DE69922479T2 - Improved continuous casting mold - Google Patents

Abstract

An improved mold and process for continuous casting involves the use of a mold surface that is fabricated from a material, such as diamond, that is nonmetallic, an efficient conductor of heat and that is more degradation-resistant than the conventional materials and coatings that are used on mold surfaces. In one embodiment, the nonmetallic material is bonded to a conventional mold liner. In a second embodiment, the entire mold wall can be fabricated from the nonmetallic material. In another aspect of the invention, since materials such as diamond are transparent in the infrared range, the temperature of the outer shell of the casting can be monitored through the nonmetallic material without interfering with the casting process, and this information can be used to control one or more variables in the casting process.

Description

BACKGROUND OF THE INVENTION

1. Field of the invention

The The present invention relates to metal production and processing after the continuous casting process. In particular, it relates to an improved Kokillenfläche for one Continuous casting plant and a system and method for controlling the casting process by monitoring the actual temperature of the cast strand on the mold surface at working plant.

2. Description of the state technology and related technology

since the large-scale introduction About 30 years ago, metals are increasingly being used in the continuous casting process currently produces a significant share of steel volume - under other metals - that makes up, which is produced worldwide. As is known, have continuous casting plants typically a mold with two substantially parallel ones and opposite lying wide and two substantially parallel and opposite narrow walls on, the latter with the wide walls to form a sprue interact with a rectangular cross-section. Melt is continuous filled in an upper end of the casting channel; the mold is constructed, to cool the metal, leaving an outer skin or shell forms before the strand thus formed at the bottom the casting channel exits.

Around the heat emanating from the molten steel to dissipate efficiently, are the shaping mold surfaces typically with copper or a surface layer of copper alloy lined, the numerous channels contains through which water flows when molding, for a rapid heat exchange to ensure. In some cases the mold is cooled, by placing water directly on the colder side of the mold lining sprayed. The strand is additionally cooled when leaving the mold by spraying until it completely has solidified. He let then according to conventional Procedure - eg. Rolls - too a metal intermediate or finished product, such as steel plates, continue to process sheet metal or coils.

The shaping inner surfaces the mold - too known as their "hot surfaces" - are for longer periods of time the high temperatures of molten steel and corrosive flux exposed. Although copper is a very good conductor of heat, it is relatively soft; therefore, it wears it's easy and its qualities also worsen on others Species. Under normal working conditions, the hot surfaces of the mold wear out relatively quickly; they wear off, tear and are removed by water vapor and chemical action. This effect is exacerbated by high speed kokillen that tends to be higher Temperatures work and where the copper material is even softer. Applicant, AG Industries, Inc., is the largest provider of maintenance and repair services for Continuous casting plants in the US market and therefore with the degradation and wear of Kokilleninnenflächen to water very familiar.

To extend the useful life of mold inner surfaces as much as possible, typically the copper mold inner surface is coated with a material resistant to friction and corrosion such as nickel or chromium. Other techniques for protecting the inner mold surfaces have been proposed and / or used commercially. For example. reveals that U.S. Patent No. 5,499,672 a method for protecting a copper mold surface by applying a protective metal carbide material. According to another protective coating method, a Ni-Cr alloy is hot-sprayed onto the copper mold surfaces. This process is described in the document "Ni-Cr Alloy Thermal Spraying of the Narrow Face of Continuous Casting Mold", May 1989, Nippon Steel Corporation and Mishima Kosan Co., Ltd. While the coatings developed so far have been able to reduce the speed and extent of mold wear to some extent, it is part of the continuous casting industry that the mold surfaces must be periodically removed and replaced or repaired. The removal of a mold from the casting line represents a significant cost factor for the steelmaker, perhaps up to $ 15,000 per hour.

The strand or slab has a very thin skin upon initial formation in the mold. A crack of the shell must be prevented by all means, otherwise it comes to the known as "breakthrough" state in which melt escapes through the shell to the mold. In the case of heavy breakthroughs, parts of the system that are in their path can be encased in melt; they then become unusable and must be replaced or worked up. One of the factors responsible for that Detecting a possibly imminent breakthrough is important, the thickness of the shell during the passage of the casting by the mold. Theoretically one could measure the shell thickness when casting in situ by measuring the infrared radiation of the slab; This has proved to be practically impossible, since the mold completely surrounds the slab and a measurement is impossible. In some systems, an attempt is made to model the casting thickness by sensing the temperature at selected locations in the mold liner; however, these systems may be worse than accurate due to the varying thickness of the copper layer between the sensors and the strand surface.

