US3740982A

US3740982A - Temperature and shape control system for rolling mill rolls

Info

Publication number: US3740982A
Application number: US00195684A
Authority: US
Inventors: R Hacker; Coy W Mc
Original assignee: Timken Co
Current assignee: Timken Co
Priority date: 1971-11-04
Filing date: 1971-11-04
Publication date: 1973-06-26
Anticipated expiration: 1990-06-26
Also published as: BE787636A; AU4502372A; CA957878A; JPS5010829B2; GB1404663A; AU451158B2; JPS4853955A; DE2240204A1; IT961979B

Abstract

A temperature and shape control system for rolling mill rolls operable to extract heat or add heat to the roll ends of the back-up rolls to produce and maintain a heat balance and temperature gradient across the width of the roll bodies to maintain the desired roll shape for determining and improving the flatness of the product being produced in the rolling mill.

Description

United States Patent Hacker et al.

TEMPERATURE AND SHAPE CONTROL SYSTEM FOR ROLLING MILL ROLLS Robert W. Hacker, Massillon; Wyn E. McCoy, Canton, both of Ohio The Timken Company, Canton, Ohio Nov. 4, 1971 Inventors:

Assignee:

F iled:

Appl. No.:

US. Cl. 72/13, 72/201 Int. Cl B2lb 37/10, B21b 27/06 Field of Search 72/13, 200, 237,

References Cited UNITED STATES PATENTS 8/1903 Thompson 72/200 4/1960 Von Der l-leide 72/200 10/1934 Clark 72/200 1451 June 26,1973

1,982,571 11/1934 Clark 72/201 1,936,582 11/1933 Clapp et a]. 72/200 4 2,431,473 10/1947 Flynn 257/2 1,988,679 1/1935 Badlam 72/201 2,692,118 10/1954 Holloway 72/200 x 2,243,010 5/1941 lversen 72/200 3,604,237 9/1971 Kawanami 72/201 Primary Examiner-Milton S. Mehr Attorney-Frederick M. Woodruff et a1.

ABSTRACT A temperature and shape control system for rolling mill rolls operable to extract heat or add heat to the roll ends of the back-up rolls to produce and maintain a heat balance and temperature gradient across the width of the roll bodies to maintain the desired roll shape for determining and improving the flatness of the product being produced in the rolling mill.

7 Claims, 6 Drawing Figures PATENTEUJUN 26 I973 SIEHUUC FIG 4 TEMPERATURE AND SHAPE CONTROL SYSTEM FOR ROLLING MILL ROLLS BRIEF DESCRIPTION OF THE INVENTION This invention relates to improvements in temperature and shape control provisions for rolling mills and is especially directed to improvements in maintaining and controlling the heat balance and temperature gradients across the width of the roll bodies by controlling roll neck temperatures.

In high speed strip mills a major problem is the control of the strip flatness. Flatness is effected by many variables which are continuously changing. For example, flatness varies with changes in the material being rolled, the strip thickness and width, the amount of re duction, the temperature and hardness characetistics of the strip passing between the rolls, the temperature of the rolls themselves, the degree of roll wear, and the degree of tension exerted on the strip during its passage through the rolling mill. It is an extremely difficult problem to coordinate all of the variables so as to produce a substantially uniform flatness throughout the strip as it comes out of the rolling mill. A number of variables have been referred to above and it is known from actual practice that some of these variables change during a days operation of the rolling mill. Others change gradually from one end of the strip coil to the other, some of the variables make abrupt changes from one coil to another andsome variables make abrupt changes within a single coil.

It is presently known that methodsused to correct some of these variables include back-up roll and work roll bending to a predetermined curvature, the application of cooling sprays and work roll and/r backup roll crowns.

It is a general object of the present invention to provide a temperature and shape control system for rolling mill rolls which may have utility by itself, as well as in combination with other means of known character for controlling shape.

