EXPLOSIVE WELDING OF TUBING

摘要

1445486 Welding by pressure and fusion EXPLOSIVE METAL WORKING HOLLAND BV 7 June 1974 [8 June 1973] 25466/74 Heading B3R In welding metal tubes 8, 11 end to end, the end of one tube 8 is bevelled 10 from its outer surface and is bevelled from its inner surface, the end of the other tube 11 is bevelled 13 from its outer surface and is provided with a frustoconical projection 12 at its inner surface, the projection 12 is fitted within the bevel 9 from the inner surface of the one tube, an explosive charge 15 is detonated within the tubes to weld the projection to the bevel 9 and the cavity 20 formed by the bevels 10, 13 on the tubes is filled by fusion welding 23. The pipes, in an embodiment form part of a pipe line and the explosive charge 15 is annular and supported on a member 14, a supporting block 19 retaining the tubes during the explosive detonation. The tubes are explosively welded at 22 and then the block 19 is removed and the circumferential groove 20 is filled up with weld material 23 using an electric arc or a torch. In another embodiment two tubes having internal cladding are similarly welded, the internal cladding forming part of the inner bevel on the one tube and part of the projection on the other. It is preferred to produce a small groove in each tube end to space the internal cladding from the tube. A prior art method of joining two internally clad tubes is described in which the cladding layers project beyond the non-bevelled tube ends, and are electrically or torch welded. Each cladding layer is welded to its tube, a layer of cladding material is welded over the projecting cladding layers and finally the space between the tube ends is filled with weld metal. Passages passing from the exterior through the tubes to the cladding layers are provided to relieve the joints between the cladding layers and the tubes of pressure.