US3552404A - Installation for the descaling of metals - Google Patents

Installation for the descaling of metals Download PDF

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Publication number
US3552404A
US3552404A US706108A US3552404DA US3552404A US 3552404 A US3552404 A US 3552404A US 706108 A US706108 A US 706108A US 3552404D A US3552404D A US 3552404DA US 3552404 A US3552404 A US 3552404A
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United States
Prior art keywords
container
bath
molten
alkali metal
metal
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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
US706108A
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English (en)
Inventor
Rudolf Kuhn
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Evonik Operations GmbH
Original Assignee
Degussa GmbH
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING 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
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G3/00—Apparatus for cleaning or pickling metallic material
    • C23G3/02—Apparatus for cleaning or pickling metallic material for cleaning wires, strips, filaments continuously
    • C23G3/021—Apparatus for cleaning or pickling metallic material for cleaning wires, strips, filaments continuously by dipping
    • C—CHEMISTRY; METALLURGY
    • C23—COATING 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
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/28—Cleaning or pickling metallic material with solutions or molten salts with molten salts
    • C23G1/32—Heavy metals
    • C—CHEMISTRY; METALLURGY
    • C23—COATING 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
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G5/00—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents

Definitions

  • salt bath processes have been developed which are significantly short and have more limited process times than is required with the'acid treatment processes.
  • 'Such salt bath processes include those involving the use of molten alkaline salts, in which the scales are more or less given a preremoval treatment with the aid of direct electrical current in order to assure the quick removal of the scales in a subsequent heat treatment in the molten salt, as .well as processes in which a to be treated for the removal of scales therefrom.
  • An object of the present invention is to provide an installation in which to conduct the novel process of this invention.
  • a further object o f-the present invention is to provide an in- I 'stallation in which to conduct thenovel process of this invention.
  • the essence of the process of the present invention involves treating the metal to bedescaled with molten sodium metal, which treatment is preferably both preceded and followed by treating the metal with molten alkali metal hydroxide.
  • FIG. 1 is a side view of an installation in which the process disclosed maybe conducted.
  • FIG. 2 is an end view of the installation of FIG. 1.
  • the molten sodium metal treatment is preferably conducted at 230 to 700 C in about 60 to 5 seconds.
  • the molten sodium treating process can be further improved if the metal to be treated is pretreated or dipped in molten alkali metal hydroxide for a short time before the molten metal treatment.
  • the alkali metal hydroxide used is preferably sodium hydroxide. Molten mixtures of alkali metal hydroxides and alkali chlorides can also be used.
  • the pretreatment with alkali metal hydroxide is preferably conducted at 230 to 700 C. for 5 to 60 seconds. The wetting and resulting descaling of the surface of the metal being treated is so free of objectionable features that the descaling process is completed within a very short time without any trouble.
  • the alkali metal hydroxide bath which-is used in conjunction with the actual pickling process, which latter process is conducted in the molten sodium metal, can be used as means for sealing the sodium metal processing chamber from the atmosphere.
  • the alkali metal hydroxide melt which is used for pretreating the object to be descaled can also be used to pre heat such objects.
  • An alkali metal hydroxide bath can also be used as a post-descaling treatment in order to act as a scavenger and remove from the metal object being processed not only pieces of sodium metal that may adhere to the metal object as it leaves the sodium metal bath; but also sodium oxide reaction products that may form during the descaling step.
  • the pieces of sodium metal and sodium oxide reaction products that are taken up by the alkali metal hydroxide bath can be readily converted into sodium hydroxide upon contact with moisture in the atmosphere.
  • the molten sodium metal bath is preferably blanketed with an inert gas which will not react with the sodium metal.
  • the purpose of this inert gas is primarily to seal off the molten sodium metal bath from gases or other components of the atmosphere which would either react with the sodium metal or with the metal being processed under the prevailing process conditions. Examples of the undesired gases or other compounds are oxygen, hydrogen, water. Nitrogen is the preferred inert gas to be used as the blanketing medium.
  • a metal processing installation in which the process can be carried out can be constructed in such a way that the molten sodium metal is allowed to float on top of the molten alkali metal hydroxide bath.
  • the sodium metal bath can be isolated from the atmosphere by means of a tower type structure erected over the sodium metal bath.
  • Elongated metal objects, such as, wire and bands, to be treated in the sodium metal bath can be fed continuously through the bath and the tower type structure surrounding the bath by means of feeder devices,
  • shaped container has a wide open top and a narrow open bottom whereby an interface between molten sodium metal and molten alkali metal hydroxide sets in inside the narrow open end of the funnel shaped container.
  • FIG. 1 shows a side view of the installation
  • FIG. 2 shows an end view of the same installation.
  • the installation consists essentially of a furnace which has a wall 1 and a heating chamber la, an open topped trough or vat 2 for the molten alkali metal hydroxide 2a, an open topped container 3 for the molten sodium metal bath 3a, and airtight housing 4 and feeder or guide rollers 5.
  • Walls 4a of housing 4 extend on all sides down into bath 2a and housing 4 provides in combination with the molten alkali metal hydroxide 2a, an air tight area 7. Area 7 is thus bounded on its top and sides by housing 4 and at its base by the top of bath 2a. Area 7 completely isolates bath 30 from contact with the atmosphere, and during the operation of the installation area 7 is charged with an inert gas. The portions of the top of bath 2a which are outside walls 4a of housing 4 are in contact with the atmosphere.
