US3328015A - Heat treatment furnaces - Google Patents

Heat treatment furnaces Download PDF

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Publication number
US3328015A
US3328015A US361446A US36144664A US3328015A US 3328015 A US3328015 A US 3328015A US 361446 A US361446 A US 361446A US 36144664 A US36144664 A US 36144664A US 3328015 A US3328015 A US 3328015A
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Prior art keywords
furnace
station
coils
hub
heat treatment
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Expired - Lifetime
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US361446A
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English (en)
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Becker Walter
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Individual
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Individual
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    • 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
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • 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
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment

Definitions

  • This invention relates to continuous furnaces for the heat treatment of rolled stock which has been wound into coils, for example for the bright annealing of coils of steel strip.
  • rolled stock in wire and strip form must have a com letely uniform material structure over its whole length, and it is difficult to achieve this with the conventional devices in the heat treatment given to normalize or structurally convert coils of rolled stock.
  • the difficulties increase in proportion to the size of the coils. It is technically impossible to heat treat coils of more than 2 metres diameter in the pot of a pot type annealing furnace, and it is economically unsatisfactory to anneal such large coils below the hood.
  • such a furnace comprises a number of heat treatment stations and a conveyor for conveying the coils step by step from one station to the next, the conveyor comprising a conveyor beam, at least one carriage which is movable along the beam and a hub which is arranged to pass through and support a coil and is rotatably suspended from the carriage at each end, and each station having at least one driving shaft which extends from the furnace wall and is axially movable to enable it to be introduced into the hub to rotate the hub and thus to rotate the coil at the station.
  • the coils can be rotated in the treatment chamber during the treatment stage which is critical for the final structure so that despite a stationary or sluggishly moving furnace atmosphere and despite temperatures being different at different levels in the treatment chamber, the coils are heated and recooled very uniformly without being borne for any prolonged length of time at the same places where the heat supply may be impaired.
  • the hub is suspended from the carriage at each end by a loop or belt and the beam is movable upwards and downwards, downward movement after the shaft has been introduced into the hub transferring the load of the hub and coil to the shaft and releasing the 'ice hub from the loops or belts to enable the hub to be rotated.
  • the hubs For reliable guiding of the coils on the hubs and to locate the hubs within the loops, the hubs have flanges between which the coils are received and the loops which engage around the hubs outside the flanges are interconnected at their bottoms, e.g., by turnbuckles.
  • the loops may be moved along the conveyor beam which is preferably an I beam by carriages which run along the bottom flange. To move the carriages they may have sets of teeth which engage in the bottom runs of endless driven chains; the bottom runs extending on each side of the web between the carriage and the top flange of the beam.
  • the stations are adapted to be closed off from one another and from the outside by externally operated doors.
  • special door chambers forming locks are disposed between consecutive treatment stations and before and after the end stations, the chambers being adapted to be closed off from each adjacent station and from the outside by externally operated doors. Consequently, each treatment station has a reliable closure in each direction in the form of two doors with an air space therebetween.
  • an entry lock and an exit lock are provided.
  • the heat treatment stations comprise electric or gas heating elements which supply heat directly to the side surfaces of the coils.
  • a preheating station may precede the heat treatment station, to shorten the warming-up time, and the heat treatment station is followed by a heat-exchange station providing a controlled cooling of the heat-treated material from the heat-treatment temperature.
  • the heat exchange station comprises, laterally adjacent the coils, heat-exchange ducts through which the protective gas preheated in the preheating station is conveyed and is returned to the preheating station.
  • FIGURE 1 is a side view of the suspended coil
  • FIGURE 2 is a vertical cross-section of the coil shown in FIGURE 1;
  • FIGURE 3 is a section similar to FIGURE 2, but showing the parts differently disposed;
  • FIGURE 4 is a side view similar to FIGURE 1, but showing the parts differently disposed;
  • FIGURE 5 is a side view of parts of the furnace adjacent those shown in FIGURE 1;
  • FIGURE 6 is a view similar to FIGURE 5 but showing the part differently disposed
  • FIGURE 7 is a section similar to FIGURE 2, but showing a different part of the furnace
  • FIGURE 8 is a section similar to FIGURE 5, but showing yet another part of the furnace
  • FIGURE 9 is a side view to a smaller scale of another part of the furnace.
  • FIGURE 10 is a side view similar to FIGURE 9, but showing another part of the furnace;
  • FIGURE 11 is a vertical section of the part of the furnace shown in FIGURE 10;
  • FIGURE 12 is a section through yet another part of the furnace
  • FIGURE 13 is a side view showing another detail of the furnace.
  • FIGURE 14 is a side view showing another detail.
  • a coil A of steel strip is supported by its inner periphery on a bush B between flanges D.
  • the bush B is suspended in two wire loops C which engage around the bush outside the flanges D and are interconnected at their bottoms by a turnbuckle E.
  • the loops C are suspended through a carrier framework F from a carriage G.
  • the carriage G has four rollers J running on the bottom flange of an I-beam K.
  • the carriage G engages through a top set of teeth L with the bottom run M of a stepwise driven roller chain running below the top flange of the beam K.
  • the chain moves a number of carriages of the kind shown in the drawings through the furnace treatment chamber simultaneously.
  • the furnace chamber is subdivided into a number of consecutive treatment stations and comprises, in this example which is for bright annealing strip steel, a preheating station, an annealing station, a heat exchange station for the controlled cooling of the coils from the annealing temperature, and at least one cooling station to cool the coils substantially to ambient temperature.
  • coaxial driving shafts N are provided which extend through the furnace walls and which each have a journal P at their end extending into the furnace chamber.
  • the journals P are aligned with the axis of the bush B which has entered the treatment station.
  • the shafts N are moved axially to introduce their journals P into the bushes B.
  • the beam K is then lowered by a vertical distance H into the position shown in FIGURE 3.
  • the bush B bearing the coil A then engages with the journals P and the loops C are disengaged from the bush B so that the bush B can be rotated by the shafts N.
