US2143554A

US2143554A - Metal rolling process

Info

Publication number: US2143554A
Application number: US105922A
Authority: US
Inventors: Henry L Harper
Original assignee: Aluminum Company of America
Current assignee: Howmet Aerospace Inc
Priority date: 1936-10-16
Filing date: 1936-10-16
Publication date: 1939-01-10
Anticipated expiration: 1956-01-10

Description

Jan. 10, 1939. H. 1.. HARPER 2,143,554

METAL ROLLING PROCESS Filed Oct. 16, 1956 s Sheets-Sheet 1 IIIIIIIIIIIIIIIIII/ INVENTOR.

BY fis/vz'rl. H42 56" ATTORNEY.

Jan. 10, 1939. H. L. HARPER METAL ROLLING PROCESS Filed Oct. 16, 1936 3 Sheets-Sheet 2 INVENTOR. HAM/5X1. A P55 QTTORNEY.

Jan. 10, 1939. H. HARPER METAL ROLLING PROCESS 3 Sheets-Sheet 5 Filed Oct. 16, 1936 INVENTOR #:WEXL/SQ 1 ATTO EY u n u v m lwdfi I i atente ti to ill. 10, 1939 ED STATES PATENT OFFICE METAL RULLING: PROCESS Application October 16, 1936, Serial No. 105,922

7 Claims.

This invention relates to the production of relatively thin sheet metal provided with integral longitudinal reinforcing ribs at spaced intervals, and particularly to the production of such material having a height of rib equal to several times the sheet thickness.

It is an object of this invention to provide a rolled sheet product provided with longitudinal reinforcing ribs giving a high value of section modulus as compared with its unit weight. A

further object is to provide a method for the prothe specific material herein set forth asv an ex-.

ample of a form of the invention;

Fig. 6-showsa section of one rib to an enlarged scale at' an intermediate stage of the rolling process.

Fig. '7 shows the relation of the material after the first forming roll pass to the material in the form of the initial flat slab;

Fig. 8 shows an end elevation of the mechanism used for guiding the material through the various forming roll passes;

Fig. 9 shows a vertical section through the guide mechanism shown in Fig. 8.

The structural advantages of the novel material of this invention are apparent from inspection. It may be utilized in a variety of manners, such as for forming shelves, sheet metal panels and the like, in which it is desired to have one flat surface and a high factor of structural rigidity in one direction. Previously when it was desired to produce materials having these characteristics, it has been necessary to attach reinforcing members by means of some mechanical attachment, or by welding members to one side of a flat sheet.

While a product known as washboard section has long been a standard article of commerce, the height of the ribs which have been produced in this material has seldom been more than 2 to 3 times the thickness of the plate, and as compared to weight, has only a slight increase in section modulus over that of flat sheet of identical weight. Due to the methods employed for rolling this material, only relatively narrow sections could be produced, and further, the methods inherently require a relatively close spacing of the ribs. 1

By the teachings of the present invention, it is possible to produce a plate provided with integral ribs of a height that is in excess of five times the plate thickness and of virtually any practicablearea, spaced at any desired distance apart and in material having any commercially practicable width.

The invention may be practiced in the production of such material from any of the ferrous and non-ferrous alloys susceptible to working by rollforming in either the heated or cold state, usually employed for the working of these materials. The invention is particularly described in conjunction with the production of this novel material from a workable aluminum base alloy, selected as an example because certain of the forming passes are performed in the heated state and others in the cold.

Referring to the drawings, and particularly to Figs. 1 to 5 inclusive, the consecutively numbered figures represent the successive order of the roll passes. In these figures, the reference numerals I and 2 represent the cooperating working rolls mounted in housings, not shown, and provided with means for vertical adjustment in the usual manner. The rolls are adapted to form the material shown in section. The initial material is a fiat slab, but in the first pass through the rolls its shape is changed to provide a plurality of ribs 4 and heel portions 5, for purposes to be described later, and web portions 3.

The proportions of the specific example selected for illustration is for a sheet having a web thickness of .050" and a rib height of .281". The cast ingot of aluminum base alloy was initially reduced to a slab or plate .610" in thickness. The initial dimensions of the ingot are'immaterial, but it is preferable to obtain a reduction in thickness of at least 80 per cent from the thickness of the original ingot in order to obtain a satisfactory grain structure and malleability in the slab. To further improve the metallurgical characteristics of the material, the final fiat passes were made with the material cold. The material was then re-heated to hot rolling temperature and passed through the first set of forming rolls adjusted to give a web thickness of .218", a rib height of .281" and a heel height of .281". The second pass was made giving a web thickness of .115", a rib height of .375" and a heel height of .156. The third pass gave a web thickness of .075", a rib height of .359" and a heel height of .062", The fourth pass gave a web thickness of .055", a rib thickness of .312" and a heel height of .047". The fifth pass, made with the material cold, gave the final web thickness of .050", a rib height of .281" and a flat surface on the unribbed side.

