US3554511A - E furnace - Google Patents

E furnace Download PDF

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Publication number
US3554511A
US3554511A US790578A US3554511DA US3554511A US 3554511 A US3554511 A US 3554511A US 790578 A US790578 A US 790578A US 3554511D A US3554511D A US 3554511DA US 3554511 A US3554511 A US 3554511A
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US
United States
Prior art keywords
trough
base
sheath
outer peripheral
inner peripheral
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
US790578A
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English (en)
Inventor
Herbert Wald
Harold K Young
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Bethlehem Steel Corp
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Bethlehem Steel Corp
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Publication date
Application filed by Bethlehem Steel Corp filed Critical Bethlehem Steel Corp
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Publication of US3554511A publication Critical patent/US3554511A/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B11/00—Bell-type furnaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/663—Bell-type furnaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/663—Bell-type furnaces
    • C21D9/673—Details, accessories, or equipment peculiar to bell-type furnaces
    • 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
    • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
    • C23C10/06—Solid state diffusion of only metal elements or silicon into metallic material surfaces using gases
    • C23C10/08—Solid state diffusion of only metal elements or silicon into metallic material surfaces using gases only one element being diffused
    • C23C10/10—Chromising
    • 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
    • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
    • C23C10/28—Solid state diffusion of only metal elements or silicon into metallic material surfaces using solids, e.g. powders, pastes
    • C23C10/30—Solid state diffusion of only metal elements or silicon into metallic material surfaces using solids, e.g. powders, pastes using a layer of powder or paste on the surface
    • C23C10/32—Chromising

