METHOD FOR CONTINUOUS CASTING OF METAL STRIP USING MOMENTUM SHUTDOWN - Patent application

Abstract

A metal strip continuous casting method using momentum shunting, comprising the steps of: adjusting the position of a shunting device (2) to start up a double roll strip continuous casting equipment; forming a uniform sheet-shaped molten metal stream (4) having initial momentum after molten metal (3) flows through the shunting device; the sheet-shaped molten metal stream enters a molten pool (5) with a superheat of 50-100°C and an initial speed of 0.5-2 m / s, the shunting device and the molten pool being disposed at an interval; forming vortices in the molten pool adjacent to two chill roll surfaces and having a momentum stirring effect under the action of the initial speed of the molten metal; and completing solidification of the molten metal by the momentum stirring action of the vortices as the two chill rolls rotate. This method utilizes the kinetic energy of the molten metal to form a vortex that is adjacent to the roll surface of the cooling roll in the molten pool and has a momentum stirring effect, and can produce equiaxed crystals when the superheat reaches at most 50 to 100°C, and can further increase the ratio of equiaxed crystals to 100%, thereby making it possible to refine the crystal grains and improve segregation.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This disclosure claims priority to China Patent Application No. 202111554142.9, entitled "Method for Continuous Casting Metal Strip Using Momentum Diversion," filed with the China Patent Office on December 17, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to a method for continuous casting of metal strip using momentum splitting and has application in the technical field of continuous casting of metal strip. [Background technology]

[0003] The crystal grains with a relatively small difference in size in each direction are called equiaxed crystals, while the crystal grains with a relatively large difference in size in each direction are called columnar crystals. If the properties of the equiaxed crystals are uniform and the properties of the columnar crystals are directional, and if the metal material has a dense and uniform equiaxed crystal structure, the mechanical properties and engineering properties of the metal material can be improved.

[0004] Double roll strip continuous casting is a near net shape continuous casting technology, which can produce strip material with a thickness close to that of the finished product to realize the short-run production of metal strip, and the process greatly simplifies the production process and shortens the length of the production line, which not only reduces the investment in equipment and significantly reduces costs, but also saves energy and protects the environment, and has excellent market prospects. Double roll strip continuous casting uses two water-cooled rolls as moving crystallizers, and the arrangement of the caster can be divided into horizontal double roll strip continuous casting equipment in which the cooling rolls are arranged vertically, vertical double roll strip continuous casting equipment in which the cooling rolls are arranged horizontally, and inclined double roll strip continuous casting equipment in which the cooling rolls are arranged inclined, according to the direction of motion of the cast strip. In the prior art, in the horizontal double roll strip continuous casting process, the molten metal at the lower head enters the weld pool through a supply nozzle in a laminar flow manner; in the vertical double roll strip continuous casting process, the molten metal enters the weld pool through an immersed flow divider and various measures are taken to reduce the kinetic energy of the molten metal and suppress turbulence in the weld pool; and in the inclined double roll strip continuous casting process, the molten metal also enters the weld pool in a laminar flow manner.

[0005] Chinese Patent CN103464702A discloses a near net shape forming apparatus and a forming method thereof for sheet metal, the near net shape forming apparatus for sheet metal includes a pair of inclined cast rolls, the inside of which is water-cooled and rotated in opposite directions, and a molten metal diversion device is provided on one side of the lower cast roll, the molten metal is uniformly and flatly spread on the roll surface of the lower cast roll by the diversion device, and the molten metal then forms a molten pool between the upper and lower cast rolls, and the molten metal is further solidified and rolled to achieve the near net shape forming of sheet metal. In this patent, the molten metal is uniformly and flatly spread on the roll surface of the lower cast roll, so that a vortex having a momentum stirring effect cannot be formed.

