EMAT SYSTEM FOR THE DETECTION OF SURFACE AND INTERNAL DISCONTINUITIES IN HIGH-TEMPERATURE CONDUCTIVE STRUCTURES

Abstract

An EMAT system (1) for detecting surface and internal discontinuities (2) in thick conductive structures (90) at high temperatures, comprising a magnet (4) that generates a static magnetic field (SMF) and a high-frequency electric coil (6) to induce, or be induced by, eddy currents in the material (14). It consists of an apertured array laminated magnetic core (22) positioned between the high-frequency electric coil (6) and the inspected material (3), which is formed by a multitude of apertured high-frequency active sheets (29) incorporating a ferromagnetic material, and apertured insulating passive sheets (53). Through-holes (41, 57) are drilled through each sheet (29, 53) and form a slotted cylindrical aperture (39). Parallel induced-current loops (43) surround each through-hole magnetic core (41) of the high-frequency active sheets (29).The cooling means (58) force a heat transfer fluid (60) to pass through the slotted cylindrical opening (39).

Description

EMAT SYSTEM FOR THE DETECTION OF SURFACE AND INTERNAL DISCONTINUITIES IN HIGH-TEMPERATURE CONDUCTIVE STRUCTURES TECHNICAL FIELD OF THE INVENTION This invention relates generally to ultrasonic non-destructive testing (UNDT) technology. It relates specifically to an electromagnetic acoustic transducer (EMAT) for UNT applications, its implementation methods, and its industrial applications. The technical field of the invention relates specifically to EMAT transducers: a. That they are non-vibratory type transducers, which do not vibrate mechanically, but induce and / or receive ultrasonic mechanical vibrations by electromagnetic means; b. To study or analyze materials using transmitting and / or receiving means adapted to induce ultrasonic waves in a conductive test body or to receive ultrasonic waves from this test body by electromagnetic means; and, to view the interior of objects by transmitting and / or receiving such ultrasonic waves emitted through the object; and, c. As such, belonging to International Patent Class No. G01N 29 / 24 and / or U.S. Patent Class No. 73 / 643. The technical scope of the invention is limited to EMAT transducers, which are also: a. Equipped with significant electromagnetic coupling means, located between the active electromagnetic parts of the transducer and the test body, to increase the coupling of a high-frequency magnetic field between the active electromagnetic parts of the transducer and the surface of the conductive test body through which eddy currents flow; and, b. Of the specific type whose electromagnetic coupling means consist of a laminated magnetic core, made up of an array of thin laminated sheets that internally incorporate a ferromagnetic or ferromagnetic material; and, c. Of the specific type, whose electromagnetic coupling means are equipped with active cooling means, to dissipate the thermal energy generated by the current loops induced in the periphery of the laminated thin sheets of its electromagnetic coupling means. The invention is preferably implemented in Laser-EMAT type equipment and / or in an EMAT-EMAT equipment, which combines both: an ultrasound generator consisting of a high-power pulse laser or an EMAT ultrasound generator, and an EMAT ultrasound receiver. ινΐΛ / a zuzq / uuz 1i ( The preferred use of the invention is the objective 3D physical scanning and non-destructive ultrasonic testing (UNDT) of high performance on the surface and internal discontinuities, in a production line of large structures, and / or thick structures, and / or components, manufactured from a conductive material, such as steel plates during their casting, in a highly industrial environment at a temperature above 1000°C. The invention can be used to automatically optimize the adjustment of the dynamic reduction (DNS) and / or dynamic secondary cooling (DSC) parameters of a continuous filament casting of a strand of steel plates in a steel mill, at a temperature greater than 1000°C. PREVIOUS TECHNIQUE EMAT technologies are used for the non-destructive testing of structures made of conductive materials under challenging conditions. Non-destructive testing (NDT) technologies are commonly used in industrial settings for structural control or inspection of structures and components of various shapes and sizes without damaging them. However, operating conditions and temperature, the type of implementation, and the size and structural complexity of the components being tested limit the number and types of NDT techniques available that can be used effectively and their applications.The raw data provided by state-of-the-art NDT systems are not suitable for sophisticated and in-depth defect detection and 3D location in large components treated under severe and / or extremely hot operating conditions at temperatures above 