Definitions

  • ABSTRACT An improved bell-type furnace which includes a base and a removable inner cover that rests on the base and forms with it an enclosed heating chamber.
  • the base has an outer peripheral sealing trough which receives the lower end of the inner cover and acts to prevent the escape of gas which is circulated in the heating chamber.
  • the gas is delivered to and discharged from the heating chamber by means of gas inlet and discharge pipes which extend into the base inner cover peripheral sealing trough.
  • the base also includes a refractory pedestal which is enclosed by a gastight sheath.
  • the sheath includes a bottom plate, an outer peripheral sidewall having an outer peripheral sealing trough adjacent its upper end, and an inner peripheral sidewall having an inner peripheral sealing trough adjacent its upper end.
  • the sheath further includes a top plate which has downwardly projecting outer and inner peripheral flanges that extend into the sheath outer and inner peripheral troughs. Lead, liquid at furnace operating temperatures, in the sheath troughs seals between them and the flanges of the top plate.
  • This invention relates to bell-type furnaces for annealing and/or chromizing of metal products and more particularly to an improved base and inner cover for such a furnace.
  • Bell-type furnaces generally comprise a base upon which the metal, usually in coil form, is stacked, a removable inner cover which sets on the base and'forms with it a heating chamber, and a refractory lined outer cover that is disposed over the inner cover.
  • Heating units in'the. outer cover furnish heat for the'chamber.
  • a gaseous atmosphere is piped to the heating chamber where it is circulated by means of a fan mounted in the base.
  • means are' provided to seal between the base and the inner cover.
  • the gaseous atmosphere supplied to the heating chamber during an annealing cycle is nonreactive while during at least a portion of a chromizing cycle the gaseous atmosphere supplied is reactive and contains chlorine.
  • the chlorine-containing reactive gaseous atmosphere is corrosive and to prevent its infiltration into the furnace base, the base is provided with a gastight sheath that forms a chamberand surrounds a porous cast refractory pedestal. The elements of the sheath are joined and sealed by welding to protect against such infiltration.
  • a'nonreactive sealing gas is piped into the sheath chamber to pressurize it.
  • a bell-type furnace base comprises a bottom plate, a refractory pedestal, and a top plate, all of annular shape.
  • Outer and inner peripheral side plates extend between the bottom andtop plates and form a chamber which is occupied by the refractory pedestal.
  • Extending across the opening in the bottom plate and bolted to it is the fan which circulates the gaseous atmosphere in the heating chamber.
  • a trough extending around the outer periphery of the base is adapted to hold sealing means and to receive the lower end of the inner cover which extends downwardly into the sealing means.
  • a number of conduits, including the gaseous atmosphere gas inlet and discharge pipes and thermocouple conduits, extend through the baseand are welded to its top and bottom plates.
  • the temperature within the inner cover of a bell-type furnace during an annealing cycle reachessimple 1200l400 F. and during a chromizing cycle thetemperature rises as high as about 1750 F. Alternate heating and cooling of the furnace causes considerable expansion and contraction of the base top plate. Such expansion and contraction of the top plate requires that the gaseous atmosphere inlet and discharge pipes and thermocouple conduits be fabricated with liquid metal seals which allow these members to shift position to a limited extent.
  • portions of the base are fabricated of a metal, such as lnconel, (T.M.) having high strength at elevated temperatures.
  • Another object of this invention is to provide an improved bell-type furnace base which has gaseous atmosphere inlet and discharge pipes that do notpass through the base top plate.
  • a further object of this invention is to provide a bell-type furnace base sheath which is gastight and has a top plate that is not rigidly connected to other sheath elements so that it is able to expand and contract with relative freedom.
  • a bell-type furnace with a base that has the gaseous atmosphere inlet and discharge pipes extending through the base outer peripheral sealing trough.
  • the base refractory pedestal is enclosed by a gastight sheath.
  • the sheath includes outer and inner peripheral troughs adjacent the upper ends of the sheath outer and inner sidewalls and means to seal between the outer sidewalland the outertrough and the inner sidewall and the inner trough.
  • the base sheath top plate has outer and inner peripheral flanges which project downwardly into the outer and inner sheath troughs which contain means to seal between the top plate flanges and the troughs.
  • FIG. 1 is a vertical sectional view through a portion of a bell-type furnace embodying the present invention.
  • FIG. 2 is an enlarged plan section, taken on the line 2-2 of FIG. 1, illustrating the lower end of the removable inner cover, the base outer peripheral trough, and the gas inlet pipe of the furnace of FIG. 1.
  • FIG. 3 is a cross-sectional view taken on the line3-3 of FIG. 2.
  • FIG. 4 is an enlarged detail view of a portion of the furnace of FIG. 1 illustrating one manner of sealing between a base sheath sidewall, sealing trough, and flanged top plate.
  • FIG. 5 is an enlarged detail view of a portion of furnace of FIG. 1 illustrating an alternate manner of sealing between a base sheath sidewall, sealing trough, and top plate.
  • FIG. 1 a portion of a bell-type furnace 10 having base 11 and removable inner cover 12 which forms heating chamber 13 with the base.
  • the base comprises a supporting framework 14, outer peripheral trough 15,.annular refractory pedestal 16, sheath 17 forming chamber 60 and enclosing the pedestal, and core section 18.
  • Core section 18 is provided with a central-vertically extending sleeve 19 and comprises an annular cooling chamber 20,
  • Removable cover 12 has its lower end 33 extending into sealing means 30 in trough 15. Spaced from inner cover lower end 33 and on opposite sides of the cover are gas inlet and discharge openings 34 and 35 respectively, which cooperate with gaseous atmosphere inlet and discharge pipes, 31 and 32, respectively, in trough 15. Gas inlet anddischarge enclosures 36 and 36', respectively, each having an open bottom, extend outwardly from the lower end 33 of the inner cover and downwardly from around openings 34 and 35, respectively. Each enclosure comprises a top plate 37, side plates 38, and outer plate 39, which is spaced from inner cover 12 a distance L that is greater than the outside diameter D of inlet and discharge pipes 31 and 32, respectively. Extending inwardly from inner. cover lower end 33. and upwardly from around the bottom of inner cover gas inlet opening 34 is duct 40 which extends along the inner surface of the inner cover to a location above base 11. Duct 40 has an open upper end 41 and comprises sidewalls 42 and inner wall 43.
  • gaseous atmosphere from a source passes through inlet pipe 31, inlet enclosure 36, inner cover gas inlet opening 34 and duct 40 into heating chamber 13.
  • the gaseous atmosphere is circulated within heating chamber 13 by means of fan impeller 26 and passes from the heating chamber through inner cover discharge opening 35, discharge enclosure 36', and discharge pipe 32.
  • Base sheath 17, for reasons hereinafter disclosed, is designed to be gastight.
  • base sheath 17, which encloses refractory pedestal 16 comprises annular bottom plate 44, outer sideplate 45, which extends upwardly from adjacent the outer periphery of .the 7 bottom plate, inner sideplate 46, which extends upwardly from adjacent the inner periphery of the bottom plate, and top plate 47- having downwardly extending outer and inner peripheral flanges 48 and 49, respectively.
  • Outer and inner sideplates 45 and 46 are secured to bottom plate 44 by welding the members together to form gastight joints.
  • annular sheath troughs 50 and 51 are partially embedded in refractory pedestal 16, adjacent its upper outer and inner peripheries, respectively.
  • Troughs 50. and 51 contain a mass of sealing material 52, such as lead, which is liquid at furnace operating temperatures.
  • Top plate outer flange 48 extends downwardly into sealing material 52 in sheath outer trough 50, and top.
  • plate inner flange 49 extends downwardly into sealing material 52 in sheath inner trough 51, thereby providing a gastight joint between top plate 47 and troughs 50 and 51.
  • sheath outer sideplate 45 is joined to. sheath outer trough 50 by means of weld 53 which serves to make this joint gastight.
  • weld 53 serves to make this joint gastight.
  • shea modified form of construction is shown in detail in FIG. 5.
  • Sheath inner sideplate 46 is provided, adjacent its upper end,
  • sheath gas inlet pipe 55 and discharge pipe 56 extend, on opposite sides of the sheath, through bottom plate 44 into sheath chamber 60 and through. refractory pedestal 16 to channel 57 which extends in a circle in the top of pedestal 16, adjacent the underside of top plate 47.
  • a nonreactive sealing gas, such as hydrogen, is introduced into channel 57 of sheath chamber. 60 through sheath gas inlet pipe 55 at a pressure higher than that of the reactive gaseous atmosphere circulated through heating chamber 13.
  • This sealing gas flows through channel 57 in the top of pedestal 16, pressurizes sheath chamber 60, and is discharged from it through pipe 56
  • nonreactive sealing gas will escape from, the sheath chamber. Because of'the higher pressure of the sealing gas there will be no infiltration of the reactive gaseous atmosphere from the heating chamber into the sheath or through it to the area beneath the base.
  • An existing base can easily be modified to place the gas inlet and outlet connections in the base peripheral trough, and a removable inner cover can be altered to include gas inlet and discharge openings 34 and 35 and their respective enclosures.
  • a new inner cover may be constructed with a diameter sufficiently large that its lower end will extend into the base peripheral trough in the space between trough outer sidewall 28 and inlet and discharge gas pipes 31 and 32.
  • a furnace having a base and a removable cover thereon forming therewith a heating chamber through which a gaseous atmosphere is circulated, the combination comprising:
  • A. a base sheath comprising;
  • a top, plate having:
  • said trough having; 1 a bottom, 2. outer and inner sidewalls,
  • E. means extending out of said trough, through the bottom thereof, for discharging said gaseous atmosphere from said heating chamber.
  • said removable cover sidewall means has first and second openings adjacent the lower end thereof and first enclosure means surrounding at least the top and side portions of said first opening and second enclosure means surrounding at least the top and side portions of said second opening, each said first and said second enclosure means extending outwardly from said removable cover sidewall means and downwardly into said trough below the surface of said sealing means therein.
  • said removable cover sidewall means has a third enclosure means on the inner surface thereof surrounding the bottom and side portions of said first opening, said third enclosure means having an open top end.
  • A. a base sheath comprising;
  • said base sheath includes a bottom plate which extends between said outer and inner peripheral sideplates and a refractory pedestal is enclosed by said sheath.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Furnace Details (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
  • Control Of Heat Treatment Processes (AREA)
US790578A 1969-01-13 1969-01-13 E furnace Expired - Lifetime US3554511A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US79057869A 1969-01-13 1969-01-13

