US3523815A - Method for producing a uniform metallic coating on wire - Google Patents

Method for producing a uniform metallic coating on wire Download PDF

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Publication number
US3523815A
US3523815A US695097A US3523815DA US3523815A US 3523815 A US3523815 A US 3523815A US 695097 A US695097 A US 695097A US 3523815D A US3523815D A US 3523815DA US 3523815 A US3523815 A US 3523815A
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Prior art keywords
wire
coating
die
metal
molten
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Expired - Lifetime
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US695097A
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English (en)
Inventor
Lawson J Baxter
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Wire Rope Corp of America Inc
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Armco Inc
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Assigned to WIRE ROPE CORPORATION OF AMERICA, INCORPORATED, A CT CORP. reassignment WIRE ROPE CORPORATION OF AMERICA, INCORPORATED, A CT CORP. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: ARMCO INC.
Assigned to WIRE ROPE CORPORATION OF AMERICA, INCORPORATED reassignment WIRE ROPE CORPORATION OF AMERICA, INCORPORATED SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: WIRE ROPE CORPORATION OF AMERICA, INCORPORATED
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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
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
    • C23C2/36—Elongated material
    • C23C2/38—Wires; Tubes
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
    • G09B19/00—Teaching not covered by other main groups of this subclass
    • G09B19/02—Counting; Calculating

