Patent GB-1046798-A (GB)
Title: A method of bonding together pieces of preformed metal
Inventor: FARBER MILTON HORACE
IPC: B23K20/227
Filed: 1963-08-23
Abstract: 1,046,798. Making sheets; hollow ware; bearings; Jewelery; contacts; thermostats and crucibles; welding by pressure; Jointing by rolling. S. W. FARBER Inc. Aug. 23, 1963, No. 33537/63. Headings B3A, B3M and B3R. In bonding metal sheets, aluminium is sprayed on to that sheet or sheets to be joined not of aluminium and with the sprayed aluminium between them the sheets, heated prior to or at the time of bonding to a temperature not greater than the incipient fusion temperature of the sprayed aluminium, are pressed together. In one embodiment a sheet 1, Fig. 2 (not shown), of cast iron, sheet steel, stainless steel, titanium and alloys thereof, copper and alloys thereof, nickel and alloys thereof, zirconium or an alloy thereof in the general shape of a cooking vessel is cleaned mechanically or chemically and is coated with a sprayed 0À001 to 0À010 inch thick layer 2 of aluminium by feeding aluminium into an arc or oxy-acetylene flame and directing the particles against the vessel suitably masked. A sheet or slab of aluminium 4 is cleaned and this sheet and the coated sheet 1 are heated to a temperature up to the incipient fusion point of the aluminium preferably to at least 550‹ F., the two pieces are brought together in a die 5, 6, the upper portion 6 being slightly convex and pressure is applied so that the aluminium piece is reduced in thickness between 1% and 8% preferably 5%. The product is stress relieved by heating to 550‹-750‹ F. and allowing to cool slowly and then it is placed in a caustic bath. A stainless steel frying pan is heated to 700‹ F. and given a 0À004 inch sprayed coating of aluminium alloy, an aluminium alloy blank, planed and abrasively cleaned and the sprayed pan are heated to 800‹ F. and pressed in the die. Instead of the die being convex the aluminium blank may be made concave. The product is heated to 750‹ F. for stress relieving, immersed in a caustic bath and belt ground. In another embodiment sheet metal e.g. of stainless steel and copper is fed, heated preferably to 750‹ F., from two coils 10, 11, Fig. 5 (not shown), and a number of spray devices 12, 13 deposit a layer of aluminium 0À001-0À008 inch thick on both sheets except that if one sheet is of aluminium it need not be sprayed. The sheets are guided to pressure rolls 15, 16 heated to about 600‹ F. and pressed by back up rolls 17, 18 to bond the sheets together. In a modification the aluminium coatings are produced by a single row of plasma arc jets fed with aluminium powder adjacent the pressure rolls and in this case preheating of the sheets is not required. This preheating may be effected by ovens, induction heaters or flames. Three layers of metal may be joined by drawing three preheated sheets from three rolls, spraying the two pairs of adjacent faces with aluminium by four sets of flame sprayers or two sets of plasma jets and pressing the coated sheets together by heated rolls. Sheet metal is fed from coils 33, 34, 35, Fig. 11, preheated by heaters 36 to 750‹ F., aluminium sprayed by apparatus 37, heated in an oven or kiln 40 to 550‹ F.-750‹ F. fed past brushes 42 for engaging the aluminium sprayed surfaces, pressed together by heated rolls 44, 46, drawn through a stress relieving chamber 50 and coiled at 48. The following metals may be bonded; stainless steel to aluminium for cooking utensils, stainless steel to copper for pots and frying pans; steel to bronze for sleeve bearings, silver to stainless steel for jewellery, silver to copper for electrical contact, gold to nickel silver for jewellery, aluminium to mild steel for building panels, invar to aluminium alloy for thermostat element, nickel to stainless steel for reaction vessels, " Monel " (Registered Trade Mark) to carbon steel for kitchen counters, palladium to copper for crucibles &c., platinum to stainless steel for jewellery, aluminium to stainless steel for pots and stainless steel to annealed steel for pots. The pressure used for bonding may be produced by a high energy press, by a drop hammer or by a rotatable ball applied in a spiral path to the work as the work is rotated. The term aluminium includes both aluminium and aluminium alloys consisting principally of aluminium.