Publications (1)

Publication Number Publication Date
US3554511A true US3554511A (en) 1971-01-12

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ID=25151129

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US790578A Expired - Lifetime US3554511A (en) 1969-01-13 1969-01-13 E furnace

Country Status (8)

Country Link
US (1) US3554511A (enExample)
JP (1) JPS5017425B1 (enExample)
BE (1) BE744269A (enExample)
CA (1) CA936685A (enExample)
DE (1) DE2001006A1 (enExample)
FR (1) FR2033234A1 (enExample)
GB (2) GB1259725A (enExample)
NL (1) NL7000379A (enExample)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3860224A (en) * 1973-10-19 1975-01-14 Eveleth Taconite Company Apparatus for use in pelletizing ore
US4867675A (en) * 1988-06-15 1989-09-19 Blackman Calvin C Method and apparatus for quickly purging atmosphere gas from bell furnace
US5006064A (en) * 1989-12-28 1991-04-09 Alloy Engineering Company Furnace seal

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3693955A (en) * 1971-03-15 1972-09-26 Bethlehem Steel Corp Component annealing base
GB2262153A (en) * 1991-11-12 1993-06-09 Apv Corp Ltd Insulated panels for heated or cooled enclosures
DE4327975A1 (de) * 1993-08-19 1995-02-23 Loi Ind Ofenanlagen Verfahren und Vorrichtung zum Austauschen der Atmosphäre in einem Haubenglühofen
AT402508B (de) * 1995-02-24 1997-06-25 Ebner Peter H Glühsockel für haubenglühöfen

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2998236A (en) * 1956-07-16 1961-08-29 Cramer Hans Method of annealing in bell furnaces

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2998236A (en) * 1956-07-16 1961-08-29 Cramer Hans Method of annealing in bell furnaces

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3860224A (en) * 1973-10-19 1975-01-14 Eveleth Taconite Company Apparatus for use in pelletizing ore
US4867675A (en) * 1988-06-15 1989-09-19 Blackman Calvin C Method and apparatus for quickly purging atmosphere gas from bell furnace
US5006064A (en) * 1989-12-28 1991-04-09 Alloy Engineering Company Furnace seal

Also Published As

Publication number Publication date
GB1259725A (en) 1972-01-12
BE744269A (fr) 1970-07-09
FR2033234A1 (enExample) 1970-12-04
NL7000379A (enExample) 1970-07-15
JPS5017425B1 (enExample) 1975-06-20
GB1259726A (en) 1972-01-12
DE2001006A1 (de) 1970-07-23
CA936685A (en) 1973-11-13

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