US3616342A - Process for the removal of metal powder and low metal oxides from the surfaces of bundles of wire which have been etched with sodium hydride - Google Patents

Process for the removal of metal powder and low metal oxides from the surfaces of bundles of wire which have been etched with sodium hydride Download PDF

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Publication number
US3616342A
US3616342A US690717A US3616342DA US3616342A US 3616342 A US3616342 A US 3616342A US 690717 A US690717 A US 690717A US 3616342D A US3616342D A US 3616342DA US 3616342 A US3616342 A US 3616342A
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wire
bath
bundle
removal
bundles
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Expired - Lifetime
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US690717A
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English (en)
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Arnold Lenz
Walter Rogler
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Dynamit Nobel AG
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Dynamit Nobel AG
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F1/00—Electrolytic cleaning, degreasing, pickling or descaling
    • C25F1/02—Pickling; Descaling
    • C25F1/04—Pickling; Descaling in solution

Definitions

  • PROCESS FOR THE REMOVAL OF METAL POWDER AND LOW METAL OXIDES FROM THE SURFACES OF BUNDLES OF WIRE WHICH HAVE BEEN ETCHED WITH SODIUM HYDRIDE This invention is directed to the cleaning of metals. It is more specifically related to the removal of rust and/or scale from wire coils.
  • Processes for reducing rust or scale on metal surfaces by immersing the metal objects in a bath consisting of molten caustic soda and/or caustic potash plus sodium hydride in a quantity of 0.5 to 3 percent of the weight of the caustic soda and/or caustic potash, and then removing the reduced coating from the metal surface by electrical treatment in an alkaline medium.
  • the electrical treatment involves passing a current through the object, first using the object as an anode, and then by polarity reversal, using the object as a cathode. ln the case of bundles of wire, particularly a coil, it is difiicult to remove the rust or scale from the interior of the bundle. Complete removal of the rust or scale is achieved only on the outer surface of the bundle. This is probably due to the fact that the current lines run only in the outer surface of the bundle.
  • one aspect of this invention resides in a process for the removal of rust and/or scale from the surface of a bundle of wire which process comprises etching the bundle of wire in molten caustic soda or molten caustic potash containing sodium hydride; and then passing an electric current through the bundle of wire while such wire is immersed in an alkaline medium having a lye content of at least about 60 percent.
  • the alkaline bath is maintained at up to about 25 C., preferably about to 20 C., above its solidification point.
  • the polarity of the current is reversed so that for part of the treatment the wire bundle is the anode and for part it is the cathode.
  • the rust or scale can be completely removed, even in the interior of the wire bundle, if the temperature and concentration conditions of the invention are sustained in the lye bath.
  • the metal compounds developing from the metal powder and the low metal oxides in the post-treatment settle out and are captured at the bottom of the lye bath in separate containers. This process may be carried out with agitation or in a quiescent state. ln steady operation the bath has an average iron content of approximately 0.1% Fe O ln the anodic and cathodic process the current passes through the suspended wire bundle, the lye bath and, as the counterelectrode, a plate made of corrosion-resistant steel s1 spended in the lye bath. The anodic treatment is completed as soon as a yellowish violet coating has formed in the interior of the bundle.
  • the process of this invention can be improved if an additional cathode is inserted through the center of the suspended wire bundle. ln the cathodic treatment that follows, and which is accomplished merely by reversing polarity while the arrangement remains the same, the yellowish violet coating is dissolved and is also chipped ofi by the cathodic evolution of hydrogen, so that the wire surface becomes metallically clean.
  • Example 1 A -kilogram wire bundle having an inside diameter of 400 to 500 mm., a wire diameter of 3 mm., and a scale content of 0.3 percent, is immersed, after hydride etching, into a lye bath containing 60% NaOH/KOH. The bath temperature is 70 C. The bundle is treated anodically for 20 minutes at a current of 1,500 amperes. A violet coating forms in the core of the bundle. In the cathodic treatment then following, which is also performed for 20 minutes at 1,500 amperes, the coating that developed in the anodic treatment comes of? completely.
  • the point of contact between the wire bundle and its hanger is changed by turning the wire bundle. Finally the wire is rinsed in cold water and protected against further corrosion by immersion in a lime bath.
  • Example 2 A wire bundle of the same kind as in example I is treated anodically and cathodically at 65 C. in a 60 percent caustic soda lye after the hydride etching. With a current of 1,500 amperes, the black coating on the metal is transformed within 20 minutes into a yellowish violet compound extending all the way into the core of the bundle. A cathodic treatment at 1,500 amperes for 20 minutes is required for complete cleaning. Then the bundle is rinsed in cold water and dipped in milk of lime.
  • Example 3 A wire bundle as in examples 1 and 2 is immersed, after hydride etching, into 60% KOH at a temperature of 75C.
  • the wire bundle is then rinsed with water and protected against further rusting with lime.
  • Example 4 A wire bundle of the same kind as in examples l to 3 is immersed after hydride etching into a bath of molten 100% NaOh/KOH at 215 C.
  • the anodic treatment is performed at 1,500 amperes for 5 minutes.
  • the yellowish violet coating that forms is not resistant and largely redissolves. What is left is an extremely thin yellowish coating which is entirely removed by the reversal of polarity (5 min. at 1,500 amp.).
  • the bundle is washed in cold water and then dipped in milk of lime.
  • Example 5 A wire bundle as in examples 1 to 4 is immersed in a bath of molten 100% NaOH at a temperature of 330 C.
  • the bundle is then washed in cold water and dipped in milk of lime.
  • Example 6 A bundle of wire as in examples l to 5 is immersed into a bath of 100 percent molten KOH at 370 C. After 5 minutes of anodic post-treatment at 1,500 amperes the bundle has assumed a yellowish color extending all the way into the core. For cathodic cleaning, 5 minutes are required. The bundle is washed in cold water to remove all the alkali and is then dipped in milk of lime.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
US690717A 1966-12-10 1967-12-11 Process for the removal of metal powder and low metal oxides from the surfaces of bundles of wire which have been etched with sodium hydride Expired - Lifetime US3616342A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DED0051750 1966-12-10

