US2035252A - Method of manufacturing sheets - Google Patents

Description

March 24, 1936. R. J. WEAN METHOD OF MANUFACTURING SHEETS Filed Oct. :1; 1951 5 Sheets-Sheet l INVENTOR Mmh24, 1936. j R. J. WEAN 2,035,252

METHOD OF MANUFACTURING SHEETS Filed Oct. 31, 1951 5 Sheets-Sheet 2 INVENTOR .WM Z1 2222222 4 m 3M 1M.

March 24, 1936. R. J. WEAN METHOD OF MANUFACTURING SHEETS 5 Sheets-Sheet 4 Filed ()Qt. 31, 1951 INVENTOR a.

March 24, 1936. R J. WEAN METHOD OF MANUFACTURING SHEETS Filed Oct. 51; 1951 5 SheetsSheet 5 INVENTOR EQBMO atented Mar. 24, 1936 UNITED- STATES 2,035,252 METHOD or MANUFACTURING SHEETS Raymond .J. Wean,.Warren, ()hio, assignor to The Wean Engineering Company, Incorporated, Warren, Ohio, a corporation of Ohio Application October 31, 1931, Serial No. 572,294

16 Claims.

My invention relates to a method of making sheets, for example, steel sheets, and also to apparatus adapted to carry out the method.

This application is a continuation in part of my copending application serial No. 482,213 filed September 16, 1930, for Improvement in continuous heating furnaces. Y Y In accordance with a new manufacturing practice described and claimed in my U. S. Patent No. 1,871,102, granted August 9, 1932, for Method and apparatus for' making sheets, steel sheets are made from sheet bars as follows: The bars are first passed through a bar heating furnace and than through the roughing rolls. The initial rolling operation when completed converts the bars into breakdowns. The partially elongated breakdowns are then passed through a second.

furnace in pairs for reheating and. rerolling in the finishing'rolls. The finishing roll operation converts the breakdowns into sheets and they are thereupon doubled and returned to the en-- trance of the second furnace for further reheating in packs followed by a final rolling operation. Since the same furnace is employed for heating matched pairs of breakdowns and doubled packs of sheets, it is apparent that there is considerable likelihood of congestion at the en-' trance to the furnace. A more serious objection, I however, is that the pairs and packs each have their own optimum rolling temperature, and, since it is necessary that pairs and packs be passedthrough the furnace alternately in order to keep up the flow of production, it is impossi i ble, under present practice, to heat both packs and pairs to the best rolling temperature.

Obviously, if packs and pairs alternately are heated in the same furnace by passing them therethrough at the same rateof speed, which is necessary since only a single conveyor has heretofore been provided in the furnace, the final temperature of both pairs and packs is a compromise betweenthe bestitemperatures for both. Another factor contributing to this difiiculty is that the breakdowns are comparatively cold when'they enter the pack-heating furnace. The packs, however, are at a considerably higher temperature than the pairs: and, therefore, are heated more rapidly to thefinal tempera D ture, with the possibility of overheating unless extreme care is exercised.

A still further objection to the present method of operation is that it is very inflexible as to mill rolling schedules. In other. words, the finishing mill must take the material as it comes irom the place of the invention disclosed in the present 55 furnace, usually alternating packs and pairs, regardless of the production required.

I have overcome the aforementioned objections to the present methods and apparatus for making sheets by providing separate heating chambers in the pack heating furnace for the packs and pairs, with independently controllable burners for; heating and conveyors for passing material therethrough. The chambers for heating the pairs and packs separately are formed by building a central division wall in a unitary furnace chamber of sufiicient width for the purpose. The burners of the two chambers may be independently controlled to give the required final temperature to the material passing therethrough, and the speed of operation of the conveyors .may be similarly adjusted to prevent overheating and to insure the desired operating conditions. .The independent conveyors also'permit material to be discharged selectively from either thepack chamber or the pair chamber, depending upon the mill rolling schedule.

