US Patent 7305860 Method for tube forming

A method is provided for forming a tube between a pair of dies. The tube is captured between a pair of dies having die surfaces constructed of an electrically non-conducting material defining a die cavity therein. The ends of the tube are sealed and electrical current is applied to the tube to induce electrical resistance heating of the tube. The interior of the tube is pressurized to expand the tube into the cavity to thereby form the heated tube.