Compagnie Francaise Des Petroles

Claude R Carsac

Bruno J De Sivry

Jean-Pierre Hamon

Christian Bonnet

Bernard G Sudreau

Michel Fuzeau

The characteristics of a weld made by electron beam welding are improved by introducing into the region of the pieces to be welded, which is subjected to remelting during welding, a material which is obtained by applying an arc welding process, or a process for remelting under slag, to a mild or slightly alloyed steel. The introduction of the material into the region of the weld increases the production of acicular ferrite which increases the tensile strength of the weld. The material may be introduced by providing a deposit of it over part or the whole of the surface of one or both of the pieces to be welded, by introducing a mass of it between the surfaces to be welded or as a filler wire.

Electron beam welding

An electron beam welding chamber for butt joining elongate members 1,2 extending longitudinally at the center of the chamber. The chamber comprises an envelope 7 defining the welding enclosure 6 and which rests on a fixed structure 8. The electron gun equipment 13 is provided within the envelope and is mechanically connected, by a withdrawable connection means 18 or by elastic connection means 24, 25, to the enclosure, clamping means 15 being provided for clamping the electron gun equipment relative to one of the elongate members. This invention is particularly applicable to the welding of the sections of a pipe to be laid on the sea bed.

Electron beam chamber for butt welding pipes

A welding chamber in which a vacuum is created for welding, using an electron beam, elongate pieces extending centrally of the chamber. The welding chamber is divided into a central sub-enclosure 41 for receiving the pieces 1, 2 to be welded and which is evacuated during welding, and a peripheral sub-enclosure 42 in which the welding means are located and which is permanently evacuated, the two sub-enclosures being separated by retractable sealing gaskets 12, 26, 27 which are retracted during welding to place the two sub-enclosures in communication.

Vacuum chamber for electron beam butt welding of pipes

In a process for electron beam welding, the electron beam welding gun is controlled to maintain the power absorbed by the pieces being welded substantially constant. In a preferred embodiment the intensity of the electron beam transmitted by the pieces being welded, which corresponds to the power absorbed, is measured, compared with a preset intensity and the difference used to control the focussing current supplied to the gun to maintain the intensity of the transmitted beam constant.

Electron beam welding with beam focus controlled responsive to absorbed

In the positioning of an assembly of work tools which are required to operate in the plane of the end face of a tubular structure, which is not necessarily orthogonal to the axis of the structure, a theoretical end face is determined by three sensing arms spaced apart by 120.degree., which, by an axial translatory movement followed by two pivotal movements about axes parallel to lines joining pairs of the arms, is brought into coincidence with the actual end face of the structure, then the plane of operation of the tools is brought into coincidence with the plane of coincidence of the theoretical and actual end faces. The work tools may for example be electron beam welding guns for welding an additional tubular element to an existing tubular structure.

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St. Leu la Foret, France

Claude R Carsac