US88479A - Charles hewitt - Google Patents

Description

' x taste-w W ttttm. 2

CHARLES HEWITT, OF HAMl LTON TOWNSHIP, NEW JERSEY.

Letters Patent N 88,47 9, dated March 30, 1869- i IMPROVEMENT IN THE 1 lJ'IDDIIhIll'G-PROCIEISS FOR THE MANUFACTURE OI WROUGH'd- IRON.

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

To all whom it may concern Be it known that I, CHARLES HEWITT, ofthe township of Hamilton, in the county of Mercer, and State of New Jersey, have invented a new and useful Improvement in the Process ofPuddlin g, in the Manufiicture of Wrought-Iron, whereby I am enabled to produce iron of a better quality than other puddling-processes will yield, and with a less expenditure of fuel, labor, time, and wear and tear of tools and apparatus.

In the ordinary process of puddling, the cast-iron to be puddled is charged into the pmldling-furnace, in the form of pigs, with about thirty per cent. of its weight of forge-cinder, and sometimes with the addition of about live per cent. of its weight of rich oxide of ironore, the ore or cinder, as the case may be, being for the purpose of aiding in decarboniziug the pi g-iron, and combining with and separating from the iron the sulphur and other ibreign matters injurious to the quality of the wrought-iron, which it is the object of the puddlingprocess-to produce from the cast-iron.

In the ordinary piuldling-process, the iron-oxide is not mingled with the mass of the pig-iron, and brought into intimate contact with it, until the latter has been under the action of an oxidizing-flame long enough to become, to a considerable extent, decarbonized, and heated sufliciently to become friable, when the pigs are broken down and disintegrated, by means of stirring-bars, operated by workmen, the disintegrated iron falling into the oxide, which lies melted onthe bottom of the hearth, being fusible at a much lower temperature than cast-iron. The heat continuing, the iron soon attains a temperature suflicient to cause it to boil in the oxide-bath, and by this means, and stirring with a bar, every part of the mass of the iron is brought into intimate contact with the oxide during the latter stages ofthe piuldling-process.

he importance of bringing the cast-iron into intimate contact with the iron-oxide, in the early as well as the later stages of the puddling-process, has been recognized, and various plans have been devised for the accomplishment of the purpose. Among other things, it has been proposed to reduce the cast-iron to a state of fine division, then mix it with the required proportion of iron-oxide, also in a state of fine division, and heat the mixture in an adjunct to the pnddling-furnace until the cast-iron is so far decarbonized as to become iufusible under'the ordinary heat of the furnace, when it is to be transferred to the hearth of the puddling-furnace, and stirred and balled up without melting in the culinary way. Such a process is described in \Villiaus English patent, N o. 7 02, dated March 8,

(last-iron turnings, borings, and chips have also been mixed with finely-divided oxide and forge-cinder, and puddlod, but the casein-on being in such a state offine division, was in such cases decarbonized and rendered iutiisible, without-being first melted.

These processes, and all others heretofore proposed for puddling cast-iron in a state of fine division' mixed with iron-oxide, also in a state of fine division, would, if practically successful, have expedited the process, and so saved the], labor, and wear and tear of tools and apparatus, but they have failed 'to producewroughtiron of as good a quality as the same materials would yield by the ordinary process of puddling the cast-iron in the form of pigs, and therefore have never superseded the common process.

This inferiority of the product, I have discovered, is, caused by the conversion of the cast-iron into wroughtiron, without being melted and mingled in a flluid state with the melted and fluid iron-oxide. When cast-iron,

inthe state of a thin fluid, is mingled intimately with fluid iron-oxide, the latter induces the separation from the iron, of sulphur, phosphorus, and other matter, whose presence would impair the strength, flexibility, or tenacity of wrought-iron made from it; but if the process of decarbonization of the cast-iron has taken place to even a small extent before melting, its fluidity is thereby lessened, and if the decarbonization has gone to a considerable extent, the melted iron will only be a thick and almost pasty fluid, incapable of being intimately mixed with fluid oxide in the puddling-furnaee,

to expose fully, or eificiently the sulphur, phosphorus, and other impurities which, it contains, and permit them to be absorbed, washed-out, or otherwise withdrawn by the fluid oxide. It is therefore import-ant to prevent, as far as possible,decarbonization of the castiron previous to its being melted and mixed-with the fluid iron-oxide.

It is one object of my improvement to retain all the advantages of the common process of puddling castiron in the form of pigs, and all the advantages gained in the processes of peddling cast iron in the form of fine granules, pieces, or turnings, mixed with finelydivided iron-oxide, and at the same time to eliminate the defects of these former puddling-proeesses.

