US906757A - Process of manufacturing steel. - Google Patents

Description

PATENT OFFICE.

WILLIAM R. WALKER, OF CHICAGO, ILLINOIS.

rnocnss or MANUFACTURING STEEL.

Specification of Letters Patent.

Patented Dec. 15, 1908.

Application filed December 1, 1894. Serial No. 530,582.

To all whom it may concern:

Be it knownthat I, WILLIAM R. WALKER,

of Chicago, Illinois, have invented certain new and useful Improvements in the Processes of Manufacturing Steel; and I do declare the following to be a full, clear, and exact description of my invention, suflicient to enable others skilled in the art to which my invention pertains to practice the same.

In the manufacture of steel by the Bessemer and open hearth processes it is customary at the close of the refining \operation by which the impurities are removed from the metal, to add to the more or less completely decarbonized-and purified metal within the converter or refining chamber, a quantity of metallic alloy, the purpose of which is pri-' marily to recarh urize the refined metal and as well also to serve as a vehicle for such the Bessemer process as now commonly agents (as manganese, silicon, aluminum or the like) as shall impart to the steel the desired character or qualities resulting from the use of such agents. Thus,,for example, in

racticed it is customary to add, at the en (if the blow, to the more or less decarbonized molten metal within the converter a quantity of spiegel containing sufficient carbon and manganese to supply the desired percentages of these agents to the converter char e, and containing sufiicient silicon to supp ement any deficiency that may exist in the silicon content.

The method at present generally practiced for the production of spiegel consists in charg- Eg a smelting furnace with a hly mangaerous ore and from time to tune the furnace is tapped and the metal run out into ilgs, as in ordinar blast furnaceoperation.

e foun to varyto a considerable extent especially in their manganese content throughout the-furnace casts, and this variation sometimes occurs not only in different casts from the same furnace but in pigs formed from difierent portions of the same cast. Hence, it. is customary to sort the pigs of spiegel, more especially with reference to their man ganese content, and these pigs are afterwards charged into a cupola together with suitable quantities of ig-iron necessary to give to the cupola pro not the required per centages of carbon, manganese and silicon.

This common method of roducing spiegel is very expensive not only cause of thecost to the labor of casting the spiegel pigs of spiege thus produced are often I into igs, transporting and handling the pigs and t e cost incident tore-melting the metal in' a on ola, but it is found that a most serious an wasteful loss of manganese occurs by reason of itsoxidation in the cupola. A further objection to this common method of producin spiegel is that it is frequently de sired to c ange the grade or character of the spiegel to be used as a re-carburizing additlon in the Bessemer converter or open hearth furnace upon very short notice, at a change in the character of the s iegel elivered from a cupola cannot be e ected with certainty inside of several hours. With this common method of roducing spiegel it is obvious also that in t e re-melting of the pigs of spiegel within the cupola, the addition of pig-iron therein reduces to a material extent the manganese content of the s iegel. Hence it is that, in order to obtain 'rom the blast furnace pigs of spiegel sufliciently high in manganese to permit of re-melting with pig; iron in a cupola, it is necessary to use hig grade manganiferous ores, which, being found only in certain localities, are comparatively scarce and expensive. On the other hand, a lower grade of manganiferous ores, suitable for producing a lower rade of spiegel can be obtained m many loca ities and atcomparatively much less cost.

My present invention has for its object (so far as 1t relates particularly to the production of spiegel), to provide a process whereby a spiegel having especially 1ts manganese and as well also its carbon and silicon contents more thoroughly and more uniformly distributed therethrough can be obtained without the necessity of remelting the s iegel within a cupola, and has for its object a so to provide a process that will enable spiegel, suitable as a recarburizing addition to the char e of a Bessemer converter or like refining 0 amber, to be'produced from low rade and inexpensive ores, such as are to be ound ducings iegel, it will be found applicable also to t e production of other metallic alloys suitable as additions to the charges of a Bessemer converter or open hearth furnace,

-the recise character of which alloys will de- 11 upon the particular agents for the devery of which to the converter or refining chamber the said addition serves as a vehicle.

