Roll gap floating method for double-roll thin strip

Abstract

The invention provides a roll gap floating method for a double-roll thin strip, namely roll gap fixed opening-synchronous floating, and belongs to the technical field of double-roll thin strips. In the preparation process, the roll gap floating process and the roll system movement process are controlled to simultaneously and synchronously occur, and the change of the roll gap floating process to the placement plane and the change of the roll system movement process to the placement plane are all offset in real time, so that the two roll bodies are always kept static to the ground. Compared with the prior art, the technical scheme provided by the invention has the advantages that in the roll gap floating process, the two roll bodies and the side sealing device are always kept static to the ground, the influence of the roll gap floating process on the side sealing device can be completely eliminated theoretically, and then an infinite process parameter interval is provided theoretically.

Description

Technical Field

[0001] The invention relates to the technical field of double-roller thin strip technology, and in particular to a roller gap floating method for double-roller thin strip. Background Art

[0002] The twin-roll thin strip process was proposed by British metallurgist Sir Bessemer around 1850. Twin-roll thin strip casting machine is also called twin-roll casting machine, twin-roll continuous casting machine, twin-roll casting and rolling machine, twin-roll thin strip machine, twin-roll casting and extrusion machine, etc. The blanks prepared by twin-roll thin strip casting machine are not necessarily thin strips. "Thin strip" is only a habitual name formed for a long time in the technical field involved and belonging to the patent application document of the present invention (hereinafter referred to as "the field"), and "thin strip" includes thin strips, pipes, bars, plates, and other blanks with special cross-sectional shapes.

[0003] In the twin-roll thin strip process, the components constituting the molten pool include two crystallization rollers arranged oppositely and in parallel; the "crystallization roller" is also called a "roller body"; the two crystallization rollers are respectively called a first roller body and a second roller body, and the "first roller body and the second roller body" can be referred to as "two roller bodies" for short; the axis of rotation of the roller body is referred to as a roller shaft for short; by reading the patent application document of the present invention, ordinary technicians in the relevant field can directly and unambiguously know the "roller shaft"; in the patent application document of the present invention, the use of the term "roller shaft" is appropriate, clear and unambiguous; the roller of the first roller body The first roller axis is called the first roller axis, and the roller axis of the second roller body is called the second roller axis. The roller axis is a virtual straight line, and the "first roller axis and the second roller axis" can be referred to as the "two roller axes" for short; the surface of the roller body that directly contacts the material in the molten pool is called the roller body working surface, and the "roller body working surface" is referred to as the "roller surface". Ordinary technicians in the relevant field can directly and unambiguously know the "roller surface"; the surfaces at both ends of the roller body that are perpendicular to the roller axis are called "end surfaces". When a contact side sealing plate is used, part of the "end surface" of the roller body has periodic or non-periodic straight contact with the contact side sealing plate. The minimum distance between the two rolls is called the roll gap; the minimum distance between the two rolls is called the roll gap opening; the roll gap opening can be less than 1 mm; the roll gap opening can also exceed 10 mm; under normal circumstances, for thin steel strips, the roll gap opening is in the range of 0.5 to 3 mm; the midpoint of the roll gap is called the Nip point; in the twin-roll casting process, side sealing devices are often required; contact side sealing devices are a more mature side sealing method; under normal circumstances, contact side sealing devices are generally made of refractory materials and require Under a certain pressure, the rollers are in close contact with the end faces of the rollers. This close contact will cause the side seal device to wear. A cooling water path may be provided inside the rollers. During the preparation process, the two rollers rotate in opposite directions, and materials need to be added to the molten pool. Under the shear driving force provided by the rollers, the materials move out of the molten pool from the roller gap to form a blank with certain specifications. The self-rotation of the crystallization rollers and the viscosity of the cast and rolled materials in the molten pool jointly generate a shear driving force field in the molten pool that promotes the continuous formation of the blank, thus making the twin-roll casting and rolling have the characteristics of "mobile crystallizer technology". The materials entering the molten pool include liquid metal, which can enter the molten pool through a flow distribution device. The materials may include solid substances. For example, when using the twin-roll method to prepare a multi-layer material in a solid-liquid composite manner, solid substances need to be added to the molten pool.

[0004] The molten pool geometry and technical basis of the twin-roll thin strip process are completely different from those of the conventional continuous casting process. In the absence of experimental means, the field believes that the growth law of the solidified shell in the molten pool is as follows: Figure 1 As shown, the thickness of the two solidified shells gradually increases from the meniscus until they are welded together to form a kiss point.

[0005] The inventor disclosed a method for characterizing the transmission behavior in the molten pool during twin-roll casting in Chinese patent document No. 2021101226378; after further experimental research, the inventor improved the tracing method, namely the Kiss angle method, in Chinese patent document No. 2021112909655. The tracing method and the Kiss angle measurement method make it possible to study the actual transmission process in the twin-roll thin strip molten pool.

[0006] The inventors implemented the above-mentioned tracing method and kiss angle measurement method in the laboratory using a twin-roll thin strip caster and found that the actual development process of the "solidified shell" in the molten pool is as follows: Figure 2 shown.

[0007] like Figure 2 The "solidified shell" shown is different from the solidified shell in the traditional sense; Figure 2 The "solidified shell" shown does not have a clear solid phase ratio characteristic as traditionally understood.

[0008] The inventors found that Figure 1 As shown and Figure 2 The difference between the development law of the solidified shell shown in Figure 1 As shown, the two curves converge into a kiss point; Figure 2 As shown in , the two straight lines converge into a kiss point. Figure 2 The experimental results shown show that Figure 1 The understanding shown is essentially wrong. Figure 2 The theoretical schematic diagram of the actual transmission process is shown in Figure 3 shown.

[0009] In the past, the field believed that under ideal conditions, the transmission process in the molten pool of the twin-roll thin strip process is stable; the non-steady-state transmission behavior in the molten pool is caused by external factors, or in other words, the process stability problem and / or the billet quality problem are caused by external factors, including the molten pool depth, the geometry of the flow distribution device, the depth of the flow distribution device immersed in the molten pool, the roller speed, the roller diameter, the roller cooling intensity, the superheat, the roller gap opening and other known process parameters. In summary, the traditional view is that: the instability and / or billet quality problems of the twin-roll thin strip process are caused by external factors; the process instability and / or billet quality problems are due to the lack of appropriate matching of the existing process parameters; the process instability and / or billet quality problems are only due to the difficulty in matching the process parameters, that is, the process instability and / or billet quality problems are only due to the narrow process window of the twin-roll thin strip process.

[0010] For a century and a half, the field has held on to some unproven ideas, including Figure 1The solidification shell development process shown in the figure; in fact, the relevant field does not know that the transmission behavior occurring in the molten pool that they firmly believe in is one-sided; the relevant field firmly believes in such a "basic fact", and this "basic fact" is that the change of the roll gap opening can affect the solidification process in the molten pool; based on this firmly believed "basic fact", some technical personnel in the relevant field have proposed a technical solution for adjusting the development process of the solidification shell by using the roll gap opening.

[0011] The implementation method of the "technical solution of regulating the development process of the solidified shell by using the roller gap opening" is: using a driving device to drive at least one of the two rollers to become a moving roller, so that the two rollers move relative to each other, and the distance between the two rollers changes periodically and / or non-periodically; during the relative movement between the two rollers, the moving roller moves back and forth near the equilibrium position. Figure 4 The zero-angle roll gap floating method shown in the figure is detailed in the Chinese patent document with application number 2017800317704, which discloses a method for operating a twin-roll thin-strip continuous casting machine to reduce vibration; its technical solution is mainly that relative movement occurs between the two roll bodies, so that the opening of the roll gap changes; its technical effect is mainly to reduce the vibration of the casting machine at the expense of the uniformity of the thickness of the billet.

[0012] The casting force is also called the roll clamping force.

[0013] Based on the traditional understanding of "technical solution of adjusting the development process of solidified shell by using roller gap opening", some technicians in the field believe that single-sided roller vibration can refine grains, and single-sided roller vibration will cause relative movement between the two rollers; during the relative movement between the two rollers, the moving roller moves back and forth near the equilibrium position. Figure 5 The single-sided roller shown vibrates in a direction perpendicular to the reference plane. For details, see the Chinese patent document with application number 2007101853779, which discloses a vibrating twin-roller thin strip casting and rolling mill. Its technical solution is mainly that the single-sided roller vibrates, which will cause fluctuations in the roller clamping force and changes in the thickness of the billet. According to public reports, this technology can reduce the probability of scratches on the billet surface. Of course, if the parameters of the roller gap floating (parameters include: frequency; amplitude) are not set properly, scratches will be generated. In fact, in the twin-roller casting process with a single shear force as the driving force, when the shear force is not enough to overcome the resistance encountered during the billet formation process, it will cause the roller surface and the cast metal to slip, thereby generating "scratches". Therefore, the fundamental reason for the scratches is that the driving force cannot overcome the resistance.

[0014] In the patent application document of the present invention, the inventor believes that the relative movement between the two rollers will cause the change of the roller gap. The inventor refers to the change of the roller gap caused by the relative movement between the two rollers as roller gap floating.

[0015] The relative movement between the two rollers causes the Nip point movement. Therefore, in the patent application document of the present invention, roller gap floating can also be referred to as roller gap movement, roller gap movement, Nip point floating, Nip point movement or Nip point movement, etc.

[0016] Due to the existence of side sealing plates and / or considerations of the edge quality of the blank and / or the uniformity of the blank thickness and / or the uniformity of the initial solidification, during the relative movement between the two rollers, the art tries to control the floating speed of the Nip point in the roller axis direction to be as equal to zero or close to zero as possible; that is to say, when it comes to roller gap floating, ordinary technicians in the art can directly and undoubtedly determine that during the relative movement of the two rollers, the roller axes of the two rollers are always parallel or nearly parallel.

[0017] In the traditional technology, there is a method of using the overall movement of a double-roll roller system to generate molten pool oscillation. The Chinese patent document with application number 2022108771736 discloses a molten pool oscillation method for twin-roll casting; "the overall movement of the double-roll roller system" can be referred to as "roll system movement", that is, "roll system movement" refers to the movement of the two rollers as a whole; "roll system movement" does not cause the roller gap to float.

