CZ20032247A3 - Method and apparatus for applying a coating composition to rolls of a metal strip continuous casting machine and continuous casting machine per se and control method thereof - Google Patents

Abstract

The invention concerns a method for refractory dressing of rolls of a machine for continuous casting between rolls which consists in applying a mould dressing product containing a mould dressing agent, such as graphite, and in adjusting the mould dressing product composition while it is being applied on the rolls. The invention also concerns a device for refractory dressing of rolls of a machine for continuous casting between rolls comprising means for applying a mould dressing product and means for adjusting the composition of the mould dressing product while it is being applied on the rolls. The invention enables to control the amount and the distribution of the mould dressing product on the surface of the rolls.

Description

METHOD AND APPARATUS FOR APPLYING COATING COAT ON THE CYLINDERS OF A FLAT CASTING DEVICE OF A METAL BELT

Technical field

The invention relates to the continuous casting of metal strips between rolls, in particular strips of aluminum or an aluminum alloy. More particularly, it relates to a method and apparatus for applying a coating coating during casting.

BACKGROUND OF THE INVENTION

Continuous casting between rolls is a process well known for extracting metal strips from a liquid metal source. Typically, the liquid metal is injected into the gap separating the two rotating metal cylinders, solidifies in contact with the cylinders and exits therefrom in the liquid state in the form of a strip.

Without special precautions, the solidifying metal generally adheres to the surface of the rollers, which leads to deterioration of the strip quality or even to a halt in the casting process. In order to eliminate this bonding phenomenon, which is the more pronounced the higher the productivity of the apparatus, it is known to coat the working surface of the rollers by spraying a liquid coating substance (also called a lubricant) with nozzles or guns. The coating is often a mixture of water and graphite particles. The coating is normally applied continuously, i.e. the working surface of the roll is substantially continuously coated with a coating.

The known coating devices comprise one or more rollers for spraying paint which can be solid or movable.

• · ··· · ········ · ·

Patent applications FR 2,498,099 (corresponding to U.S. Pat. No. 4,501,315) and FR 2,621,839 (corresponding to U.S. Pat. No. 4,892,133) disclose an adjustable discharge spout coating apparatus comprising spray distribution ramps provided with spraying means, mounted linearly along the rollers.

International Patent Application WO 95/09707 discloses a paint spraying device provided with paint spray nozzles arranged along the rollers and grouped by zones, each zone being fed separately with the coating agent depending on the width of the metal strip. A portion of the nozzles can be moved in an oscillating motion parallel to the axis of the rollers.

As part of a long-term effort to develop machines and devices for continuous casting of metal strips between rolls, the Applicant has stated that the known methods and devices for continuous casting do not make it possible to eliminate the problems of gluing under all conditions of industrial production of metal strips. The Applicant has therefore sought a solution for improving coatings for continuous casting rolls of metal strips.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION The present invention provides a method of coating the rolls of a roll-to-roll continuous casting machine in which at least one coating is applied, such as a graphite suspension, characterized in that it comprises adjusting the composition of the coating during roll coating.

The invention also provides a method of continuously casting a co-molded cast iron. ··

The invention also relates to roll-to-roll bands comprising a method of applying a coating according to the method of the invention.

The invention also provides a roll coating apparatus for use on a continuous roll-casting machine comprising means for applying at least one coating material and comprising means for adjusting the composition of said coating material during application thereto. war.

Further, the invention provides a machine for continuously casting metal strips between rollers provided with a coating device according to the invention.

The present invention also provides a method for controlling a continuous strip casting machine, wherein at least one coating composition comprising a coating agent such as graphite is applied to the rolls, the method comprising adjusting the composition of the coating composition during coating onto the rolls. Said adjustment is preferably carried out under operating conditions of said machine.

The continuous casting may be horizontal, inclined relative to the horizontal direction or vertical (ascending or descending).

In order to achieve optimum efficiency of the coating, the Applicant has sought to control the amount and distribution of the coating coating applied to the working surface of the rollers. During these experiments, it was stated that, contrary to what is normally accepted, the outflow was a change in discharge.