In the first pass, the rib and heel heights are the same; in the second pass, the rib height isincreased but the heel height is decreased. It is essential, in order to effect a displacement of the material from the heel over into the rib, that the width of the groove in the roll forming the heel bewider than the groove in the roll forming the rib. This is best illustrated-by referring to Fig. 6, where the vertical lines indicate the points of tangency of the outer radii forming the contour ofthe' rib and heel and the center line of the rib and heel. It is necessary that the point of tangency of the radii of the heel be at a greater distance from the center line than the point of tangency of the radii of the rib. In the final pass, the heel is completely obliterated, and all of the raised material is in the rib.

As the depth of the rib and heel is controlled by the shape of the grooves in the rolls, any

variation in roll setting afl'ects the gauge of the web only. It is essential therefore that the total rib and'heel area obtained in any pass after the first will be adaptedto give the-same degree of elongation upon rolling as the web, otherwise,

the sheet will curl as it comes out of the rolls due to the tension set up in the outer fibers by the unequal elongation.

--Other details of the pass designs, such as the selection. of the proper radii to obtain the required metal flow and the proper clearance taper on the rib to permit of easy freeing from the roll grooves, are dictated by the characteristics of the material being rolled, such as its ductility and the freeing characteristics of its surface. These details of design are well within the scope of those in the art of rolling the various metals.

The method of guiding the material Ill into the various forming roll passes is illustrated in Figs. 8 and 9. to guide the material by means of guides which engage only the edges, partly because in many.

cases the edges are rough and irregular, but more particularly for the reason that in the rolling of thin gauge material the transverse rigidity of the material is insufficient to maintain accurate alignment with the grooves in the forming rolls. For this reason, I provide guides adapted to engage the ribs, thus making it possible to maintain alignment irrespective of the gauge of the material. In the drawings, the guides'consist of a block ll of some suitable material such as wood, and rolls I2 provided with a plurality of grooves [3 which are of the exact shape of the ribs as produced in the immediately preceding roll pass. In the form illustrated, the three rollers I! are mounted in a housing ll pivotally connected to the plunger l5 of an air cylinder IS. The guides, with their actuating mechanism, are mounted on a carriage l1 provided with rollers l8 adapted to travel and be guided by grooves I! in the frame members 20. The carriage H is adapted to be moved toward or away from the rollers 2| by the air cylinder 22 and the plunger 23.

The base frame 24 is rigidly fixed to the roll housings supporting the working rolls 2| in any convenient manner, to place the guides in substantial alignment with the grooves in the .working rolls. Accurate alignment of the grooves in the guiding rolls l3 and the working rollers 21 I have found that it is impractical is obtained by moving the frame 20 with respect After the grooves in the guide rollers l3 are placed in alignment with the grooves in the working rolls 2|, the material I0 is placed in the 1 guides, the rollers having been raised by the airscylinder [6 which is then actuated to bring a the rollers down on to the material and apply pressure thereon. While placing the material in the guides, the carriage I! has been retracted from the rolls 2|; but upon placing the material in the guides, the plunger 23 is actuated to run the carriage forward to a point where the material is engaged by the working rolls, the action of which serves to pull the material through the guides.

In the rolling of some materials, it may be necessary to have a slab or plate thickness equal to, or greater than, the total web, rib, and heel height of the first pass, but I have found that the required number of passes may be reduced in the case of many materials by utilizing a slab or plate thickness considerablyJessthan this overall dimension.