The JP 62 130748 discloses a water-cooled mold with a ceramic lining intended to improve wear resistance and durability. The form lining is composed of boron nitride with a thermal conductivity of at least 50 W / mK. However, this form does not relate to continuous casting. WO 98/16335 shows an aluminum mold with mold wall arrangements with an inner part which is intended to dissipate heat from the mold lining and a boron nitride or diamond coated inner part.

It There is a need for a continuous casting mold, with which the cast strand when passing through it is better monitored, so that breakthroughs and other undesirable ones conditions prevent it.

SUMMARY OF THE INVENTION

It is an object of the present invention, a continuous casting mold indicate that improves monitoring allows the cast strand while passing through it, so that breakthroughs and other undesirable ones conditions prevent it.

Around to achieve this and other objects of the invention, a or mold wall arrangement for use in a continuous casting machine according to claim 1 below. In claim 7 is a continuous casting machine with a preferred embodiment specified. According to another aspect of the invention provides this a method for producing a strand of continuously cast Material according to claim 8 below ready.

To the better understanding the invention, their advantages and achieved by their use Goals should be to the drawings, which is another part of the application as well as the attached Description directed, which describes a preferred embodiment of the invention and explained.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a horizontal partial section through a mold wall assembly for a continuous casting machine according to a preferred embodiment of the invention;

2 is a vertical section through a part of the in the 1 shown arrangement;

3 shows diagrammatically a preferred feature in the arrangement 1 and 2 ;

4 shows diagrammatically a preferred rule for in the 1 to 3 arrangement shown;

5 is a vertical partial section through a mold wall assembly according to a second embodiment of the invention; and

6 is a vertical partial section through a mold wall assembly according to a third embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED MODE (S)

In the various figures of the drawing, like reference numerals designate like structural parts. The 1 shows an improved mold or mold wall arrangement 12 for a continuous casting machine 10 ; it has a plurality of mold walls including a pair of opposing narrow walls 14 . 16 and a pair of opposite wide walls 18 . 20 on. The mold walls 14 . 16 . 18 . 20 each have at least one inner surface, which together form a casting space 26 enclose with an upper and a lower opening. As usual, the mold wall assembly 12 designed so that melt continuously into the upper end of the casting space 26 feed and form an outer skin or shell before the slab or strand thus formed emerges at the lower end of the casting channel. As is also common, are coolant feed tubes 22 . 24 provided, with which the narrow and the broad walls 14 . 16 respectively. 18 . 20 Cooling water can be supplied.

The 2 shows a vertical section through a ( 20 ) of the wide walls of the 1 , As can be seen, the wall points 20 a lining 27 that the molding surface 28 carries, and a support assembly 32 on, at the lining 27 is fixed. As in 2 seen, has the lining 27 an inner part 29 acting as copper lining layer 30 is executed, as well as an outer layer 44 from a non-degradable non-metallic material, which forms the surface 28 forms and is discussed in more detail below. The support arrangement 32 has a coolant inlet 24 , a coolant drain 42 , an inlet manifold 36 and a drain distributor 38 on. The inlet and outlet manifolds 36 . 38 are in flow communication with a cooling channel 34 that in the copper lining layer 30 the lining 27 is trained. In operation, as usual, the coolant - typically water - from the coolant inlet 24 into the feed distributor 36 fed from where it up through the cooling channel 34 and into the drain distributor 38 flows. Thereafter, the coolant returns through the drain 42 back to a circulation pump.

The layer 44 Non-metallic material resistant to degradation consists of diamond or cubic boron nitride. These fabrics are effective heat conductors, very hard and resistant to degradation; they tolerate the high temperatures encountered in a continuous casting mold during operation, resist the acidic environment in which a continuous casting machine typically operates, and are transparent in the infrared region of the spectrum, for reasons discussed in more detail below.

diamond is a carbon allotrope which is metastable at ordinary pressures and whose high activation energy acts as a barrier that allows for conversion Graphite, the usual Temperatures and pressures more stable allo trop, prevented. He is not only because of his beauty and desires its value as a gemstone, but also because of it many unique and valuable mechanical, electrical, optical and thermal properties. Diamond is the hardest naturally occurring Material, has a low coefficient of friction, is extremely resistant to chemical attack, in a large part of the electromagnetic Spectrum - incl. of the IR area - transparent and has the highest thermal conductivity all substances. The properties of cubic boron nitride (CBN) are in many ways comparable to those of diamond.

