US2097472A - Process of flame treating coated materials - Google Patents

Description

PROCESS OF FLAME 'IAREATIN-G .COATED MATERIALS Filed Oct. 4, 1934 Patented Nov. 2, 1937 UNITED ASTATES PATENT oFFlci-i I PROCESS OF FLAME TREATING COATD MATERIALS AJulian L. Schueler, Kokomo, Ind., assigner, by mesne assignments, to C. W. La Porte, Peoria, f lll., and J: L. Schueler, Kokomo, Ind., trustees Application ctober 4, 1934, Serial No.'746,859

Claims.

This invention relates to a process for the treatment of coated iron and steel materials. It is applicable particularly to coated wires, round', at, shaped, strips, etc., whether or not they be in- 1 5 tended for fabrication. In the ensuing descrip- 15 rial, to render the coating more smooth and even,

and otherwise to impart a beneficial effect to the coating. These and other objects are attained by the application of ames tothe coated material for a period of time and under conditions of temperature, allas hereinafter set-iout. An apparatus suitable for this purpose is illustrated in the accompanying drawing wherein is shown a number of wires emerging from a coating bath to travel in parallelism through a iiame wave which 25 is shown as undulating between upper and lower deecting surfaces illustrated in vertical section to better exhibit the construction. l In carrying out this invention, particularly in the case of wires, I utilize a pan P in which is 3QV contained a bath B of molten zinc at a suitable galvanizing temperature, perhaps about 860 degrees F. Through this bath may be drawn a number of wires w in parallelism. Immediately upon leaving the bath, each wire i s taken through 35 a coating regulator R which removes `dross, skimmings, and grosser articles, and also reduces the amount of coating remaining on the wire to'a point at which a benecial treatment by arnes may be practiced. The weight of coating material 40 so removed from each wire may perhaps be 50% or more, the amount being subject to the setting of the regulator.

Upon leaving the coating regulators the wires travel side by side through a ame apparatus 45 which may comprise upper and lower deflector surfaces U and L, respectively. By preference, these surfaces are sloped upwardly very slightly,

as shown in the drawing. These deflector surfaces which desirably are constituted by refrac- 50 tory blocksdeine a. space which is open on all to being guided by rollers G on their way to take-*r 55 up reels. The upper and lower deflector surfaces confined practic are adjustable relative to each other, so that the space between them may be varied as desired.l

Projected from a line of burner openings O into the space from the end thereof which is proximateto the bath is a waving llame sheet F which, 5 as shown, proceeds downwardly and forwardly from the upper deflector surface to strike thel lower deector surface, and then rebound therefrom, and again rebound from the upper deflector surface, and so on thrdughout the length of the t ame apparatus. The flame sheet which thusv undulates throughout the space between the two deflector surfaces is impinged against the several wires on all 4sides thereof during their travel through the name apparatusi Further description of the apparatus per se need not be given here inasmuch as a full explanation thereof appears in my Reissue Patent No. 19,209 dated June 12, i934.

It is my experience in the flame treating of zinc coated wire that very satisfactory results may be 20,

obtained with certain changing temperature conditions for a' brief interval of time. It is accordingly 'with this aspect of my invention that the following descri tion is particularly concerned.

I nd it ad ntageous to utilize a flame apparatus in whic may be maintained a continuous elongated iia e sheet of between eight and eleven feet in length. The flame sheet so projected is if not entirely, within the space defined between the upper and lower de- `flector surfaces which accordingly may be of substantially the same length. In practice, these surfaces radiate considerable heat which augments that of the flame sheet which latter, however, is alone responsible 'for the smoothing andl 35 evening of the metallic coating so treated.

It is desirable that a temperature of from 2000 degrees F. to 2400 degrees F. should obtain at the point where the waving flame sheet first strikes the deflector surfaces. At the exit end of the 40 apparatus, this temperature is, by preference, much lower, perhaps around 1700 degrees E. Accordinglyjtheremay be a differentialrange of three. to sevenhundred degrees F. between the two ends ofthe flame sheet, the point of highest temperature being adjacent the burners from which the flames areprojected.

Between the length of the flame, the temperature of the name, the speed of wire travel through the llame, and also the gauge of the wire itself, there is a close relationship which determines the character of the result produced by the present flame treatment. As tothe speed of wire travel and its consequent duration of treatment by the flame, the following is noted z. g`

According to my process, it is feasible to galvanize concurrently a number of wires varying widely1 in size, and also to treat successfully all such wires by a flameapparatus such as hereinbefore described. The speed of travel for 9 gauge wire (.1485 inch diameter) may in commercial practice be about sixty-seven feet per minute, although I have obtained successful results with a higher speed of from ninety to o ne hundred feet per'minute. For a 15% gauge wire a commercial speed would be about one hundred fifty seven feet per minute. At the lower of these movement rates, the 9 gauge wire would travel through a ame zone of ten and one-half feet for approximately nine seconds, and the 151/2 gauge wire for approximately four seconds. At higher speeds the wire will be subjected to -flame treatment for acorrespondingly shorter time. It is accordingly optional, within a. fairly wide range, as to the speed of wire travel and the period of flame treatment that may be selected.

I have ascertained that a very benecial effect results from the action of flames on a molten coating of material, such aszinc, applied't'o a base, such as iron or steel. It is not the temperature per se which is responsible for the better distribution of the coating over the base to which smoothing of the coating which is conducive t o enhanced ductilityand adherence. ,Rather itis the flame action itself, due perhaps to its impingement upon the coating. The eiect of the a-me is satisfactory when it is applied at temperatures within the range above suggested, and also when the temperature conditions are such that there is a progressive decrease in the temperature during the period of ame treatment.

From the foregoing description it is manifest that exibility characterizes the operating conditions surrounding a successful lame-treatment such as this invention is concernedwith. Al-A superior smoothness'and evenness which comprises moving such materials at a speed dependent upon the thickness of such materials through a zone of llame treatment of predetermined length wherein the temperature of the name. treatment is progressively decreasedin the direc- 24.00 F. and 1700 F., the wire being required.

to encounter the point of maximum temperature rst.

3. A step in the process of galvanizing wire which consists .in moving the wire upon which a zinc coating is still molten through a zone of ames ranging between eight and eleven feet at a speed ranging between ftyand two hundred feet per minute, the ame temperatures ranging between 2400 F.` and 1700 F.-from one end of said zone to the other.

4. The processiofY treating metal coated materials having an iron base to produce a coating of superior smoothness and evenness, which comprises mcving the base upon'which the coating is in molten state through a zone of ame treatment of predetermined length and at a speed dependent upon the character of the coating material,- and progressively reducing byv a difierential range of 300 to 700 degrees F. the temperature of the flame treatment in the direction of movement of the coated base, the lower limit of said range being above the melting point of said coating material.

5. The process of treating metal coated materials having an iron base to produce a coating of superior smoothness and evenness, which coinprises regulating the weight of coating upon the base,`moving such regulated coated base throughout a flame treating zone of predetermined length and at a speed dependent uponvthe weight of coating material on said base, and progressively reducing by a diierentialrange of 300 to 700 degrees F. the temperature of flame treatment in the direction of movement of the coated base,

the lower limit of said range being above the melting point .of said coating material.

JUmAN L. SoHo-Erna.

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