My invention will first be described in connection with the production of spiegel and the application of the invention to the production of other metallic alloys suitable" as converter additions will thereafter be more fully pointed out. In the preferred and most economic practice of my invention the smelting furnace will be charged in usual or suitable manner with a low grade manganiferous ore, such, for example, as will give to the product of the smelter a manganese content of say from 8 to 12 er cent. The metal from the smelter will e delivered by a suitable runner into ladles and by (preference will be transported by these a es to a suitable mixing chamber having a capacity sufficient to receive one or preferably several casts from the spiegel furnace. This mixing chamber may be of the character commonly employed at those plants at which the direct process of steelmaking is practiced and in which the casts from various blast-furnaces producing pigiron are delivered into 'a common mixing chamber in order to give a more uniform character to the converter charges. As the low grade spiegel is thus delivered from the smelting furnace I gradually add to the metal while in the runner or at the discharge end of the runner or while in the receiving ladle, a quantity of richer spiegel, or ferrO-manganese, (and if desired, also ferro-silicon or-similar iron alloys) necessary to raise the manganese content and as well also the silicon and carbon or the likelof the low grade spiei comminute gelto the required percentages. These adtions of richer spiegel or ferro-manganese or the like may be made in molten condition, although I refer to make such additions in I or lump form, the richer spiegel or ferro-mangianese being broken to about the suc of bio ory nuts and brought to a redheat and then gradually delivered into the mass of metal from the blast furnace. I prefer to make these additions while the metal from the blast furnace is passing down the runner since thereby a more gradual and uniform distribution of the additions can be eflected and the intimacy of the mixture can be increased by the a itation incident to the gassage of the metal own the runner and its elivery into the receivin ladle. The charge of metal within the la e may then be delivered to the mixingchamber (if a chamber be em loyed). and there mixed with pre-del-ivered c arges, and from this mixin chamber portions of the metal will be tappe from time to time for additions to thecharges 4 chamof the Bessemer converter or re her By thus adding therichersp1egel or ferro-manganeseor the like tothe low grade before the delivery of the metal to the chamber I insure a far more'lintimate-mix ture of the additions with the mass of metal than would be possible ifthe additions of of metal to suc I were made in the mixing chamber, and con-" sequently a much more uniform distribution of the manganese, silicon and carbon orthe like throughout all arts of the mass of metal within the mixing 0 amber is obtained. The thorough mixture of the additionsof richer s iegel or ferro-manganese or the like with the blast-furnace casts results not merely from the mechanical agitation of the smelted metal and the additions made thereto during the delivery into and discharge from the receiving ladle but the agitation of the metal within the ladle incident to the generation of the gases therein during the time that the metal is within the ladle also contributes .materially to the more uniform mixture of the content of manganese, silicon and carbon, or the like throu hout the entire mass.

When a ric er spiegel or ferro-mangane'se is added to a lower grade spiegel it has been found that there is a tendency of'the metal to stratify, but by making the additions to the low grade spiegel before it is discharged from the receiving-ladle (and preferably before its delivery thereinto) all dan er of this stratifyin of'the metal is avoide la e that receives the charge of spiegel from the smelter will be covered and will be provided with a gas or oil burner or may have an addition of charcoal, or coke dust in order to keep the metal hot in transit from the blast furnace to the mixing chamber (when a mixingchamber is used), and in order'to secure a more intimate mixture within the ladle, I prefer to insert a bar of wood into the molten metal contained therein, the result being a violent ebullition of the mass. When the smelted spiegel from the blast furnace is delivered to the mixing chamber a further intimacy'of the mixture is secured by reason of v the mechanical agitation incident to the dis-' charge of the metal from the receiving ladle into the mixing chamber and the agitation therein result' from the repeated a ditions ii chamber.

That feature of my sists in deliverin to t e metal from a smelter while such meta is running will adapt such metal as a recarburizing addition to a converter charge W111 be found of advantage not merely in the production'of s iegel from lovvWgrade ores in manner herein escribed bu't 1 be found applicable also in other connections in which it is desired to change the character or grade of the recarburizmg metal from the smelting furnace. Therefore, I do not wish this feature of my invention to be understood as restricted either to the production. of spiegel or to the enrichment 0 a low grade s iegel, since so far as the broad feature of ma g the desired additions to the nace before it'is charged from the receivricher spiegel or ferro-manganeseor the'like ladle, "can be practiced with advantage Preferably theinvention. which con-- into the ladle or while contained in the ladle such additions as- (pigoduct of a'smelting fur- 1 \the same relates to the addition of richerspiegel or ferromanganese to alow rade s iegel in manner above defined, I pre er to m ke the required additions at a redheat since the necessity of melting spiegel or ferromanganese in acupola or furnace for this pugpose is thereby avoided, this use of solid ad tions being rendered possible by reason of the uniform distribution of the additions throughout the mass owing to the additions being made prior to the discharge of the metal from the ladles. i 1 Instead of transporting the s iegel from a blast-furnace to a mixin cham er by small ladles as above describe the mixing chamber might be dispensed withv and a single ladle employed of suitable construction and capacity to receive the entirecast from the smelting.v furnace or to receive several successive casts therefrom. Or, without departing from the spirit .of the invention the metal from the smelting furnace having re ceived suitable additions of richer spiegel or ferro-manganese or the like, necessary to adapt the metal for use as a recarburizing ad- I 'dition tothe charge of a Bessemer converter or open hearth furnace, might be transferred directly from the smelting furnace to the l converter or open hearth furnace.