The 3 shows diagrammatically an advantageous feature of the invention. Like from the 2 and 3 it is apparent in the copper layer 30 the lining 27 a channel 46 educated. In the channel 46 is an optical fiber 48 used and with the casting or molding surface 28 opposite side of the transparent layer 44 optically coupled against degradation resistant non-metallic material. With a second opposite end of the optical fiber 48 is then a sensor 50 coupled. The purpose of the sensor 50 is to monitor a property of the continuous casting process by monitoring the spectral characteristics of the light that makes up the optical fiber 48 passes. In its preferred embodiment, the sensor 50 is constructed and arranged to detect and monitor the infra-red profile of the transmitted light and thus the temperature on the outer surface of the casting which travels down the casting surface in the mold. By monitoring this temperature, the thickness of the casting shell can be determined, which is a useful indicator of various things - for example, the breakdown tendency of the strand after leaving the lower Kokillenendes, the optimal exit speed of the strand from the machine, the optimal coolant flow in the Kokillenwandungen and the uniformity of the increase in shell thickness. As the 4 shows is a number of such sensors 50 provided in the mold assembly, each providing information to a CPU 52 deliver that as a local scheme for the mold assembly 12 serves. The CPU 52 is in duplex transmission connection with a main control 54 the continuous casting machine 10 and with various subsystems to readjust various operating variables of the continuous casting process. The 4 shows four such subsystems 56 . 58 . 60 . 62 ; their number may be larger or smaller, depending on the number of operating variables to be monitored, by means of the optical monitoring by the sensor 50 to be controlled. For example. For example, one of the subsystems may allow readjustment of the withdrawal speed of the continuous casting plant, and another of the shape of the casting. A third and a fourth subsystem for controlling the cooling can detect the coolant throughput in one or more mold walls or the composition of the flux and thus the thermal conductivities of the mold.

For analysis of the sensors 50 recorded data can be a commercial heat imaging system. A suitable such system is available from the company Micro Instruments, Oakland, New Jersey [USA] and is sold as an "imaging pyrometer". The system is partially in the U.S. Patent 4,687,344 the teaching of which is to be incorporated by reference as part of the present application.

The 5 shows a mold assembly 64 according to a second embodiment of the invention with a casting surface 66 and a main part 68 made entirely of the non-metallic, anti-degradation material of the kind detailed above. In the main part 68 is a cooling channel 70 formed out of and a sensor 72 In construction, the above discussed sensor 50 corresponds to, is with a back of the main part 68 coupled. In this embodiment of the invention, the entire mold wall is made of diamond or CBN. This embodiment appears to offer the greatest potential for the future, as it is expected to significantly exceed the performance of any currently used mold wall. Completely made of a material like diamond, it would dissipate heat from the strand much more efficiently during casting than a metal mold wall; it would show less friction than any metal mold wall and would be virtually indestructible in terms of wear.

The 6 shows still another embodiment of the invention. In this embodiment - as in the above with reference to 5 described - is the entire mold lining 80 made of a non-degradation resistant high thermal conductivity non-metallic material so that when used in a continuous casting plant, the lining exhibits superior wear and heat conduction properties. As in the embodiment according to 5 the preferred material is diamond or CBN; the lining can be made by any of the methods discussed below or any other effective method. A sensor 72 in construction the sensor discussed above 50 corresponding sensor 72 is with a back of the mold lining 80 coupled. In this embodiment, the liner includes 80 no internal cooling channel, but is injection-cooled, with the cast strand 82 opposite side 86 the lining of one or more spray nozzles is sprayed with coolant. The high thermal conductivity of such a Kokillenauskleidung contributes to an effective cooling of the cast strand and the formation of a uniform solidified shell 84 at the same time. In addition, as a result of the transparency of the mold in the infrared range, a significant amount of heat is dissipated by radiation away from the cast strand - this in favorable contrast to a conventional continuous casting mold, in which no heat dissipation by radiation through the mold wall takes place.

It There are a number of known methods for building coatings and masses of materials such as diamond and CBN; recognize the inventors that any of these methods are within the scope of the invention can be used. The inventors further recognize that this technology developing very rapidly, and assume that to provide the required structure other, more efficient techniques - as soon as available - usable become. The following US patents and PCT publications reveal methods for artificial Build up coatings and masses of materials like diamond and CBN and are meant for the purposes of the disclosure are considered exemplary. The listed publications are intended to be incorporated by reference as part of the present application be valid:

MOST PREFERRED METHOD TO APPLY THE ABBAUBSTÄNDIGEN NON-METAL LAYER

According to one embodiment, the method of the U.S. Patent 4,490,229 used, can be in the surface of a substrate to introduce a diamond-like thin carbon layer by exposing the surface of a hydrocarbon-containing argon ion beam. During the initial deposition of the thin film, the current density in the ion beam is low. Following this initial low current, the ion current is ramped up to full power. At the same time, a second argon ion beam is directed onto the substrate surface. The energy level of the second ion beam is much higher than that of the hydrocarbon ion beam. This energy input to the system enhances the mobility of the condensing atoms and serves to remove weaker bound atoms and increase the proportion of diamond bonds.

