Explosive jointing may be effected by explosive welding or by some type of shrink joint. As a rule, explosive jointing of large-diameter pipes such as pipelines is effected using interiorly placed annular charges which act against an exteriorly placed support or abutment. In order to provide a completely satisfactory joint, the charges must abut quite closely to the inner surface of the pipe. Minor deviations from circular configuration in the pipe may, in such operations, be compensated for in that the charge is made elastically deformable. However, the requirement of a special charge diameter for each pipe diameter remains, as well as the requirement of a good connection between the outside of the charge and the inner surface of the pipe. Moreover, the fact that the charge may not be so elastically deformable that it fails to be self-supporting may result in the situation that standard charges cannot always be used in such pipes whose dimensional tolerances lie at the extreme margins of accepted tolerance ranges for the pipe in question. Of necessity, the dimensional tolerances for such large-diameter pipes as pipelines are quite broad. Hence, a plurality of different charge dimensions for one and the same type of pipe may be necessary, and this, of course, increases costs.
The standard method within the prior art for producing such annular charges intended for explosion welding has been to cast the charges. This is quite a circumstantial procedure if the intention is to produce a plurality of charges of different, but relatively similar, accurately specified outer diameters.
USPTO Backgrounds
USPTO Backgrounds