  • the bush B as it rotates, rotates the coil A on it, so that the coil rotates in the same sense as the bush B but at a lower speed than the bush.
  • FIGURES 5 and 6 show the way of suspending the vertically movable beam K on the furnace frame.
  • the beam K is suspended through the agency of links k on one horizontal arm each of bell-crank levers Q mounted on the furnace frame for pivoting around horizontal axes, the downwardly extending arms of the levers Q being connected via links q to a thrust rod.
  • the beam K is shown in its top position in FIGURE 5 and in its bottom position in FIGURE 6.
  • FIGURE 7 which is a vertical cross-section through the annealing station, shows as well as the means for suspending and moving the coils A, bearings O for the shafts N.
  • the bearings are themselves gastight and are a gastight fit in the furnace side walls.
  • the casings of the bearings 0 also receive drives for moving the externally rotated shafts N in an axial direction.
  • FIGURE 7 also shows heating elements R disposed laterally adjacent the coil A between the coil and the furnace walls.
  • the elements R are gas-heated radiant tubes with bottom gas feeds and top gas flues.
  • FIGURE 8 shows a heat exchange station which follows the annealing station and which provides controlled cooling of the coil from the annealing temperature.
  • heat exchange tubes S are disposed laterally adjacent the coil A, which in this illustration is borne by the journals P and are disposed between the coil A and the furnace walls.
  • a cool protective gas is supplied to 4 the tubes S through top ducts U by a blower T which supplies the protective gas heated in the heat exchange station through bottom ducts W and, avoiding the annealing station, to a preheating station preceding the annealing station.
  • FIGURE 9 shows the preheating station which is the first treatment station of the furnace and is therefore preceded by an entry lock which is shown to the left of the preheating station in FIGURE 9 and which has an outer door a
  • the preheating station chamber which has provision for rotating the coils introduced into it, is directly supplied with hot inert gas through top delivery apertures in the ducts W extending from the heat exchange station.
  • the protective gas after yielding much of its heat to the coil A, passes from the preheater chamher through slots into the top ducts U and thence, via the heat exchange tubes S, back to the heat exchange station.
  • FIGURE 10 shows a cooling station at the end of the furnace followed, as shown on the right in the drawing, by an exit lock having an outer door a If required, a number of cooling stations can be provided depending upon the amount of cooling required.
  • the cooling station has no provision for rotating the coils since the coils do not pass through critical temperature ranges in the cooling station.
  • the cooling station has cooling tubes disposed on its side walls and extending to cooling boxes in the top part of the cooling station. Also shown in FIGURES 9 and 10 are the door chambers disposed between consecutive furnace stations and between each end station and its lock.
  • Each door chamber is shown to an enlarged scale and in horizontal section in FIGURE 12. Each door chamber can be closed off from the adjacent station or lock by an externally operated double door X.
  • FIGURES 13 and 14 show details of the conveyor chain at the start and end of the furnace.
  • a reversing roller U disposed in the entry lock has a smooth surface on its periphery.
  • a toothed tensioning roller Y which is mounted .at the free end of a single-armed lever and which compensates for variations in chain length especially those caused by the lowering and raising of the beam K.
  • the tensioning roller Y together wit-h the smooth reversing roller U, facilitates the introduction of the carriages G until their teeth L engage with the bottom chain run M.
  • the bottom chain run M first passes upwards over a smooth guide roller and only then runs over a toothed reversing roller U at a higher level.
  • the bottom run M is disengaged from the teeth L between the last-mentioned two rollers.
  • the roller U also serves to drive the chain (see FIG- URE 10).
  • the vertically movable beam K need extend only through those of the stations which have provision for rotating the coils.
  • the beams K K in the locks can be fixed in position as can the carrier beams in the cooling stations. This is why a separation is shown in FIGURE 9 between the vertically movable beam K and the stationary beam K which extends from the preheating station through the entry lock.
  • the protective gas for the furnace atmosphere is supplied at some suitable place, such as the centre of the furnace, then flows in both directions to the locks.
  • the locks have non-return valves V V through which, after the outer doors a :1 have been closed and after the intermediate doors have been opened, the protective gas entering the lock displaces the atmospheric air which has entered the locks during the charging and emptying of the furnace.
  • the furnace including the locks should always be operated with the inert gas at a measurable pressure above atmospheric pressure. It is therefore very important for the outer and inner lock doors to close tightly.
  • a continuous furnace for heat treating coils of steel strip and the like comprising a number of heat treatment stations and a conveyor for conveying the coils step by step from one station to the next, the conveyor comprising a conveyor beam, at least one carriage which is movable along the beam and a hub which is arranged to pass through and support a coil and is suspended from the carriage at each end, and each station having at least one driving shaft which extends from the furnace wall and is axially movable to enable it to be introduced into the hub and to rotate the hub upon the disconnection thereof from the carriage and thus to rotate the coil at the station. 7
  • a furnace according to claim 1 in which the hub is suspended from the carriage at each end by a loop or belt and the beam is movable upwards and downwards, downward movement after the shaft has been introduced into the hub transferring the load of the hub and coil to the shaft and releasing the hub from the loops or belts to enable the hub to be rotated.
  • a furnace according to claim 2 in which the hub has two flanges between which the coil is arranged to fit and the loops or belts support the hub outside the flanges and have their bottoms connected together.
  • a furnace according to claim 4 in which the bottoms of the loops or belts are connected together by a turn-buckle.
  • a furnace according to claim 2 in which the conveyor beam is an I-beam and the carriage runs on the bottom flange of the beam and has two sets of teeth which engage in the bottom runs of endless driving chains which extend one along each side of the web of the beam between the top of the carriage and the top flange of the beam.
  • a furnace according to claim 9 in which a preheating station precedes the heat treatment station and a heat exchange station follows the heat treatment station and a blower is provided for circulating protective gas through ducts between heat exchange tubes at the heat exchange station and the chamber of the preheating station.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
  • Tunnel Furnaces (AREA)
US361446A 1963-04-29 1964-04-21 Heat treatment furnaces Expired - Lifetime US3328015A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEB71702A DE1179966B (de) 1963-04-29 1963-04-29 Durchlaufofen zur thermischen Behandlung von Walzgutbunden

