GB912742A - Metal casting apparatus - Google Patents

Abstract

912,742. Continuous-casting machines; making foil. HAZELETT STRIP-CASTING CORPORATION. March 17, 1959 [March 17, 1958], No. 9271/59. Classes 83 (1) and 83 (2). Apparatus for casting metal between a pair of movable flexible bands 20, 22 to form strips comprises spaced rollers 44, 78, 80, 82, 242, 86 for guiding the bands, and a plurality of means 23, 25 for supplying coolant to the reverse surfaces of the bands. Metal, at a rate controlled by a screw-adjusted plug 6, Fig. 17, flows into a pool B in front of the entrance to the casting section formed by the thin highly-tensioned steel bands 20, 22 set at an angle of 5-10 degrees to the horizontal. The bands are cooled by water, containing sodium chromate, drawn from a reservoir 26 by a centrifugal pump through conduits 31, 136 and supplied to the nozzle and header assemblies 23, 25. The width of the strip is determined by the spacing between movable dams 28, 30, each consisting of T-grooved steel blocks threaded on to a metal strap. The dams are guided by stationary bars 32, 34, 54 and plates 48, the metal being maintained in the pool B up to a mark on one of the stationary bars 32. The bars 32, 34 also carry depending guides 56 and are supported at their ends for vertical adjustment on brackets 60, 62 which are adjustable transversely so that the width and thickness of the strip may be varied. Tubes supplied with cooling water from the conduit 31, pass through the bars 32, 34. The curved ends of the bars 32, 34 which engage the belt 20 are cooled by liquid supplied by adjustable sponges 78. The nozzle and header assemblies 23, 25 produce an unconfined liquid film on the bands, the cadmium-plated back-up rollers 86 being grooved to allow a free passage of the liquid. Each upper assembly 25 has a scoop 91 which directs the upper layer of the film into a gutter 102 and a series of nozzles 90, set at 10 degrees or less, which direct further fast-moving liquid along the band, causing the layer next to the band to accelerate. To increase the cooling effect, the band may be roughened by sand-blasting. Successive rows of nozzles are staggered relatively to each other. The back-up rollers 86 are also staggered longitudinally and are spaced more closely in the direction of travel of the strip. Larger coolant nozzles are used under the bath B than downstream. Coolant is also supplied through conduits 156, 154 to nozzles 158 located in grooves 152 in the roller 44, and from a conduit 162 to nozzles 164 passing round grooves in the roller 80. The machine has a frame composed of beams 188, 189, 190, having lifting lugs 197, the lower band being carried on a cantilever structure pivotally connected to the frame to prevent forces due to lifting being transmitted to the band supports. Rollers 230 attached to bell-crank levers operated by fluid-pressure devices 234 tension the bands. The upper band is carried on a structure on a pivoted arm 270 raised and lowered by a fluid-pressure device 255 and guided by rods 262, 264 supported by the lower band structure. Probes engage the edges of the bands and actuate switches to control fluidpressure means 290 which, through levers 295, raise one side of the roll 80 or 78. Tilting of a roll causes the band to be adjusted to a central position. The rolls are also reversely crowned to maintain the bands flat. Aluminium, copper or brass may be cast and aluminium foil of 0.003 inch thickness may be rolled from cast strip of ¢ inch thickness with only one annealing operation. Specifications 837,473, 837,474, 837,475 and 912,744 are referred to.