The packs and pairs may thus be heated proportionately, since the pairs, being cold require a greater amount of heat than the packs which retain a considerable proportion of their former heat. The twin chambers of the furnace for heating packs and pairs separately are arranged to supply material to the same stand of finishing rolls. The congestion at the entrance of-the pack heating furnace which is now experienced is eliminated. I

For a more complete understanding of the invention, reference is made to the accompanying drawings illustrating a present preferred embodi-' merit-of the invention, as well as a modification thereof.

In the drawings, I Figure 1 is a sectional view through one type of furnace by which the invention may be practiced, taken on a horizontal plane,partly broken away and showing portions of the apparatus diagrammatically;

Figure 2 is a longitudinal sectional view along the lineIIII of Figure l;

Figure 3 is a view similar to Figure 1, showing the preferred form of theinvention;

Figure 4 is a sectional view along the line IV-IV of Figure 3; and

Fig. 5. is a diagrammatic plan view of a sheet metal adapted for the practice of my invention.

"The method and apparatus for making sheets found in my Patent 1,871,102 above referred to will first be briefly explained in order that the application may be clearly understood. As shown in Fig. a bar heating furnace B operates to deliver bars heated to the proper temperature to roughing rolls E. The bars are passed between the roughing rolls E a sufflcient number of times to partially elongate the bars and con-. vert them into breakdowns. As is usual in the art, the breakdowns may either be matched and temperature for rolling in a furnace F, the pairs or doubles being delivered from this furnace to the finishing rolls G. After the gauge of the sheets has been reduced by passing the packs between the finishing rolls G, the packs, if not suihciently reduced in gauge, may be doubled inthe doubler D and returned by way of the conveyor R to the entrance end of the furnace F. My invention resides in improvements in this portion of the rolling operation, namely, the portion of the operation following the rolling in the roughing rolls E, and resides more particularly in the preparation of the packs forthe finishing rolls G.

Referring in detail to Figures 1 to 4 inclusive of the drawings, a furnace chamber I0 is composed of a wall ll of refractory brick, enclosed within a structural framework l2. Offset burner chambers l3 are provided in the side walls of the furnace. Burners l4 are fitted in the bumer' chambers and connected to any suitable fuel supply. Baiiies |5 prevent the flames from the burners from playing directly on the material in the fm'nace.

The ends of the furnace II are open but are adapted to be closed by doors 13. Chain conveyors l1 and I3 are adapted to traverse the furnace from the charging end to the discharge end thereof, in the direction indicated by the arrows. Each conveyor consists of a pair of chains l3 having rollers 26 pivoted between the links thereof. Flights, or material engaging carriers 2|, are secured to the .chains at intervals and are adapted to pass through slots in the tile forming the fioor of the furnace. In this way, the body of the conveyor is protected from the heat of the furnace. Rails 22 are provided below the furnace floor for supporting the rolls 20, and similar rails 23 are located below the fumacefor the same purpose.

The chains I! extend between a driving sprocket 24 and an idlingsprocket 25. .The driving sprockets 24 are secured to shafts 25 rotatably mounted in fixed bearings 26a. Driving means for the shaft 23 of the conveyor II include a motor 2'| connected to a reducing gear 23. The reducing gear is coupled to the shaft 23 by a coupling 23 A similar mctor 33 and reducing gear 3| are coupled to the shaft 26 of the .conveyor l3 through a coupling 32.

A clutch 33 ofany desired-type may be provided for rigidly connecting the shafts 23 of the conveyors l1 and I3 when it is desired that the latteroperate as a single unit.

The motor 21 is provided with a suitable speed controlling device indicated at 34. The details of the speed control device are, of com'se-,.dependent upon the type and characteristics of motor employed, and it is to be understood that any arrangement of these elementsmay be reaoaaaas sortedto. As an example, it might be assumed that the motors 21 and 30 are direct current shunt wound motors, and that the speed control device 34 consists of a rheostat connected in the circuit of the field winding'of the motor. In such case, suitable starting connections will, of course, be provided for the motor armature circuit.

The speed control device 34 for the motor 21 is duplicated for the 'motor 30 at 35. A third speed control device 36 may be provided for controlling both motors simultaneously, but it is obvious that one of the devices '34 and 35 may be employed for this purpose. The devices 34 and 35 are connected directly between their respective motors and a supply circuit 31, to

which the device 36 is also connected. The de-..

