US3695594A - Method and apparatus for operating a pusher type furnace - Google Patents

Method and apparatus for operating a pusher type furnace Download PDF

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Publication number
US3695594A
US3695594A US46650A US3695594DA US3695594A US 3695594 A US3695594 A US 3695594A US 46650 A US46650 A US 46650A US 3695594D A US3695594D A US 3695594DA US 3695594 A US3695594 A US 3695594A
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United States
Prior art keywords
furnace
slabs
rolling
temperature
calculated
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Expired - Lifetime
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US46650A
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English (en)
Inventor
Frans Hollander
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koninklijke Nederlandsche Hoogovens en Staalfabrieken NV
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Koninklijke Hoogovens En Staal
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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
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B9/40—Arrangements of controlling or monitoring devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/004—Heating the product
    • 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
    • F27B9/20—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 the charge moving in a substantially straight path tunnel furnace
    • F27B9/22—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 the charge moving in a substantially straight path tunnel furnace on rails, e.g. under the action of scrapers or pushers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D19/00—Arrangements of controlling devices
    • F27D2019/0028—Regulation
    • F27D2019/0034—Regulation through control of a heating quantity such as fuel, oxidant or intensity of current
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D19/00—Arrangements of controlling devices
    • F27D2019/0028—Regulation
    • F27D2019/0059—Regulation involving the control of the conveyor movement, e.g. speed or sequences
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27M—INDEXING SCHEME RELATING TO ASPECTS OF THE CHARGES OR FURNACES, KILNS, OVENS OR RETORTS
    • F27M2001/00—Composition, conformation or state of the charge
    • F27M2001/15—Composition, conformation or state of the charge characterised by the form of the articles
    • F27M2001/1539—Metallic articles
    • F27M2001/1547—Elongated articles, e.g. beams, rails
    • F27M2001/1552—Billets, slabs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27M—INDEXING SCHEME RELATING TO ASPECTS OF THE CHARGES OR FURNACES, KILNS, OVENS OR RETORTS
    • F27M2003/00—Type of treatment of the charge
    • F27M2003/02—Preheating, e.g. in a laminating line