In a second embodiment, with the method according to the U.S. Patent 4,504,519 For example, an amorphous C-containing diamond-like thin film is hybrid-deposited in a treatment chamber with RF plasma decomposition of an alkane such as n-butane by means of a pair of spaced, generally parallel carbon electrodes, preferably of ultra-pure carbon. While most thin films according to the invention were applied from normal butane, according to the invention it is also possible to use other alkanes, such as methane, ethane, propane, pentane and hexane, to prepare the improved C-containing diamond to produce a thin film. The deposition chamber, for example of stainless steel, has a pair of generally parallel horizontal, vertically spaced, pure carbon electrodes; The substrate to be coated is placed on the lower C electrode. The electrodes are typically spaced about 20 to about 80 mm, preferably about 25 mm apart. The chamber is evacuated to its final pressure, generally in the range of about 10 ^-7 torr, and then backfilled with an alkane such as n-butane to about ^{8x10 -4} torr. Thereafter, the vacuum system is throttled to a pressure in the range of about 25 to 100 mTorr. After the pressure is stabilized, the RF power is applied to the two bare-C electrodes, and the lower electrode (substrate target) is in the range of about 0 V to about -100 V and the upper electrode in the range of about -200 V to biased about -3500V. RF plasma decomposition is initiated and an amorphous C-containing diamond-like thin film is deposited on the substrate at a rate of between about 8 Å / min to 35 Å / min to about 5 μm thickness.

In a third embodiment, with the method of U.S. Patent 4,770,940 is working, a hard C-containing thin film is formed by decomposing a hydrocarbon in gaseous form whose carbon atoms are tetrahedrally coordinated with the nearest neighbors via CC single bonds. The gaseous hydrocarbon is decomposed in a plasma maintained in the RF field and the plasma decomposition products are deposited on a cathodic substrate. Optionally, hydrofluorocarbons ("fluorocarbons") may also be present in a decomposition gas.

In a fourth embodiment, with the method of U.S. Patent 4,830,702 operates, a hydrocarbon / hydrogen gas mixture is passed through a refractory metal hollow cathode, which is heated to a high temperature. The gas mixture decomposes by a combination of thermal and plasma effects. The plasma cloud emerging from the hollow cathode heats the substrate, which is placed on a surface of the anode. The thickness increase of the diamond thin film is improved by electron bombardment.

In a fifth embodiment, using the method of U.S. Patent 4,910,041 operates, a thin film is formed on a substrate substrate by contacting the substrate with a plasma zone which is formed by forming with one or more discharge electrodes a high-temperature or quasi-high-temperature plasma of a gas containing at least one C-containing compound. One of the electrodes may be a flat electrode connected to a microwave source with a slit having a straight section. Alternatively, the plasma zone is formed by causing a high-temperature or quasi-high-temperature plasma generated in an arc between the electrodes to move by applying a magnetic field. This process allows thin films to be deposited on substrates in an energy-efficient manner.

In a sixth embodiment, with the method according to U.S. Patent 4,939,763 a synthetic diamond layer can be formed by deposition supported by a direct current plasma, the plasma current being 0.5 A to 1 A and the temperature of 600 ° C. to 800 ° C., and methane / hydrogen (volume ratio 0.8-1 to 99.5-1) at a total pressure of 20 Torr to 30 Torr.

In a seventh embodiment, the method of the U.S. Patent 4,948,629 applies diamond layers on substrates at temperatures below 400 ° C by chemical vapor deposition using a high-power impulse laser and a vapor, which is an aliphatic carboxylic acid or an aromatic carboxylic anhydride.

In an eighth embodiment, the method of the U.S. Patent 4,954,365 For example, a diamond thin film is formed by dipping a substrate in a liquid containing carbon and hydrogen and then subjecting it to at least one laser pulse.

In a ninth embodiment, using the method of U.S. Patent 4,981,717 For example, one method of depositing diamond-like films results in the deposition of species from a plasma of a hydrocarbon gas precursor. The plasma is generated by a laser pulse, which is fired into the gas and absorbed in an initiator mixed with the gas. The resulting detonation generates a plasma of ions, radicals, molecular fragments, and electrons that is propelled and deposited by the blast wave of the detonation onto a substrate.