[0006] US Patent US7604039B2 discloses a flow diverter, in which the molten steel in the ladle enters the intermediate vessel through a water inlet, then enters the flow diverter through a refractory device, and the bottom side of the flow diverter has multiple flow diverter outlets. The flow diverter nozzle of the flow diverter is immersed in the molten steel, and the flow rate of the molten steel at the flow diverter outlet is reduced as much as possible to reduce the undulations of the liquid surface and meniscus of the molten pool, and control the stabilization of the molten pool. Because the flow diverter has multiple flow diverter outlets, the axial flow of the molten steel is not uniform, which causes the temperature field distribution in the molten pool to be non-uniform, and the strip cracks. At the same time, the molten steel enters the relatively large molten pool slowly, and cannot form a vortex with momentum stirring effect. The temperature update rate of the molten steel is relatively slow, the temperature gradient in the molten pool is relatively large, the unidirectional growth conditions are sufficient, the solidification structure mainly consisting of columnar crystals is easily formed, and the crystal grains in the solid phase transition structure are also relatively coarse, so that a fine equiaxed crystal structure is obtained to meet the requirements for the mechanical properties of the strip product, and it is necessary to improve it through subsequent processes such as rolling deformation. If the proportion of equiaxed crystals in the cast strip solidification structure can be increased, the crystal grains can be refined, segregation can be improved, and the load of subsequent processes can be reduced.

[0007] Chinese Patent CN100493745C discloses a method for improving the equiaxed crystal ratio by double roll strip continuous casting, in which a mixture of argon gas and hydrogen gas is introduced into the molten steel during the casting process to reduce the oxygen partial pressure, thereby lowering the undercooling degree of the molten steel, changing the solidification conditions of the molten steel, and extending the contact time between the molten steel and the casting roll in the liquid state, thereby improving the heat conduction between the casting roll and the solidified material shell. This method can improve the surface quality of the sheet, and by controlling the ratio of the mixed gas, the solidification structure of the sheet can be further controlled to improve the proportion of equiaxed crystals in the sheet and refine the grains. The disadvantage of this method is that the equipment is more complicated and difficult to operate, and it is difficult to control the partial contact state between the mixed gas and the molten steel and the roll surface of the rotating casting roll in this method, which makes the heat conduction between the molten steel and the casting roll unstable, and thus makes the structure of the strip material non-uniform. Although this method can expand the equiaxed crystal region, it cannot obtain a sheet with a 100% equiaxed crystal structure.

[0008] Chinese patent CN102069167A discloses a method for producing equiaxed strip material of grain-oriented silicon steel plate by double roll strip continuous casting technology, which includes obtaining equiaxed grains by controlling important process parameters such as superheat of molten steel in the strip continuous casting process, contact arc length and contact time between molten steel in the molten pool and the roll surface of the casting roll. The defect of this method is that the superheat of molten steel needs to be controlled at 15-30°C, the temperature control range is narrower, which increases the difficulty of control, and the obtained equiaxed grain structure is still coarse. When poured to a certain extent, as the temperature of the molten steel in the ladle drops, the molten steel is likely to solidify in the intermediate vessel and the water inlet, or the solidified part is too long, which causes a rolling stop accident. Meanwhile, when the superheat is higher than the above temperature range, the stirring effect in the molten pool in this patent is not clear, which is unfavorable to the growth of equiaxed grains. The reason why the equiaxed strip is produced in this patent under the condition of 15-30°C is that the initial superheat is relatively low and the undercooling is relatively high, so the nucleation rate increases, and the increase in the nucleation rate is not large, so a coarser equiaxed grain structure is formed. As can be understood by those skilled in the art, when the superheat is higher than 50°C, the structure of the produced metal strip is considered to be a columnar grain structure rather than an equiaxed grain structure.