Definitions

  • This advance control of the furnace is, [56] References Cited during heating and rolling, adjusted by real pushing UNITED STATES TENTS speed and real temperature of the slabs in the furnace. 3 6 Disturbances or delays in rolling entrain first a lower Peck et al. l pp y, and after the delay is over the g g Qi j' 2 2 pushing and rolling are speeded up until the arrears a1 ey, r.
  • FURNACEUS ROLLING MILL TEMPERATURE SLAB SHEET ROLLING TIME FURNACEUS) DATA DATA PER SLAB DESIRED T CONTVROL PROGRAM DESIRED PUSHING FURNACEUS) FURNACEUS) PROGRAM FUEL 4 REAL PUSHING qu mn'u PROGRAM ADJUSTMENT MOMENT SLAB FUEL LEAVES FURNACE INVENTOR F04: 27am A A ATTORNEY PATENIEDum m2 3.695, 594
  • the rolling is started from steel slabs.
  • Such slabs are pushed in contact with one another through a pusher type furnace and during their presence in said furnace they are heated to a temperature of about l,200 C. After heating, the slabs are one after the other taken from the furnace and rolled out, as a rule each in two mutually separated series of rolling passages one after the other.
  • Such series of passages aresometimes called the cogging or roughing mill passages and the finishing passages respectively.
  • Pusher type furnaces are generally known, e.g., from U.S. Pat. No. 3,022,056 to William H. Dailey, Jr, and from Iron and Steel Engineer, April, 1959, pp. 102-110.
  • the temperature control of the material before the finishing train requires a control of temperature of the slabs before the roughing mill within about accuracy.
  • the temperature of the slab when leaving the pusher type furnace is a value, which is difficult to control and which among others depends on the dimensions of the slabs, the time of presence of the slabs inthe furnace in different zones thereof and the rolling program. ln practice the pusher type furnace is controlled in such a way that the slabs leave this furnace with a temperature which is about optimum for rolling out.
  • the invention consists in that the quantity of fuel supplied to different zones of the furnace(s) and the rate of speed of passage of the slabs or the like through the furnace(s) are controlled (adjusted) in advance on the basis of data-relating to the slabs or the like supplied to the furnace(s) and also to the desired information about the dimensions of the sheet to be rolled, the finishing temperature at the end of the hot rolling and the rolling practice (program and time) to be followed, which data in the course of the rolling process are used and treated in combination.
  • control data for the desired speed of passage of the slab or the like through the furnace are calculated on the basis of an optimum rolling and ceiling program in and following the finishing. train, that on the basis of this rolling program are calculated first the temperature of the product when entering the finishing train, from this value the temperature thereof when leaving the cogging train, and from this value, in combination with the data about the slab, the required average slab temperature when it leaves the furnace, after which from the last-mentioned temperature and from the calculated speed of passage through the furnace the furnace conditions are derived.
  • the furnace program which is primarily controlled in advance, is secondarily adjusted or additionally controlled for correction.
  • the course of the surface temperature of the slabs in the furnace(s) may be determined in part by direct measurement and in part by calculations. Such calculations, which are performed by electric means in such a case mainly relate to eliminating of measuring inaccuracies as a result of the reflection of the walls and the radiation of combustion gases.
  • the amount in which the furnaces are temporarily brought to a lower level and wherein thereafter the pushing through program and the furnace heat generation are brought to a higher level may be determined both along empirical and along mathematical ways.
  • the circuit includes a computer for determining the furnace control program during the process connected and adjusted so as to be fed with data about dimensions and composition of the slabs or the like to be supplied to the furnace, and with the data of the desired dimensions, finishing temperature and rolling time of the product to be made therefrom, so that this computer makes a control program for adjusting in advance the quantity of fuel to be supplied per zone of the furnace and a program for the moments of removing the heated slabs from the furnace, through the determinations of the desired temperature conditions in the furnace and the desired program of pushing the slabs through the furnace, and that this computer moreover is taken up in a control circuit which also includes means for adjusting the passage program for the slabs or the like through the furnace, determined by the said control program for advance adjusting, and includes means for controlling the required definite pushing through program, also in dependence upon the real rolling practice determined during the process.
  • the method is perfected by having the additional control (adjustment) alsotake place on the basis of determinations of the course of the surface temperature of the slabs in the furnace(s), and on the basis of calculations of the course of the temperature through said slabs, it is recommendable to embody this circuit moreover in such a way that said computer is also taken up in a second control circuit, which comprises means for adjusting a desired temperature distribution in the furnace(s) and means for controlling the quantity of fuel required thereto, also in dependency upon the temperature conditions in the furnace(s) determined during the process.
  • FIG. 1 gives in general the course of the temperature of the material to be rolled through the rolling mill.
  • FIG. 2 shows diagrammatically the course of the heating up.
  • FIG. 3 is a somewhat diagrammatic drawing of a pusher furnace.
  • FIG. 4 gives diagrammatically only the main parts of the circuit for control (adjustment) in advance of the furnace(s).
  • FIG. 5 is a diagram of circuit for a complete control program of the furnace( s).
  • the temperature T of the material to be rolled is plotted against the time of stay tof the product in a rolling mill.
  • a vertical dot and dash line gives the transition from the upstream cogging train to the downstream finishing train, at which point the temperature is T,.
  • the temperature T is, as remarked before, critical for the course of therolling process in the finishing train. If T, is too low, the quality of the material will be inferior, the rolling forces will be too high or even the sheet will be to cold and will have to be taken from the table at a point before the finishing train. If T, is too high, the sheet should first be allowed to cool down or should be rolled out too slowly. In both cases production loss and disturbance of control of the furnace are the result. Determinative for Tis the slab temperature T p when leaving the pusher furnace.
  • a dotted line shows the point in the furnace where the first or upstream upper and lower flame zones terand a heating through of the slabs take place. Considerable corrections in the slab temperature can no morebe made.
  • FIG. 3 a pusher furnace has been given diagrammatically, having five flame zones.