It is manifest that the precise quantity and character of the additions of richer spiegel,

ferro-manganeseor' the like that shouldbe' made to the metal'from the smeltin furnace o will depend uponithe. character of t e metal at such time and upon-the percentages of silicon, man anese, carbon and the like that are i called for y the character or grade of the fin-' ish'ed product of the converter or open hearth v furnace. And it is obvious that changes in the recise grade and character of the spiegel to e delivered to the converter or open hearth-furnace can be quickly varied by variation'in the quantity or character in the additions made to the metal from the smelting furnace.

While my invention is primarily designed for the production of .a spie e1 in mannerabove defined, it is-manifest t at features of 5'5 the invention may be employed in the pro-I duction of other metallic allo s suitable as additions to the charges of the essemerconverter or o tice of my. invention, to obtain the desiredgrade or c aracterfpfispiegel, (or like metallie alloy) before its delivery into the mixing en hearth furnace, and it is plain also that eatures of the invention may be" chamber (ifsuch chamber be used), it ma at times be found that for certain heats a su den change in the carbon content of the con-- verter. product is desired. When such a change 1s desired the spiegel will be delivered to the converter in manner above defined,

and at the end of the blow a suitable quantity of'powdered charcoal, coke, dust or like carbonaceous material will be' added to the metal delivered from the converter afterv the blow. In this way' the required change of carbon content can be madewithout the necessity of changin the grade or character of the entire mass 0 metal within the mixing chamber. So also, if it be desired, say for certain heats of the converter, to vary both the silicon and carbon contents of the spiegel, a uantity of the spiegel may be carriedin a laiile from the spiegel mixing chamber or from the blast furnace direct, and into this ladle a suitable addition of molten ig-iron can be delivered from a mixing cham er containing pig-iron, or from a cupola or blastfurnace in order to give the reqpired silicon percentage to the mass within t e ladle, and after this ladle charge of modified spiegel has been delivered to the converter, the requisite amount of charcoal, coke dust or like carbonaceous material can be added to bring the carbon content of the converter product to the required percentage.

I do not wish to be understood as claiming asjof invention broadly the discovery that spie el from the smelting furnace may be use without re-melting as a recarburizing addition to the charge of a Bessemer con verter or open hearth furnace, nor as claiming broadly the process of producing spiegel suitable as such recarburizing addition by changing the grade or character ofthe spiegel by the addition of molten metal containing agents adapted to impart the desired grade or character to the spiegel, as such-matters are the inventions of others.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent is 1. That im rovement in the process of producing stee that consists in running the smelted metal, that is to be used as a recarburizing addition to the charge of a Bessemer converter or steel refining chamber, from the blast furnace directly into a receiving ladle, mixing with the smelted metal after its discharge from theblast furnace and before its admission 'to said receiving ladle suitable metallic additions of one or more agents for which said blast furnace product serves as a vehicle, refining the body of metal to which said recarburizing addition is to be made, and thereafter while said metallic alloy isstill in the molten condition in which it is received from the blast furnace, adding saidalloy to the charge,.-of a Bessemer coiiverteror steelrefining chamber after the refining operation.

steel :manufa'cture that consists in char percentage below that desired in the spiegel' that is to be charged into the Bessemer converter or open hearth furnace, afterwards tapping the smelted metal from the blast furnace and with said metal after it is discharged from the blast furnace, a metallic addition containing a suflicient excess of ;manganese to adapt thespiegel :as a recarburizing-addition to the charge of a Bessemer converter or open hearth furnace and Lfinally vadding said splegel to the charge of a Bessemer'converter or steel refining chamber.

'3. That improvement in the process of steel -manufacture that consists in charging the blast furnace from whichspiegel is to be produced with ore so low inmanganese as to glvezto-the pro duct ofthe furnace amanganese percentage below that desired in the .spiegel that is to abe chargedinto the Bessemer con- Werter or .open hearth furnace, afterwards tapping the smelted metallfrom the blast-furnace and mixing with said metal afterit is 19mins?! discharged from the blast furnace and before it is removed from the receiving ladle a me- 'tallic addition containing an excess of manganese and finally addingsaid spiegel to the char e of a Bessemer converter or steel refining ('3 amber.

4. That improvement in the process of steel manufacture that consists in charging a blast furnace from which spiegel is to vbe produced with ore solowin manganese. as to give to the product of the furnace a manganese percentage below that desired in the spiegel that is .to'be charged into'the Be'ssemerconver-ter 011; open hearth furnace, afterwards tapping t e mixing with said metal after it is discharged from the blast furnace and before it is removed from the receiving ladle a metallic addition containing an excess of man anese chamber. v

R. WALKER.

Witnesses:

Geo. P. FIsHER, Jr, GED. P. FISHER,

smeltedmetal from the :blast furnace-and v and finally successively delivering the c arges of the metal from the ladle into the mixlng