Apparatus for forming an explosively expanded tube-tube sheet joint including a low energy transfer cord and booster

Apparatus for expanding a tube into a bore formed in a tube sheet, comprising primary explosive means containing a relatively high number of grains of explosive per unit length and extending within said tube coextensive with that portion of the tube to be expanded;

• an annular force transmitting member extending between said primary explosive means and said tube for transferring to said tube the energy resulting from the explosion of said primary explosive means;
• detonator means disposed externally of said tube;
• an energy transfer cord extending between said detonator means and said primary explosive means, said energy transfer cord including a relatively low number of grains of explosive per unit length which are insufficient to detonate said primary explosive means, and a sheath covering said latter grains of explosive, and being constructed and arranged to contain the debris and gases associated with the explosion of said latter grains of explosive;
• and booster means extending between said energy transfer cord and said primary explosive means, said booster means containing an explosive which is detonatable by said energy transfer cord and, upon exploding, is sufficient to detonate said primary explosive means.