GB514379A - Improvements in and relating to producing hollow bodies - Google Patents

Abstract

514,379. Making hollow-ware. DEBOR, H., and DEBOR, R. March 31, 1938, Nos. 9908 and 9909. Convention dates, April 1, 1937, and Feb. 28, 1938. [Classes 83 (ii) and 83 (iv)] Forging; stumping. - Hollow metal bodies curved in more than one direction are made from bodies curved in one direction only by electrically heating until plastic enough to upset and then simultaneously applying relatively regulated axial and internal elastic pressures to obtain one or more expanded portions of any desired thickness which may be equal to or greater than the original thickness. The body may be expanded into a divided die which is closed before or during the process. The body may be subjected to a heat treatment. The Specification as open to inspection under Sect. 91 comprises examples of bodies which may be used-as'pressure gas containers and of apparatus, for carrying out the process. Fig. 8 (Cancelled) shows a tube 38 gripped by clamps 43 heated between electrodes 41 and 42 and supplied with internal gas presure through a pipe 39 and compressed axially by the piston rod of an oil pressure cylinder 35, the swelling so formed taking the shape of the dies 31, 32 mounted on and moving together with the clamps. A transformer 44 supplies secondary heating current to the tube through the electrodes 41, 42 the dies being insulated by layers 40 from the electrodes. A step switch 46 regulates the current. Heat treatment may be applied while the expanded body is still surrounded by the dies. In another apparatus for making multiple swellings, Fig. 9 (Cancelled), the dies are in top and bottom halves, clamped together, and are moved together axially by a lazy tongs 55. A guide bar 57 keeps them aligned. This subject-matter does not appear in the Specification as accepted.