US2302999A - Method of and apparatus for introducing addition ingredients into molten metals - Google Patents

Description

1942. W.A.O BR|EN METHOD OF AND APPARATUS FOR 2,302,999 rumonucxm amino INGREDIENTS INTO MOLTEN METALS Filed Feb.

Nov.

OPP/Ely INVENTOR W W m I MM BY JWA Patented Nov. 24, 1942 Mn'rnon or AND APPARATUS Fort m'rao-, nucme ADDITION measnmu'rs m'ro MOLTEN METALS William A. OBrien, Fostorla; Oh'io Application February 3, 1941, Serial No. 377,118

. I 7 Claims. This invention relates to a method of and an apparatus for adding ingredients to molten metals to control the physical and/or acteristics of a metal.

In the prior art, the general method of mixing addition ingredients to molten metals, as for example, steel, has involved the addition of the materials while the molten metal was in an open ladle, and thereafter by mechanical means the molten metal was stirred or agitated until it appeared that the additionmaterial had been thoroughly disssolved and a homogeneous mixture chemical charhad been obtained. This method of adding in- 4 gredients to molten metals was subject to many.

difliculties which tended somewhat to destroy the usefulness of the resulting metal, particularly in that the mixtures were not uniform.

- A serious disadvantage of the old method is that the molten metal in the open ladle during the mixing'period was subject to cooling, this being particularly true during the stirring period and in some cases a period of time was necessary to allow the added ingredients to -dissolve 1n the metal before pouring into molds, which further aggravated the situation. In order to overcome this difllculty, the temperature of the molten metal was made inordinately high so that the cooling of the metal would stillleave the temperature remain sufllciently high to allow pouring. If the metal is heated to the high temperature necessary to overcome this disadvantage, there is a tendency for the addition ingredients to become oxidized or otherwise destroyed and, inasmuch as this destruction could not be accurately gauged, it was substantially im possible to control accurately the amount of additicn materials that would be finally included in the metals as poured into molds.

Furthermore, the fact that the addition materials in the old method had to be introduced into the molten metal from the uppersurface, it was extremely 'difllcult to dissolve the materials and it often happened that a large .per-

centage of the addition material floated to the """surface of the molten inetalsand was not dissolved. While the addition materials floated on the surface, subject to the high temperatures of the melt, they were often oxidized by made incapable of being.disso lved.

Y Another disadvantage with this method of disthe air and solving addition ingredients into a melt was that there was no assurance that they would be uniformly disbursed'through the body of the molten metal in the ladle, .with the result that the "pour would not be homogeneous and gave non-uniform results'in that some of the metal would contain a larger percentage of the addition ingredients. The 'present invention provides a method of and anapparatus for the introduction of ingredients into molten metals for the purpose of forming alloys, deoxidizlng or desulphurizing the metal, or the addition of any-material which is desirable to control the physical and/or chemical characteristics of a metal. At the same time, the invention obviatesthe difficulties pointed out in the previous paragraphs in that it provides a method of adding ingredients to molten metals which introduces the ingredients in an easily-controlled, definite, accurate, and

tained in the treated metals.

A means is provided by this invention to convey molten metal from a cupola furnace to a pouring ladle so designed that the ingredients to be added to the molten metal are placed in contact with'the molten metal in the conveying means whereby. the ingredients will besubstantially dissolved in the molten metal before en tering the ladle. The conveyor is so designed that the ingredients are placed in contact with the molten metal in such a manner that the ingredients will be completely surrounded and submerged in the molten metal to be reacted upon by the high temperatures to assure that all 0 the addition ingredients intended to be added to per unit volume of the molten metal will be completely dissolved therein to assure uniform mixtures in the ladle.