[0009] As can be seen from the above, the prior art does not suggest a technique for producing an equiaxed grain structure by fully utilizing the kinetic energy of the molten metal to form a vortex in the molten pool adjacent to the roll surface of the chill roll. On the contrary, in the prior art, in order to prevent the molten metal liquid entering the diverter from pulsating, the diverter nozzle is generally immersed in the metal liquid or a weak cross flow enters the diverter nozzle, and although an equiaxed grain structure can be produced, the superheat must be controlled to 30°C or less, and the produced equiaxed grain structure is relatively coarse. Therefore, the prior art requires a metal strip continuous casting method and equipment capable of producing 100% equiaxed grain structure at a higher superheat. Summary of the Invention [Problem to be solved by the invention]

[0010] The objective of the present application is to provide a method for continuous casting of metal strip using momentum splitting, which fully utilizes the kinetic energy of the molten metal to form a vortex in the molten pool adjacent to the roll surface of the chill roll and having a momentum stirring effect, thereby producing an equiaxed strip when the superheat reaches at most 50-100°C, and further increasing the proportion of equiaxed crystals in the solidification structure of the cast strip to 100%, thereby refining the crystal grains and improving segregation. [Means for solving the problem]

[0011] The present application relates to a method for continuous casting of metal strip using momentum splitting, (1) adjusting the position of the flow diverter and starting up the double roll strip continuous casting facility; (2) the molten metal enters a flow diverter and flows through the flow diverter to form a sheet-like molten metal stream having a uniform initial momentum in an axial direction; (3) a sheet-shaped molten metal stream enters the molten pool with a superheat of 50-100°C and an initial speed of 0.5-2 m / s, the diverter and the molten pool are spaced apart from each other, and the diverter is not in contact with the molten pool; (4) forming a vortex flow adjacent to the two chill roll surfaces in the molten pool and having a momentum stirring effect by the action of the initial velocity of the molten metal; and (5) completing solidification of the molten metal by the momentum stirring action of the vortex as the two chill rolls rotate to produce a metal strip, the solidification structure of which is a uniform and fine equiaxed crystal structure.

[0012] The double roll strip continuous casting equipment may be an inclined double roll strip continuous casting equipment, and may include an upper cooling roll and a lower cooling roll, the upper cooling roll and the lower cooling roll being disposed at an incline to form a roll gap therebetween, and the flow diverter is provided above the lower cooling roll. The flow diverter may include an inlet portion that opens upward for receiving molten metal, a vertical outlet portion connected to the inlet portion having a continuous strip outlet at its bottom for sending out a sheet-like molten metal stream, and a flow guide plate connected to one side of the vertical outlet portion for guiding the sheet-like molten metal stream to flow out. The length of the vertical outlet portion may be 3 to 10 times the thickness of the vertical outlet portion, the length of the flow guide plate may be 5 to 10 times the thickness of the vertical outlet portion, and the distance from an intersection of the flow guide plate and the vertical outlet portion to the bottom of the vertical outlet portion may be 1.5 to 3 times the thickness of the vertical outlet portion. The angle α between a connecting line between the outlet end point of the flow dividing device and the axis of the lower cooling roll and a vertical line may be 0 to 70°, the angle β between the connecting line between the axis of the two cooling rolls and a vertical line may be 30 to 90°, angle α<angle β, and the difference between angle γ between the plate surface of the flow guide plate and the horizontal line and angle α may be 0 to 5°.

[0013] The double roll strip continuous casting equipment may further be a vertical double roll strip continuous casting equipment, comprising a first cooling roll and a second cooling roll arranged horizontally, the first cooling roll and the second cooling roll being provided above a central symmetrical position with a flow diverter device provided therebetween, and a roll gap being formed therebetween. The flow diverter device may comprise an inlet portion opening upward for receiving molten metal, and a vertical outlet portion connected to the inlet portion, the vertical outlet portion having a continuous strip-shaped outlet at its bottom for delivering a sheet-shaped molten metal stream. The length of the vertical outlet portion may be 3 to 10 times the thickness of the vertical outlet portion. Effect of the Invention

