US3466186A - Dip forming method - Google Patents

Dip forming method Download PDF

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Publication number
US3466186A
US3466186A US550237A US3466186DA US3466186A US 3466186 A US3466186 A US 3466186A US 550237 A US550237 A US 550237A US 3466186D A US3466186D A US 3466186DA US 3466186 A US3466186 A US 3466186A
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United States
Prior art keywords
crucible
rod
metal
temperature
casting
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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
US550237A
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English (en)
Inventor
Roland P Carreker Jr
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General Electric Co
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General Electric Co
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Publication date
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/008—Continuous casting of metals, i.e. casting in indefinite lengths of clad ingots, i.e. the molten metal being cast against a continuous strip forming part of the cast product
    • 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
    • C23C2/003—Apparatus
    • C23C2/0034—Details related to elements immersed in bath
    • 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
    • C23C2/003—Apparatus
    • C23C2/0036—Crucibles

Definitions

  • the baille has a plurality of openings at its lower end, and a feed inlet to the Crucible is positioned below the upper edge of the baille but above the openings in the baille. Molten metal introduced to the crucible flows downwardly between the Crucible walls and the baille and countercurrently within the baille.
  • My invention relates to an improvement in dip casting and particularly to a method and apparatus for eliminating the periodic formation of massive deposits of metal on a rod moving through a casting Crucible.
  • the present invention relates to another of the several aspects on which the successful operation of this invention of a commercial scale may be seen to depend.
  • Commercial operation requires, of course, that a Core rod be processed continuously through a casting Crucible and that the product formed have suilcient uniformity of properties and dimensions that it may be fed on a continuous basis through a variety of possible succeeding processing operations or stations depending on the nature of the product being formed and the conditioning or forming which may be needed to render it suitable for future use. From the above patents it will be appreciated that the product leaves the Crucible at a speed of about 200 linear feet per minute and that higher speeds are, of course, possible and contemplated.
  • a serious source of product irregularities in production operation of the dip ⁇ forming process is the periodic formation of bumps orbump like irregularities on the rod.
  • the bumps are adherent deposits of solid metal which may be the general form or shape of an asymmetrical protuberance and in the more pronounced cases tend to have radial symmetry and cover the entire 360 of the rod site where the deposit occurs.
  • the deposit ilares gradually outwardly in the downstream direction from the normal rod diameter to a maximum diameter and then curves sharply under to a relatively at bottom where the rod is against its normal diameter.
  • the shape is that of a bell.
  • the bells are deposited generally symmetrically to the ascending rods so that the rod forms a vertical axis extending through the Center of the bell.
  • defects in the product rod vary in size from the barely perceptible to more than double the normal diameter of the emerging rod.
  • the defects occur intermittently, depending apparently on prevailing Conditions, at intervals of one to many feet and sometimes almost periodically depending on other conditions.
  • One object of the present invention is to provide a method which substantially eliminates the deposit of excessive accretions on a dip formed rod.
  • Another object is to provide an apparatus which is effective in minimizing the occurrence of irregular accretions on dip formed rod products.
  • the objects of the present invention may -be carried out by channeling the flow of liquid metal in the casting Crucible 'to minimize the tendency of liquid metal proximate the entry port to freeze.
  • the objects may be achieved by providing an annular llow baille in the casting Crucible, said baille cooperating with the inner Crucible walls and providing an axially inward flow of metal in Contact with the lower wall of said Crucible toward the entrance to said Crucible.
  • FIGURE 1 is an axial vertical section of a Casting Crucible as used in dip Casting of metals.
  • FIGURE 2 is an elevation of a rod on which an oversize bell has deposited in a casting Crucible such as illustrated in FIGURE 1.
  • FIGURE 3 is an axial vertical section taken along the line 3--3 of FIGURE 4 and similar to that shown in FIGURE 1 but differing in that it illustrates the incorporation of the flow baille of the present invention.
  • FIGURE 4 is a horizontal section taken along the line 4-4 of FIGURE 3 and illustrating the positioning of the use of the fiow baille of the present invention.
  • the rod 10 on which metal is to be accreted is surface cleaned and fed to the Crucible entrance 14 by means not shown but now known in the art as pointed out above.
  • the rod 10 enters the bottom entrance 14 of a dip casting Crucible 12 under vacuum produced also by means not shown but now well known in the art as pointed out above.
  • the rod 10 enters the Crucible 12 through entrance port 14 in the nozzle 16.
  • the dimensions of the nozzle 16 in relation to the entering rod and the temperature at which the nozzle is maintained is critical for successful efficient operation of the process.
  • the basis for this criticality is essentially as follows.
  • a bath of molten metal is maintained at a depth sufficient to permit a metal rod entering from port 14 Ito remain in contact with the metal for a time designated conveniently as a residence time.
  • the residence time obviously depends on the depth of the bath 18 and on the linear rate of movement of the rod 10. Increasing rates ofl rod movement require greater depths of molten metal to provide the same residence time of a unit segment of the rod in the bath.