Definitions

  • this invention relates to a continuous process wherein the wire passes upwardly through the bath of molten coating metal in a substantially vertical path of travel.
  • a vertical mode of operation has the obvious advantage that during the period immediately after emerging from the coating bath, the force of gravity acting on the still liquid metallic coating does not tend to destroy concentricity.
  • the art has had great problems in the production of intermediate and heavy weight metallic coatings using such a vertical process.
  • U.S. Pats. 2,914,423 and 3,060,889 are directed in part to a method and apparatus for improving the surface characteristic of a metallic coated wire.
  • Both of these references include the provision of an exit die through which the wire passes after emerging from the metallic coating bath. This exit die is completely above the normal level of the coating metal in the bath so that the moving wire Will pull up the molten coating metal to the die forming an oxide sock, while the substantially pure metal under the oxide layer is withdrawn as a coating on the wire. While this method is satisfactory for the production of light coating weights,
  • this invention contemplates that the exit die through which the wire is vertically withdrawn from the coating bath be substantially submerged in the molten coating metal. As the wire enveloped by a still liquid coating emerges from the exit die, a non-oxidizing gas is blown against it at low pressure.
  • the weight of coating material applied to the wire including such factors as speed of wire passage, temperature of the Wire prior to immersion, temperature of the coating bath, diameter of the wire, amount of clearance between the surface of the wire and the exit die, and possibly others.
  • the primary factor in terms of controlling coating Weights within the limits of this application is the relative level between the top surface of the exit die and the level of molten metal in the coating bath. That is, the level of molten coating metal must be substantially at or just below the top surface of the exit die. If the molten metal level gets much above the upper die surface, the rough coating characteristic of the free exit method described above will result. Also, if the bath level gets below the upper die surface by more than a predetermined amount, the consistently maintainable coating weights would be too light.
  • FIG. 1 is a cross sectional view showing a coating compartment according to this invention.
  • FIG. 2 is an end elevational view of the apparatus shown in FIG. 1 as seen from the right.
  • FIG. 3 is a top plan view of the apparatus of FIG. 1.
  • FIG. 4 is a perspective view of the die element.
  • the hot dip coating of steel wire includes the steps of thoroughly cleaning or otherwise preparing the surface of the wire for the reception of a molten metal coating. While these preparatory steps do not per se form a part of this invention, it will be understood that the invention contemplates such a pretreatment prior to the time the wire arrives at the molten coating bath.
  • alkali or other chemical cleaning involving wetting and drying of the strip surface, or even abrasive treatment may be used, so long as the surface of the wire is sufiiciently cleaned that an extremely rapid and thorough wetting by the molten metal itself takes place in the coating bath.
  • FIG. 1 one form of apparatus for practicing the teachings of this invention has been shown.
  • the wire to be coated is indicated at 10, and as already indicated, it is to be assumed that the surface of the wire has been adequately prepared to make it receptive to the molten coating metal.
  • the tube 12 is a schematic representation of the hood providing a protective atmosphere for the wire between the time it leaves the reducing furnace and the time it enters the coating bath. It will be understood that this tube Will be supplied by conventional means with a suitable protective atmosphere.
  • the bath of molten coating metal will be maintained within the body portion of the apparatus indicated generally at 14. As seen in the drawings, the body portion is provided with the substantially vertical passage 16, and with the passage 18 which is arranged substantially normal to the passage 16. As will be explained in more detail presently, the intersection of these two passages defines the bath of molten coating metal.
  • the die element Snugly maintained within the vertical passage 16 is the die element indicated generally at 20, and shown in perspective in FIG. 4.
  • the die element is provided with a horizontal passage 22, and with an intersecting vertical passage indicated generally at 24.
  • the passage 24 includes the lower and upper passages respectively indicated at 24a and 24b.
  • the die element 20 is received in the passage 16 of the body portion 14, and the passages 18 and 22 of the body portion and die element respectively are aligned.
  • the wire to be coated passes upwardly through the vertical passages 24a and 24b in the die element.
  • the die element 20 should be formed of a very finegrained material which may be given a very smooth bore in order to obtain a good finish on the coating.
  • the material selected should be non-wettable by the molten coating metal and have good wear resistance. Ceramic materials such as Diamondite and Refrax has been found commercially satisfactory. Carbides having the desired properties may also be used.
  • this member Disposed in the passage 16 of the body portion just above the die element 20 is the member indicated generally at 26. As is clearly shown in FIG. 1, this member includes a portion 26a of reduced diameter, which in conjunction with the walls of the passage 16 forms the plenum chamber 28.
  • the reduced diameter portion 26a of the member 26 is provided with a plurality of radial apertures 30. In the embodiment shown, these apertures are arranged substantially normal to the wire 10, but it is to be understood that this arrangement is not limiting. That is, under certain circumstances, the apertures should be arranged obliquely to the wire axis. In this connection, reference is made to US. Pat. No. 3,060,889, in the name of Earle L.
  • Knapp which discloses a swirl imparting gas finishing nozzle which may be used in connection with this invention.
  • the body portion 14 is provided with the passageway 32. One end of this passage communicates with the plenum chamber 28, and the other end, via the tube 34, is in communication with a supply of finishing gas.
  • the hold down cap 36 held against the top surface of the member 26 is the hold down cap 36. It will be seen that the circular hold down cap is held in place by means of the wedges 38 4 which pass under the hold down brackets 40 and 42 of the body portion 14, and serves to prevent movement of the die element 20 and member 26 due to the wire movement therethrough.
  • the entire assembly may be moved vertically in relation to the trough 44, or the die element 20 may be adjusted vertically within the body portion 14, in order to vary the level of the coating metal in the die.