[0018] After the inventors used the tracer method and the kiss angle measurement method to study the transport behavior in the molten pool, the inventors believed that the growth law of the solidified shell in the molten pool is as follows: Figure 2 In the development state shown in FIG. 1 , the inventor proposed in the Chinese patent document with application number 2022101047141 the following Figure 6 The inclined roller gap floating method shown in the Chinese patent document with application number 2022110378783 proposes the following Figure 7 The fixed gap roll floating method shown.

[0019] The inventor disclosed in Chinese patent document No. 2022101047141 a method for yielding motion of a crystallization roll for enhancing the stability of a twin-roll casting process, such as Figure 6 As shown; its technical solution is mainly to control the relative movement between the two rollers so that the roller gap floats. This technical solution will cause fluctuations in the roller clamping force and changes in the thickness of the blank.

[0020] The inventor disclosed a method for moving the crystallization rolls at an angle for twin-roll casting and extrusion in a Chinese patent document with application number 2022110378783, such as Figure 7As shown, the technical solution is mainly that one roller rotates around another roller. This technical solution is to enhance the uniformity of the thickness of the blank. However, this technical solution will still cause fluctuations in the tightening force of the rollers. Moreover, when a contact side sealing device is used, the presence of the side sealing plate will limit the range of process parameters (for example, the size of the relative displacement caused by the relative movement between the roller and the side sealing plate).

[0021] like Figures 4 to 7 The conventional roll gap floating shown is proposed based on the above-mentioned "basic facts" for the purpose of regulating the solidification process.

[0022] In the current industrial practice in the field of nonferrous metals, enterprises are in urgent need of increasing production, optimizing quality, and enriching varieties; among them, higher production is the most urgent and common pursuit; many enterprises use more than a dozen or even dozens of twin-roll casting machines working simultaneously to meet the demand for production. If the output of a single twin-roll casting machine can be increased tenfold, it will mean a dramatic reduction in key costs such as labor and equipment.

[0023] In the current industrial practice in the steel industry, the two-phase zone of a steel grade cannot be too wide or too narrow. In addition, although a few steel grades can be produced commercially, the production process is very sensitive to process parameters and requires extremely high manufacturing precision for core equipment. There are also various process stability issues and / or billet quality issues, resulting in high production costs. Summary of the invention

[0024] The inventors have found through research that, since it is based on the moving crystallizer technology, viscosity (or, stickiness) becomes the basis for the implementation of the twin-roll thin strip process; viscosity is the ability of a substance to resist shear deformation in a moving state; according to "viscosity becomes the basis for the implementation of the twin-roll thin strip process", factors affecting viscosity will affect process stability and\or blank quality; in the past one and a half centuries, the field has carried out long-term, extensive and in-depth research on the solidification process and the control of the solidification process; the solidification process is an important factor affecting viscosity; however, the solidification process is not the only factor affecting viscosity.

[0025] It should be noted that for the twin-roll thin-strip process, due to the special geometric shape of the molten pool, the space for the material to move forward gradually narrows when it moves in the shear force field; therefore, in the molten pool, the resistance experienced by the material along the normal direction (or, reference direction; the explanation of the "reference direction" is detailed below) is not equal to zero; the geometric shape of the molten pool forces the semi-solid metal to undergo shear deformation before moving out of the molten pool; in the process of shear deformation of the semi-solid metal, rheological behavior and / or thixotropic behavior may occur; thixotropic behavior has no significant relationship with the casting speed; and both rheological behavior and thixotropic behavior will lead to macroscopic segregation; therefore, any casting speed may produce segregation caused by shear movement.

[0026] The inventors have found through research that when a semi-solid metal undergoes shear rheological behavior and / or thixotropic behavior, its viscosity will be significantly reduced (by more than two orders of magnitude), which will result in the shear force generated by the rotation of the crystallization roller being unable to be effectively transmitted in the molten pool, or even being interrupted; the double-roll thin strip process is a typical "moving crystallizer technology", and the movement of the cooling substrate (or, the rotation of the crystallization roller) provides a single shear driving force for the formation of the blank; since viscosity is the basis for the transmission of the shear driving force; therefore, when the viscosity suddenly changes and significantly decreases, the shear driving force transmission process becomes unstable, and the "moving crystallizer technology" will in fact not be realized; this (the "moving crystallizer technology" will in fact not be realized) will have an adverse effect on the process stability and / or the quality of the blank.

[0027] It should be noted that, based on the current equipment level, the casting and rolling speed can be precisely controlled; and, when the viscosity is not related to the shear motion, the shear force field can also be accurately predicted and controlled (for example, the preparation of glass sheets and strips using the double-roll method was achieved a hundred years ago); however, when the viscosity is related to the shear motion, the actual motion is quite complex due to the geometry of the molten pool and / or the coupling of multiphase fields, and the changes in viscosity and / or viscosity are difficult to predict and control.

[0028] The inventors have found through research that it is not easy to maintain stable transmission of shear driving force in semi-solid metals due to the shear rheological behavior and / or thixotropic behavior of semi-solid metals. Therefore, it is not easy to maintain stable transmission of shear driving force in semi-solid metals as soon as the two-phase region is wide. For alloy components with narrow two-phase regions, it is difficult for the semi-solid material at the bottom of the molten pool to gather to form a sufficient two-phase region, and the shear force still cannot be effectively transmitted. The static pressure of the molten pool is easily connected (or connected) with the unsolidified core of the billet out of the molten pool, resulting in defects such as ridges, snake eggs, and egg-filled pancakes.

[0029] It can be understood that for semi-solid metals with a wider two-phase zone, the shear driving force provided by the roller rotation is mainly used to promote the movement of the core metal; however, for semi-solid metals with an extremely narrow two-phase zone, the shear driving force provided by the roller rotation is mainly used to hinder the movement of the core metal.

[0030] The inventors have discovered through research that shear motion is another important factor affecting viscosity, and the "moving crystallizer technology" relies on shear motion to achieve continuous formation of the billet; both the solidification process and shear motion will significantly affect the viscosity, and the effect of shear motion on viscosity is unknown in the relevant field; the effect of shear motion on viscosity leads to diverse and common technical problems.

[0031] The inventors have found through research that, as a twin-roll thin strip process based on the "moving crystallizer technology", the effective transmission of driving force is of direct and undoubted importance to both process stability and blank quality; at present, the driving force for blank formation is completely provided by the shear force generated by the rotation of the crystallization roller, which makes the twin-roll thin strip process have difficult-to-overcome defects caused by viscosity mutation in the preparation of metal blanks; to overcome this defect, it is urgent to provide a second driving force; and, under a given phase state, the second driving force should not be affected by viscosity; based on this, pressure (or, to distinguish it from shear force, described as normal force; or, shear-independent driving force) is an ideal second driving force, and the transmission mode of the normal driving force (or, shear-independent driving force) is essentially different from the transmission mode of the shear driving force (or, shear-dependent driving force), and the change in viscosity caused by the form of movement does not affect the transmission of the normal driving force.

[0032] The inventors have found through research that, based on the existing equipment level, the normal driving force capable of driving the formation of the blank can be generated by controlling the relative movement between the two crystallization rollers; and the relative movement between the two crystallization rollers can be quickly and accurately controlled, and the inventors believe that the cost generated is relatively low and should be acceptable to actual production.

[0033] It should be noted that the movement of the cooling matrix provides shear driving force for the continuous formation of the billet; therefore, during the twin-roll casting process, the speed direction of the billet moving out of the molten pool (or, the speed direction of the material at the Nip point) can be at any angle to the gravity direction, which allows the placement of the crystallization rollers to be flexibly set according to actual needs. Although gravity has been proven to have a certain impact on billet quality, gravity cannot be used to modify the shear driving force. Gravity is generally several orders of magnitude smaller than shear force. Gravity is a negligible small force relative to shear force, and the adjustability of gravity is extremely low.

[0034] It should be noted that the normal driving force (or, shear-independent driving force) and the shear driving force (or, shear-dependent driving force) should be of the same order of magnitude.

[0035] It should be noted that for more than a century and a half, the field has not realized the inherent limitations of "mobile mold technology" in preparing metals with strong shear motion on viscosity. The traditional fixed mold technology is driven by the gravity field, and the driving force generated by the gravity field is unrelated to the solidification process and movement; that is, for the traditional fixed mold technology, the driving force provided by the single gravity field is absolutely stable, so the process has achieved widespread success and has a huge social impact; however, as a typical "mobile mold technology", the limitation of the twin-roll thin strip process lies in the transmission process of the single shear driving force generated by the cooling matrix; for the twin-roll thin strip process based on the "mobile mold technology", the transmission process of the shear driving force is affected by viscosity; viscosity is closely related to both the solidification process and movement, and the sub-rapid solidification process of the twin-roll thin strip process is difficult to control, and the special geometry of the twin-roll casting pool makes it inevitable that strong shear motion occurs in the pool.

[0036] The inventors have found through research that when preparing a billet with a wide two-phase region, the viscosity change caused by the shear movement of the semi-solid metal in the molten pool is the key reason why the process is difficult to implement; therefore, for alloy compositions with a wide two-phase region, it is beneficial to apply a normal driving force (or a shear-independent driving force) to the molten pool.

[0037] The inventors have discovered through research that, logically speaking, ordinary technicians in the relevant field can directly and unambiguously understand that lowering the molten pool pressure is beneficial to alloy compositions with narrower two-phase regions; lowering the molten pool pressure can promote the aggregation of semi-solid materials at the bottom of the molten pool by suppressing the rapid flow of the core melt, thereby achieving the effect of preventing the static pressure in the molten pool from being connected to the unsolidified core of the billet leaving the molten pool, thereby avoiding defects such as ridges, snake eggs, and egg-filled pancakes.

[0038] It should be noted that when using the twin-roll casting process to prepare steel thin strips, the thickness of the side sealing plate is generally around 40mm; it must be ensured to be above 6mm during the production process, otherwise it may break; 8mm is generally used in actual production on site to avoid accidents caused by accidental breakage of the side sealing plate as much as possible.

