US3267709A - Method and apparatus for controlling temperature of the workpiece during rolling - Google Patents

Method and apparatus for controlling temperature of the workpiece during rolling Download PDF

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Publication number
US3267709A
US3267709A US302024A US30202463A US3267709A US 3267709 A US3267709 A US 3267709A US 302024 A US302024 A US 302024A US 30202463 A US30202463 A US 30202463A US 3267709 A US3267709 A US 3267709A
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strip
temperature
train
speed
finishing
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US302024A
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English (en)
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O'brien Jeremiah Wagner
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United Engineering and Foundry Co
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United Engineering and Foundry Co
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product

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  • This invention relates to a method of and apparatus for rolling metallic elongated workpieces and, more particularly, to a hot strip rolling mill incorporating a continuous tandemly arranged finishing train.
  • the present invention not only overcomes the abovementioned shortcomings of the previous means and methods of temperature control of the strip in the finishing train of a hot strip mill, but of even more significance, it successfully meets the demands of the modern strip mills wherein very long coils are produced.
  • a method of and apparatus for controlling the hot rolling of strip wherein the end-to-end temperature differential of the strip during rolling in the finishing train can be greatly reduced and, if necessary, substantially totally eliminated; and, wherein, if desired, the temperature level of the strip during the rolling operation can be automatically and narrowly controlled.
  • the finishing train is operated so that the speed of each stand thereof is proportionately increased in unison as the strip is rolled, whereby the rearward portions of the strip are introduced into the first mill stand at a greater velocity than the forward portions thereof.
  • the speed ratio of the stands will not necessarily be disturbed.
  • the end-to-end temperature differential of the strip may be substantially decreased and a substantial constant temperature condition obtained throughout the entire strip.
  • the required increase in the delivery velocity of the strip at a given point on the strip necessary to obtain the desired temperature at that point will equal the sum of the temperature losses incident to radiation and conduction of an earlier point on the strip multiplied by the delivery velocity of the earlier point, which product is divided by the sum of the temperature losses incident to radiation and conduction of the earlier point subtracted from the difference in temperature between the given and earlier points as these points enter the train.
  • the speed of the finishing train, runout table and strip coiler will be adjusted in unison, in which regard the speeds of these units will be accelerated immediately after the strip has been started on the mandrel of the coiler.
  • the speeds of the train can be progressively and continuously increased as soon as the material is in the train and the speeds of the other units will be raised to match that of the train as the material passes to them, the initial speed of the train being within the limits that assure successful conveyance of the strip over the runout table and commencement of the coiling operation.
  • FIGURE 1 is a schematic elevational view of a finishing train of a hot strip mill, illustrating also the runout table and the strip downcoilers thereof;
  • FIGURE 2 is a schematic view of one of the mills shown in FIGURE 1, illustrating the roll pass adjustment mechanism thereof;
  • FIGURE 4 is a graph illustrating the result of varying the speeds or" the strip in relationship to the length of the strip being processed.
  • FIGURE 1 of the drawings there is illustrated for processing a strip S, the finishing end of a continuous hot strip rnill, including a 4-high sixstand finishing train consisting of stands l1, l2, l3, l4, and 15, a runout table 17 and two downcoilers l8 and 19.
  • the motors 2i are shown for the stands, each having a tachometer 22, the tachometer of the stand 16 being shown connected to its motor 21 by a train of gears 23 to which there is also connected a pilot generator 25.
  • the rollers of the runout table 17 are driven by motors 26, two of which only are shown. Above the table 17 there are provided a number of strip cooling sprays 27.
  • the downcoilers lo and 19 are driven by motors 23, each having a control 29 which is electrically connected to the pilot generator 25 of the last stand is of the finishing train.
  • FIGURE 1 also diagrammatically illustrates three temperature detecting devices, such as pyrometers 3b, 31 and 32, the pyrometer 35 being arranged at the entry side of the train, the pyrometer 31 on the exit side thereof and the pyrometer 32 on the entry side of downcoiler 18.
  • an X-ray strip thickness gauge 33 is arranged at the exit side of the mill stand 16.
