Patent GB-906841-A (GB)
IPC: B21C37/14
Abstract: 906,841. Making laminate strip; making tubes and cans; rolling. CONTINENTAL CAN CO. Inc. May 17, 1960 [Aug. 26, 1959], No. 17378/60. Classes 83 (1), 83 (2) and 83 (4). A method of making laminate strip material, used, upon opening out, in the production of tubes and can bodies, comprises preparing a hollow core of oblong cross-section and of a metal weldable with the metal for forming the major portions of the body structure, mounting the core in a mould and casting said major body metal around the core for welding union therewith and thereby forming an ingot having a hollow channel therein, providing a weld-resistant material in the channel of the ingot, and rolling the ingot to provide a strip having metal laminations of said major body metal separated by the residue of the weld-resisting material, with the laminations connected at the edges of the weld-resisting residue by metal portions extending from external surface to external surface of the strip. Casting.-Four hollow metal cores 21 of, for example, aluminium or aluminium alloy, with their edges coated with a weld-resisting material 89, Fig. 16, are held with their edges abutting by a platform 17 which closes the lower end of a cooled mould 10. An ingot 101 is cast around the cores 21 as they are lowered by piston means 19, rolls 25 and 30 guiding the cores 21, the rolls 25 being braked by means 26 to hold the cores 21 straight. Cooling of the ingot may be assisted by water sprays from nozzles 41. Projections 109 in the mould 10 may form longitudinal grooves in the ingot 101. Making hollow cores; extruding; straightening.-A core 54, Fig. 5, may be made by extrusion through a head 53 over a mandrel 55. Alternatively, round tubing may be rolled to dumb-bell section 61, Fig. 7, on stainless steel strips 62, and then rolled on thinner wider strips to the shape 65, Fig. 9. Again, circular sectioned tubing may be drawn through successive dies to a flattened shape. The cores 54 may be straightened by the tension of clamps 77, Fig. 11, urged apart, the clamps having tongues 78 entering the tube ends. A sizing tool 80, Fig. 13, comprising steel strips with toothed edges to form a broach or a burnishing head, may be pulled through the core 54. The edges of the core 54 are trimmed by milling cutters 85, 86, Fig. 14, the core being held by fingers 87. The weld resisting material 89, Fig. 16, is then applied to the edges. The ingot 101 is scalped by milling cutters 105, Fig. 17, to remove surface irregularities and to shape the ingot and milling cutters 106, Fig. 18, dress the longitudinal grooves in the ingot formed by the projections 109 in the mould 10 or by die pressing, or the cutters 106 may form the grooves. The grooves 112, 113, 115 are formed as shown in Fig. 19 and are coated on one side by stop-weld 120. The stop-weld may comprise aluminium oxide, silica or talc sprayed on, or a sooty oxy-acetylene flame may be directed on the surface to be coated, or the billet may be heated and a rod of metal stearate, an epoxide resin or a polysiloxane passed along the surface, or a polysiloxane grease may be applied. The shape of the ingot and the grooves are such that the amount of spreading of each core during subsequent rolling is identical, the grooves also forming lines of weakness in cooperation with the stop-weld 120. Prior to this rolling the hollow cores 21 are filled with a stopweld bar or material such as aluminium oxide, zirconium oxide, titanium oxide, sodium chloride, or polyethylene. The ends of the cores may be sealed. The billet 101 is then hot rolled by stands 140, 141, Fig. 23, e.g. at an initial temperature of 900‹ F. for an aluminium or aluminium alloy ingot, and wound into a coil 143 annealed in a furnace. The coil 143 is then unwound through cold rolling stands 144, Fig. 24, through an oven 146, between straightening rolls 147, to rolls 149 which engage the edges of the strip, Fig. 26. The edge portions 150 are removed by tearing along lines of weakness 161 and are guided away by rollers 154. The remainder of the strip may be severed into lengths 153 by shears 152 and then flexed along the lines of weakness 161 to form single can blanks, or, Fig. 26, wound around drums 177 the strips severing along the lines 161. A severed can blank 170 is expanded, Fig. 30, and the edges of the blank are hammered to reduce the projections 172. The ends of the expanded blanks may be flanged and provided with container ends.