Not only the amount of spraying agent used to vary the amount of coating applied to the rollers, but also the distribution of the coating applied to their working surface, resulting in particular in uncontrolled variations in the coating efficiency, which is related to the stability of the casting machine and the quality of the belt. In particular, the Applicant has found that variations in the flow rate of the coating coating sprayed onto the roller working surface by the spraying agent can cause variations in the coating distribution within the spray cone or streams and the impact surface, as a rule variations in coating composition do not significantly alter this distribution.

In order to solve the problem to which the invention was based, the inventors came up with the idea of adjusting the coating composition during application, which allows to adjust the amount of coating material deposited on the surface of the roll while reducing the application disparities. The coating coating may be a suspension, a solution or a mixture of both.

BRIEF DESCRIPTION OF THE DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side view of a continuous strip casting machine having prior art coating compositions; FIG. a device for applying a coating to a continuous casting device between rollers according to the prior art, FIG. 3 a schematic illustration of a preferred embodiment of a device for applying a coating

Fig. 4 is a schematic diagram of a variant of a part of a coating device for applying a continuous coating between rollers according to the invention, Fig. 5. 6 shows a diagram of the effect of varying the coating paint side-by-side spraying agent on the distribution of the coating paint on the cylinder surface, Fig. 6 diagram of the effect of varying the coating paint side-by-side spraying agent on the distribution of the coating paint on the cylinder surface in the case of large Fig. 7 is a schematic side view of a continuous casting machine between rollers provided with coating coating means according to a possible embodiment of the invention; Fig. 8 is a schematic and simplified top view of a continuous casting machine between rollers provided with means; and Figure 9 is a schematic and simplified top view of a continuous casting machine between rollers provided with coating coating means according to a possible embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

As shown in Figure 1, the continuous casting device between rollers typically comprises two horizontal rollers ΙΑ, IB and injector 2. The rollers ΙΑ, IB are typically of metal and generally have the same diameter. The axes of rotation A, B of the rollers are substantially parallel to each other. The rollers are separated from each other by a gap 13 and are capable of rotating in opposite directions.

On the one hand, liquid metal 3 is introduced into the gap 13 by means of an injector 2, which on the other side exits in a solid state in the form of a strip 4 having a nominal thickness E 0. which is ·· • · ·· ί 9 9 9 9

999 · ·

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The surface 10 of the rolls is continuously cooled, typically by means of a cooling fluid circulating inside the rolls.

The casting is the so-called horizontal casting, when the connecting line A-B of the centers of cylinders IA and IB is substantially vertical, the inclined casting if the axis A-B is inclined relative to the vertical and the so-called vertical casting when the axis A-B is substantially horizontal.

The roll-to-roll continuous casting machine is normally provided with coating application means which typically comprise spray coating means 24, coating support means 7, 8, 8 for supporting said spraying means, coating coating source 22, pipe mixer 23, 21 for guiding the coating paint 24 and means 20 for controlling the flow of the coating paint. The coating coating source 22 is typically a tank with a capacity of about 100 to 200 liters.

According to the invention, the method of applying a coating to the rollers ,Α, IB of a continuous casting machine 1 comprises applying at least one coating coating 24 to the rolls, wherein the coating comprises a coating agent and a carrier fluid and characterized by adjusting the composition of said coating coating 24 during roll application.

The invention is based on the idea of varying the composition of the coating composition and in order to eliminate fluctuations in the size of the streams and to distribute the coating composition within the spray cone or streams 9, 91, 92 and onto the impact surface 100, 101, 102. • · · · · · · · · ·

-7 (discharge flow rate) from the spray means 5, 51, 52.

The coating agent is preferably graphite, typically in the form of micron particles. The carrier fluid is preferably water. The graphite is in suspension in a carrier liquid, optionally in a colloidal form, at a concentration of typically from 0.2 to 4% by weight.

In a preferred embodiment of the invention said adjustment comprises adjusting the proportion of the coating agent contained in the coating coating agent, i.e. the coating agent concentration of the coating coating agent. It is thus possible to vary the amount of coating agent sprayed onto the roller by varying the proportion of coating agent in the coating coating without changing the flow rate (flow rate per flow) of the spray means. In this case, the proportion of coating agent increases when a larger amount of coating agent is to be sprayed onto the roller surface 10, otherwise the proportion is reduced.

