GB550263A - Improvements in or relating to uniting metal members together by welding and the like - Google Patents

Abstract

550,263. Uniting by fusion. ORR, J. B. July 28, 1941, No. 9588. [Class 83 (iv)] In welding together a pair of members such as plates or sheets, each of which has a corrosion resisting plied side, the base metal portions are first welded, e.g. by fusion or flash welding, and the corrosion resisting sides are then welded by spraying weld metal thereon while maintaining the corrosion resisting side and weld metal at a temperature inhibiting loss of their corrosion resisting properties. The weld metal and the work in the vicinity thereof cool rapidly through the critical range and the more remote parts of the work do not reach such range. Carbon steel parts with a thin coating of stainless steel may thus be welded .together. The carbon steel sides 10 of such a compound plate &c. may first be united by carbon steel weld metal 12 or if desired by stainless steel weld metal, applied by ordinary gas or electric are welding. It may be applied either from the stainless steel side as shown in Fig. 1, or from the carbon steel side. The stainless steel side is kept below the critical range, viz., 1,200 to 1,800‹ F., by jets 14 of gas, preferably air, the quantity and velocity of which is controlled in accordance with the temperature of the stainless steel side which may be indicated by a thermometer &c. 15. The stainless steel weld metal 13 is then applied, preferably after heating the work from 600 to 1,200‹ F., or while the work is still hot from the previous operation by spraying a finely divided form. This may be effected by passing a gas under pressure through a nozzle 26 to spray metal melted from a rod 25 by an arc formed between a pair of carbon electrodes 24. The gas may be non-oxidizing or the weld rod may be coated with size, off grade flour or coal tar derivatives. In a modification rods may take the place of one or both of the carbons. In a further form powdered metal may be forced by air through a hose into contact with concentric rings of a welding gas flame or the metal may be vaporized and applied by vacuum. The stainless steel sides of the work in the vicinity of the joint may be previously roughed by shot or coal blasting &c. the stainless steel and weld metal applied thereto also during welding. The stainless steel side may be treated with nitric or sulphuric acid &c. after welding 'to improve its surface finish. Specifications 527,659 and 528,969 are referred to.