Improvements in or relating to stainless steel articles or objects and methods of treating or electroplating stainless steel surfaces

摘要

529,247. Producing metallic coatings on stainless steel articles. NATIONAL STANDARD CO. May 11, 1939, No. 14065. Convention date, June 22, 1938. [Class 41] [Also in Group XXII] Relates to means for electrolytically producing metallic coatings on stainless steel articles such as wire; when of copper or other lubricant metal, the coatings are of assistance in enabling the wire to be drawn by successive passings between dies to a smaller diameter. The annealed wire 2 is first passed through a 10 per cent. solution of sulphuric acid in an electrolytic bath 3 to remove scale, the wire being made the anode, a current density of 75 amperes per square foot of surface being used. After passing through a 10 per cent. hydrochloric acid solution in bath 4 and being washed in cold running water (not indicated in the Figures) the-wire passes as the cathode through a second 10 per cent. sulphuric acid deoxidizing bath 5, a current density of 30 amperes per square foot being used in this instance. From bath 5 the wire passes through cloths 6 soaked in sodium carbonate solution, first to neutralizing bath 7, also of. sodium carbonate solution, and from there through more cloths 8 soaked in sodium carbonate solution to a copper plating (copper cyanide) bath 9, where a current density of 30 amperes per square foot is employed. It is then drawn through dies 10, 11 (where a powdered sodium stearate lubricant is used in addition to the copper coating). Finally the copper coating is removed in a copper cyanide electrolytic bath 12.