US47506A - Improvement in the manufacture of iron and steel - Google Patents

Description

G. PARRY. MANUPAGTURE of' IRON AND STEEL,

No. 47,505. Patented Apr. 25, 1555.

UNITED STATES -P-AfrniwrA (hai-rien.4 i

GEORGE PAR-BBLv OF EBBW-VALE TRON WORKS, ENGLAND.

`Specification forming part of Letters Patent-No. 47,506, dated April 25, 1865.

.To all whom it may concern:

Beit known that I, GEORGE BARRY, of Ebbw-Vale Iron IVorks, in the county of Monmouth, furnace-manager, a subject of Her 'Britannie Majesty, have invented Improvements in the Manufacture of Iron and Steel; and I do hereby declare `that the following is a full and exact description of my said invention.

This invention has for its object the production of a superior bar or wrought iron to that obtained in the ordinary manufacture of iron, as well as the production of cast-steel in large masses of a superior quality to that obtained by the direct decarbonization of crude pigiron, as now carried out. To accomplish these objects, I take wrought-iron which, from having previously undergone the puddlingprocesshas been purified by the expulsion of sulphur and phosphorus; or I take wrought-iron scrap and introduce it, together with coke or other fuel and proper fluxes, into a blast-furnace similar in form to that ordinarily used for melting pig-iron, but so arranged with respect to the tuyeres as to insure the maintenance cfa much higher temperature in the furnace than is required for merely melting the iron. By this means I am enabled to effect the rapid and economical carbonization of the wrought-iron under treatment. When -thus carbureted, I run out the iron from the converting or blast furnace into any suitable form, and submit it to the puddling process, by which means a further portion of sulphur and` phosphorus is removed, and the iron is in-` creased in strength and value. This iron may, if thought desirable, be again carbonized and puddled again for the third time.

In the accompanying drawings, Figure 1 shows in vertical section the furnace which may be employed for converting or carbonizing wrought-iron. Ais the opening for charging; B, a l tuyere blowing horizontally; C, a smaller tuyere inclined downward at an angle of about thirty to fortyfive degrees. D Dare tnyeres placed near the bottom of the furnace for #blowi/ug air through the metal when required, (two of which only are shownin the drawings.) E E are blast-boxes for supplying the tuyeres D D, and which are connected with the blowing-engines by pipes F F.

In carbonizing the' wrought-iron, I propose' y to make it take up two per cent. or thereabout ofy carbon from the coke, when it will be ready to undergo the subsequent treatment of puddling, whichI will convert it into what I term` puriiied wrought-iron. Sniicient fuel hav# ing been supplied to the furnace for the purpose` of getting up the heat, I charge the furnace with'` about seven hundred weight of coke (with suilcicnt lime`to iiux the ash of the coke) to every ton of wroughtiron,applying these materials y in successive quantities of from one and a quar-l.

ter hundred weight to one and a half hundred weight of coke to four hundred weight of iron, which will be found a convenient quantity for each charge. The converting-furnace being filled and the blast put on, the furnace should be kept nearly full during the continuance of the operation, or the iron will not have taken up a suiicient dose of carbon, and unless this l be done the subsequent treatment of the iron in the paddling-furnace will be useless, the presence of a certain amount ofcarbon in combination with the metal being necessary to produce the boil, without which no ei- `cient reiining ot' theiron will take` place. With a small furnace two and a half feet square, roundedat the angles, and from ten to fteen feet high, blown by one horizontal tuyere having a nozzle of two and a half inches diameter, and one inclined tuyere of oneginch and a quarter diameter, with a pressure of -blast of two pounds and a half to three pounds on the square inch, Ihave been en abled to earbonize and run out one ton'of iron per hour.

In carrying out this part of the process I prefer to blow vdown into the iron through one l or more -f-tuyeres, C, (not using the-lower tuyeres, D D.) The nozzles of these tuyeres C maybe changed for others of largeror smaller bore in a few seconds, when required,

the exact amount of blast required being soon ascertained by alittle practice, and the want of a sufficient blast being indicated by the carbonized iron, when Irun off, notbeing suf ciently duid. of the furnace, and H the tap-hole. With converting-furnaces of larger dimensions the number of bothhorizontal and inclined tuyeres must be increased, so as to diuse the blasts of air more uniformly over-the enlarged area of the furnace. The whole of the tuyeresmay be inclined downward with nearly the same' eifect, if thought desirable, but must be put G is the cinder-hole at theback y at alesser angle of dip. I prefer, however, they` irond'oes not admit of slag being formed to any extent Whenair is. blown into it while in the Huid state; but the oxide formed would pass out at the top of the furnace as a dense brown smoke and entail a loss, were it notthat the column. of incandescent .fuel above reduces itto the metallic'state and intercepts it. I find that a height of furnace from eight to ten feet is sucient to. effect this reduction and prevent the loss of metal by sublimation. When the charge of scrap'or puddled iron has been subjected to the blast a sulicient time to bring down, say, a ton of the A'carbonized metal, I tap the furnace and run the metal into molds, as is usually done with pigiron intended for puddling, and I otherwise treat it in a similar manner to iron prepared for puddling-` that is to say, I now submit the carbonized, Wrought, or scrap iron to the operation otpuddling in an ordinary puddling-furnace, and by that means cause it to give up or part with the impurities remaining therein after the first puddling process. The metal .I remove as puddled balls, which may then .be submitted tothe ordinary rol1s,for the purpose of being reduced to the form of merchant or other bars. This. completes (in general) the process of making my purified Wrought-iron, which may be subsequently-converted into cast-steel in the manner presently t be described, or applied to other uses. When, however,a still purer quality of iron is required, I repeat'the converting or carbonizing process, and then subject the metal to the 'pnddling process, as before.