To do this a turbulence is caused in the flow of the molten metal through the conveyor means by ballies which tend to reverse the direction of folding over of the metal upon itself so as to cover any non-included inflow and cause a 'gre'dients which may be floating-upon the sur- 4 face of the molten metal. At the distal end of the conveying means immediately above or ad jacent the ladle an enclosure is provided having a vent in its bottom immediately above the ladle so that the molten metal will tend to collect in the enclosure and cause a rotating or swirling action which centers in the vent throughwhich the molten metal flowsinto the ladle. All non-included ingredients which are still iloating upon the surfaces of the molten metal inthe-swirl will be drawn into the core of the stream of molten metal and discharged through the vent so as to assure that the ingredients will be subjected to the high temperature of the molten metal and carried to the bottom of the metal in the ladle by the downwardly flowing stream emcient way so that uniform result! can be obical characteristic of a metal.

It is a further object of this invention to provide a method for the introduction of various ingredients to molten metals, such as, alloys, deoxidizing and desulphurizing agents, which will facilitate maximum inclusion of the ingredient into the molten metal to thereby assure accurate control and uniform results.

It is a further object of this invention to provide a method and an apparatus for its application for introducing various ingredients into molten metal; a method which is very flexible in operation and can be readily controlled to include into the metals any desirable percentage of the ingredients and assure maximum inclusion under all circumstances to obtain uniform results.

Other objects and advantages of this invention relating to the arrangement, operation and function of the related elements ofthe structure, to various details of construction, to combinations 2,302,999 a of molten metal discharging from the vent. This metal will flow from the furnace through the trough-like portion A under the influence of gravity. The speed of flow of the metal canbe controlled by either the size of the opening in the inlet [0A or by the slope of the conveyor id, or both.

The trough Ida is made tortuous by providing baiiies B, I and HD on its-inner side sur- -faces which are positioned in staggered relation and tend to narrow the stream of the molten metal and to cause it to flow in a turbulent manner so as to throw back on itself and turn over as it comes in contact with each of the baflles as is shown clearly by the light flow lines of Figure 2. Adjacent the distal end of the conveyor i4, near the stirrup l8, a substantially circular enclosure- HE is provided, Whose sides may be slightly convergent and whose floor 20 is provided with a vent or aperture 2| so aligned as to be substantially vertical over a ladle 22 which is positioned immediately below it during the pouring operation to catch the molten metal discharging from the vent. The molten metal flowing in the trough A of the conveyor means I enters the enclosure [4E adjacent one side thereof so that as the metal flows into the enclosure NE a rotation is obtained which causes a swirl centering over the vent 2| whereby the molten metal discharges from the center of the swirl to fall into the open ladle 22.

Adjacent the upper end of the conveyor 14 and near the inlet [0A, a means is provided for introducing into the stream of molten metal, flowing in the trough HA, various ingredients which are of parts and to economies of manufacture, will' 85 to be introduced into the metal for controlling be apparent to those skilled in the art upon consideration of the following description and appended claims, reference being had to the accompanying drawing forming a part of this specification wherein like reference characters dcsignate corresponding parts in the several views.

Figure 1 is an elevational view of the invention when combined in operative position witha cupola furnace.

Figure 2 is a plan view of the conveyor.

Figure 3 is a cross-sectional view.

Referring to the drawing, particularly to Figure 1, the general organization of the appa-' ratus for introducing various ingredients to molten metals 'is shown. 'A cupola furnace I0 is erally disposed platform 12 for an attendant. The cupola furnace is of the usual type having an air duct [3 adjacent its tuyres. duct [3 a molten metal conveyor means i4 is provided which is held in cooperative relation with the furnace l0 along a radial line by means of a hinge contrivance l5'which allows the conveyor provided having a supporting base II and a lat- I Below the air the physical and/or chemical characteristics thereof. In order to introduce the ingredients into the molten metal, it is preferable to completely surround them as quickly as possible with the molten metal to assure maximum inclusion or dissolving of the ingredient in the molten metal. It is preferable to introduce these materials as near as possible to the outlet of the cupola furnace allowing at thevsame time sufiicient space so that an operator'can control the inlet "A by means of a plug of soft refractory material 23 on the end of a rod 24.

