|Publication number||US3696860 A|
|Publication date||Oct 10, 1972|
|Filing date||Jun 20, 1971|
|Priority date||Jun 20, 1971|
|Publication number||US 3696860 A, US 3696860A, US-A-3696860, US3696860 A, US3696860A|
|Original Assignee||Colombo Piero|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (8), Referenced by (2), Classifications (8)|
|External Links: USPTO, USPTO Assignment, Espacenet|
. United States Patent Colombo Oct. 10, 1972  METHOD AND APPARATUS FOR THE 2,790,216 4/1957 Hunter ..164/277 CONTINUOUS CASTING OF FLAT 2,804,667 9/ 1957 Townhill 164/87 BLOOMS OR THE LIKE 3,038,219 6/ 1962 Hudson 164/27 7 3,447,590 6/1969 Olsson ..164 277  33:3 igf 3,520,352 7/1970 'Hess ..164/123X  Filed: I June 2, 1971 Primary Examiner-R. Spencer Annear [211 App] No 149 337 Attorney-Berman, Davidson and Berman  ABSTRACT  US. Cl. ..164/73, 164/82, 116644226883; The invention provides a process of and a continuous  Int Cl 822d 11/00 casting mould for, continuous casting of metals by pouring molten metal into a mould in a manner such  Flew of 2ih that the metal issues from the mould as a core of still fluid metal encased in a solidified outer sleeve. The sleeve is formed in the mould by the casting of two  References cued sections of U-shaped cross-section with the lateral UNITED STATES PATENTS limbs of the U facing and opposed to each other and the facing limbs are engaged with and welded one to 2 Egg? the other as they pass through the mould.
2,597,046 5/1952 Sendziminl ..164/87 7 Claims, 7 Drawing Figures V P'ATENTEDnm 10 I972 SHEEI 1 OF 4 INVENTOR P/ 56 o 004 0 M50,
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METHOD AND APPARATUS FOR THE CONTINUOUS CASTING OF FLAT BLOOMS OR- THE LIKE BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a process for the continuous casting of metals in the form of slabs, plates and the like, in a vertical continuous casting mould, which consists of two opposed, approximately parallel transverse walls corresponding to the shorter cross-section sides of the metal line to be cast, and of two opposed cooled longitudinal sides corresponding to the longer crosssection sides of the metal line to be cast and converging downwards at least along a part of the height of the mould, so that two initially separate metal layers sliding down the convergent walls and are concomitantly solidified continuously on the longitudinal walls of the continuous casting mould and are brought into contact with each other and are welded together approximately in the area of the smallest distance between the longitudinal sides of the mould.
' 2. Description of the Prior Art In the process of this kind known until now, the metal layers solidifying on the convergent longitudinal sides of the continuous casting mould possess an approximately plane parallel rectangular cross-section corresponding to approximately half the cross-section of the metal section in the area of the shortest distance between the longitudinal sides. After the mutual contact and welding action, these two metal layers produce an essentially fully solidified metal section within the continuous casting mould itself, which no longer has a liquid core after issuing from the mould.
With this known process, it is difficult or practically impossible to produce metal sections and specifically slabs or blooms of relatively great thickness, because the metal layers solidified in the continuous casting mould on the longitudinal sides thereof must possess a correspondingly greater thickness. In the case of some metals, and of steel in particular, it is appropriate moreover for the cast metal section to' retain a molten fluid portion after issuing from the continuous casting mould, whose cross-section diminishes downwards continually until the core of the section has solidified, owing to a subsequent so-called secondary cooling section.
It is an object of the invention to develop a process of the nature described initially, for the continuous casting of metals in the form of slabs, plates and the like, which renders it possible to produce metal sections of optional, i.e., even substantial thickness, under formation of a liquid section core solidifying after the emergence of the section from the continuous casting mould.
