A process for manufacturing a high nitrogen stainless steel pipe material includes keeping an outside surface and/or an inside surface of an austenite stainless steel pipe material in contact with a substance that becomes a nitrogen (N) source, heating the steel pipe together with the nitrogen source substance at a temperature of 800° C. to 1100° C. in a range of temperatures not higher than the critical temperature for crystal grain enlargement of the steel pipe material to cause nitrogen to be absorbed into the surface of the pipe and diffused into the steel solid phase, and applying to the heat-treated pipe material annealing treatment in the range of temperatures in vacuum, inert gas including argon gas or an atmosphere of a gas with a reducing substance including H.sub.2 gas added thereto, to result in a decrease of nitrogen concentration gradient.

The present disclosure relates to a tube structure comprising an inner tube of metal and an outer tube of metal, wherein the inner tube extends in the outer tube, and wherein either the inner tube and the outer tube are mechanically tight fitted over the entire length of the inner tube, at least one space in a radial direction of the tube structure in the form of a groove extends at least in an outer surface of the inner tube or in an inner surface of the outer tube, and the at least one space extends in a longitudinal direction of the inner tube and over an entire longitudinal extension of the inner tube, or a spacer tube is located between the inner tube and the outer tube, the inner tube, the outer tube and the spacer tube are mechanically tight fitted over the entire length of the spacer tube, the spacer tube comprises at least one space in the form a slit extending in a radial direction of the tube structure from an outer surface of the inner tube to an inner surface of the outer tube, the at least one space extends in a longitudinal direction of the spacer tube and over an entire longitudinal extension of the spacer tube, and wherein the at least one space is at least partially filled with a thermal interface material providing a thermal contact between the outer tube and the inner tube.

The invention relates to a long tubular pipe comprising an outer tube, an inner fluid-transporting tube mounted in the outer tube, and a separating member designed to transmit bending efforts between said outer tube and said inner tube when said outer tube is bent, the separating member comprising means for the longitudinal passage of fluid between the inner tube and the outer tube, the separating member comprising a first edge and a second edge together defining an assembly slot, the first edge and the second edge respectively comprising a first connecting element and a second connecting element designed to cooperate mechanically on the outer periphery of the inner tube.

The present disclosure relates to a bimetallic tube comprising a first metallic tube having an inner diameter and an outer diameter, and a second metallic tube having an inner diameter and an outer diameter, wherein the first metallic tube is arranged within and force-fitted to the second metallic tube and wherein the first metallic tube comprises a zirconium (Zr) based alloy and wherein the second metallic tube comprises an austenitic stainless steel. The present disclosure also relates to a method for manufacturing a bimetallic tube comprising the steps of providing a first metallic tube having an inner diameter and an outer diameter, providing a second metallic tube having an inner diameter and an outer diameter, wherein the outer diameter of the first metallic tube is smaller than the inner diameter of the second tube, insetting the first metallic tube into the second metallic tube, cold-drawing the first and second metallic tubes together, such that the first and second metallic tubes are force-fitted together.

An automotive component manufacturing method includes a molding process of pressing a portion of a hollow tube formed from a metal material, or a composite material including a metal and a resin, so as to deform the portion of the hollow tube, from a tube outer side toward a tube inner side, to beyond an axial center of the hollow tube, and mold the portion of the hollow tube into a deformed section deformed with a concave profile; and a deformation process of deforming a location having a high level of residual stress in a closed cross-section configured by the deformed section so as to deform the location out-of-plane.

An automotive component manufacturing method includes a molding process of pressing a portion of a hollow tube formed from a metal material, or a composite material including a metal and a resin, so as to deform the portion of the hollow tube, from a tube outer side toward a tube inner side, to beyond an axial center of the hollow tube, and mold the portion of the hollow tube into a deformed section deformed with a concave profile; and a deformation process of deforming a location having a high level of residual stress in a closed cross-section configured by the deformed section so as to deform the location out-of-plane.

A method to make a tubular element to transfer abrasive materials such as concrete, inert materials or suchlike, where the tubular element includes an external tubular component made of steel and an internal tubular component, coaxial to the external tubular component, where the internal tubular component is made of chromium carbide, or other similar material resistant to wear.

The invention relates to a process for producing a multilayer pipe (1) from a tubular element having a metallurgical bond comprising at least one outer pipe (10) of metallic material and one inner pipe (20) of metallic material arranged within the outer pipe, the inner surface of the outer pipe (10) being mechanically bonded to the outer surface of the inner pipe (20) at least in parts of their interface, in which, in a production line, the tubular element is simultaneously heated and drawn, wherein each portion of the tubular element is submitted to heating by induction and then to hot-drawing, wherein the tubular element is drawn with a mandrel located therein. Through this process, the existing mechanical connection between the pipes is trans-formed in a metallurgical connection. The invention also relates to a multilayer pipe (1) produced for this process, wherein the outer pipe (10) is made of a carbon manganese steel alloy and the inner pipe (2) is made of a corrosion-resistant alloy.

A method of making an annular component includes forming sheet feedstock into an annular shape disposed about a central axis; and bonding one portion of the feedstock to another portion of the feedstock using ultrasonic welding, so as to fix the annular shape.

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.