A method for manufacturing a clad steel pipe is provided, wherein the clad steel pipe is manufactured by using a clad steel plate as a raw material. The clad steel plate comprises a base layer (1) and a clad layer (2) roll-bonded with the base layer (1). The method for manufacturing a clad steel pipe comprises the steps of forming, welding, and deburring; both sides of the clad steel plate are bent towards the base layer (1) side of the clad steel plate, then the forming step is carried out, and after the forming step, the opening faces of the resultant pipe blank are all in a form of the clad layer (2). According to the method for manufacturing a clad steel pipe, a clad steel pipe is manufactured by using a clad steel plate as a raw material. Thus, continuance and high efficiency of a high-frequency longitudinal welding pipe unit is fully utilized, subsequent non-continuous processes are not necessary, and the corrosion resistance at the weld of the clad steel pipe is ensured.

A vehicle door beam and related methods of making door beams include a flat-rolled aluminum alloy sheet, where two edges of the sheet that are transverse to the roll direction of the sheet are brought together to form a tube. The two edges are friction stir welded together to form a butt joint along a length of the tube. The tube is arranged, along with other optional components, as a side-impact door beam in a vehicle door, such that the butt joint is facing away from an expected impact direction of the vehicle door.

Tube forming methods can be used for efficient transition in the production of tubes having varying thickness. Material used to form consecutive tubes may have the same thickness along a separation plane separating a first discrete section from a second discrete section of the material, and the first discrete section and the second discrete section may each have varying thickness in a feed direction of the material. With such a thickness profile, the first discrete section of the material may be formed into a first cylinder having varying thickness and separated from the second discrete portion as the second discrete section is formed into a second cylinder having varying thickness. In particular, the transition between the first cylinder and the second cylinder may be achieved without scrap and/or interruption, resulting in cost-savings and improvements in production throughput associated with forming tubes having varying thickness.

The present invention relates to steel used for a sash component and the like of a vehicle and, more specifically, to a hot-rolled steel sheet for a high-strength electric resistance welded steel pipe having excellent expandability and a method for manufacturing same, the hot-rolled steel sheet having a smaller decrease in the strength of a welding heat-affected zone (HAZ) formed during electric resistance welding, in comparison with a base material.

Spiral forming devices, systems, and methods can be used to join edges of a of a stock material, in a curved configuration, along one or more joints to form tubular structures, such as conical and/or cylindrical structures (e.g., frusto-conical structures). A planar form of the stock material can be formed from a plurality planar sheets coupled to one another in an abutting relationship. By controlling relative orientation and shapes of the plurality of planar sheets forming the stock material and/or by controlling a position of a roll bender used to curve the planar form of the stock material into the curved configuration, the curved configuration of the stock material can be controlled through transitions between sheets to facilitate rolling the sheets to a desired diameter with a reduced likelihood of dimples or other errors and to facilitate fit up between adjacent sheets in the curved configuration.

Provided are a hot-rolled steel sheet for an electric resistance welded steel pipe and a method for manufacturing the same, an electric resistance welded steel pipe and a method for manufacturing the same, a line pipe, and a building structure. The hot-rolled steel sheet has a chemical composition containing, by mass %, C: 0.030% or more and 0.20% or less, Si: 0.02% or more and 1.0% or less, Mn: 0.40% or more and 3.0% or less, P: 0.050% or less, S: 0.020% or less, N: 0.0070% or more and 0.10% or less, and Al: 0.005% or more and 0.080% or less, the balance being Fe and incidental impurities, in which N dissolved in steel is contained in an amount of 0.0010% or more and 0.090% or less, and letting a sheet thickness be t, a steel microstructure at a ½t position has an average grain size of 20.0 μm or less.

Provided is an electric resistance welded steel pipe or tube having excellent fatigue durability after rapid and short-time heating quenching treatment. An electric resistance welded steel pipe or tube comprises: a base metal being a steel sheet having a specific chemical composition and an electric resistance weld portion having a bond width of 40×10.sup.−6 m or more and 120×10.sup.−6 m or less, wherein C.sub.0-C.sub.1 is 0.05 mass % or less, where C.sub.0-C.sub.1 is a difference between C.sub.1 in mass % which is a minimum C content of the electric resistance weld portion and C.sub.0 in mass % which is a C content of the steel sheet, and a depth of a total decarburized layer in each of an inner surface layer and an outer surface layer of the electric resistance welded steel pipe or tube is 50×10.sup.−6 m or less.

A double-wall spiral welded pipe includes a first steel belt layer and a second steel belt layer which have equal widths, are arranged in parallel and align with each other; at least two supporting steel bars perpendicular to the first steel belt layer and the second steel belt layer are arranged between the first steel belt layer and the second steel belt layer; the supporting steel bars are arranged on end parts of two sides of the first steel belt layer and the second steel belt layer and extend together with the first steel belt layer and the second steel belt layer; and the first steel belt layer, the second steel belt layer and the supporting steel bars on the end parts of the two sides are mutually welded to form a double-layer composite steel belt with a rectangular section in an extending direction.

The invention provides a pneumatic conveying system having a series of supply lines with at least portions of the lines being wear resistant to extend the useful lifespan of an agricultural product delivery applicator. The wear resistant supply line(s) may be made from a hard material and have a curve(s) defined by angled or mitered segments that are welded or otherwise joined to collectively provide the curve(s) The wear resistant supply lines may be at least partially reinforced by way of, for example, welded or other build up wear resistant material(s) at high wear zones of the supply lines.

A refrigerant pipe constituting a refrigerant circuit of a refrigeration apparatus, includes: a pipe body made of stainless steel; and a first connecting tube made of copper or a copper alloy and that is configured to connect a first different refrigerant pipe to the refrigerant pipe. The first connecting tube is connected to an outer circumferential surface of a first end of the pipe body in a pipe axis direction of the pipe body. The first connecting tube overlaps with the pipe body in a pipe diameter direction in an entirety of the first connecting tube in the pipe axis direction.