Preferably, the adjustment comprises a dilution composition of the coating agent concentrate in the carrier fluid. The concentrate may be a mother suspension, a concentrated solution or a mixture thereof. The concentrate is preferably selected from concentrated suspensions of graphite, boron nitride, colloidal silica, magnesium oxide, organic substances (such as organic oils or polyesters) or mixtures thereof. Typically, it is possible to use a mother slurry which is a concentrate of graphite particles in a gel suspension, with a graphite content typically from 20 to 30 wt%. The carrier fluid is generally water. The proportion of mother suspension added to the carrier fluid is typically from 1 to 8%.

In practice, it may be advantageous that the method of the invention also comprises adjusting the flow rate of the coating coating to achieve flow stability over time, particularly between the time the guns are adjusted relative to the rollers, outside the casting, and during casting.

The adjustment of the composition can be done in feedback depending on the measurements made on the casting machine 1 (typically by means of a control loop) and / or automatically. Said measurements are typically measurements selected from optical measurement, laser measurement, infrared measurement, vibration measurement or mechanical voltage measurement. For example, the amount of coating agent present on the surface of the rollers 10 can be determined by a detector (such as an optical detector, laser system, camera or infrared detector) that generates a signal that can be used in feedback to adjust the coating composition composition. Said adjustment of the composition may thus correspond to regulation. The method according to the invention can be incorporated into the process of controlling the continuous casting machine between rolls.

The coating coating device is suitable for carrying out the coating method according to the invention.

The paint application means preferably comprises means 20 for controlling the discharge amount of spray means 5, 51, 52, such as a volumetric pump.

Pipes 6, 21 may be of different materials, compati-944 44 • 4 4 4

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4 4

4 4

4444 44 • 44 4 • 44 444 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 44 When the spraying means is movable, the conduit part 6 is preferably flexible.

The coating compositions may be located at various locations around the periphery of the rollers. However, they are preferably located on the outlet side, i.e. on the metal strip side, so that they do not come into contact with the liquid metal, which could cause an explosion hazard.

In the very common case where the coating paint contains a carrier fluid such as water and a solid coating agent such as graphite, the coating compositions may also contain active or passive means, such as a stirrer 38 or slide 39, to homogenize the coating. . Optionally, the coating coating compositions of the present invention may comprise means 38 to keep the coating agent particles in suspension.

In the preferred embodiment of the invention shown in Figure 3, the coating composition adjusting means comprises a mixer 40, a coating agent supply 41, a coating agent supply control means 32, and a carrier fluid supply 30. The control means 32 allows to control and control the amount of coating agent that is fed to the mixing 40 and which is applied to the rollers by means of applying the coating coating. For example, the control means 32 may comprise a metering pump.

The mixer 40 may also be a venturi device, buffer tank or chamber. The mixer 40 preferably has

Φ φ Φ φ • · · · · · · · • • • • • • • • • • • φ φ • • • • • • φφ φ very small capacity (for example 1 to 2 liters), which makes it possible, in particular, to rapidly change the concentration of the coating agent contained in the coating coating. The mixer 40 may be common to multiple spray means.

4 shows two embodiments of said adjusting means. In the embodiment of Fig. 4a, said adjusting means comprise a reservoir 34 adapted to receive the concentrate 35, a coating agent supplying means 32, piping means 31, 33, a carrier fluid supply 30, a buffer tank 36 adapted to receive the coating 24, a mixing zone 37 and agitator 38. In the embodiment of FIG. 4b, said adjusting means comprise a reservoir 34 adapted to receive the concentrate 35, a coating agent supply control means 32, piping means 31, 33, a carrier fluid supply 30, a chamber 36 adapted to receive the coating material. 24, mixing zone 37, damper 39 and stirrer 38.