  • the trough 44 will be continuously supplied with molten coating metal to the level indicated by the line 46.
  • the relationship between the level of molten metal in the trough 44 and the top surface of the die element 20 is a very important facet of this invention, and will be discussed in more detail presently.
  • the aligned passages 18 and 22 will in effect define a reservoir of molten coating metal through which the wire 10 is drawn.
  • the horizontal passage 22 in effect divides the die element 20 into an entrance die portion 48 having passage 24a and an exit die portion 50 having passage 24b between which the coating bath is maintained.
  • the wire 10 with a properly prepared surface passes from the protective atmosphere inside the tube 12, through the entrance die 48 and into the bath of molten coating metal. It emerges from the coating bath through the exit die 50, and is immediately contacted by the finishing gas through the apertures 30.
  • a non-oxidizing gas such as hydrogen under a relatively low pressure. Such a gas retards oxidation of the still molten coating metal and, under some circumstances, has a slight effect upon coating weight.
  • the entrance passage 24a be up to 0.10" smaller in diameter than the exit die passage 24b. This prevents the coated wire from rubbing on the wall of the exit die. Thus, a uniform coating is Withdrawn around the strand periphery.
  • Exemplary exit die clearances over the base wire diameter are as follows:
  • a clearance of .010" to .040" on the diameter, preferably .015" to .025" should be maintained. If the clearance is too small, the coating metal will not feed uniformly with sufficient volume. If the clearance is too large, excess metal will accumulate in globular form on the top surface of the exit die and around the strands, choking off the apertures 30.
  • the principle of applying 0.40 oz. minimum coating to a wire strand involves pulling enough liquid metal into the clearance space between the strand surface and the exit die wall to form a controllable meniscus. This is stabilized at a level near the top surface of the exit die by a combination of Wire speed Which promotes metal pumping action, die clearance, smoothness of the exit die bore wall, length of the exit bore, hydrostatic head of the melt supply in respect to the top surface of the exit die, fluidity of the coating metal, the downward or lateral pressure of the finishing gas jets, and the rate of aluminum oxidation on the top surface of the meniscus.
  • the exit die bore length has been designed at for wear life. This length can be more or less depending on die material.
  • the length of the entrance die is also This permits turning a worn die end for end to ream out to a next larger wire size.
  • the fluidity of the coating metal within the exit die is controlled by the temperature of the passing strand and of the melt supply.
  • Wire temperatures of 1240 to 1270 F. are preferred. Lower values will cause an increase in wire coating weight. Higher temperatures tend to form excessive oxide crusts on the top side of the exit die. Wire temperatures in the order of 1350 F. and higher will cause the coating weight to be less. These figures refer to high purity aluminum that melts at about 1220 F. Undoubtedly, both temperature ranges would shift in relation to the melting point of coating metal.
  • the temperature of the aluminum coating metal bath is not highly critical. A temperature between 1250 F. and 1300 F. has been found adequate. The preferred range is on the order of 1270 F. to 1280 F., but it is believed that satisfactory results may -be achieved with a temperature ranging from the 1220 F. melting point of aluminum to as much as 1500 F.
  • wire speed has been found to have very little effect on coating weights. While the evidence is not clear, it appears that faster wire speeds bring about a smoother and more brilliant surface to the coating applied. Thus, commercial operations in excess of 50 feet per minute are to be preferred.
  • the relative levels of the coating metal are determined under static conditions preliminary to feeding the wire.
  • the desired coating weight dictates the height at which the entire coating assembly is positioned relative to the top surface of the metal in the trough (line 46 in FIG. 1).
  • the coating device herein described is capable of applying high purity aluminum coating (99.75% purity in the outer coating layer) in the weight ranges of 0.30 oz. class (0.20 oz. minimum), 0.50 oz. class (0.40 oz. minimum), and 0.80 oz. class (0.70 oz. minimum).
  • the level of molten coating metal in the supply may vary from a height approximately below the level of the top surface of the exit die to a height approximately /8" above the level of the top surface of the exit die.
  • molten aluminum around a rising coated wire strand will form a concave meniscus. Therefore, even though the indicated static level of molten metal is above the top surface of the exit die, the meniscus is kept from expanding over the top surface of the die by controlling the impingement of the finishing gas. Under no circumstances can the molten coating metal be permitted to flow over the top surface of the exit die.
  • a wire coating method including the steps of thoroughly cleaning the surface of said wire, raising the temperature of said wire surface, and passing said wire through a bath of molten coating metal so that it emerges in a vertical path
  • the improved method comprising the steps of providing an exit die having an aperture at least partially submerged in said bath, said aperture having a clearance over said wire of about .010 inch to about .040 inch on the diameter, withdrawing said wire through said aperture without further contacting said molten coating metal, and controlling the level of molten metal in said bath with respect to the top surface of said die so that said level is substantially at said top surface of said die whereby to control the thickness of coating metal applied to said wire.
  • a wire coating method including the steps of thoroughly cleaning the surface of said wire, raising the temperature of said wire surface, and passing said wire through a bath of molten coating metal so that it emerges in a vertical path of travel through an exit die having a clearance over said wire of about .010 inch to about .040 inch on the diameter, and without further contacting said molten coating metal; the improved method of controlling coating thickness comprising the step of maintaining the level of molten coating metal in the bath not more than about 7 inch below and not more than about A; inch above the top surface of said die.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Business, Economics & Management (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Entrepreneurship & Innovation (AREA)
  • Physics & Mathematics (AREA)
  • Educational Administration (AREA)
  • Educational Technology (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Coating With Molten Metal (AREA)
US695097A 1968-01-02 1968-01-02 Method for producing a uniform metallic coating on wire Expired - Lifetime US3523815A (en)

