DE2206606A1 - Continuous casting process and device - Google Patents

Description

DR. ING. E. HOFFMANN · DIPL. ING. W. EITLE DR. RER. NAT. K. HOFFMANN

PATENT LAWYERS D.8000 MÖNCHEN 81ARABEUASTRASSE 4 TELEPHONE (0811) 911087

Irving Rossi, Morristown, New Jersey / USA

Continuous casting process and apparatus

The invention relates to a method and a metal casting device with a tubular mold and means for cooling the same, the mold being a pair of oppositely disposed after has sidewalls curved inward towards one another and is arranged with one end above the other, and Molten metal poured into a continuous strand with an outer edge zone of solidified metal which encloses a molten core and wherein the edge zone is a pair opposite one another having arranged, concave curved surfaces. It is particularly useful for the continuous casting of billets suitable.

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According to the DT-PS (patent application P 21 44 082.4) Metal in the molten state in a tubular mold with a pair of opposing side walls cast, which are curved inward towards each other in order to convert the metal into relatively wide-area slabs with a outer edge zone of solidified metal and a molten core to be poured. The side faces of the slab are Curved in the transverse direction to prevent buckling due to the ferrostatic pressure that is present in the molten metal Core is present. The cast slab is taken up between rollers at the outlet opening of the mold, which rest on opposite edges of the slab with sufficient force to avoid the edges of the slab and its concave ones to support wide side surfaces against bulging.

However, a problem arises in that it is difficult to determine the temperature of a molten metal, e.g. steel, to be precisely regulated if it is in a continuous casting plant - usually in a ladle from a Thomas pear or the like. The steel usually leaves to compensate for the cooling that takes place in the intervening period the furnace with some overheating, which must have been lost before the metal reaches a temperature of is brought about 1 4 ^ 0 - 1 54o ° C (2 600 - 2 800 ° P), at which the solidification can begin, because otherwise there is a tendency for the extremely thin-walled edge zone to break the slab is made at the start of casting. This tendency is more serious that the mold is below the area at which the metal separates from the mold, due to the passage between the metal and the mold the shrinkage of the metal during the transition from the molten to the solid state creates an area has poor cooling.

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The object of the invention is to provide devices with which a bulging of the side walls of the Slab or a breaking of the thin-walled edge zone is prevented.

According to the invention, this object is achieved in that adjoining the outlet of the mold is one of the concavely curved Surface of the cast edge zone adjacent device for mechanical support of the same against breakage arranged and devices for cooling the strand supported in this way are provided.

According to an exemplary embodiment of the invention, this double effect is essentially followed by attached to the oppositely arranged curved exit edges of the mold grids or net-like Reached plates with a similar curved course, which rest on the surfaces and so the concave slab surfaces mechanically support, while the same are intensively sprayed with a coolant, which is injected through the grid openings or plates arranged like a grid.

Both in the continuous casting of billets and slabs are in the known device and the known Method used water-cooled tubular molds, which at an elevated position in relation to are attached to the ground and are arranged with their upper end above their lower end to that of a Tundish exposing molten metal poured into the mold to gravity. To start the workflow, a plug or a replacement slab is used, one end of which at the bottom into the mold opening

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is inserted and sealed. The end so inserted has a ring, hook, wedge or the like. Around which part of the cast metal solidifies, whereupon the replacement slab, followed by a continuous billet strand, is pulled out, which consists of a solidified edge zone and a molten metal core.

Leadershipar) e.g. leadership roles, are usually below the mold arranged to guide the cast strand on a predetermined path which extends from the Shape can extend vertically downwards. But generally this path extends in an arc in one horizontal, tangential direction to the side, where a straightening device with power-operated rollers for straightening of the cast strand is arranged before passing through a cutting device, where the strand is cut into sections is divided. Coolant sprays are along the side path for progressively increasing the thickness the solidified edge zone provided until the strand is solidified substantially throughout when it is in the Straightening device occurs.

In these known arrangements, the strand on the guide devices by the power-operated Rolls of the straightening device pulled out of the mold. Because the hot rod, especially the one made of steel, is considerably weaker in the direction of pull than in the direction of compression, it must be cooled and solidified quickly, while it runs along the guide devices to avoid a break through the completely from below through the Straightening device to prevent train exerted. However, when the billet strand is so progressively solidified, it will progressively stiffer and requires massive, powered rollers in the straightener to make the strand to pull through the guiding devices and then to judge him.

