US691297A - Open-hearth steel process. - Google Patents

Description

' (No Model.)

(Application filed Feb. 12, 1901.

' 2 Sheets-Sheet I.

4 Witnesses.

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No. 691,297. Patented Jan. 14, I902.

J. L. SMITH & R. BEDFORD, In.

OPEN HEARTH STEEL PROCESS.

(Application filed Feb. 12, 1901.

(No Model.) 7 2 Sheets-Sheat 2.

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UNITED STATES PATENT OFFI E.

JOHN LAwsM TH AND ROBERT BEDFORD,AJR., OF EAGLESCLIFFE, ENGLAND, ASSIGNORS OF ONE-THIRD TO THE SOUTH DURHAM STEEL ANDIRON COMPANY, LIMITED, or STOCKTON-ON-TEES, ENGLAND.

OPEN-HEARTH STEEL Paocss s.

SPECIFICATION forming part of Letters Patent No. 691,297 dated January 14, 1902. I V I Application filed February 12, 1901. Serial No. 47,067. (No specimens.) i

To all whom it may 1: ten steel, but 'wealso charge into the empty or Be it known that we, JOHN LAW SMITH and practically empty compartment any desired ROBERT BEDFORD, Jr. subjects of the King'of quantity of solid materials-such as pig-iron, Great Britain and Ireland, residing at Eaglesscrap metal,or other suitable material-where A 5 cliEe,-in the county of Durham,England, have such chargeis exposed tothe heat ofthe furinvented certain new and useful Improvenace and raised toasuitable temperature bements in Open-Hearth Steel Processes; and fore coming into contact with the-molten steel we do hereby declare the following to be a full, which is pooled in the larger compartment, it

clear, and exact description of the invention, beingunderstood that by unpuritied metal 10 such as will enable others skilled in the art we refer to such metal as would run from a to which it appertains to make and use the blast-furnace, cnpola, orother sourceinaconsame. dition requiring further treatment'for conver- This invention consists in a novel or imsion into steel of the gradeto be produced by proved process for producing steel in an or the process in question.

I5 dinary type of open-hearth furnace adapted I Our processisacontinuous one,and the steel for the purpose by being provided with one or is never drawn from the larger compartment more dams so arranged that the hearth is di-- until it is desired to shut down the furnace; vided into two or more compartments up to but steel is from time to time drawn from the any required height and above which the said smaller compartment, this drawing off new 20 compartments merge into one large chamber all emptying the smaller compartment comwhich is common to all, whereby a charge of pletely. steel can be withdrawn from one or more com- In the accompanying drawings, which reppartments from time and time, while abath resent an apparatus for carrying out our imof molten purified steel is left in one or more proved process, Figure 1 is a longitudinal 25 of the other compartments to remain on the section of an open-hearth furnace. Fig. 2 is furnace-bottom after tapping. a longitudinal section of the hearth, and Fig.

Before proceeding more particularly to de- 3 is a cross-section of the same. scribe the nature of our said invention we Referring to Fig-1, we propose to divide would first remark that it is a recognized adthe hearth a into separate .compartments by 3o vantage to retain on the bottom of an openhaving an elevated portion 12 in the lining. 8o hearth furnace a bath or pool of steel leftover This elevated portion 12 is made of similar from previous tappings, into which fresh material to the hearth itself, and this'portion charges of molten metal in an unpurified or partition -wall may be of any desired state-such as would be drawn from a blastheight, each compartment being furnished 35 furnace, cupola, converter, or other suitable with its own tap-hole c at the bottom. In

source of supply-can be poured from time order to control the flow of the slag, which is to time without undue injury to the furnaceliable to take place from the larger compartbottom; but the dilficulty has been to'eifect ment into the smaller compartment as the this resultina practical manner, and the only latter is being emptied, we provide one or 40 methods hithertodevised which have been more channels f in the elevated portions b, commercially used haveheen by tilting the transversely thereto. These channels may furnace bodily or by other awkward means he of any desired width, depth, and shape. until a desired quantity of steel has run out. This construction allows the metal to flow By such processes, if solid material is also to from the larger compartment into the smaller 45 be used it must be charged into thebath of compartment without disturbing the slag, molten steel, which is cooled thereby and the which is allowed to settle in the manner reprocess correspondingly retarded. quiredto protect and clear the steel. If the By our invention we not only charge the charge is large enough, one continuous bath large compartment. with unpnrified molten will be formed, as shown by the line 03. When 50 metal, which is,receieved into a bath of molthe level of the steel is reduced to the line 3 I00 two separate baths a. and a will be formed.

or air-boxes e for cooling the hearth. If desired, an additional water-bosh or air-box may be placed under the bank or wall 11 for cooling purposes. I 1

While we have shown a furnace as divided into two compartments, it is obvious that we may use any number of these compartments and that they may be of any desired size and shape. In practice, the furnace being arranged.

,anddesigned with two or more com partments,

as described, but preferably with a larger and smaller compartment onlyfor convenience of description, it is intended that the following process should take place: The larger compartment being charged with a bath of molten steel left over from the previous tapping while the steel from the smaller compartment was run completely 0E, the process consists in charging'on the empty part of the furnace -'hearth--i. e.,the aforesaidsmaller compartment -after fettling, (if necessary,) a quantity of ore or other oxids of ironsuch as mill-scale, tap-cinder, and, if desirable, a .certain quantity of limestone and scrap or other suitable materials, as circumstances and experience demands. This charg ing of solid matter into the smallempty compartment protects the hearth .in this compartment from the overflow of molten" metal from the large compartment, which overflow is'not allowed to take place until the solid material in the smaller compartment begins to 'inelt. As soon as the scrap, ore, and the like has been brought up to a sweating heat .molten metal from the blast furnace, converter, mixer, cupola, or the like is run'into that compartment of the hearth containing molten steel from the previous charge, and to which, if preferred, has been added oxid of iron, the whole mixing together and then flowing over the dam into the other compartment, coming in contact with the oxids of iron and scrap or the like, which are now at the best possible heat for making a chemical union. This submersion of the solid material in a molten bath causes a boil, after which the charge in both compartments is worked in the usual way by fresh additions of iron ore and lime until the requisite purification and reduction of carbon has been effected. v

When working scrap, less depth of bath is required and less impurities are, found. The slag covering the metal in a thinner sheet also permits the flame to act with greater intensity upon the metal.

The advantages are acontinuous process giving regular supplies to the mills at small intervals, a ready means of using the surplus scrap to advantage, increased output, and reduced wages and coal consumption. 7

Having thus described our invention, what we claim, and desire to secure by Letters Pat'- ent of the United States, is-

The continuou's'process of manufacturing steel, which consists in preparing a bath of molten steel in an open-hearth furnace provided with compartments, drawing off from time to time steel from .one of said compart

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