1000 °C, such as those encountered during continuous filament casting of steel plate strands in steel mills. Ultrasonic non-destructive testing (UNDT) is a family of NDT methods based on the propagation of ultrasonic waves within the object or equipment under test. In conventional UNDT testing, an ultrasonic probe connected to a diagnostic machine is passed over the object being inspected. Conventional UNDT methods use short-wavelength, high-frequency mechanical wave beams, transmitted from an ultrasonic generator probe through the material being tested, and detected by the same probe or another ultrasonic receiver probe, to identify structural defects in the component. The main probes used for UNDT testing are piezoelectric transducers, laser transducers, and electromagnetic acoustic transducers (EMATs). Conventional piezoelectric UNDT testing offers many advantages: safety, flexibility, and cost-effectiveness.However, piezoelectric testing has certain limitations, specifically: the need for a coupling; and the need for a good surface finish. It requires mechanical contact between the parts being tested and the probes. During hot part testing, finding a suitable coupling can be difficult. ML / a / ZUZ J / UUZ I í ! UNDT piezoelectric testing increases with temperature. In general, UNDT piezoelectric testing cannot be performed above 100 °C. The main aspect of the prior art of the invention relates to electromagnetic acoustic transducers (EMATs). Among UNDT technologies, the EMAT method is based on a magnetic coupling mechanism. Sound waves are generated within the material, not by contact with the surface of the test parts. EMATs offer significant advantages over conventional piezoelectric transducers. An EMAT can generate and receive different wave modes in conductive and ferromagnetic materials without physical contact or liquid coupling with the test parts. These contactless and coupling-free functionalities increase test reliability because the physical properties of the transmission path remain unchanged. Furthermore, the tolerance specifications required for the position and propulsion of the test parts against the EMAT probes are flexible.This makes conventional EMATs suitable for industrial applications involving average inspection temperatures (up to 600 °C) and poor surface conditions on moving parts being tested. There are two main components in an EMAT (Electrical Material Detector). One is a magnet, and the other is a high-frequency (HF) electrical coil. The magnet can be a permanent magnet or an electromagnet, which produces a static or near-static magnetic field. The electrical coil (or circuit) carries a high-frequency current. It emits or is induced by a high-frequency magnetic field. The EMAT phenomenon is reversible. Consequently, the same EMAT probe can be used as an ultrasonic emitter in an inspected material, or as an ultrasonic receiver for an ultrasonic signal emitted by an inspected material, or in a combination of both operating modes. The technique utilizes EMAT in a wide range of applications, including measuring the thickness of metal products, detecting defects in pipes, detecting defects in rails, detecting defects in steel products, and so on. It is common practice to attach a wear plate to an electronic material inspection (EMI) device to protect the magnet and the electrical coil circuit from wear caused by the EMI's movement against the material being inspected. The wear plate is typically positioned between the material being inspected and the EMI's active components, including the magnet and the electrical coil circuit. Common wear plates have the disadvantage of introducing paths of increased reluctance between the magnetically active part of the EMI device and the material being inspected. The main challenge of conventional EMAT technology is that EMAT probes suffer from low magnetic transduction efficiency for both static magnetic fields generated by magnets and high-frequency magnetic fields emitted or received. The state of ML / a / ZUZ J / UUZ I í ! The technique shows that by introducing a magnetic core, made of a high-permittivity ferromagnetic material, between a magnetic emitter and receiver, the intensity of the induced magnetic field can be increased hundreds or thousands of times. The magnetic core itself creates a magnetic field that adds to the emitted field. The amplification effect depends on the magnetic permittivity of the core material. It is also known that the interposition of a magnetic core can have negative side effects in the case of a high-frequency, variable magnetic field, related to the eddy currents generated in the core. These cause significant energy losses, which depend on the frequency of the high-frequency magnetic field.When the magnetic core consists of a single continuous piece, the high-frequency, variable magnetic field induces significant eddy currents. These