  • the way in which a leakage at this point can be avoided, and a metal nozzle insert provided without such leakage at this point, is by maintaining a temperature differential lengthwise of the nozzle so that the internal end is above the melting point of liquid and the outer end is below the melting point of the liquid metal. With this temperature differential the outflow of liquid metal is prevented by the solidication of the metal which ows into the potential flow paths between the graphite crucible and the molybdenum insert.
  • the use of the nozzle insert is essential to provide a surface which will not be worn or abraded as the surface of graphite would be by the rapidly moving -metal core rod entering the liquid metal bath.
  • a molybdenum nozzle inser-t has been found satisfactory for this purpose and is effective in permitting high velocity entry of copper rod to the copper melt in the crucible on a continuous basis.
  • the present inventor has recognized that the origin of the bumps, bells and other surface irregularities on the rod product of the dip casting process may be the result of the need for maintaining the close balance of temperature in a crucible in which a very rapid heat exchange process is taking place.
  • the high rate of heat exchange is evident from the fact -that metal is cast at a rate of more than two hundred pounds per minute from a crucible having a melt depth of about fifteen inches and a diameter of 6 inches.
  • Use of increased insulation at the crucible bottom is also useful but does not reduce the large central heat leak which resultsfrom the movement of the core rod through any insulation wall and into the melt.
  • Increasing rod temperature also has the effect of reducing the overall efficiency of the casting in reducing the amount of metal which can accrete on a rod of given composition and dimensions.
  • the supply of liquid metal is through a graphite tube from a source not shown. Heat may be supplied by means of an induction heating coil 22.
  • the crucible is also provided with a lid 26 to assist in temperature and atmosphere control.
  • the rod 10 enlarged by the accretion of metal, emerges through the exit port 28.
  • FIGURE 2 an elevational View is provided illustra-ting the form of a severe bell.
  • FIGURE 3 The elements described with reference to FIGURE 1 above are duplicated in FIGURE 3, the like reference numerals indicating like parts but the numerals being distinguished in FIGURE 3 by the addition of a prime.
  • the first is the annular bathe element 30 and the second is the baffle spacer 32.
  • the annular baffle is shown disposed generally concentrically to the crucible walls and to the rod 10 passing through the melt. It will be evident from the description which follows that the concentricity, while important in certain applications, may be modified in others, particularly for example with reference to casting onto rods of different cross section or on to sheet or other stock of irregular cross section.
  • the baffle 30 has radially extending slots 34 at its lower ends which, when the bafe is in place in the crucible with its slotted end against the lower internal surface of the crucible, form radially extending channels for ow of the liquid metal fromthe outer annular reservoir 36 to the inner annular reservoir 38.
  • the arrangement of the crucible melt into two generally concentric annular flow paths provides a generally countercurrent flow of liquid metal.
  • this arrangement rather than reducing or eliminating temperature gradients in the casting crucible, can have the effect of increasing such gradients.
  • This capability of the apparatus of the present invention to increase the efficiency of operation of the casting process is dependent on the discovery that while the generation of temperature gradients can have a deleterious effect on processing efhciency as explained above, it is possible to so arrange the liquid metal flow that the existence of temperature gradients can actually add efficiency to the processing.
  • a heat source such as induction heating coil 22 will provide a delivery of heat at the inner surface of the outer Crucible wall.
  • liquid metal of lower temperature entering the Crucible 12 from supply tube 24' will accept heat from the Crucible wall inasmuch as the iiow of ⁇ metal is conned by the architect 30 to an outer annular ow path in the Crucible.
  • the metal must leave the outer annular ow path at a minimum temperature controlled in part by its temperature on entering the outer annular flow path and in part on the temperature of the outer Crucible wall which partially denes the outer annular path.
  • a temperature gradient which extends along the inner of the two interconnected annular columns of liquid metal can be advantageous in bringing the temperature of this column closer to the casting temperature without risk of the formation of surface irregularities such as the bumps and bells described above.
  • a significant secondary advantage of establishing and maintaining throughout operation the two interconnected annular columns of liquid metal by means such as bafe 30 is that metal bath 18 is continuously skimmed. Thus, foreign matter such as pieces of refractory and slag entrained in the liquid metal entering Crucible 12 through supply -tube 24', being lighter than the liquid metal, is blocked from access to the liquid metal column within baffle 30 and collects in the upper portion of the column of liquid metal surrounding bafe 30.
  • a method of accreting metal onto a core rod comprising passing said rod through a molten bath of metal contained in a Crucible to accrete metal thereon and removing the resulting cast rod from said crucible, the improvement comprising: (a) establishing in said Crucible an interior melt zone through which said rod passes and a substantially concentrically disposed exterior melt zone provided by an annular balile having a plurality of openings at its lower end for establishing Communication be tween said zones, (b) continuously introducing molten metal to the upper part of said exterior zone to substantially fill both of said zones of said crucible, (c) establishing a downward flow of molten metal in ⁇ said exterior melt zone and a countercurrent ⁇ upward flow of molten metal in said interior melt Zone, (d) supplying heat to the outer surface of said exterior zone to maintain the temperature thereof above a minimum and withdrawing heat from the interior zone, and (e) inducing iiow of molten metal between said zones at least partially by the removal of substantially solid metal from