[0039] The inventors have found through research that keeping the roller body and the side sealing plate relatively still during the roller gap floating process is of great significance for enhancing the service life of the side sealing plate and / or process stability and / or blank quality. Figure 8 The side cover is shown before use; Fig. 9 The side sealing plate after use is shown in the figure. Due to the wear of the side sealing plate and the end surface of the roller during contact, the following Fig. 9 The slope shown in the figure can contact the working surface of the roller body, and a gap can be formed between the slope and the working surface of the roller body. Figure 8Side sealing plate shown; then, the relative movement displacement of the roller and the side sealing device needs to be limited within a certain range to prevent the melt from entering the gap between the slope surface and the working surface of the roller, causing process instability or process interruption or quality problems on the edge of the blank.

[0040] It can be understood that “keeping the roller body and the side sealing plate relatively still” can also be expressed as: keeping the positions of the roller body and the side sealing plate relative to the ground unchanged.

[0041] It is understandable that a person skilled in the art can directly and without doubt know that “keeping the position of the roller body relative to the ground unchanged” does not take into account the self-rotation of the roller body.

[0042] The inventors have found through research that the control of the float of the roll gap and the movement of the roll system occur simultaneously and synchronously, and the changes in the placement plane caused by the process of controlling the float of the roll gap and the changes in the placement plane caused by the movement of the roll system are offset in real time and completely, so that the two rolls always remain stationary relative to the ground; in this way, the parameter setting of the float of the roll gap is only limited by the equipment, and the theoretically optimal process stability and / or the optimal blank quality can be obtained.

[0043] The inventors have found that the floating of the roller gap and the movement of the roller system are controlled to occur simultaneously and synchronously, and the changes in the placement plane caused by the floating process of the roller gap and the changes in the placement plane caused by the movement process of the roller system are offset in real time and completely, so that the two rollers always remain stationary relative to the ground; in this way, the working surface of the roller body and the Fig. 9 There will be no gaps between the slope surfaces shown or the gaps will only be caused by errors, which can avoid process instability or process interruption or quality problems of the edges of the blank.

[0044] The inventors have discovered through research that the roller gap floating is caused by the alternating movement of the two rollers, which is of great significance to the uniformity of the blank's structure. This significance is mainly reflected in two aspects: one is the uniformity of the blank's macro and micro structures; the other is the stability of the blank's morphology. If during the preparation process, only one roller moves relative to the ground, while the other roller remains stationary relative to the ground, then when the roller gap floating causes a change in the placement plane, this roller gap floating will usually lead to stability problems in the blank's morphology, for example, bending of the blank.

[0045] It can be understood that "roller gap floating is caused by the alternating movement of the two rollers", wherein "alternating movement of the two rollers" can also be expressed as: "without considering the influence of the roller system movement, the two rollers move alternately relative to the ground"; or, "without considering the influence of the roller system movement: the first roller is stationary relative to the ground, and the second roller moves relative to the ground; then, the first roller moves relative to the ground, and the second roller is stationary relative to the ground"; or, "without considering the influence of the roller system movement: the first roller moves relative to the ground, and the second roller is stationary relative to the ground; then, the first roller is stationary relative to the ground, and the second roller moves relative to the ground".

[0046] It should be noted that even if “the roller gap floating is generated by the alternating motion of the two roller bodies” is not explained, ordinary technicians in the relevant field can directly and unambiguously understand the specific method of “the alternating motion of the two roller bodies”.

[0047] In order to solve the current technical problems and further improve the process stability and / or the quality control level of the blank, the patent application document of the present invention provides a roll gap floating method for a double-roll thin strip, wherein the roll system is movably arranged on a double-roll thin strip casting machine as a whole, and the roll system includes a first roll body and a second roll body which are arranged oppositely for preparing the blank; the roll axis of the first roll body is called the first roll axis, and the roll axis of the second roll body is called the second roll axis; the plane where the first roll axis and the second roll axis are located is called the placement plane of the roll system; The method comprises the steps of: First floating: the second roller body is stationary relative to the ground, and the first roller body is controlled to rotate around the second roller axis without stopping. At the same time, the roller system is controlled to rotate around the second roller axis, and the placement plane is always stationary relative to the ground; Second floating: the first roller body is stationary relative to the ground, and the second roller body is controlled to rotate around the first roller axis without stopping. At the same time, the roller system is controlled to rotate around the first roller axis, and the placement plane is always stationary relative to the ground; In one preparation process, the first floating occurs at least once, and the second floating occurs at least once.

[0048] It is understandable that in the actual process, due to the "load generated during the preparation process" and / or "deliberately designed roller shape", the roller axes of the two rollers are approximately straight lines; in fact, in the field of the same field, when studying the molten pool transfer behavior and / or roller gap floating, under normal circumstances, the roller axes are generally considered to be absolutely straight lines, that is, the two rollers are considered to be ideal rigid rotating bodies. For example: for an equal-diameter twin-roller thin strip caster, the roller body is a cylinder; a cylinder consists of two bottom surfaces and a side surface; the two bottom surfaces of the cylinder are two completely identical circular surfaces; the side surface of the cylinder is a curved surface; the two end surfaces of the roller body are the two bottom surfaces of the cylinder, and the roller surface of the roller body is the side surface of the cylinder.

[0049] It should be noted that a person skilled in the art can directly and without doubt determine that during the relative movement between the two rollers to cause the roller gap to float, the axes of the two rollers are always parallel.

[0050] It should be noted that ordinary technicians in the relevant field can directly and unambiguously understand the “first roller”, “second roller”, and “two rollers”.

[0051] It should be noted that ordinary technicians in the relevant field can directly and unambiguously determine that "the two rollers are always parallel" includes "the two rollers are always nearly parallel"; among them, "the two rollers are always nearly parallel" means that there may be a definite but unavoidable deviation between the "parallel" that can be achieved under the current technical conditions and the "absolute, idealized parallel".

[0052] It can be understood that, in the patent application documents of the present invention, "parallel" includes "nearly parallel"; that is, "parallel" should be understood as "parallel or nearly parallel", or "substantially parallel", or "approximately parallel".

[0053] It is understandable that, since the two rollers are parallel, the placement plane can be determined by the plane where the two rollers are located; since it is impossible to achieve "absolute parallelism", in the actual preparation process, the placement plane can also be determined by points on the two rollers that are less affected by changes in the preparation process. For example, the placement plane is determined by using the four intersection points or any three intersection points of the two rollers and the end faces of the two roller bodies. Another example: take two points on the first roller where the roller axis intersects with the end faces of the roller body, and take a point on the second roller that is closest to the center of gravity of the second roller body to determine the placement plane. Another example: take any two points on the first roller and any one point on the second roller to determine the placement plane.

[0054] It is understandable that a plane perpendicular to one roller axis can be selected; then, the line connecting the intersection of this plane and the two roller axes is used to represent the placement plane.

[0055] It should be noted that a person skilled in the art can directly and unambiguously know the “first float” and the “second float”: wherein, “first” and “second” are not used to limit the order of generation.

[0056] It should be noted that a person skilled in the art can directly and without doubt know that for “first floating: the second roller body is stationary with respect to the ground, the first roller body is controlled to make a non-stop rotation around the second roller axis, and at the same time, the roller system is controlled to rotate around the second roller axis, and the placement plane is always stationary with respect to the ground”, according to “the first roller body is controlled to make a non-stop rotation around the second roller axis, and at the same time, the roller system is controlled to rotate around the second roller axis, and the placement plane is always stationary with respect to the ground”, if the reference system does not change, then: if the first roller body rotates clockwise around the second roller axis, the roller system rotates counterclockwise around the second roller axis; if the first roller body rotates counterclockwise around the second roller axis, the roller system rotates clockwise around the second roller axis.

[0057] It should be noted that a person skilled in the art can directly and without doubt know that for "first floating: the second roller body is stationary with respect to the ground, the first roller body is controlled to rotate around the second roller axis without stopping, and at the same time, the roller system is controlled to rotate around the second roller axis, and the placement plane is always stationary with respect to the ground", wherein, "the angular velocity of the first roller body rotating around the second roller axis" and "the angular velocity of the roller system rotating around the second roller axis" are the same in magnitude, but in opposite directions.

[0058] It should be noted that a person skilled in the art can directly and without doubt know that for “second floating: the first roller body is stationary with respect to the ground, the second roller body is controlled to make a non-stop rotation around the first roller axis, and at the same time, the roller system is controlled to rotate around the first roller axis, and the placement plane is always stationary with respect to the ground”, wherein, according to “the second roller body is controlled to make a non-stop rotation around the first roller axis, and at the same time, the roller system is controlled to rotate around the first roller axis, and the placement plane is always stationary with respect to the ground”, it can be known that if the reference system does not change, then: if the second roller body rotates clockwise around the first roller axis, the roller system rotates counterclockwise around the first roller axis; if the second roller body rotates counterclockwise around the first roller axis, the roller system rotates clockwise around the first roller axis.

[0059] It should be noted that a person skilled in the art can directly and without doubt know that for “second floating: the first roller body is stationary with respect to the ground, the second roller body is controlled to make one non-stop rotation around the first roller axis, and at the same time, the roller system is controlled to rotate around the first roller axis, and the placement plane is always stationary with respect to the ground”, wherein “the angular velocity of the second roller body rotating around the first roller axis” and “the angular velocity of the roller system rotating around the first roller axis” are the same in magnitude but in opposite directions.

[0060] It should be noted that ordinary technicians in the relevant field can directly and unambiguously know that "the first roller is stationary relative to the ground" does not include the rotation of the first roller itself; similarly, "the second roller is stationary relative to the ground" does not include the rotation of the second roller itself.

[0061] It can be understood that since "the second roller body is stationary with respect to the ground, the first roller body is controlled to make a non-stop rotation around the second roller axis, and at the same time, the roller system is controlled to rotate around the second roller axis", the opening of the roller gap does not change during the "first floating" process.

[0062] It can be understood that since "the first roller body is stationary with respect to the ground, the second roller body is controlled to make a non-stop rotation around the first roller axis, and at the same time, the roller system is controlled to rotate around the first roller axis", the opening of the roller gap does not change during the "second floating" process.

