US1630507A - Process of coating materials having an iron or steel base - Google Patents

Description

May 31, 1927. 1,630,?

L. A. WYND ET AL PROCESS OF COATING MATERIALS HAVING AN IRON OR STEEL BASE Filed Feb. 26, 1926 ln'szz'sn-r c2215..

LPate ntd May 31, 1 927.

UNlTED STATES PATENT OFFICE.

, LEO A. WYND Am) JULIAN L. scnunnnia, or rnoam, rumors.

PROCESS COATING MATERIALS HAVING AN IRON OR STEEL BASE.

Application filed February 26, 1926. Serial No. 90,868.

This invention has reference'to a process.

of coating materials having an iron or steel base such as sheets, Wires and like materials, particularly-the coating of wire used in the fence industry and for telephone and other purposes.

The principal object of this invention is to apply a heavy coating ofzinc on wire without recourse to heat-treatment, either prior to or after coating, or the use of a high grade zinc. Such a coating may be bent around its own diameter without showing the least signs of cracking or flaking and the'coating will be smooth.

The invention has for a further object to permit higher speeds to be used for the for-- mation of a heavier coating than can be economically done by any other process of which we have any knowledge.

The invention has for a further object an improved cleaning process for the wire prior to its entrance to the zinc bath andto allow the clean wire to enter and leave the bath through a clean zinc system.

Galvanized wire which is to be used for fabricating purposes, and more particularly that which is to be used in the manufacture of woven wire fencing, should have a relatively heav'y coating of zinc in order to be able to withstand atmospheric rusting and corroding conditions, and prior to our invention, so far as we are aware. this was not possible, except at an increased cost of pro-- duction. I

The universal practice for testlng the relative value of zinc on galvanized wire is by the so-called Preece or copper sulphate test. There are other tests, however, which are used for quantitatively determining the amount of spelter on galvanized Wire, such as dipping the coating in caustic solution; in a suitable hydrochloric acid solution; in a solution of hydrochloric acid and antimony chloride, and in alead acetate solution. The copper sulphate test, although not quantitative, is comparable when used under known conditions' of temperature and strength and being a quick test, and one which can be performed by anyone after a little experience, has come to be the routine testing medium for galvanized wire coating. On the basis of such tests as these. are determined the relative weights of coatings (either thin or heavy) referred to thruout this description.

At the present time, so far as we are aware, there are only three methods in use whereby these heavy zinc coatings may be,

obtained by the hot process of galvanizin The first method is to pass the wire throng finely divided charcoal as it emerges from the galvanizing bath. By such a process a relatively smooth coating may be obtained. This method. is principally used for making telephone and telegraph wire. It hasserious drawbacks, however, from an economic standpoint because the wire must travel at a very slow speed and a very high grade zinc must be used and, furthermore, the coated wire cannot be-subjected to the action of fence fabricating machines without the coating cracking or fiaking'rofi of the iron base.

The second method is to cause the wire to travel at a relatively slow speed through a zinc bath. the speed depending upon the gauge of the wire, the thickness of the coating desired and the length of the bath and then smoothing the coating by passing it between suitablev wipes. This method, too, has its economic drawbacksbecause it requires pure zinc on account of the slow speeds required and it consequently lessens the tonnage passing through a galvanized unit in a given time. The third method is to pass the wire through a galvanizing bath and then without wiping subject it to a heat-treatment. This process, too, is slower than our process and more expensive to operate.

Therefore, by the use of our invention we are not only permitted to use higher speeds for galvanizing wire but we, also, obviate the necessity of using wipes or other smoothing mediums and the necessity for heattreatment, either one or the other, heretofore considered indispensible'in galvanizing operations. Anadvantage in eliminating the wipers is that a heavier coating is permitted to remain on the wire, which in ordinary processes is removed by the wipe as the coated wires pass therethrough. It will, therefore, be apparent to those skilled in the art that the higher speed can be used because it is not necessary for the wire to be wiped nor to be immersed in a molten salt bath, nor is it necessary to pass the coated wire through a heat-treating furnace. By

accompanyin drawing, in which a diagrammatic view ilustrates a continuous galvanizing or coating apparatus, including a lead annealing bath; an acid bath, and a galvanizing tank adapted to contain the molten zinc bath. There is eliminated from such an apparatus the usual and ordinary wiping or smoothing mechanism, as well as a heattreating furnace used for heat-treat1ng the coating subsequent to the coating operation; also, there is eliminated the necessity for iving the wire a so-called preliminary car- Eonization before it enters the coating bath.

