Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/12—Accessories for subsequent treating or working cast stock in situ
  • B22D11/1206—Accessories for subsequent treating or working cast stock in situ for plastic shaping of strands
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
  • B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
  • B21B1/463—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a continuous process, i.e. the cast not being cut before rolling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/14—Plants for continuous casting
  • B22D11/142—Plants for continuous casting for curved casting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
  • B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
  • B21B1/24—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a continuous or semi-continuous process
  • B21B1/26—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a continuous or semi-continuous process by hot-rolling, e.g. Steckel hot mill
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B31/00—Rolling stand structures; Mounting, adjusting, or interchanging rolls, roll mountings, or stand frames
  • B21B31/02—Rolling stand frames or housings; Roll mountings ; Roll chocks
  • B21B2031/025—Shifting the stand in or against the rolling direction
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B2201/00—Special rolling modes
  • B21B2201/14—Soft reduction
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B2201/00—Special rolling modes
  • B21B2201/18—Vertical rolling pass lines
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B39/00—Arrangements for moving, supporting, or positioning work, or controlling its movement, combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
  • B21B39/006—Pinch roll sets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
  • B21B45/04—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing
  • B21B45/08—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing hydraulically

Definitions

• This invention refers to a process and related plant for the production of metal strip using thin slabs produced by a mold. State of the art
• a strip production process envisages first of all prerolling of the slab with the core still liquid, that is to say the so-called soft reduction, immediately at the outfeed of the mold.
• the slab whose size and thickness are already close to that of a strip, is then deviated from a transport trajectory towards a horizontal trajectory along which it passes through a set of successive millstands to bring its thickness to the desired value, for example such as to permit winding in rolls.
• the slab at the out- feed of a mold is still very thick, in relation to the final thickness to be obtained at the end of the production line, numerous millstands are required.
• a heating furnace is always present, ahead of the mill train, that increases the temperature of the slab so that, along the train, the temperature of the material never drops below the recrystallization point Ar 3 , and so that rolling always takes place in the austenitic range.
• Plants of the known art also envisage inter-stand inductors to heat the strip being rolled, also to guarantee that austenitic steel is obtained.
• the metal strip production plants tend to be very long because the slabs produced by the known type molds, also called crystallizers, are very thick at the outfeed of the mold; as a result the plant must comprise numerous intermediate devices that considerably increase its total length.
• Considerable efforts have been dedicated to constructing molds able to produce thinner slabs in order to reduce the number of thickness reduction millstands along the strip production line with the advantage of reducing the overall length of the line and strip production energy costs.
• the minimum outfeed thickness of the slab that can be produced is between 50 and 60 mm.
• the main aim of this invention is to construct an ultra-compact plant with related process for continuous production of hot-rolled steel strip from extra-thin slabs obtained through high speed continuous casting.
• Another purpose of the invention is that of obtaining a hot-rolled strip, with a thickness of between 1 ,5 to 5 mm, having a fine grain structure distributed so regularly as to al- ready possess the characteristics of a high quality cold-rolled material.
• a further purpose is to construct a high throughput endless plant that reduces investments and operating costs compared with a conventional plant to produce the same strip thickness values.
• the slabs, produced using an innovative mold are of very reduced thickness, be- tween 25 and 32 mm, preferably 28 mm and are characterized at the same time by a still liquid core on exiting from the mold, such as to permit advantageous further reduction of thickness to 22 mm.
• accurate dimensioning of the parts of the casting chamber of a mold is such as to guarantee a suitable space so that the jets of liquid steel from the discharge nozzle do not give rise to the undesirable phenomenon of remelting of the skin that forms inside its inner surface, especially at a certain distance from the discharge nozzle where the area of the section of the jet is higher.