  • Reference numerals 1 to 5 incl. each indicatea row of burners, said row extending transversely to the plane of the drawing.
  • the slabs 6 are pushed through in the direction of the arrows, therewith sliding over cooled rails 7.
  • FIG. 4 in principle indicates how the control program of the furnace(s) is built up.
  • the diagram is divided by dotted lines, into three horizontal zones, comprising from top to bottom the input data of the furnace control, the computer operations and the actions which result therefrom on the process respectively.
  • the data of the slabs to be treated, the desired data of the rolled sheet and the desired data of the desired final rolling practice can be put in with the aid of punched cards, punched tapes or magnetic tapes in a manner known as such.
  • this control program includes an optimum programming of the course of the process during and after the finishing rolling. From this programming the control programdetermines step by step theconditions necessary therefore, each time in an earlier phase of the process, from finishing rolling. to conditions at the furnace. Finally the required furnace conditions result therefrom, which allow the surface temperature and the average temperature of the slabs, at and dependent on the moment at which the slabs leave the furnace to take a course, so as to attain the desired values.
  • the control program on the basis thereof calculates the starting values for the actions to be taken.
  • FIG. 5 again has been divided by horizontal dotted lines into three horizontal zones, from top to bottom for input data, for operations and for actions respectively.
  • FIG. 5 it has been indicated that as additional input data the measured furnace temperature and the really observed pushing program are introduced. If and insofar as these deviate from the desired conditions it is possible to have the control program make corrections to the actions to be exerted. By introducing feed backs in the program as given in this Figure, this results in a combination of an on-line process, controlled in advance, and an in-line additional control thereof.
  • the control program the measured course of the furnace temperature is operated upon by calculation to give a surface temperature and an average temperature for each slab. With the aid thereof the fuel supply and the pushing program can at any moment be adapted to small deviations.
  • a pusher type furnace having an upstream end into which the metal slabs are fed and having a downstream end to which they are pushed during the reheating, said furnace having fuel fed heating devices therein,
  • a rolling mill having an upstream end to which reheated slabs are delivered from the downstream end of said furnace
  • step (b) adjusting the rate of pushing of said slabs in the 5 furnace and the flow of fuel to said heating devices nace to reduce deviations between the data supplied in step (d) and the corresponding item of data calculated in step (b).
  • step (d) which the actual temperature data supplied in step (d) is based on the course of the surface temperatures of the slabs in the furnace, in which the computer is programmed to calculate the average temperatures of the slabs on the basis of said surface temperatures and the course of the temperature equalization through the work, and in which the secondary adjustments of step (e) are effected to reduce deviations between said average temperatures and the temperatures calculated in step (b) (6).
  • An improved method as claimed in claim 1 particularly applicable when fuel fed heating devices in the furnace are arranged in an upstream set above and below the path of pushing of the slabs in the furnace, and in a downstream set above the path of pushing of the slabs in the furnace, and in a third set intermediate 7.
  • step (b) data item (5) is calculated on the basis of a desired optimum rolling and coiling program in and following such finishing mill, by calculating therefrom the speed of passage of the slabs through the furnace and the value of temperature of the work desired at the upflow of fuel and of pushing of the slab in the furstream end of the finishing mill, calculating from said value of temperature the temperature level for the work leaving the cogging mill, and calculating from said temperature level in combination with data item (1) supplied to the computer in step (a), the required average temperatures for the slabs when they leave the downstream end of the furnace; and in which the data of item (8) of step (b) are calculated from said average temperature and the calculated rate of pushing of the slab through the furnace.
  • an apparatus for reheating work in the form of metal slabs for rolling sheet or strip therefrom said apparatus being of the type which comprises i. a pusher type furnace having an upstream end into which the metal slabs are fed and having a downstream end to which they are pushed during the reheating, said furnace having fuel fed heating devices therein,
  • a rolling mill having an upstream end to which reheated slabs are delivered from the downstream end of said furnace
  • a computer the improvement which comprises a. means for supplying advance data as to l the dimensions of the slabs to be heated,
  • adjusting and control means having advance data inputs connected to receive the advance data from said means (a) and having outputs connected to control the flow of fuel to said heating devices and the rate of pushing of the slabs in the furnace, said adjusting and control means being programmed to calculate from said advance data 5. the calculated temperature of the work required at the beginning of the finish rolling thereof,
  • said adjusting and control means has further input means connected to receive from said rolling mill during its operation data as to the actual rolling practice being realized therein, and wherein said adjusting and control means further comprises means responsive to the data received by said further input means for secondarily adjusting at least one of the rates of flow of fuel and of pushing of the slabs in the furnace to reduce deviations between the data recorded by said further input means and the corresponding advance data received by said advance data inputs,
  • said adjusting and control means (b) has further input means connected to receive from said furnace during the reheating operation data as to the temperatures actually existing in the furnace and the pushing rates actually being effected therein, and wherein said adjusting and control means further comprises means responsive to the data received by said further input means for secondarily adjusting at least one of the rates of flow of fuel and of pushing of the slabs in the furnace to reduce deviations between the data received by said further input means and the corresponding advance data received by said advance data inputs.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Heat Treatment Processes (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)
US46650A 1969-08-13 1970-06-16 Method and apparatus for operating a pusher type furnace Expired - Lifetime US3695594A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL6912326.A NL167238C (nl) 1969-08-13 1969-08-13 Inrichting voor de regeling van ovens voor staalplak- ken.
NL7000722A NL7000722A (de) 1969-08-13 1970-01-19