Publications (1)

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US3616342A true US3616342A (en) 1971-10-26

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US690717A Expired - Lifetime US3616342A (en) 1966-12-10 1967-12-11 Process for the removal of metal powder and low metal oxides from the surfaces of bundles of wire which have been etched with sodium hydride

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Country Link
US (1) US3616342A (enrdf_load_stackoverflow)
JP (1) JPS5121938B1 (enrdf_load_stackoverflow)
BE (1) BE707727A (enrdf_load_stackoverflow)
DE (1) DE1496785A1 (enrdf_load_stackoverflow)
GB (1) GB1203980A (enrdf_load_stackoverflow)
NL (1) NL6716716A (enrdf_load_stackoverflow)
SE (1) SE394896B (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6475289B2 (en) 2000-12-19 2002-11-05 Howmet Research Corporation Cleaning of internal passages of airfoils
WO2022159054A1 (en) * 2021-01-19 2022-07-28 Guney Celik Hasir Ve Demir Mam. San. Tic. A. S. System and method for providing surface cleaning of steel wire on apparatus used for efficient cleaning before galvanized coating

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1520705A (en) * 1976-04-01 1978-08-09 Allegheny Ludlum Ind Inc Electrolytic descaling of metals
JPS5788672U (enrdf_load_stackoverflow) * 1980-11-20 1982-06-01

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6475289B2 (en) 2000-12-19 2002-11-05 Howmet Research Corporation Cleaning of internal passages of airfoils
WO2022159054A1 (en) * 2021-01-19 2022-07-28 Guney Celik Hasir Ve Demir Mam. San. Tic. A. S. System and method for providing surface cleaning of steel wire on apparatus used for efficient cleaning before galvanized coating

Also Published As

Publication number Publication date
NL6716716A (enrdf_load_stackoverflow) 1968-06-11
DE1496785A1 (de) 1969-08-07
BE707727A (enrdf_load_stackoverflow) 1968-04-16
SE394896B (sv) 1977-07-18
JPS5121938B1 (enrdf_load_stackoverflow) 1976-07-06
GB1203980A (en) 1970-09-03

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