[0014] The metal strip continuous casting method using momentum splitting according to the present invention uses a momentum splitting method, that is, a splitting device supplies a sheet-shaped molten metal stream with uniform initial momentum in the axial direction, and ensures that the momentum of the molten metal stream is relatively large when it enters the molten pool, and has obvious momentum stirring effect in the molten pool. The relatively high momentum stirring effect of the vortex in the molten pool promotes the formation of equiaxed grain structure, and an equiaxed grain strip can be produced at a superheat of 50-100°C, and 100% equiaxed grain structure can be formed. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram of a metal strip continuous casting facility according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view of the flow dividing device of the first embodiment. [Diagram 3] FIG. 2 is a cross-sectional view of the flow dividing device of the first embodiment. [Figure 4] 4 is a cross-sectional view taken along line AA in FIG. [Diagram 5] FIG. 2 is a schematic diagram showing momentum split and vortex flows in the molten pool in Example 1. [Figure 6] FIG. 1 is a schematic diagram of a metal strip continuous casting facility according to a second embodiment. [Figure 7] FIG. 11 is a perspective view of a flow dividing device according to a second embodiment. [Figure 8] FIG. 6 is a cross-sectional view of the flow dividing device of the second embodiment. [Figure 9] 9 is a cross-sectional view of FIG. 8 taken along line B-B. [Figure 10] FIG. 11 is a schematic diagram showing momentum split and vortex flows in the molten pool in Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] In order to make the objectives, technical solutions and advantages of the present application clearer, the embodiments of the present application are described in detail below with reference to the accompanying drawings, in which: unless conflicting, the embodiments and features of the embodiments of the present application can be arbitrarily combined with each other.

[0017] The present application relates to a method for continuous casting of metal strip using momentum splitting, (1) adjusting the position of the flow diverter and starting up the double roll strip continuous casting facility; (2) the molten metal enters the flow dividing device and flows through the flow dividing device to form a sheet-like molten metal flow having a uniform initial momentum in an axial direction, the axial direction of which is aligned with the axial direction of the double rolls; (3) a sheet-shaped molten metal stream enters the molten pool with a superheat of 50-100°C and an initial speed of 0.5-2 m / s, the diverter and the molten pool are spaced apart from each other, and the diverter is not in contact with the molten pool; (4) forming a vortex flow adjacent to the two chill roll surfaces in the molten pool and having a momentum stirring effect by the action of the initial velocity of the molten metal; and (5) completing solidification of the molten metal by the momentum stirring action of the vortex as the two chill rolls rotate to produce a metal strip, the solidification structure of which is a uniform and fine equiaxed crystal structure.

[0018] The momentum splitting method of the present application requires the molten metal to have a relatively large initial velocity, and ensures that the momentum entering the molten pool is relatively large, so that the momentum stirring effect in the molten pool is obvious, and the relatively high momentum stirring effect of the vortex in the molten pool promotes the formation of equiaxed crystal structure. The momentum stirring effect of the vortex contributes to strengthening the heat exchange between the molten metal and the cooling roll, contributing to uniforming the temperature of each part of the molten pool, reducing the temperature gradient, and improving the degree of supercooling and nucleation rate. The momentum stirring of the vortex can refine the crystal grains by breaking dendrites and inhibiting the formation and growth of columnar crystals, and the momentum stirring of the vortex can further improve segregation by making the components more uniform. The more the vortex growth is carried out, the better the effects of refining the solidification structure, improving the ratio of equiaxed crystals, and improving segregation. Such momentum stirring effect can realize the formation of equiaxed crystals at a superheat of 50 to 100 ° C, and can effectively prevent the clogging of the intermediate vessel and the water inlet. At the same time, since the sheet-shaped molten metal flow entering the molten pool is uniform and continuous, the vortex formed in the molten pool is maintained uniformly along the axial direction of the cooling roll, thereby achieving uniform solidification and improving surface quality.

[0019] <Example 1> As shown in FIGS. 1 to 5, the method for continuously casting metal strip using momentum splitting according to the present invention may be realized by a tilted double roll continuous strip casting facility, the method comprising: (1) adjusting the position of the flow diverter and starting up the double roll strip continuous casting facility; (2) the molten metal enters a flow diverter and flows through the flow diverter to form a sheet-like molten metal stream having a uniform initial momentum in an axial direction; (3) the molten metal is introduced into a molten pool formed by two cooling rolls and two side seals along the roll surface of the lower roll at a superheat of 50-100°C and an initial speed of 0.5-2 m / s, the diverter and the molten pool are spaced apart from each other, and the diverter is not in contact with the molten pool; (4) forming a vortex flow adjacent to the two chill roll surfaces in the molten pool and having a momentum stirring effect by the action of the initial velocity of the molten metal; and (5) completing solidification of the molten metal by the momentum stirring action of the vortex as the two chill rolls rotate to produce a metal strip, the solidification structure of which is a uniform and fine equiaxed crystal structure.

