Titanium stretch forming apparatus and method

A stretch-forming apparatus for forming an elongate metal workpiece, comprising:

• a die having a working face having a predetermined cross-sectional profile adapted to receive and form the workpiece, the die being electrically insulated against passage of electric current from the workpiece to the die;
• a heat-insulating enclosure that includes first and second aligned and opposed workpiece openings in respective first and second spaced-apart sidewalls of the enclosure between which the die is positioned, the openings being structured so that the workpiece ends extend through the openings when the workpiece is positioned within the enclosure in forming proximity to the working face of the die, the enclosure further comprising a sliding panel in each of the first and second spaced-apart sidewalls, the first and second workpiece openings being formed in respective ones of the sliding panels and having a size and shape only just large enough to receive the workpiece therethrough and adapted to move along the sidewalls of the enclosure as the workpiece is formed for reducing heat loss through the workpiece openings;
• first and second opposed swing arms;
• first and second opposed jaws mounted on respective first and second opposed swing arms, each jaw being structured to grip a respective end of the workpiece;
• heating means for electric resistance heating the workpiece to a working temperature;
• and
• movement means for moving the working face of the die and the workpiece relative to each other so as to form the workpiece against the working face of the die into a preselected form.