• this invention proposes to solve the foregoing problems and to achieve the aforesaid purposes, defining a hot-rolled metal strip production process wherein there is provided a mold, a soft reduction device located close to the outfeed section of a mold, a first rolling device, a path rerouting device at least during predetermined periods of time, at least a horizontal pulling device, a descaling device and one or more rolling stands arranged in a compact group, the process including the following stages: a) casting a thin slab with exit from a mold at a speed of between 6 and 16 m/min, having the narrow sides between 25 and 32 mm, and a core in which the steel is liquid, b) soft reducing the slab using said soft reduction device, c) performing a first rolling operation on the solidified slab to obtain a presthp using such first rolling device, d) performing an operation of scale removal on the prestrip using said descaling device, performing a plurality of further rolling operations using said one or more millstands on the prestrip, obtaining
• Hot-rolled metal strip production plant including a mold, soft reduction device located close to the outfeed section of a mold, a first rolling device suitable to produce a prestrip, a rerouting device which can be activated at least during pre-established periods of time from a vertical trajectory to a horizontal trajectory, at least a horizontal pulling device, a descaling device and one or more rolling stands arranged in a compact group, wherein the plane of the infeed section of the mold is arranged at a height from the horizontal trajectory of less than 7 m and a first one of the one or more rolling stands (20', 20", 20'") is arranged at a distance less than 6 m from the vertical extrados plane of the mold.
• an ultra-thin slab is cast of a thickness that is much lower than that which can be obtained with known molds, in the range 25 and 32 mm, as indicated above, and in which the core remains liquid also in the zones closest to the side parts. Therefore, the entire slab can subsequently undergo soft reduction obtaining, advantageously, refining of the structure of the core that is solidifying, with reduction of internal porosity and elimination of the phenomenon of central segregation.
• a first solidified core or hard reduction is performed as thickness is reduced with the product still rather hot, low rolling forces are required, with simplification of the millstand, for example a tandem stand, with reduction of costs and also of dimensions; advantageously, such stand also performs the function of puller;
• the product is in hybrid slab/strip form but is in any case very thin and still at a high enough temperature to endow the product with sufficient ductility that it can form a loop when passing from the vertical direction, of casting, to the horizontal direction of rolling.
• soft reduction is carried out in a controlled manner so as to permit suitable management of the closing point of the liquid cone also during transitory phases tied to variations that may take place in casting parameters in relation to on- stream working conditions. This guarantees constantly excellent quality of the slab in all working conditions.
• the liquid cone is closed advantageously in the section between the outfeed section from the mold and the center distance between the first rollers underneath; rolling is therefore performed on the completely solidified product, downstream of or at the limit position of the "kissing point".
• Such first rolling provides a further contribution to quality, in particular internal, of the product as it closes the interdendritic paths between grains through compacting of the structure.
• the first rolls also act as pinch rolls for the thin slab.
• the high speed of product casting in the form of ultra-thin slab and direct connection with the mill train which transform it from slab to strip starting from a lower thickness than that of known casting processes and also the compact design of the plant guarantee that the product is always in the austenitic range during hot rolling.
• compact arrangement of the millstands does not require the presence of a heating furnace ahead of the mill train and of inductors located in an intermediate position between the millstands in order to raise the temperature of the product processed. In this way, at the end of the first part of the production line, the strip has been reduced to a thickness of between 1 ,5 and 3 mm in less space, with reduced consumption of energy and lower plant costs in that fewer millstands are required and installation of heating furnaces is also avoided.
• Fig. 1 shows a longitudinal section of the plant of the invention
• Fig. 2 shows a 3D view of a first embodiment of a component of the plant of Fig. 1 ;
• Fig. 3a shows a section along the plane y-z of the component of Fig. 2;
• Fig. 3b shows a plan view of the component of Fig. 2
• Fig. 4a shows a section along the plane y-z of another embodiment of the component of Fig. 2;
• Fig. 4b shows a plan view of the embodiment of the component of Fig. 4a
• Fig. 5 shows an enlargement of a detail of the component of Fig. 2
• Fig. 6 shows a 3D view of another embodiment of a component of the plant of the invention
• Fig. 7a shows a section along the plane y-z of the component of Fig. 6
• Fig. 7b shows a plan view of the component of Fig. 6
• Fig. 8a shows a section along the plane y-z of an embodiment of the component of Fig. 6;
• Fig. 8b shows a plan view of the embodiment of the component of Fig. 8a;
• Fig. 9 shows an enlargement of a detail of the plan view of Fig. 7b.
• a metal strip production plant including the following is shown:
• the mold 15 produces a very thin slab, with thickness of the narrow walls of between 25 and 32 mm, with a central bulge and a core in which the steel is still liquid.
• a first embodiment of a mold is shown, with a longitudinal plane of sym- metry X parallel to the reference axes x-z, and a transversal plane of symmetry Y parallel to the reference axes y-z, including two wide plates 1 , 2 that, coupled together, define a through cavity 3 or casting chamber.