In a tenth embodiment, with the teaching of U.S. Patent 4,987,007 is working, a method and apparatus are used which form a layer of material on a substrate by extracting ions from a laser ablation cloud in a vacuum. In a basic embodiment, the Device on a vacuum chamber containing a target material; Focusing on the target, a laser ablates the material and ionizes a portion of the ablation cloud. An acceleration grid in the vacuum chamber is charged so that the ions are extracted from the cloud and directed to a substrate to grow the layer. The base embodiment yielded diamond-like carbon layers on a non-seeded clean silicon substrate at a deposition rate of nearly 20 μm / hr. The diamond-like C films thus produced had excellent quality: constant thickness with a surface roughness of about 1 Å, a uniform refractive index in the range of 1.5-2.5, a resistivity greater than 40 MΩ / cm, and an against mechanical stress Resistant hard surface. In an improved embodiment, multiple targets and mechanisms are arranged in the vacuum chamber to generate ions from each target. Thus, layers of different or doped substances can be formed on the substrate. Furthermore, in this embodiment, a mechanism is provided to form patterns or circuits in each layer. In one version, a mask in the ion fluence and ion optics are provided to increase the mask pattern on the substrate. Another version uses an ion optics to form an ion beam and these controlling baffles, by means of which the target pattern on the substrate can be written.

An eleventh embodiment using the method of U.S. Patent No. 5,015,528 employs a method of producing synthetic diamond in which a source of carbon gas is evaporated in the presence of atomic hydrogen onto a substrate in a fluidized bed. The diamond layer can in turn be coated by vapor deposition of a non-diamond substance.

A twelfth embodiment uses the method of U.S. Patent No. 5,071,677 at. In this process, diamond thin films and particles are formed on various substrates by flowing a gas or gas mixture capable of supplying (1) carbon, (2) hydrogen and (3) a halogen in a reactor over the substrate material. The reaction gases can be premixed with an inert gas in order to set a small volume fraction of carbon and a high volume fraction of hydrogen in the total gas mixture. In contrast to most known methods of chemical vapor deposition of diamond, a pretreatment of the reaction gases to a high energy state is not required. Since no pretreatment is necessary, application to substrates of virtually any desired size, shape or configuration is possible. The reaction gas mixture is preferably passed through a reactor the first portion of which is heated to a temperature of from about 400 ° C to about 920 ° C, preferably from about 800 ° C to about 920 ° C. The substrate on which the diamond layer is to grow is placed in a zone of the reactor which is maintained at a lower temperature of from about 250 ° C to about 750 ° C, ie, the temperature range preferred for diamond growth. The treatment is preferably carried out at ambient pressures; higher or lower pressures are possible. Reindiamant layers and particles were obtained in significant quantities with treatment times as short as eight hours. The purity of diamond films and particles was verified by Raman spectroscopy and powder X-ray diffraction techniques.

A thirteenth embodiment of the invention operates with the method of U.S. Patent No. 5,080,753 , In this case, epitaxially oriented cubic boron nitride single crystal thin films are formed on a silicon substrate using laser ablation techniques.

A fourteenth embodiment of the invention operates with the method of U.S. Patent 5,082,359 , For the formation of a polycrystalline thin layer, for example, from diamond on a foreign substrate, this is pretreated prior to the application of the layer in order to apply discrete germination sites. The substrate is pretreated for coating by forming a pattern of irregularities in its surface. The irregularities - typically craters - are arranged in a predetermined pattern that corresponds to the desired pattern of the layer crystals. The craters preferably have constant predetermined dimensions (in the submicron and micrometer range) and distances. They can be formed using a variety of techniques including ion beam milling, laser evaporation, and chemical or plasma etching with a patterned photoresist. After preparing the substrate, the thin film is applied by any one of a number of known methods. Thin films produced in this way are characterized by a regular surface pattern of crystals which can be arranged in practically any desired shape.

In a fifteenth embodiment, the method of the U.S. Patent 5,096,740 is applied, a high purity CBN layer is formed on a substrate by using an excimer laser, a target of boron and optionally also nitrogen atoms irradiated and the CBN is applied to a substrate arranged facing the target.

A sixteenth embodiment of the invention operates with the method of U.S. Patent 5,154,945 , There With infrared lasers diamond thin films are applied to a substrate. In one embodiment, the application of the thin film is carried out from a gas mixture of CH ₄ and H _2, which is fed into a deposition chamber and allowed to flow over the substrate to be coated, while irradiating the surface thereof with the laser. In another embodiment, pure carbon in the form of carbon black is placed on the surface to be coated and the laser beam is directed onto it in an atmosphere that prevents the carbon from burning to CO ₂ .

A seventeenth embodiment operates with the method of U.S. Patent 5,221,411 , Here, in a process for developing diamond thin films on a non-diamond substrate, carbon ions are implanted into a substrate of matching lattice plane or lattice. The implantation region is then annealed to produce a diamond thin film on a non-diamond substrate. The diamond thin films produced by this process are also disclosed on non-lattice-matched substrates. Preferred substrates are diamond-lattice matched to diamond, such as copper, a preferred implantation method is ion implantation, and a preferred annealing method is pulsed laser annealing.