SUMMARY According to the invention, this problem is resolved by virtue of the fact that in the continuous casting mould and on each longitudinal edge of the two metal layers solidified on the longitudinal sides of the mould, a flange extending transversely to the corresponding metal layer and integral therewith is solidified on the adjacent marginal area of the transversal sides of the mould, and the solidified metal layers thus obtained, which are approximately U-shaped in cross-section, are
pressed against each other and welded together only by the lateral and oppositely projecting limbs of the U-sections thereby forming a metal section comprising an annularly closed solidified barrel or sheath and a fluid core.
A continuous casting mould for carrying out the process comprises two opposed vertical transverse walls approximately parallel one to the other and corresponding to the shorter cross-section sides of the metal section which is to be cast, and two cooled and opposed longitudinal walls converging downwardly along at least a part of the height of the mould and corresponding to the longer cross-section sides of the metal section which is to be cast, characterized in that the opposed longitudinal walls each possess an inward delimiting surface which in cross-section is concave and approximately U-shaped, and that the inwardly projecting lateral parts of these longitudinal walls flanking the corners of themould space, form the marginal parts of the corresponding transverse walls and are cooled.
With this arrangement of the longitudinal sides of the continuous casting mould, a metal layer whose lateral limbs are formed on inwardly projecting and cooled lateral parts of the longitudinal side, are solidified on the concave U-shaped inward surface of each cooled longitudinal side, these metal layers being of corresponding U-shape.
In the process according to the invention, it is of importance that the two U-shaped metal layers which are caused to solidify on the longitudinal sides of the continuous casting mould and are downwardly convergent, are initially separated from each other, i.e., in the upper region of the mould, so that they are free to slide downwards independently of each other and can be pressed against eachother with their lateral limbs only in a lower region of the mould, say in the area of the shortest distance between the converging longitudinal sides, This initial separation between the two U-shaped solidified metal layers may be produced in manner known per se by virtue of the fact that the middle portion of each transverse side of, the continuous casting mould situated between the two corresponding, oppositely projecting and cooled lateral parts of the longitudinal sides, is kept so hot, in the upper portion of the mould at least, by means of thermal insulation and/or heating, that the metal remains molten and fluid thereon. This known embodiment, which is essentially applicable without difficulty in combination with the process according to the invention, has the disadvantage however that, on the one hand, the heating of the transverse sides of the continuous casting mould requires additional expenditure, and on the other hand, that the thermal insulation of the transverse sides becomes worn away very quickly and must accordingly be frequently replaced, especially if it consists of an internal refractory coating, as is required in most instances.
In further development of the inventive process, these disadvantages are eliminated by virtue of the fact that the middle portion of each transverse side of the continuous casting mould situated between the corresponding oppositely projecting lateral limbs of the U- shaped metal layers solidified on the longitudinal sides of the mould is devised to possess a heat dissipation capacity, and contingently to be cooled, of such magnitude that a stationary metal layer possessing a constant thickness after establishment of thermal balance, is caused to solidify thereon, which layer is separated from the adjacent lateral flanges of the U-shaped metal layers by means of relatively thin layers of molten fluid metal.
A first form of continuous casting mould for the application of this developed process is characterized in that joints of thermally insulating refractory material are separatingly arranged between the oppositely projecting lateral parts of the longitudinal sides of the mould and the middle portion of the transverse sides flanked by these lateral parts. In this arrangement, the metal remains fluid in. the area of the thermally insulating separating joints between the lateral parts of the longitudinal sides and the middle portion of the transverse sides, and thereby assures the required separation between the U-shaped metal layers formed on the longitudinal sides and sliding downwards convergently, and the stationary metal layers solidified on the middle portion of the transverse sides. The thin separating joints of thermally insulating refractory material incur a relatively low degree of wear and. may be replaced at relatively low cost.