• the surface of such cavity is defined by two wide walls 4, 5, reciprocally arranged so that they face onto opposite sides in relation to the plane of symmetry X, and by two narrow walls 6, 7 generally flat, rectangular and parallel, arranged horizontally to the plane of symmetry X.
• the wide and narrow walls form four longitudinal edges in the zones where they are joined.
• the wide walls 4, 5 are concave with the concave area facing towards the longitudinal plane of symmetry X.
• the concave area of the walls 4, 5 is such as to define a lenticular shaped section of the casting chamber.
• - T is between 750 and 2000 mm;
• - "f" is between 15 and 100 mm.
• such mold or lenticular crystallizer, ensures that the corners are not affected by excessive pivoting during prerolling, avoiding the appearance of cracks or other defects in these zones.
• the lenticular shape makes it possible to maintain the core liquid also very close to the end sides of the slab and therefore permits subsequent soft reduction of the entire slab cast. Also, the volume of liquid steel in the mold is sufficient to dampen the fluid-dynamic turbulence generated by the discharge nozzle.
• a first advantageous variant of this first embodiment of the mold provides a steel in- feed section larger than the outfeed section close to the lower end of the mold.
• the radius of curvature of the circumference arc on the transversal plane has a value that increases in linear fashion between the infeed section and a predefined intermediate section that corresponds to the terminal section of the casting chamber, before the outfeed section of the steel.
• such mold envisages a slope of the wide walls of such casting chamber 3, converging towards such intermediate section defined by an angle a of between 0°and 7° such angle a being measured as a slope in relation to the plane X and in projection on the plane of symmetry Y.
• a second variant of the first embodiment of the mold envisages infeed and exit sections of the mold of the same size, as illustrated in the section of Fig. 4a.
• the radius of curvature of the circumference arc on the transver- sal plane has the same value at each point of the longitudinal extension of the cavity between the infeed section and outfeed section of the steel.
• a second embodiment of the mold of the plant of the invention is represented, also with a longitudinal plane of symmetry X parallel to the reference axes x-z, and a transversal plane of symmetry Y parallel to the reference axes y-z.
• This mold has a casting chamber or through cavity 3' whose surface is defined by two plates 1 ', 2' with wide walls 4', 5', arranged reciprocally as facing on opposite sides in relation to the plane of symmetry X and by two elements or narrow walls 6', T reciprocally parallel and placed between such wide walls, and arranged orthogonally to the plane of symmetry X.
• the walls 4', 5', 6', T form four longitudinal corners in the zone where they are joined.
• the wide walls 4', 5' of the plates 1 ', 2' are characterized, unlike the first embodiment, by a double curve, one concave and one convex, facing towards the longitudi- nal plane of symmetry X.
• each of the wide walls 4', 5' includes:
• connection zones 13 having convex surfaces, between the circumference arc of the central zone 11 and the side zones 12, with the convexity facing towards the plane of symmetry X.
• the point P is the point of intersection of the straight section R of the flat zone of the walls with convex joining section S;
• the point P' is the point at which the concave area of the wide plate 2' also known as point of inflection changes;
• the point P" is the point of intersection of the concave zone 11 with the transversal plane of symmetry Y parallel to the reference axes y and z. At this point, the following values are defined:
• - length "d" is the distance between the point P and the point P' measured in projection on the plane of symmetry X parallel to the reference axes x and z;
• I is the distance between the point P and its symmetrical in relation to the plane Y measured in projection on the plane of symmetry X;
• I/2 is there- fore the distance between the point P and the point P", of maximum concavity, measured in projection on the plane of symmetry X;
• - height "h” is the distance between the point P and the point P' measured in projection on the plane of symmetry Y;
• this mold has the following values at the infeed section:
• - I is between 750 and 1500 mm;
• - f is between 15 and 100 mm. Furthermore, also in the infeed section, the relationship d/l and the relationship h/f are between 10% and 60%.
• a first advantageous variant of this second embodiment of the mold provides a casting chamber 3' with an infeed section of the steel larger than the outfeed section.
• the value of the radius of curvature of the concave zone 11 when this has the shape a circumference arc, on the transversal plane, increases linearily between the infeed section and an intermediate section that corresponds to the terminal section of the casting chamber, before the outfeed section of the steel; the value of the radius of curvature of the connection zone 13 decreases linearily between the infeed section and such intermediate section.
• such cavity or casting chamber 3' passes through in a longitudinal direction with generating lines converging towards the exit as far as the intermediate section.
• a cone-shaped narrowing is visible.
• deflection f has a maximum value in the infeed section of the mold and a minimum value at the outfeed section of the casting chamber.
• such mold envisages a slope of the wide walls of such chamber converging towards such intermediate section, defined by an angle a of between 0° and 7° such angle a being measured as a slope in relation to the plane X and in pro- jection on the plane of symmetry Y.
