US1316018A

US1316018A - A cokpoba

Info

Publication number: US1316018A
Authority: US
Publication date: 1919-09-16
Anticipated expiration: 1936-09-16

Description

f PATN OND DEWEY 0.00m, 0F TE HAUTE,

INDTANA, ASSTGNOE, TO COLUMEIAN ENAMEJLTNG @t STAMPTNG COMPANY, F TERRE HAUTE, INDIANA, A COEJPU- TIUN OE TANA.

n werner-n or nn' specification of Letters Patent.

ELEiD W.

Application med April d, 1919. Serial No. Steff.

scription of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

'This invention relates to the manufacture of enameled ware and more particularly to the production of enameledl ware from sheet steel, or similar metal, and to the treatment of the sheet steel as a preliminary to the Alb enameling operation.

lin the production of enameled ware, the steel is customarily pickled in acid solutions to clean the surface and the enameling is then carried out as expeditiously as possible to guard against the oxidation of the clean surface; and it has been an axiom of the enameling industry that the presence of oXid on the surface of the steel was a condition to be strenuously guarded against.

rlFhe usual procedure followed in preparing the steel for enameling is briefly as follows: rThe steel-is received nin the form of rolled sheets and is pressed or drawn' into the form of culinary or other utensils. To facilitate this drawin operation, and to permit the steel to pull reely through thedies, an emulsion of mineral oil is applied to the sheet.

After the utensil has been shaped the customary operation is the removal of the oil by scaling. The practice in this operation is to dip the ware in an acidbath and while wet with the acid to heat it to redness for several minutes. By this treatment the oil is burned 0E, and the coating of iron oxid which results is in a condition to 'be removed by the action of a pickling solution. Ur the oil may be removed by scrubbing the utensil with a soap solution or soap powder or similarldetergent. lln either case it is necessary that the steely be subsequently cleaned by subjecting it to a pickling treatment, that is by immersing it for sometime in an acid solution to remove the oXid. The acid solution is usually a solution of mineral acids, such as sulfuric orl hydrochloric acids, or an acidr enameling operation,

.layer of oXid takes place,

containing solution such as a solution of sodium acid sulfate.

The operations thus commonly employed for the removal of the oil from the steel and for the cleaning of the steel are expensive, and the apparatus therefor occupies considerable space. lf the oil is removed by heating, a furnace is necessary for the carrying out of the heating operation. rlhe operation of scrubbing with a detergent is likewise an expensive operation. Where hot pickling liquids are employed, the provisionof heating means is necessary. The pickling operation consumes considerable time, is of a disagreeable character, and requires considerable apparatus and space therefor, the coat of acids and of steam for heating forms a very considerable element of expense in the operation of an enameling plant.

According to the present invention the preliminary treatment of the oiled surface of the sheet steel for the removal of oil, and the subsequent pickling thereof prior to the are avoided, and the sheet steel with its oiled surface is subjected to a combined heating and oxidizing operation which leaves the surface of the sheet steel in a condition well adapted for the enameling treatment.

The present invention is based upon the discovery that, contrary to what has been commonly believed, freedom from oXid of the steel surface to be enameled is not necessary; that the usual operations of cleaning, pickling and washing can be "avoided, that the oil or grease present on the steel after the drawing operation can be removed, and the steel placed in condition for the enameling operation, b-y a simple regulated heatin of the steel ware to the proper degree; an that the resulting steel ware, which has an oxid coating, is well adapted for use, without further treatment, in the enameling operation. p

As the result of my investi ations, ll have been led to Ibelieve that the ormation of a in the common enameling operation, while the steel with its enamel coatmg is being heated to the required temperature for the fusion of the enamel, and that the formation of such an o lid layer under the enamel is essential to the proper adherence and .smoothness of the while enamel; and I have found that the enamelgram'matic manner, ing operation can be promoted by the formadrawings, in whichtion of a proper oxid coating upon the steel v Figure I shows the furnace conventionally prior to the application 'of the enamelng in side elevation;

composition thereto andthe subsequent i'ir- Fig. 2 is a transverse sectional view; and 70 ing operation. v Fig. 3 is an enlarged view showing a suit- In the practice of the present invention, able form of chain conveyer.

the steel ware with its coating of oil is sub- The lire brick tunnel 1 is suitably supportjected to a short heating operation at such ed b-y supports 2 and heated by seiies of a. temperature that the oil will be quickly burners 3. Supported on the staggered volatilized or burned and the steel will be .Y bricks 4 is a hearth 5 having bearing plates in the accompanying l oxidized to the desired degree. It has been 6 for the links 8 of the chain to which the found that the amount of oxygen taken up cross bars 7 are secured. .The endless chain by the steel, when thus oxidized, 4was about passes yover end rollers or sprockets 9 and 0.0004 gram per square centimeter, or that 10, a suitable worm or other drive (not the amount of iron oxid formed wasalbout shown) being provided for driving the p 0.0014 gram per square centimeter. The sprocket 10. A supporting or guide rail oxid formation should be such that the steel ll is provided for the endless belt on its rehas a pronounced blue color. In general, the turn. Openings for the escape of products vsteel should have as deep a blue color as posof combustion are indicated at l2.

nacel can be similarly increased.

