Method of thickening the wall of a tube

Claim 1

THE METHOD OF COLD THICKENING AN AXIAL ZONE OF A TUBULAR METAL WORKPIECE WHICH INCLUDES TAKING A NOMINALLY CIRCULAR TUBE HAVING A LONGITUDINALLY EXTENDING GRAIN, WHICH TUBE MAY VARY SLIGHTLY FROM PRECISE CIRCULAR SHAPE AND HAS A NOMINALLY UNIFORM OUTSIDE DIAMETER, WHICH DIAMETER MAY VARY SLIGHTLY ALONG THE LENGTH OF THE TUBE, PRESSING THE TUBE AXIALLY INGO A CYLINDRICAL DIE HAVING IN SAID ZONE A UNIFORM INTERNAL DIAMETER SLIGHTLY LESS THAN THE MINIMUM OUTSIDE DIAMETER OF THE TUBE TO FORM THE PORTION OF TUBE IN THE ZONE IN TO A PRECISELY CIRCULAR SHAPE OF UNIFORM OUTSIDE DIAMETER, WHICH PORTION IN THE ZONE IS UNIFORMALY RIGIDLY SUPPORTED RADIALLY BY INTIMATE CONTACT WITH THE DIE AS A RESULT OF THE FORMING OPERATION, USING AN INTERNAL FORM IN SAID ZONE OF THE TUBE, AND APPLYING TO THE TUBE AT OPPOSITE ENDS OF SAID ZONE AXIALLY COMPRESSIVE FORCE TO SHORTEN THE TUBE AND CAUSE THE COLD METAL TO FLOW AN CONFORM ACCURATELY TO THE INTERNAL FORM WITHOUT FOLDNG OR BENDING TO MAKE A WORKPIECE HAVING A THICK WALLED ANNULAR PORTION AND AN AXIALLY ADJACENT THIN WALLED ANNULAR PORTION IN WHICH WORKPIECE THE GRAIN OF THE METAL REMAINS GENERALLY STRAIGH AND PARALLEL TO THE AXIS THROUGHOUT THE LENGTH OF THE WORKPIECE AND EXPANDS SMOOTHLY AND CONTINUOUSLY FROM THE THIN WALLED PORTION INTO THE THICK WALLED PORTION.

Claim 2

THE METHOD OF COLD THICKENING AN AXIAL ZONE OF A TUBULAR METAL WORKPIECE WHICH INCLUDES TAKING A NOMINALLY CIRCULAR TUBE HAVING A LONGITUDINALLY EXTENDING GRAIN, WHICH TUBE MAY VARY SLIGHTLY FROM PRECISE CIRCULAR SHAPE AND HAS A NOMINALLY UNIFORM OUTSIDE DIAMETER, WHICH DIAMETER MAY VARY SLIGHTLY ALONG THE LENGTH OF THE TUBE, PRESSING THE TUBE AXIALLY INGO A CYLINDRICAL DIE HAVING IN SAID ZONE A UNIFORM INTERNAL DIAMETER SLIGHTLY LESS THAN THE MINIMUM OUTSIDE DIAMETER OF THE TUBE TO FORM THE PORTION OF TUBE IN THE ZONE IN TO A PRECISELY CIRCULAR SHAPE OF UNIFORM OUTSIDE DIAMETER, WHICH PORTION IN THE ZONE IS UNIFORMALY RIGIDLY SUPPORTED RADIALLY BY INTIMATE CONTACT WITH THE DIE AS A RESULT OF THE FORMING OPERATION, USING AN INTERNAL FORM IN SAID ZONE OF THE TUBE, AND APPLYING TO THE TUBE AT OPPOSITE ENDS OF SAID ZONE AXIALLY COMPRESSIVE FORCE TO SHORTEN THE TUBE AND CAUSE THE COLD METAL TO FLOW AN CONFORM ACCURATELY TO THE INTERNAL FORM WITHOUT FOLDNG OR BENDING TO MAKE A WORKPIECE HAVING A THICK WALLED ANNULAR PORTION AND AN AXIALLY ADJACENT THIN WALLED ANNULAR PORTION IN WHICH WORKPIECE THE GRAIN OF THE METAL REMAINS GENERALLY STRAIGH AND PARALLEL TO THE AXIS THROUGHOUT THE LENGTH OF THE WORKPIECE AND EXPANDS SMOOTHLY AND CONTINUOUSLY FROM THE THIN WALLED PORTION INTO THE THICK WALLED PORTION.