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In marked contrast to this known working method, an apparatus and a method are provided according to the invention created in which the cast strand driven by the guide rollers by one or more pairs Rolls, which are arranged between the mold and the guide devices, is pushed. Because, as stated above, the hot metal of the strand is much stronger in the direction of compression than in the direction of tension is, he can therefore from the guide rollers in a hotter and therefore more plastic and more flexible state and with small thickness of the solidified edge zone of the strand are pushed through the guide device than for pulling of the strand is necessary through the guide devices according to known practice.

To ensure that the billet strand follows a desired predetermined path as it is pushed through the guide means, a tubular guide is used provided through which the strand is pushed. The guide preferably has an arcuate shape in the longitudinal direction Course to lead the strand from the mold tangentially in a horizontal lateral direction, so it can pass through a cutting device.

Because the strand is kept in a sufficiently hot and plastic state when it passes through the tubular Guide is pushed, it slides along and down in the guide essentially due to its own weight is guided through the tubular guide and aligns itself in a horizontally arranged lower end section the guide straight, whereby the known straightening device used can be dispensed with and the strand directly can be passed from the guide to a cutting device for cutting into sections.

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To ensure that the hardened edge zone of the cast strand has become sufficiently thick after it is gripped by the driven rollers, which between the The mold and the tubular guide are arranged to push the strand through the tubular guide part, is also in the device according to the invention an open latticework with a row of spaced rods provided, which is attached to the underside of the mold and down along a curved path and then extends to a distance just before the arrangement of the driven rollers. Spray nozzles are along and around that Grid for spraying a cooling liquid, e.g. cold water, on the billet strand when it is coming from the mold passes through the driven rollers. As a result, the solidified edge zone of the strand quickly becomes sufficient Increased depth and strength so that it can withstand roller pressure. The tubular guide has guide rails or rolls on the inside to guide the billet strand through. The tubular guide carries along its course and all around also spray nozzles, around a cooling liquid, e.g. cold water, on the billet strand to spray when it passes through the guide.

In the device according to the invention, a relatively short plug or a bag-like closed plug is used to start pouring Pipe of articulated construction, i.e. a so-called "replacement slab", is used. She is through the mold after Can be used at the bottom until its upper end seals the base of the mold, the lower end of the replacement slab is gripped by the rollers of the top pair of driven rollers. At the upper end of the replacement slab there is an approach a hook or the like. Attached to which the strand is attached when the molten metal poured around it solidifies is anchored so as to drive the continuous casting process

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the aforementioned pair of rollers in a direction for pulling out the plug from the mold followed by To begin billet strand. The driven rollers push the replacement slab and the one attached to it The billet is then cut through the tubular guide to the cutting device, where the billet is cut from the stopper in order to be able to remove it from the lateral movement path of the strand.

According to the invention the cooling is of cast billets strand to a temperature of about 65O 1 10O ⁰ C (1200-2000 ⁰ P) be adjusted when it passes from the mold in the horizontal transverse direction, so that the casting itself by gravity within a horizontally disposed end portion of the tubular guide is straightened and completely solidified when it enters the shear device. Therefore, the casting apparatus can be constructed relatively easily and economically. Also, the size and drive of the scissors can be reduced accordingly because the billet is cut while it is hot but solidified.

The invention is explained in more detail below with reference to the drawing. Show it:

Fig. 1 is a front view of a partially axially cut mold, a grid for Abäützen the slab surface and a spray nozzle arrangement of an embodiment of the invention,

Fig. 2

and 3 cross sections along lines 2-2 and 3-3 of Fig. 1,

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Figure 4 is a front view of one of the Pig. I similar arrangement with a modified type of lattice structure to support the slab surface,

Fig. 5 is a cross-section along line 5-5 of Fig. 4;

FIG. 6 is a view similar to that of FIG. 4, but with a support plate for the slab surface according to a further embodiment of the invention,

FIG. 7 shows a section along the line 7-7 of FIG. 6,

8 shows a side view, partly in longitudinal section, of a device according to a further embodiment piel of the invention, which briefly describes the device used for continuously casting a metal slab after the start of pouring,

Fig. 9

to 12 cross sections along lines 9-9 to 12-12 of Fig. 8,

13 shows a detail from FIG. 8, which shows the start of casting the device with the help of an articulated replacement slab,

Fig. 14 is a longitudinal section of a Ersatzbramme, as shown in side view in Fig. IJ>, and

14a shows a section along the line I4a-14a of FIG.