[0063] It can be understood that "the second roller body is stationary relative to the ground, the first roller body is controlled to rotate once around the second roller axis without stopping, and at the same time, the roller system is controlled to rotate around the second roller axis", where "rotation" means: during the relative movement between the two roller bodies, the first roller body performs a circular motion around the second roller axis (or the second roller body), and the roller gap opening is constant. Similarly, it also applies to "the first roller body is stationary relative to the ground, the second roller body is controlled to rotate once around the first roller axis without stopping, and at the same time, the roller system is controlled to rotate around the first roller axis".

[0064] It can be understood that "controlling the first roller to rotate once without stopping around the second roller axis", wherein "the first roller to rotate once without stopping around the second roller axis" is achieved by "a non-stop relative motion between the first roller and the second roller"; the same applies to "controlling the second roller to rotate once without stopping around the first roller axis".

[0065] It should be noted that "a non-stop relative motion between the first roller and the second roller is completed", wherein "a non-stop relative motion" means: from the moment when the relative motion between the two rollers occurs until the end of this relative motion; and at the starting moment and the ending moment of this relative motion, the speed of one of the two rollers relative to the other roller is equal to zero.

[0066] It can be understood that once a relative motion between the two rollers begins, as long as the relative speed between the two rollers is equal to zero, the relative motion is declared to be over.

[0067] It can be understood that in the patent application document of the present invention, during the relative movement between the two rollers, the first roller rotates around the second roller axis (or the second roller rotates around the first roller axis; or the first roller rotates around the second roller; or the second roller rotates around the first roller), wherein "rotation" refers to circular motion.

[0068] It should be noted that ordinary technicians in the relevant field can directly and unambiguously determine that "the placement plane is always stationary with respect to the ground" includes "the placement plane is always nearly stationary with respect to the ground"; wherein, "the placement plane is always nearly stationary with respect to the ground" means: there may be a definite but unavoidable deviation between the "stationary" that can be achieved under the current technical conditions and the "absolute, idealized stationary".

[0069] It is understandable that, in the patent application document of the present invention, "the placement plane is always stationary relative to the earth", wherein "stationary" includes "almost stationary"; that is, "stationary" should be understood as "stationary or nearly stationary", or "basically stationary", or "approximately stationary".

[0070] Furthermore, a roll gap floating method for a double-roll thin strip, wherein the minimum distance between the first roller body and the second roller body is called the roll gap; the midpoint of the roll gap is called the Nip point; the moving speed of the blank at the Nip point is called the preparation speed; the moving speed of the Nip point caused by the relative movement between the first roller body and the second roller body is called the floating speed of the Nip point; during each occurrence of the first floating, the inner product of the floating speed and the preparation speed is called the first inner product; during each occurrence of the second floating, the inner product of the floating speed and the preparation speed is called the second inner product; during each occurrence of the first floating, the first inner product is always less than zero; and during each occurrence of the second floating, the second inner product is always less than zero.

[0071] It should be noted that the moving speed of the billet (or thin strip; or material; or cast-rolled material) at the Nip point is called the preparation speed; the preparation speed is used to measure the speed of the billet preparation process; the direction of the preparation speed is called the preparation direction; the preparation direction is always perpendicular to the placement plane.

[0072] It should be noted that the normal of the placement plane is called the placement normal; there are countless placement normals.

[0073] It can be understood that the preparation speed reflects the speed of the blank preparation process; the size of the preparation speed is only related to the opposite rotation of the two rollers, and has nothing to do with the movement of the roller system and the relative movement between the two rollers; the preparation direction is always along the placement normal and points to the direction of the blank moving out of the molten pool.

[0074] It should be noted that the component speed of "floating speed" in the preparation direction is also called "effective speed".

[0075] It can be understood that the "floating speed" can be decomposed into "the component speed in the preparation direction" and "the component speed on the placement plane".

[0076] It is to be understood that both the "floating speed" and the "preparation speed" are vectors (or, vectors).

[0077] It should be noted that, in the natural state: the placement plane where the first roller and the second roller are located is also called the reference plane; the preparation speed is also called the reference speed; and the preparation direction is also called the reference direction.

[0078] It can be understood that the "natural state" refers to a state in which the positions of the two rollers relative to the ground do not change from beginning to end during the preparation process; that is, during the preparation process, the "roller gap floating process" mentioned in the patent application document of the present invention has never occurred, and the "roller system movement process" mentioned in the patent application document of the present invention has never occurred; in fact, it is precisely because the preparation process under the natural state has various process stability problems and / or blank quality problems that the relevant field has proposed the following. Figures 4 to 7 The conventional roll gap floating method is shown.

[0079] It should be noted that, in a natural state, the normal line of the reference plane passing through the Nip point is called a reference line.

[0080] It is understandable that, during the preparation process in a natural state, there is no relative movement between the two rollers, and there is no roller system movement; therefore, the floating speed is equal to zero, and the placement plane does not change.

[0081] It can be understood that the reference plane is a unique plane determined by the form of the twin-roll casting machine; for a horizontal equal-diameter twin-roll casting machine, the reference plane is parallel to or coincides with the horizontal plane; for an inclined twin-roll casting machine, the reference plane is a plane that forms a fixed angle with the horizontal plane.

[0082] It can be understood that, for the horizontal equal-diameter twin-roll casting machine, during the preparation process, no matter how complicated the roll gap floating process and / or the roll system movement process occurs, the position of the reference plane and the reference line relative to the ground remains unchanged; the same applies to other forms of twin-roll casting machines.

[0083] It can be understood that, unlike the placement plane, the reference plane is a fixed plane, that is, the float of the roll gap or the movement of the roll system will not affect the position of the reference plane, because: the range of the float of the roll gap or the movement of the roll system is constrained by the form of the twin-roll thin strip casting machine.

[0084] It is understandable that in three-dimensional space, the roll gap is actually a surface, countless Nip points form a Nip line, and countless Kiss points form a Kiss line; however, in fact, "Nip line" and "Kiss line" are rarely mentioned in the relevant field; for many years, "Nip point" and "Kiss point" have been widely used in the relevant field; and, when "Nip point" and "Kiss point" are used to describe the molten pool transfer behavior and / or roll gap floating involved in the patent application document of the present invention, it is not necessary to specifically state that it is on a plane perpendicular to the roller axis, that is, using "Nip point" and "Kiss point" to describe is actually a common practice in the relevant field; in the patent application document of the present invention, in order to describe the proposed technical solution, according to the common practice in the relevant field, a plane perpendicular to the roller axis is selected, and then the technical features of the proposed technical solution are expressed on this plane. This is the clearest way and it is also the way that ordinary technicians in the relevant field can understand directly and without doubt.

[0085] It should be noted that ordinary technicians in the relevant field can directly and unambiguously understand that "the midpoint of the roll gap is called the Nip point".

[0086] It is understandable that when studying the floating process of the roll gap, the two roll bodies are regarded as ideal rigid rotating bodies with two roll axes arranged in parallel, and the floating speed law of the Nip point on any plane perpendicular to the roll axes is the same. Therefore, in order to study the floating process of the roll gap, the method that ordinary technicians in the relevant field can directly and unambiguously understand is: Take any plane Ω perpendicular to the roller axis i ; Nip Line and Planar Ω i The intersection point is called Nip point N i ; Research Nip Point N i laws of movement.

[0087] It can be understood that, from the normal plane of the reference plane, the normal plane passing through the Nip line in the natural state is selected as the reference plane Π i ; Reference plane Π i With plane Ω i The intersection line is called the reference line π i .

[0088] It can be understood that, without considering the influence of the roller system movement, during the relative movement between the two rollers, the Nip line and Nip point N i And the placement plane can move relative to the ground.

[0089] It can be understood that “the influence of roller system motion is not considered” can also be expressed as: “no roller system motion occurs, or the influence of roller system motion is eliminated”.

[0090] It can be understood that “eliminating the influence caused by the movement of the roller system”, wherein “eliminating” can also be expressed as: removing; or, removing; or, excluding.

[0091] It can be understood that during the relative motion between the two rollers, the reference plane and the plane Ω i , reference plane Π i , reference line π i Its position relative to the ground is fixed.

[0092] It is understandable that there are countless normals to the reference plane; however, in the patent application document of the present invention, the normal of the reference plane passing through the Nip point in the natural state is selected as the reference line; that is, the reference line has two characteristics, the reference line is the normal of the reference plane, and the reference line passes through the Nip point in the natural state.

[0093] It can be understood that the reference line is the normal line of the reference plane passing through the Nip point in the natural state.

[0094] It is understandable that in three-dimensional space, there are countless "Nip points"; there are also countless reference lines, and countless reference lines form a "reference plane".

[0095] It is understandable that whether the reference line passes through the Nip point in the natural state does not affect the description of the protection scope in the patent application document of the present invention.

[0096] It should be noted that if Fig.10 As shown, a horizontal equal-diameter twin-roll casting machine is used for explanation. A plane perpendicular to the roller axis is randomly selected, and then a schematic diagram of the relationship between the two roller bodies, the two roller axes, the placement plane, the reference plane, the roller gap, the Nip point, the reference line, the speed at which the roller surface passes through the roller gap, the preparation speed, the preparation direction and the reference direction under different conditions is displayed on this plane.

[0097] It is understandable that "under different conditions" can also be expressed as: "under natural conditions, or, under unnatural conditions".

[0098] It should be noted that if Fig.10 As shown, "perpendicular foot" is a symbol used to indicate a perpendicular relationship; "perpendicular foot" is also called "perpendicular sign" or "perpendicular foot sign".

[0099] It should be noted that if Fig.10 As shown in the “speed of the roller surface passing through the roller gap”, since the roller body is regarded as an ideal rigid rotating body, the “direction of the speed of the roller surface passing through the roller gap” and the “direction of the preparation speed” are always the same; that is, the “direction of the speed of the roller surface passing through the roller gap” and the “preparation direction” are always the same.