It is an object of the present invention to provide improved shape control for rolling mill rolls through the control of the heat at the bearings which support the roll necks so that the strip flatness can be made substantially constant across its width during strip rolling operations.

It is a further object of the present invention to provide an improved system for controlling the shape of rolling mill rolls by the utilization of a heat transfer fluid medium applied to the roll necks in the critical areas thereof supported by the bearings.

Still another object of the present invention is to provide the improvements heretofore stated and to combine therewith means to control the heat balance and temperature gradient across the rolling mill rolls by modulating the flow of the heat transfer fluid.

Other objects and advantages of the present invention will be set forth hereinafter in more detail, and it is intended to include the various elements, parts and components which are particularly set forth and described.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is best seen in connection with the accompanying drawings which set forth presently preferred embodiments, and wherein:

FIG. 1 is a somewhat schematic end elevational side view of a rolling mill having work rolls and back-up rolls arranged in a generally conventional manner and wherein portions of the presently improved temperature and shape control system may be seen;

FIG. 2 is a fragmentary and partial sectional elevational view of the rolling mill taken at line 2-2 of FIG. I particularly showing the means by which the temperature of the back-up roll necks may be controlled in accordance with this invention;

FIG. 3 is a fragmentary and greatly enlarged sectional view along the line 3-3 in FIG. 1 to show details of a roll neck and bearing support therefor with a typical temperature and shape control system;

FIG. 4 is a fragmentary end elevational view of a back-up roll chock provided with a modified temperature and shape control system, the view being typical of both back-up rolls of the rolling mill shown in FIG.

FIG. 5 is a fragmentary sectional view taken at line 5-5 in FIG. 4', and

FIG. 6 is a fragmentary view of means to control the fluid circulating valves, such as the character of means shown in FIGS. 1 and 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to FIGS. 1 and 2 of the drawings, there is shown a preferred rolling mill arrangement which comprises a typical four-high rolling mill stand having the usual pair of mill housings, one of which is seen at 10. The mill is used to roll flat strip materials S. Since there are a pair of housings for each stand, it is understood that the description of one housing will apply equally to the other. The mill housing 10 supports the necks of a pair of

work rolls

11 and 12 and a pair of back-up rolls l3 and 14. Work roll 11 is backed up by roll 13 and work roll 12 is backed up by roll 14. The work rolls l1 and 12 are suitably mounted in chocks l5 and 16 respectively, and the back-up rolls are slidably mounted in

chocks

17 and 18 so as to be vertically adjustable for back-up roll and for work roll diameter variations. The adjustable chock 17 supports the backup roll 13 and the embodiment shown enables both the work roll 11 and its back-up roll 13 to be moved simultaneously relative to the work roll 12 and its back-up roll 14 for thickness control of the strip being rolled. The work roll 12 has its chock 16 suitably mounted in the supporting chock 18 for the back-up roll 14, and in this case the chock 18 is rested in the mill housing 10 on a suitable bearing plate 19. The means for adjusting the

work rolls

11 and 12 is generally shown at the adjusting screw 20 operatively mounted in the upper end of the mill housing 10 and connected'in a suitable manner to the thrust bearing unit 21 engaged on the upper end of the chock 17 for the upper back-up roll 13 and work roll 11.

Referring now to FIGS. 2 and 3, it can be seen that the upper back-up roll 13 is typically provided with roll necks 13a, each of which is operatively mounted in a four row tapered roller bearing 22 engaged between the roll neck 13a and the chock 17 in mill housings 10. The back-up roll 14 is mounted in a similar manner at necks 14a so that the view of FIG. 3 will suffice for all of the roll neck mountings.

The initial set up for the mill is to have the work rolls 11 and 12 and the back-up rolls l3 and 14 cylindrical or with some preconceived special crown which will tend to counteract deformations imposed by normal rolling loads and thereby produce a flat strip. The achievement sought is to maintain this initial setting by counteracting the effects of temperature and wear or to modify the initial setting if and when required to produce a flatter strip. It has been found that heat exchange fluid circulated in the back-up roll bearing areas will keep the initial desired shape of such rolls over substantially all mill operating conditions. The heat exchange fluid is circulated in such a way that a balance is obtained between the heat picked up from the work reduction and the heat picked up from the baring load reaction.