In an eighteenth embodiment, using the method of U.S. Patent 5,221,501 is working, a method of producing transparent diamond laminates is used, wherein one works with a substrate, which is removed after the application of a second layer on the diamond layer, so that a smooth diamond surface is exposed. The second coating should have a refractive index substantially equal to that of diamond; Zinc selenide and titanium dioxide are particularly preferred. Two smooth surface diamond layers can be formed by simultaneously coating parallel opposed substrates until the two diamond layers merge into a single thin film, followed by removal of at least a portion of the two substrates.

In a nineteenth embodiment, the method of the U.S. Patent 5,230,931 For example, a diamond thin film or "I carbon layer" is formed on a surface of an article by plasma enhanced chemical vapor deposition. The hardness of the layers can be improved by applying a bias to the article during coating.

In a twentieth embodiment, the method of the U.S. Patent 5,236,740 is used, a cemented tungsten carbide substrate is prepared for depositing a diamond thin film by subjecting the substrate surface to be coated to a process of first removing a small amount of the tungsten carbide on the substrate surface while leaving the cobalt binder substantially intact. Currently, Murakami solution is preferred. Then, the substrate is subjected to a treatment with which material remaining from the tungsten carbide removal on the surface is removed. At present, a solution of sulfuric acid and hydrogen peroxide is preferred. A diamond-coated cemented tungsten carbide tool is formed using an unpolished substrate, which is etched by etching. above description or etching in nitric acid before applying the diamond layer. The application of a substantially continuous diamond layer can be achieved by reactive vapor deposition with thermal assisted (hot wire) CVD ("chemical vapor deposition"), plasma assisted CVD, or other methods.

In a twenty-first embodiment, the method of the U.S. Patent 5,243,170 For example, if a diamond thin film is applied to a substrate by a plasma jet coating method in which the deposited diamond thin film has a predominantly hexagonal crystal structure unlike the cubic crystal structure formed under conventional conditions, the advantages of diamond coating the tool be further emphasized in terms of hardness and smoothness of the coated surface. The improvement consists of using only hydrogen as the plasma generating gas, a plasma atmosphere pressure of not more than 300 Torr, a substrate temperature of only 800 ° C to 1200 ° C, and a temperature gradient of at least 13000 ° C / cm within the boundary layer on the substrate surface ,

In a twenty-second embodiment, the with the method of the US-PS 5 260 106 works, a diamond layer is stuck to the substrate applied by putting a first layer on the surface a mixture of a main component of the substrate and a sintering reinforcement for diamond, then on the first a second layer of a mixture of sintered reinforcement and the diamond and finally on the second layer the diamond thin film formed.

In a thirty-third embodiment, the method of the U.S. Patent 5,264,071 used For example, the bond strength between diamond and the substrate to which it is chemically evaporated is reduced so much that the diamond can be removed from the substrate as a free standing monolithic sheet. The bond strength can be reduced by polishing the substrate, removing substrate corners, slow cooling of the substrate after coating, and an intermediate temperature delay on cooling or by forming an intermediate layer between the diamond and the substrate. The freestanding diamond blade is considered to be particularly suitable for the embodiment according to 5 ,

In a twenty-fourth embodiment, the method of the U.S. Patent 5,271,890 is used, a layer of a carbon allotrope is formed on a substrate by adding finely divided carbon powder to the substrate, irradiating the powder with a high-power laser, thereby initiating sublimation of the finely divided carbon powder and quenching the sublimated fine carbon powder to deposit it on the substrate deposit.

In a twenty-fifth embodiment, the method of the U.S. Patent 5,273,731 applies, a substantially transparent polycrystalline diamond layer is produced with more than 50 microns thick. A hydrogen-methane mixture is introduced into a filament reaction zone adjacent to a suitable substrate, such as a molybdenum substrate, to form a non-adherent polycrystalline, substantially transparent diamond layer.

In a twenty-sixth embodiment, which the method according to US-PS 5 273 788, according to the Langmuir-Blodgett method a Layer of a hydrocarbon molecule applied to a substrate and the surface irradiated with a laser to decompose the molecular layer on the surface, without to influence the substrate. After decomposition, the carbon atoms arrange on the substrate surface to a diamond-like layer ("DLC layer").

