Alcan Research and Development Limited

William James Kirkpatrick

Wayne Richard Wilson

The invention relates to a method of joining together the ends of tubular metal members by explosive welding and to a permanent, self-aligning backing mandrel for use in the method. The mandrel is in the form of a tubular member having an outer face defining a cylindrical portion and an axially adjacent tapered portion, the maximum diameter of the tapered portion being greater than the diameter of the cylindrical portion. An annular shoulder extends outwardly between the cylindrical portion and the maximum diameter end of the tapered portion, which tapers inwardly away from the shoulder. One pipe end is outwardly flared and fits over the tapered portion of the mandrel and the other pipe end is non-flared and fits over the cylindrical portion, abutting the shoulder. The outer end of the flared pipe end overlaps the non-flared pipe, defining therewith an annular wedge-shaped outwardly-opening space. An explosive is located around this outer overlapping end and is detonated to weld the ends together.

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Kingston, Canada

William James Kirkpatrick