  • An elongated metal object which is to be treated using the process of the present invention is fed into and through the installation, in the direction of the arrow, by means of guide rollers 5.
  • the metal object passes first through the NaOH bath, then through the Na bath and again through the NaOH bath before it leaves the installation.
  • the furnace maintains both the NaOH bath and the Na bath in a molten condition.
  • the NaOH bath is heated directly through its container wall 2 by means of heat generated in heating chamber In.
  • the sodium is in turn heated by the molten NaOH.
  • the sodium bath 3a is housed in funnel shaped container 3.
  • Container 3 may be suspended from above in the NaOl-l bath or it may be supported by a base which is itself resting on the bottom of trough 2.
  • the walls of the lower half of container 3 slope inwardly to provide a narrow, neck 6 which is open at the bottom thereof.
  • Neck 6 extends into the NaOH bath 2a in such a way as to leave a distance, on all sides of it, between it and the walls and base of trough 2.
  • the dissolved N320 will not be an impurity in the molten sodium hydroxide since the Na O will react with moisture in the air that is absorbed into the molten sodium hydroxide and will form sodium hydroxide. i.e.. Na O-j H O- 2 NaOH.
  • the moisture in the air can enter the sodium hydroxide where the molten sodium hydroxide is exposed to the atmosphere. i.e.. that portion of the molten sodium hydroxide bath which is outside walls 411.
  • the molten sodium hydroxide can be used as an air tight sealing means, in combination with airtight housing 4, in order to keep moisture and other materials in the air from reaching and reacting with the molten sodium.
  • Housing 4 is so constructed that continuous metal wire or bands can be processed therein under an inert atmosphere from the time the wire or band enters the molten sodium hydroxide for the first time until it leaves the molten sodium hydroxide at the end of the process. in this way slits are not needed in walls 4a in order to provide ingress and egress means for the wire and bands. Particles of sodium metal that may adhere to the band after the band leaves the molten sodium bath are readily taken up in the molten sodium hydroxide the second time the band passes through bath 2a, and thus before the band passes out into the outside atmosphere.
  • housing 4 is constructed wide enough so that there is sufficient open space on the surface of bath 20 between walls 4a of housing 4 and walls 3b of container 3 as to allow for the removal of impurities in the form of sludge from under container 3 in bath 2a through such open surface space.
  • two separate alkali metal hydroxide baths placed in separate troughs can also be used.
  • the sodium melt could also be housed in a separate trough shaped container of its own and the three troughs could still all be housed under a single air tight housing.
  • the elements of construction which are to come in contact with the molten alkali metal hydroxide should be such as are capable of withstanding attack from such hydroxides.
  • the sealing of the guide roller shafts 8 which are to pass through housing 4 can be done with stuffing' Boxes in order to maintain the air tight integrity of housing 4.
  • the heat generated in the heating area 10 of the furnace can be generated electrically, as by using resistance elements, or by burning gas or oil. Heat generating electrodes can also be in serted directly into the baths.
  • Example 2 Test pieces of a highly alloy chromesteel identified as workpiece numbers 4006 to 4021 were heat rolled and annealed in the atmosphere whereupon oxide scales appeared on the surface of the test pieces. The surface of some of the test pieces were then treated for 5 to 10 sec. at 500 C. in molten sodium hydroxide 100 percent pure) and then for 5 to l seconds at 400 to 500 C(inmolten sodiummetal 100 percent pure). The surface of the thus treated metal pieces were clear of oxide scales.
  • the treatment required a pickling bath time of more than minutes in order to provide the same descaling effect as was provided by the process of the present invention. 18 percent Cr.
  • the metals which may be descaled in accordance with the present invention include alloyed and nonalloyed iron and steel as well as copper, alloys of zirkonium and titanium, iron free alloys basing on Ni, Co and Cr. g
  • the metals being processed in the process of the present invention may have any shape or configuration.
  • the process is particularly suitable to the treatment of objects which may be fed into themolten sodium metal bath in a continuous fashion, such as wire, cable, strips, bands, sheets, and similar elongated objects.
  • a metal object treating apparatus comprising, in combination, a first container, a bath of molten alkali metal hydroxide in said container suitable for pretreatment of the surface of said object, a second container open at the. top, a bath of molten sodium metal in said second container suitable for the treatment of the surface of said object after said baths in a molten state during said pretreatment and treatment, feeder means for feeding a metal object in and out of said baths, airtight housing means. and an inert atmosphere in said housing means over at least said bath of molten sodium metal and in contact therewith at said open top.
  • the molten alkali metal hydroxide bath being in contact with the molten sodium metal bath and sealing the bottom of saidsecond container, said molten sodium metal bath floating on said molten alkali metal hydroxide bath, heating means for maintaining both baths in a molten state, feeder means for feeding a metal object sequentially through saidvfirst bath, then through said second bath and again through said first bath, airtighthousing means, an inert atmosphere within said housing means, said opening of said wide top'of said second container disposed above the level of the molten alkali metal hydroxide in said first container'and extending into said inert atmosphere within the cross-sectional area of said airtight housing means whereby an inert atmosphere is maintained above said sodium metal.
  • An apparatus suitable for treating a metal object in a plurality of baths one of said baths. being a molten alkali metal tainer being positioned within, but out of contact with said pretreatment said second container having a narrow, open ,7