Another embodiment of the continuous, casting mould for the application of the developed process is characterized in that between the oppositely projecting lateral parts of the longitudinal sides of the mould and the middle portion of the transverse sides flanked by these lateral parts, open interstices are arranged, through which lubricating oil flows into the mould under pressure. In this embodiment, the inflowing pressurized oil prevents the emergence of the molten fluid metal through the interstice between the longitudinal and transverse sides of the continuous casting mould, as well as the formation of a solidified connecting web between the U-shaped metal layers formed on the longitudinal sides and sliding downwards convergently, and the stationary metal layers solidified on the middle portion of the transverse sides. This embodiment is advantageous, in particular for the continuous casting moulds known per se, in which the transverse sides of the mould are stationary whereas the two longitudinal sides swing upwards and downwards at the same time.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic elevation, partly in section ofa continuous casting mould,
FIG. 2 is a section through a first embodiment of a continuous casting mould according to the invention,
FIG. 3 is a section on line Ill-Ill, FIG. 2.
FIG. 4 is a perspective view of an upper part of a second embodiment of a continuous casting mould according to the invention,
FIG. 5 is a section through the mould of FIG. 4, and
FIGS. 6 and 7 are sections on the lines VI-VI and VIIVII, FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENT The continuous casting plant illustrated in FIG. 1 comprises a continuous water-cooled casting mould 1 possessing a straight vertical axis. The continuous casting mould l is arranged on a vertically reciprocable mould platform 2 which is displaceably guided in vertical guides 3. The vertical reciprocating motion of the mould plateform 2 is generated by means of at least one rocking lever or the like 4 which acts on an appropriate lower projection 102 of the mould platform 2. The pivotal axis 104 of the lever 4 is displaceable in the Iongitudinal direction of the lever 4 for variation of the amplitude of swing of the mould 1. The rocking lever 4 is driven by a cam 5 through a roller-carrying plunger 6.
The molten fluid metal is poured from a casting ladle 7, having a bottom plug outlet 8, into an intermediate casting or distributing container 9 situated below the outlet 8,-from which it is poured into the water cooled continuous casting mould 1. The cast section. S emerging from the lower opening of the continuous casting mould 1 possesses at least a solidified outer surface and initially travels along a straight vertical stretch which is defined by bearing rollers or cylinders l0 arranged to be freely rotatable and situated omnilaterally around the section. After this relatively short straight and vertical stretch, the cast section S is deflected laterally to the horizontal along the arc of a circle. The arcuate portion of the section is formed by means of freely rotating guide rollers 11, 12 whichengage the outer and the inner surfaces of curvature of the castsection S. The guide rollers 12 are spaced apart by distances greater than that between the rollers 1 1 and the rollers 12 may be replaced by stationary guiding cross-beams. After issuing from the continuous casting mould l, the cast section S is exposed to a subsequent cooling action along the vertical stretch in the area of the bearing rollers 10, as well as along the adjacent arcuate stretch in the area of the guide rollers 11, 12, in manner known per se, by means of water jet nozzles 33 illustrated in FIG. 5.
At the end of the arcuate stretch, the wholly solidified cast section S passes between two driving rollers 15, which are positioned one above the other, are pressed against each other hydraulically, and are driven by an electric motor 13 through a chain or the like 14. The driving rollers 15 are co-ordinated with a truing mechanism which effects the horizontal truing or straightening of the curved cast section S. The truing mechanism comprises a truing roller 16 situated downstream of the pair of driving rollers 15. The roller 16 rotates freely and is positioned above the cast sec tion S, and the roller 16 is journalled on a rocking or pivoted lever 17 and is pressed against the section S by means of at least one hydraulic cylinder 18. Also forming part of the truing mechanism is a counterthrust roller 19 which is positioned above the cast section S at the intake side of the pair of driving rollers 15.
The counterthrust roller 19 at the intake side of the truing mechanism may act in conjunction with a roller 21 situated at the underside of the cast section S and which is pressed towards the counterthrust roller 19 by means-of at least one hydraulic cylinder 20, as shown by broken lines in FIG. 1. The two rollers 19, 21 may be employed as a complementary pair of driving rollers, drive being conveyed thereto from one following driving roller 15 through transmission means 22.
