US1036499A

US1036499A - Metallurgical furnace.

Info

Publication number: US1036499A
Application number: US61140911A
Authority: US
Inventors: Fred B Lamb
Original assignee: ALBERT B FRENIER
Current assignee: ALBERT B FRENIER
Priority date: 1911-02-28
Filing date: 1911-02-28
Publication date: 1912-08-20
Anticipated expiration: 1929-08-20

Description

F. B. LAMB.

METALLURGIAL PURNAGE. APPLIUTION FILBD.PBB.28, 1911, y v 1,036,499, Patented Aug120, 1912.

4 SBIEBTS-SHEET 1.

A` FRED B. LAMB.

T. B. LAMB METALLURGICAL PURNAGE.

P. B. LAMB.

METALLURGICAL URNAGE.

APPLICATION FILED rmm, 1911 1,036,499. Patented Aug.'20, 1912.

4 SHEETS-SHEET 3. y

E. LAMB.

MBTALLURGIGAL FURNACE.

APPLICATION FILED 1313.28, 1911.

1,036,499. Patented Aug. 20, 1912.

4 SHEETS-SHEET 4.

INVENTOR F R E Dl B. LA M B.

'55, refining by reducing sulfur and deoxidiziiig,

UNITED .STATES i PATENT oEEioE.

FRED B. LAMB, or BEr'iENDoRii,v Iowa, AssrGNoR oF ONE-*FOURTH To ALBERT B. ERENIER, l0E DAVENPORT, IOWA.

METALLURGICAL FURNACE.

Specication of Letters Patent.

Patented Aug.- 20, 1912.

App'iicatoii lfiled February 28, 1911. Serial No. 611,409.

To-aZZ whom t may concern: A Be itknown that I, FRED B. LAMB,`a citizen of the United States, residing at Bettendorf, county of Scott, and State .of-Iowa, have invented certain new and useful Improvements in Metallurgical Furnaces, of which the following is a specification.

My invention relates to metallurgical furnaces, substantially in accordance with the requirements of a new process of making steel, as set forth in'an application for Letters Patent of the United States filed by me' the highest gradevof steel with a degree ofv economy heretofore impossible.

Another object of my invention is to greatly reduce the costof maintenance and largely increase the output.

Still another-object of my invention' is to make possible lthe use of electrical'energy as a refining element without increasing the cost of the finished product 'beyond that' resulting from other methods.

These and other objects I accomplish by the improvements hereinafter fully described and. particularly pointed out in the claims.

In the drawings: Figure 1 is a transverse section `of a tilting furnace embodying my improvements Fig. 2 is a similar. view` one-half of the furnace in longitudinal ceni tral section and the other half in side elevation.

The electric furnace, the latest contribu- Ition to the art of steel making,- has proven a disappointment as.v a melter of a cold charge. Its extravagantconsumption of electrical energy (when'produced means other thanwater power) makes its use commercially prohibitive. Butas a means for one vessel to another.

it is unexcelled and has lproven its worth even at a slight increase in cost of finished product.

In the present day practice it is customary to charge the electric furnace (a spefjn cially constructed unit) with hotl metal which had been previously prepared by having been acted upon by an open hearth furnace or converter. Where metal from a blastl furnace is available, itl is generally conveyed tofa mixer and from there conveyed often times long distances to a converter., where it is blown for carbon and silicon and again ladled and conveyed long distances to the electric furnace for refining and finishing. It is 'also the practice to convey hot metal to an open hearth furnace for the elimination of phosphorus and then I conveyed tothe electric furnace for finishing. Again the basic open hearth has been charged with cold metal, where it is melted and phosphorus, carbon and silicon reduced to allowable limits, and then conveyed toran electric furnace for refining.

Ingall these methods, separate mixer, separate open hearth furnaces, separate converters and separate -elect-ric furnaces are employed, i'esulting in the .excessive lossv of initial heat of the metal due to the frequent ladling and conveying long distances and pouring from Much of the time, fuel and expense incident to such procedure is expended in restoring this lost. heat of the metal and its various retainers-an expense seriously effecting the final costof the finished product.