currents are arranged in closed loops of electric current that traverse the entire cross-section of the magnetic core, perpendicular to the emitted high-frequency, variable magnetic field. Due to the material's resistance, these eddy currents cause significant power losses as a result of the Joule effect. For this reason, the prior art frequently employs a matrix-laminated magnetic core, which consists of a stack of thin active laminations made of a magnetically active, ferromagnetic material, separated by thin insulating passive laminations. These insulating passive laminations act as barriers against the eddy currents.Thus, eddy currents can only circulate in narrow loops, perpendicular to the emitted field, within the thickness of each thin, magnetically active sheet. Since the current in an eddy current loop is substantially proportional to the area of ​​its loop, a matrix-laminated magnetic core, according to the art, aims to minimize the area of ​​all eddy current loops, which are by nature perpendicular to the emitted high-frequency magnetic field. To overcome magnetic reluctance, U.S. Patent 7,546,770 B2 describes an EMAT (Electronic Magnetic Tester) that includes a laminated magnetic matrix core, configured as a sandwich matrix, comprising multiple thin ferromagnetically laminated sheets arranged in layers. Thin insulating sheets are sandwiched between the thin ferromagnetic sheets to form the sandwich matrix of the laminated magnetic matrix core. The EMAT is specifically and exclusively described in a configuration where the high-frequency (HF) electric coil is configured to induce eddy currents on the surface of the inspected material, not to receive them. Therefore, it should be noted that this prior art refers to and describes a probe configured as an EMAT transmitter only, and not as a receiver. The laminated magnetic core is positioned between the magnet and the inspected material.It is not arranged directly in front of the high-frequency electric coil. The entire outer surface of the laminated magnetic core is covered with a continuous conductive layer made of an electrically conductive material. It is known that an electric coil, which is coil-shaped and powered by an electric current, produces a beam of magnetic field lines, consisting of a multitude of magnetic field loops parallel to the axis of the circular spiral passing through the interior of the coil. The absolute intensity of each magnetic field loop is variable. It depends on its point of passage and its distance from the center of the coil. It is also known that an alternating high-frequency magnetic field loop produces eddy currents in a material located in the vicinity of its center, the direction of which is substantially perpendicular to the high-frequency magnetic field loop.Consequently, and although not described in any way in this prior art, it is understood that when this EMAT operates in high-frequency emission mode, its electric coil generates, in the direction of the magnetic core, a multitude of alternating high-frequency magnetic field loops of varying absolute intensities, passing through the center of the coil. The axis of the described electric coil is substantially parallel to the stacking plane of the thin laminations. The alternating high-frequency magnetic field loops are, therefore, substantially parallel to the stacking plane of the thin laminations of the laminated magnetic core. This induces a multitude of induced current loops, distributed only on the surface of the continuous conductive layer that completely envelops the laminated magnetic core.These induced current loops are topologically distributed on the surface of the conductive layer in a non-homogeneous, disorganized, continuous, and non-discrete manner. They have an absolute intensity that is variable and non-homogeneous, depending on their position within the continuous conductive layer. They are oriented substantially perpendicular to the stacking plane of the thin sheets. The induced current loops on the surface of the conductive layer are, therefore, substantially perpendicular to the ferromagnetically laminated thin sheets. As a result, no ferromagnetically laminated thin sheet is surrounded at its periphery by an induced current loop. The induced current loops on the surface of the conductive layer are mostly parallel to the surface of the inspected object. The laminated magnetic core of this prior art technique provides mechanical protection for the magnet and the high-frequency electric coil. It also provides improved transmission of the static magnetic flux from the magnet to the inspected material. This laminated magnetic core provides a global, but low, diffuse, and topologically non-homogeneous high-frequency coupling of the high-frequency magnetic field between the high-frequency electric coil and the eddy currents on the surface of the inspected