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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)
US706108A 1967-02-16 1968-02-16 Installation for the descaling of metals Expired - Lifetime US3552404A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DED0052292 1967-02-16
DED0053583 1967-07-13

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US3552404A true US3552404A (en) 1971-01-05

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US (1) US3552404A (de)
AT (1) AT293139B (de)
FR (1) FR1571367A (de)
GB (1) GB1205478A (de)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0071020A3 (de) * 1981-06-30 1985-12-27 Kabushiki Kaisha Toshiba Verfahren und Vorrichtung zum Entfernen von radioaktivem Material aus Gegenständen
US5113882A (en) * 1990-08-28 1992-05-19 Electrovert Ltd. Method of cleaning workpieces with a potentially flammable or explosive liquid and drying in the tunnel
US5246024A (en) * 1989-09-19 1993-09-21 Japan Field Company, Ltd. Cleaning device with a combustible solvent
US6016819A (en) * 1997-04-04 2000-01-25 Murray; Gordon High turbulence multiple stage wire pickling system
US6153015A (en) * 1996-05-10 2000-11-28 Metallgesellschaft Ag Process for removing soap-contaminated conversion layers on metal workpieces
US6340028B1 (en) * 1998-03-11 2002-01-22 Mitsubishi Heavy Industries, Ltd. Pickling device
US6530385B2 (en) * 1996-06-24 2003-03-11 Interuniversitair Microelektronica Centrum (Imec) Apparatus and method for wet cleaning or etching a flat substrate
US6630038B1 (en) * 1999-06-03 2003-10-07 Kabushiki Kaisha Toshiba Processing apparatus for forming metallic material
EP1672096A1 (de) * 2004-12-14 2006-06-21 Voest-Alpine Industrieanlagenbau GmbH & Co. Beizeinrichtung und Verfahren zum kontinuierlichen Beizen eines Metallbandes
US20060231123A1 (en) * 2002-10-18 2006-10-19 Nigel-Philip Cox Method for removing a layer area of a component
US20110079747A1 (en) * 2009-10-02 2011-04-07 Mcwhorter Edward Milton Direct current simplex generator

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2120278B (en) * 1982-05-14 1986-03-26 Rolls Royce Removing surface oxide layer
US4528043A (en) * 1982-05-14 1985-07-09 Rolls-Royce Limited Surface oxide layer treatment