The open hearth furnace is unquestionably the fastest and most economical means known for liquefying a cold charge and vwhen lined basic it is unexcelled for the elimination of phosphorus. The converter, either of the bottom side .or surface blow Vtype excels in the elimination of carbon and silicon. I have therefore designed a furnace in which will be found confined in a single 'unit the tilting open .l hearththe converter and the electric, so

' nally and transversely, and near its ends it dividually. This kind of a furnace -comprises a substantially rectangular body hav# ing a frontwall A, a rear wall B, en d w-alls C, a bottom D and a roof. v-The bot-tomor 5 floor consistsl ofa supportingfmetal retain-v ing sheet a, which, betweenV its parallel upwardly'lianged -sideedges is concaved or dished andprovided with the ordinary silica brick lining b, which,'in turn is coveredwith the material` c' for either an acidr or basic lined bottom. n

The shell -a is reinforced yboth longitudiis provided withcorrespbnding rockers, al.

The curved treads of thesefrockers rest. and

travel upon a seriesof segmentally arranged anti-friction rollers, e, that are journaled at equal distances apart in parallel segmental frames e, 'and V'these rollers rest" and travelI upon concaved. tracks E built upon va suitable foundation. The end walls C of the vfurnace are provided with the usual gas 'or fuel ports F, through'which the gas from the burner H and heatfrom the regenerative chambers (not shown), through the The lower portionof this gate, however, isv

imperforate, and when the gate is raised suficiently it closes the fuel-ports and seals the furnace. Th'ecurved treads of the rockers d, and the concaved tracks E are struck from an axis intersecting the center of the fuel-ports, so that, no 'matt-er inwhat tilted position the furnace may be, the heat prodr ucts will continue to blow into the furnace.

The furnace may be tilted or rolled through the medium of a hydraulic cylinderGrhav? ing a ram or pistonv f which connects with the center of length of oneof the rockers, at a point above its tread. y The front wall,Aof the furnace isprovided with the usualcharging doors. The lower portion, ofthe central charging door opening is formed by thebottom of the furv nace being extended out under this doorway forming the bottom of a pouring spout J, theside edges of which are raised sulii ciently` to confine'the metal when pouring. This charging doorway isopened and closed by a vertically movable gate K, which is operated through the medium of a chain or cable by 'suitable mechanism '(not shown). Opposite the char ingdoor-way, the rear wall of the furnacegis provided with a comparatively small opening 2, which communicate's with a blowing chamber or converter 3' at a point next the bottom thereof, which latter and the oor of said opening are a be used.

continuation ofhthe bottom of the furnace. This blowing chamber or :converter 3ds built out from and removably attached to the rear wall of the furnace. Its outer shell may be of rectangular shape and is made of l sheet metal. It is lined by a course of brick and by an inner lining of the composition usually employed for lining converters. The inner contour of the inner lining is of flask shape with the mouth or opening drawn to one side as shown. This'converter is retained in place against theA rear wall of thefurnace by any suitable means, such as lugs andkey-wedges (not shown). -Its outer lwith a series of openings or twyers 5, communicating with an a1r chest or box 6, that 1s supplied with air under pressure from'an air intake 7. Avertical passage 8 is provided in the rear wall of 'furnace immediately above and separate from opening 2. Its lowerend is projected outward and discharges into the converter through opening provided. If desired a suitable air blast pipe may extend down through' this passage, through which a suitable vblast of air may be blown, or the passage may be suitably prepared for doing vthis. While a bottom blow converter is thus shown and described, it isevident that a side blow or a surface blow type ofV converter could At suitable points two or more large corre spending electrodes 9, 9, extend down through suitable openings in the'roof of the furnace. The upper ends of'these electrodes are suitably secured in the overhanging rear ends of

horizontal arms

10, 10, the forward ends of which are rigidly fastened in the upperends of vertically disposed uprights 12. I 4donot wish to be confined to the construction of the means shown for supporting these electrodes, but whatever means are employed, I prefer them to be such that the'elect-rodes can be adjusted. As shown in the drawings, these uprights 12 extend down between two vertical side members, 21, the lower ends of these side members are suitably secured to U-shaped frames 13, bolted to the front wall of the furnace. The' upper end of these -side members are united vby a suitable cap, and below this cap the upright 12 is sandwiched between the side members.

At a suitable point uprights 12 have a nace knovvnto the art would be commertransverse shaft 1i journaled in bearings 15,

angles thereto and journaled in a frame ,permanently attached to said arm. Shaft 18 l as a suitabley wheel mounted on its front end with which to revolve it, and when this is done, and shaft 14 turned, gears 19 on the ends'thereof engage racks 2() on' the front edges of the parallel side members, raise or lower said varms and the electrodes carriedin the overhanging ends thereof.