The idler sprockets 25 are each mounted on a shaft 42 journaled in bearing blocks 43. The bearing blocks 43 are slidable longitudinally on guides 44. A yoke 45 secured to the bearing blocks supporting each shaft 42 is connected to one arm of a bell crank 46 pivoted at 41. The

other arm of the bell crank carries a counterweight 43. It will be obvious that this construction permits longitudinal movement of the sprockets 25 to maintain the conveyor chains 19 taut.

When it .is desired to operate the conveyors synchronously, the clutch-33 may be connected, the speed control devices 34 and 35 set in the off position and the switches 40 and 4| closed. The operation of the motors 21 and 33 is then under control of the device 36, although the latter may be omitted and either of the devices 34 or 35 used for this purpose, the other being set in the off position. Aslong as the clutch 33 is engaged and the motors 21 and 33 operate under the control of a single speed control device, it is obvious that the conveyors will move synchronously through the furnace.

If it is desired to operate the conveyors independently, the clutch 33 may be disengaged and the motors 21 and 33 replaced under the controlof their individual speed controllers 34 or 35. The speed of each motor may then be adjusted independently to operate the conveyors and I3 at any desired speeds. This makes it possible to pass packs and pairs through the furnace on separate conveyors at difierent rates. The packs and pairs will thereby be subjected to' the heating action of the furnace for different periods of time, which can be adjusted to insure that the final temperature of the material as it emerges from the furnace is at the proper point. On leaving the furnace, the material passes to the finishing roll stand indicated diagrammatically at 56. Since the conveyors are independently controlled, it is possible to obtain not only proportional heating of the different classes of material but also selective discharge thereof. It is not necessary, for example, for the material to be fed to the rolls in the order in which it comes from the furnace, but packs or pairs can be rolled successively for certain Although the furnace shown in Figures '1 and 2 serves very well to provide proportional heating and selective discharge of the material passed therethrough, I find that the desired results may be more effectively obtained by the use of a furnace-of the 'type shown in Figures 3 and 4. This furnace is similar to that shown in Figures 1 and .2 and comprises a refractory "housing 5! enclosed within a structural frame 52. The furnace is provided with a hearth 53 andv a central partition wall 54. The wall 54 -divides the interior of the furnace housing into twin furnaces or'heating chambers. Each chamber has a bu'nier 55 and a baiile 56 asin the furnace of Figures 1 and 2. Separate conveyors Hand '58 are also provided in'the twin chambers. The conveyors extend continuously through the furnace rising above the hearth-as shown in Fig'ure'- 4, and are of substantially the same construction as those shown in Figures land 2. The conveyors serve, obviously to feed material into the entrance end 59, through the heating chambers and out the discharge end 60. 'From the discharge end 61!, the material is passed to the finishing rolls Si by any convenient handling mechanism. The details of the conveyor structure are the same as those previously described, 'so that a repetition of the description is not necessary. Independent motor drives 62 and 63- are provided for the conveyors 51 and 58. These drives are of the variable speed type, but none housing.

\ dependent of the conditions in the adjoining The operationof the furnace shown in Figures 3 and 4 is similar to that of the furnace in Figures 1 and 2. The packs and pairs are fed separately to the chambers of the furnace on the conveyors 5! and 58. The center wall 58 makes it possible to control the temperature in the two chambers of the furnace in any desired manner. The temperature conditions in one chamber, by reason of the wall 56, are inchamber. The independent control of the conveyors, furthermore, facilitates the proportional heating of packs and pairs separately and the selective discharge thereof from the furnace.

