US1178863A - Method for producing bands of aluminum. - Google Patents

Description

UNITED STATES PATENT OFFICE;

ERWIN RICHARD LAUBER AND ROBERT VICTOR I Q'EHER, OF EMMIS'HOFEN, I

SWITZERLAND.

METHOD FOR PRODUCING BANDS 01E ALUMTNUM.

1,178,863. No IJrawing.

To all whom it may concern:

Be it known that we, ERWIN RICHARD LAUBER, a subject of the Emperor of Germany, and ROBERT VIoToRNnHER, a cltizen of Switzerland, both residing at Emmishofen, Switzerland, haveinvented certain new and useful Improvements in .Methods for Producing. Bands of Aluminum; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

Methods have been proposed by which small sheets or foils of aluminum of 0.0003 inch in thickness can be produced, but strips or hands of aluminum could only be rolled at a minimum thickness of 0.0008 inch, and only a yard or two in length. Bands of a less thickness heretofore have become plaited or torn during the rolling process so that.

they could not be rolled to lengthsdesired by the trade.

According to our invention, aluminum, after being annealed by I 320 C. and then allowed to cool, is drawn by rolls at a high tensile strain and under a comparativel small pressure. ingly bands 0 aluminum of a thickness less than 0.0008 inch, as for-instance 0.0003 inch, can be produced, which becomes neither plaited nor torn, and may be produced a mile, more or less inlen th."

When producing only one ban according to our method, a thick band or strip of aluminum, after having been heated to 270 to 320 C. to anneal the same is wound onto a roll, and the band passed from the latter while being braked between two rollsdriven in opposite directions and at a small pressure, the band becoming elongated thereby. The strip is consequently subjected simultaneously toa rolling and drawing action.

The material can best be elongated when annealed at the above mentioned tempera ture, as it then possesses the highest available tensile strength. As the material retains this strength when becoming cold again, but loses it by mechanical treatment, a repeated annealing of the material at the above mentioned temperature becomes necessary from time to time. 1 This annealing Specification of Letters Patent.

heating to 270 to- Accord- Patented Apr. 11, 1916.

Application filed September 21, 1911. Serial No. 650,505.

may be performed at suitable intervals during the treatment of the material. As a consequence the aluminum band can be sub- Jected to so high a tensile strain that it is not only elongated, but is also brought in v a smooth condition to the rolls.

Oil is suitably introduced between the metal and rolls during the drawing operation, and as the surfaces "of the rolls become smoothed thereby the polishing of the rolls is rendered unnecessary as in processes heretofore practised. Any good lubricating oil 1s used, such, for example, as motor oil, automobile oil and the like; For rendering the material smooth and ductile, the strip or band when rolled to less than 0.0008 of an mob in thickness is annealed in the presence of air. i

Hitherto separate thin strips or bands of i only limited length could be produced simultaneously on account ofthe lubricant employed such as a layer of oil, petroleum,

soapy water or the like, which was intro duced between the layers of metal to prevent them from becoming stuck together. Exper ments have proven that these fluids can be applied as separating layers for alumlnum foil of only about 0.0008 inch thickness or more. Strips or bands of less thickness become perforated like a sieve, by the employment of these lubricants, and by reason of thegranulation of the metal due to the elongation beforeit enters the rolls. The separating fluid by its hydrostatic pressure then breaks through the weak parts of the band. A layer of lubricant, as oil, which adheres to the material from a preceding elongation exerts the same unfavorable act1on. Experiments have proven that the perforation by lubricant which adheres to the material from the preceding rolling beginls with a thickness of the foil of 0.0006 inc By our method bands consisting of several layers of aluminum may'be produced band at the last period of rolling but before being folded into two bands and wound up,

is rolled with a mixture consisting of a-' small amount of lubricant, as oil and a volatile solvent, as benzin, petroleum, turpentine or similar materials. So small an amount of fluid is applied that only a very thin layer of this limpid liquid and slightly adhering mixture covers the foil, when leaving the rolls. Thus a sticking of the two layers to'each other is prevented, and, on the other hand the layer of lubricant is too thin to perforate the foil. The same result can be obtained by introducing between the strips or bands, vapor, for instance steam, vapor of oil, alcohol, ether or benzm, so that the bands, when passing the rolls are separated from each other. by a very thin and well distributed layer. Thus for 1nstance, the aluminum band before being rolled two-fold is freed from the oil adhering to it from the preceding rolling. This may be done by evaporating the oil, or by washing with a solvent, as benzin. Afterward, a tube provided with a large number of fine openings is placed between the bands at the side where they enter the rolls. The tube which may be electrically heated is supplied with the fluid to be evaporated, alcohol or ether for instance, and a fine layer of vapor, which exerts no hydrostatic pressure, is formed thereby between the alumlnum bands entering the rolls.