While I have thus described a specificmeans of applying electricity to the-melted` metal that can be adjusted or withdrawn from the bath, it is Obvious other means could be adapted-without departing from the spiritof myinvention. Which resides broadly in the use of means which may be properly adjustedl while in use and While othei` agencies are performing their Vparticular function in the reduction of the metal.

The furnace as above described is adapted particularly to the making of the highest grade of steel from raw materials so base and impure that their use inl any other furcially prohibitive.

While the open hearth furnace, of the present day practice, when lined basic, removes'or reduces to within allowable limits,

carbon, silicon, manganese, phosphorus and possibly sulfur, the length of time, and amount of labor, fuel and expense required to make the proper reduction, depends altogether' upon the manner in which the above elements are chemically combined.

' If the cold charge be high in carbon, liquefaction begins promptly, and the'entire mass is melted down quickly, but the attending reduction of the 'carbon to within the allowable limits is accomplished, only after several hours of painstaking labor and the subjection of the bath to the fierce oxidizing action of the fuel.- 4If sulfur is also present further time must be expended and more fuel consumed in what oft times proves a futile attempt to remove it. While it is possible -to bring forth a very satisfactory .grade of steel from the basic .open hearth furnace, the baser the raw materials, the more difficult and more expensive does the operation become and the more damaging to the furnace, due to the long exposure to the fierceaction of the fuel, necessitating morev frequent and expensive repairs vand greatly increased cost of maintenance. V

Confining its use to that which it accomplishes quickest and best, namely, melting and dephosphorizing, leaving the reduction of carbon, siliconv and sulfur to other means, the first step toward lowering cost of productionA is achieved. While the electric furnace has proven itself capablel of producing steel from a coldcharge of cheap .low grade base raw materials, the extravagant consumption of electrical energy is such as to render its use commercially prohibit-ive, but

if its use be confined to desulfurizing and del-oxidizing after the bat-h .has been brought to a most favorable condition by other means, its use actuallybecomes a matter of economy and the second step toward lowering cost of production is taken. As the open hearth excels in mel-ting and dephosphoriz- `ing and the electric furnace in desulfurizing and deoxidizing, so does the converter excel in removing carbon and silicon. My improved furnace combines .these three Well known agencies and their individually superior .functions are so manipulated that the highest grade of steel is brought forth from materials and at a cost heretofore impossible.

The operation of my improved furnace is substantially as follows: After the hearth or melt-ing chamber, which is lined basic, has been raised to the proper temperature, lime stone is charged to form a slag, then 15 ton (presuming the furnace to be of 15 ton capacity) of cheap low grade pig iron, or part )i0 and art steel sera or all cast sera) or cast borings. As the4 carbon content of an all pig charge or of a cast scrap charge would be very high, liquefaction will begin promptly and the entire charge will be melted down in about two hours. lhile a regular open hearth furnace would melt, this high carbon charge just as quickly, the attending reduction of this carbon and silicon to within allowable limits .can only be accomplished at theexpense of much labor and hours of time. Ttis this feature of steel making by the open hearth that creates expense and contributes to the high cost of the finished product. lf metal of lower car-4 bon be charged into anopen hearth furnace,

-such as a half pig and half steel charge, it

will naturally take less time and expense to reduce the carbon to within allowable limits, but this gain will be offset by the increased time taken to melt, sothat what is saved in one direction is lost in another. In order to keep carbon and sulfur low as possible, half select pig and half select steel scrap are usuv ally used in open hearth practice. This is high priced material. A low grade cheap pig iron could be used at a great saving, if its first cost were not offset by the excessive expense incurred in reducing carbon and other injurious elements.

In my improved furnace lthe open hearth department will not be called upon to performthisexpensive part of the process, `but confined solely to melting and dephosphorizing, for, as soon as about 5 tons of melted metal has accumulated in the bath, the blast will be turned into the converting chamber 3 (if it be a bottom blow converter as 40 portion of thecharge at a great saving of shown) and thel furnace tilted toward the Ation of the furnace, an accomplishment im' converter until it is nearly, but not quite, in' the position shown in-'Fig. 2v of the drawings, and the molten metal will iiow through the opening 2 into same. In about ten' minutes this five ton mass-of moltenmetal will be thoroughly decarbonized and desiliconf ized and incidentally its temperature raised from about 1800o F. to about 3000o F. 'Thus the convert-ing department of myA improved furnace accomplishes in a few minutes that which takes hours by the open hearth furnace, and with no other fuel than a blast of air. In addition to this great' saving of time and expense, other most favorable conditions obtan*conditions non-existent in the straight open hearth practice. These are first, al highly acid slag develops during the` act of blowing in the converter. This `is removed by-tilting vthe furnace .farther .in the same direction until the level of the surface of the metal reaches the lip or upper edge of the outer wall of the converter, as-