[0100] It should be noted that if Fig.10 As shown, in the natural state, the plane where the two rollers are located is called the reference plane, and the direction of the moving speed of the blank at the Nip point is called the "reference direction"; the "reference direction" is always perpendicular to the reference plane; in the natural state, the placement plane coincides with the reference plane, and the preparation direction is the same as the reference direction; that is to say, the reference plane is a special case of the placement plane, the reference direction is a special case of the preparation direction, and the reference line is a special case of the placement normal.

[0101] It should be noted that "during the process of the first floating, the inner product of the floating speed and the preparation speed is called the first inner product; during the process of the second floating, the inner product of the floating speed and the preparation speed is called the second inner product; the first inner product and / or the second inner product is always greater than zero", among which, ordinary technicians in the relevant field can directly and unambiguously know the "inner product".

[0102] It should be noted that in the three-dimensional rectangular coordinate system (X, Y, Z), let vector U = [x1, y1, z1], let vector V = [x2, y2, z2], then the inner product of vector U and vector V is: U·V=x1x2+y1y2+z1z2.

[0103] It should be noted that the "inner product" is also called the "scalar product"; or the "dot product".

[0104] It should be noted that the "roller system" is also called a "double-roller roll system"; the relative movement between the two rolls belongs to the internal movement of the roll system, and the internal movement of the roll system will cause the roll gap to float.

[0105] It should be noted that the rolls on the twin-roll thin strip caster can move as a whole.

[0106] It should be noted that the movement of the roller system will not cause a change in the relative position between the two roller bodies; that is, the movement of the roller system will neither cause the roller gap to float nor affect the roller gap to float.

[0107] It can be understood that during the first floating process, the changes in the placement plane caused by "controlling the first roller to rotate once without stopping around the second roller axis" and the changes in the placement plane caused by "controlling the roller system to rotate around the second roller axis" are offset in real time; therefore, the position of the placement plane relative to the ground does not change in appearance. The same is true for the second floating.

[0108] It is understandable that "apparently, the position of the placement plane relative to the ground does not change" can also be expressed as: "Ignoring the rotation of the rollers, apparently, the positions of the first roller and the second roller relative to the ground do not change."

[0109] It should be noted that, although "apparently, the positions of the first roller and the second roller relative to the ground do not change", when "the inner product of the floating speed and the preparation speed" is less than zero, a driving force that is independent of viscosity (or shear independent) can still be applied to the semi-solid material in the molten pool; ordinary technicians in the relevant field can directly and unambiguously understand that 'apparently, the positions of the first roller and the second roller relative to the ground do not change, but when "the inner product of the floating speed and the preparation speed" is less than zero, a driving force that is independent of viscosity can still be applied to the semi-solid material in the molten pool' is not metaphysics.

[0110] It should be noted that it is indeed difficult for a very few technical personnel to understand that "apparently, the positions of the first roller and the second roller relative to the ground do not change, but when 'the inner product of the floating speed and the preparation speed' is less than zero, a driving force unrelated to viscosity can still be applied to the semi-solid material in the molten pool." Ordinary technical personnel can understand that the reason why "a very few technical personnel" find it difficult to understand is that there is indeed a problem with the IQ of "a very few technical personnel", not that there is a problem with the description of the technical solution of this patent; "ordinary technical personnel" and "a very few technical personnel" are different.

[0111] It should be noted that although "apparently, the positions of the first roller and the second roller relative to the ground do not change", the pressure in the molten pool can still be reduced when "the inner product of the floating speed and the preparation speed" is greater than zero.

[0112] It can be understood that "the placement plane changes" means: when there is no roller system movement (or the influence of the roller system movement is eliminated), there is no relative movement between the two roller bodies (or in a natural state), assuming that the two roller axes are located in the placement plane θ 1s ; After the relative movement between the two roller bodies occurs, the two roller axes are located on the placement plane Θ 2s ; Plane Θ 1s and plane Θ 2s Non-coincidence, plane Θ 1s and plane Θ 2s Intersecting or parallel.

[0113] It can be understood that at the starting moment of the first float (or, the second float), the effective speed is equal to zero; at the ending moment of the first float (or, the second float), the effective speed is equal to zero; between the starting moment and the ending moment of a first float (or, the second float), there is no moment when the effective speed is equal to zero; that is to say, during the process of a first float (or, the second float), the effective speed is never equal to zero.

[0114] It can be understood that the rolls move on the twin roll casting machine; however, if there is no relative movement between the two roll bodies; then, the floating speed is equal to zero and the effective speed is equal to zero.

[0115] It can be understood that, as mentioned above, "effective speed" is the component speed of "floating speed" in the preparation direction; "effective speed" and / or "change in effective speed" can be used to measure the extent of the effect of the roll gap floating process on the molten pool transfer behavior.

[0116] It can be understood that at a certain moment during the first float (or the second float), the ground velocity of the Nip point (expressed by vector V T The velocity of the Nip point relative to the ground caused by the roller system motion is represented by the vector V W On the other hand, due to the relative motion between the two rollers, the ground velocity of the Nip point is represented by the vector V F Then, floating speed = V F =V T -V W ; Due to V T =0; therefore, V F =-V W .

[0117] It is understood that in the present patent application document, the "floating speed" (or, vector V F ) is completely unrelated to the roller system movement. This is because: the simple roller system movement will cause the Nip point to change its position relative to the ground, and the simple roller gap floating process will also cause the Nip point to change its position relative to the ground; however, the simple roller system movement and the simple roller gap floating process have completely different effects on the molten pool transmission behavior; if only the roller system movement occurs, and the roller gap floating does not occur; then, there is no need to talk about the change process of the Nip point state; because, talking about the change process of the Nip point state without the roller gap floating is meaningless for the patent application document of this invention.

[0118] It can be understood that, according to the above explanation of "floating speed", it can be clarified that: "floating speed" must be generated only by the relative movement between the two rollers.

[0119] It should be noted that even without giving the above detailed explanation of the “floating speed”, a person skilled in the art can directly and without doubt know that the “floating speed” must be generated only by the relative motion between the two rollers.

[0120] It should be noted that ordinary technicians in the relevant field can directly and unambiguously determine that "the floating speed is equal to zero" and "the effective speed is equal to zero", where "equal to zero" includes "approaching to zero"; "approaching to zero" means that under the current technical conditions, there may be a definite but unavoidable deviation between "speed" and "zero". For example, during the preparation process, the two rollers are deformed and vibrated under load, which cannot be absolutely eliminated; or during the movement of the rollers, since the transmission behavior in the molten pool is not carried out under ideal conditions, this will also lead to an unavoidable deviation between the actual movement of the rollers and the set movement.

[0121] It is understood that, in the patent application document of the present invention, if there is no special explanation, "equal to zero" includes "approaching to zero"; that is, "equal to zero" should be understood as "equal to zero or approaching to zero", or "substantially equal to zero", or "approximately equal to zero". For example, "angular velocity equal to zero" should be understood as: "angular velocity equal to zero or approaching to zero"; or, "angular velocity substantially equal to zero"; or, "angular velocity approximately equal to zero".

[0122] It should be noted that what ordinary technicians in the relevant field can directly and undoubtedly determine is that during the movement of the roller system, the two roller bodies move as a "whole" on the twin-roll thin strip casting machine, and the components on the twin-roll thin strip casting machine that are directly and / or indirectly connected to the first roller body and / or the second roller body, such as side sealing devices, flow distribution devices, driving mechanisms, etc., can be set to follow the movement of the roller system or not as needed; it is only necessary to ensure that the relative movement between the two roller bodies and the movement of the roller system can operate without interfering with each other; that is, it is only necessary to ensure that the movement of the roller system and the movement inside the roller system can operate without interfering with each other.

[0123] It can be understood that, at the start and end of the first floating: the effective speed is equal to zero; the floating speed is equal to zero.

[0124] It can be understood that "the floating speed is equal to zero" means "no relative movement occurs between the two rollers".

[0125] It can be understood that, similar to the "first float", at the start and end of the second float: the effective speed is equal to zero; the floating speed is equal to zero.

[0126] It can be understood that "the first inner product is less than zero" means that: during the first floating process, the inner product of the floating speed and the preparation speed is less than zero, so as to allow the molten pool pressure to be actively increased and a normal driving force independent of viscosity to be applied to the semi-solid material in the molten pool, so as to maintain the stability of the total driving force and promote the updating of the Kiss angle.

[0127] It should be noted that in the process of preparing the billet using the twin-roll method, especially in the process of preparing aluminum and its alloys, and magnesium alloys, the precipitation of hydrogen will cause micron-sized shrinkage holes to appear in the final product; the inventors have found through research that "the inner product of the floating speed and the preparation speed is less than zero" can apply pressure to the molten pool, and this pressure will reduce the probability of shrinkage holes appearing, thereby improving the quality of the billet.

[0128] Furthermore, in a roll gap floating method for a double-roll thin strip, during each occurrence of the first floating, the first inner product is always greater than zero.

[0129] It can be understood that “the first inner product is greater than zero” means that during the first floating process, the inner product of the floating speed and the preparation speed is greater than zero, so as to allow the molten pool pressure to be actively reduced and the kiss angle update to be suppressed.

[0130] It can be understood that "the first inner product is greater than zero", then, during each first floating process (or, between the start and end times of each first floating process), the inner product of the floating speed and the preparation speed is greater than zero; "during each first floating process, the inner product of the floating speed and the preparation speed is greater than zero" means, during each first floating process, let the preparation speed be vector U, let the floating speed be vector V, then the inner product of vector U and vector V is always greater than zero.

[0131] It is understandable that “always greater than zero” can also be expressed as “always a positive value”.

[0132] It can be understood that “the first inner product is greater than zero” means: in each process of the first floating, let the preparation speed be vector U, and let the floating speed be vector V; then, the inner product of vector U and vector V is always greater than zero.

[0133] It is understandable that “between the starting time and the ending time” does not include the “starting time” or the “ending time”; that is, “between the starting time and the ending time” does not include the end value.

[0134] It should be noted that "actively increasing the molten pool pressure" can improve the heat transfer performance of the roller, which is beneficial to increasing production and improving the green body structure.

[0135] Furthermore, in a roll gap floating method for a double-roll thin strip, during each occurrence of the first floating, the first inner product is always less than zero.