A verythin uniformly distributed, separating layermay also be obtained in the following manner: Bands still of so great a thickness, (0,0008 inch or more) thatthey are not perforated by the heavier lubricant introduced between them, are freed from their coating of lubricant or oiland wound up. An easily evaporating fluid 1s introduced between the layers before or as they enter the rolls. The bands after passing the rolls are wound up tight and the woundup bands, with the separating layers between the single bands, are heated so that the surplus of separating fluid is evaporated'and the remaining part ofsaid fluid in the form of vapor is equally distributed between the bands where it is condensed to a very fine separating layer. The bands separated in this manner may be rolled and drawn to 0.00025 inch, as has been proven by experiments. These bands neither stick to each other nor become perforated. By rollingseveral superposed bands at the same time the product is increased, as compared with rolling single bands, moreover the product consisting of several bands stands the Working process better than single bands.

I We believe that we are the first to produce aluminum foil of less than two onehundredths (.02) of a millimeter in thickness (0.0008 inch), and in fact we have exceeded all expectations and have produced single strips of aluminum foil six and eight one-thousandths of a millimeter (0.0002

in the form of a band while under tensile strain and under a small pressure, the band becoming elongated thereby to a thickness less than 0.0008 inch, substantially as described.

2; The method of producing aluminum foil in the form of bands, which comprises annealing sheet aluminum at a temperature of from 270 to 320 C., rolling the aluminum in form of a band under a high tensile strain and under small pressure and lubricating the surfaces of the aluminum.

3. The method of producing aluminum foil in form of bands, which comprises lubricating the surfaces of several superposed aluminum foils by very fine and well distributed layers of lubricating fluid to prevent the sticking of the foils to each other, repeatedly elongating the foils while under high tensile strain by a slight rolling pressure to a thickness of less than 0.0008 inch, and annealing the aluminum at intervals of the rolling operation, substantially as described.

i. The method of producing aluminum foils in band form, which comprises-simultaneously elongating several superposed aluminum foils while said foils are under high tensile strain but under small pressure to a thickness of less than 0.0008 inch, lubricating the surfaces of the foils by the condensable vapor of a suitable lubricant before elongation, and annealing the aluminum at intervals of elongating operations, substantially as set forth.

5. The method of producing aluminum foils in form of bands, which comprises lubricating the surfaces of superposed strips of aluminum, removing the excess of lubricant by vaporization, repeatedly subjecting the superposed strips to a rolling operation at a slight pressure while the strips are under tension to a thickness less than 0.0008 inch,.a-nd annealing the bands at intervals during the rolling operation, substantially as described.

6. The method of producing aluminum foils in band form, which comprises annealing the aluminum at a temperature of 270 to 320 C., rolling superposed bands of aluminum under a high tensile strain and un' der a small pressure while lubricating the surfaces of the aluminum, freeing the bands from excess of lubricant, coating the surfaces of the aluminum with a very thin,

well distributed layer of lubricant to prevent the foils from sticking together, and repeatedly elongating the foils under high tensile strain and slight pressure to a thickness below 0.0008 inch, substantially as described.

7. The method of producing aluminum foil, which comprises annealing the aluminum at a temperature of 270 to 320 C., rolling the aluminum in superposed bands under high tensile strain and slight pressure while lubricating the aluminum surfaces, freeing the bands from lubricant and then lubricating the surfaces of the bands at subsequent rolling operations with very fine well distributed layers of a fluid to prevent the bands from sticking together, and repeatedly elongating the bands under high tensile strain and slight pressure to a thickness less than 0.0008 inch, substantially as described.

8. The method of producing aluminum foil, which comprises annealing the aluminum at a temperature of 270 to 320 0., rolling the aluminum into bands while lubricating its surfaces and while under high tensile strain and slight pressure, removing the lubricant from the rolled bands, superposing and rolling the resulting bands while under tensile strain and pressure and during such rolling providing the surfaces of the bands with a thin lubricant well distributed to prevent the sticking together of the bands, and repeating the rolling under strain and pressure until the thickness of the bands is less than 0.0008 inch, substantially as described.

9. The method of making very thin and long aluminum strips, which comprises repeatedly rolling the annealed aluminum while under tensile strain and slight pressure, then rolling several annealed layers of the resulting foil while under tension and slight pressure, lubricating the surfaces of the layers with a thin lubricant, and continuing the rolling operations underhigh tension and slight pressure until the strips are less than 0.0008 inch in thickness, and periodically annealing the metal between some of the rolling operations.

10. The method of making very thin strips of aluminum foil, which comprises repeatedly rolling a thick strip of annealed aluminum while under tension until thin, then lubricating the surfaces with a thin lubricant and continuing the rolling operations under tension and pressure, and annealing at intervals of the rolling operations.

11. The method of making very thin and long aluminum foil, which comprises repeatedly rolling thin lubricated strips While under tensile strain and slight pressure, and annealing the strips at intervals of the rolling operations.

In testimony that we claim the foregoing as our invention, we have signed our names in presence of two subscribing witnesses.

ERWIN RICHARD LAUBER. ROBERT VICTOR NEHER.

Witnesses ERNST FISCHER, CARL CUBLpR.