Another object of my improvementis, the production of a better quality of wrought-iron from given materials than can be produced by any puddling-process before known. 7 V

In my improved process, I first reduce the cast-iron to coarse granules, or pieces, so that they may melt down more quickly than pigs into a. fluid state. Granules, or pieces varying in bulk from spheres of about two-tenths of an inch to one inch in diameter, with a small portion larger and. smaller than these limits, I have found, in practice, to work satisfactorily. Care must be taken, however, not to make too large a proportion of the granules too small, as, in that case, they would quickly be decarbonized, and rendered infusible, and thus prevented from melting, to secure the advan-- tages of mixture in aliquid condition with the liquid iron-oxide. I deem such a mixtureof the iron in a liquid state with the liquid oxide, indispensable to the complete success of the process.

It is important, also, that the granules, or pieces 0 cast-iron should not be too large, because, in that case, they would have to be so long exposed to the heat, to produce fusion, that the iron' would become partially decarbonized, its fluidity, when melted, lessened, and in a corresponding degree lessening its penetrability by the fluid iron-oxide, which washes out, or induces the separation of the sulphur, phosphorus, or otherimpurities from the iron, when both the oxide and iron are inter-penetrated, or are intermixed thoroughly while in a high state of fluidity.

In this improved process I also prepare, by dividing in granules, or pieces about the same size as the iron granules, a rich oxide of iron-ore, to mix with and decarbonize the cast-iron. Different kinds of cast-iron, and different kinds of ore will have to be mixed in different proportions.

In the use of common anthracite gray iron, I have found that its decarbonization could be thoroughly effected by twelve and a half per cent. of its weight of magnetic oxide of iron ore, containing about sixty-five per cent. of metallic iron.

I mix, thoroughly and evenly, the granulated iron and ore in -the proper proportions, and charge into the puddling-furnace the mixture in the same quantity that would be used for an ordinary charge of pig-iron.

The heat isnow let on, and the changes are so rapid, that within two or three minutes the stirring of the mixture must be begun, to raise the cooler granules from the bottom,-and allow the hot upper granulesto descend, thus hastening the melting down, and keeping the iron and oxide thoroughly intermixed. In the course of fifteen minutes, the iron and ore will be completely fused, both in a highly fluid state, and intimately intermixed.

'lhe boiling next begins, and the stirring of the boiling mass is continued. In about eleven minutes the oxide, or cinder-will drop from the iron, leaving the latter in spongy, pasty lumps, which require turning over frequently for about ten minutes, to complete the decarbonization. v

The iron is now in a state of greater purity, for being formed, into puddle-balls, and withdrawn from the furnace.

This process occupies much less time than the ordinary process of puddling pigs; consequently it saves fuel and labor, which are both expended in proportion to the time occupied in going through with the process. It lessens the wear of the furnace, which is in some degree proportioned to the continuance of the heat. It also saves capital, by giving to the same puddling-furnace a greater capacity in proportion as the time required for operating on a charge is shortened.

It saves waste, as the loss from oxidation of the iron is in some measure proportioned to the duration of the operation. It lessens the risk of losses frominat tention, by lessening the stretch of attention required on the part of the workman; and with all these advantages in the operation of this process, the product is a wrought-iron of greater purity, and higher value, than has heretofore been yielded by puddling.

I have deemed it unnecessary to describe the puddling-furnace, or the manner of operating it, as 1 mm ploy the ordinary furnace in general use in thetrade, and well known to all who are skilled in the manufacture of wrought-iron.

For a similar reason, I have not deemed it necessary to describe the manner in which ore may be reduced into small pieces, by means of rolls, stamps, hammers, and screens, nor the manner in which castiron may be reduced into small pieces, by running it, while in a molten state, upon a rotating centrifugal scatterer, and thence into water, or dropping it directly into water, or casting it in rods, or thin plates, with breaking-creases, and then breaking it up by stamping, or otherwise, as all such methods of dividing, or granulating metals and other materials are well known in the trade.

The operation of reducing the material to a suitable state of division is gieatl y simplified by dispensing with the smallness and uniformity in size of granules, which is almost, if not quite indispensable, in the methods previously proposed for using them in the puddlingfurnace.

What I claim as my invention, isv e The process of puddling iron, by mixing castiron, divided into coarse granules, or pieces, with oxide of iron, melting, stirring, and boiling them together, and balling the iron in a puddling-furnace, substantially as described.

CHAS. HEWITT. Witnesses:

W. O. TAYLOR, GEO. W. VANKIRK.