US1683003A - Rolling sheet metal - Google Patents

Description

Sept. 4, 1928. 1,683,003

J. B. TYTUS RQLLI NG SHEET METAL Filed April 30, 1926 [)JZENTOR.

Patented Sept. 4,1928.

UNITED ST TES.

PATENT OFFICE JOHN B. Tyros/or mronnnrown, OHIO, nssrenon r THE AMERICAN ROLLING MILL coin-ANY, or MIDDLETOWN, onro, A CORPORATION or onto.

ROLLING SHEET METAL.

Application filed: April 30,

My invention relates to the method of rolling sheet metal in packs in Order to get fine reductioin'by successive roll reduction in a. series of stands of .rolls, each acting on the pack but once. k

l have hitherto discovered that in rolling thin wide metal pieces such as the customary sizes ct steel and iron sheets in the industry I at the present time, that the difficulty in attempting a continuous process is that the active pass, in each stand otrolls must beparticularly controlled in order to successfully keep the piece fiat, and feed it accurately through the stand. v

lit has been assumed in the past that the desirable way to roll sheet metal in successive stands ot' rolls'was to keep each pass as flat or truly rectangular in contour as possible; whereas my process calls for the formation of a contour of pieces that isthicker along the median line than at the edges, and in each stand of rolls attenuating the median thickness more than the edges of the piece are attenuated.

In other words, by my process the active pass, or shape of the space between the rolls when the metal being rolled is embraced nating this factor it is easier to maintain an active pass of deslred contour.

between them, must be less convex as compared to a horizontal plane, in each successive stand, with the final convexity such as will not diverge sufficiently frbm com mercial allowance in the judging of fiat metal sheets.

I have also discovered that where the j proper convexities of active pass are maintained, it is possible to-roll hot metal packs,

between rolls which are kept cold. By cold in the hot metal rolling mill is meant a temperature that will maintain a film during rolling on the surface of the rolls. Rolls are kept cold in' hot rolling by spraying j with water.

There is a decided advantage in keeping a the rolls ,cold, in my process, because this eliminates one oi. the variable factors going 1 to make up the active pass. rolls are unevenly heated or vary in heat 1 at one time from another, their diameters or shape will change due to the hotter metal Thus if the expanding more than the cooler. By elimi- I have also discovered-that it is necessary, packs by a continuous process 192a Serial 1%. 105,845.

pieces making up the pack from sticking cold, and packs which are rollable because Finally in the use of rolls which are kept I hot, the degree of heat in the packs is factor of the active pass in each stand of rolls, so that it is my practice to provide temperanture controlling means for the metal, packs between stands of rolls. I a

It is the Object of my invention'to provide a process of pack rolling, in which one or two small diameterrolls are applied to the piece, inswhich'these rolls are kept cold, in which. the temperature control of the packs is provided for, and in which the progressive convexity reduction from pass to pass is provided for by theinature er the ,rolls,'and prearranged settings of the pres- I Y sure applying screws thereon for packs of a prearranged contour to begin with.

' The advantage resulting from the use of small diameter rolls in connection with the rolling process arises from a series of fac tors, some heretofore recognized, and some not. I

If a piece of relatively thin metal, such as a pack for example, is passed between standard sized rolls, the area of the pack under compression between the rolls at any given instant is much greater than if one or both of the rolls were of small diameter. Keeping in mind that in rolling the power is applied, as torque and not as pressure, and

that the adjustment of the screw holds the journals of the rolls against separation, rather than forcing them about the piece, still the result of the action in the mill is to spring the rolls, apply compressive strain togthe pack, and'spring the housings of the mill aswell. By cutting down the size of one or both the rolls and backing them with large diameter rolls for stiffness, I can get the same amount'ot reduction of a pack with (1) less frictionat the necks and hence expenditure of power and creation of heat which distorts the shape of the rolls, (2) less ,spring of the rolls, because less compressive strain is applied, resulting 1n less pressure on the pack as well, thus avoiding 111i the danger of sticking the parts thereof together, (3) less difficulty due 'toelasticity of the housings in which the rolls are supported, thus making the screw settings more positive in their results. I v I It is evident that with the added availability of the several features above outlined, I am enabled to produce very thin gauge metal sheets in packs with a minimum of labor, economy ofv replacement in case of roll breakage in the small rolls, and

with simplicity of control of active pass.

I have illustrated in the drawing atypical installation of sheet mill for accomplishing my process, and will proceed to describe'my process in connection therewith, and point out the novelty inherent therein/in the claims that follow.

' ment of my invention.

. ing the spacing of the rolls from eachother.'

Figure 2 is a sectional diagram of a four high stand.

housings 1, which are preferably of a rigid type, with screws controlled at 2 for adjust- In each stand are three rolls, a large bottom 3d roll 3, a central idle roll 4 of small diameter,

and a large upper roll 5, the upper r011 being the one to which the screw is applied. 1 I have indicated shower pipes 6, by means of which water canbe sprayed on the rolls, thus keeping thereon a film of water, the rolls being then termed cold in the rolling mill industry.

I have shown tables 7 between the stands of rolls by means of which the packs are fed and I have shown furnaces 8, throu h which the packs are fed between stands. T e furnaces have been broken away, except for the one to the right, and the feed table be- 0nd the furnace to the; right has been .pack from each other, if they have points of partial adherence. A full adherence without spots of looseness is-perhaps practical, and a complete freedom of the sheets from the others 1n the pack is preferable, but

a partial adherence and a partial looseness is absolutely to be prevented, and hence the space mustbe given, and time factor be and stripping should this be required.