Publications (1)

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US3328015A true US3328015A (en) 1967-06-27

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US361446A Expired - Lifetime US3328015A (en) 1963-04-29 1964-04-21 Heat treatment furnaces

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US (1) US3328015A (de)
AT (1) AT254241B (de)
BE (1) BE646878A (de)
CS (1) CS155130B2 (de)
DE (1) DE1179966B (de)
GB (1) GB989713A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108555160A (zh) * 2018-04-13 2018-09-21 武汉理工大学 应用于热冲压的适用于钢铝混线生产的热冲压挂式加热炉

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2254525A (en) * 1939-09-18 1941-09-02 L A Young Spring & Wire Corp Machine for manufacturing coil springs
US2479102A (en) * 1946-02-23 1949-08-16 Carnegie Illinois Steel Corp Coil annealing furnace
US2507274A (en) * 1947-01-23 1950-05-09 Cold Metal Products Company Furnace
US2580283A (en) * 1947-12-23 1951-12-25 Surface Combustion Corp Coil annealing apparatus
US3220891A (en) * 1962-01-08 1965-11-30 Aluminum Co Of America Annealing sheet metal coils and product

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE757362C (de) * 1939-08-10 1952-07-21 Agnes Jane Reeves Greer Verfahren und Vorrichtung zur Nassbehandlung von Metallspulen

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2254525A (en) * 1939-09-18 1941-09-02 L A Young Spring & Wire Corp Machine for manufacturing coil springs
US2479102A (en) * 1946-02-23 1949-08-16 Carnegie Illinois Steel Corp Coil annealing furnace
US2507274A (en) * 1947-01-23 1950-05-09 Cold Metal Products Company Furnace
US2580283A (en) * 1947-12-23 1951-12-25 Surface Combustion Corp Coil annealing apparatus
US3220891A (en) * 1962-01-08 1965-11-30 Aluminum Co Of America Annealing sheet metal coils and product

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108555160A (zh) * 2018-04-13 2018-09-21 武汉理工大学 应用于热冲压的适用于钢铝混线生产的热冲压挂式加热炉

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Publication number Publication date
BE646878A (de) 1964-08-17
AT254241B (de) 1967-05-10
DE1179966B (de) 1964-10-22
CS155130B2 (de) 1974-05-30
GB989713A (en) 1965-04-22

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