US95017A - Self and johnx l lippincotj - Google Patents

Description

, twenty-four hours time.

ilnitmi glutrt ailment dtflflire JOHN D.- cunr, OEPITTSBURG, PENNsYLvANIA, ASSIGNOR TO HIM- A SELF AND JOHN LIPPINCOTT, or SAME PLACE.

Letters Patent No. 95,01 7, dated September 21,1869.

The Schedulerefermd to in these Letters Patent and making part of the same.

To all whom it may concern.- Be it known that 1, JOHN D. GREY, of Pittsburg,

in the county ofAllegheny, and State of Penn'sylvania,-.

have invented anew and useful Improvement in Galv'anized, Iron; and I do hereby declare that thefol lowing is a full, clear,and exact description thereof, which will enable others skilled in the art to make and use the same.

The object of my invention is to provide galvanizeg-iron of more improved quality than isnow made; an

The invention consists in preparing the iron previous to galvanizing it, in a way calculated to provide a better article in point of toughness and appearance when finished, the zinc covering being disposedmuch;

more evenly and inlarge span'gles over the entire'surof the sheet.

I am also enabled, by my improvement, to produce the same more cheaply thanis now done.

Previous to describing my improved process, I will describe the common process of manufacturing it.

In the first place, the best quality of charcoal bloomiron is generally employed, which is reduced inpacks to sheets of the desired thickness between rolls-,as ordinarily practised in rolling-mills, afterwhich it is annealed in packs in a furnace, or more generally in a close iron box, placed-in a furnace requiring about After it has been properly annealed, the sheets are trimmed to the desired size, and are now ready for pickling'in a bath prepared of water and sulphuric acid, in about the proportion of five parts of the former to oneof the latter.

The object in pickling the iron is to remove the scale formed on thesurface of the iron in the process of rolling it into sheets, it being absolutely necessary thatallthe scale shall be removed, and thesurface of the iron perfectly clean, as when anyscale remains it will not be covered in the process of galvanizing.

After the iron hasremained in the pickle long enough to have removed the scale, which generally requires from an hour to an hour and a half, and sometimes two hours, depending upon the thickness of the \SCRIB, it is taken out and washed in water to remove or destroy the acid, after which the sheets are dipped into the sal-ammonia bath, 'thence into the zinc or spelter-pot for galvanizing, as commonly practised and wellknown in the arts.

There is a positive injury done the iron by this process of removing the scale, (which is entirely obviated by iny method,) which is produced by acid penetrating the pores of the iron, ,when it is exposed too long in the bath, making it brittle or short in the grain, so

that it is easily broken when bcnt.

The scales on the sheets will vary considerablyiri thickness from various causes, and especially because they are rolleclin packs, as they must be to obtain the necessary thinness.

The sides of the outside sheets, exposed to the action of the rolls, will have a scale very much thicker than the inside of the-same sheets or the inner sheets,

and this amounts to about thirty-three per cent. of the whole, as; they are commonly rolled in packs of six sheets, and where it is thin, ten to fifteen minutes immersion in the acid bath or pickle is sufficient to remove it, but it is necessary to let it remain until the thick scale is also removed, so that while this is being slowly accomplished, the acid is attacking that portion of the sheet from which the thin scale was removed in the early part of theprocess, aml eating small. holes therein, and wasting away the iron.

The surface of the iron, as a natural consequence, is rough, and when it is galvanized, the zinc will not flow freely or smoothly upon it, which, in my opinion, prevents the formation of the large spaugles, which are desirable;

The injurious effects of sulphrn-ic acid upon iron, when it has been too long exposed to its influence, is well known, and while I use the acid bath or pickle in my process, the] iron prepared by me has a uniform scale, or very thin oxide, allover the sheet, so that it requires but ten tofifteen minutes only to remove it, the time being so short, and the act-ion of the acidso uniform, that no possible injury can result to the iron, which is smooth on its surface, and retains all its original toughness after it has been galvanized, the zinc having been deposited inthe large spangles.

My mode of making galvanized iron is precisely the same as commonly practised, with this exeeptionzl dispense with the annealing process, before referred to, thus saving time and expense, and so shorten the time necessary to pickle, that I am enabled to produce ,five times the quantity of iron cleaned, ready for galvanizing in any given time by the old process, besides running the acid bath or pickle five times as long without renewing as bythe old process, which is a saving in thecost of manufacture.

To manufacture galvanized sheet-iron by my process, I take the sheets from the rolls, trim them to the required size, and dip them in a bath of muriatic acid and water, in the proportion of about one part of the former to five of thelatter. After remaining a few minutes in the.bath,'they arctakenout and set upon their edge to drain, after which they .are placed in a furnace upon their edge, and held there by a rack arranged on the floor of the,fnrnace,.or byany other convenient means, care being taken that the surface of thesheet shall be exposed to. the heatof the furas possible.

If more than one sheet is placed in the furnace at one time, care must be taken that they in no way come in contact with each other.

The heat of the furnace being just right, in a short time the scale formed during the process of rolling will commence to raise all over the sheet, and no matter how thick it may be, theefiect will be the same.

When it is judged, by the appearance'of the sheet, that the scale is all loosened or raised, it is removed from the furnace, when the scales will leave the sheet in large blisters, and are swept off with a broom, so that by this process of raising the scale, by the means described, I get rid of any thick scale, and ,at the same 7 time anneal the iron perfectly. I

As soon as the scale commences to raise upon the sheet in the furnace, there is a new one formed be-' perfectly clean.

A man and a boy will scale as much as three to four tons of sheet-iron per day, and as fast as it is I scaled, it is pickled and galvanized, being one 0011- tinuous operation.

time that can be easily and quickly and uniformly removed in the process of pickling, for the purpose of preventing local injury to the iron, and leave the surface smooth, so that the zinc will be deposited on it in large spangles.

Having thus described my invention,

I claim as new, and desireto secure by Letters Patent 1. The improved process, herein described, of preparing iron for galvanizing, substantially in the manner and for the purpose specified.

2. As an improved article of manufacture, galvanized iron, when prepared in the manner herein spcci' fied.

JOHN D. GREY.

\Vitnesses:

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