US1915391A

US1915391A - Coating mixture

Info

Publication number: US1915391A
Application number: US645950A
Authority: US
Inventors: Merle J Stoops
Original assignee: Individual
Current assignee: Individual
Priority date: 1932-12-06
Filing date: 1932-12-06
Publication date: 1933-06-27
Anticipated expiration: 1950-06-27

Description

Patented June 27, 1933 UNITED STATES PATENT OFFICE I Drawing. hpplieation filed December This invention relates to the coating of metallic sheets or breakdowns for the purpose of preventing adhesion of superposed sheets during the process of pack rolling, by

which the sheets are'elongated until they have the desired. thickness. The invention is also in'the nature of an improvement upon the compositions and processes disclosed in my rior, copending application, Serial Num r 576,224, filed November 19, 1931.

Heretofore, various attempts have been made to provide a satisfactory coating for the abuttingfaces of the sheets of a pack to be rolled for the purpose of preventing adhesion of the sheets when heated and rolled. Such abutting faces, heretofore, have been coated with various compounds which, to some extent, resisted adhesion of the sheets to one another, but difliculty was experienced in 29 preventing such adhesion of the sheets and,

' at the same time, obtaining sheets of desired quality after rolling such as sheets which are clean, stainless, white in appearance, and have a close grained and high, glossy surface or finish.

An object of this invention is to provide an improved coating mixture for, and method of, treating the metal sheets of packs for pack rolling, by which adhesion of the sheets to one another during rolling will be eflectively prevented; with which sheets may be fobtained that, after rolling, will be superior ,in'appearance and quality to those heretofore obtained; which will give dependable and uniform results; and which will be relatively simple and inexpensive.

I have now discovered that superior results in pack rolling may be obtained by the use 40 of my improved coating composition which is applied to the sheets of the pack before the sheets are heated and rolled. In accordance with my discovery, I prepare the coating mixture of finely divided carbon in a plu- A 5 rality of different, chemically uncombined forms that are mixed into and carried by a liquid suspending medium. When this mixture is applied to the faces of the sheets, it forms an adherent coating that protects the 6 faces of the sheets during the heating and manta :I. swore, or BLASDELL, NEW YORK I comma mxrunn e, 1922. Serial no. 645,950.

' rolling operations,'and produces an improved finish on the faces of the sheets. Preferably, one of these chemically, uncombined forms of carbon to be used is graphite, and the amorphous and crystalline forms thereof are the most satisfactory. While the flaky graphite may be used, I have found it less satisfactory than the amorphous. or crystalline forms of the graphite. The other forms of the chemically, uncombined carbon in finely divided condition ma be finely divided charcoal and lampblac or other soot. The liquid suspension medium is preferably an aqueous solution of a sugar, such as molasses or glucose, and I have found that glucose gives better results than the molasses or other sugars in that there is less discoloration of the sheets with the use of the glucose. The sugar or glucose. acts as a mixing agent for the lampblack or other soot, since it is diflicult to cause lampblack to mix with water alone. This sugar solution is also preferably fermented to some extent before the coating is applied to the sheets, so as to provide some alcohol in the suspending medium. While an aqueous, alcohol solutionmay be used, I 3 have found that commercial alcohol for this purpose is expensive and that equally satisfactory results may be obtained by providing 90 the solution of the glucose or molasses and fermenting it either before or after admixture with the various forms of carbon.

As a specific example of a coatin mixture which embodies my invention or iscovery, the following sample mixture is given:

Lampblack 10 lbs. Graphite 10 Charcoal a- 20 Glucose; 2 Water 400 gal.

These materials are thoroughly mixed together and allowed to ferment to some extent, the fermentation being accelerated, if desired, by the addition of a ferment, such as yeast, to the mixture. If desired, the glucose and water may be added to the lampblack or other soot and thoroughly mixed therewith, and after the fermentation is thecharcoal, if charcoal is used. While the v ingredients of this composition ma mlxed in any desired order, or the soli s all started the graphite may be added and also added to the liquid at the same time and stirred therein, I have found that somewhat better results are obtained if the graphite is added after the fermentation has started. The mixture may be used for coatin purposes before the fermentation is complete or after the fermentation has stopped.

' I'have found that for the most satisfactory results, the lam black or other soot and the graphite shoul be used in approximately equal proportions, but the proportion of the charcoal may be varied through a wider range andmay be used to some extent to replace the lampblack or other soot.

' ampblack or other soot may be entirely re- The placed by the finely divided charcoal, if desired, but I have found that with little or no lampblaok and a major amount of charcoal it is not possible to obtain as glossy a finish as when more of the lampblack is used. If desired,- little or no charcoal may be used in "which case a larger proportion of the soot or 1am black may advantageously be used,

but sue a mixture is more expensive than when some charcoal is used.

