US1430649A - Process of coating and treating materials having an iron base - Google Patents

Description

I. I.. HERMAN. PROCESS 0F COATING AND TREATING MATERIALS HAVING AN IRON BASE. APPLICATION man MAR. 192.2.

31,430,649, mamma. OCI. 3, w22.

nucnfot Patented @cto 3, T922..

JOSEPH L. HERMAN, 0F PEURIA, LLINOTS.

PROCESS 0F COATING ANDy TREATING MATERTALS HAVEN@ AN IRON' BASE.

Application led March 6, 1922.

Be it known that l, JosnrH L. HERMAN, a citizen of the United States, a resident of Peoria, in the county of Peoria and State of lllinois, have invented new and useful` Improvements in Processes of Coating and Treating Materials Having an lronBase, of which the following is a specilication.

This invention has reference to a process of coating and treating materials having an iron base and particularly the coating and treatment of wire used in the fence industry and for telephone and other purposes.

The principal object of the invention is to subject the coated material to a simultaneous heat-treatment and annealing during' the continuous process of coating such material and preferably immediately upon the material leaving the molten coating bath in which the material is immersed or through which the material is moving. -Such heattreatment has for its object an improved coating which will be more resistant to atmospheric rusting and corroding conditions than is'oi'dinary galvanized wire, and which further will permit a heavier coated wire to be used in wire fabricating machines without -causing the coating to crack or Hake off, as is the case with heavily coated galvanized wire coated by ordinary processes; the annealing of the material being for the usual softening purposes.

The invention has for a further objectto subject the coated material to a heat-treatment o1 to a simultaneous heat-treatment and annealing in an air or oxygen free atmosphere.

The invention has for a further object to apply a heavier coating on the wire with a shorter immersion in molten zinc than is the case with ordinary galvanized wire carrying the heavier coating.

A further object of the invention is to permit the use of higher speeds for galvanizing wire than can be used under the ordinary galvanizing process where heavier coatings are desired and at the same time causing a heavier coating to be formed on the wire. v

This application is a companion to the application for patent filed by me on F ebruary l0, 1922, bearing Serial Number 535,660 for a process of coating and treating materials having an iron base. The invention herein differs. from that disclosed in said pending application in that the usual Serial No. 541,561.

annealing step is combined with the heattreatment and such heat-treatment preferably takzes place in an air or oxygen free atmosphere.

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 must have a relatively heavy coating' of spelter in order to be able 65 to withstand atmospheric corroding conditions, and before my invention was developed this was not possible except at a much increased cost of production.

The universal practice for testing the relative value of spelter on galvanized wire is 'by the so-called Preece or copper sulfate test. There are other tests, however, which are used for quantitatively determining the amount of spelter on galvanized wire, such as stripping the coating in caustic soda solution; in a suitable hydrochloric acid solution; in a solution of hydrochloric acid and antimony chloride, and in a lead acetate solution. The copper sulfate test, although so not stri ctly quantitative, is comparative when used under known conditions of temperature and strength, and being a quick test, and one which can be performed by any one after a little experience, has come to be the routine testing medium for galvanized wire coatings.

At the present time there are only two (2) methods in' use whereby these necessary heavy zinc (spelter) coatings may be obtained by the hot process of galvanizing.

The first method is to pass the wire very slowly as it emerges from the galvanlzlng bath, through finelydivided charcoal. lBy such a process a smooth, thick coating may be obtained. This method is used for making telephone wire. llt has serlous drawbacks, however, from an economlc standpoint, because the wire must travel at a very slow speed, a very high grade zinc must be used, and, furthermore, the coated wire can- 10o not be subjected to the action of wire-fence fabricating machines without havmg considerable of the zinc coating'crack or flake off the iron base. The second method 1s to cause the wire to travel at relatively slow 105.

speeds, through a bath of molten spelter, the speed depending on the gauge of wire, the

vthickness of coating desired and the length of the molten spelter bath, and then wiping the wire by passing it between suitableA c wipers. In other words, a wire will have a heavier galvanized coatlng, as measured by means ,I -treater and annealer is heated all the the copper sulfate test, the longer it remains in the molten spelter. v This latter process,

too, has its economic drawbacks, because of the slow speeds required, the long spelter pans necessary and consequently the lessening of the tonnage passing through a galvanizing unit in a given time.

In the accompanying drawing there is illustrated diagramatically the usual or ordinary continuous galvanizing or coating apparatus, 'except the annealing furnace which is not laced as it is ordinarily, and includes the acid bath, flux7 bath, coating or galvanizing bath, and my heattreater associated therewith, which in this instance is used as a `combined heattreater and annealer. There is also illustrated a means whereby an air or oxygenl free atmosphere may be maintained within myl heat-treater and annealer, wherein both ends of the heat-treate'r and annealer are sealed; one, end being submerged below the surface ofthe coating bath and the other being submerged below the surface of water, oil or some other sealing Thus when my combined heatoxygen in the conined airis soon used up and both ends being sealed no more air can enter so long as the heat is mainl tained.