I would here remark that by taking the thoroughly-puddled iron from the furnace in small balls or pieces the cost of rolling the same into bars and cutting those bars up 'by shears into pieces suitable for undergoing a second carbonization, or for conversion into hard or soft steel,will be avoided. 'lhe pieces .of Wrought-iron intended for Carburation should not be.too large-.not much exceeding the. size of. a railway-bar cut up into lengths of four to six inches. Cinder-iron, of which nearly the whole of the railway-'bars laid down have been manufactured, becomes, by suiicient carburation in the converting-furnace and subsequent puddling, equal in value to the best brands of mine-iron, and vmay be. used `for the like purposes, or be converted into cast-1` steel.' rI hus the iron rails new in use, as they successively become worn'out, may by this 1n vention be converted-into durable cast-steel rails'.

In order to convert baror scrap iron into cast-steel, I introduce into the-converting or blast furnace a smaller proportion of coke or fuel than is required for manufacturing the purified wrought-iron. The proportion may be so regulated, as to communicate to the wrought-iron the desired degree of carbon known to vexist in the various classes of caststeel, from hard cast-steel to soft cast-steel, and I run thissteel out of the furnace into ingots or into any desired'forms. In the manufacture ofn cast steel from.

wrought-iron I use the saine kind of converting-furnace as that described for makingY the more highly-carbureted metal; but I reduce the quantity of coke vto about five hundred Weight te every ton of wrought-iron used when making a hard steel,and to about four and a half hundred weight when producing a soft steel, theproportions varying.. somewhat ac'- cording to the quality of the coke or other fuel used.' y

In ymaking hard steel I prefer using the tuyeres B and C, Fig. I, without the tuyercs D D; but I increase the size of the nozzle of the.

blowing-down tuyere C, making it about one` and a half to' one'and three quarter inch in diameter, so as to discharge more blast=into the metal at the bottom of the furnace than is required when preparing the carbureted iron" for the puddling process. The proper quantity of air required will be found bya little practice, for if too little be blown down the..v

steel will prove deficient in fluidity.

In making soft cast-steel I prefer using two or more ofthe tuyeres D D, together with the ordinary tuyere, B, ofthe blast-furnace, with or without the tuyere C. The tuyeres D D being below the surface of the iiuid, converted wrought-iron or molten steel must be sup'- plied with blast of 4sufficient pressure to force through the head of metal, and I find that three pounds to the square inch is enough' for every six inches of depth of metal. The state of the metal in the bottom ofthe furnace may be partly judged of -by passing a small rod ofiron' into it through the tuyere C, or more ex-v actly by tapping out a small quantity of it..

`If too hard, the blast should be slackened. on the tuyere B, the blast on the other tuyeres being .either continued unaltered or some- .what increased. If found too soft, a portion ofihard steel or any pure pig or carbureteu iron may be run into it through the tuyere C, Where alsoany inanganesic or other desirable alloy .may be passed in (by moving the blowpipe back) just previously to tapping the furnace. It is best not to run the steel direct from the furnace into the molds, but first into a funnel, from whence it may bepassed out with greater` regularity'. on removing the funnel-stopper, as is usually done when large. vcastings of steel are made from the accumulated purings of numerous crucibles; The steel may also be mixed or alloyed w1th any other metals or substances in this funnel, 1n-

. stead of in the furnace.' The molds may-be placed on a turn-table, which is made to` revolve beneath the funnel, thus` bringing each.

mold in succession beneath the oriiicev of the funnel to be filled,- and the funnel made large enough to receive the contents of two or more converting furnaces, if required. Instead,

however, of making soft steel in the converting-furnace, as just described, I prefer to produce it at two operations. Thus I first make a hard steel in-the converting-furnace, and then'run it out into another furnace orreceiver, where I reduce it to the required de` grec of lsoftness by passing air through the fluid metal from below, as first pointed out in the specification of an English patent grantcd`to Mr. J. G. Martien, dated September 15, 1855, No. 2,082, for the treatment of crude pig-iron; or I blow air down on the surface of the metal, as practiced in the old refineries,. andshould the steel now be found too soft for the purpose required, I harden it by the addition thereto of a .proportion of the hard steel in a fluid state from the converting-furnace.

