallel to the first axis; a flange-shaped tube-end positioning member that is attached to a position of the outer circumference of the shaft nearer to a base end than the first grooving portion, and a supporting member that supports an outer circumference of a ring member held on an outer circumference of the tubular member.