Abstract: A coaxial pipe element (1) includes an outer pipe (1a) and an inner pipe (1b), and at each of its ends a junction forging (2a, 2b), each forging having at least an inner first branch (32) set back (L1) from an outer first branch (31), in which all of the circular welds between the inner and the outer pipe and the junction forgings are made on the outside of the pipes.

Abstract: A peening device suitable for peening annular weld zones inside undersea pipes, the device comprising at least one peening tool, with at least one hammer actuated to perform radial reciprocating movement in translation for peening against the inside surface of the pipe and/or said weld, wherein: said peening tool has a single hammer; and said hammer is pivotally mounted so as to be capable of varying its angle of inclination relative to the surface for peening; and said device includes a carriage suitable for moving in axial longitudinal translation XX inside a pipe and for supporting means for moving said peening tool in longitudinal and radial translation, and in rotation relative to said carriage; and said hammer co-operates with means for actuating radial reciprocating movements in translation by peening by making use of electromagnetic energy and reciprocating motion inside a solenoid coil, preferably also in co-operation with a spring.

Abstract: The present invention relates to a coaxial pipe element comprising an inner pipe and an outer pipe and having at each of its ends a closure of the annular space between these two pipes, in particular by means of a forging, and in which said inner pipe is subjected to traction stress.

Abstract: The present invention relates to a method of fabricating a coaxial pipe element (1) comprising an outer pipe (1a) and an inner pipe (1b), and including at each of its ends a junction forging (2a, 2b), each forging having at least an inner first branch (32) set back (L1) from an outer first branch (31), in which all of the circular welds between said inner and outer pipe and said junction forgings are made form outside said pipes. The present invention also provides a coaxial pipe element (1) obtained by the method and characterized in that said inner pipe (1b) is subjected to traction stress.