GB1177711A - Method of making Sheet Metal Panel - Google Patents

Abstract

1,177,711. Making cavity panels; jointing by rolling. OLIN MATHIESON CHEMICAL CORP. 31 July, 1967, No. 35168/67. Headings B3A and B3M. A sheet metal panel with internal cavities, e.g. a heat exchanger is made by bonding two metal sheets together by hot rolling, at least one of the sheets having one surface coated with a stop weld material, placing a nozzle 36 between the sheets and inflating portions of the sheets between dies 24, 26 by fluid pressure. The sheets are preferably an alloy of copper, aluminium, magnesium or steel. The inner surfaces are cleaned by wire brushing, solvent degreasing or etching in acid. The stop weld material may be applied by spraying or painting through a stencil or squeezed through a silk screen. The stop weld is omitted from the marginal edge and a narrow portion 14 of stop weld is provided between the edge of the composite and the interior. Suitable stop welds are graphite and water glass mixture, zinc oxide, kieselguhr, flint, talc powder, cork, clays and mixtures thereof. For sheets of aluminium alloy the composite is heated to 800‹ to 1000‹ F., e.g. 950‹ F., and hot rolled to a 65% reduction. The composite is then cold rolled and annealed. The sheets are prised apart at the area 14 and the nozzle 36 inserted. The dies may have various shapes and cavities of unequal sizes. The degree of bonding may be varied by different types and different thicknesses of stop-weld. The thickness may be reduced by wire brushing to remove part of the stop-weld with extreme accuracy. Certain areas of the composite may be bonded by this method with a weaker bond than other areas. The cavity panel may be used as a heatexchanger, a sheath for an electric cable, or a heating element.