GB767481A - Improvements in the manufacture of tubular metal elements - Google Patents

Abstract

767,481. Making tubular elements; forging. HUET, A. Sept. 24, 1951 [Sept. 22, 1950; Feb. 19, 1951; Feb. 26, 1951], No. 22277/51. Classes 83 (2) and 83 (4). A method of manufacturing a tubular metal element comprises obtaining a concentric bulb on a tube by axial compression, and then shaping in a semi-cylindrical die so as to render the bulb eccentric without substantially increasing the thickness of the wall of the tube, causing material of the tube wall at the location of the bulb to pass from one sector of the tube towards the opposite sector. An axial swelling b, Fig. 1, is formed on a tube a, e.g. by upsetting in an electrical upsetting-machine and the swelling displaced to form the eccentric bulb b<SP>1</SP> by forging with internal mandrel C, the bulb being completely or partially heated. The bulb may then be opened, Fig. 4, to form a connection for a pipe whose diameter D may be greater than the diameter d of the tube a. The tube may be bent, Fig. 8, and the bulb b1 may be pressed back to provide a bend with a thick external wall, Fig. 9. In a modification, Figs. 11 and 12, the axial bulb is displaced in a die to form an internal projection p in the tube, and opened to form a connection f. The eccentricity of the bulb may be accentuated by axial electrical upsetting before opening. In a further modification. Fig. 17, a punch k is introduced into the connection f and the tube axially upset to size the connection I around the punch. Angular bending. The tube may be bent around a former g, Fig. 6, axially reciprocable by a jack g3, by sweep-arms comprising rollers hl, h2 and connecting rods j1, j2, k1 k2, operated by a piston m. The tube is held on the former by a stirrup o and initially bent by movement of the former. In a modification the former is fixed and the rollers h1, h2 are slidably mounted to enable the initial bend, Fig. 6, to be achieved. Specification 663,427 is referred to.