In the view of FIGS. 2 and 3 the temperature control fluid for the roll neck 13a is supplied through a swivel coupling 25 which receives the supply of control fluid which is directed by a conduit 26 at opposite sides of the stand axially through the roll neck 13a and into the inner end portion of bore 27 (FIG. 3) in the back-up roll 13. The tube 26 penetrates the axial bore 27 and is smaller in diameter so as to provide an annular passage 28 for the fluid return flow outside of an enclosing sleeve 29 to isolate the return fluid in the annular passage 28 from the supply fluid within the tube 26. The return fluid is conducted away through conduit 30 which is associated with or as a part of the fitting 25.

In FIG. 1 a combined complete system is disclosed, with some portions shown in schematic outline. The showing includes a roll neck recirculating system where the fluid is moved by a pump 31 through a filter 31A into branch conduits 32 at each side, and the fluid flows out through the T-fittings. One such T-fitting 33 (FIG. 1) conducts the fluid into a fitting 25 of the character shown in FIG. 3. The return flow is conducted by lines 30 to a return conduit 34 at T-fittings 35, and from conduit 34 the fluid flows to a heat exchanger unit 37, and thence to the pump 31 for recirculation. The return fluid flow to conduit 34 from each fitting 25 is controlled by a suitable valve 38 which is modulated under the control response of temperature measuring thermocouple probes 39 mounted in the chocks 17 and 18 (FIG. 2) adjacent he roll neck bearings 22 so as to be responsive to the temperature at these hearings.

Also, as may be seen in FIG. 1, part of the combined system includes a system where the fluid from conduit 32 flows from T-flttings 40 to conduits 41 respectively connected to jacket spaces 42 in the chocks l7 and 18. From the jacket spaces 42 the fluid is conducted by cross-over passages 43 to jacket spaces 44 at the opposite sides of the roll neck bearings 22 where the fluid exits at conduits 45 to the return conduit 34 through individual flow regulating valves 36 to T-fittings 47 in return line 34. The valves 36 may be manually regulated, but in the view shown they are automatically controlled by means 48 responsive through lead 48 to the temperature at the thermocouple probes 39 used to control the valves 38 in the roll neck heat control system. In the manner shown, fluid is circulated into the roll necks 13a and through the chocks around the neck bearings 22 so that the temperature across the back-up rolls l3 and 14 is controlled to avoid roll distortion due to the heat of rolling the strip material S or heat from the hearings or seals, thereby assuring flatness and accuracy of the thickness of the strip material S.

There is shown in FIGS. 4 and a modified system for temperature control of the roll neck bearings in the chock 17 for the upper back-up roll 13. In these views a header manifold 50 receives the fluid flow at end 51. The manifold is provided with a plurality of (4 being seen) outlet conduits 52 (FIG. 5) which extend axially into bores 53 in the chock 17 along side the roll neck bearings. The conduits 52 are smaller than the bore so as to form an annular flow passage 54 which leads into the return housing 55 so that the fluid may flow out at nipple 56 and into the return manifold 57 for exit at the manifold outlet end 58. The inlet end 51 of manifold 50 is adapted to be connected at T-fitting 40 by conduit 41 (FIG. 1) and the end 58 of the manifold 57 is connected to T-fitting 47 by conduit 45 (FIG. 1).