In FIGS. 1 to J5 there is a vertically arranged tubular Chill 10 made of copper with a jacket 11 for the circulation of a liquid coolant 12, for example water

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arranged the mold. The coolant is supplied and discharged through inlet and outlet pipes I3 and 14, respectively. As can be seen in Fig. 2 in cross section, the mold is provided with a pair of oppositely arranged, relatively wide side walls 15, 16, which are curved inwardly towards each other and with a pair of oppositely arranged, relatively narrow end walls 17 * 18, which are arranged essentially parallel to one another. The end walls are chamfered at the corners 19, 20 and connected to the adjacent sections 21, 22 of the side walls, which are arranged essentially parallel to one another and which in turn are connected to the inwardly curved sections of the side walls 15, 16 shown in the drawing Way are connected. Like in Pig. 2, the cooling jacket 11 has the same shape as the mold 10, but with a larger cross-section and is arranged coaxially to the mold in order to produce a substantially constant distance between the walls of the cooling jacket and the mold. In Fig. 1 it can be seen that a tundish 25 with a central opening for pouring molten metal, for example steel, from a tundish charge 27 is arranged above the mold. The molten metal flows in a jet 28 through the opening 26 into the cavity 29 of the mold. Due to the cooling effect of the cooling jacket 11, the liquid metal in contact with the mold hardens quickly, so that the molten metal is cast into a continuous slab yi , which consists of an outer solidified edge zone 30 and a molten metal core 32. During the transition from the molten state, the metal shrinks away from the mold, for example at 30a, and leaves a twin space 30b between the mold and the edge zone of the slab. As can be seen in FIGS. 2 and 3, the

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solidified edge zone 30 of the slab when it is in the mold is cast, the same cross-sectional shape as the cavity of the mold, the wide side surfaces 34, 35 of the Edge zone of the slab are concavely curved, end in flat sections 36, 37 and with chamfered corners 38, 39 are connected to the substantially parallel parts 40, 41 of the edge zone of the slab. In the embodiment the invention according to FIGS. 1 to 3 is below the mold a pair of spaced-apart, reticulated Elements consisting of grids 45, 46 made of metal are arranged. Each grid is made up of spaced apart vertically arranged rods 48 which are connected to transverse rods 49 arranged horizontally at a distance from one another are. As can be seen in Figure 3, the grids are

45 and 46 corresponding to the transversely curved design of concave side surfaces 3 ^ and 35 of the slab are curved and the grids are arranged as shown so that they press against the concave side surfaces of the slab and support them against breakage or bulging.

When the slab strand is inserted between the grids, it is by spraying cold water from spray nozzles 50, 51 exposed to an intensive cooling effect. Most of the water is through the grille openings sprayed on the concave surfaces of the slab strand, but part is also sprayed on the grids themselves, to prevent them from overheating. The grids are preferably made of copper or other heat resistant Metal made with high thermal conductivity.

When the slab strand from the supporting grids 45,

46 comes out it is received at the ends between a pair of rollers 52, 53 which are opposite to each other Capture ends of the continuous slab. This serves once

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the purpose of compressing the slab lengthwise and its withdrawal from the mold as at 30a to facilitate. Another purpose is that by compressing the strand in width, also the concavity the concave side surfaces of the slab as further security is ensured against bulging or breakage of the initially thin-walled slab strand.

FIGS. 4 and 5 show a modified grid structure for supporting the concave side surfaces of the slab against the breakage of the edge zone 30 of the slab. In this embodiment the vertical parts of the grid structure consist of heavy copper plates 60, 61, which as shown by horizontal, e.g. B. connected by welding to the vertical parts cross bars 63, 64, 65 parallel be kept at a distance from each other. As shown in Fig. 5, the grids, seen in cross section, have a curved structure and the vertical parts lie on the curved side surfaces 3 ^ and 35 of the edge zone 30 of the Slab to support it against breakage. The vertical parts are provided with a series of through holes 67 * 68 and in Fig. 5 a row of spray nozzles is shown, which on each side of the slab JH at 70 and 71 for spraying a liquid coolant, E.g. cold water as at 72, 73 »on the concave Face the slab through the holes in the grid between the vertical and horizontal parts and also through the holes 67, 68 are arranged in the vertical parts.