The Applicant has found that diluting the coating agent concentrate in the carrier fluid in the mixer 40, especially when it has a low capacity, can allow the removal of the coating agent sedimentation problems that are often observed in known devices (which typically work batchwise using large tank 22) capacity (typically 100 to 200 liters) and which cause the actual coating composition to deviate from the nominal value. The use of one or more small capacity mixers 40 also allows to reduce their volume and thus the size of the casting devices. It also allows for simplified operation.

-11 φ · · φ · φ · φ φ φ φ · · φ φ φ φ φ • φ φ φ φ φ φ φ φ φ φ φ • Φ φφ

When the coating agent is in the form of a concentrate 35 capable of being diluted with a carrier fluid, the coating agent supply 41 preferably comprises a tank 34 from which the mixer 40 can be regulated in a controlled manner.

The means (30-41) for adjusting the composition of the coating composition may comprise an adjusting device 42 which is preferably separate, removable and / or demountable, which facilitates its maintenance.

The coating application device may comprise means for feedback control of said composition adjustment depending on the measures performed on said casting machine, for example by means of a control loop. It may also comprise means for automatically controlling said composition adjustment.

Spray means 5, 51, 52 are typically selected from the group consisting of nozzles and guns. The coating means may comprise a single roller spraying agent 5 (FIG. 1) or multiple roller spraying agents 51, 52 (FIGS. 7 and 9). In the latter case, the spraying means may lie one above the other (as shown in FIG. 7) or distributed along the cylinder (as shown in FIG. 9). The coating means may also include means for moving the spray means along the roller, typically by an oscillating or reciprocating movement between one end 11 and the other end 12 of the roller.

According to a preferred variant of the invention said coating compositions comprise a spraying agent 5 for spraying

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AAA, IB, and means 80-84 for moving said spray means 5 along each cylinder, typically in a reciprocating motion.

According to a further variant of the invention said coating means comprise at least two spraying means 51, 52 for each roller ΙΑ, IB, said spraying means being joined together, and means 80 to 84 for moving each of said assemblies along each roller, typically reversible. movement. Preferably, the spray means of each of said rollers are superimposed, as shown in FIG. 7, when the tendency to produce wide-width belts is observed (which normally becomes difficult due to the limited maximum speed of the spray means).

The transfer means 80 to 84 typically comprise a movable carrier or trolley 80, a rail 81 and drive means 82, 83, 84 as an engine. Advantageously, these transfer means 80 to 84 permit the movement of said spray means by reciprocating along an axis parallel to the cylinder axis A, B.

According to a further preferred variant of the invention said coating means comprise at least two spraying means 5 per roller and said spraying means being arranged on lines substantially parallel to the axis A, B of each of said rollers ΙΑ, IB. Spray means s typically lie equidistant.

The orientation of the spray means may be fixed or

-13 • 9 «9 · ♦ 9 • 9 9 • 9 9 99 99 999 99 9 9 9 9 9 9 9 9 9 4 9

99 · * · «·· changeable. The device according to the invention may also comprise means for oscillating at least one of the spray means relative to the specified axis, which makes it possible to increase the associated impact surface of the spray means and possibly reduce their number. The oscillation axis is preferably vertical.

The invention is particularly advantageous when at least two spraying means are used per cylinder. In such cases, however, the overlapping of the spray cones 9, 91, 92 and the impact surfaces 100, 101, 102 may cause significant variations in the overall distribution of the coating agent from the multiple spray means. For example, as shown schematically in FIG. 5, where D denotes the surface density of the coating agent, the total impact area of two adjacent spray means can be subjected not only to radial density variations, as is the case with a single spray agent, but also to very large density variations. in the contact area between the spray cones and the impact surfaces, even though the coating may be close to the nominal value N in the areas where the impact surfaces do not overlap.

Fig. 5a corresponds to the case where both streams form a relatively tight angle with respect to the optimum desired value. The overlap between the spray cones and the two impact surfaces in this case is very low or zero, resulting in areas E of reduced coating deposition with respect to the nominal value N.

Fig. 5b corresponds to the case where both streams form an angle that is relatively open relative to the desired optimum value. Overlap between spray cones and both impact cones

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In this case, the areas are not negligible or are relatively large, leading to areas of excessive deposition with respect to the nominal value of N.