It will be apparent that the method and apparatus described herein-possess numerous important advantages over presentpractice. The congestion at the entrance end of the pack heating furnace which has been experienced heretofore is avoided, because the capacity of the furnace disclosed herein is practically double that of the single width furnaces used heretofore. The difierence between the temperature of the relatively cool breakdowns from the roughing mill and the temperature of the packs from the finishing mill and doubler can readily be taken care of by adjusting the burners of the chamber receiving the breakdowns to produce a higher temperature therein than in the chamber receiving packs. The speed of travel through the furnace chambers may also be adjusted so that the cool breakdowns have a longer heating period than the preheated packs. The exact temperature requirements of each class of material can thus be met with the requisite degree of precision. The independent drive for the two conveyors in the furnace permits the mill operation to be altered to suit conditions without any rigidity imposed by the method of heating the different classes of material. In other words, if it is desired to roll packs only for a while, this can be done by stopping the pair conveyor, and the reverse is equally possible.

Although I have illustrated and described herein but two embodiments of the invention, it will be apparent that it may be practiced in other ways and by the use of other equipment than herein disclosed. Such changes in the apparatus and method described may, however, be made without departing from the spirit of the invention as defined in the appendedclaims.

1. In a continuous method of rolling sheet bars into sheets wherein the material is advanced continuously through a bar heating -furnace, then passed between roughing --rolls to partially elongate the same to breakdowns and the breakdowns then reduced to the desired gauge-by reheating and passing between finishing rolls, the improved steps consisting of continuously advancing breakdowns assembled .in runover packs through a heating chamber to a point adjacent a rolling mill, subjecting the packs to a runover pass in the mill, doubling the packs, thereafter continuously advancing the doubled packs through a second heating chamber to a point adjacent the same mill, finish rolling the doubled packs in said mill, the rolling of doubled packs being interspersed with the rollingof runover packs, and maintaining the temperatures in the two chambers at the same or different temperatures as selected for imparting the proper amount of heat to the two series of packs.

2. The method of claim 1 wherein the runover packs and the finishing packs are fed through their respective heating chambers at different rates.

3. The method of claim 1 wherein the temperature of the runover packs on being discharged from their heating chamber differs from that of the finishing packs as discharged from their chamber.

4. In a continuous method of rolling sheet bars into sheets wherein the bars are passed through a continuous bar heating furnace, then subjected to a suflicient number of passes be-' tween roughing rolls to partially elongate the bars to breakdowns, the breakdowns then reheated and reduced to the desired gauge by passing betweenv finishing rolls, the improved steps consisting of continuously matched breakdowns forming runover packs through a heating chamber into proximity to a rolling mill, rolling the runover packs in the mill to form finishing packs, thereafter continuously advancing the finishingpacks through a second heating chamber into proximity to thesame mill, and rolling the reheated finishing packs in said mill, the rollingof runover and finishing packs being interspersed.

5. The method defined by claim 4 characterized by the step of controlling the speed of advancing the runover and finishing packs through their heating chambers respectively to regulate the temperature at which the packs are disadvancing charged from the chambers for rolling in the peratures in'the chambers -i 'or heating runover and finishing packs-respectively;

- 7. The methodzdefined'by claim 4 characterized by maintaining the temperatures in the two chambers at the same or difierent temperatures as. selected by the operatorior, raising the temperature of the respective series oi packsto the desired value for rolling.

8. In a continuous method of rolling sheet bars into' sheets wherein the bars are passed through a continuous bar heating furnace, then subjected to a sufficient number of passes betweenroughingxrolls to partially elongate the bars-to breakdownarthe breakdowns then reheated and reduced to the desired gauge by passing between finishing rolls, the improved steps consisting of continuously advancing matched ing the runover packs which have been rolled to form finishing packs through said second chamber.

' 9. A method of rolling sheets which consists in maintaining sheet material in different stages of completion at diil'erent temperatures, in passing material in different stages of completion through a mill stand, to perform a rolling operation thereon, and in periodically delivering material of a different temperature to such stand for the purpose of maintaining a substantial continuity in the delivery of finished material from said stand.

10. In the operation of rolling sheets, the step of heating partially finished material, in at least two furnaces, maintained at different temperatures, successively delivering sheet material in one stage 01' completion to one such furnace and delivering material in a different stage of com pletion to the other such furnace, periodically delivering material from each such furnace to a single hot mill, performing a rolling operation on material so delivered insaid hot mill, whereby sheet material in different stages of completion is successively delivered to said mill.

. RAYMOND J. WEAN.

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