shown inFig. 2, so as to allowthe slag to drain off. The removal of the slag in this manner may be expedited by directing a blast of air from the mouth ofthe air passage 8 laterally across the surface of the metal. Thus the bath is freed from a large Ina-ss of highly acidulousand impure matter without interrupting the continued acpossible in the regular open heart-h furnace. Second. As the furnace is tilted back to its' normal position, this 5 tons of metal at a temperature ofabout 3000o F. ows back into the melting chamber, intermingling with the bath and materially raising the temperature of the entire mass and greatly hastening the liquefaction `of the unmelted fuel. Third. This metal from the converter being thoroughly impregnated with oxidizing gases, due to the action of the air blown into it, the carbon in the bath will most eagerly combine therewith, acting exactly as Y iron ore does in the ordinary practice, thus eifectinganother saving in avoiding the use of iron ore as an oxidizing agent. Y

As the furnace has'been made to tilt with the gas or fuelports as an axis, the melting op# eration in the melting chamber has not been interrupted during the act of blowing and returning the blown mass to the par- ,ent bath. Dephosphorization, through the action ofthe lime slag has alsovgoneonunlous slag and in a greatly increased temperature of the bath.' This acid slag formed by blowing a small portion ofthe bath in the converting chamber is removed simply to lessen the difficulty that would follow in keeping the lime slag in the melting hearth in the best possible conditionit leaves just that much less to contend-with. Itcould be returned to the hearth, if so desired, without injury to the basiclining owing tothe presence of the lime slag. At the end ofV about two hoursl time the entire charge will be melted, decarb'onized, desiliconized, dephosphorized and brought to a very high temperature. n i

' If thesulfur content could be disregarded in buying raw materials' for use in'iconnection with open hearth practice, much could be savedboth in the purchase price of the material and in decreased loss of the finished product. While sulfur can possibly be eliminated or a't least much reduced in the openl hearth furnace, it is accomplished, if at all, only at the expense of much time, fuel, and expensive alloys, and the vdevelopment of the steel makers vworst foe, viz. occluded gases, caused by the continued exposure of the bath to the fierce oxidizinginfiuence of the fuel. As the electric Vfurnace operates under nonoxidizing influences', it excels inthe removal of sulfur and in deoxidizing, in fact it is the only really successful" means known. It has been found. in ordinary practice, whenv hot metal to be relined is served an. electric furnace from the open hearth orl converter,

by far the greater per cent. of electrical'energy is consumed in bringing the slagymetal and furnace to the proper high temperature, therefore if the metal, slag and furnace were brought to this necessary high temperature before the electric current `was applied, the

most economincal conditions possible wouldv follow. Thus, when the bath has been properly decarbonized, desiliconized, `dephos.

,phorized and broughtY to al high `temperature by my improved'furnace in the manner heretofore described, thegates I are raised closing the gas'ports, practically sealing the furnace. Then the electrodes are lowered into position 'and the current applied to the bath for about one'hour, resulting in a bath of the highest grade of steel obtainable, made from low grade Vmaterials without regard to' chemical content. The furnace is then tilted in the' direction shown in Fig. 2

ofthe' drawings, and the contents vdrawn olf through 'the pouring spout J into a ladle ready for teeming. I do not confine myself to the production of steel from a cold charge, as hot or meltedmetal from the blast furnace, cupola or mixer can be introduced into the melting chamber of my furnace and the most satisfactory and economical results follow. Again as a very good grade of steel couldbe made without the aid of the electric current, I desire to 'be understood as claiming as my invention, the furnace as hereinbefore described, either with or without the electrical features described.

that I claim as new is l. A metallurgical furnace comprising a melting chamber provided with gas or oil fuel melting means, a. blowing chamber having communication with the melting chamber, and adjustable electrodes extending into said melting chamber.

- 2. A metallurgical furnace .having an open hearth provided with fuel port-s and communication with regenerative chamber,

a blowing chamber communicating with the hearth, and adjustable electrodes extending into said hearth.

3. A metallurgicalvfurnace of the open hearth typeadaptedto be tilted and comprising a melting chamber, and a blowing chamber comi'nunicating with the melting chamber, and adjustable electrodes 'extending into said melting' chamber.