The assembly shown in FIG. 4 also includes the provision of

fluid circulating means

60 and 61 adjacent the roll neck bearing but below and at each side of the axis of the roll neck at approximately 45 from each side of the vertical. The devices at 60 and 61 are each made up in a manner similar to the assembly shown in FIG. 5 except that the fluid inlet taps 62 and 63 respectively are laterally and downwardly directed while the fluid discharge taps 64 and 65 come out of the

fittings

50 and 51 respectively in an axial direction. In the view of FIG. 4 the modified flow distribution system is shown in connection with the upper back-up roll neck where the reaction transmitted into the back-up roll from the upper work roll is predominately vertically upwardly. Therefore, the fluid supply and

exhaust manifold

50 and 57 are connected to distribute the temperature control fluid over the area of maximum load reaction because it is in this area where the bearing loads generate the greatest heat.

It should be understood in looking at FIG. 4 that the same fluid flow system when applied to the roll neck bearings for the lower back-up roll 14 will be just the opposite to the fluid flow arrangement shown in FIG. 4. That is to say, the

manifolds

50 and 57 will be at the bottom and the

fluid flow devices

60 and 61 will be at the top, with all of the parts in the same relative changed positions.

In high speed strip rolling means a major problem as has been pointed out, is the difficulty of controlling the strip flatness because of the continuous change in the variables which affect flatness. It is already noted that flatness varies with such things as the character of the material being rolled, the strip thickness and width as well as the amount of reduction being produced, the variations in strip temperature and hardness as well as the tension applied to the strip, and the temperature rise which occurs in the rolls and in the roll bearings. It is known that some of the variables mentioned change more or less gradually throughout the run period of the rolling mill, some changes occur gradually between the starting and finishing ends of the coil strip, while still others may change abruptly from one coil strip to another. It is the intention of the present disclosure to set forth a temperature and shape control system where the heat generated in the back-up rolls is balanced along its length by introducing or removing heat from the bearings and the bearing housing at the ends where the roll necks are mounted. The present system may be operated to take away heat from the bearing areas or add heat to the roll ends so as to produce th desired heat balance and temperature characteristics across the width of the back-up rolls. It is preferred herein to implement the disclosure in terms of the circulation of a heat control fluid such as water and to provide control valves which are thermostatically modulated in terms of the desired heat levels to be maintained at the critical areas of the rolling mill. While the present system has been disclosed in connection with controlling the temperature characteristics across the length of back-up rolls, it is understood that provisions similar to those disclosed in FIGS. 2, 3 and 4 may be applied to the roll necks at the opposite ends of the upper and lower work rolls, but such disclosure has been understandably omitted so as to simplify the description and drawings.

In the present disclosure a system has been described for controlling heat in the back-up rolls l3 and 14. The heat in these rolls (FIG. 2) is introduced or removed by the bearings 22 at the

necks

13a and 14a or at the center of the rolls l3 and 14 by the product S being rolled.

The heat balance in each of the back-

up roll necks

13a and 14a (FIGS. 1 and 2) is subject to the control effected by temperature sensing thermocouple means 39. Each thermocouple means 39 is connected by a lead 49 into an electrical buss in the protective tube 66. The lead 49 is, in each instance, electrically united with lead 49' which connects to a suitable control mechanism generally shown at 46. The mechanism 46 is connected to the adjacent valve 38 so that the temperature in the roll neck can be regulated by flow of the heat transfer fluid through conduit 30. Thus, the thermocouple 39 by measuring the temperature of a suitable place in the

chock

17 and 18 modulates the mechanism 46 which opens or closes valve 38 in response tothe desired heat transfer to maintain accurate results in rolling the work strip S. The general mechanism of 46 may be a Leeds and Northrup series 10260 drive mechanism for an electric valve controller which, in turn, may be a Leeds and Northrup Electromax III universal controller forapplications with thermocouples 39, or an equivalent. The latter operates valve 38.

