GB369982A - Improvements in or relating to metal tubing and the manufacture of the same - Google Patents

Abstract

369,982. C o a t i n g. ARMSTRONG, J. J.. V., 12, Church Street, Liverpool.- (Bundy Tubing Co. ; 4815, Bellevue Avenue, Detroit, Michigan, U.S.A.) Oct. 31, 1930, No. 32727. [Class 82 (ii).] Metal tubes having longitudinal joints with butt, lap, or lock seams, seams comprising interengaging projections and recesses, and plural ply tubes are united at the joint and simultaneously coated inside and outside with corrosion-resisting metal such as copper by passing the tube and a quantity of copper in the ratio of 0À15 ozs. per square foot through a furnace maintained at 2000‹ F. and containing a reducing atmosphere at such a speed as to cause the copper &c. to melt and flow into its seam and over both surfaces of the tube. The stock may consist of steel and of the alloy sold under the registered Trade Mark "Monel," and the coating and binding metal may be of copper or alloys thereof such as constantan or copper-silver or copper-gold alloys. Strip stock coated on each face with a layer of copper 0À0001 inch thick may be used, the coating being preferably effected by electroplating or by covering with copper powder mixed with a carrier and applying heat. The tube 2 is passed through an electric or other muffle furnace 1 and then through a water-jacketed cooling chamber, the furnace and chamber being supplied through conduit 6 with a non- oxidizing or reducing atmosphere such as hydrogen, carbon monoxide, or gas obtained by cracking illumir.ating gas. When using copper as the coating metal, a steel tube of # inch diameter and 0À015 inch thick is passed at two feet per minute through a furnace 6 feet long and at a temperature of 2000‹ F. Metal in wire, powder, or block form may be applied in addition when a more thinly coated strip is used or when it is desired to provide a thick coating. Specifications 347,723 and 359,731 are referred to.