Fig. 6 shows that a similar effect may occur even though the overlap regions between the impact surfaces are very large. In this latter case, the amount of paint applied can vary greatly in some areas and moves from insufficient deposition in certain areas T when the angle of the streams is relatively close to the desired optimum value (Fig. 6a), to excessive deposition in the same areas T when the angle of the streams is relatively open (FIG. 6b).

The roll-to-roll continuous casting machine 1 according to the invention may comprise at least one detector for determining the amount of coating agent present on the surface of the rollers 10, which generates a signal capable of being used in feedback for adjusting the coating composition. Said detector is typically selected from optical detectors, laser systems, cameras, infrared detectors, vibration detectors and mechanical voltage detectors.

In the control method according to the invention, said adjustment can be performed depending on the operating conditions of said machine. It can also be performed in feedback depending on the measurements performed on said casting machine, for example by means of a control loop. Said measurements may include measurements selected from optical measurement, laser measurement, infrared measurement, vibration measurement and mechanical stress measurement. Said adjustment of the composition may be as follows: 4.

-15 · »··» · automated.

The invention relates mainly to the production of base metals, in particular aluminum or copper alloys or copper alloys.

By way of example, aluminum alloy strips 1100 according to the Aluminum Association nomenclature, 3 mm thick and 1800 mm wide, cast in accordance with the invention at speeds of 3.5 mm / min at clamping forces of 1000 t per side, using a 21% mother a graphite slurry diluted with water, adjusting the graphite ratio from 2% to 3%. The surface quality of the strips was verified by macrographical attack of the samples in full width. The Applicant noted a significant improvement in the surface quality of the strips, a better reproducibility of this quality, and a productivity of approximately 10% better than that observed for casting with batch coating, large capacity tanks and simple adjustment of the coating coating flow rate. It attributes these improvements to a more uniform and better controlled distribution of the coating agent.

Non-ferrous or copper belts of the invention, which can be incorporated into existing processes and devices for continuous casting between rolls, allow to improve the quality of the obtained belts and the consistency of the coating applied to the rolls. In particular, the quality is improved by controlling the currents, which can remain the same regardless of the area of operation of the machine. For a given mode of operation, the consistency of the applied coating allows to substantially reduce the amount of coating material required to obtain belts of the specified quality.

Claims (38)

