the process of consolidation of metallic product and product with metal are much more widespread codification)

摘要

1391923 Coding of steel substrates USS ENGS & CONSULTANTS Inc 30 May 1972 [1 June 1971] 25321/72 Heading C7F A steel substrate is non-deleteriously coded by contacting it with a solution or slurry of an oxalate, formate, citrate, acetate and/or malonate of Ni, Co, Mg, Zn, Cu, Pb and/or Cd to coat it with a film thick enough to give on thermal decomposition and subsequent diffusion, 0.5 to 20 mg of the cation per square foot of substrate, and heating the coated substrate above the decomposition temperature of said salt(s) to degrade the anion and diffuse the cation into the substrate surface. The steel may be precleaned electrolytically in alkaline solution; the salt may be applied by dipping, spraying, or brushing and decomposed at 1000‹F or more; the treated substrate may be cold reduced and/or coated with Sn, Cr or lacquer. The process is used by a manufacturer to introduce the above metals into steel in an amount detectable by X-ray fluorescence so that the origin of the steel can be traced, even after subsequent coating.