material, opposite the probe and the high-frequency electric coil. The coupling of this high-frequency magnetic field is global and non-homogeneous, achieved by the continuous outer conductive layer, and not selectively and / or locally by each of the thin inner ferromagnetic laminations. According to this prior art, the high-frequency electrical coil is positioned above the magnet, at a considerable distance from the laminated magnetic core and the material being inspected. In this magnet arrangement, additional losses are generated during the transmission of high-frequency electromagnetic energy between the high-frequency electrical coil and the material being inspected. This arrangement of the laminated magnetic core of an EMAT minimizes flux leakage from the static magnetic field generated by the magnet. However, it degrades the quality of the high-frequency magnetic field coupling between the eddy currents on the surface of the material being inspected in front of the probe and the high-frequency electrical coil of the EMAT.This high-frequency magnetic coupling is of heterogeneous intensity between, on the one hand, the various local active fractions of the material facing each of the edges of each thin ferromagnetically laminated sheet and, on the other hand, the high-frequency electric coil. According to this prior art, the laminated magnetic core is thermodynamically passive. It does not include any active cooling means that can actively remove some of the thermal energy generated by the induced current loops on the surface of the ferromagnetically laminated thin sheets of the magnetic core. This EMAT, which is not actively thermally protected, cannot operate sustainably and reliably at temperatures above 600 °C. In a conventional EMAT, the protection of the active parts is ensured by an electromagnetically passive shielding plate made of insulating material, fixed to the working side of the transducer, separating its active parts from the material being inspected. The thickness of this shielding plate is the result of a compromise between mechanical strength, the required operating temperature, and the transduction efficiency of the EMAT. The technique also offers EMATs equipped with passive magnetic cores with gaps and not laminated. These magnetic cores are equipped with cooling media for high-temperature operation. However, these prior art EMATs do not combine a laminated magmatic core with internal cooling media, and they do not optimize or homogenize high-frequency magnetic coupling and / or effectively minimize high-frequency magnetic field leakage between the high-frequency electric coil and the inspected material. The reception of ultrasonic signals by an EMAT operating in receive mode works the same way as an EMAT operating in transmit mode. The receive direction of the EMAT operating in receive mode can be modified. This is achieved simply and purely electronically. This directivity allows for a high signal-to-noise ratio in an EMAT operating in receive mode. There has been very limited operation of state-of-the-art EMATs for inspection in a difficult industrial environment and / or under high temperature conditions above 1000°C, in order to perform continuous mobile online scanning of large areas of mobile plate-shaped structures from a single location, similar to that used at low temperature in the inspection of pipes and rails. A second aspect of the technique relates to Laser-EMAT UNDT technology, which improves the overall sensitivity of UNDT systems using an EMAT and their adaptability to operate at average temperatures up to 600°C. The UNDT phenomenon requires an ultrasound generator and an ultrasound receiver. A common Laser-EMAT system combines an ultrasonic generator made of a high-power pulsed laser and an EMAT operating in receive mode as an ultrasonic receiver. The technique describes such combined UNDT devices for detecting surface and subsurface discontinuities in a structure. They are based on the combined operation of i) an ultrasonic transmitter made of a pulsed laser that directs a laser beam toward the structure at an emission point, generating ultrasonic surface waves and shear waves in the structure when the pulsed laser beam radiation is absorbed by the structure; and ii) an ultrasonic receiver consisting of an EMAT operating in receive mode, detecting the ultrasonic surface waves and / or shear waves at a detection point.When a high-energy-density laser beam is directed at the surface of a component under test, such as a steel plate, the local pulse causes rapid heating, leading to a plasma explosion on the component's surface. This explosion generates ultrasonic waves throughout the component's material. The laser generates two distinct types of waves in the material. One propagates on or near the component's surface. This is the most significant detectable signal, propagating transversely