The continuous casting plant is equipped with a single electric motor 13, which drives the driving rollers 15 and the rollers 19, 21 through a reduction gear 23. The motor 13 also drives the cam 5.
After passing the truing mechanism, the section S is severed into single lengths by means of a flame cutting device 24 or the like which is reciprocatingly displaceable in the longitudinal direction of the section.
For the continuous casting of blooms, slabs or plates, i.e., of metal sections of approximately rectangular cross-section, a continuous casting plant of the kind described above employs a continuous casting mould 1 according to the invention which is illustrated in detail in FIGS. 2 and 3. This continuous casting mould 1 consists of two opposed longitudinal walls which are inwardly slightly convex in the vertical plane, converge downwards in funnel shape, and correspond to the longer cross-section sides of the metal section S which is to be cast, and of two opposed plane and vertical transverse walls 26 which are approximately triangular and correspond to the shorter cross-section sides of the metal section S which is to be cast. The longitudinal walls 25, as well as the transverse walls 26 are made of a metallic material and are cooled by circulation of water. To this end, the longitudinal and transverse walls 25, 26 possess cavities 27, 28, FIG. 3, which are traversed by cooling water. The longitudinal and transverse walls 25, 26 of the continuous casting mould 1 are rigidly interconnected and connected to the vertically reciprocable mould platform 2, and conjointly form a rigid unitary mould element.
In cross-section, the longitudinal walls possess concave and approximately U-shaped inward delimiting surfaces 29. The longitudinal walls 25 are accordingly provided at both ends of their cross-section with lateral parts which project inwards, see FIG. 3, approximately at right angles, and which flank the corners of the mould space and form the marginal parts of the corresponding transverse walls 26 of the mould. The lateral parts 30 of the longitudinal walls 25 are cooled to approximately the same degree as the other parts of the longitudinal walls 25 by means of appropriate lateral extensions of the cavities 27 which are traversed by cooling water.
Separating joints 31, FIG. 3, of thermally insulating refractory material are arranged between the oppositely projecting cooled lateral parts 30 of the longitudinal walls 25 of the mould l and the cooled middle portion of the transverse walls 26, which portions are of approximately wedge or triangular shape.
By this arrangement of the continuous casting mould, a corresponding cross-sectionally U-shaped metal layer S1 is solidified out of the molten metal cast into the mould, on the concave U-shap'ed inner surface 29 of each longitudinal wall 25 of the mould. The lateral limbs F of the two U-shaped metal layers S1 are then formed on the inwardly projecting lateral parts 30 of the longitudinal walls 25 and extend toward each other, as illustrated in FIG. 3. Corresponding approximately triangular metal layers M, FIG. 3, are also solidified on the cooled middle portion of the transverse walls 26 of the mould. In the area of the thermally insulated spacing joints 31 between the lateral parts 30 of the longitudinal walls 25 and the middle portion of the transverse walls 26, the metal cast into the mould 1 remains fluid and forms a molten fluid spacer between the triangular metal layers M solidified on the cooled middle portions of the transverse walls 26 and the adjacent lateral limbs F of the U-shaped metal layers S1 solidified on the longitudinal walls. Consequently, the
U-shaped metal layers S1 which, in the upper region of the mould l, are separated from each other and from the metal layers M on the transverse walls 26, can slide down unimpeded on the downwardly convergent longitudinal walls 25, the thickness and length of their lateral limbs F concomitantly increasing continually as diagrammatically shown in dash-dotted lines in FIG. 2. The triangular metal layers M solidified on the transverse walls 26 are stationary and their thickness assumes a constant value and the metal layers M act as insulating plates, i.e., they impede the dissipation of heat through the cooled transverse walls 26 to such degree that no metal can solidify on the inward side of the metal layers M.