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US876182A (en) * 1905-03-17 1908-01-07 James A Herrick Annealing-furnace.
US1595237A (en) * 1920-11-17 1926-08-10 Minton Ogden Method and apparatus for drying sheet material
US2134457A (en) * 1937-03-02 1938-10-25 Tainton Urlyn Clifton Metal treatment
US2390007A (en) * 1943-12-31 1945-11-27 Dominion Foundries & Steel Apparatus for continuously hot dip coating of tin on coiled strip
US2601863A (en) * 1948-04-06 1952-07-01 United States Steel Corp Method of cleaning hot-dip tin-plate
US2664901A (en) * 1947-05-09 1954-01-05 Gen Electric Quenching device
US3067758A (en) * 1962-04-03 1962-12-11 Seymour L Hersh Liquid actuated sealing means
US3129712A (en) * 1959-06-18 1964-04-21 Beteiligungsund Patentverwaltu Continuous scaling device for metal bands
US3293159A (en) * 1961-08-30 1966-12-20 Hooker Chemical Corp Process for producing a fused reducing bath for descaling
US3358980A (en) * 1965-01-21 1967-12-19 Inland Steel Co Apparatus for quenching web material
US3424614A (en) * 1963-02-28 1969-01-28 Schloemann Ag Cleaning,particularly de-scaling,of metal articles

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US876182A (en) * 1905-03-17 1908-01-07 James A Herrick Annealing-furnace.
US1595237A (en) * 1920-11-17 1926-08-10 Minton Ogden Method and apparatus for drying sheet material
US2134457A (en) * 1937-03-02 1938-10-25 Tainton Urlyn Clifton Metal treatment
US2390007A (en) * 1943-12-31 1945-11-27 Dominion Foundries & Steel Apparatus for continuously hot dip coating of tin on coiled strip
US2664901A (en) * 1947-05-09 1954-01-05 Gen Electric Quenching device
US2601863A (en) * 1948-04-06 1952-07-01 United States Steel Corp Method of cleaning hot-dip tin-plate
US3129712A (en) * 1959-06-18 1964-04-21 Beteiligungsund Patentverwaltu Continuous scaling device for metal bands
US3293159A (en) * 1961-08-30 1966-12-20 Hooker Chemical Corp Process for producing a fused reducing bath for descaling
US3067758A (en) * 1962-04-03 1962-12-11 Seymour L Hersh Liquid actuated sealing means
US3424614A (en) * 1963-02-28 1969-01-28 Schloemann Ag Cleaning,particularly de-scaling,of metal articles
US3358980A (en) * 1965-01-21 1967-12-19 Inland Steel Co Apparatus for quenching web material

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0071020A3 (de) * 1981-06-30 1985-12-27 Kabushiki Kaisha Toshiba Verfahren und Vorrichtung zum Entfernen von radioaktivem Material aus Gegenständen
US5246024A (en) * 1989-09-19 1993-09-21 Japan Field Company, Ltd. Cleaning device with a combustible solvent
US5113882A (en) * 1990-08-28 1992-05-19 Electrovert Ltd. Method of cleaning workpieces with a potentially flammable or explosive liquid and drying in the tunnel
US6153015A (en) * 1996-05-10 2000-11-28 Metallgesellschaft Ag Process for removing soap-contaminated conversion layers on metal workpieces
US6530385B2 (en) * 1996-06-24 2003-03-11 Interuniversitair Microelektronica Centrum (Imec) Apparatus and method for wet cleaning or etching a flat substrate
US20030145878A1 (en) * 1996-06-24 2003-08-07 Imec Vzw Apparatus and method for wet cleaning or etching a flat substrate
US6016819A (en) * 1997-04-04 2000-01-25 Murray; Gordon High turbulence multiple stage wire pickling system
US6340028B1 (en) * 1998-03-11 2002-01-22 Mitsubishi Heavy Industries, Ltd. Pickling device
US6630038B1 (en) * 1999-06-03 2003-10-07 Kabushiki Kaisha Toshiba Processing apparatus for forming metallic material
US20060231123A1 (en) * 2002-10-18 2006-10-19 Nigel-Philip Cox Method for removing a layer area of a component
EP1672096A1 (de) * 2004-12-14 2006-06-21 Voest-Alpine Industrieanlagenbau GmbH & Co. Beizeinrichtung und Verfahren zum kontinuierlichen Beizen eines Metallbandes
US20110079747A1 (en) * 2009-10-02 2011-04-07 Mcwhorter Edward Milton Direct current simplex generator

Also Published As

Publication number Publication date
FR1571367A (de) 1969-06-20
GB1205478A (en) 1970-09-16
AT293139B (de) 1971-09-27

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