across the component's surface. The other propagates deep within the material at a wide angle. When the component material is conductive, the EMAT ultrasonic receiver of the Laser-EMAT system is used to detect the ultrasonic signal generated in the test material by the combined effects of its high-frequency electric coil and magnet.Vibrations on the surface and within the material, initiated by the ultrasonic signal produced by the laser and influenced by the echoes of material discontinuities and their locations, induce a high-frequency electrical current in the detection circuit of the EMAT ultrasonic receiver through eddy currents generated in the inspected material. Surface and internal discontinuities of the component, located between the laser impact and the EMAT ultrasonic receiver, can thus be detected and located by processing the current signal in the high-frequency electrical coil, identifying changes and disturbances in the received ultrasonic signal caused by the discontinuities in the inspected material. These combined UNDT devices demonstrate better discontinuity detection efficiency than EMAT devices alone, which rely on EMATs used in both transmitter and receiver modes. This is because pulsed lasers are more efficient, directional, and powerful as ultrasonic sound emitters than conventional EMAT emitters. The main drawback of common laser-EMAT systems is that they retain the limitations and disadvantages of the common EMAT receiver they use, as previously mentioned. The laser beam can operate at elevated temperatures above 600°C, whereas conventional state-of-the-art EMATs cannot. A third aspect of the prior art of the invention relates to the optimized automatic adjustment of the Dynamic Smooth Reduction (DSR) parameters of continuous filament casting of steel parts at a temperature of approximately 1200°C, such as filament casting of steel plates and / or billets, in steel production. The steel plates are generally subsequently transformed into finished steel products, including sheets, plates, coils of metal strip, pipes, and tubes. During the solidification of the cast steel strand, between the solid and liquid phases of the metal, there is a region within the slab that is neither completely solid nor liquid. The fraction (percentage) of solid in this soft region depends on the thermal properties and composition of the steel. The volume of steel transformed from liquid to solid contracts due to the change in density associated with the decrease in the melting temperature. This contraction during solidification leads to voids in the interdendritic structure. A central segregation zone forms in the crater of the final solidification region.Internal segregation defects and porosity in the core of the plate structure, which occur during the continuous steel filament casting process, have an extremely negative effect on the properties of the finished steel products subsequently produced from the plate. This core segregation degrades the quality of steel products, particularly thick steel plates. It results in inconsistent mechanical properties and a potential for failure in the final steel products. There have been many attempts in the art to reduce or detoxify the central segregation of steel plates caused by defects that occur during continuous filament casting. A common practice to overcome this problem is to reduce the casting speed. Of course, this affects the overall flow rate of the casting. Another prior art practice involves applying soft reduction (SR) during the final solidification stage and / or dynamic secondary cooling (DSC). The basic idea behind any type of soft reduction (SR) is to suppress the formation of central macro-segregation and porosity by compensating for solidification shrinkage and interrupting the suction flow of residual steel.The SR operation must be performed with an appropriate reduction intensity and at the correct vertical angle of the soft zone of the final solidification stage, using pressure rollers or other similar specialized equipment. SR can only be performed where the center of the plate casting is not yet rigid. The optimum point is at the end of the solidification zone. The reduction intervals should be located between the two-phase solid-liquid zone and the end of the solidification of the filament casting of the plates to improve the density and homogeneity of the center of the row. The problem is that the exact position of this optimum point of completion of solidification is variable and unknown, as it is located in the center of the filament casting of steel plates and is therefore invisible according to prior art methods. In the Soft Solidification Reduction (LSR) method, a plurality of reduction rolls are arranged at various reduction intervals near the solidification completion point of the strand and the reduction zone of the slab casting during continuous strand