[0136] It can be understood that "the first inner product is always less than zero", so during each first float (or between the start and end times of each first float), the inner product of the floating speed and the preparation speed is less than zero.

[0137] It can be understood that "in each process of the first floating, the first inner product is always less than zero" means: in each process of the first floating, let the preparation speed be vector U, and let the floating speed be vector V; then, the inner product of vector U and vector V is always less than zero.

[0138] It is understandable that “always less than zero” can also be expressed as “always a negative value”.

[0139] It should be noted that, before the present inventors, due to the lack of methods to study actual transmission behavior, during the process of blank formation, the transmission behavior of high-temperature materials in the molten pool under the action of a single shear driving force provided by the cooling matrix has not been studied experimentally. It should be acknowledged that while the self-rotation of the crystallization roller provides a shear driving force for the continuous formation of the blank, it also brings difficulties to the real-time monitoring of the transmission behavior in the molten pool. For the double-roller thin strip process, it is impossible to monitor the actual transmission process of the molten pool in real time by "setting a thermocouple in the crystallization roller". The consensus in the field is that finding a method to study the actual transmission behavior is crucial to understanding the root causes of process stability problems and blank quality problems, which is also an important driving force for the continuous complexity of mathematical models. In the early research process, the present inventors proposed a method to study the actual transmission behavior in the molten pool. By implementing the method of studying the actual transmission behavior, the present inventors discovered the shear rheological behavior of semi-solid materials in the molten pool that is unknown in the field, and the shear rheological behavior leads to macroscopic segregation. By analyzing the discovered "shear rheological behavior of semi-solid materials", the inventors realized that both the solidification process and shear motion (shear motion will cause shear rheology or thixotropic behavior) will change the viscosity, thereby affecting the transmission process of the shear driving force. The influence of "shear motion causing viscosity changes" on the transmission process of the shear driving force is the root cause of many technical difficulties that have not been noticed in the relevant field. Based on the detailed study of "the influence of shear motion on viscosity", the inventors proposed to use the relative motion between the two crystallization rollers to make "the inner product of the floating speed and the preparation speed" less than zero to achieve the application of the second normal driving force, with the purpose of reducing or eliminating the influence of shear motion on viscosity, so that the total driving force can be kept stable, thereby enhancing the process stability and\or improving the quality of the blank.

[0140] It should be noted that according to the inventor's previous research in "Numerical Simulation of the Fluid Flow, Heat Transfer, and Solidification during the Twin-Roll Continuous Casting of Steel and Aluminum" (Metallurgical and Materials Transactions B, 2016, P740-748), using a 400 mm diameter crystallization roll, the momentum transfer and heat transfer process in the molten pool can support a casting speed of 30 m / min; of course, this does not take into account the interaction between shear motion and viscosity; that is, if the effect of shear motion on viscosity can be avoided by applying a normal driving force ("the inner product of the floating speed and the preparation speed is less than zero"), from the perspective of momentum transfer and heat transfer, it is feasible to increase the casting speed to 30 m / min.

[0141] Furthermore, in a roll gap floating method for a double-roll thin strip, during each occurrence of the first floating, the first inner product is always greater than zero; and during each occurrence of the second floating, the second inner product is always greater than zero.

[0142] It should be noted that the inventors have discovered through research that for some alloy components, the two-phase region materials at the bottom of the molten pool are difficult to gather. Therefore, under the action of the "molten pool pressure", the "material in the molten pool" is transferred to the "unsolidified area of ​​the core of the billet out of the molten pool", resulting in problems such as egg-filled pancakes, snake eggs, ridges, etc.; by reducing the molten pool pressure, this inappropriate material transfer phenomenon can be effectively avoided, thereby avoiding problems such as egg-filled pancakes, snake eggs, ridges, etc.

[0143] Furthermore, a roll gap floating method for a double-roll thin strip is provided, wherein the occurrence frequency of the first floating and / or the second floating is in the range of 0.1 to 5 Hz.

[0144] Furthermore, a roll gap floating method for a double-roll thin strip is provided, wherein the occurrence frequency of the first floating and / or the second floating is in the range of 0.01 to 10 Hz.

[0145] Further, a roll gap floating method for a double-roll thin strip, in a single preparation process, occurs in any of the following ways: The first floating occurs once and the second floating occurs once, wherein the first floating occurs once and the second floating occurs once in any combination; The first floating occurs once and the second floating occurs multiple times, wherein the first floating occurs once and the second floating occurs multiple times in any combination; A plurality of the first floating and a plurality of the second floating occur, wherein the plurality of the first floating and the plurality of the second floating are any combination.

[0146] It can be understood that "the first floating occurs once and the second floating occurs once, wherein the first floating occurs once and the second floating occurs once in any combination", wherein, since "the first floating occurs once and the second floating occurs once", therefore, "the first floating occurs once and the second floating occurs once in any combination" actually has two options: the first floating occurs first and then the second floating occurs; the second floating occurs first and then the first floating occurs.

[0147] Further, a roll gap floating method for a double-roll thin strip, in a single preparation process, occurs in any of the following ways: The number of occurrences of the first floating is equal to the number of occurrences of the second floating; The number of occurrences of the first floating is greater than the number of occurrences of the second floating; The number of times the first floating occurs is less than the number of times the second floating occurs.

[0148] Furthermore, a roller gap floating method for a double-roll thin strip is provided, in which the first floating occurs once or multiple times and then the second floating occurs once or multiple times during the entire or partial time of the preparation process; or, in which the second floating occurs once or multiple times and then the first floating occurs once or multiple times during the entire or partial time of the preparation process.

[0149] Furthermore, a roller gap floating method for a double-roll thin strip is provided, wherein the first floating and the second floating occur sequentially and repeatedly during part or all of the time in a preparation process; or, the second floating and the first floating occur sequentially and repeatedly during part or all of the time in a preparation process.

[0150] It can be understood that "the first floating and the second floating occur sequentially and repeatedly" and "the second floating and the first floating occur sequentially and repeatedly" are two equivalent description methods; because "first" and "second" are not used to indicate order; in the patent application document of the present invention, "the first floating and the second floating occur sequentially and repeatedly" and "the second floating and the first floating occur sequentially and repeatedly" are used at the same time to emphasize that "'first' and 'second' are not used to indicate order".

[0151] Furthermore, a roller gap floating method for a double-roll thin strip, during each time the first floating occurs, the angle of rotation of the placement plane caused solely by the movement of the roller system is called a first angle; during each time the second floating occurs, the angle of rotation of the placement plane caused solely by the movement of the roller system is called a second angle; the size of the first angle is equal to the size of the second angle.

[0152] It can be understood that "the rotation angle of the placement plane caused solely by the movement of the roller system during each occurrence of the first floating" and "the rotation angle of the placement plane caused solely by the relative movement between the two rollers during each occurrence of the first floating" are equal in size but opposite in direction.

[0153] It can be understood that "the rotation angle of the placement plane caused solely by the movement of the roller system during each occurrence of the second floating" and "the rotation angle of the placement plane caused solely by the relative movement between the two rollers during each occurrence of the second floating" are equal in size but opposite in direction.

[0154] Furthermore, a roll gap floating method for a double-roll thin strip is provided, wherein the first angle and / or the second angle is in the range of 0.01 to 0.1 degrees.

[0155] It should be noted that “the first angle and / or the second angle are in the range of 0.01 to 0.1 degrees” includes the end values ​​of 0.01 and 0.1 degrees; that is, in the patent application document of the present invention, unless otherwise specified, “in the range of… to…” includes the end values.

[0156] Furthermore, a roll gap floating method for a double-roll thin strip is provided, wherein the first angle and / or the second angle is in the range of 0.1 to 1 degree.

[0157] Furthermore, a roll gap floating method for a double-roll thin strip is provided, wherein the first angle and / or the second angle is in the range of 1 to 10 degrees.

[0158] Furthermore, a roller gap floating method for a double-roll thin strip is provided, wherein during the first floating and / or the second floating, the placement plane does not change, and the placement plane coincides with the reference plane.

[0159] It is understandable that if Fig.10 As shown, taking the horizontal equal-diameter twin-roll casting machine as an example, the reference plane is plane Ψ0, and the first floating and / or the second floating occurs during a certain period of time in the preparation process or during the entire preparation process; during the process of the first floating and / or the second floating, the placement plane always coincides with plane Ψ0.

[0160] It can be understood that "the placement plane coincides with the reference plane" is the most important application mode.

[0161] Furthermore, in a roller gap floating method for a double-roll thin strip, during the first floating or the second floating, the placement plane does not change; and the placement plane does not overlap with the reference plane.

[0162] It is understandable that if Fig.10 As shown, taking the horizontal equal-diameter twin-roll casting machine as an example, the reference plane is plane Ψ0. During a certain period of time in the preparation process, due to the movement of the roller system and / or the floating of the roller gap, the placement plane is plane Ψ1; plane Ψ0 and plane Ψ1 are two non-overlapping planes; then, the first floating and / or the second floating occur; during the process of the first floating and / or the second floating, the placement plane is always plane Ψ1.

[0163] It is understandable that for Figure 4 The zero-angle roll gap shown in the figure has bidirectional floating: when the two rolls approach each other, the floatation of the roll gap causes the molten pool pressure to increase; when the two rolls move away from each other, the floatation of the roll gap causes the molten pool pressure to decrease.

[0164] It should be noted that in the patent application document of the present invention, when the inner product of the floating speed and the preparation speed is less than zero, the floating of the roll gap causes the molten pool pressure to increase; when the inner product of the floating speed and the preparation speed is greater than zero, the floating of the roll gap causes the molten pool pressure to decrease.

[0165] It should be noted that, in the patent application document of the present invention, “the inner product of the floating speed and the preparation speed is less than zero” can be used to replace the following: Figure 4 The "two rollers approach each other" in the zero-angle roll gap bidirectional floating shown in the figure; "the inner product of the floating speed and the preparation speed is greater than zero" can be used to replace the following: Figure 4 The "two rollers move away from each other" in the zero-angle roll gap bidirectional floating shown in the figure; the technical solutions proposed in the patent application document of the present invention are as follows Figure 4 The traditional method shown is more efficient, however, the mathematical control model of the technical solution proposed in the patent application document of the present invention is much lower than that of Figure 4 The traditional method shown.

