Improvements in and relating to the manufacture of gun tubes, suitable for use in the construction of howitzer and like guns and for the linings of wire-wound and other guns

摘要

142,146. Hadfield, Sir R. A., Jack, A. G. M., and Clerke, A. B. H. March 1, 1918. Ordnance; tubes.-Guns or gun tubes are made from cast billets by piercing, drawing, or turning and boring, and heat-treatment. A tapering grooved billet as described in Specification 4228/15, [Class 83 (i), Casting &c. metals], is cast, the head is cut off, and it is roughly turned to a uniform diameter without removing the grooves completely. After heating, it is inserted in a matrix h, Fig. 19, which it fits. The billet is then pierced and extruded by an hydraulic plunger n while supported by a plug k and ribbed abutment m. After the return of the plunger n and removal of the abutment m, the billet is ejected by an hydraulic pusher p. The heated billet is then reduced in diameter in a number of stages by pushing through single or multiple dies r by mandrels n1, Fig. 21, of smaller diameter than the hole in the billet or tube acted on. To ensure centring, each successive mandrel is blunter than the preceding one, and to avoid driving the mandrel through the end a2, this may be cooled before and during the draw. A stripper is slipped between the last die of a set and the tube end, and, when the mandrel retires, the tube falls into the cradle f. For facilitating the placing of the tube on the mandrel, this may be ball-jointed at t and raised, as shown in Fig. 24, by an hydraulic device u on a carriage w. The first die of a set may merely serve as a guide. After drawing, the tube is roughly turned and bored to the required finished dimensions, and, in the case of a gun lining, the closed end is cut off. The tube is finally hardened and tempered.