a tubular part having a tubular main body and an integral tubular protrusion projecting laterally from the side of the main body and in fluid - tight communication therewith is superplastically formed by inserting the tube in a cavity of a die base and heating the die to a temperature at which the material of which the tube is made exhibits superplastic properties . the distal end of a pull - rod is extended through an opening in the die base and through a hole in the side wall aligned with the opening . a pull - die is selected having a cross section larger than the hole and about equal to the desired internal cross section of the tubular protrusion . the pull die is attached to the distal end of the rod and is heated to about the superplastic temperature of the tubing material . linear actuators are operated to pull the rod and attached pull die through the hole at a predetermined rate which produces about an optimal superplastic strain rate for the material , thereby superplastically stretching marginal portions of the tubular body around the hole and forming the tubing material in marginal regions around the hole against surfaces defining the opening in the die base into the tubular protrusion integrally joined to the tube around an integral junction region .