4. A metallurgical furnace of the open hearth type adapted to be tilted, comprising a melting chamber, a blowing chamber,

vfuel ports, and regenerating chamber flues having communication with the melting chamber, adjustable electrodes 'extending into said meltingl chamber, and means adapted to maintain operative communication between the melting chamber, the

blowing chamber, fuel ports, and the re.

generating chamber flues and the electrodes, whether the furnace is in a normal position,

, a tilted position, orduring the period of being tilted.

5. A metalhirgical furnace having. an open hearth adapted to betilted and vprovided with fuel ports and communication with regenerative chambers, and a. blowing 'chamber communicating with the hearth and adjustable electrodes extending into said hearth, and means .adapted to maintain operative communication between the hearth and the blowing chamber, the

-- fuel ports,the regenerative chamber liues and the electrodes, whether the furnace is in a normal position, a tilted positi ing the period of being tilted.

6. A metallurgical furnace of the open hearth type comprisin a melting chamber n, or durprovided with means or electrically treating its contents, and a blowing chambpr communicating with the melting chamber.

7. A metallurgical furnace of the open hearth typeadapted to be tilted and comprising a melting chamber provided with lmeans for electrically treating its contents and a Lblowing chamber communicatin with the melting chamber.

8. A metallurgical furnace comprising a heart-h provided with fuel ports, communication with regenerating chambers, also means for electrically treating the contents of the hearth, and a blowing chamber communicating with the hearth.

9. A metallurgical furnace of the open hearth type adapted to be tilted, comprism a meltingv chamber having a blowing chamber, fuel ports and regenerating chamber fluesr ,communicating therewith; and means for electrically treating the contents of thel melting chainber,.and means adapted to maintain operative communication between-the melting chamber, thev blowing chamber, fuel ports and the regenerative chamber flues whether the furnace'is in a normal position, a tilted osition, or during the period of being tilted? 10. A metallurgical furnace having a hearth adapted to be'tilted and provided.

with fuelv ports, communication with regencrating chambers, a blowing .chamber communicating with the hearth, and means 'for electrically treating the contents of the hearth, and means adapted to maintain op- Aei'ative communication lbetween the heart the blowing chamber, the fuel ports and the regenerating chamber ilues whether the furnace is in a normal position, a tilted 0- sition, or during the period of being tilte l 11. A metallurgical furnace comprising a hearth, a blowing chamber communicating with said hearth, fuel and air ports communicating with said hearth, means adapted to close' communication between the hearth andsaid fuel ports, means for tiltingv the vfurnace about the fuel ports as an axis and' means for electrically treating the contents of the hearth.

12. A metallurgical furnace comprising a hearth, a blowing chamber having communication with the hearth and provided with an air blast slag removing means, means for tilting the furnace, and means for electrically treating the contents ofthe heart-h.

13. AA metallurgical furnace comprisinga hearth, a converter v removably attached thereto and which-in itstlower part communicates therewith, andifmeans for electrically treating the contents'of-the hearth.

14. A metallurgical furnace ,comprisingaf hearth, a blowing chamber removably attached thereto and which in its lowerpart vcommunicates therewith, means for elect-rispout located inthe opposite sidewall, end

. walls provided with Juel and airports communica-ting with the hearth, means for tilting the furnace about'the fuel ports as an axis, and means for velectrically treating the contents of the hearth;

17 A metallurgical furnace comprising an open hearth, a removable blowingrchamber 'attached to one of the side walls and having communication with the hearth.l charging doors and pouring spout located in the opposite side wall, 'end walls provided with fuel ports communicating with the hearth, means adapted to close communication between` the hearth and said-fuel ports, means for tilting the furnace about the fuel ports as an axis, and meansl for electrically. treating the contents of' the hearth. n

lnay/hand this 25th day hearth type, comprising a melting chamber,

a-,blowingv chamber attached to one of the lside wallsvand having` communication with the hearth, air blast slag removing means in said Wall, vcharging doors and pouring spout located in the opposite sidewall, end walls provided with fuel ports communieating with the hearth, means adapted to close communication between the hearth and said'fuel ports, means for tilting the furf nace about `-the fuel'ports as an axis, and means for electrically treating the contents ofthe hearthf v ,In witness whereof I-have hereunto set of February 1911. v FRED lLAMB.

' Witnesses:

Y A. B; FRENIER, F. M. GoDDARD.