  • FIGURE 2 which shows a diagrammatic arrangement for adjusting the pass of one of the stands 1146, there is provided a pair of working rolls 34- between which the strip S passes, each working roll being supported by backing-up rolls 35.
  • One of a pair of bearing-checks 36 is also shown for the upper backing-up roll which is engaged by the lower end of the mill screw 37.
  • a gear wheel 33 which is rotated by a worm 3-9, the worm being connected by gearing 41 to a piston cylinder assembly 42 and an electrical motor 43.
  • the motor and piston cylinder assembly serve as a low-speed, high torque and low torque, high-speed prime movers, respectively, the two working together to provide a strip guage control arrangement.
  • FIGURE 1 The rolling equipment illustrated in FIGURE 1 is, of course, well known as exemplified by chapter 33 in the making, shaping, heat treating of steel published by the US. Steel Corporation, 7th edition, and the material referred to in the bibliography thereof
  • the mill screwdown arrangement shown in FIGURE 2 is more fully described in US. patent application No. 3,104,567, issued to M. P. Sieger on September 24, 1963 entitled Rolling Mill Screwdown Apparatus. It will be appreciated that other well-known pass adjusting devices can be employed, such as, illustrated in US. Patent No. 2,961,901 that was issued to S. Wheeler on November 29, 1960 entitled Automatic Control for Adjusting Rolling Mills.
  • the connection between the strip thickness X-ray gauge 33 and the piston cylinder asof the scrcwdown can follow the arrangement in FIGURE 7 of the aforesaid Wheeler patsembly illustrated cut.
  • the motors 21, 26 and 23, provide for the finishing train, the runout table and the downcoilers l8 and respectively, are controlled in a well-known manner so that their speeds can be proportionately varied in unison.
  • the strip cooling device employed with the runout table 14 is constructed also in a Wellwn manner so as to vary its output in accordance with the change in speed of the train. In this manner, as the speeds increase, the discharge from the strip cooling system will increase proportionately.
  • the speed of the finishing train can be adjusted manually or at a given time in relationship to passage of the strip through the mill, this adjustment can be preferably effected by automatically adjusting the speeds of the stands pursuant to the continuous changing temperature condition of the strip being fed through the finishing train.
  • this adjustment can be preferably effected by automatically adjusting the speeds of the stands pursuant to the continuous changing temperature condition of the strip being fed through the finishing train.
  • Another manner of adjusting the mill speeds to correct for the temperature differential would be to utilize a computer to which would be continuously fed either theoretical or empirical relationships of the various factors involved as the temperature changes of the strip during the rolling process.
  • a still further manner would be to op a program system based on past performln this ngard FIGURE 3 illustrates the principal components of the computer system in which there is illustrated diagrammatically the pyrometers 3%, Bl and 32.
  • the amplifier 5-5 has within itself a bias which is in effect an acceleration rate r ,astrnent.
  • the voltage output of the amplifier is therefore modified for a certain accelerating rate.
  • This output in turn, modified the output of amplifier 4'7 to give a certain accelerating rate to the finishing train which will limit the accelerating rate established by the speed of operation of a motoroperated rheostat, not shown.
  • the voltage output of the summing amplifier 4-5 feeds another summing amplifier 51.
  • This amplifier receives three other voltage s nals, a voltage signal rep resenting the temperature or the strip at the entry end of the mill as obtained by the pyrorneter 31' a voltage representing the temperature of the strip at the delivery end of the mill as obtained by the pyrometer 31 and a manual preset voltage signal.
  • the voltage output signal from the amplifier will represent the difference between the signal from the output amplifier 45 and the sum of the signals from the pyrometers 3-53 and 31. This signal will then be sent on to an amplifier which, in turn, feeds a voltage signal to the amplifier :7.
  • the voltage output from the coiler pyrometer 32 is fed to a summing amplifier 48.
  • the amplifier 48 receives a second voltage signal from the tachometer 22, it being noted that the tachometer feeds a voltage signal also to the amplifier 47, the latter signal representing delivery speed of the finishing mill train.
  • the output voltage signal represents the difference between the voltage input from the pyrometer 32 and the tachometer voltage input. This signal will have polarity and is fed to the control of the spray valve section and the cooling water spray valves to increase or decrease the amount of cooling water.
  • Equation 8 the various inputs and outputs of the amplifiers will be expressed in terms of Equation 8 appearing in column 8 as follows:
  • the operational amplifier 47 receives a voltage signal ATC +TR from the amplifier 46, a voltage signal (ATC +ATR )-(Tel1t. Tent. from the amplifiers 51 and 53 and a voltage signal VdeL from the tachometer 22 and solves the aforesaid equation to produce a voltage signal representing the desired delivery speed of the mill to correct for a temperature differential existing between a first point from the strip (P and a second point (P).