In the embodiment of FIG. 6, the support elements consist of triangular plates 80 with a curved cross-section, as shown in Fig. 7, which is with the adjacent concave side surface 35 of the edge zone 30 of the slab fits together. It is also shown in FIG. 7 how this

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Plates rest against the concave surfaces of the slab to support the same against breakage. The panels come with a Series of through holes 81 are provided and a series of spray nozzles 82 is cold opposite each plate for spraying Water or another liquid coolant through the holes 81 in the plate onto the surfaces of the slab strand arranged.

The arrangement shown in Figures 8 through 12 includes a tundish 110 of molten metal, in this case steel, which by gravity in a jet 111 into the upper end of a substantially vertical arranged tubular mold 112 is cast, which consists of a metal)! high thermal conductivity, e.g. copper. The mold is driven by a series of spray nozzles 113 cooled, which spray a liquid coolant, e.g. cold water, against all sides of the mold. This leads so that the molten steel adjacent to the mold walls, such as at 114 solidified to an outer edge zone of the poured metal, which molten a core Enclosing steel 115. The mold has a substantially rectangular cross section, as shown in Fig. 9 to to cast a continuous billet strand with a predetermined cross-section.

The billet strand produced in this way with :, its outer Solidified edge zone 114 and its molten core 115 emerges from the underside of the mold at II6, whereupon he passed through a grid of rods attached to the Underside of the mold are attached, formed passage passes through. This grid guides and supports the billet strand, as indicated by II7 and 118 in FIGS. 8 and 10 is. A series of spray nozzles II9, 120 are arranged around and along the grille around a liquid coolant. e.g.

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cold water, through the openings between the bars to spray on the billet strand and also on the bars themselves, so that the thickness of the solidified outer edge zone of the billet strand is increased rapidly, as can be seen in FIG. After passing through the grilles 117, 118 the billet strand runs between a pair of driven rollers 125, 126 (Figs. 8 and 11), which are each provided with a groove on the circumference or shaped differently as with 127, 128, 129 in Pig. Il shown is to capture the adjacent faces of billet 116 at 130, 131 so that the rollers all sides of the billet strand almost completely in the manner shown in FIG. 11. The rollers 125, 126 are over a transmission (not shown) with an electric motor (not shown) for driving the rollers in one Direction of rotation connected. When operating the system, as shown in Fig. 8, the rollers are in the direction driven that they promote the stick down and push it through a tubular guide I32, which is arranged below the rollers in the manner shown in FIG.

The tubular guide Ij52 is constructed as shown in FIGS. 8 and 12 and comprises a housing having an elongated, forked sectional structure. Sections I33, 134 are bolted together at points spaced along the length for easier assembly and disassembly, as at 135, 136. Each section has in its interior a series of longitudinally extending guide rails 137, 138, the inner ends of which form a passage for the cross section of the billet strand II6 and which together encompass all four walls of the billet strand in the manner shown in FIG. Spray nozzles penetrate the tubular guide 132 at a distance around the circumference

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and points l4o, 141, 142, 143, um distributed over the length on all sides of the billet strand over its entire length spray a coolant, e.g. water. These spray nozzles are set so that they achieve controlled cooling of the strand. As a result, the billet strand runs through the tubular Guide I32 and essentially adapts to the passage due to its own weight. Guide rollers can be used instead of guide rails 137 * 138.

After exiting the tubular guide 132 runs the billet strand via a cutting device 147, which cuts the billet strand in the desired lengths.

In order to start the continuous casting process as shown in FIGS. 8 to 12, as mentioned above, a Stopper or a spare I50 slab as used in the 14 and 14a is shown. It is shown in the in Fig. I3 used way. The replacement slab I50 shows preferably made of copper head part I5I, which is shaped to sealingly fit into the bottom of the mold 112 in the manner shown in FIG. The headboard I5I is provided with an extension 151a, preferably made of steel, so that part of the molten steel poured from the tundish into the mold solidified for anchoring the The base of the billet strand on the replacement slab solidified around the approach.

