GB873988A - Improvements in or relating to the cold-forming of metal workpieces - Google Patents

Abstract

873,988. Forging; altering physical and molecular structure. APPEL PROCESS Ltd. March 3, 1958 [Jan. 6, 1958], No. 6672/58. Class 83 (4). A method of cold swaging a metal workpiece W comprises applying progressively increasing radial loads thereto to plasticize the metal from the interior to the exterior, then instantly increasing the loads to shape the metal whilst preventing any rearward elongation, and then gradually. and progressively decreasing the loads to elasticize the metal from outside to inside and pre-stress it outside in tension and inside in compression. The swaging is performed by radial dies 11 spring-biased into engagement with the workpiece, Fig. 2 (not shown), and actuated by rollers 17 engaging transverse cam surfaces 16 on rods 14 driven by eccentrics 50. Backing members 18 are supported by adjustable wedges 20 for varying the stroke position. The workpiece which may be of round or hexagonal cross-section, is fed forwardly in steps out-of-phase with the die strokes by means which prevent rearward flow; round workpieces may be rotated. A mandrel 53, Fig. 9 (not shown), which may be toothed is used with hollow workpieces. The method is stated to improve the grain structure and surface of the workpiece and to enable hard steel and molybdenum to be cold swaged. Specific examples are given for swaging hard and mild steel.