  • the various elements making up the aforesaid computer system are of well-known construction, in which the various amplifiers are of the type discussed under operational amplifiers in G. A. Korn et al. Electronic Analog Computers, Second edition, 1956, McGraw-Hill Book Company, Inc.
  • FIGURE 3 it will be noted in FIGURE 3 that it feeds a signal to an operational amplifier 58 which feeds to a motor speed control 59; the operational amplifier 58 also receives signals from rectifiers 61 and 62, the rectfiiers producing signals which are also received by an operational amplifier 63 which is electrically tied in with a pilot servo-system 64 which feeds a signal to an amplifier 65 which, in turn, feeds a signal to a regulator 65.
  • the control 59 there is illustrated one of the motors 21 of the train along with the tachometer 22, in which connection it will be noted that the tachometer 22 is connected to the operational amplifier 47.
  • FIGURE 4 With respect to the matter of operating the train to obtain temperature control which is graphically illustrated in FIGURE 4, it will be seen that a signal from the delivery pyrometer 31 through the amplifiers 45, 46, 47 and 58 will initiate the operation of the control 59, which will then regulate the speed of the motors 21 whereby the temperature level of the strip will be brought to a predetermined value as set by the manual adjustment of the operational amplifier 51. Moreover, it will be seen from FIGURE 3 that the signals of the pyrometers 30 and 31 will be integrated in a manner to produce a signal received by the operational amplifier 47, which through the amplifier 58, will dictate to the control 59 to effect a motor speed change commensurate with the differential detected in the temperature of the strip passing under the pyrometers 30 and 31.
  • P represent a point at the leading end of the strip
  • Temt represent the entering temperature of the strip at the first finishing stand of point
  • P TdeL represent the delivery temperature of the strip at the last finishing stand of point
  • Tent. represent the entering temperature of the strip at the first finishing stand of point P TdeL represent the delivery temperature of the strip at the last finishing stand of point
  • P ATH ATH represent the temperature increase of the strip at points P and P in the finishing train due to heat input by the work of reduction;
  • ATC ATC represent the temperature decrease of the strip at points P and P in the finishing train due to conduction losses between the rolls and strip;
  • ATR ATR represent the temperature decrease as points P and P passed through the finishing train due to radiation losses
  • VdeL VcleL represent the velocity of points P and P as they leave the last stand.
  • Equation 5 If the difference on the right-hand side of Equation 5 does not equal the difference on the left-hand side and, consequently does not fulfill the conditions required for equal finishing temperature, then it is possible to alter the values of (ATC -1-ATR by changing the speed of a finishing train, it follows that the difference between the expression on the right-hand side of the Equation 5 can be made to equal the difference between the expression on the left-hand side thereof. For example, by increasing the speed of the finishing train, the time in which a given portion of the strip passes between the rolls of the stand is reduced and, consequently, the conduction losses are reduced since the portion is in contact with the rolls for a shorter length of time. Similarly, an increase in speed will reduce the time of exposure for a given portion of the strip as it passes between the stands of the train and, consequently, the radiation losses are reduced at these areas.
  • Equation (8) The relationship of velocities in Equation (8) is substantially correct, except for small secondary effects. From the above analysis it is evident that the temperature of the strip can be made substantially constant by varying the speed of the finishing train in the relationships indicated.
  • the initial speed thereof as well as the speed of the runout table 17 will be maintained low enough to assure that the leading end of the strip will be successfully conveyed over the table and started on the mandrel of one of the coilers l8 and I
  • This speed may vary from 1300 f.p.m. to slightly more than 2400 f.p.rn., depending upon the characteristics of the strip being rolled.
  • the maximum speed range of the train may be as high as 3800 f.p.m. Of course, in a mill arrangement wherein the coilers were arranged immediately adjacent the last stand, higher initial speeds could be obtained;
  • the desired rolling temperature of the strip is about 1650 F. and that a portion of the front end leaving the mill is determined to be 1700 F. as detected by the delivery pyrometer 31.
  • the detected temperature being different from the preselected temperature, as fed into the operational amplifier 51 by the manual control, will cause a signal to be produced and sent to the operational amplifier 47 which, in turn, will be fed to the operational amplifier 58 and, hence, to the control 59 which will cause a decrease in the speeds of the motors 21 of the train until the temperature reading of the strip leaving the finishing train is approximately 1600 F.