• this particular configuration of the casting chamber allows the liquid steel to come into contact with the side zones 12 with flat faces, as far as the edges, and therefore prevents complete solidification of the slab in such zone despite a lower distance between such faces compared with that of the known art.
• Below such intermediate section of the mold there is a final section 10', not sloping and with parallel generating lines of pre-established length that is geometrically the same as such intermediate section and permits insertion and extraction of the shaped head of the dummy bar used to start casting.
• the reduced slope of the wide walls 4', 5' of the casting chamber defined by the angle a makes it possible to avoid the undesirable phenomenon of remelting of the skin formed as the liquid steel poured into the chamber by the discharge nozzle does not cause turbulence in the zone of feeding of the mold close to the walls, guaranteeing optimal flow of the discharged steel .
• the narrow walls 6', T preferably flat and rectangular, are advantageously mobile and able to move close to or retract from each other permitting adjustment of the width of the slab. They can also modify their taper that is to say more precisely, they can be more inclined towards the inside close to the outfeed section of the steel so as to reduce the width of the outfeed section, making it possible in this way to avoid problems tied to shrinkage during solidification in the mold.
• a second variant of the second embodiment of the mold of the plant of the invention envisages, on the other hand, infeed and exit sections of the same size, as illustrated in the section of Fig. 8a.
• the radii of curvature maintain the same value at each point of the longitudinal extension of the casting chamber between the infeed section and the outfeed section of the steel.
• the aforesaid intermediate section coincides with the outfeed section of the steel.
• the geometry of the mold in any of the aforementioned four variants, guarantees a suitable volume of liquid steel in the mold so that, at the outfeed from this, the slab still has an appropriately-sized liquid core.
• the particular shape makes it possible to maintain the core liquid also very close to the end sides of the slab. In this way, soft reduction will be carried out successfully.
• the presence of liquid steel in the side zones and the fact that in such narrow zones complete solidification has not occurred prevents occurrence of undesirable cracks and guarantees effective melting of the lubrication powders.
• a thin slab with a thickness of between 20 and 50 mm is cast at a speed of between 6 and 16 m/min.
• a prerolling device 16 including a rollerbed or set of idle transversal rollers 16' shaped so as to modify the transit sec- tion of the slab and to perform a gradual action of flattening of the convex or bulging surface, as on exiting from the crystallizer, so as to bring the slab to a rectangular section.
• Such action of recovery of the swelling involves compression of the slab with liquid core until a thickness equal to the width of the narrow sides of the outfeed section of the mold is reached.
• rollers 16' can be located at a closer distance so as to obtain, on exit from the rollerbed, a slab of lower thickness compared with that exiting from the crystallizer, and also linearized: basically a reduction of thickness is carried out on a slab that still has a liquid core, i.e. soft reduction.
• the slab has been reduced to a thickness of between 10 and 25 mm.
• soft reduction acts in a controlled manner (dynamic soft reduction) so as to permit correct control of the closing point of the liquid cone also during transitory periods tied to possible variations in the casting parameters in relation to on- stream working conditions. This guarantees constantly excellent quality of the slab in all working conditions.
• the set of rollers 16' cooperates with an integrated direct cooling system and also performs the function of containing and guiding the slab.
• a first rolling device 17 including two cylinders 17', 17" that perform the double function of extracting the slab from the mold and of further reducing its thickness applying a suitable flattening force on this. More particularly, such cylinders 17', 17" flatten the slab downstream or, at the most, at the position of the closing point of the liquid cone, also known as kissing point; in this way the cylinders 17', 17" perform their action on the completely solidified slab and then performing an effective rolling operation also called hard reduction.
• a rerouting device 18 is provided that includes a curved opening rollerbed located immediately below the two cylinders 17', 17". The curved rollerbed 18, 18' is also necessary to permit guidance and insertion of the head of the dummy bar inside the mold.
• the slab pulled by the dummy bar does not have a liquid core so its thickness cannot be reduced through soft reduction and the two cylinders 17', 17" do not exert their action. Therefore, the first section of slab cast has a thickness equal to that on exit from mold along the entire line as far as the entrance of the millstand 20', and in this first short phase is defined by convention as "thick" slab.
• the curved rollerbed 18, 18' is scaled so that it can apply sufficient force to bend the "thick" slab.
• the guide rollers 23 of the curved rollerbed 18, 18' are idle and the support of the rollerbed is maintained in the active position by suitable hydraulic jacks 21 , 21 '.
• Both the lower part 18 and the upper part 18' of the rollerbed are hinged so that they can be rotated when it is necessary to free the trajectory followed by the prestrip in steady state operating conditions and when, in emergency conditions such as for example jamming, it is necessary to unload all the material in the pit.
