US3506487A - Process for the removal of scale from very scaly metal surfaces - Google Patents

Process for the removal of scale from very scaly metal surfaces Download PDF

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Publication number
US3506487A
US3506487A US689280A US3506487DA US3506487A US 3506487 A US3506487 A US 3506487A US 689280 A US689280 A US 689280A US 3506487D A US3506487D A US 3506487DA US 3506487 A US3506487 A US 3506487A
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US
United States
Prior art keywords
scale
removal
alkali
metal surfaces
metal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US689280A
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English (en)
Inventor
Arnold Lenz
Walter Rogler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dynamit Nobel AG
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Dynamit Nobel AG
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Publication date
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Classifications

    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23GCLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/28Cleaning or pickling metallic material with solutions or molten salts with molten salts

Definitions

  • 'It is an object of the present invention to provide an improved process for descaling and derusting metal surfaces.
  • Another object of the invention is to provide an improved process for descaling and derusting metal surfaces which can be simply and economically effected.
  • Still another object of the invention is to provide an improved process for descaling and derusting metal surfaces which does not disadvantageously affect the desirable properties of the metal articles.
  • the above objects may be accomplished by immersing the article to be descaled into a molten alkali bath which contains from 0.3 to 5% of an alkali metal hydride, the alkali bath being used having a temperature of at least 185 C., the treatment being carried out so that the alkali penetrates only up to 50 to of the layer of scale. Thereafter the article is chilled down to room temperature by immersion into a water bath, washed free of alkali and subjected to a mechanical aftertreatment for removal of the loosely adhering scale,
  • the process has the additional advantage that the caustic needs to penetrate the scale or rust layer only partially, with the result that the consumption of alkali hydride is correspondingly reduced as compared with the prior-art cleaning process.
  • the scale or rust layer partially reduced by the caustic to the metallic or low oxide state adheres so loosely to the metal surface, after the chilling, that it can easily be removed by mechanical treatment, which is another advantage over the electrical post-treatment.
  • the molten caustic can be sodium hydroxide, potassium hydroxide or mixtures of the two.
  • the alkali metal hydride is preferably sodium hydride although potassium hydride and lithium hydride can also be used.
  • shaking apparatus are suitable for coils and spirals, while largesurface objects are cleaned off by water under pressure and compressed air or brushes.
  • EXAMPLE I A 350-kg. coil of rolled wire having a wire size of 6 mm. and a scale content of about 10 kg. per metric ton was immersed in a molten bath of NaOH/KOH with a hydride content of 0.9 weight percent calculated on NaOH/KOH at a temperature of 240 C. for 30 minutes with gentle swinging back and forth. Thereafter the coil was chilled in water down to room temperature and rinsed free of alkali,
  • the rinsed coil was then shaken on a shaking table, the loose layers flaking Off, the bright metal surface being thereby revealed.
  • Example II The procedure of Example I was repeated. However following rinsing of the coil the same was subjected to jets of compressed air.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
US689280A 1966-12-13 1967-12-11 Process for the removal of scale from very scaly metal surfaces Expired - Lifetime US3506487A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DED0051764 1966-12-13

Publications (1)

Publication Number Publication Date
US3506487A true US3506487A (en) 1970-04-14

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ID=7053642

Family Applications (1)

Application Number Title Priority Date Filing Date
US689280A Expired - Lifetime US3506487A (en) 1966-12-13 1967-12-11 Process for the removal of scale from very scaly metal surfaces

Country Status (6)

Country Link
US (1) US3506487A (enrdf_load_html_response)
BE (1) BE707800A (enrdf_load_html_response)
FR (1) FR1548875A (enrdf_load_html_response)
GB (1) GB1210409A (enrdf_load_html_response)
NL (1) NL6716881A (enrdf_load_html_response)
SE (1) SE346128B (enrdf_load_html_response)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3873280A (en) * 1972-08-22 1975-03-25 Merit Abrasive Prod Descaling of steel strip
US3951681A (en) * 1973-11-01 1976-04-20 Kolene Corporation Method for descaling ferrous metals
US4339281A (en) * 1981-08-20 1982-07-13 Rca Corporation Shank diamond cleaning
US5803978A (en) * 1996-07-19 1998-09-08 Westinghouse Electric Corp. Method of removing blades from a turbo machine

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2377876A (en) * 1941-04-23 1945-06-12 Du Pont Metal cleaning process and composition
US2380284A (en) * 1942-12-21 1945-07-10 Du Pont Method of cleaning ferrous metal articles
US2717845A (en) * 1947-01-09 1955-09-13 Roy E Carter Metal descaling methods
US2796366A (en) * 1955-10-31 1957-06-18 Du Pont Process and bath for descaling metals

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2377876A (en) * 1941-04-23 1945-06-12 Du Pont Metal cleaning process and composition
US2380284A (en) * 1942-12-21 1945-07-10 Du Pont Method of cleaning ferrous metal articles
US2717845A (en) * 1947-01-09 1955-09-13 Roy E Carter Metal descaling methods
US2796366A (en) * 1955-10-31 1957-06-18 Du Pont Process and bath for descaling metals

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3873280A (en) * 1972-08-22 1975-03-25 Merit Abrasive Prod Descaling of steel strip
US3951681A (en) * 1973-11-01 1976-04-20 Kolene Corporation Method for descaling ferrous metals
US4339281A (en) * 1981-08-20 1982-07-13 Rca Corporation Shank diamond cleaning
US5803978A (en) * 1996-07-19 1998-09-08 Westinghouse Electric Corp. Method of removing blades from a turbo machine

Also Published As

Publication number Publication date
GB1210409A (en) 1970-10-28
BE707800A (enrdf_load_html_response) 1968-04-16
NL6716881A (enrdf_load_html_response) 1968-06-14
SE346128B (enrdf_load_html_response) 1972-06-26
FR1548875A (enrdf_load_html_response) 1968-12-06

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