Ring rolling methods and apparatus

A method for the solid state forming of a metallic workpiece into a component of selected configuration with apparatus which includes an electrode means for supporting the workpiece, a rotatable pressure applying electrode of a refractory metal or a refractory alloy adapted to engage the workpiece on the side thereof opposite the workpiece supporting electrode means, and means by which said rotatable electrode can be so biased toward said workpiece supporting electrode means as to exert a pressure of a predetermined magnitude on said workpiece, said method comprising the steps of:

• so heating both said workpiece in that region thereof between the pressure applying, rotatable electrode and the workpiece supporting electrode means and that portion of the rotatable electrode adjacent the workpiece that the electrode will not chill the workpiece by connecting the workpiece across an electrical power source through the pressure applying electrode and the workpiece supporting electrode means;
• so regulating the current density through the workpiece being formed and the force exerted on it by the pressure applying electrode as to maintain the temperature of said workpiece below its melting point but sufficiently high to produce in the heated region of the workpiece between the pressure applying electrode and the workpiece supporting electrode means a localized zone in which the workpiece is in a plastic and flowable condition;
• and displacing said workpiece about its axis of symmetry to thereby translate the workpiece relative to said rotatable electrode and cause the zone in which the plastic condition exists to progress along the workpiece.

A method for the solid state forming of a ring-shaped metallic workpiece into a component of selected cross-sectional configuration with apparatus which includes first and second rotatable electrodes of a refractory metal or a refractory alloy engageable with said workpiece and means for so biasing one of said electrodes against said workpiece as to exert a force or pressure of selected magnitude thereon while the workpiece is supported by the other of said electrodes, said method comprising the steps of:

• so heating both said workpiece in that region thereof between the pressure applying, rotatable electrode and the workpiece supporting electrode and that portion of the rotatable electrode adjacent the workpiece that the electrode will not chill the workpiece by connecting the workpiece across an electrical power source through the pressure applying electrode and the workpiece supporting electrode;
• so regulating the current density through the workpiece being formed and the force exerted on it by the pressure applying electrode as to maintain the temperature of said workpiece below its melting point but sufficiently high to produce in the heated region of the workpiece between the pressure applying electrode and the workpiece supporting electrode a localized zone in which the workpiece is in a plastic and flowable condition;
• and displacing said workpiece about its axis of symmetry to translate the workpiece relative to the electrodes and thereby cause said localized zone to proceed along the workpiece.

Apparatus for forming a metallic workpiece into a component of selected cross-sectional configuration, comprising:

• a frame;
• a first, rotatable, pressure applying electrode fabricated of a refractory metal or a refractory alloy;
• a second, rotatable electrode supported from said frame, said second electrode being fabricated of a refractory metal or a refractory alloy;
• means supporting the first electrode from said frame for movement toward and away from the second electrode;
• means operable to so bias said first rotatable electrode toward said second rotatable electrode as to cause said first electrode to exert a pressure of predetermined magnitude on a workpiece disposed between said electrodes;
• means for heating that portion of the workpiece between the first and second electrodes and that portion of the first electrode contiguous to the workpiece and for impeding the flow of heat away from said heated portion of said first electrode to keep said electrode from chilling said workpiece including means for connecting the workpiece across an electrical power source through said first and second electrodes;
• means for so regulating the current density through the workpiece and the pressure exerted on the workpiece by the first electrode as to maintain the temperature of the workpiece below the solidus temperature of the workpiece between the first and second electrodes a localized zone in which the workpiece is in a plastic and flowable condition;
• means for displacing the workpiece relative to said electrodes to thereby cause the zone in which the plastic condition exists to progress along the workpiece;
• and means by virtue of which said electrodes can be shifted relative to the frame of the apparatus, thereby making said apparatus capable of accommodating workpieces of different sizes and/or configurations.

A method for the solid state forming of a metallic workpiece into a component of selected cross-sectional configuration with apparatus which includes first and second rotatable electrodes of a refractory metal or a refractory alloy engageable with said workpiece and means for so biasing one of said electrodes against said workpiece as to exert a force or pressure of selected magnitude thereon while the workpiece is supported by the other of said electrodes, said method comprising the steps of:

• so heating both said workpiece in that region thereof between the pressure applying, rotatable electrode and the workpiece supporting electrode and that portion of the rotatable electrode adjacent the workpiece that the electrode will not chill the workpiece by connecting the workpiece across an electrical power source through the pressure applying electrode and the workpiece supporting electrode;
• so regulating the current density through the workpiece being formed and the force exerted on it by the pressure applying electrode as to maintain the temperature of said workpiece below its melting point but sufficiently high to produce throughout a first portion of the section of said workpiece a localized zone in which the workpiece is in a plastic and flowable condition while maintaining the material in a second, cold zone portion of the section sufficiently cool as to not exceed the yield strength of the material, whereby the material in said last-mentioned portion of the section will function as integral tooling as the metal in said localized zone flows into the configuration wanted in the component being formed;
• and translating said workpiece relative to said pressure applying electrode to cause said localized zone to proceed along said workpiece.