GB646377A - Improvements in and relating to soldering and brazing - Google Patents

Abstract

646,377. Powder metallurgy. BRIGGS, J. C., and THESSCO INDUSTRIAL RESEARCH, Ltd. March 11, 1947, No. 6738. Drawings to Specification. [Class .83 (iv)] Soldering and brazing.-A soldering or brazing element consists of an aggregate of distinct particles of powdered metals in the proportions required for producing when melted a solder alloy, the aggregate being preformed into the shape of a joint which is to be made and retaining its shape by adherence between the particles. The metal powder may be mixed with a powdered flux and/or deoxidiser, or the flux and deoxidiser may be introduced in liquid form to the previously compacted slab. Compressing may be accompanied by heat treating. The article may be formed direct from the powder in disc, ring, washer, &c. form, or from a small ingot. The metal powders may be tin and lead or a tin-lead alloy and the flux may include resin, fluoride, and/or borate, or borax and/or boric acid, and the deoxidiser may be silicon or phosphorus. The brazing composition may comprise 58 per cent of copper, 40.6 per cent of zinc, 1 per cent of silver and 0.4 per cent of silicon to which may be added 2 per cent of flux, such as borax or boric acid. Compression is effected at 6 tons per sq. inch and heat treatment then effected at 710‹ C. Another composition consists of 30 per cent silver, 25 per cent copper, 25 per cent zinc and 20 per cent cadmium, together with from 2 to 12 per cent of flux which may consist of a fluoride or a mixed borate fluoride, or borax and/or boric acid. Heat treatment may be effected at 530‹ C. A further composition may consist of copper, silver and phosphorus with 5 per cent of a borate fluoride or borax-boric acid flux. A solder element, particularly one containing silver, may be used in soldering in a furnace with controlled atmosphere. Soldering may be effected with electric resistance or induction heating.