  • the motors 26 of the runout table and the motors 28 of the particular coilers 18 and 19 that are being employed to receive a strip will also be correspondingly decelerated as well as the output of the sprays 27.
  • the mill speed is adjusted to maintain a predetermined strip temperature level.
  • the speed of the train can be increased within the limit of effective conveyance of the strip to the coilers to increase the temperature of the strip leaving the last stand. A more inexact procedure would be to delay changing the speed of the train until the leading end of the strip is in the coiler.
  • the pyrometer system will signal the speed controller 5? to gradually and proportionately increase the speeds of the train, runi out table, coiler and output of the sprays 27 and, thus, to correct for the strip temperature differential when pass ing through the train so that the strip tWlll have an approximate, controlled temperature of about 165 0 F.
  • the speed change need not be efieeted in a gradual manner, but could be accomplished at timed intervals or in one step. If the difference in speedbetween the front portion of the strip and the remainder thereof is great enough, a reversal of the initial temperature condition may be obtained, so that the rearward end of the strip will be hotter than the forward end thereof as it emerges from the last finishing stand. This condition is a result of the fact that at very high speeds the rate at which heat is introduced into the metal increases while the losses decrease, both to a very considerable extent.
  • the means and method herein disclosed provide for obtaining a substantial constant temperature between each portion of the strip as it passes a given point in the finishing train of a hot strip mill and, in addition, if desired, the refinement of the temperature level of a substantial portion of the strip. Moreover, an incident to the employment of this invention is that the productivity of the mill will be substantially increased.
  • P represents a point at the leading edge of the strip
  • P represents some other point along the strip
  • Tent represent the entering temperature of the strip at the first stand of point
  • P Ta eL represent the delivery temperature of the strip at the last finishing stand of point
  • P T emfl represent the entering temperature of the strip at the first finishing stand of point
  • P TdeL represent the delivery temperature of the strip at the last finish-ing stand of point
  • P ATH ATH represent the temperature increase of the strip at points P and P in the finishing train due to heat input by the work of reduction
  • ATC ATC represents the temperature decrease of the strip at points P and P in the finishing train due to conduction losses between the rolls and strip;
  • ATR ATR represent the temperature decrease as points P and P passed through the finishing trains due to radiation losses
  • Va'eL VdeL represent the velocity of points P and P as they leave the last stand.
  • a speed controller responsive to said signal and to said speed of said one stand, connected to said motors to adjust the speeds thereof to reduce the temperature losses of the strip passing through the train, whereby the difference in temperature between said two points will be reduced.
  • P represents a point at the leading edge of the strip
  • P represents some other point along the strip
  • Tent represents the entering temperature of the strip at the first finishing stand of point
  • P TdeL represents the delivery temperature of the strip at the last finishing stand of point
  • TenL represents the entering temperature of the strip at the first finish-ing stand of point
  • TdeL represents the delivery temperature of the strip at the last finishing stand of point
  • P ATH ATH represent the temperature increase of the strip at points P and P in the finishing train due to heat input by the work of reduction;
  • ATC ATC represent the temperature decrease of the strip at points P and P in the finishing train due to conduction losses between the rolls and strip;
  • 1 1 ATR ATR represent the temperature decrease as points P and P pass through the finishing train due to radiation losses; VdeL Vdeln; representthe velecity of points P and P; as they leave the last stand.
  • said means for determining the temperature comprise pyrorneters located at the entry and delivery sides of the train.
  • strike out "Tdel. represents the delivery temperature of l the strip at the last finishing stand of point P lines 68 and 69
  • strike out "TdeL 2 represents the delivery temperature of the strip at the last finishing stand of point P lines 7O, 71, and 72
  • strike out "ATH ATH represents the temperature increase of the strip at points P and P in the finishing train due to heat input by the work of reduction;”
  • line 73, strike out ",ATC same line 73, for "represent” read represents line 74, for "points” read point same line 74, strike out "and P column 11, line 1, strike out QATR Z"
  • same line 1, for "represent” read represents line 2, for "points read point same line 2, strike out “and P same line 2, for "pass” read passes Signed and sealed this 12th day of September 1967.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Control Of Metal Rolling (AREA)
  • Metal Rolling (AREA)
US302024A 1962-08-24 1963-08-14 Method and apparatus for controlling temperature of the workpiece during rolling Expired - Lifetime US3267709A (en)

