Explosion-welding of external fins and ledges on tubes - where explosive detonated in bore forces tube onto fins held in prestressed housing

摘要

This technique can be used to join materials not normally regarded as weldable, e.g. components for aero and space applications. To join e.g. four longitudinal fins at intervals of 90 degrees round a tube, four heavy segments are used to form a cylinder and sections are cut out in the bore, at the joint faces, (i.e. at 90 degrees) so that the profiles mate with the profiles of the fins (the profiles of the fins can vary, the only requirement being that their cross-section is matched by cut-outs). In this way, the fins are supported by the cylinder along their entire length. Two half-shells are mounted outside the segments with belts so that the segments are pre-stressed. The tube to be welded to the fins is placed inside the cylinder, and a uniform layer of explosive on the bore of the tube is detonated so that the tube wall is forced onto the fins. The bore of the cylindrical segments is coated with an inhibitor to prevent welding occurring except at the desired points. Spiral fins can be produced by this method.