The floor of the trough IA of the conveyor is provided with an elongated slot 25 paralleling the flow of the molten metal having its greatest depth at a central position and gradually from this point in either direction approaching the surface of the trough A. This provides a nar- Hi to be raised and lowered at its distal end by means of a turnbuckle l6, one end of which is anchored to a fixed overhead portion 81 and the other end being attached to a stirrup l8 fixedly attached to the conveyor by means of a trans- Y verse pin |9.

The conveyor means ll closely cooperates with the outlet vent of the cupola furnace (Figure 3) adjacent its inner end and extends radially therefrom. At the point of cooperation between the furnace and conveyor means, an inlet IOA- is provided which issues into a trough-like portion A of the conveyor so that the molten metal will flow along the'floor of the trough MA. Inasmuch as the conveyor I4 is adjusted so that the distal and adjacent the stirrup i8 is lower than the inlet IOA at the cupola, the molten row groove through which a portion of the molten metal flows in its path down the conveyor I4. Immediately above the elongated slot 25, and, preferably at its central position, a refractory tube 26 is provided having an aperture IiA whose lower end rests upon the floor of the trough A by bridging the elongated slot 25. The leeward side of the refractory tube is cut away at 21 so that the molten metal which flows through the trough I A divides its stream and flows on either side of the tube 26 and is then thrown back from the side walls of the trough A to fall upon the molten metal fiowing'through the slot 25 underneath the end of the tube 26. The cut away ontheend'of tamping r0112 M u opening'andthereby stop th egiietvfoi 'rhciten f metaL when itisdesired" to" irijbp'ehfthe tory material 23 which" tion ed; in1theinlet fl A1? v. 1" efo e vetb k' the metal issuing'irom cha c istics in poured intothei'n V ff; armer w ll which-bridges the top side of the trough MA.

' Adjacent the upper end of the refractory tube 26 a funnel means 28 is provided which cooperates with the center aperture 26A of the tube and provides a ready means for introducing the ingredients into the tube so that they may flow therethrough and issue into the slot 25 in the trough where they come in contact with the flow of molten metal. It is obvious'that the funnel 29 can be of various sizes with varying converging angles to suit the speed at which it is desired to have the ingredients flow therethrough for introduction into the stream of molten metal flowing in the trough A. k

In order to prevent the cooling of the molten metal as it flows through the conveyor id and to keep extraneous material out of the conveyor, a layer of refractory material 30 is provided which covers the upper surface of the conveyor and maintains the heat losses at a minimum. This refractory layer may be of rigid material or, if desirable, may be of loose material supported on the conveyor by means of a plate 3i 7 of any suitable material.

When it is desired to withdraw an amount of molten metal from the cupola furnace fortne pouring of molds in which it is necessaryto use a metal having predetermined physical and/or chemical characteristics, the invention is utilized as follows: It is to be understood thatin accord ance with the usual practice in operating cupcia furnaces of the general type disclosed, an operatorhas an accurate control of the molten metal which issuesfrom-the cupolahymaintainixig a careful check upon thescrap materials which are loaded into the upperend v of the cuticle. fines"- much as the operator can control the chen'zicai and physical properties of the metal which issues from the furnace, and knowing the'type or metal that he desires for pouring his molds, he can add to the molten metal as -it iilovvs'"through the trough iSAof the conveyor. 5 3 such ingredients as will give the final result. he desires.

As is well-known inthe art'the ventcpening of the cupolakfurnaceis contreiled by an operator who, in the present instance, may conven 'ie'ntly stand upon the platform iZirom' jvihich point he can'easily control the how of rnoiten meta-1 Wing through b.- 1 i=ii A. when a suilicient quantity or metal has flowed throug the p i g. 51 .it is closed" thicug g m r ial dependence 'seaste cio e the mum of thesoitrefractory ina vent, the operator merely 3'8 lov n it; s ri -eta;