In a lower area of the continuous casting mould 1, say in the area of the smallest gap between the convergent longitudinal walls 25, the U-shaped metal layers S1 formed and slipping down on the longitudinal walls 25, have their oppositely projecting lateral limbs F pressed together and welded to each other. A metal section S is formed thereby in the continuous casting mould 1, which consists of an annular closed solidified sleeve 81-81 and of a molten fluid core. This section S emerges from the lower opening of the mould 1 and is cooled along its further rectilinear and vertical path in the area of the bearing rollers 10 and along the subsequent arcuate path in the area of the guide rollers 11, 12, until its molten fluid core K FIG. 3, has been solidified completely.
The continuous casting mould 101 illustrated in FIGS. 4 to 7 also consists of two opposed vertical and plane transverse walls 126 which are parallel to each other, approximately triangular in elevation and corresponding to the shorter cross-section sides of the metal section S which is to be cast, and of two opposed and downwardly convergent longitudinal walls corresponding to the longer cross-section sides of the metal section S which is to be cast. The longitudinal walls 125 are inwardly convex in the vertical plane and are shaped in the form of cylinder jacket sectors. The smallest gap between the convex longitudinal walls 125 is situated approximately in the central part of the mould, so that the mould 101, FIG. 4, has a form in longitudinal section which converges downwards in its upper portion and diverges downwards in its lower portron.
The approximately triangular transverse walls 126 of the mould 101 are stationary, whereas the convex longitudinal walls 125 oscillate up and down at the same time about an axis in each case which is external, horizontal and, for example, coincident with the geometrical center of the corresponding cylinder jacket sector. The bearing, guiding and driving arrangements for the vertically oscillating longitudinal walls 125 of the mould 101 may be of optional nature. In the example illustrated, each longitudinal wall 125 made in the form of a cylinder jacket sector, runs on an external appropriately curved roller path 32 which is co-axial with the axis of the corresponding cylinder section.
The longitudinal walls 125 of the mould 101 possess a concave U-shaped inward delimiting surface 129, FIGS. 4, 6 and 7, and are cooled as uniformly as possible by circulatory cooling. To this end, the longitudinal walls 125 possess internal cavities 127, FIGS. 5 to 7, traversed by cooling water, which also extend into the oppositely projecting lateral parts 130, FIG. 4, of the longitudinal walls flanking the corners of the mould space, as illustrated in FIGS. 6 and 7 in particular. Consequently, two metal layers S1, of U-shaped cross-section, possessing oppositely directed lateral limbs F are solidified in this mould on the longitudinal walls 125 and on the oppositely projecting lateral parts 130 thereof. The U-shaped metal layers S1 slide down on the longitudinal walls 125 owing to their vertical oscillatory motion and are pressed together and welded to each other, say in the area of the smallest gap between the longitudinal walls 125, but only with their lateral limbs F, as illustrated in FIG. 7. This forms a metal section S consisting of a solidified casing sleeve 81-81 and of a molten fluid core K, and which undergoes subsequent cooling along its trajectory after its emergence from the continuous casting mould 101 by means of water jet nozzles 33, until its solidification has been completed.
In the example according to FIGS. 4 to 7, the transverse walls 126 are not cooled by means of special cooing devices, and may also consist of thermally insulating refractory material. The transverse walls 126 are so contrived however, that the quantity of heat dissipated therefrom results in the solidification of a metal layer M on the inward side of each transverse wall 126, as illustrated in FIG. 6. These approximately triangular metal layers M are stationary and their thickness assumes a constant value after thermal balance has been reached. Consequently, the metal layers M form an inward lining affording a protection against wear for the transverse walls 126 contingently consisting of refractory material.