In FIG. 1 there is shown a system for controlling the heat balance in the roll neck bearings as the load on the bearings contributes to the generation of heat. In this system, the heat transfer fluid supplied from conduits 41, exits at conduits 45 to valves 36 and to the return conduit 34. The valves 36 are each under the control of mechanism 48 which is similar to mechanism 46 described above. As before, the thermocouples 39 are electrically connected into the buss in tube 66, and a lead 48' extends therefrom for connection at mechanism 48. It is understood that when the thermocuples vary from a predetermined setting heat balance is ei ther retained by the closing of one or more of the

valves

36 and 38, or by the opening of one or more of

valves

36 and 38. Of course, the

valves

36 and 38 can be modulated between open and closed positions.

In FIG. 6 there is shown an arrangement of components which constitute the mechanism of components 46 heretofore-described. For example, lead 49 and 49' from a thermocouple 39 is connected to the valve controller device VC that operates a prime mover PM connected by suitable links to the valve 38. The valve 38 may control the flow of heat exchange fluid from line 30 to line 34 which leads back to the heat exchanger 37. The devices VC and PM may be Leeds and Northrup components heretofore identified in the description of FIGS. 1 and 2.

The present system, therefor, includes means whereby heat may be taken away from or added to the roll ends or necks to produce or maintain a desired heat balance and temperature gradient across the width of the roll, and therebymaintain the desired roll shape which determines the flatness of the product S being rolled. While the disclosure has shown the system applied only to the back-up rolls it is understood the same system is adapatable to the work rolls.

What is claimed is: 1. Apparatus to control the heat balance and temperature gradient across the rolls of a mill for rolling strip material to a uniform thickness, said apparatus includmg:

a. cooperating strip material work rolls and back-up rolls engaged with said work rolls, said rolls having necks for the operative support thereof, b. vertical housings formed with windows, 0. chocks slidably mounted in said windows and bearings carried by said chocks 1. said roll necks being supported in said bearings, d. a fluid circulating system connected into said chocks adjacent said roll neck bearings, said system having 1. fluid heat exchanger means and circulating pump means in series connection and 2. circulating flow control means connected into said system in advance of said heat exchanger, said control means being responsive to temperature adjacent said roll necks to selectively increase and decrease the fluid circulation in said chocks and bearings and balance the heat rise in said back-up rolls.

2. The apparatus of claim 1 wherein said circulating flow control means includes thermostatically controlled valve means adjacent each of said roll neck bearings, said valve means individually regulating the roll neck bearing heat rise in accordance with predetermined heat balance requirements of each'roll neck bearing.

3. The apparatus of claim 1 wherein said circulating flow control means includes temperature sensing means adjacent said roll neck bearings, valve means inserted in said fluid circulating system, and temperature controller means connected between said temperature sensing means and said valve means whereby the heat 'rise in said bearings is balanced across said work rolls.

5. The apparatus of claim 3, wherein said circulating flow control means includes thermostatically controlled valve means adjacent each of said roll neck bearings.

6. In rolling mill apparatus including a framework and work and back-up rolls operably mounted by roll necks and supporting bearings in said framework in a four-high roll assembly; the improvement of a roll shape and temperature control system for said back-up rolls comprising, fluid flow passage forming means in said roll necks, separate fluid flow passage forming means surrounding said bearings supporting said roll necks, conduits connected to both said passage forming means to supply fluid to and receive fluid from said passage forming means, heat exchange means connected to said fluid supply and receiving conduit means, pump means disposed in said system to cause fluid flow, heat responsive means in the framework carrying said'bearings, and valve means in said fluid receiving conduit connections, said valve means being connected to said heat responsive means and operated thereby to modulate the fluid flow in both said fluid flow passage forming means and cause said back-up -rolls to operate at a predetermined temperature and shape in response to the temperature conditions in said roll necks and supporting bearings.