sible, without becoming black. I have ob'- In the operation of the apparatus the tained good results in the practice of the insheet metal ware is supported on the cross vention, by carrying out the heating operabars 7 or on projections therefrom, and is tion in a gas furnace maintained at a temcarried through the furnace and there heatperature of about 700 C. and by subjecting ed in the manner above described. A suiii- 90 the steel ware to the temperature of such a cient length of the endless chain is provided furnace for a period of about thirty seconds. at the discharge end of the furnace so that In this time the' steel being treated does not the ware will be cooled before it is finally reach the temperature of the furnace, and removed. consequently the oxidation is not carried as It will be evident that, far as whenY the steel itself 'becomes red hot. character described, the A di'erent temperature or time of heating, furnace and of different which will produce the desired blue oxid be readily regulated. coating, may be used in place of the particu- The oxidation of the steel should not be lar conditions above mentioned. carried too far and the oxid film produced gas red furnace of the leer type has shouldA not become too thick, otherwise it been found well adapted to the practice of will not be entirely absorbed by the molten the invention. I have thus used to advanenamel during the ,enameling operation. tage a furnace having a lire brick tunnel The function of the layer or Hlm of oXid, as 10 feet long, 30 inches wide and l2 inches I believe, is to provide a medium through 105 high at the center, with the gas burners which the enamel is secured to the steel, so placed below the bottom of the furnace, and that the com-position of the enamel changes with circulation of the gases therefrom progressively from pure enamel to enamel through openings between the bottom and containing increasing quantities of iron sides of the furnace. The burners were so oxid which is united to the underlying iron arranged that all or any portion of the by means of the iron oxid union. It appears length of the furnace could be heated and to be essential for substantially all of the were provided with an automatic constant oxid Y.film to b e absorbed by the molten temperature control. An endless chain was enamel, in order to obtain a proper union run through the furnace over the sprockets of the enamel with the metal. Ground and at each end, so that the ware could be fed in polished cross sections of sheet steel which has been enameled after treatment in the speed of the chain and the length of the manner above described, when examined ina furnace `of the 95 temperature of the parts thereof, can

en pickled before enameling, p e pickling does not, as is sometimes `supposed, yield a surface which is however, be somewhat varied to bring about rougher and promotes a better union of the the desired oxidation, e., to produce a deep enamel with the steel. blue color. By increasing the length of the From the above description it will be seen furnace and correspondingly increasing the that the process of the present invention speed of the chain, the capacity of the furavoids the/necessity for the usual cleaning and pickli'ng treatment, that the burning furnace of the character above referred olf and'removal of grease and other foreign to is illustrated, 1n a conventlonal and diamatter from the steel ware can be effected 130 by the same operation which results in the formation of an oXid coating, and that by the heating of the steel ware to the proper degree an oxid coating is formed to which the enamel coating can be applied directly without. any preliminary pickling operation. rl`he optimum quantity of oxid that has been found desirable can be developed by the regulated heat treatment which is also suflicient to completely volatilize or burn the oil present on the steel, and the steel, after such treatment, can be enameled directly without further preparation, and with the resulting production of an enamel comparable in quality to an enamel whichhas been applied to pickled steel.

The enameling operation itself, to which the oxidized steel is subjected, may be the customary enameling operation to which pickled can be carried out in the usual way, z'. e., by'

applying the enamel to the oxidized surface, drying and firing.

ll claim 1. rllhe method of making enameled ware, which comprises subjecting sheet steel having an oil coating thereon to a regulated heating to remove the oil and form a blue oXid coating thereon, and subjecting the resulting oxidized steel to an enameling operation, whereby preliminary treatment of the oiled surface for the removal vof oil and subsequent pickling thereof prior to the? enameling operation are avoided.

2. rllhe method of producing enameled ware, which comprises subjecting sheet steel having an oil coating thereon to a drawing operation to shape, heating the ware to remove the oil and produce a thin oXid coating thereon, applying the enameling composition to the oxidized surface, and firing the resulting ware, whereby preliminary treatment of the oiled surface for the removal of oil and subsequent ,pickling thereof prior to the enameling operation are avoided.

3. The method of enameling steel ware havingy an oil coating thereon, which comprises subjecting the ware to a temperature of about 700o C. for about 30 seconds to steel isj subjected, and this operationproduce ware of the desired' remove the oil and produce an r oxidized surface, and subjecting the resulting oXidized ware to an enameling operation, whereby preliminary treatment of the oiled surface for the removal of oil and subsequent pickling thereof prior to the enameling operation are avoided.

a. The method of enameling steel ware having an oil coating thereon, which comprises continuously passinq the ware through a furnace, heated to afbout 700 C., at .such a rate that the ware will be subjected to such temtperature for a period of about 30 seconds, and thereby removing the oil and producing a thin oxid coating, and subjecting the resulting ware to an enameling operation, whereby preliminary treatment of the oiled surface for the removal of oil and subsequent pickling thereof prior to the enameling operation are avoided.

5. The method of preparing steel, iron and like metal surfaces for enameling which comprises subjecting such surfaces having an oil coating thereon to a regulated heating operation sufficient to removeV the oil and form a blue o-Xid coating thereon, whereby preliminary treatment of the oiled surface for the removal of oil and subsequent pick'ling thereof prior to the enameling operation are avoided.

6. The method of preparing sheet metal ware for enameling which comprises subjectirlg sheet metal having an oil coating thereon to a drawing operation to produce ware of the desiredshape andheating the drawn ware to remove the oil and produce a thin oXid coating thereon, whereby preliminary treatment of the oiled surface for the removal of oil and subsequent pickling thereof prior to the enameling operation are avoided.

7. The method of preparing sheetrrnetal ware for enameling which comprises subjecting the ware to a temperature of about 700 C. for about 30 producing an oxidized surface adapted to receive the enameling composition.

ln testimony whereof ll aiix ,my signature.

naYMoun nnuur 'ooo-Kn seconds and therebyv