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US3695594A true US3695594A (en) 1972-10-03

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US46650A Expired - Lifetime US3695594A (en) 1969-08-13 1970-06-16 Method and apparatus for operating a pusher type furnace

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US (1) US3695594A (de)
BE (1) BE754752A (de)
CA (1) CA947968A (de)
DE (1) DE2040148B2 (de)
ES (1) ES382683A1 (de)
FR (1) FR2057985A5 (de)
GB (1) GB1317963A (de)
LU (1) LU61511A1 (de)
NL (2) NL167238C (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4087238A (en) * 1976-09-13 1978-05-02 United States Steel Corporation Method for enhancing the heating efficiency of continuous slab reheating furnaces
US4257767A (en) * 1979-04-30 1981-03-24 General Electric Company Furnace temperature control
US4330263A (en) * 1981-03-02 1982-05-18 General Electric Company Method of controlling a reheat furnace to control skid mark effects
US4338077A (en) * 1979-11-26 1982-07-06 Nippon Kokan Kabushiki Kaisha Method for controlling temperature of multi-zone heating furnace
DE3539323A1 (de) * 1984-11-07 1986-05-15 Mitsubishi Denki K.K., Tokio/Tokyo Verfahren zum einstellen der stahlhalbzeug-ausgabetemperatur eines waermeofens einer warmwalzenstrasse
US4606006A (en) * 1981-10-05 1986-08-12 Mitsubishi Denki K.K. Method of controlling the rolling efficiency in hot rolling
US5857847A (en) * 1997-04-17 1999-01-12 Chrysler Corporation Brazing furnace parts feeding control

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5848011B2 (ja) * 1979-11-26 1983-10-26 日本鋼管株式会社 加熱炉燃焼制御方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2872173A (en) * 1949-12-12 1959-02-03 Munker Theo Method and apparatus for heat treating materials in a continuous operating furance
US3022056A (en) * 1957-11-29 1962-02-20 Midland Ross Corp Combustion controls for metallurgical heating furnaces
US3294382A (en) * 1960-08-18 1966-12-27 Hupp Corp Heat treating apparatus
US3385579A (en) * 1965-12-08 1968-05-28 Westinghouse Electric Corp Slab heating apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2872173A (en) * 1949-12-12 1959-02-03 Munker Theo Method and apparatus for heat treating materials in a continuous operating furance
US3022056A (en) * 1957-11-29 1962-02-20 Midland Ross Corp Combustion controls for metallurgical heating furnaces
US3294382A (en) * 1960-08-18 1966-12-27 Hupp Corp Heat treating apparatus
US3385579A (en) * 1965-12-08 1968-05-28 Westinghouse Electric Corp Slab heating apparatus

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4087238A (en) * 1976-09-13 1978-05-02 United States Steel Corporation Method for enhancing the heating efficiency of continuous slab reheating furnaces
US4257767A (en) * 1979-04-30 1981-03-24 General Electric Company Furnace temperature control
US4338077A (en) * 1979-11-26 1982-07-06 Nippon Kokan Kabushiki Kaisha Method for controlling temperature of multi-zone heating furnace
US4330263A (en) * 1981-03-02 1982-05-18 General Electric Company Method of controlling a reheat furnace to control skid mark effects
US4606006A (en) * 1981-10-05 1986-08-12 Mitsubishi Denki K.K. Method of controlling the rolling efficiency in hot rolling
DE3539323A1 (de) * 1984-11-07 1986-05-15 Mitsubishi Denki K.K., Tokio/Tokyo Verfahren zum einstellen der stahlhalbzeug-ausgabetemperatur eines waermeofens einer warmwalzenstrasse
US4709570A (en) * 1984-11-07 1987-12-01 Mitsubishi Denki Kabushiki Kaisha Method for setting steel stock discharge temperature of heating furnace in hot rolling line
US5857847A (en) * 1997-04-17 1999-01-12 Chrysler Corporation Brazing furnace parts feeding control

Also Published As

Publication number Publication date
GB1317963A (en) 1973-05-23
FR2057985A5 (de) 1971-05-21
BE754752A (nl) 1971-02-12
NL167238C (nl) 1981-11-16
NL6912326A (de) 1971-02-16
DE2040148B2 (de) 1972-09-28
CA947968A (en) 1974-05-28
DE2040148A1 (de) 1971-02-25
ES382683A1 (es) 1973-04-16
LU61511A1 (de) 1970-10-22
NL7000722A (de) 1971-07-21

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