[0020] As shown in Figures 1 to 4, the inclined double roll strip continuous casting equipment includes a first cooling roll 1 located below and a second cooling roll 6 located above, the first cooling roll 1 and the second cooling roll 6 are arranged at an incline and a roll gap is formed between them, a flow diverter 2 is provided above the first cooling roll 1, and the molten metal 3 flows out of the flow diverter 2 to form a sheet-like molten metal flow 4 that is uniform in the axial direction and has an initial momentum. The angle α between the connecting line between the outlet end point of the flow diverter 2 and the axis of the lower roll and the vertical line is 0 to 70°, preferably 20 to 60°, for example, it may be 40°, the angle β between the connecting line between the axis centers of the two cooling rolls and the vertical line is 30 to 90°, preferably 60 to 80°, for example, it may be 70°, and the angle α is smaller than the angle β. The initial momentum can be adjusted by the liquid level height of the intermediate vessel or chute and the height between the flow diverters, and the flow diverter is not in contact with the molten pool to ensure sufficient growth of the vortex. The sheet-like molten metal flow enters the roll gap between the first and second cooling rolls 1 and 6 along the roll surface of the first cooling roll at an initial speed of 0.5-2 m / s to form a molten pool 5, and the sheet-like molten metal flow then forms a vortex momentum in the molten pool 5. The first and second cooling rolls 1 and 6 rotate synchronously in opposite directions, and the roll speed may be 0.1-3 m / s. The solidification of the molten metal is completed by the momentum stirring action of the vortex, and the produced metal strip 7 is pulled out from the roll gap between the first and second cooling rolls 1 and 6, and the solidification structure of the metal strip 7 is a uniform and fine equiaxed crystal structure.

[0021] The flow dividing device 2 includes an inlet section 8 that opens upward for receiving molten metal from the intermediate vessel, a vertical outlet section 9 that is connected to the inlet section 8 and has a continuous strip-shaped outlet at its bottom for delivering the sheet-shaped molten metal flow, and a flow guide plate 10 that is connected to one side of the vertical outlet section 9 for guiding the outflow direction of the sheet-shaped molten metal flow. 1 is the thickness t of the vertical outlet part 9 1 The length of the flow guide plate 10 is 3 to 10 times, preferably 5 to 7 times, 2 is the thickness t of the vertical outlet part 9 1 The distance b from the intersection of the flow guide plate 10 and the vertical outlet portion 9 to the bottom of the vertical outlet portion 9 is 5 to 10 times, preferably 7 to 8 times, the thickness t of the vertical outlet portion 9. 1 The angle γ between the plate surface of the flow guide plate 10 and the horizontal line is γ=α+δ, where δ is the amount of angular deviation between α and γ and may be 0 to 5°. By setting the above dimensional and angular relationships in combination, it is possible to make the sheet-shaped molten metal flow that has flowed onto the roll surface along the flow guide plate produce a good momentum stirring effect in the molten pool, thereby realizing vortex stirring required for producing 100% equiaxed grains.

[0022] In the comparative example, the molten metal enters the molten pool space along the roll surface of the lower roll with a superheat of 70°C and an initial speed of 1 m / s, and forms vortexes in the molten pool adjacent to the two cooling roll surfaces and having momentum stirring action. The momentum stirring action of the vortexes completes the solidification of the molten metal to produce a metal strip, whose solidification structure is a uniform and fine 100% equiaxed crystal structure with a grain size of 80 μm.