casting. LSR is a method for gradually reducing void formation in the center of the molten strand and the molten mild steel stream. Static Soft Reduction (SSR), achieved by adjusting the fixed gap of the pressure rolls, was employed in the prior art to improve the internal quality of continuous strand casting of steel slabs. However, the placement of the pressure rolls at fixed reduction intervals is optimized and applicable only to a precise set of casting parameters. This means that the casting operation must be kept as stable as possible.The static reduction zone (SSR) imposes a constraint on general casting operations. Operational events make it difficult to maintain a constant state of filament casting parameters over extended periods. Casting parameters, such as melt rate and superheat, can change during the casting process. As a result, the solidification range shifts throughout the process. The operational efficiency of the SSR method is low. To achieve greater operational flexibility while maintaining good internal quality, the state of the art has proposed a dynamic soft reduction (DSR) system, which takes into account the transient conditions of filament casting, evolutionary solidification processes, and the behavior of the inspected material. It was found that DSR, combined or not with dynamic secondary cooling (DSC), is a more efficient means than SSR for minimizing segregation and porosity in the molten strands of slabs. MA.a.zuz j / uuz i í ! Steel. The parameters of Dynamic Soft Reduction (DSR) must be carefully defined to effectively eliminate center segregation and improve the internal quality of the cast plates. It is important to apply the soft reduction at the correct location and with precise separation of the pressure rolls during the solidification phase. If DSR occurs too early, the reduction simply deforms the outer faces of the plate and does not effectively penetrate the center. Applied too late, the plate is already completely solid and the resistance to deformation is too high, leading to excessively high loads on the equipment rolls. The main parameters influencing the reduction, which determine the efficiency of the Dynamic Soft Reduction (DSR) position, are the plate shape, the filament casting rate, the steel composition (thermal properties), superheat, and cooling rate.To achieve efficient smooth dynamic reduction (DSR), it is necessary to dynamically control the spacing of the pressure rollers, and preferably their position, according to the actual variable geometric state of the internal solidification process, given the current and historical conditions of the strand casting process. The accurate provision in time: i) of a dynamic 3D mapping (3DM) of the strand of the plate being cast, and / or ii) of the 3D location of the central segregation zone of the steel plates and / or the position of segregation defects; provided by a dynamic 3D mapping system (3DMS) of the foundry, are the basic requirements for the effective implementation of a dynamic soft reduction (DSR) and / or for an effective dynamic secondary cooling (DSC). State-of-the-art DSR / DSC systems generally comprise the following means: a. a dynamic 3D mapping system (3DMS) for steel casting; b. a computerized DSR optimization system (DSRM), which generates dynamic DSR optimization parameters (PCSD), based on the dynamic 3D mapping (3DM) provided by the 3DMS system and on the casting parameters; c. a digital DSR actuator (ASR), which dynamically adjusts the DSR action parameters (PASD), as a function of the PCSD generated by the DSRM; d. Optionally, a DSC optimization system (DSCM), which generates dynamic DSC optimization parameters (PCSC) based on the dynamic 3D mapping (3DM) provided by the 3DMS system and the casting parameters; e. Optionally, a digital DSC activator (ASC), dynamically adjusting the DSC action parameters (PASC) of the DSC water flow, based on the PCSC generated by the DSCM. ML / a / ZUZ J / UUZ I í ! The three important parameters of DSR reduction, such as the position and geometry of the reduction zone, the dynamics and reduction rate, and the value of the roller separation in the reduction section, must be thoroughly considered in the computer algorithm, DSRM optimization model. State-of-the-art dynamic 3D mapping systems (3DMS) for steel casting operate solely through simulation. They perform: a. a simulated numerical prediction based on theoretical algorithms; and based on a mathematical model of heat transfer and solidification in filament casting of plates; and, b. not by a physical detection of an actual dynamic 3D mapping (3DM) actually observed of the interior of the molten strand of the steel plate, with the precise location of the central soft zone, and the position of the discontinuities in the middle of the molten strand of the plate. A recent variant of a state-of-the-art dynamic 3D mapping