Electric resistance welded steel pipe securing the high strength and high toughness demanded from oil well pipe in recent years. The metal structure in a region having a width of 0.5 mm in both the thickness directions from a reference point, when using a point defined as a point of the thickness in the thickness direction from the surface in the base material part of the steel as the reference point, consists of polygonal ferrite: 10 area % or less and a balance: bainitic ferrite. The thickness is 15 mm or more.

Embodiments provide a helical layer structure including: a helical core member which is formed of a flexible, lengthy, flat plate-like core member and which is formed of a steel plate made of a metal material, such as iron; and a polymeric coating layer which is formed of a polymeric material such as a thermosetting elastic material or a thermoplastic elastic material, and which coats the helical core member. The manufacturing method of the helical layer structure includes: a feeding step of feeding a core member having flexibility; a supply step of supplying the polymeric material having fluidity; a coating step of coating the core member with the polymeric material; a cooling step of cooling a coated intermediate which is coated with the polymeric material; and a helix formation step of helically twisting the coated intermediate to form the helical layer structure.

The present invention discloses a metal strip winding continuous reinforced thermoplastic composite pipe. The present invention adopts a method designed for grouping the winding metal strips to rationally distribute the winding mode of the metal strips, and at the same time, increases the hoop strength and axial strength of the pipe by using the feature of high strength of the metal strips, thereby improving the compressive capacity of the pipe; there is no bonding between the metal strip reinforcement layers, which improves the flexibility of the composite pipe and reduces the relative slippage between the metal strip layers; the production process is simple, and requirements for the equipment investment are small, thereby greatly reducing the manufacturing cost and ensuring the flexibility and seismic resistance of the pipeline.

Mining methods and systems are disclosed for In-Situ Leaching (ISL) of the mineral ores. ISL extraction is conducted by injecting a suitable leach solution into the ore zone below the water table; oxidizing, complexing and mobilizing the minerals; recovering the pregnant (loaded) solutions through production wells (extraction wells or recovery wells); and, finally, pumping the minerals bearing solution to the surface for further processing. In these methods strips of fabrics saturated with resin are helically or non-helically wrapped around desired shape vertical mandrels, located over the wells, and the partially cured pipes are lowered into the wells to line the wells. These onsite manufactured pipes/linings are used to pump chemical solutions into the ores and subsequently to recover the pregnant (loaded) solutions.

A flanged ring connector (50) for connecting adjacent ends of HVAC ducting (52) includes an insertion flange portion to engage within the interior of the ducting. A mating flange portion (56) extends laterally or transversely to the insertion flange portion (54). A seat (58) is formed along the mating flange portion (56) to receive and retain a seal (60) and/or a reinforcing member or bead (90).

A flanged ring connector (50) for connecting adjacent ends of HVAC ducting (52) includes an insertion flange portion to engage within the interior of the ducting. A mating flange portion (56) extends laterally or transversely to the insertion flange portion (54). A seat (58) is formed along the mating flange portion (56) to receive and retain a seal (60) and/or a reinforcing member or bead (90).

Mining methods and systems are disclosed for In-Situ Leaching (ISL) of the mineral ores. ISL extraction is conducted by injecting a suitable leach solution into the ore zone below the water table; oxidizing, complexing and mobilizing the minerals; recovering the pregnant (loaded) solutions through production wells (extraction wells or recovery wells); and, finally, pumping the minerals bearing solution to the surface for further processing. In these methods strips of fabrics saturated with resin are helically or non-helically wrapped around desired shape vertical mandrels, located over the wells, and the partially cured pipes are lowered into the wells to line the wells. These onsite manufactured pipes/linings are used to pump chemical solutions into the ores and subsequently to recover the pregnant (loaded) solutions.

A method for manufacturing an electric resistance welded steel pipe having an identifiable seam portion. The method includes electric resistance welding a steel pipe, cutting an inner surface bead and an outer surface bead of the steel pipe in such a manner so as to cut: (i) a whole the outer surface bead and a part of the inner surface bead to leave an uncut portion in the inner surface bead, or (ii) a whole of the inner surface bead and a part of the outer surface bead to leave an uncut portion in the outer surface bead, coating the steel pipe with zinc phosphate, and cold drawing the steel pipe using a plug and a die to make the seam portion of the steel pipe identifiable.

An electric resistance welded steel pipe having an identifiable seam portion and a method for manufacturing the same. The electric resistance welded steel pipe includes a steel pipe portion with a seam portion, which is formed by electric resistance welding, and a coating portion of zinc phosphate. The coating portion covers at least an outer surface side of the steel pipe portion. A part of the coating portion that is immediately above the seam portion forms a color difference portion that has a width W along a pipe circumferential direction of greater than or equal to 0.1 times a wall thickness of the pipe and less than or equal to the wall thickness of the pipe. The color difference portion has a visually identifiable color difference from the other parts of the coating portion.

An electric-resistance-welded stainless clad steel pipe or tube that is excellent in both the fracture property of the weld and the corrosion resistance of the pipe or tube inner surface as electric resistance welded without additional welding treatment such as weld overlaying after electric resistance welding is provided. An electric-resistance-welded stainless clad steel pipe or tube comprises: an outer layer of carbon steel or low-alloy steel; and an inner layer of austenitic stainless steel having a predetermined chemical composition, wherein a flatness value h/D in a 90 flattening test in accordance with JIS G 3445 is less than 0.3, and a pipe or tube inner surface has no crack in a sulfuric acid-copper sulfate corrosion test in accordance with ASTM A262-13, Practice E, where h is a flattening crack height (mm), and D is a pipe or tube outer diameter (mm).