A method for producing a steel material for line pipes including heating a steel having a specific composition to a temperature of 1000 C. to 1200 C.; performing hot rolling such that a cumulative rolling reduction ratio in a non-recrystallization temperature range is 60% or more, a cumulative rolling reduction ratio in a temperature range of (a rolling finish temperature +20 C.) or less is 50% or more, and a rolling finish temperature is the Ar.sub.3 transformation point or more and 790 C. or less; subsequently performing accelerated cooling from a temperature of the Ar.sub.3 transformation point or more, at a cooling rate of 10 C./s or more, to a cooling stop temperature of 200 C. to 450 C.; and then performing reheating such that the temperature of a surface of the steel plate is 350 C. to 550 C. and the temperature of the center of the steel plate is less than 550 C.

A pipe body, wherein the pipe body (10) has a welded portion (11) at both ends of the pipe body, aligned in a widthwise direction of the pipe body (10). The thickness of the welded portion (11) decreases gradually from the inside to the outside of the pipe, and an outer end of the welded portion (11) is located at a center portion of the pipe body (10) in a thickness direction. The configuration of the welding structure enhances the strength of the welded portion of the pipe, so that the pipe will not crack easily when it is reworked by flaring or bending, thus having high reworkability. In addition, a pipe (100) made of the pipe body (10) and a method of making the pipe (100) are disclosed.

An apparatus that manufactures a closed-structure part includes a bottom portion and left and right side wall portions, including a press-forming die that form a plurality of first out-of-plane deformed portions and bent portions, the first out-of-plane deformed portions being formed in a region of a workpiece corresponding to the bottom portion and arranged along a longitudinal direction, each of the first out-of-plane deformed portions having a recessed shape or a protruding shape; a pad and a punch that squash the first out-of-plane deformed portions by clamping the region of the workpiece corresponding to the bottom portion therebetween, a cross-sectional shape of a pressing portion of the punch being curved along the longitudinal direction; and bending dies that bend the bent portions by pressing the punch into a space therebetween while the region of the workpiece corresponding to the bottom portion is clamped between the pad and the punch.

The invention discloses a foundation pile having at least two interconnected part-cylinder segments which are each produced from a steel plate having a length extent and a width extent, wherein the foundation pile is characterized in that the respective part-cylinder segments are produced by bending the steel plates along their width extent, with the result that end edges extending along the width extent of the part-cylinder segments have a bending, in that a height extent of the respective part-cylinder segments is greater than their width extent, and in that the longitudinal edges of the part-cylinder segments that extend along the height extent of the part-cylinder segments are arranged parallel to one another. The present invention further discloses a method for producing a foundation pile according to the invention.

The present invention provides an integrated method for forming and performance control of NiAl alloy thin-walled tubular parts. A Ni/Al laminated foil tube is obtained after Ni foils and Al foils are alternately laminated and coiled; and the Ni/Al laminated foil tube is subjected to plastic forming, reaction synthesis and densification treatment in a gas bulging forming die to obtain a NiAl alloy thin-walled tubular part. The present invention solves the problem in the prior art that the preparation of an existing NiAl alloy sheet and the formation of the thin-walled tubular part from the sheet feature difficulty in material flow and structural performance control and a complicated process. Data of embodiments shows that the NiAl alloy thin-walled tubular parts obtained by using the method of the present invention has a high forming rate, high dimensional precision, uniform composition distribution, good tubular part compactness and no defects on the surface.

A pipe is formed by press molding a U-shaped member including a U-shaped cross section. The U-shaped cross section includes at least five curved portions. The curved portions include a center curved portion facing an opening of the U-shaped cross section defined by both edges of the U-shaped cross section; a first right curved portion; a second right curved portion; a first left curved portion; and a second left curved portion. At least the center curved portion, the first right curved portion, and the first left curved portion each have a radius of curvature smaller than a radius of curvature of a corresponding portion of the pipe cross section.

A sensor includes: a tubular needle member that includes a side wall and defines a hollow portion; and a linear detection member located in the hollow portion. The side wall of the needle member includes a thick portion that is thicker than another portion of the side wall in a cross-section of the needle member, and wherein the thick portion protrudes toward the hollow portion.

An apparatus for manufacturing a bracket-integrated double-layer door impact beam is provided. The apparatus includes a lower mold having a lower cavity formed with a base material molded to have a U-shaped cross section and a predetermined length. The base material is seated on the lower cavity. A lower electrode terminal is disposed in the lower mold to contact the base material. An upper mold has an upper cavity therein and is coupled with the lower mold to pressurize both end portions of the U-shaped cross section of the base material inward to form the base material with an O-shaped cross section. An upper electrode terminal is disposed in the upper mold to contact the base material.

A needle member includes: a tubular side wall through which a hollow portion extends in a longitudinal direction. An opening portion connected to the hollow portion extends laterally through the tubular side wall. The tubular side wall comprises a side wall reinforcement portion located at a position opposing the opening portion, wherein the hollow portion is interposed between the opening portion and the side wall reinforcement portion.

A method for manufacturing a ring includes clamping a first region of a metal sheet against a mandrel, and, while the first region of the metal sheet is clamped against the mandrel, bending the metal sheet around the mandrel to join opposite end faces of the metal sheet and form the ring shaped to the mandrel. A system for manufacturing a ring from a metal sheet includes (a) a mandrel having a ring-shaped surface, (b) a clamp facing the ring-shaped surface and configured to clamp a first region of a metal sheet to the mandrel, and (c) a plurality of dies configured to bend the metal sheet around the mandrel, while the clamp clamps the first region to the mandrel, to join opposite end faces of the metal sheet and form a ring shaped to the ring-shaped surface.