Classifications

• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
  • G06K1/00—Methods or arrangements for marking the record carrier in digital fashion
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12778—Alternative base metals from diverse categories
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12861—Group VIII or IB metal-base component
  • Y10T428/12951—Fe-base component
  • Y10T428/12972—Containing 0.01-1.7% carbon [i.e., steel]

Definitions

• Our invention relates generally to a metallic product which has been treated to make it identifiable at any stage of manufacture. More specifically, our invention relates to a product having a steel substrate which is so treated.
• the steel substrate to be coded is cleaned in any conventional manner. We prefer to use steel which has been electrolytically cleaned in an alkaline solution. The cleaned substrate is submerged in a bath of the coding compound and dried. The dried substrate, having a thin film of the coding compound on its outer surface, is then heated to a temperature high enough to degrade the coding compound and to diffuse the metallic cation of the coding compound onto the surface of the substrate. Finally, if a coating is desired, the coded substrate is plated or coated with the desired coating.
• Our process thus provides an easy method of coding a steel substrate requiring only one inexpensive step and produces a product with an unblemished surface, identifiable without deplating of the coating, if a coating is present.
• the coding compound should be a metallic salt whose metallic cation is not present in the steel substrate, or which is present in only a minor quantity, and which does not detrimentally affect the surface of the substrate, and whose anion degrades at or below the annealing temperature without producing a residue which would remain on the steel.
• nickel, cobalt, magnesium, aluminum, calcium, zinc, copper, lead and cadmium are suitable metallic cations.
• nickel, cobalt, magnesium and copper are suitable.
• Suitable anionic species include oxalates, formates, malonates, acetates and citrates.
• water is used as the solvent for the coating compound, we have found the formates and acetates of nickel and cobalt to be especially suitable.
• the coding compound may be applied by spraying, dipping, brushing or any other suitable and convenient means. Either the entirety or merely a portion of the substrate may be coated. The coded material is allowed to dry, to prevent solvent from entering the furnace, and is then annealed according to conventional practice.
• the solutions of the coding compound are preferably saturated with the coding compound.
• a slurry of the coding compound may be used.
• Low carbon steel such as is conventionally used as a substrate for plating with tin or chromium is the preferred substrate.
• the entrained solids picked up by the substrate as it moves through the coding bath remain on the substrate and increase the final concentration.
• more dilute coding solutions may be used. This procedure allows a wide variation in the concentration of tracer metal in the substrate after annealing.
• the dried metallic salt should be present on the surface of the substrate in a concentration of from about 2.5 mg./ft. to about mg./ft. In some instances, it is desirable to cold reduce the coded substrate to meet gage and strength requirements. In such cases, the concentration of the dried metallic salt should be at the higher portion of the stated range.
• the temperature of the bath is not critical. It is preferred to use the bath at room temperature to avoid the necessity of providing heating or cooling apparatus.
• the substrate, coated with the coding compound is heated to decompose the anion of the coding compound, which then escapes into the air, and to diffuse the cation of the coding compound onto the surface of the substrate.
• This degradation and diffusion step is preferably accomplished by the standard annealing operation for the steelsubstrate. However, it may also be accomplished by heating in a furnace to a temperature above the decomposition temperature of the coding compound and preferably above 1000 F.
• overlay we do not intend to be limited to tin and chrominum, the two most common metals plated onto the steel substrate. Other metals may be used. Further, our invention is not limited to metallic overlays. We have found that organic coatings, and lacquer in particular, may also be used with our identification system.
• X-ray fluorescence is a means of analysis especially suited for use with our system and may be used in instances where the plating or coating on the substrate is not above about mg./ sq. ft. in thickness. Where this thickness is exceeded, deplating or decoating is necessary as a preliminary step to analysis either by X-ray fluorescence or by conventional wet methods.
• our process limited to plated or coated materials, although we anticipate it to have its greatest use in this portion of the art. It is also possible to use our system to identify the source of manufacture of uncoated or unplated material, by following the steps of our process as outlined above, but with the deletion of the plating step.
• the tracer metal may already be present in the substrate, provided it is present in such small amounts that the addition of the tracer metal gives an analytically detectable increase in concentration.
• EXAMPLE 1 A clean sheet of black plate (cold-reduced low carbon steel sheet) was dipped in a saturated aqueous solution of cobalt formate held at 78 F. This solution contained 13.4 grams of cobalt per liter. The sheet was removed from the bath when it was completely wetted with the coding solution and placed on a drying rack to dry in the air. The dry coated material was annealed at 1200 F. for 30 seconds in an annealing furnace under a protective atmosphere containing about 6% hydrogen and 94% nitrogen. The annealed product was cooled and transferred to the plating operation.
• the black plate was rinsed in water and subjected to electrolytic pickling in a 5 weight percent H 80 solution and a current density was 100 amperes/sq. ft. after which it was fed to a chromium plating bath.
• the chromium plated black plate was then analyzed using X-ray fluorescence and was found to contain approximately 14 milligrams/ sq. ft. of cobalt.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Theoretical Computer Science (AREA)
• Electroplating Methods And Accessories (AREA)
• Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
• Chemically Coating (AREA)
• Chemical Treatment Of Metals (AREA)

Priority Applications (14)

Applications Claiming Priority (1)

Publications (1)

Family

ID=22528651

Family Applications (1)

Country Status (14)

Cited By (1)

• 1971
  • 1971-06-01 US US00149064A patent/US3827903A/en not_active Expired - Lifetime
• 1972
  • 1972-05-23 CA CA142,783A patent/CA961712A/en not_active Expired
  • 1972-05-23 ZA ZA723535A patent/ZA723535B/xx unknown
  • 1972-05-25 AU AU42705/72A patent/AU465711B2/en not_active Expired
  • 1972-05-30 GB GB2532172A patent/GB1391923A/en not_active Expired
  • 1972-05-30 AR AR242254A patent/AR193261A1/es active
  • 1972-05-30 BE BE784165A patent/BE784165A/xx unknown
  • 1972-05-31 BR BR003536/72A patent/BR7203536D0/pt unknown
  • 1972-05-31 IT IT25158/72A patent/IT960650B/it active
  • 1972-05-31 DE DE19722226544 patent/DE2226544A1/de active Pending
  • 1972-05-31 ES ES403358A patent/ES403358A1/es not_active Expired
  • 1972-05-31 FR FR7219572A patent/FR2141129A5/fr not_active Expired
  • 1972-06-01 TR TR17433A patent/TR17433A/xx unknown
  • 1972-06-01 NL NL7207446A patent/NL7207446A/xx unknown

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