The head part I5I ends in a curved shape on its underside or spherically shaped, concave surface I52, which at a complementary convex curved or spherical Surface 153 rests against the upper end of a joint part 154 is trained. The hinge part 154 forms the first one Series of hinge parts 154 to I57 that are similarly shaped, so that they lie next to one another, as best shown in Flg. 14 can be seen. The series of parts I5I

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and 15 ^ to 157 is articulated to one another by one flexible strip I58 made of steel, which passes through slots of these parts and at its upper End at I60 is pinned to the head part I5I and on its lower end ends in a protruding threaded bolt 161 which is attached to the lower end of the strip I58 welded and surrounded by a helical compression spring I62, which is located between the lowermost joint part 157 and an end nut I63 is arranged on the threaded bolt is screwed. The replacement slab can be bent and according to the curvature and the horizontal Course are curved in the direction of the cutting device, behind which it is from the cast strand through the scissors are separated.

In Figs. I5 and Ik it can be seen how the lower end of the replacement slab I50 is inserted into the upper end of the mold 112 and pushed down until the head part 151 seals the base of the mold, and the lower end 157 with the rollers I25, 126 in the Fig. IjJ shown manner is engaged. The pouring of the molten steel from the tundish 110 into the mold is then started. After the metal around the extension 151a of the replacement slab has solidified, the rollers 125, 126 are driven in order to pull the same, followed by the cast billet strand, out of the mold. The replacement slab followed by the cast billet is then conveyed by the rollers down through the tubular guide 1 ^ 2 and then to the cutting device 147. When the replacement slab followed by the billet has passed through the cutting device, the same is actuated to close the end of the billet cut off as at I65 in the manner shown in FIG. The replacement slab is removed from the continuous casting line so that the casting process started in this way can be continued.

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The replacement slab I50, FIG. 14, is preferably made from Copper is produced and is produced during or before the liquid metal is introduced into the mold, sprayed so that the entering metal is immediately solidified and so the extraction of the replacement slab and the solidified Steel strand can be started quickly. Also, as in Pig. IjJ to see 1st, the mold straight or be curved and vibrate or vibrate or stand still.

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Claims (16)