Our process is very simple. We have (hecovered that if a wire is given a very thorough cleaning prior to coating and if the wire is kept clean until and while it enters the coating bath and also kept clean as 1t leaves the coating bath and the coated wire is removed from the bath in a substantially vertical direction, that a ver smooth coating will be obtained and a very eavy one at the same 7 time, which can be subjected to the most severe bending or forming operations and still leave the coating intact upon the wire.

The processes which are at present in ordinary use, and which we are about to describe,

have special reference to the lower carbon wires, though not limited to these, are used for fabricating fencin barb wire, and for furnace where the the manufacture of te ephone wire and the like.

The ordinary process of galvanizing wire consists in passing the wire through molten lead or through an annealing furnace which accomplishes the same purpose, cooling the wire and then passing it into preferably muriatic acid where it is subjected to a cleaning operation. It passes from the muriatic acid through a flux, then over a drier and into the coating bath. As the wire leaves the bath it passes between asbestos wiping means of some kind-either pressure or lever wipes and these wipes remove the excess zinc; in some cases as much as 50% of the coating which adheres to the wire. This leaves a very thin coating on the wire.

In the manufacture of te phone wire,

which requires a .heavy coatin the'wire is passed very slowly through a ath of high grade zinc and as it leaves the baththe wlre passes through a bed of charcoal and tallow, which wipes and smoothes the coating but does not wipe it as heavily as the ressure wipes mentioned before. In the erman process, United States Letters Patent No. 1,430,648, the wire passes through the coating bath and as it emerges from the bath the wire passes over a skimming arrangement which does not materially remove an coating, other than removing the dross an skimmings carried over and then passes into a heat-treatment, to which the wire is subjected, smoothes the coating and makes it malleable and flexible.

Another method for applying a heavy coating to wire is the method where the wire is subjected to a so-called preliminary carbonizetion before it enters the coating bath. This preliminary treatment may take place in a molten bath of some salt, or some combination of molten salts, and is claimed to allow a heavy coating to be carried on the wire which will be flexible. However, by this method it is also necessary to pass the wire through a wiping arrangement of some kind. By our process the wire after being sub jected to the usual annealing is passed into a usual cleaning solution, where it is subjected to a heavy current, approximately 110 volts D. (3., the wire being in contact with the ositive side of the current and a sheet of ead or some other suitable material being connected to the negative side of the current. This current drives any foreign matter off of the wire and leaves the wires extremely clean, especially from the action of the cleaning solution, which is extremely vigorous and activated when the current is passed through it. The wire then passes directly 10? the cleaning solution into the coating at t The wire enters the coating bath through a clean zinc surface and after passin through the zinc emerges from the bati through a similarl clean zinc surface. The wire leaves the bat without passing through any wipin skimming or smoothing means of any ind and is con noted in substantially a vertical direction after leaving the bath until the coating has set, after which the direction of the wire may be as desired.

No other process is known to us whereby a heavy coating of prime western zinc may be applied to wire, and which is flexible, ma leable and smooth, except the Herman process, United Stat Letters Patent No.

1,430,648, hereinbefore entioned. Prime western zinc is the usual zinc used for coating is desired, such as for telephone or telegraph wire, where the coating is r uired to stand a bend around a mandrel twe ve times the diameter of the wire, in which case recourse must be had to the use of a very high grade zinc such, for example, as pure electrolytic zinc or the equivalent thereof. The

difference between the high grade zinc and the prime western zinc is, of course, well known and understood by those skilled in the art. By the ordinary processesof applying such coatings prime western zine will not stand this bend test, as the coating will crack and eel off the wire u on subjecting it to theshghtest amount of ending.

The bending properties of wire coated by our process are remarkable in that the coated wire may be wrapped around its own diameter, then unwrapped and again wrapped around its own diameter without apparently affecting the coating in any manner. There is no other p ocess known to us of any kind whereby this may be done with a heavy prime western zinc coating.

In order to keep the surface of the wire clean at the entrance and-exit ends of the coating bath, we apply small amounts of salammoniac or some other suitable material at suitable intervals in order to keep foreign matter removed from said surface.

We are aware that the method of clean-' ing per se is not new, nor is the addition .of salammoniac to zinc baths new, nor is the removal of the wire from the zinc bath in substantially a vertical direction new, but the process as described by us, we believe, is new and produces results heretofore considered impossible with a coating of prime western zinc, and which could be produced with a very high grade zinc only under very carefully controlled conditions, which are far more expensive to operate than our process.

Our process is the cheapest one known to us for producing heavy zinc coatings, and

more tonnage per coating unit can be obtained than by any other process known to us for producing heavy coatings of zinc on wire.

The diagrammatic view accompanying this descri tion shows a preferred form of apparatus by means of which the within describedprocess may be practiced, and is ofiered to show a mode of application in which an annealing furnace 1, a cleaning bath 2 and a coating tank 3 are placed insubstantially the relative positions they will occupy when emplo ing the process. A wire A is shown threa ing through in the act of being coated.