This is particularly true in the rolling of certain aluminum base alloys. Fig. 7 illustrates this feature of my invention. The dotted outline 6 indicates the initial thickness of the fiat slab prior to entry into the first roll pass, in which the rib 4, the heel 5, and the web portion 3 are given their forms. In the specific example being I described, the thickness of the slab prior to its entry into the first forming pass was- .610". After the first pass, the total height over the longitudinally-extending projections forming the rib 4 and the heel 5 was .780". To effect this increase in height over the height of the initial flat slab, it is essential that the material have sufilcient ductility at the rolling temperature employed to permit of lateral flow of the metal from the web portion, which is being reduced in thickness, into the rib and heel. If re-heating is not resorted to between successive roll passes, it is apparent that there will be a temperature drop in the material between 'each pass, with a consequent decrease in ductility. It is therefore necessary to provide suflicient material in the rib and heel during the first roll pass to permit of the proportional elongation of the rib with the web. In the subsequent roll passes, there can be no substantial lateral metal flow, and the above described process. By following the meth- 0d of the invention, any lateral flow of the material, after entering the roll pass, is virtually eliminated, therefore the center distance between the ribs in the successive passes need only be varied to compensate for the thermal contraction incident to the temperature drop of the material between the passes.

While but one specific modification of the invention hasbeen illustrated, it will be understood that I do not wish it limited thereto since various modifications and changes will readily suggest themselves to those skilled in the art, and many such modifications and changes may be made without departing from the scope of my invention as defined in the appended claims.

I claim:

1. The method of rolling sheet metal products provided with a plurality of integrally-formed ribs, which comprises passing substantially fiat material through a series of pairs of forming rolls adapted to form oppositely-disposed, longitudinally-extending projections on both sides of said material having a height such that their extremities are spaced apart a distance greater than the initial thickness of said fiat material, and in successive roll passes substantially reducing the height of the projections on the one side of the material until completely effaced while simultaneously reducing the thickness of the web between the ribs.

2. The method of rolling sheet metal products provided with a plurality of integrally-formed ribs, which comprises passing substantially fiat material through pairs of grooved rolls adapted to form oppositely-disposed, longitudinally-extending projections on both sides of said material having a height) such that their extremities are spaced apart a distance greater than the initial thickness of said flat material, reducing the height of the projections on one side of the material by passing the material through successive pairs of grooved rolls having the roll engaging the side of the material from which the projections are to be effaced provided with a groove width greater and a groove depth less than the other roll of the pair, subsequently passing the material through a pair of rolls, one of which is grooved and the other fiat, to completely efface the projections on the one side of the material, and having all of said passes through said rolls adapted to reduce the thickness of the web between the ribs.

3. The method of rolling sheet metal products provided with a plurality of integrally-formed ribs, which comprises passing substantially flat material through a series of pairs of forming rolls adapted to form oppositely-disposed, longitudinally-extending projections on both sides of said material and in successive roll passes substantially reducing the height of the projections on the one side of the material until completely eifaced while simultaneously reducing the thickness of the web between the ribs.

4. The method of rolling sheet metal products provided with a plurality of integrally-formed ribs, which comprises passing substantially fiat material through pairs of grooved rolls adapted to form oppositely-disposed, longitudinally-extending projections on both sides of said material, reducing the height of the projections on one side of the material by passing the material,

7 through successive pairs of grooved rolls having vided with a groove width greater and a groove depth less than the other roll of the pair, subsequently passing the material through a pair of rolls, one of which is grooved and the other cessive roll passes by means of guides adapted to cooperate with said projections, and in said successive roll passes substantially reducing the height of the projections on the one side of the material until completely effaced while simultaneously reducing the thickness of the web between the ribs.

6. The method ofrolling sheet metal products provided with a plurality of integrally-formed ribs, which comprises passing substantially fiat material through pairs of grooved rolls adapted to form oppositely-disposed, longitudinally-extending'projections on both sides of said material, positioning said material for successive roll passes by means of guides adapted to cooperate with said projections, and in said successive roll passes substantially reducing the height of the projections on one side of the material by passing the material through successive pairs of grooved rolls having the one roll engaging the side of the material from which the projections are to be effaced provided with a groove width greater and a groove depth less than the other roll of the pair, subsequently passing the material through a pair of rolls, one of which is grooved and the other fiat, to completely efiace the projections on the one side of the material, and having all of said passes through said rolls adapted to reduce the thickness of the web between the ribs.

'7. The method of rolling sheet metal products provided with a plurality of integrally formed ribs, which comprises passing substantially flat material at hot rolling temperature through a pair of forming rolls adapted to form oppositelydisposed, longitudinally-extending projections on both sides of said material having a height such that their opposite extremities are spaced apart a distance greater than the initial thickness of said flat material and an area in section having the same ratio to the rib area in the final product as the thickness of the material between said ribs bears to the said thickness of the material in the final product, and in subsequent roll passes reducing the combined areaof said projections proportionally with the reduction in thickness of the material between the ribs and simultaneously displacing the material in the projections on one side of the material into the projections on the opposite side.

HENRY L. HARPER.