system for steel casting (3DMS) is based in particular on an algorithmic interpretation of 2D thermal monitoring data of the exterior of the cast strand of plates, using a system implemented. None of the prior art dynamic 3D mapping systems (3DMS) for steel casting offer an accurate and reliable observed 3D mapping definition of discontinuities in the reduction / solidification zone of the molten strand of the slab, and / or the location of the mid-soft zone of the slab and / or segregation defects. Soft reduction DSR parameters, such as the position and geometry of the reduction zone, the dynamics and reduction rate, and the roll gap value in the reduction section, are currently adjusted based on information predicted from a theoretical model. This model is not observable and is often misleading regarding the mid-soft zone and the state of discontinuities within the molten strand of the slab. Therefore, DSR and / or DSC parameters are often inappropriate and ineffective in a continuous steel strand casting machine.They do not allow for the effective adjustment, through smooth dynamic reduction and / or properly adjusted secondary dynamic cooling, of segregation and excessive porosity of the center of the molten plate strand during the solidification process. TECHNICAL PROBLEM Analysis of the prior art reveals that a different approach is needed to solve, among other things, the following technical problem of Non-Destructive Ultrasonic Testing (UNDT): ινΐΛ / a zuz j / uuz 1i¡ a. Offering a combined solution to the following three technical problems in a single EMAT probe: i. Increase the transmission of high-frequency magnetic field energy, maximize high-frequency magnetic coupling and / or minimize high-frequency magnetic field flux leakage between the electric coil and the eddy currents generated on the surface of the inspected material; and, iii. Provide a surface topological homogeneity of the efficiency of this high-frequency electromagnetic coupling between the electric coil and the eddy currents on the surface of the inspected material in front of the probe; and, iii. Have an operational capability at elevated temperatures of the inspected material above 1000°C. b. Offering a combined solution to the following two technical problems in a single UNDT device: i. optimize the resolution of the detection of surface and deep subsurface discontinuities in a thick metallic structure; and, ii. have an operational capacity at high temperatures of the inspected material above 1000°C. c. Offering a 3D scanner of conductive structures, providing a combined solution to the following two technical problems: i. provide continuous line-by-line 3D scanning of large, thick, moving conductive structures, such as metallurgical plates, from a specific location, generating a high-resolution observed 3D map of this structure, including providing the location on the surface and deep discontinuities below the surface; and, ii. have the ability to operate in a harsh industrial environment, at elevated temperatures of the inspected material exceeding 1000°C. d. Enabling optimized automatic adjustment of the DSR (PASD) action parameters of dynamic soft reduction (DSR) and / or the DSC (PASC) action parameters of dynamic secondary cooling (DSC) of a continuous filament casting of steel plate strands in a steel mill, based on the observed state of the interior of the cast plate; solving in a single apparatus the combination of the following four technical problems: ινΐΛ / a zuz j / uuz 1i ¡ i. continuously provide a dynamic 3D mapping (3DM) actually observed of the interior of a fused plate strand; i. continuously defining in a 3D observed manner the location of the central soft zone of the plate strand and / or segregation defects, based on a 3D physical observation, and not provided simply by a numerical simulation prediction by a theoretical algorithm based on a mathematical model; iii. accurately detect the observed position of the reduction point of the molten plate strands, based on a 3D physical observation; iv. improving the accuracy and reliability of the automatic adjustment of the parameters of dynamic soft reduction (DNS) and / or dynamic secondary cooling (DSC), of a continuous filament casting of plate strands, at temperatures above 1000° C; in order to reduce segregation defects and porosity in the central soft zone in the melting of the steel plate strand structure during the continuous filament casting process in a steel mill. TECHNICAL SOLUTION Briefly, according to one aspect of the invention, an Electromagnetic Acoustic Transducer (EMAT) is provided for detecting surface and internal discontinuities in an electrically conductive material being inspected; this is to offer a technical solution to the aforementioned technical problem (a). Contrary to what is known to those skilled in the art, and unlike the conventional configuration of