] the-amount of m'a'ter [ls that must then olten metaliin rial tote added c lien me uniform flow of molten metal,to -become,established through the trough uni so that meridiaing over" or ffolding back operation described with reference to thehailles B; C and. p, is well established and also, that the molten metal fills enclosure E with, a swirling action centering in the aperture 2| from which thevmolten metal flows into theladla, At this time the operator adds the ingredients which areto be dis- 10 solved into the molten metal. These may'be added either manually or semi-automatically,jas desired. v

A very convenientmethod of accomplishing this is to place a container C on theplatform i2, near the operator, which contains a relatively large supply of material to be added. A measure of predetermined volume may be utilized in transferring the ingredients from the container C tolthe funnel 29 where they flow-throughthe aperture MA of the refractory tube'to the slot in the trough MA, as has already been desc'ribed.- Another method of measuring the ingredients may involvethe use of a saint-automatic measuring device indicated diagrammatically at S In this case, the device S is positicnedimmediately j above the funnel 29 and when the operator actuates a handle'H, a predetermined quantityof the ingredient to be added flows from the conftainer S into the funnel 29, with the same results *already'described. g As has already been described, ingredients to beadded'slowlyfiow fromthe funnel '22 through the aperture 26A into the troughldA and float :upon the molten metal which is flowing through theslot under the tube 26 andtarecarri'ed -along the V trough MA until the 1 molten metal, which is flowing around the outside of the tube 25A,ls thrown back by'the side walls of, the 40 trough to fold over upon themolten metal which is issuing from the trough 25, carrying on its-sun face the addedingredients, This ioldingover :1 of the moltenmetal upon the ingredientsfcompletely surroundsandsubmerges themfand raises their temperature to a point where" theyrnayfbe rea l nc -nee mi "thelmeii m iel; vi A a et h awn ina hrqus 'ihe rwwe i ca f rfand t e, pl e gwer t h 1 m n et c" h ns-me ed? ii fi i it t "s mi ,i t v i c u n memes met "fwili'he,againsuhmergedl" Eacht he "lten metal-"isgivena reverse direet'iox airflow,

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metal are relatively coarse and are broken up into particles of relatively large size, it is advantageous to expose the materials for as long a period as possible to the high temperatures of the molten metal and it is, therefore, added to the molten metal as early as possible in the conveyor. Should, however, the added ingredients be finely divided or in powdery form, they may be added at the swirl at the distal end of the conveyor. The small particles will readily reach the high temperatureof the molten metal and will be readily dissolved in the molten metal.

The above method and apparatus has been used with success for adding various alloying material to metal, such as, manganese, nickel, chromium, vanadium, titanium, molybdenum, copper, etc., and it is clear that any type of material which is capable of being dissolved in the molten metal, such as, deoxidizing and desulphurizing agents, may also be added in this way. Graphitic carbon is also readily added by this process.

It is to be understood that the above detailed description of the present invention is intended to disclose an embodiment thereof to those skilled in the art, but that the invention is not to be construed as limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawing, since the invention is capable of being practiced and carried out in various ways without departing from the spirit of the invention. The language used in the specification relating to the operation and function of the elements of the invention is employed for purposes of description and not of limitation, and it is not intended to limit the scope of the following claims beyond the requirements of the prior art.

What is claimed:

1. Th method of introducing addition ingredients into molten metal, comprising creating a predetermined volumetric rate of flow of molten metal on a tortuous inclined tubular way to fill a container of predetermined volume, of adding a predetermined amount of addition ingredient adjacent the top of the inclined way at a predetermined rate, of maintaining the slope of the inclined way sufficient to create a turbulent flow in the molten metal, of creating a swirl in the molten metal in an enclosure on the lower end of the inclined way, and withdrawing the molten metal from the enclosure at the center of the swirl to fill the container, the rate of addition of the addition ingredient being capable of variation to suit the rate of flow of the molten metal as compared with the volume of the container to assure that the addition ingredient is added before the container is filled.