The small inner roll maybe held freely in the housings so as to be removable, and in controlling roll contours, the small inner roll need not be other than cylindrical, since 1t will take the shape of the larger upper has been termed, contour.

have indicated a series of roll stand .duce thepacks between rolls which are kep In directing the operation of the typica roll against which it bears. The breakage of the small diameter roll will thus be easy to repair by quick insertion of a new one. Instead of having one small diameter roll there may be two, as indicated in Figure 2 where there are large rolls 9 and 10 and smaller inner idler rolls l1 and 12. e

In the process a pack is provided which has a known crosssectional shape, which It is heated to the proper degree forrolling, and preferably rolled so that the pieces making u the pack will not adhere to each other. ach stand of rolls is kept cold with a film of water, and preferably each furnace will be kept at a temperature sufli'cient to maintain the pack at somewhat higher temperature than-is normally practiced rolling by repassing through a single stand, as inthe Welsh process.

In preparing the several rolls for the stands that the piece is to pass through, the grinding or turning will be such as to give under normal operation an active pass in each stand of progressive difference, and other factors entering into the active pass will be controlled b the operator depending upon the contour o the pack with which he is provided.

Thus the grinding of the rolls is practiced so as to give a slight crown to all-of the large rolls, and more of a crown to the larger rolls in the first stand. Thisis because the pack is thicker in the first stand, and granted a uniform extension in each stand, the tendency of the pack to spring the rolls will beless, where the pack is thinner.

The screw on the rolls is a factor in the roll contour during the moment that the pack is between them, as is the temperature ofthe pack, and its'thickness. Where the rolls are at a uniform temperature, as when kept cold the'factor of differential expansion of the rolls, is largely eliminated from my present process.

The necessities of the use of additional heat to keep the packs up to temperature fp rolling and preferably slightly higher than in usual Welsh process rolling, arise part1 from the necessity of keeping the contou of active pass correct, and the several passe in a series uniform in temperature in eac pass, and partlybecause by my process I re cannot be'fast enough to avoid re-heating.

mill shown, once installed, the rollers wil be instructed that in each stand they shoul take down the center-of the pack more tha the edges, and that they should work on screw settings and temperature control o the packs,so that when starting with a run of packs of a given degree of convexity, the first stand should be controlled and the successive stands set with regard to the first stand so that each active pass will have less convexity of contour. In each case also the piece should be kept at a prearranged temperature for each stand. Thus each successive stand after the first must be controlled so that the spring of the rolls about the piece will be proper'to reduce the median area of the piece more than the edges, the-general rule being to reduce the total thickness at the middle proportionately as the length of the piece over-all is increased by the pass. Due to the lower power expenditure secured by my method in each pass it is possible to more accurately control the contour of active pass than in a case where the control of contour might afie'ct the amount of extension of the piece di'sadvantageously. Also a thinner product will result from a given number of passes.

The convexlties spoken of, are naturally slight and not determinable by the eye, but ina thin piece it is necessary to control the contours by prearranged plan, so that the v active pass of each stand is correct for taking the product of the preceding one. All of the furnaces need not be used, all of the time, as control of temperature may require blanking one ,or more of them on particular runs.

As has been stated, the fallac of former endeavors to roll packs by a continuous process has arisen from the fact that the experimenters disregarded the spring of the rolls, or else tried to control it to give the unnatural effect of a completely parallel set of roll faces presented to the piece lying therebetwcen at each pass.

Not only does the failure to observe the rule of progressive lessening of convexity curve incross section of the piece, result in failure to get an even and fiat product, but it results in a piece WhiClLWlll not exhibit a natural tendency to feed through the center of the roll passes.

This application is directed to a final reiinement of my continuous rolling process for packs and thin metal generally wherein I obtain a high degree of reduction by the added device of using a single-or double small diameter rolls, backed by large diam- .eter ones, since I employ the added features of keeping the elements thereof from partial adherence, and preserving a progressively less convex active pass from stand to stand.

I am thus able to reduce to a minimum flat and satisfactory sheet, I can make a thinner sheet than ever before, and have eliminated very fully the chances of inadequacy of the apparatus used to produce a product of uniform length regardless of the practical range of convex contours to be met with in the heated packs with which my process starts.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. A process of rolling hot packs for the production of sheets which consists in assing the packs through successive stan s of rolls in a series, and in said stands engaging the packs by small diameter rolls backed by rolls of larger diameter, said rolls being maintained cold, and controlling the temperature of the packs between selected stands, and preserving an active pass in each stand which has less of a convex curve, than the convexity of the pack prior, to its passag therethrough.

2. A process of rolling hot packs for the production of sheets which consists in assing the packs through successive stands of rolls in a series, and in said stands engaging the packs by small diameter rolls backed by rolls of larger diameter, said rolls being maintained cold, and controlling the temperature of the packs between stands, and preserving an active pass in each stand which has less of a convex curve, than the convexity of the pack prior to its passage therethrough, said packs being open to manipulation between stands for the purpose of preserving the pieces making u the pack from partial adherence to each ot er.

3. A rocess of rolling hot packs for the product on of sheets which consists in passing the packs through successive stands of rolls in a series, and in said stands engaging an active pass in each stand which has less of a'convex curve than the convexity of the pack prior 'to its passage therethrough, said preservation of active pass being maintained by predetermining the contour of a run of packs, maintaining the heating requirements so as to give each stand of rolls a pack of the same temperature, and to provide a metal of'proper degree of softness and arranging and maintaining the pressure applied to the rolls in each stand with relation to each other stand and w1th relation to the packs beingrun. I

JOHN B. TYTUS.

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