7. In rolling mill apparatus the improved combination of means to control the temperature and shape of rolling mill rolls, comprising a pair of work rolls to produce strip material of uniform thickness and width, a backup roll in rolling engagement with each work roll, each back-up roll having roll necks, bearings supporting said roll necks, and means to control the heat generated in said roll necks to obtain heat balance across the length of said back-up rolls, said control means including fluid flow means connected into each roll neck to circulate fluid internally of each roll neck, fluid conducting jackets externally adjacent said roll necks and bearings, conduits connected to said internal flow means and to said external jackets, heat transfer fluid contained in said conduits, pump means operative to circulate said fluid through said conduits and jackets, heat exchanger means connected into said conduits and pump means, temperature measuring means adjacnet said roll neck bearing supporting means responsive to temperature at said bearing means, and valve means responsive to said temperature measuring means to modulate said fluid circulation selectively to add and withdraw heat at said roll necks.

t i I i

Claims

1. Apparatus to control the heat balance and temperature gradient across the rolls of a mill for rolling strip material to a uniform thickness, said apparatus including: a. cooperating strip material work rolls and back-up rolls engaged with said work rolls, said rolls having necks for the operative support thereof, b. vertical housings formed with windows, c. chocks slidably mounted in said windows and bearings carried by said chocks 1. said roll necks being supported in said bearings, d. a fluid circulating system connected into said chocks adjacent said roll neck bearings, said system having 1. fluid heat exchanger means and circulating pump means in series connection and 2. circulating flow control means connected into said system in advance of said heat exchanger, said control means being responsive to temperature adjacent said roll necks to selectively increase and decrease the fluid circulation in said chocks and bearings and balance the heat rise in said back-up rolls.

2. The apparatus of claim 1 wherein said circulating flow control means includes thermostatically controlled valve means adjacent each of said roll neck bearings, sAid valve means individually regulating the roll neck bearing heat rise in accordance with predetermined heat balance requirements of each roll neck bearing.

2. circulating flow control means connected into said system in advance of said heat exchanger, said control means being responsive to temperature adjacent said roll necks to selectively increase and decrease the fluid circulation in said chocks and bearings and balance the heat rise in said back-up rolls.

3. The apparatus of claim 1 wherein said circulating flow control means includes temperature sensing means adjacent said roll neck bearings, valve means inserted in said fluid circulating system, and temperature controller means connected between said temperature sensing means and said valve means whereby the heat rise in said bearings is balanced across said work rolls.

4. The apparatus of claim 3, wherein said valve means includes prime mover drive means, and said temperature controller modulates said drive means.

6. In rolling mill apparatus including a framework and work and back-up rolls operably mounted by roll necks and supporting bearings in said framework in a four-high roll assembly; the improvement of a roll shape and temperature control system for said back-up rolls comprising, fluid flow passage forming means in said roll necks, separate fluid flow passage forming means surrounding said bearings supporting said roll necks, conduits connected to both said passage forming means to supply fluid to and receive fluid from said passage forming means, heat exchange means connected to said fluid supply and receiving conduit means, pump means disposed in said system to cause fluid flow, heat responsive means in the framework carrying said bearings, and valve means in said fluid receiving conduit connections, said valve means being connected to said heat responsive means and operated thereby to modulate the fluid flow in both said fluid flow passage forming means and cause said back-up rolls to operate at a predetermined temperature and shape in response to the temperature conditions in said roll necks and supporting bearings.

7. In rolling mill apparatus the improved combination of means to control the temperature and shape of rolling mill rolls, comprising a pair of work rolls to produce strip material of uniform thickness and width, a back-up roll in rolling engagement with each work roll, each back-up roll having roll necks, bearings supporting said roll necks, and means to control the heat generated in said roll necks to obtain heat balance across the length of said back-up rolls, said control means including fluid flow means connected into each roll neck to circulate fluid internally of each roll neck, fluid conducting jackets externally adjacent said roll necks and bearings, conduits connected to said internal flow means and to said external jackets, heat transfer fluid contained in said conduits, pump means operative to circulate said fluid through said conduits and jackets, heat exchanger means connected into said conduits and pump means, temperature measuring means adjacnet said roll neck bearing supporting means responsive to temperature at said bearing means, and valve means responsive to said temperature measuring means to modulate said fluid circulation selectively to add and withdraw heat at said roll necks.