, At the entrance end of the cleaning bath there is illustrated a positive contact 4 with which the wiresA engages, and within the cleaning bath 2 there 1s provided a ne ative connectlon 5, which may be prefera 1y 8. lead sheet, arranged across the bottom of the cleaning bath and within the cleaning solution. These elements 4 and 5, as, of course, will be understood, are connected in a suitable manner to a source of electric supply not shown.

The coating tank 3 is provided at its entrance end with a compartment 8 and its exit end a similar com artment 9. These compartments are both ormed by means of aprons 10. Above the compartments 8 and 9 are arranged feedin receptacles 6 and 7 respectively, containlng suitable mechanisms, not shown, by means of which a suitable amount of salammoniac may be added at suitable intervals to compartments 8 and 9 respectively.

The amount of salammoniac added, and the intervals at which it is added, depends ling, but in any case the amount added is very small.

In substance, our process consists in producing a heavy, flexible and malleable coating of prime western zinc on wire without recourse to a heat-treating process and in which we eliminate the usual wiping or smoothing or skimming mechanisms, or heat-treating apparatus for the coating. It is obvious, of course, that as we produce such a coating, as has been described, using prime western zinc that we can readily do so using a high grade zinc.

The coating which is formed on the wire by our process, using .prime western zinc, is extremely malleable and flexible and has a very bright silvery color,'wh ich it retains for a long period of time. This coating has properties heretofore considered impossible to obtain with prime western zinc, and which prior to our invention has been impossible to duplicate by any process known to us. It is true, of course, that the heat-treating process of Herman, United States Letters Patent No. 1,430,648, produces a malleable coating using prime western zinc but it is not as malleable or flexible as the coating produced by our process and we have eliminated the necessity "for heat-treating the coating.

The terms and expressions which we have employed are used as terms of description and not of limitation and we have no intention in the use of such'terms and expressions of excluding any equivalent for the features shown and described, and recognize that various modifications are possible within the scope of the invention claimed.

This application is a companion to the application filed by applicants on March 20, 1926, for a galvanizing apparatus bearing Serial No. 96,301.

I What we claim is 1. A process for applying smooth zinc coatings to iron or steel wire, independent of wiping, which consists in subjecting the wire to an activated cleaning prior to its entrance to a coating bath, passing the wire thru the coatin bath, the entrance of the wire and the exit of the wire from the coating bath being through substantially clean zinc surfaces.

.2. A process for applying smooth zinc coatin s to iron or steel Wire, which consists in subyecting the wire to an activated cleaning prior to its entrance to a coating bath, passing the wire thru the coating bath, the entrance of the wire and the exit of the wire from the coating bath being through substantially clean zinc surfaces, and conducting the wire from the bath in substantially a vertical direction whereby wiping is ob-,

viated.

3. A rocess for a plying heavy flexible, malleabe and smoot coatings of zinc to iron or steel wire independent of wiping,

qmalleab e and smooth coatm which consists in subjecting the wire to an activated cleaning prior to its entrance to a coating bath, passing the wire thru the coating bath, the entrance of the wire and the exit of the wire from the coated bath being through substantially clean zinc surfaces.-

4. A process for applying heavy, flexible, malleable and smooth coatings of zinc to iron or steel wire, which consists in subjecting the wire to an activated cleaning prior to its entrance to a coating bath, passing the wire thru the coating bath, the entrance of the wire and the exit of the wire from the coated bath being through substantially clean zinc surfaces, and conducting the wire from the bath in substantially a vertical direction whereby wiping is obviated.

5. A process for applying heavy, flexible, malleable and smooth coatings of prime western zinc to iron or steel wire, indeendent of wiping, which consists in subecting the wire to an activated cleaning prior to its entrance to a coating bath, passing thewwire thru the coating both, the entrance of the-wire and the exit of the wire from the coated bath being through substantialy clean zinc surfaces.

6. A rocess for applying heavy, flexible, of prime western zinc to iron or stee wire, which consists in subjecting the wire to an activated cleaning prior to its entrance to a coating bath, passing the wire thru the coating bath, 'the'entrance of the wire and the exit of the wire from the coated bath being 40 through substantially clean zinc, surfaces, andconclucting the wire from the bath in substantially a vertical direction whereby wi in --..,i s obviated.

X process for applying smooth a zinc coatings to 'n on or steel material, independent of wi ing; which consists in subjecting the material to ail-activated cleaning prior to its entrance to a coatin bath, passing the material thru the coating ath, the entrance of the material and the exit of the material from the coating bath being thru substantially clean zinc surface.

LEO A. WYND. JULIAN L. SOHUELER.

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