• the positions of the rollerbed 18, 18' free of the strip are shown with thin lines in figure 1.
• casting is carried out at duty cycle and the two parts 18, 18' of the rollerbed are in the open position allowing the prestrip to form a loop of variable length (not illustrated), i.e. a path that first of all descends and then returns up and ascends before following the horizontal path.
• the presence along the casting line of a loop permits various advantages: a) that of decoupling the rolling train from casting and of managing any changes in speed between the millstands and the mold; b) that of reducing cooling of the prestrip as there is less heat exchange between the support and guide rollers.
• a) that of decoupling the rolling train from casting and of managing any changes in speed between the millstands and the mold b) that of reducing cooling of the prestrip as there is less heat exchange between the support and guide rollers.
• the function of the pair of pinch rolls 22', 22" is to pull the "thick" slab in the initial transitory phase and the prestrip after start-up.
• Pinch roll 22' arranged further ahead, has the roller 25 of larger diameter in order to: a) straighten the point of the "thick" slab in the starting phase and b) provide a suitable supporting surface for the loop formed by the prestrip during the on-stream process.
• millstands Downstream of the descaling device 19, there are three millstands, for example of the four type, of limited pitch, that is to say having a center distance of less than 1600 mm, forming a compact group. Ahead of the first stand, there is a water type rotating scale remover 19.
• the fact that the millstands are close to each other makes it possible to reduce losses of heat of the material when passing from one stand to the next and to bring it out of the train at a temperature that is still above 850 °C. Therefore, the advantage inherent in this compact arrangement of the millstands 20', 20", 20'" is that of maintaining the temperature of the strip being rolled above the re- crystallization point Ar 3 , thus avoiding the need for heating furnaces ahead of the train. Furthermore, this is also made possible because losses of heat of the prestrip along the path are reduced.
• the end millstands are fitted on rails 26 and can be moved using hydraulic jacks 27', 27" so as to open the compact group and to take action in the case of jamming of the strip.
• the scale remover is advantageously fitted on a carriage 28 so that it can be traversed in relation to the rolling line in order to create the space necessary to open the millstands.
• the plane of the infeed section of the mold is at a height in relation to the horizontal rolling line of less than 7 m, preferably between 4,0 and 6,5 m.
• the length of the casting machine, as far as the end of the curved deviation section, is therefore lower than in plants of the known art.
• the strip undergoes laminar cooling with water, is cut to size using shears and is wound in rolls of a weight of around 30 tons on at least one reel, preferably two.
• the plant according to this invention it is possible to obtain the finished product in a very reduced space.
• casting of very thin slabs using the mold 15, in its vari- ous embodiments makes it possible to cast an initial product, that is to say the slab, at high speed and already with a thickness very close to that of the finished product, i.e. the strip.
• the thin slabs obtained have a thickness at the outfeed of between 25 and 32 mm, with a casting speed of between 6 and 16 m/min. All this promotes a considerable reduction in the number of machines of the plant involved in the plant/process which results in a considerable saving in initial investment and energy costs and of the waster used in the cooling systems.
• a preferred embodiment of the plant of the invention is provided with a height of the casting plane in relation to the horizontal plane of the strip in the millstands 20', 20", 20'" equal to around 4,0 m.
• the distance between the plane of the infeed section of the mold and the centre distance of the cylinders 17', 17" of the first rolling device 17 is equal to around 2,6 m; and the distance between the height of the meniscus inside the mold and the closing point of the liquid cone, or kissing point, inside the slab during prerolling is around 2,8 m at a casting speed of 10 m/min and around 1 ,6 m at a speed of 8 m/min.
• the first stand 20' of the millstands 20', 20", 20'" is arranged at a distance from the vertical extrados plane of the mold of less than 6 m, preferably 4,5 m, with a minimum distance between such first stand and the scale remover 19 equal to around 2,5 m.
• the prestrip arrives advantageously at the first stand 20' at high temperature, at least equal to 1170°C, and with a feed speed equal to the casting speed, without interruptions on the production line.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Metal Rolling (AREA)
• Continuous Casting (AREA)
• Superconductors And Manufacturing Methods Therefor (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=36218805

Family Applications (1)

Country Status (4)

Cited By (3)

Families Citing this family (2)

Citations (6)

• 2005
  • 2005-09-22 IT IT001764A patent/ITMI20051764A1/it unknown
• 2006
  • 2006-09-22 AT AT06793735T patent/ATE549101T1/de active
  • 2006-09-22 EP EP06793735A patent/EP1940566B1/de not_active Revoked
  • 2006-09-22 WO PCT/EP2006/066615 patent/WO2007039483A1/en active Application Filing

Patent Citations (6)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events