GB556098A - Improvements in the uniting of metals - Google Patents

Abstract

556,098. Coating with metals. LINDE AIR PRODUCTS CO. May 15, 1942, Nos. 6592 and 6593. Convention dates, May 2, 1941 and June 21, 1941. [Class 82 (ii)] [Also in Group XXII] In cladding corrodible metal such as iron or steel with a non-corrodible metal such as copper, brass, bronze, stainless steel and alloys of copper, nickel and iron, the surface of at least one of the elements has its skin removed by desurfacing flame and the second element applied to the clean surface while hot and the elements united by pressure. One or more faces of the bare metal may be coated in one or more passes. A metal slab W, at rolling temperature or heated in a furnace 10 to rolling temperature, is fed over a rolled table 11 past a head T, provided in front with a unit D such as that described in Specification 534,174, having a desurfacing flame 13 and 'in rear with a unit R having nozzles 18, 20 respectively for supplying flux and. molten metal and then passes through pressing rolls 12. The desurfacing flame provides also an inert atmosphere to assist in the prevention of oxidation of the cleaned surface prior to coating. The flame 13 may extend right across the slab or may form a recess therein and the lateral edges of the slab may be engaged by the edge 23 of the unit R so as to level the molten metal supplied to the recess. The ends may also be left unsurfaced and may be cut off as material passes through the rolls. The surfaces left by the desurfacing flame have slight longitudinal grooves which assist in retaining the coating metal. In a modification the slab at rolling temperature may first pass through blooming rolls 31, then under the desurfacing flame 13 and then under nozzles 18<SP>1</SP>, 20<SP>1</SP> from which are supplied respectively flux and powdered metal or a mixture of powdered metals when an alloy coating is desired, then under blowpipes 32 and finally through pressing rolls 12. In a modification of this form the flux and powdered metals may be mixed and supplied through the same nozzles. A mixture for a chromium-nickel-steel coating may consist of carbon 0.08 to 0.2 per cent., manganese 1.5 per cent., silicon 0.75 per cent., chromium 18 per cent., nickel 8 per cent., and the rest iron. In a further form the coating may be applied by metal sprayers contained in a muffle having an inlet through which an inert gas may be supplied. Excess metal may be reclaimed from the muffle. In another form the muffle 40<SP>1</SP> may contain in sequence flux and powdered metal supply nozzles 18, 20<SP>1</SP>, blowpipes 32, and flux and molten metal supply nozzles 18<SP>1</SP>, 20, so as to apply the coating in two layers. When blowpipes are used in the muffle no inert gas need be supplied. For forming a number of superposed layers a series of hoppers and blowpipes is used. The coating metal may be fed in strip form 45 through rolls 30<SP>1</SP> and may pass through a preheating furnace 10<SP>1</SP>, if necessary, and then into a muffle 46 in which it is led over a roller 51, then over a desurfacing unit 52, which may be provided with a flux supply 64, then under a row of preheating blowpipes 53 and then together with the slab W between welding rolls 12, the parts in the angle between the strip and slab being further heated. by welding blowpipes. 56. The slab W in order to reach the rolls 12 has passed through blooming rolls 30, preheater 10, desurfacer 47 containing flux supply 63 and over preheating blowpipes 48. The flux may be supplied in powder form or in liquid form. Volatile liquid fluxes may also be conveyed by the blowpipes. The pressing rolls 12 may be replaced by a series of pairs of rolls. Specification 507,262, [Group XXII], also is referred to.