Fig. 2 represents in sectional elevation the furnace or receiver into which I run the hard steel from the converting-furnace. I would here remark that it may be convenient to makethis furnace of suir'iicientcapacity to hold the runnings of two ormore converting-furnaces', as by that means large masses of cast- Sbeel may be readily produced. E E are two blast-boxes, of which there are several, placed round the furnace. They are made either cylindrical, to hold but one tuyere each, or are widened out around the furnace, so as to hold a greaterl number. G G is the main blastpipe, which passes round the furnace and feeds the b1astboxes by the pipes F F. D D are two of the tuyeres for blowing air through the molten met-al, and II the tap-hole for discharging it when reduced to the required degrec of softness. may be made of two truncated cones of sheetiron joined at the base, (or better of a curved or-parabolic form, as shown in the figure.) and lined with fire resisting material, which is shown at I I I. The charge of hard steel or carbureted wrought-iron is run in a molten state into the furnace through the opening J at the top after the blast has been turned on.

The furnace may conveniently be heated by means of a gas blow-pipe, shown in vertical section at Fig. 3.I A is the fuel-chamber of this blow-pipe, charged up to the line D with breeze or small cokes, cinders, or refuse from the fires,together with a portion ot' lime to flux the clinker and ash, .and which runs out at the cinder -hole C. B is a blast pipe for [.g'cneratingl the gas, and H another for effecting thc combustion of the gases while passingthrough the pipe [to the furnace, Fig. 2, or thc blast of air for consuming the gases may be introduced at K directly into the pipe I. '.lhis gas-furnace is lined withgtire-brick and closed witha brick cover, L, or it may be surmounted by -a charginghopper. Thepipe I is also lined with loam or other bad conductot' of heat. This gas blow-pipe is mounted This furnace or receiver on wheels for the convenience of removing 'it from the furnace, Fig.` 2, when desired. After a few minutes blowing into the receiver (the exact time requisite being very accurately ascertained by the workman after alittle expe-` rience) the steel will have become sufficiently softened,.and may be tappedand run out into a funnel and dealt with as before described.

Previously' to tappingthe furnace, alloys may be run in at thetop J, or, what is bet-ter, the alloying material may he `poured intothe fun nel as the steel is running.` It' may also be hardened when made too soft `by the addition f hard steel, or of any pure pig orcarb'ureted iron (which may alsocontain'the alloy) in t-he same manner. v

In the manufacture of cast-steel directfrom crude pig-iron, as lately introduced, by removing a portion of the carbon. sulphur and phosphorus remain behind, and it is difficult to get crude pig-iron free from these injurious elements. In thisiprocess for manufacturing cast-steel by adding carbon 'to wrought-iron, (which had previously been puddled,) nearly all the pig-iron produced in `this country becomes available for the manufacture of easti steel in the converting-furnace, the greater contained in the pig-iron. It will thus be seen that when such purified iron has beensufciently carbureted in` `my converting-furnace and again puddled, the impuritiesA above named become almost entirely removed, and the iron is fitted for conversion into best caststeel by this invention.

I have found it desirable,` when using sulphury coke in the converting-furnace, `to add, as much lime as the ash will bear as a iiux, but not such an excess as to thicken the cinder and clog up the furnace. The coke should also, when in a drystate, be immersedin brine or a solution of carbonate of soda for a few days previous to use. y The brine or `carbonate of soda, when thusintix'nately diffused th rough the whole substance of the coke, will eectually seize the sulphur and carry it off in the slag, and thus prevent the` contamina.-`

tion of the metal. Carbonate of soda or any other cheap alkali (in a dry state) may also be i introduced at the top of the furnace with the charges;- but the use of alkalies for seizing the sulphur of the coke forms no part of my invention. 1 v y Whenthe kind df wrought-iron called puddied steel is used in the convertinglfurnace for conversion into cast-stcel,'the proportion of fuel expended will bel'ess than that given The same remark also applies when hot-blasts are employed.` In the latte-r case above.

the tuyeres,whioh are placed above the surface of the metal, may be of the kiu well known as vwater-tuyeres; but with coid-basts, brick or refractory fire-'stone tuyeres are best. The tuyeros pla-ced beloir the surface of the metai are conveniently made of Very thin sheet-iron, (bla-ek plate,) slightly tapering,

'having good fire sand or clay (siiioious underoiays of the coal measures) rammed around them, or as small a proportion as possible of the fet orzthiminous `clays mixed with powdered white sandstone, as well as for the 1in` ing of the furnaces. Y Y v Having now set forth the nature'of my invention of improvements in thema-nfacture ofiron and steel, and explained the kind of apparatus I employ in carrying; the same into effect, l' wish it to be understoofl met I do not -eleim. suohvapparatus as any part 'of my in-

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