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US69509768A 1968-01-02 1968-01-02

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US (1) US3523815A (ru)
BE (1) BE726335A (ru)
DE (1) DE1900019A1 (ru)
ES (1) ES362056A1 (ru)
FR (1) FR1596958A (ru)
GB (1) GB1237947A (ru)
NL (1) NL6818506A (ru)
SU (1) SU436500A3 (ru)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3779056A (en) * 1971-12-28 1973-12-18 Bethlehem Steel Corp Method of coating steel wire with aluminum
DE2733075A1 (de) * 1976-07-20 1978-04-13 Battelle Memorial Institute Verfahren zum ueberziehen eines drahtfoermigen gegenstandes mit einem thermisch schmelzbaren material
US4339480A (en) * 1980-04-11 1982-07-13 Bethlehem Steel Corporation Gas wiping apparatus and method of using

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4155235A (en) * 1977-07-13 1979-05-22 Armco Steel Corporation Production of heavy pure aluminum coatings on small diameter tubing
JPH0679449B2 (ja) * 1982-12-24 1994-10-05 住友電気工業株式会社 耐熱亜鉛被覆ａｃｓｒ用鉄合金線
JPH11505885A (ja) * 1995-05-29 1999-05-25 エム３デー，ソシエテ アノニム ストリップを形成する材料よりも低い融点または液相点を有する金属または合金で金属ストリップを被膜する方法及び装置
RU169999U1 (ru) * 2016-07-04 2017-04-11 Федеральное государственное бюджетное образовательное учреждение высшего образования "Магнитогорский государственный технический университет им. Г.И. Носова" Устройство для нанесения покрытия на изделие

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1496309A (en) * 1921-12-31 1924-06-03 Harvey F Girvin Process and apparatus for coating metal articles
US2166250A (en) * 1936-04-02 1939-07-18 Joseph L Herman Method of coating metallic materials
US2702525A (en) * 1949-07-13 1955-02-22 Whitfield & Sheshunoff Inc Apparatus for coating wire or strip with molten aluminum
US2914423A (en) * 1955-05-12 1959-11-24 Armco Steel Corp Method and apparatus for metallic coating of metallic strands
GB972527A (en) * 1962-08-10 1964-10-14 Marshall George Whitfield Improvements in or relating to the coating of metals with other metals
US3227577A (en) * 1962-09-18 1966-01-04 Colorado Fuel & Iron Corp Metal coating of long lengths of metal bodies
GB1030967A (en) * 1964-02-18 1966-05-25 British Insulated Callenders Improvements in or relating to methods of and apparatus for coating wires with metal
US3330690A (en) * 1962-12-13 1967-07-11 Armco Steel Corp Production of heavy metallic coatings on metallic strands

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1496309A (en) * 1921-12-31 1924-06-03 Harvey F Girvin Process and apparatus for coating metal articles
US2166250A (en) * 1936-04-02 1939-07-18 Joseph L Herman Method of coating metallic materials
US2702525A (en) * 1949-07-13 1955-02-22 Whitfield & Sheshunoff Inc Apparatus for coating wire or strip with molten aluminum
US2914423A (en) * 1955-05-12 1959-11-24 Armco Steel Corp Method and apparatus for metallic coating of metallic strands
GB972527A (en) * 1962-08-10 1964-10-14 Marshall George Whitfield Improvements in or relating to the coating of metals with other metals
US3227577A (en) * 1962-09-18 1966-01-04 Colorado Fuel & Iron Corp Metal coating of long lengths of metal bodies
US3330690A (en) * 1962-12-13 1967-07-11 Armco Steel Corp Production of heavy metallic coatings on metallic strands
GB1030967A (en) * 1964-02-18 1966-05-25 British Insulated Callenders Improvements in or relating to methods of and apparatus for coating wires with metal

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3779056A (en) * 1971-12-28 1973-12-18 Bethlehem Steel Corp Method of coating steel wire with aluminum
DE2733075A1 (de) * 1976-07-20 1978-04-13 Battelle Memorial Institute Verfahren zum ueberziehen eines drahtfoermigen gegenstandes mit einem thermisch schmelzbaren material
US4169426A (en) * 1976-07-20 1979-10-02 Battelle Memorial Institute Apparatus for coating a filiform element
US4339480A (en) * 1980-04-11 1982-07-13 Bethlehem Steel Corporation Gas wiping apparatus and method of using

Also Published As

Publication number Publication date
ES362056A1 (es) 1970-11-01
NL6818506A (ru) 1969-07-04
FR1596958A (ru) 1970-06-22
SU436500A3 (ru) 1974-07-15
DE1900019A1 (de) 1969-07-31
BE726335A (ru) 1969-05-29
GB1237947A (ru) 1971-07-07

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AS Assignment

Owner name: WIRE ROPE CORPORATION OF AMERICA, INCORPORATED, A

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ARMCO INC.;REEL/FRAME:004860/0649

Effective date: 19880314

Owner name: WIRE ROPE CORPORATION OF AMERICA, INCORPORATED, 60

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ARMCO INC.;REEL/FRAME:004860/0649

Effective date: 19880314

AS Assignment

Owner name: WIRE ROPE CORPORATION OF AMERICA, INCORPORATED

Free format text: SECURITY INTEREST;ASSIGNOR:WIRE ROPE CORPORATION OF AMERICA, INCORPORATED;REEL/FRAME:005029/0103

Effective date: 19881014