A metal pipe having a thickened end portion, the metal pipe includes: when viewed in a longitudinal direction of the metal pipe, a thin portion which has a thickness t.sub.0; a first thickened portion which is provided on one end and has a thickness T which is larger than the thickness t.sub.0; and a first taper portion which is provided between the thin portion and the first thickened portion and has the thickness which gradually increases from t.sub.0 to T; when a hardness of an inner surface of the first thickened portion is measured in a circumferential direction and the hardness is plotted with respect to a position in the circumferential direction, in which a waveform representing a high hardness portion having a hardness which is 95% or more of a maximum hardness in the circumferential direction and a waveform representing a low hardness portion having a hardness which is less than 95% of the maximum hardness alternately appear, and a plurality of combinations of the waveform representing the high hardness portion and the waveform representing the low hardness portion appear.

A metal pipe having a thickened end portion, the metal pipe includes: when viewed in a longitudinal direction of the metal pipe, a thin portion which has a thickness t.sub.0; a first thickened portion which is provided on one end and has a thickness T which is larger than the thickness t.sub.0; and a first taper portion which is provided between the thin portion and the first thickened portion and has the thickness which gradually increases from t.sub.0 to T; when a hardness of an inner surface of the first thickened portion is measured in a circumferential direction and the hardness is plotted with respect to a position in the circumferential direction, in which a waveform representing a high hardness portion having a hardness which is 95% or more of a maximum hardness in the circumferential direction and a waveform representing a low hardness portion having a hardness which is less than 95% of the maximum hardness alternately appear, and a plurality of combinations of the waveform representing the high hardness portion and the waveform representing the low hardness portion appear.

Products and methods for providing structural strength and form support to ventilation pipes.

Products and methods for providing structural strength and form support to ventilation pipes.

A method protects a field joint of a pipeline, where chamfered edges of thermally-insulating parent coatings on conjoined pipe lengths are in mutual opposition about a longitudinally-extending gap. The method includes manufacturing an hourglass-shaped inner layer around the pipe lengths, which layer may be moulded. The inner layer extends longitudinally along the gap between the chamfered edges and at least partially overlies the chamfered edges. A thermally-insulating solid insert is assembled from two or more parts to lie in the gap surrounding the inner layer, and pressure is applied radially inwardly from the insert to the inner layer. An outer layer of molten material is manufactured around the insert to form a watertight barrier and to form one or more melted interfaces with the inner layer. Corresponding field joint arrangements are also disclosed.

A method protects a field joint of a pipeline, where chamfered edges of thermally-insulating parent coatings on conjoined pipe lengths are in mutual opposition about a longitudinally-extending gap. The method includes manufacturing an hourglass-shaped inner layer around the pipe lengths, which layer may be moulded. The inner layer extends longitudinally along the gap between the chamfered edges and at least partially overlies the chamfered edges. A thermally-insulating solid insert is assembled from two or more parts to lie in the gap surrounding the inner layer, and pressure is applied radially inwardly from the insert to the inner layer. An outer layer of molten material is manufactured around the insert to form a watertight barrier and to form one or more melted interfaces with the inner layer. Corresponding field joint arrangements are also disclosed.

A loose lining structure based on a tantalum plate and a steel clad plate is disclosed, which includes a plate cladding base formed by the steel clad plate and the tantalum plate covered on the steel clad plate. The steel clad plate is formed by a steel layer and a cladding layer laid on the steel layer, a periphery of the tantalum plate is fixed with the cladding layer through welding, a medium circulation pipe and/or a reinforcement fastening are/is set on the plate cladding base, the medium circulation pipe includes a tantalum liner tube, the reinforcement fastening is a tantalum plug. Also, a manufacturing method of the loose lining structure based on the tantalum plate and the steel clad plate is disclosed, which includes steps of (S1) fixing through welding; (S2) processing installing holes; and (S3) installing components.

A loose lining structure based on a tantalum plate and a steel clad plate is disclosed, which includes a plate cladding base formed by the steel clad plate and the tantalum plate covered on the steel clad plate. The steel clad plate is formed by a steel layer and a cladding layer laid on the steel layer, a periphery of the tantalum plate is fixed with the cladding layer through welding, a medium circulation pipe and/or a reinforcement fastening are/is set on the plate cladding base, the medium circulation pipe includes a tantalum liner tube, the reinforcement fastening is a tantalum plug. Also, a manufacturing method of the loose lining structure based on the tantalum plate and the steel clad plate is disclosed, which includes steps of (S1) fixing through welding; (S2) processing installing holes; and (S3) installing components.

A method for providing a fluid supply conduit configured to pass through a constrained environment, including providing a circular section tube of appropriate dimensions, die stamping the circular section tube so as to obtain an oblong section tube of oval section, providing a plurality of external stiffeners of hollowed out shape adapted to the external dimensions of the oblong section tube, assembling the external stiffeners around a portion of the section of the oblong section tube.

A method for providing a fluid supply conduit configured to pass through a constrained environment, including providing a circular section tube of appropriate dimensions, die stamping the circular section tube so as to obtain an oblong section tube of oval section, providing a plurality of external stiffeners of hollowed out shape adapted to the external dimensions of the oblong section tube, assembling the external stiffeners around a portion of the section of the oblong section tube.