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GB32574/62A GB977485A (en) 1962-08-24 1962-08-24 Method and apparatus for controlling strip temperature during rolling

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BE (1) BE636442A (de)
DE (1) DE1293114B (de)
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GB (1) GB977485A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3411332A (en) * 1966-11-10 1968-11-19 Westinghouse Electric Corp Temperature control apparatus and method for operating a reduction rolling mill
US3418834A (en) * 1965-10-21 1968-12-31 Westinghouse Electric Corp Temperature control system and method for operating a reduction rolling mill
US3483721A (en) * 1966-12-30 1969-12-16 Automation Ind Inc Material tester
US5027634A (en) * 1990-02-28 1991-07-02 Granco-Clark, Inc. Solutionizing taper quench

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3604234A (en) * 1969-05-16 1971-09-14 Gen Electric Temperature control system for mill runout table
ATE4962T1 (de) * 1979-08-14 1983-10-15 Davy Mckee (Sheffield) Limited Betrieb eines mehrgeruestigen warmwalzwerkes.
DE3319383A1 (de) * 1983-05-26 1984-11-29 Mannesmann AG, 4000 Düsseldorf Verfahren zum verbessern der aussendurchmesser- und wanddickentoleranzen beim masswalzen und streckreduzieren von rohrluppen
DD249202A1 (de) * 1986-05-20 1987-09-02 Thaelmann Schwermaschbau Veb Verfahren zum kuehlen von walzgut in walzbloecken und gerueststaffeln
CN102615114A (zh) * 2012-03-30 2012-08-01 南京钢铁股份有限公司 一种制链用窄带钢的控温轧制方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2863557A (en) * 1952-02-15 1958-12-09 Munker Theodor Apparatus whitch controls temperature and speed of extruded product
US2983170A (en) * 1958-06-04 1961-05-09 United States Steel Corp System for controlling the gage of strip produced by a continuous rolling mill
US3109330A (en) * 1960-08-24 1963-11-05 Jones & Laughlin Steel Corp Continuous mill control means
US3186201A (en) * 1961-06-21 1965-06-01 Steelworks Automation Ltd Production of metal strip

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE920725C (de) * 1942-02-14 1954-11-29 Schloemann Ag Verfahren zur Erreichung eines bestimmten Temperaturgefaelles ueber die Laenge einesBreitbandes vor dem ersten Geruest der kontinuierlichen Fertigstrasse eines Breitbandwalzwerkes
DE846836C (de) * 1948-10-02 1952-08-18 Siemag Vertriebsgesellschaft M Verfahren und Einrichtung zum Walzen, insbesondere von Band- und Profileisen

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2863557A (en) * 1952-02-15 1958-12-09 Munker Theodor Apparatus whitch controls temperature and speed of extruded product
US2983170A (en) * 1958-06-04 1961-05-09 United States Steel Corp System for controlling the gage of strip produced by a continuous rolling mill
US3109330A (en) * 1960-08-24 1963-11-05 Jones & Laughlin Steel Corp Continuous mill control means
US3186201A (en) * 1961-06-21 1965-06-01 Steelworks Automation Ltd Production of metal strip

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3418834A (en) * 1965-10-21 1968-12-31 Westinghouse Electric Corp Temperature control system and method for operating a reduction rolling mill
US3411332A (en) * 1966-11-10 1968-11-19 Westinghouse Electric Corp Temperature control apparatus and method for operating a reduction rolling mill
US3483721A (en) * 1966-12-30 1969-12-16 Automation Ind Inc Material tester
US5027634A (en) * 1990-02-28 1991-07-02 Granco-Clark, Inc. Solutionizing taper quench

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GB977485A (en) 1964-12-09
ES291037A1 (es) 1964-03-01
DE1293114B (de) 1969-04-24
BE636442A (de)

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