After the mixture of different forms of finely divided, chemically uncombined carbon with the suspension medium has been made, the sheets to be rolled are coated with this liquid mixtureand allowed to dry. The

sheets are then placed in packs, heated to,

the rollin temperature and then rolled, during which the sheets are enlarged in area and reduced in thickness. The coating may be applied to the sheets in any suitable manner, such as by dipping the sheets into the liquid mixtureor by spraying the mixture 11- on the sheets. The coating mixture may,

i desired, be heated so that the sheets coated therewith will dry rapidly, and the coatin" retained upon the sheets will remain fixed thereon while the sheets are being handled and matched up. The exposed faces of the sheets of the packs, such as the tops, and but tom faces of the pack, mayalso be coated with the mixture in order to protect them under the rolling pressure placed thereon during the rolling operation.

It is important that the various forms of carbon used be .in very' finel divided condition in order that they will be more easily and uniformly retained in suspension in the mixture and, consequently, more uniformly spaced. upon the sheets. The finer the particles, the fewer the imperfections and indentations which will be formed on the surface of therolled sheets and, therefore the hi her the uality of the sheets. Whi e rap ite and c arcoal in a' water mixture could be used as a coating mixture and would result in" sheets having some of the advantages of my discovery, a brighter and better sheet is obtained when the coating mixture includes lampblack or other soot and the fine particles are carried in suspension in the fermented solution.

In the heating operation, just prior to the rolling, the charcoal is the first to burnout and, when burned, leaves a slight ash which aids in keeping the iron sheets from sticking to one another. The charcoal mixture .forming the coating also aids in keeping the lampblack or other soot and the graphite particles separated or spread evenly, and thus reduces the cost-of the mixture since the powdered charcoal is less expensive than the soot or lamp black andthe gra hite. The

graphite is the best lubricant ween the sheets and will withstand hightr furnace temperatures before burning. out, than will the lampblack or charcoal, so that the sheets so coated may be heated to a much higher temperature in the furnace before'rolling than when lampblack and/or charcoal alone is used. Consequently, the sheets at the higher temperatures ma be rolled more easily and perfectly and with fewer defects because less force is required to elongate the material of the sheets at the higher temperatures.

Among the advantages resultin from the rocesses menuse of the improved mixture an according to this invention, may

tioned the following. The improved coating resists the formation of scale and oxides on the metal sheets during the heating, of the sheets preparatory to rolling, prevents or lessens scratching of the sheets, and also the formation of the scale on the sheets in the anflashes and discoloration, will not sweat while placed in piles in the finishing department, will not rust or undergo other changes due to atmospheric conditions during storage or shipment, even. though the sheets are cleaned of the coating before shipment, because dur-,

ing the rollingof sheets coated in this man-. ner, the surfaces of the sheets have been closed so thorou hly and such a highly glossy surface prodTzced, that it is impossible for water or moisture to get into the pores of the sheets and set u Sheets coated: before rolling, in accordance with this invention, have such a, smooth,

a rusting or scaling action.

glossy, and closed grain surface that the cost of subsequent cold rolling to provide such a surface is largely saved. The lampblack or other soot and the charcoal maybe considered as a controlling agent for the graphite, to prevent slipping of the graphite, or

displacement thereof. Since the sheets coated in accordance with this invention may be heated to a higher temperature for the rolling operation, the sheetswill not be hardened by the rolling to the extent that would occur under excessive cold rolling, and consequently have better drawing properties than sheets heretofore possible.

It will be obvious that various chan es in the proportions of parts of the ingre lents, in the order of the steps and in the other'details, which have been herein set forth in order to ex lain the nature of the invention, may be ma e by those skilled in the art within the principle and sco e of the invention, as

- expressed in'the appen ed claims.

-I claim:

1'. A mixture for use in preventing adhesion between metal sheets during pack rolling or the like, containing finely divided carbon in a plurality of different, chemically uncombined forms, one of .which is graphite, and a fermented sugar solution.

2. A mixture for use in preventing adhesion between metal sheets durin pack rolling or the like, containing finely ivided carbon in a plurality of different, chemically uncombined forms, one of which is graphite,

and a fermented glucose solution.

3. A mixturefor use in preventing adhesion between metal sheets during pack rolling or the like, containing. finely divided graphite, finely divided charcoal, soot, and a fermented, liquid suspension medium.

4. A mixture for use in preventing adhesion between metal sheets during pack rolling, or the like, containing finely divided graphite, finely divided charcoal, soot, and a fermented liquid suspension medium, mixed in the proportions approximately of 10 pounds each of graphite and soot, 10 to 30 pounds of charcoal, and 400 gallons of liquid.

5. A mixture for use in preventing adhesion between metal sheets during pack rolling or the like, containing finely divided carbon in a plurality of different, chemicall uncombined forms, and a'fermented, liqui suspending medium. I

' MERLE J. STOOPS.