[0166] It can be understood that, in summary, in the patent application document of the present invention, when elaborating on the proposed technical solution, the use of the limitations "each time the first floating occurs, the first inner product is always less than zero; or, each time the first floating occurs, the first inner product is always greater than zero" and / or "each time the second floating occurs, the second inner product is always less than zero; or, each time the second floating occurs, the second inner product is always greater than zero" is fully reasonable and of practical significance.

[0167] It should be noted that the technical solution proposed in the patent document of the present invention is different from asynchronous rolling (or differential rolling); the driving force of asynchronous rolling is still pure shear force, and the shear force is transmitted by viscosity; however, the technical solution proposed in the patent document of the present invention utilizes the relative movement between the two rollers to generate a normal driving force, and the transmission of the normal driving force has nothing to do with viscosity.

[0168] It should be noted that, at present, the relevant equipment involved in the technical solution proposed in the patent of this invention does not exist in the industry; however, the current level of science and technology is sufficient to realize the manufacture of relevant equipment; that is to say, the technical solution proposed in the patent of this invention can be realized without a doubt.

[0169] The advantages of the method proposed in the patent application document of the present invention include: In the process of roll gap fixed opening and synchronous floating, the process parameters of roll gap floating (including: amplitude; floating speed) can be set arbitrarily according to actual needs. The setting of the process parameters of roll gap floating is only limited by equipment conditions. In the process of roller gap fixed opening and synchronous floating, the two rollers and the side sealing device always remain stationary relative to the ground, which can theoretically completely eliminate the influence of the roller gap floating process on the side sealing device, thereby providing an infinite process parameter range in theory; During the one-way floating of the roll gap, the casting force changes in one direction; when the inner product of the floating speed and the preparation speed is always less than zero, a normal driving force can be applied to the semi-solid material in the molten pool. The normal driving force is independent of viscosity. This can enhance process stability and / or improve billet quality (for example, reduce or eliminate cracks in Cu-9Ni-6Sn alloy). During the floating process of the roll gap, the roll gap does not change, and in theory, the uniformity of the thickness of the blank can be guaranteed. In the process of preparing metal materials with a wide two-phase region by using the roll gap fixed-single-direction-synchronous floating method, the shear thinning behavior and / or thixotropic behavior of the semi-solid metal can be more effectively suppressed; In the process of preparing metal materials with a wide two-phase region by using the roll gap fixed-single-direction-synchronous floating method, segregation, especially macro segregation, can be suppressed; During the process of one-way floating of the roll gap, the casting and rolling force changes in one direction; when the inner product of the floating speed and the preparation speed is always greater than zero, for materials with a narrow two-phase region, reducing the molten pool pressure can promote the formation of the kiss angle, and the semi-solid material in the kiss angle area is used to prevent the pressure in the molten pool from connecting with the unsolidified core of the billet out of the molten pool, avoiding billet defects such as "ridges", "snake eggs" and "egg-filled pancakes"; For materials with a wide two-phase region, when the inner product of the floating speed and the preparation speed is always less than zero, a normal driving force that is independent of the viscosity of the semi-solid metal can be applied to the molten pool to keep the total driving force stable, which can promote the renewal of the Kiss angle material, inhibit the rapid development of the Kiss angle, reduce the pressure peak at the collapse of the long-range shear thinning interface, and prevent various process stability problems such as side sealing plate leakage, side sealing plate damage, tape jamming, tape breakage, cracks, edge waves, etc. caused by excessively high molten pool pressure peaks, and shortened service life of key components; Reduce the excessive vibration of the twin roll caster caused by the collapse of the overdeveloped shear thinning interface; The roller gap floating is realized by the alternating motion of the two rollers, so as to further improve the structure and performance of the green body, for example, refine the grains, and for example, inhibit segregation; By controlling the total driving force to be stable, the roller diameter can be further increased, thus significantly increasing the output; When the roll gap floating is always used to increase the molten pool pressure, the heat transfer performance of the roll body can be enhanced and the billet output can be increased; Increase the contact pressure between the roller working surface and the cast material, reduce the heat transfer resistance to increase the heat transfer efficiency, and increase the billet output; When the roll gap is floated to increase the molten pool pressure, "scratches" on the billet surface can be avoided (scratches are of great significance for the preparation of aluminum and its alloys). This is because the shear driving force is reduced due to the addition of the shear independent driving force, which can effectively avoid the slip between the roll surface and the cast material. Avoiding "scratches" is crucial for the preparation of aluminum alloy billets. During the roll gap fixed opening and synchronous floating process, due to the action of the roll system movement, the two roll bodies are always stationary relative to the ground, minimizing the disturbance of the roll gap floating and / or roll system movement on the melt in the molten pool; The roller gap fixed opening-synchronous floating method is used, and the roller body and the side sealing device always remain relatively still, so that the process parameter window is expanded, the service life of the contact side sealing device can be extended, and the production cost can be reduced; The alternating motion of the two rollers is conducive to the symmetrical distribution of the green body structure; Significantly increase the output of twin-roll casting of non-ferrous metals (e.g., aluminum and its alloys). For aluminum and its alloys, theoretically, the output can be increased several times or even dozens of times, according to conservative estimates; When the first float and the second float are combined arbitrarily, the mathematical model used for real-time control can be simplified; When roll gap floating is used to increase the melt pool pressure, it can reduce the occurrence of micron-sized pores in non-ferrous metals, especially aluminum and its alloys; the causes of these pores include hydrogen evolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0170] Figure 1 Shown is a schematic diagram of the traditional understanding of the solidification shell development process in the field.

[0171] Figure 2 The figure shows the actual experimental results obtained by implementing the Kiss angle measurement method.

[0172] Figure 3 Shown is a theoretical schematic diagram of the experimental results obtained by implementing the kiss angle measurement method.

[0173] Figure 4 Shown is a schematic diagram of a zero-angle roll gap bidirectional floating method in the prior art.

[0174] Figure 5 Shown is a schematic diagram of a vertical roller gap bidirectional floating method in the prior art.

[0175] Figure 6 Shown is a schematic diagram of the inclined roller gap bidirectional floating method in the prior art.

[0176] Figure 7 Shown is a schematic diagram of a fixed-gap roll gap bidirectional floating method in the prior art.

[0177] Figure 8 Shown is a schematic diagram of the side sealing device before use.

[0178] Fig. 9 The figure shows a schematic diagram of the side sealing device after use with a sloped surface.

[0179] Fig.10 Shown is a schematic diagram for explaining the placement plane, reference plane, first roll body, second roll body, Nip point, first roll axis, second roll axis, preparation direction, reference speed, reference direction and reference line of a horizontal equal-diameter twin-roll thin strip caster in different states.

[0180] Fig.11 It is a schematic diagram showing the first floating process of the embodiment 1 of the present invention.

[0181] Fig.12 It is a schematic diagram showing the second floating process of the embodiment 1 of the present invention.

[0182] The corresponding relationship between the figure numbers in the following figures is as follows: 1. First roller body, 2. Second roller body, 3. Roll gap, 4. Long-range shear thinning interface, 5. Molten pool, 6. Flow distribution device, 7. Blank body, 8. Reference plane, 9. Direction of gravity. DETAILED DESCRIPTION

[0183] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0184] The present invention will now be described in further detail with reference to the accompanying drawings.

[0185] For the sake of convenience, please combine Fig.10 In the patent application document of the present invention, take any plane Ω, the plane Ω is perpendicular to the first roller axis; the roller axes of the first roller body 1 and the second roller body 2 are respectively called the first roller axis and the second roller axis; the minimum distance between the first roller body 1 and the second roller body 2 is called the roller gap 3; the midpoint of the roller gap 3 is called the Nip point; in a natural state, the plane where the first roller axis and the second roller axis are located is the reference plane 8; in a natural state, the normal of the reference plane 8 passing through the Nip point is called the reference line; in a natural state, the intersection points of the first roller axis and the second roller axis with the plane Ω are point O1 and point O2 respectively.

[0186] Embodiment 1: Embodiment 1 of the present invention discloses a roll gap floating method for a double-roll thin strip, such as Figures 11 to 12 shown.

[0187] Embodiment 1 of the present invention adopts a horizontal equal-diameter twin-roll casting machine, and therefore, the reference direction is the same as the gravity direction 9 .

[0188] like Fig.11 As shown, during the first floating process, the first roller body 1 rotates clockwise around the second roller axis without stopping, and at the same time, the roller system rotates counterclockwise around the second roller axis; the angular velocity of the first roller body 1 around the second roller axis is ω1, and the angular velocity of the roller system around the second roller axis is ω2; ω1 and ω2 are both vectors, ω1=-ω2; the placement plane is always located at the reference plane 8; during the first floating process, the inner product of the floating speed and the preparation speed (or, the first inner product) is always less than zero, so as to increase the pressure in the molten pool 5, thereby providing additional shear-independent driving force for the semi-solid metal in the molten pool 5; since the first roller body 1 and the second roller body 2 are always stationary relative to the ground, the size of ω1 can be arbitrarily set according to actual needs, thereby theoretically providing an infinite process parameter range.

[0189] like Fig.12As shown, during the second floating process, the second roller body 2 rotates counterclockwise around the first roller axis without stopping, and at the same time, the roller system rotates clockwise around the first roller axis; the angular velocity of the second roller body 2 around the first roller axis is ω'1, and the angular velocity of the roller system around the second roller axis is ω'2; ω'1 and ω'2 are both vectors, ω'1=-ω'2; the placement plane is always located at the reference plane 8; during the second floating process, the inner product of the floating speed and the preparation speed (or, the second inner product) is always less than zero, so as to increase the pressure in the molten pool 5, thereby applying a normal driving force that is independent of viscosity to the semi-solid material in the molten pool 5; since the first roller body 1 and the second roller body 2 are always stationary relative to the ground, the size of ω'1 can be arbitrarily set according to actual needs, thereby theoretically providing an infinite process parameter range.

[0190] In Example 1 of the present invention, during the preparation process, the first floating and the second floating occur sequentially and repeatedly.