To separate the stationary triangular metal layers M formed on the transverse walls 126, from the U-shaped metal layers 81 formed on the longitudinal walls 125 and sliding downwards convergently, downwardly convergent open gaps 34, FIG. 5, are arranged between the oppositely projecting lateral parts 130 of the longitudinal walls 125 and the middle portion of the transverse walls 126 flanked by these lateral parts. Through the gaps 34, and by means of feed pipes 35 and of passages 36 formed in the walls of the mould, lubricating oil is forced into the mould space; The lubricating oil concomitantly flows into the mould 101 under such pressure that, on the one hand, the molten fluid metal can-- not emerge through the gap 34, and on the other hand, the metal remains fluid in the area between the metal layers M solidified on the transverse walls 126 and the adjacent lateral .limbs F of the U-shaped metal layers S1. Moreover, the pressurized oil provides a sealing lubrication between the stationary transverse walls 126 and the vertically oscillating longitudinal walls 125.
The invention is evidently not limited to the examples of embodiment illustrated, but may be modified within the ambit of the general principle of the invention, specifically in the structural sense. Instead of the thermally insulating separating joints 31, the infeed of pressurized oilthrough the gaps 34 according to FIGS. 4 to 7, may also be incorporated in the continuous casting mould 1 accordingvto FIG. 2.
What is claimed is:
l. A process for the continuous casting of metals in the form of slabs, plates, and the like, comprising the steps of pouring melted metal into vertical, continuous casting mould formed of at least four walls separated by narrow gaps and convergent in its top portion and open .at its bottom, cooling the walls of said mould so as to form stationary solid metal layers adjacent a pair of opposite mould walls spaced from two moving solid metal layers adjacent another pair of opposite mould walls, said moving layers conforming In shape to the adjacent walls and being of U-shape in horizontal section with inwardly disposed lateral solid limbs disposed about a core of melted metal separating all of said layers feeding a fluid under pressure through said gaps to the spaces between said stationary and moving solid metal layers to prevent egress of melted metal from the mould through said gaps and to prevent cooling and hardening of the melted metal in the spaces between said moving and stationary solid metal layers, continuously drawing said moving solid metal layers downwardly until their lateral solid limbs contact along their edges while maintaining a core of melted metal inside said solid metal layers and said solid metal limbs, cooling and pressing said solid metal contacted limbs together in a lower portion of the mould to'weld the limbs together before the casting leaves the mould, continuously extracting the metal casting with its melted metal core from the open bottom of the mould, and completely solidifying the casting after it has left the mould while leaving the said stationary solid metal layers inside of the mould.
2. A continuous casting mould with an open end comprising two opposed vertical transverse walls of approximately triangular shape and approximately parallel to one another, and two cooled and opposed longitudinal walls converging downwardly along at least a part of the height of the mould, said opposed longitudinal walls each having an inward de-limiting surface which is concave and approximately U-shaped in horizontal section with inwardly projecting lateral parts flanking the corners of the mould space to form marginal extensions of the adjacent transverse walls, said longitudinal and transverse walls being separated by gaps of narrow width, means for preventing heat loss through said narrow gaps, and means for cooling said longitudinal walls.
3. A continuous casting mould according to claim 2, wherein said narrow gaps between the longitudinal and transverse walls are filled by spacers formed of thermally insulating refractory material.
4. A continuous casting mould according to claim 3, wherein means is provided to conduct a flow of a lubricating oil under pressure into said narrow gaps whereby to prevent the egress of melted casting metal therethrough and to maintain ribbons of molten metal as spacers between solidified layers of casting metal formed on the longitudinal and transverse walls during casting.
5. A continuous casting mould according to claim 3, wherein at least portions of the transverse walls between said thermally insulating spacers are provided with cavities arranged to be traversed by cooling water.
6. A continuous casting mould according to claim 2, wherein said transverse walls are formed at least partially of thermally insulating refractory material.
7. A continuous casting mould according to claim 2, wherein means are provided for heating at least portions of said transverse walls.
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|U.S. Classification||164/472, 164/268, 164/442, 164/443, 164/416|