My process consists preferably in treating wlre as is usual in the 'ordinary contint scribed, which follows the coating step, and

" phere.

preferably in an air or oxygen free atmos- I have discovered that if after the wire leaves the coating bath it is subjected to a temperature of approximately 1250O F. I not only havea superior coated wire but said wire is also annealed. I realize that annealing per se is not new, but is new in conjunction with my heat-treatment of the coated wire. I' also realize'that the annealing temperature will vary for diHerent carbon contents or kinds of wire,` or whether the annealing is to relieve the strain of bench hardening that comes from the cold working of the wire, o r whether from some other source. For example, if -a bench hardened No. 12gauge wire (American steel wire gauge) the carbon content of which is approximately 0.12% -is passed through molten spelter, the temperature of whichis approximately 870 F., for-approximately two seconds and then through a heat-treater, preferably-a heated tube held at approximately 1250o F. and preferably free of air or oxygen, for approximately ten seconds, and with lor without wiping after leaving the heat-treatment, a wire is coated which will stand approximately four 65.

one minute immersons in copper sulfate;

` must be annealed.` Heretofore this step Madea@ unsalable product', and cannot be successfully used in fence fabricating machines.

What I have described for No. l2 gauge wire is also true for other gauges of wire, some of the larger` gauges such as No. 9 standing ofttimes many more than four copper sulfate immersion tests. I do not, of course, limit myself to the speeds and temperatures above given because I have found that I may vary the speeds by controlling `the temperatures; for example, if I want the wire to travel at a high speed, then I use higher temperatures, and vice versa, as clearly described in my copending application, above referred to.

Heat-treatment as employed by me has reference to such treatment as will produce a physical or chemical change in the material undergoing treatment. Annealing is'also a heat-treatment and refers to the softening of hard wire, such as bench hardened wire. It is well known that when wire is drawn it becomes harder after each reduction, due to physical changes which take place within its structure. may be relieved and the v vire made soft by heating the wire to a much lower temperature than would be the case if the hardness was due to carbon hardness. For example--n a 0.12% carbon wire it is well known that in order toanneal for carbon hardness it is necessary tor heat the wire in the neighborhood of 1650o F., whereas This hardness,

heating to around 1250o F. will be suicient i to relieve the hardness caused by the-drawing of the wire and expressed by me asp.

bench hardness.

It is well known that hard wire 'is un-` suitable for use in many kinds of wire fabl'- For this reason the wire has taken place preceding the coating o the wire, but in my new process, I do this sub.- sequent t`o the coating of the wire and in Lconjunction with my heat-treating. This, of course, eliminates one complete stepl in the continuous galvanizing process and effects considerable economies from ya cost standpoint. f

When the ywire leaves the coating bath and is not wiped or smoothed an uneven brittle coating is theresult. I therefore subject the coated material to a suitable heatcating machines.

treatment such as I have previously described. The result of this heat-treatment is a smooth, even, pliable coating and due to the fact that the coating was not wiped there is a heavier coating on the Wire than is the case with ordinary processes. Furthermore, when galvanized coatings are subjected to high temperatures in the presence of air or oxygen the zinc of they spelter burns to Zinc oxide. For this reason I find it preferable to exclude air or oxygen from my heat-treater.

Wire galvanized by my process has an exceptionally smooth coating even Without the use of Wipes. This gives me another advantage, in that I eliminate the production of reachers which, With the ordinary galvanizing practice are always produced and as such are valueless except as scrap. Furthermore, it is not necessary for me to use excessively long spelter pans, as I have eliminated the necessity for long immersion of the Wire in molten spelter:

By eliminating the initial annealing step and coordinating the annealing and heattreatment after coating, I avoid the necessity of using a special furnace for the initial annealing and thus effect considerable economies over the lusual and long established process.

and continuously moving the material through the heat.

\ 3. 'Ihe process of treating un-annealed metal coated materials having an iron base which consists in simultaneously subjecting the material to a heat-treatment and annealing in an air or oxygen free atmosphere.

4c. rlShe process of treating un-annealed metal coated materials having an iron base which consists in simultaneously subjecting the material to a heat-treatment and annealing in an air or oxygen Jfree atmosphere, and continuously moving the material during such heating and annealing.

5. rIhe process of treating un-annealed metal coated materials having an iron base which consists in simultaneously subjecting the material to a heat-treatment and annealing.

6. The process of treating un-annealed metal coated materials having an iron base which consists in simultaneously subjecting the material to a heat-treatment and annealing, and continuously moving-the material during such heating and annealing.

7. The process of galvanizing Wire, which consists in continuously moving the Wire and during such movement subjecting the same, firstto a molten bath of spelter and upon leaving the bath subjecting the coated Wire to a heat-treatment in an air or oxygen free atmosphere.

8. rllhe process of galvanizing lin-annealed wire, which consists in continuously moving the Wire and during such movement subjecting the same, irst-to a molten bath of spelter and upon leaving the bath subjecting the coated Wire to a simultaneous annealing and heat-treatment in an air or oxygen free atmosphere.

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