[0023] <Example 2> As shown in Figures 6 to 10, the method for continuous casting of metal strip using momentum splitting according to the present application may further be realized by a vertical double roll continuous strip casting equipment, the method comprising: (1) adjusting the position of the flow diverter and starting up the double roll strip continuous casting facility; (2) the molten metal enters the flow diverter through an intermediate vessel or chute and flows through the flow diverter to form a sheet-like molten metal stream having a uniform initial momentum in an axial direction; (3) the molten metal enters the molten pool formed by the two chill rolls and the two side seals along the symmetrical plane of the adjacent roll faces of the two chill rolls with a superheat of 50-100°C and an initial speed of 0.5-2 m / s, and the flow dividing device and the molten pool are spaced apart; (4) forming a vortex flow adjacent to the two chill roll surfaces in the molten pool and having a momentum stirring effect by the action of the initial velocity of the molten metal; and (5) completing solidification of the molten metal by the momentum stirring action of the vortex as the two chill rolls rotate to produce a metal strip, the solidification structure of which is a uniform and fine equiaxed crystal structure.

[0024] As shown in Figures 7 to 9, the vertical double-roll strip continuous casting equipment includes a first cooling roll 11 and a second cooling roll 16 arranged horizontally, with a roll gap formed therebetween, and a flow diverter 12 is provided above the symmetrical positions of the first cooling roll 11 and the second cooling roll 16, and molten metal 13 flows out of the flow diverter 12 to form a sheet-like molten metal stream 14 that is uniform in the axial direction and has an initial momentum. The flow diverter 12 includes an inlet portion 18 that opens upward for receiving molten metal from an intermediate vessel or chute, and a vertical outlet portion 19 connected to the inlet portion 18, the bottom of which is provided with a continuous strip-like outlet for delivering the sheet-like molten metal stream 14. The length l of the vertical outlet portion 19 is 10 mm. 3 is the thickness t of the vertical outlet part 19 2The initial speed of the sheet-like molten metal stream 14 is 0.5-2 m / s and enters the roll gap between the first and second cooling rolls 11 and 16 to form a molten pool 15, and the sheet-like molten metal stream 14 subsequently forms a vortex momentum in the molten pool 15. The first and second cooling rolls 11 and 16 rotate synchronously in opposite directions, and the roll speed may be 0.1-3 m / s. The vortex momentum stirring action completes the solidification of the molten metal, and the produced metal strip 17 is pulled out from the roll gap between the first and second cooling rolls 11 and 16, and the solidification structure of the metal strip 17 is a uniform and fine equiaxed crystal structure.

[0025] In the comparative example, the molten metal enters the molten pool space from the center position above the two chill rolls with a superheat of 60°C and an initial speed of 0.8 m / s, and forms vortexes in the molten pool adjacent to the two chill roll surfaces and having a momentum stirring effect. The momentum stirring effect of the vortexes completes the solidification of the molten metal to produce a metal strip, whose solidification structure is a uniform and fine 100% equiaxed crystal structure with a grain size of 100 μm.

[0026] The metal strip continuous casting method according to the present invention is easy to operate, and under the premise of not changing the original material composition and not reducing the superheat, it is possible to improve the proportion of equiaxed crystals in the solidification structure of the metal strip, and the proportion of equiaxed crystals can reach at most 100%, thereby refining the crystal grains and improving segregation. The present invention may be used for near-net-shape continuous casting of various metal strips such as steel and non-ferrous metals.

[0027] The above are the embodiments disclosed in the present application, but the above contents are merely embodiments used to facilitate understanding of the present application, and are not intended to limit the present application. Those skilled in the art may arbitrarily modify and change the implementation form and details without departing from the spirit and scope disclosed in the present application, but the patent protection scope of the present application should still conform to the scope limited by the appended claims.