In a twenty-seventh embodiment, the method of the U.S. Patent 5,302,231 In a method of growing diamond on a diamond substrate by chemical vapor deposition, the diamond substrate is alternately contacted with a gas of the formula C _n X _m and then with a gas of the formula C_Z _p at elevated temperature. X and Z are each a single bond with carbon. X and Z also react to form ZX or a derivative thereof. The ZX bond is stronger than the CX and stronger than the CZ bond. In the formulas, n, m, _ and p are each an integer.

In a twenty-eighth embodiment, the method of the U.S. Patent 5,516,500 For example, diamond materials are made by placing a carbonaceous material in a gap between two electrodes and flowing a strong electric current between the two electrode plates to rapidly heat the carbonaceous material. The current is sufficient to heat the carbonaceous material at at least 5000 ° C / sec and only needs to be applied for a fraction of a second to raise the temperature of the carbonaceous material to at least about 1000 ° C. When the current is removed, the carbonaceous material is quenched (cooled). For this one can bring one or more of the electrodes into contact with a heat sink, such as a large steel table. The carbonaceous material may be repeatedly heated (eg, in cycles) rapidly and quenched (RHRQ method) until a diamond material is formed from the carbonaceous material. The process is preferably carried out in an environment of "shielding" gas (inert or non-oxidizing gas) such as argon (Ar), helium (He) or nitrogen (N ₂ ). According to one embodiment of the invention, the carbonaceous material is polystyrene (for example a thin layer) or glassy carbon (for example thin layer or powder). In another embodiment of the invention, the carbonaceous Ma material is a polymer, a fullerene, amorphous carbon, graphite or the like. One of the electrodes is preferably a substrate on which a diamond coating is to be formed, wherein the substrate itself as one of serves both electrodes.

In a twenty-ninth embodiment, the method of the U.S. Patent 5,525,815 is disclosed, a continuous diamond structure produced by chemical vapor deposition, which has at least two diamond layers of different thermal conductivity, which have been set with the growth rate of the diamond, wherein the diamond layer of a high thermal conductivity of at least 1 micron / h at filament CVD and at least 2 μm / h in microwave plasma assisted CVD on a substrate such as molybdenum in a CVD chamber and at the high growth rate promoting substrate temperature; the diamond layer of the other thermal conductivity is applied at a lower growth rate and substrate temperature than the high thermal conductivity layer. The high and low growth rate diamond layers can be applied in any order to achieve a continuous diamond structure that does not exhibit distinguishable separate crystalline column layers and improved thermal conductivity.

In a thirtieth embodiment using the method of PCT Publication WO 95/31584 (corresponding to International Application PCT / US95 / 05941), the energy becomes, for example, a UV excimer, infrared Nd: YAG and infrared CO ₂ laser is directed through a nozzle onto the surface of a substrate to mobilize and vaporize a carbon component (eg carbide) in the substrate (eg steel). The nozzle also dispenses an additional secondary source (eg, a carbonaceous gas such as CO ₂ ) and an inert shielding gas (eg, N ₂ ). Under the applied energy, the vaporized element changes its physical structure (e.g., from carbon to diamond) to that of a composite material, which as such diffuses back to the backside of the substrate.

In a thirty-first embodiment using the method of PCT Publication WO 95/20253 (corresponding to International Publication No. PCT / US95 / 00782), laser energy is directed to a substrate to form a constituent (primary) element (e.g. To mobilize, vaporize, and react in the substrate to alter the composition (eg, the crystal structure) of the constituent element and modify the element to diffuse back into the substrate as an additive to produce a coating (eg, diamond or diamond-like) Carbon) on the substrate surface. In this case, immediately below the substrate, a conversion zone is formed, which metallurgically transitions from the composition of the underlying substrate to that of the coating produced on the substrate surface; The result is a diffusion bonding of the coating to the substrate. Additional (secondary) like (eg, carbon) or dissimilar elements may be added in a reaction zone on and above the substrate surface to aid in the formation of the coating and to determine its composition. The laser energy is provided by a combination of excimer and Nd: YAG and CO ₂ lasers whose jets are preferably directed through a nozzle which also directs the secondary element to the reaction zone. The reaction zone is screened with an inert inert shield gas (e.g., N ₂ ) which is fed through the nozzle. The laser, constituent and secondary elements create on the substrate surface a plasma layer that optionally extends around the substrate edges to form a coating on the substrate. Pretreatment and deposit generation can be done together (in situ). Alternatively, a substrate pretreates to characterize its surface for subsequent coating. In both cases, the substrate undergoes certain advantageous metallurgical changes as a result of the pretreatment. The treatments (pretreatment and coating) are expediently carried out in an environment without preheating the substrate and without vacuum. The lasers are applied at any suitable angle (also coaxial) relative to the substrate and / or plasma.