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)
  • Coating With Molten Metal (AREA)
US550237A 1966-05-16 1966-05-16 Dip forming method Expired - Lifetime US3466186A (en)

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Application Number Priority Date Filing Date Title
US55023766A 1966-05-16 1966-05-16

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US (1) US3466186A (de)
DE (1) DE1558253C2 (de)
GB (1) GB1186592A (de)
SE (1) SE307629B (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5187129A (en) * 1974-12-20 1976-07-30 Gen Electric Renzokuchuzohoho oyobisochi
DE4426705C1 (de) * 1994-07-20 1995-09-07 Mannesmann Ag Inversionsgießeinrichtung mit Kristallisator
US6037011A (en) * 1997-11-04 2000-03-14 Inland Steel Company Hot dip coating employing a plug of chilled coating metal
US20090272319A1 (en) * 2005-07-01 2009-11-05 Holger Behrens Apparatus For Hot-Dip Coating Of A Metal Strand
CN110560668A (zh) * 2019-09-10 2019-12-13 清华大学天津高端装备研究院洛阳先进制造产业研发基地 陶瓷空心球/金属基复合泡沫材料的重力铸造方法及设备

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9911006D0 (en) 1999-05-13 1999-07-14 Rolls Royce Plc A titanium article having a protective coating and a method of applying a protective coating to a titanium article

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1426683A (en) * 1920-04-29 1922-08-22 Stalhane Otto Process for coating metal cbjects with a layer of another metal
US1589329A (en) * 1925-11-20 1926-06-15 Eastman Kodak Co Process of electrodepositing rubber upon a metal wire
US2072060A (en) * 1936-08-13 1937-02-23 Metalloys Company Wire coating process and apparatus
US2123894A (en) * 1935-08-21 1938-07-19 Clarence W Hazelett Method of producing hollow metallic shapes and apparatus therefor
US2127413A (en) * 1934-11-05 1938-08-16 Goodrich Co B F Method and apparatus for coating strip material
US2231142A (en) * 1940-05-15 1941-02-11 Metalloys Company Wire coating apparatus
US2543936A (en) * 1947-09-22 1951-03-06 Julian L Reynolds Apparatus for covering a metallic core with a cast layer of another metal
US2702525A (en) * 1949-07-13 1955-02-22 Whitfield & Sheshunoff Inc Apparatus for coating wire or strip with molten aluminum

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE866079C (de) * 1941-10-30 1953-02-05 Thyssen Huette Ag Vorrichtung zum ununterbrochenen Giessen von Straengen aus Stahl unter Benutzung eines Bleibades
GB1083491A (en) * 1964-05-14 1967-09-13 Davy & United Eng Co Ltd Continuous casting

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1426683A (en) * 1920-04-29 1922-08-22 Stalhane Otto Process for coating metal cbjects with a layer of another metal
US1589329A (en) * 1925-11-20 1926-06-15 Eastman Kodak Co Process of electrodepositing rubber upon a metal wire
US2127413A (en) * 1934-11-05 1938-08-16 Goodrich Co B F Method and apparatus for coating strip material
US2123894A (en) * 1935-08-21 1938-07-19 Clarence W Hazelett Method of producing hollow metallic shapes and apparatus therefor
US2072060A (en) * 1936-08-13 1937-02-23 Metalloys Company Wire coating process and apparatus
US2231142A (en) * 1940-05-15 1941-02-11 Metalloys Company Wire coating apparatus
US2543936A (en) * 1947-09-22 1951-03-06 Julian L Reynolds Apparatus for covering a metallic core with a cast layer of another metal
US2702525A (en) * 1949-07-13 1955-02-22 Whitfield & Sheshunoff Inc Apparatus for coating wire or strip with molten aluminum

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5187129A (en) * 1974-12-20 1976-07-30 Gen Electric Renzokuchuzohoho oyobisochi
JPS543644B2 (de) * 1974-12-20 1979-02-26
DE4426705C1 (de) * 1994-07-20 1995-09-07 Mannesmann Ag Inversionsgießeinrichtung mit Kristallisator
US6037011A (en) * 1997-11-04 2000-03-14 Inland Steel Company Hot dip coating employing a plug of chilled coating metal
US20090272319A1 (en) * 2005-07-01 2009-11-05 Holger Behrens Apparatus For Hot-Dip Coating Of A Metal Strand
CN110560668A (zh) * 2019-09-10 2019-12-13 清华大学天津高端装备研究院洛阳先进制造产业研发基地 陶瓷空心球/金属基复合泡沫材料的重力铸造方法及设备

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Publication number Publication date
DE1558253C2 (de) 1974-01-03
SE307629B (de) 1969-01-13
GB1186592A (en) 1970-04-02
DE1558253B1 (de) 1973-03-22

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