Claims

1. 1. A method for continuous casting of metal strip using momentum splitting, comprising the steps of: (1) adjusting the position of the flow diverter and starting up the double roll strip continuous casting equipment; (2) forming a sheet-like molten metal stream having a uniform initial momentum in an axial direction after the molten metal enters a flow diverter and flows through the flow diverter; (3) a sheet-shaped molten metal stream enters the molten pool with a superheat of 50-100°C and an initial speed of 0.5-2 m / s, the diverter and the molten pool are spaced apart from each other, and the diverter is not in contact with the molten pool; (4) forming vortices (referred to as "momentum-stirring vortices") in the molten pool adjacent to the two chill roll surfaces under the effect of the initial velocity of the molten metal; and and (5) completing solidification of the molten metal by the action of momentum-agitating vortexes as the two chill rolls rotate to produce a metal strip, the solidification structure of which is a uniform and fine equiaxed crystal structure.

2. 2. The method for continuous casting of metal strip according to claim 1, wherein the double-roll strip continuous casting equipment is an inclined double-roll strip continuous casting equipment, comprising an upper chill roll and a lower chill roll, the upper chill roll and the lower chill roll are arranged at an incline to form a roll gap therebetween, and the flow diverter is provided above the lower chill roll.

3. The flow dividing device is an upwardly opening inlet portion for receiving molten metal; a vertical outlet section extending downwardly from the inlet section, the vertical outlet section being of generally constant thickness and having a continuous strip-like outlet at a bottom thereof for forming a sheet-like molten metal stream; 3. The method of claim 2, further comprising: a flow guide plate connected to one side of said vertical outlet portion for guiding the sheet-like molten metal stream toward said lower chill roll.

4. 4. The method for continuous casting of metal strip as claimed in claim 3, characterized in that the length (l1) of the vertical outlet portion is 3 to 10 times the thickness (t1) of the vertical outlet portion, the length (l2) of the baffle plate is 5 to 10 times the thickness (t1) of the vertical outlet portion, and the distance (b) from the intersection of the baffle plate and the vertical outlet portion to the bottom of the vertical outlet portion is 1.5 to 3 times the thickness (t1) of the vertical outlet portion.

5. 5. A method for continuous casting of metal strip as claimed in claim 4, characterized in that the length (l1) of the vertical outlet portion is 5 to 7 times the thickness (t1) of the vertical outlet portion, the length (l2) of the baffle plate is 7 to 8 times the thickness (t1) of the vertical outlet portion, and the distance (b) from the intersection of the baffle plate and the vertical outlet portion to the bottom of the vertical outlet portion is 2 to 2.5 times the thickness (t1) of the vertical outlet portion.

6. 6. A method for continuous casting of metal strip as claimed in claim 4 or 5, characterized in that an angle α formed by a connecting line between an outlet end point of the flow guide plate of the flow dividing device and an axis of the lower cooling roll and a vertical line is 0 to 70°, an angle β formed by a connecting line between the axis of the two cooling rolls and a vertical line is 30 to 90°, angle α < angle β, and a difference between angle γ formed by the plate surface of the flow guide plate and a horizontal line and angle α is 0 to 5°.

7. 7. The method for continuous casting of metal strip according to claim 6, characterized in that the angle α between a connecting line between the outlet end point of the flow guide plate of the flow dividing device and the axis of the lower cooling roll and a vertical line is 20 to 60°, the angle β between the connecting line between the axis of the two cooling rolls and a vertical line is 60 to 80°, angle α < angle β, and the difference between angle γ between the plate surface of the flow guide plate and a horizontal line and angle α is 0 to 5°.

8. 2. The method for continuous casting of metal strip according to claim 1, wherein the double roll strip continuous casting equipment is a vertical double roll strip continuous casting equipment, and includes a first chill roll and a second chill roll which are arranged horizontally, and a flow dividing device is provided above the first chill roll and the second chill roll at a central symmetrical position, and a roll gap is formed between them.

9. The flow dividing device is an upwardly opening inlet portion for receiving molten metal; 9. The method of claim 8, further comprising: a vertical outlet section extending downwardly from said inlet section, said vertical outlet section being of substantially constant thickness and having a continuous strip outlet at its bottom for delivering a sheet-like stream of molten metal.

10. A method as claimed in claim 9, characterized in that the length (l3) of said vertical outlet section is between 3 and 10 times the thickness (t2) of said vertical outlet section.

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