Patent GB-847150-A (GB)
Title: Improvements in or relating to methods of making internally slitted strip material
IPC: B21D53/04
Filed: 1957-12-19
Abstract: 847,150. Making composite sheets and billets; casting composite billets. REVERE COPPER & BRASS Inc. Dec. 19, 1957 [July 1, 1957], No. 39510/57. Classes 83 (1) and 83 (2). A method of making elongated internallyslitted metal strip, which slits are capable of being expanded by fluid-pressure to form fluidconducting passageways, comprises forming a metal slab having between its opposite faces one or more interior passages of flattened cross-section extending longitudinally thereof, said passages being filled with stop-weld material, applying metal to at least one face of said slab to form a relatively thick billet of which the metal of the slab forms an integral part, and rolling said billet for elongating it and reducing its thickness to move the opposite widthwise faces of said passages substantially into contact, and for spreading the weldpreventing material along said passages to prevent welding together of the opposite faces of said passages while the billet is being rolled. The preliminary billet 1 has, intermediate its opposite faces 3, a row of rods 5 of stop-weld material, e.g. graphite, soapstone or a mixture of talc, magnesia or alumina, as disclosed in Specification 784,484, or said rods may be strips cut from pressed-board of pulverizable vitreous fibres as disclosed in Specification 799,700, or they may be made of boronnitride. The billet, produced as disclosed in the above prior Specifications, is hot-rolled into strip from which slabs 7 are cut. Each slab is thickened to form a second billet 17, by casting metal against the faces 15 of the slab after the faces have been cleaned by pickling, sandblasting or scalping. A different metal is preferably used for the build-up metal for reasons of economy, e.g. a slab of copper may be built-up with brass consisting of 70% Cu and 30% zinc. The second billet is then rolled to produce the slitted-strip 19, in which the opposed faces 21 of the passages 11 have been moved substantially into contact. Alternatively, the second billet 17 is rolled to partially reduce it, and lengths are severed therefrom for use as slabs in forming a third thick-billet, which is rolled to form the strip, and so on. Also, any of the slabs produced from any of the thick-billets may be built-up to form a further thick-billet, by placing against one or both of the cleaned faces of the slab the cleaned face of a second slab of the same or different metal, securing the slabs together at their edges, and cold or hot-rolling the assembly to weld the slabs together. Casting.-The casting-mould comprises a water-jacketed base 31 and face-plates 27, 29, backed by water-jacketed members 37, 39 respectively. The upper flanges of the members 37, 39 support a removable pouring-box 57. The slab 7 is positioned midway between the face-plates of the mould, and is held in position by graphite plates 61, 63, the lower plates 61 fitting in grooves in the mould-end plates to prevent them from floating to the surface of molten metal. The temperature of pour is such as to melt the outer portions of the slab, but without melting any portion of the metal down to the passages containing the stop-weld material (see above). When deoxidized copper is used, the pour temperature is 2100‹ F., that is about 150‹ to 200‹ F. above the liquidustemperature of the metal. The preliminary billet 1 may be cast in the same mould by substituting graphite positioning plates 71, 73, Fig. 8, for the upper plates 63, and plates 75, 77, Fig. 9, for the lower plates 61.