It It should be noted that, although in the foregoing description numerous features and advantages of the present invention - together with details of their structure and operation - set out are, this revelation has to be considered exemplary only and itself within the principles of the invention in detail - in particular in terms of shape, size and arrangement of parts - changes carry out which are fully within the scope of the general meaning of the expressions, with those attached claims expressed are.

Claims (15)

Mold wall arrangement ( 20 ) for a continuous casting machine comprising: an inner part ( 29 ) which is constructed and arranged such that, in use, it transfers heat from a mold lining ( 30 ) and an outer surface ( 44 ), which has a casting surface ( 28 ) of the mold and made of a material selected from the group consisting of diamond and cubic boron nitride; characterized in that the mold wall arrangement ( 20 ), optical monitoring equipment ( 48 . 50 ) for optically monitoring a property of the continuous casting process by the material ( 44 ) and an optical waveguide ( 48 ), which is in contact with the material ( 44 ) on one side thereof, the casting surface ( 28 ) lies opposite the mold, is optically coupled. Mold wall arrangement ( 20 ) according to claim 1, in which the optical monitoring device ( 48 . 50 Spectral measuring devices for measuring the spectral properties of the material ( 44 ) and means for analyzing the spectral characteristics of light measured by the spectral measuring device. Mold wall arrangement ( 20 ) according to claim 2, the optical monitoring device ( 48 . 50 ) further comprises means for modifying at least one execution variable of the continuous casting process in response to the analysis performed by the means for analyzing the spectral characteristics of light measured by the spectral measuring device. Mold wall arrangement ( 20 ) according to claim 2, wherein the device for analyzing the spectral properties of light measured by the spectral measuring device comprises means by which the temperature of an outer surface of the cast strand is detected, which is arranged adjacent to the mold wall assembly. Mold wall arrangement ( 20 ) according to claim 3, wherein the means for modifying at least one execution variable of the continuous casting process in response to the analysis carried out by the means for analyzing the spectral characteristics of light measured by the spectral measuring means comprise means for adjusting the drawing speed of a continuous casting machine. Mold wall arrangement ( 20 ) according to claim 3, wherein the means for modifying at least one embodiment variable of the continuous casting process in response to the analysis performed by the means for analyzing the spectral property of light measured by the spectral measuring means comprises means for adjusting the speed with which heat is dissipated from the inner part becomes. Continuous casting machine ( 10 ) with a mold wall arrangement ( 20 ) according to claim 1, which machine has a plurality of sensors ( 50 ) which visually monitors said characteristic of the continuous casting process and sends information to a CPU ( 52 ) in two-way communication with a main controller ( 54 ) of the continuous casting machine ( 10 ), wherein one or more subsystems each control an execution variable of the continuous casting process in response to data collected by the sensors, and the execution variables are selected from the group consisting of: (a) adjusting the withdrawal speed of the continuous casting machine; (b) adjusting the draft; (c) adjusting the cooling rate by adjusting the volume flow of a coolant through one or more of the mold walls; and (d) adjusting the cooling rate by changing the composition of the flux and thereby changing the thermal conductivity of the mold. A method of making a strand of continuously cast material by: (a) introducing molten metal into a mold having a plurality of molding surfaces ( 27 ), of which at least one is an outer surface ( 44 ) of a material selected from the group consisting of diamond and cubic boron nitride; (b) cooling the melt by removing heat therefrom through the outer surface; and (c) removing the casting from the mold; characterized in that a property of the continuous casting process by the outer surface material ( 44 ) using an optical waveguide ( 48 ), which is in contact with the material ( 44 ) on the casting surface of the mold ( 27 ) opposite side thereof optically coupled. Method according to Claim 8, in which the optical surface of a material of the continuous casting process is visually monitored by the outer surface material ( 44 ) measures the spectral properties of light transmitted through the material and analyzes the spectral characteristics of light measured by the spectral measuring device. The method of claim 9, further comprising at least one execution variable of the continuous casting process in response to the spectral analysis Properties of light measured by the spectral measuring device modified. The method of claim 9, wherein in the analysis the spectral properties of the spectral measuring device measured temperature, the temperature of an outer surface of a cast strand, which is arranged adjacent to the mold. The method of claim 10, wherein for modifying at least one execution variable the continuous casting process the withdrawal speed of a continuous casting machine is readjusted. A method according to claim 10, wherein the method is to modify at least one execution variable of the Continuous casting process that adjusts the speed with the heat of removed from the inner part becomes. Arrangement according to one of claims 1-6, wherein the outer surface of a smooth surface a thin one Layer of applied to a metal substrate material. Arrangement according to claim 14, wherein the thin layer has a conversion zone in which the composition of the below lying substrate metallurgically merges into the composition of said material.