- 2. The method of introducing addition ingredients into molten metal, comprising creating a flow of molten metal on a tortuous inclined way terminating in a bottom-vented enclosure, adding the addition ingredient adjacent the top of the inclined way at a predetermined rate to the molten metal, and maintaining the slope of the inclined way suilicient to create a turbulent flow in the tortuous way, the molten metal thereby entering the enclosure at a rate to create a swirl centering in the vent in the bottom of the enclosure whereby non-included addition ingredients floating on the surface of the metal will be sucked into the core of the molten metal flowing out the vent into a container below.

3. The methodof introducing addition ingreflow of molten metal on a tortuous inclined way, of adding the addition ingredient near the top of the inclined way, maintaining the slope of the inclined way sufllcient to cause a turbulence in the flow of the molten metal to include the addition ingredient into the body of the molten metal, collecting the molten metal at the termination of the inclined way in an enclosure by a tangential flow whereby a swirl is created, and allowing the molten metal to flow out from the enclosure through a bottom vent to draw addition ingredients floating on the surface of the molten metal into the core 'of molten metal flowing through the vent into a ladle for pouring.

4. The method of introducing addition ingredients into molten metal comprising, creating a flow of molten metal on a tortuous inclined way, of adding the addition ingredient near the top of the inclined way, maintaining the slope of the inclined way sufllcient to cause a turbulence in the flow of the molten metal whereby the molten metal will fold over at the bends of the tortuous way to cover any addition ingredients floating on its surface, creating a swirl in the molten metal at the lower end of the inclined way in an enclosure, and withdrawing the molten metal from the enclosure at the center 0! the swirl to insure maximum inclusion of the addition ingredient.

5. In a device of the class described, a controllable source of molten metal, a sloping tubuiar conveyor cooperating with the source to convey the molten metal from the source to a container under the influence of gravity, means extending below the surface of the molten metal flowing in the conveyor adjacent the upper end to introduce addition ingredients into the molten metal, baille means in the conveyor to create a tortuous path, the rate of flow causing a turbulence in the molten metal flowing in the conveyor to insure inclusion of the addition ingredient into the molten metal, and bottom-vented enclosure means at the lower end of the conveyor to create a swirl in the molten metal adjacent the outlet of the conveyor to draw addition ingredient floating on the surface of the metal into the'core of the metal flowing into the container.

6. In a device of the class described, an inclined tubular conveyor having a tortuous way for molten metal, a bottom-vented enclosure on the lower end of the conveyor into which the molten metal enters in a tangential direction from the tortuous way, and means adjacent the upper end of the conveyor to introduce addition ingredients into the center of the flowing molten metal, the slope of the inclined conveyor being suflicient to cause a turbulent flow in the molten metal down the tortuous way and to enter the enclosure at a rate suflicientto cause a swirl therein whereby addition ingredients floating on the surface of the molten metal will be drawn in the stream-of metal issuing from the vent in the bottom of the enclosure.

7. In a device of the class described, a troughlike conveyor having a tortuous way for conveying molten metal from a source to a container,

dients into molten metal, comprising creating a 76 an inlet adjacent the upper end of the conveyor, a bottom-vented enclosure on the lower end of the conveyor tengentially connected with the tortuous way, a cover for the trough-like conveyor and the enclosure extending over the conveyor except a portion adjacent the inlet, a tube-like member extending upwardly from the floor of the trough-like conveyor adjacent the tube-like member to the molten metal flowing in the conveyor, a longitudinal slot in the floor of the trough-like conveyor coincident with the aperture in the tube -like member and a vent in the floor of the enclosure at the bottom end of the trough-like conveyor, the slope of the conveyor being such that molten metal willflo'w along the slot in the floor oi the trough under the tube-like member and also around the tubelike member, whereby a turbulence is created on the lower side of the tube-like member to introduce the addition ingredients into the center of the stream of molten metal, which then flows -in the tortuous way into the enclosure in a tangential direction to create aswirl whose center is located over the vent in the floor of the enclosure, so that addition ingredients floating on the surface will be drawn into the stream of molten metal issuing from the vent into the container below.

- WILLIAM A. O'BRIEN.

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