Provided is a high-strength electric resistance welded steel pipe having excellent bendability and which includes a composition containing, on a mass % basis, C: 0.04% to 0.15%, Si: 0.10% to 0.50%, Mn: 1.0% to 2.2%, P: 0.050% or less, S: 0.005% or less, Cr: 0.2% to 1.0%, Ti: 0.005% to 0.030%, and Al: 0.010% to 0.050%, the balance being Fe and unavoidable impurities, and a microstructure including polygonal ferrite with a volume fraction of 70% or more and retained austenite with a volume fraction of 3% to 20%, the balance being at least one selected from martensite, bainite, and pearlite, wherein the polygonal ferrite has an average grain size of 5 m or more and an aspect ratio of 1.40 or less.

Electric resistance welded steel pipes or steel tubes with a tensile property TS of not less than 434 MPa which have electric resistance welded parts exhibiting both excellent HIC resistance and excellent low-temperature toughness, and methods for manufacturing such steel pipes or steel tubes.

A method for manufacturing an electric resistance welded steel tube including: forming a steel tube material into an almost cylindrical open pipe, the steel tube material being a steel sheet wherein Ti and N satisfy (N/14)<(Ti/47.9); forming an electric resistance welded steel tube by bonding ends of the open pipe to each other by induction resistance welding with heat input controlled so that the bond width is 30 to 65 m; heating the electric resistance welded steel tube to a temperature equal to or higher than the Ac.sub.3 transformation temperature; and diameter-reducing rolling the heated electric resistance welded steel tube with rolling reduction expressed by an outer diameter ratio greater than (125/the bond width before diameter-reducing rolling (m))100% such that the bond width is 25 m or less.

An apparatus (10) for joining a predetermined geometrical profile shape from a sheet material (SM) includes a positioning assembly (12) including a base member (14) and a frame (16) that is operable to receive the sheet material (SM), to configure the sheet material in a predetermined orientation and to linearly translate the sheet material along a process direction (20). A Z-bar (22) is configured to guide a first longitudinal edge (FE) and second longitudinal edge (SE) of the sheet material (SM) into adjacent alignment along the process direction (20). A welding and forging assembly (60) welds and then forges a seam between the first longitudinal edge (FE) and the second longitudinal edge (SE) of the associated sheet material (SM).

A high frequency power supply system provides highly regulated power and frequency to a workpiece load where the highly regulated power and frequency can be independent of the workpiece load characteristics by inverter switching control and an inverter output impedance adjusting and frequency control network that can include precision variable reactors with a geometrically-shaped moveable insert core section and a stationary split-bus section with a complementary geometrically-shaped split bus section and split electric terminal bus section where the insert core section can be moved relative to the stationary split-bus section to vary the inductance of the variable reactors.

An apparatus, method and composition for long length tubing includes continuous production of long length seamless aluminum tubing suitable for use as coiled tubing in hydrocarbon wells. A 2XXX aluminum alloy may be used in combination with a continuous casting/extrusion apparatus using aluminum from a melt. Other metals may be used, as well as continuously cast rod from a casting wheel and belt or conform extruder, which is processed to form a hollow and then sized by drawing.

A method of preparing a pipe-section for welding to another pipe-section to form a pipeline comprising a plurality of said pipe-sections, the method comprising at least the steps of: (i) providing a pipe-section having first and second pipe-ends; (ii) defining a first portion L1 of the longitudinal length of the pipe-section from the first pipe-end being in the range 3% to 40% of the overall length of the pipe-section; (iii) defining a second portion L2 of the longitudinal length of the pipe-section from the end of the first portion L1 towards the second pipe-end; (iv) heating at least the first portion L1 to at least a first temperature T1 of at least 500 C. for at least 2 minutes; (v) maintaining a second temperature T2 of the second portion L2 during step (iv) below the first temperature T1. The invention is able to reduce the strain capacity during reel-laying of a pipeline formed from a plurality of pipe sections formed by the invention.