PATENT CLAIMS A method of coating on rolls (ΙΑ, IB) of a roll-to-roll continuous casting machine (1), comprising applying to said rolls at least one coating composition comprising a coating agent and a carrier fluid, comprising adjusting the coating composition Coating agents during roll application. 2. The coating method of claim 1 wherein the composition adjustment comprises adjusting the proportion of coating agent contained in the coating coating material. 3. The method of claim 1 or 2, further comprising adjusting the discharge amount of the coating composition. The coating process of any one of claims 1 to 3, wherein the coating coating is a suspension, a solution or a mixture of both. The coating process according to any one of claims 1 to 4, wherein the coating agent comprises graphite. 6. A method according to any one of claims 1 to 5 wherein the carrier fluid comprises water. The coating process of any one of claims 1 to 6, wherein adjusting the composition comprises diluting the coating agent concentrate in the carrier fluid. • ·· · -178. The method of claim 7, wherein the concentrate is a mother liquor, a concentrated solution, or a mixture of both. The coating process according to claim 7 or 8, characterized in that the concentrate is selected from concentrated suspensions of graphite, boron nitride, colloidal silica, magnesium oxide, organic substances or mixtures thereof. The coating process according to claim 7 or 8, wherein the concentrate is a graphite gel containing from 20 to 30% by weight of graphite. The coating process according to any one of claims 1 to 10, characterized in that said adjustment of the composition is carried out in feedback, depending on the measurements performed on the casting machine. 12. The method of claim 11 including a control loop. The coating method of claim 11 or 12, wherein said measurements include measurements selected from optical measurements, laser measurements, infrared measurements, vibration measurements, or mechanical stress measurements. The coating method according to any one of claims 1 to 13, characterized in that the adjustment of the composition is carried out automatically. 15. Method of continuous casting of metal strips between rolls • Or comprising a method of applying a coating according to any one of claims 1 to 14. 16. A continuous casting method according to claim 15, wherein said metal strips are of aluminum, of an aluminum alloy, of copper or of a copper alloy. Apparatus for coating rollers (ΙΑ, 1B) of a roll-to-roll continuous casting machine (1), comprising means (5, 51, 52, 6, 61, 62, 7, 8, 20, 21) for applying at least one a coating composition (24) on said rollers, characterized in that it comprises means (30 to 41) for adjusting the composition of said coating composition during application to said rollers. The coating device of claim 17, wherein said composition adjusting means comprises a mixer (40), a coating agent supply (41), a coating agent supply control means (32), and a carrier fluid supply (30). The coating device of claim 18, wherein the control means (32) comprises a metering pump. The coating device of claim 18 or 19, wherein the coating agent supply (41) comprises a tank (34) capable of containing the coating agent concentrate (35). 21. A coating device according to any of the above Claims 17 to 20, characterized in that it comprises means (38, 39) for homogenizing the coating coating material. A coating device according to any one of claims 17 to 21, characterized in that the coating means comprise means for controlling the flow rate of the spraying means (5, 51, 52). Painting device according to any one of claims 17 to 22, characterized in that the coating means comprise a spraying means (5) for each roller (ΙΑ, 1B) and means (80 to 84) for moving said spraying means (5). along each cylinder. Coating device according to any one of claims 17 to 22, characterized in that the spraying means comprise at least two spraying means (51, 52) for each roller (ΙΑ, 1B), the spraying means forming a connected whole, and further comprising means (80-84) for moving each said assembly along each cylinder. 25. The coating device of claim 24 wherein the spray means of each of said units is superimposed. Coating device according to any one of claims 23 to 25, characterized in that said transfer means (80 to 84) allow to move said spray means by reciprocating along an axis parallel to the roll axis (A, B). • · · · · · · · · · · · · · · · · · · · -2027. Coating device according to any one of claims 17 to 22, characterized in that said spraying means comprise at least two spraying means (5) per roller, said spraying means being disposed on a line substantially parallel to the axis (A, B). each of said rollers (ΙΑ, 1B). 28. The coating device of any of claims 17 to 22, comprising means for oscillating at least one of said spray means relative to said axis. Coating device according to any one of claims 17 to 28, characterized in that the spray means (5, 51, 52) are selected from the group comprising nozzles and guns. A coating device according to any one of claims 17 to 29, characterized in that it comprises means for feedback control of said composition adjustment depending on the measurements performed on said casting machine. A coating device according to any one of claims 17 to 30, characterized in that it comprises means for automatically controlling said composition adjustment. Paint application device according to any one of claims 17 to 31, characterized in that said means (30 to 41) for adjusting the composition of the coating material can be a separate adjustment device (42), removable and / or demountable. • · ··································· -2133. A machine for continuously casting metal strips between rolls, provided with a coating device according to any one of claims 17 to 32. Machine according to claim 33, characterized in that it comprises at least one detector for determining the amount of coating agent present on the roller surface (10), which generates a signal capable of being used for feedback adjustment of the coating composition composition. 35. The machine of claim 34 wherein said detector is selected from optical detectors, laser systems, cameras, infrared detectors, vibration detectors, and mechanical voltage detectors. A method of controlling a machine (1) for continuously casting metal strips between rolls by applying at least one coating composition comprising a coating agent and a carrier fluid to said rolls, comprising adjusting the composition of said coating composition during application to said coating composition. war. Control method according to claim 36, characterized in that said adjustment is performed in dependence on the operating conditions of the machine (1). 38. The control method according to claim 36 or 37, wherein said adjustment is performed in feedback, depending on the measurements made on the casting machine. Control method according to claim 38, characterized in that 4 4 4 4 4 ···· »44 44 44 44 44 44 -22 that it contains a control loop. The control method of claim 38 or 39, wherein said measurements include measurements selected from optical measurement, laser measurement, infrared measurement, vibration measurement or mechanical voltage measurement. A control method according to any one of claims 36 to 40, characterized in that said adjustment of the composition is carried out automatically.