[0191] It can be understood that “the first floating and the second floating occur sequentially and repeatedly” means: “one first floating” and “one second floating” occur sequentially and repeatedly.

[0192] During each first floating process, the angle of rotation of the placement plane caused solely by the movement of the roller system is called the first angle; during each second floating process, the angle of rotation of the placement plane caused solely by the movement of the roller system is called the second angle.

[0193] In Embodiment 1 of the present invention, the size of the first angle is equal to the size of the second angle.

[0194] It should be noted that a person skilled in the art can directly and without doubt determine that both the first angle and the second angle are less than 360 degrees; in fact, both the first angle and the second angle cannot exceed 90 degrees, and even, both the first angle and the second angle may not exceed 15 degrees.

[0195] Optionally, in other embodiments, "multiple first floats" and "one second float" occur sequentially and repeatedly; or, "one first float" and "multiple second floats" occur sequentially and repeatedly; or, "multiple first floats" and "multiple second floats" occur sequentially and repeatedly; or, "multiple first floats" and "multiple second floats" occur sequentially and repeatedly; or, "multiple first floats" and "multiple second floats" occur in any combination for more complex real-time control.

[0196] Optionally, the first angle is arbitrary, and\or the second angle is arbitrary.

[0197] Optionally, the first angle and / or the second angle is in the range of 0.01 to 0.1 degrees.

[0198] Optionally, the first angle and / or the second angle is in the range of 0.1 to 1 degree.

[0199] Optionally, the first angle and / or the second angle is in the range of 1 to 10 degrees.

[0200] In the first embodiment of the present invention, the occurrence frequency of the first floating and / or the second floating is in the range of 0.1 to 5 Hz.

[0201] Optionally, the occurrence frequency of the first floating and / or the second floating is in the range of 0.01 to 10 Hz.

[0202] Optionally, in a preparation process, out of consideration of actual process requirements, any of the following methods occurs: A first float and a second float occur, wherein the first float and the second float are any combination; One first float and multiple second floats occur, wherein the one first float and the multiple second floats are any combination; A plurality of first floats and a plurality of second floats occur, wherein the plurality of first floats and the plurality of second floats are any combination.

[0203] Optionally, in another embodiment, during the first floating process, the inner product of the floating speed and the preparation speed (or, the first inner product) is always greater than zero; during the second floating process, the inner product of the floating speed and the preparation speed (or, the second inner product) is always greater than zero; thereby reducing the pressure in the molten pool 5.

[0204] It can be understood that “one preparation process” is a continuous process; in this “continuous process”, the composition of the blank 7 does not undergo a predetermined change.

[0205] It is understandable that the “end of the preparation process” may be caused by the “end of the process” or by a set change in the composition of the prepared green body 7 .

[0206] It is understandable that a person of ordinary skill in the art can directly and without doubt know that "the process is over"; "the process is over" can be determined by "the blank 7 is no longer removed from the molten pool 5"; "the process is over" can also be determined by "no more material for preparing the blank 7 is added to the molten pool 5".

[0207] It is understandable that a person skilled in the art can directly and without doubt know that "the composition of the prepared blank 7 undergoes a set change"; in one process, two or more blanks 7 with different compositions can be prepared. For example, in one process, a blank 7 with silicon steel composition is first prepared, and after the preparation of the blank 7 with silicon steel composition is completed, the composition of the molten metal entering the molten pool 5 is changed to prepare a blank 7 with stainless steel composition, until the process is completed; the "blank 7 with silicon steel composition" and the "blank 7 with stainless steel composition" are blanks 7 with different compositions; in this process, two preparation processes occur.

[0208] It can be understood that the above-mentioned "one process" includes two "preparation processes"; one "preparation process" refers to "a process in which the composition of the primary blank 7 does not change"; in the above-mentioned "one process", the preparation of the "blank 7 with silicon steel composition" and the "blank 7 with stainless steel composition" are completed successively, which belongs to two preparation processes; that is to say, at least "one preparation process" occurs in the "one process".

[0209] It can be understood that "two or more blanks 7 with different compositions can be prepared in one process" is to avoid the cost of replacing the flow distribution device 6 and / or the side sealing device, and to improve equipment utilization so as to reduce production costs as much as possible.

[0210] It can be understood that, in a preparation process, the first inner product may always be greater than zero, or may always be less than zero.

[0211] It should be noted that, under normal circumstances, when liquid metal is used to directly prepare a blank 7 with a metal component, there are some different opinions in the field about the upper limit of the opening of the roll gap 3; however, the opening of the roll gap 3 mentioned in the public information that the inventors can find at present is all below 8 mm; in fact, the upper limit of the opening of the roll gap 3 attempted in industrial practice, under normal circumstances, when preparing steel materials, does not exceed 3 mm; the diameter of the roll body is more than 400 mm; therefore, whether the opening of the roll gap 3 is "8 mm" or "3 mm", it is much smaller than the diameter of the roll body.

[0212] It is understandable that in the present invention patent 1, the drawing scale of the first roller body 1, the second roller body 2, the roller gap 3, etc. is obviously different from the actual situation. Only in this way can the characteristics of the technical solution mentioned in the patent application document of the present invention be clearly demonstrated.

[0213] It should be noted that even without the above description of the drawing scale, a person of ordinary skill in the art can directly and unambiguously understand the schematic diagrams involved in the patent application document of the present invention.

[0214] In the patent application document of the present invention, the embodiment adopts a horizontal equal-diameter twin-roller thin strip caster, which is only one form of twin-roller thin strip caster. There are many forms of twin-roller thin strip casters, and there are many classification methods: according to the difference in roller diameter, twin-roller thin strip casters include equal-diameter type, different-diameter type, and variable-diameter type; according to the placement of the two rollers, twin-roller thin strip casters include horizontal type, inclined type, and vertical type; according to the method of leading out the blank, twin-roller thin strip casters include leading out along the direction of gravity, leading out at an angle less than 180 degrees from the direction of gravity, and leading out in a direction completely opposite to the direction of gravity. The variable-diameter twin-roller casting and rolling process belongs to the field of twin-roller thin strips. The variable-diameter twin-roller thin strip caster refers to a twin-roller thin strip caster in which the diameter of at least one of the two rollers changes along the direction of its roller axis. The variable-diameter twin-roller thin strip process can be used to prepare coating materials such as multi-layer tubes, multi-layer rods, and multi-layer thin plates.

[0215] It should be further noted that any type of twin-roll thin strip casting machine can use the embodiments in the patent application document of the present invention.

[0216] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the specification of this application, ordinary technicians can still modify or replace the specific implementation mode of the present invention with equivalents, but these modifications or changes do not deviate from the scope of protection of the pending claims of the present application.

Claims

1. A roll gap floating method for a twin-roll thin strip, wherein a roll system is movably arranged on a twin-roll thin strip casting machine as a whole, and the roll system comprises a first roll body and a second roll body which are arranged opposite to each other and are used to prepare a blank; the roll axis of the first roll body is called the first roll axis, and the roll axis of the second roll body is called the second roll axis; the plane where the first roll axis and the second roll axis are located is called the placement plane of the roll system; It is characterized in that The method comprises the steps of: First floating: the second roller body is stationary relative to the ground, and the first roller body is controlled to rotate around the second roller axis without stopping. At the same time, the roller system is controlled to rotate around the second roller axis, and the placement plane is always stationary relative to the ground; Second floating: the first roller body is stationary relative to the ground, and the second roller body is controlled to rotate around the first roller axis without stopping. At the same time, the roller system is controlled to rotate around the first roller axis, and the placement plane is always stationary relative to the ground; In one preparation process, the first floating occurs at least once, and the second floating occurs at least once.

2. A roll gap floating method for a double-roll thin strip according to claim 1, Features: The minimum distance between the first roller body and the second roller body is called the roller gap; the midpoint of the roller gap is called the Nip point; the moving speed of the blank at the Nip point is called the preparation speed; the moving speed of the Nip point caused by the relative movement between the first roller body and the second roller body is called the floating speed of the Nip point; during each occurrence of the first floating, the inner product of the floating speed and the preparation speed is called the first inner product; during each occurrence of the second floating, the inner product of the floating speed and the preparation speed is called the second inner product; During each occurrence of the first floating, the first inner product is always less than zero; and during each occurrence of the second floating, the second inner product is always less than zero.

3. A roll gap floating method for a double-roll thin strip according to claim 2, Features: During each occurrence of the first floating, the first inner product is always greater than zero; and during each occurrence of the second floating, the second inner product is always greater than zero.

4. A roll gap floating method for a double-roll thin strip according to claim 1, Features: The occurrence frequency of the first floating and / or the second floating is in the range of 0.1 to 5 Hz.

5. A roll gap floating method for a double-roll thin strip according to claim 1, Features: The occurrence frequency of the first floating and / or the second floating is in the range of 0.01 to 10 Hz.

6. A roll gap floating method for a double-roll thin strip according to claim 1, Features: During a preparation process, any of the following occurs: The first floating occurs once and the second floating occurs once, wherein the first floating occurs once and the second floating occurs once in any combination; The first floating occurs once and the second floating occurs multiple times, wherein the first floating occurs once and the second floating occurs multiple times in any combination; A plurality of the first floating and a plurality of the second floating occur, wherein the plurality of the first floating and the plurality of the second floating are any combination.

7. A roll gap floating method for a double-roll thin strip according to claim 1, Features: The first floating and the second floating occur sequentially and repeatedly.

8. A roll gap floating method for a double-roll thin strip according to claim 1, Features: During each occurrence of the first floating, the angle of rotation of the placement plane caused solely by the movement of the roller system is called the first angle; during each occurrence of the second floating, the angle of rotation of the placement plane caused solely by the movement of the roller system is called the second angle; the size of the first angle is equal to the size of the second angle.

9. A roll gap floating method for a double-roll thin strip according to claim 8, Features: The first angle and / or the second angle are in the range of 0.01 to 10 degrees.

10. A roll gap floating method for a double-roll thin strip according to claim 1, Features: During the first floating or the second floating, the placement plane does not change, and the placement plane coincides with the reference plane.

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