Claims 1. Metal casting device with a tubular mold and means for cooling the same, wherein the mold has a pair of oppositely arranged, inwardly curved side walls and is arranged with one end above the other, and molten metal into a continuous strand with an outer rim of solidified Metal is cast which encloses a molten core and wherein the edge zone has a pair of oppositely arranged, concavely curved surfaces, characterized in that adjoining the outlet of the mold (10) is adjacent to the concavely curved surfaces of the cast edge zone (30) Means (45, 46) are arranged for mechanically supporting the same against breakage and means (50, 51; 70, 71; 82) are provided for cooling the strand (JiI) supported in this way. 2. Apparatus according to claim 1, characterized in that the supporting devices from consist of a pair of lattice-shaped, substantially rigid support elements which are spaced apart from each other in the are arranged essentially parallel to the axis of the mold (10), that the support elements inwardly towards one another are curved and are accordingly arranged adjacent to the inwardly curved side walls of the mold, and means adjacent the support members for spraying a liquid coolant against the curved ones Areas of the strand are arranged through the grid of the support elements. - 18 - 209835/0872 3 · Device according to claim 2, characterized in that each of the support elements consists of one Grid (45, 46) with spaced apart parallel rods (48; 6O, 61; 8o) extending to the axis of the mold and arranged at a distance from one another with these connected cross bars (49; 63, 64, 65), and that the cross bars are shaped so that they give the grid a curved course. 4. Apparatus according to claim 3, characterized in that the spaced parallel to each other arranged rods (60, 6l) have a substantial width and at intervals with holes (67, 68) for spraying of coolant are provided by the same against the strand. 5. Apparatus according to claim 2, characterized in that the support elements consist of substantially triangular metal plates (80), which with one edge substantially parallel to and adjacent are arranged at the outlet of the mold and that the plates have holes (8l) for spraying coolant through exhibit the strand. 6. A method for continuous casting, characterized in that molten metal to one Continuous strand with a thin rim of solidified metal and a core of molten metal Metal is poured and the edge zone across its width oppositely arranged concave curved surfaces and the curved surfaces are mechanically supported during casting in order to prevent breakage of the same. - 19 209 835/0872 7. A method for continuous casting, characterized in that hot molten metal in cast an upright tubular chill mold with a cooling system is used to produce an exiting strand with an outer edge zone made of solidified metal, which contains a molten metal core that the emerging strand is mechanically supported at points spaced around it and in the longitudinal direction while a coolant is sprayed on all sides of the strand to reinforce its edge zone, that the strand is grasped and continuously pushed downward along a mechanical guide path while it is kept sufficiently hot and plastic, essentially due to its own weight, to the mechanical Adapt leadership. 8. The method according to claim 7 *, characterized in that the strand when sliding down mechanically along a curved downward one Away and then in a horizontally extending transverse direction while the strand is sufficient is kept hot and plastic in order to move in the horizontally transverse direction due to its own weight Straighten the part and that the strand is progressively cut into specified lengths when it is in this manner is directed. 9. The method according to claim 7 »characterized in that the strand is subjected to a controlled cooling during the mechanical guidance in order to solidify the strand completely, that the strand is kept at a temperature in the range of 65O to HOO ⁰ C during the solidification and that the strand, while it is at this temperature, is cut off in certain lengths, - 20 209835/0872 2206806 10. The method according to claim 8, characterized in that the strand is completely solidified and has a temperature in the range from 650 to 1100 ⁰ C when it is cut in certain lengths. 11. The method according to claim 7 *, characterized in that the strand is detected between rollers which are driven in one direction to move the strand down along the mechanical guide path to push. 12. The method according to claim 8, characterized in that the strand is detected between rollers is and is driven in one direction to the strand on a mechanical guide having curved Way and then along the horizontally extending way-to-push 13 · Device for continuous casting of metal with a tubular mold with means for cooling the same and means around the mold with their ends in to arrange different heights, characterized in that spaced bars (117, 118) of a grid extending downward from the base of the mold to one cast by the mold Line (II6) to take up, to guide and to support, facilities (II9 »120) for spraying a liquid coolant through the rods (117 * H8) are provided on the strand, rollers (125, * 26) are arranged below the rods and are arranged relative to one another for receiving and gripping the strand and ffeß a device is provided for driving the rollers in one direction of rotation. - 21 - 209835/0872 14. The device according to claim 13, characterized in that it is provided with a tubular guide (132) is provided, which is below the rollers (125 * 126) arranged for receiving and guiding the strand (II6) and the tubular guide (132) penetrating means (I4o, 141, 142, 143) for spraying liquid Coolants are provided on the strand during its passage through the guide. 15. The device according to claim 14, characterized in that the tubular guide (132) partially is curved in the longitudinal direction, so that the cast strand of metal from a higher to a lower To guide level and at its lower end in a substantially rectilinear section for straightening the Strand ends so that the strand is straightened when it emerges from the guide. 16. The apparatus according to claim I5, characterized in that a cutting device (147) is adjacent is arranged at the outlet of the tubular guide (132), so that the strand can be cut off in certain lengths is. 17 · Device according to claim I5, characterized in that the tubular guide (132) consists of a housing with longitudinally extending, forked, section-wise Structure consists of a device (135 * 136) for assembling and disassembling the sections (133j 134) comprises the sections of the housing facilities (137 * 138) for guiding the cast strand (116) made of metal through the guide have that housing substantially larger cross-section than the cast strand and spray nozzles (I4o, 141, 142, 143) for spraying on of coolant on and around the strand penetrate the housing. 209835/0872 - 22 - l8. Device according to claim 13, characterized in that g e k e η η indicates that a replacement slab (I50) is available for commissioning the device is provided that the replacement slab (150) has a head part that fits into the base of the mold (151) and a lug (151a) for anchoring is attached to the head part, that a plurality of joint parts (154-157) one after the other on the headboard with the help of a flexible aligning resilient part (I58) is attached that the head part (151) and the hinge parts (154-157) in engagement with each other with complementarily extending surfaces (152, 153) for relative articulation to one another stand. 19 · Device according to claim 18, characterized in that the head part (I5I) of the replacement slab (150) is made of a metal of high thermal conductivity so that it can be quickly sprayed before metal casting can be cooled. 209835/0872 Blank page