prior art EMATs using a laminated magnetic core, the technical solution of the invention consists in particular in that: a. The invention does not aim to reduce the area of ​​the eddy current loops within the active high-frequency laminations of the laminated magnetic core. On the contrary, the invention seeks to increase the area and effect of the induced current loops in the active high-frequency (ferromagnetic) laminations; but this is achieved in a configuration and orientation that are topologically organized to take advantage of it in order to improve the efficiency and homogeneity of the coupling, as well as the performance of the EMAT. b. The EMAT is not configured so that, in emission mode: i) the alternating high-frequency magnetic field loops induced by the high-frequency electric coil in the magnetic core are substantially parallel to the stacking plane of the thin laminated magnetic core laminations; and iii) a multitude of induced current loops are distributed only on the surface of a continuous conductive layer that completely envelops the laminated magnetic core and iii) the induced current loops are topologically distributed over the entire surface of the conductive layer in a non-homogeneous, non-organized, continuous and non-discrete manner, and iv) these induced current loops are oriented substantially perpendicular to the stacking plane of the thin laminations.However, on the contrary, according to the invention, the EMAT is configured so that in emission mode: i) the high-frequency alternating magnetic field loops induced by the high-frequency electric coil in the magnetic core are substantially perpendicular to the stacking plane of the thin laminates of the magnetic core; and ii) the induced current loops are located only on the periphery of the high-frequency active laminates and are oriented in a plane parallel to the plane of the high-frequency active laminates they surround on their periphery and are therefore perpendicular to the surface of the inspected object; and iii) the induced current loops are topologically distributed in a discrete and distant, but homogeneous manner over the periphery of the high-frequency active laminates; and iv) these induced current loops are thus oriented substantially parallel to the stacking plane of the thin laminates. c. The EMAT is not configured so that the active high-frequency leaves consist of a solid sheet. On the contrary, according to the invention, the active high-frequency leaves are perforated in their center by a through-hole, around which a current loop induced on the periphery of each active high-frequency leaf rotates perpendicular to its axis. d. The EMAT is not configured with a high-frequency electrical coil formed by a wound circuit, located away from the laminated magnetic core and separated from the magnetic core by a magnet, emitting in emission mode a variable high-frequency magnetic field flux of non-homogeneous absolute intensity in a continuous conductive layer surrounding all the active high-frequency laminations of the magnetic core. On the contrary, and in contrast, according to the invention, the EMAT is configured with an electrical coil made of a high-frequency meandering circuit composed of a succession of parallel portions of electrical conductors. The magnetic core is not covered by a continuous conductive layer. Each electrically conductive portion is traversed by an electric current of similar absolute intensity, but in the opposite direction to the neighboring electrically conductive portion.The electrically conductive portions alternately overlap directly above and over the upper edge of each high-frequency active lamination of the laminated magnetic core. In transmission mode, the high-frequency electrical coil emits in this way. ML / a / ZUZÓ / UUZ I í ! a high-frequency variable magnetic field flux of equivalent intensity in each active high-frequency sheet, and which is perpendicular to it. e. According to the invention, in emission mode, adjacent active high-frequency sheets are surrounded by counter-rotating induced-current loops. Thus, in successive portions of the material's surface facing each of the active high-frequency sheets of the laminated magnetic core, a variable high-frequency magnetic field flux is induced in opposite directions for each active high-frequency sheet, but with quasi-equal absolute intensity in each area facing an adjacent active high-frequency sheet. This induces an eddy current matrix on the surface of the inspected material facing the laminated magnetic core, formed by parallel vectors of substantially equal intensities but opposite directions. This topological configuration leads to higher EMAT resolution. BRIEF DESCRIPTION OF THE INVENTION The EMAT comprises: a. At least one magnet or electromagnet, configured to generate a static or quasi-static magnetic field in the inspected material; b. At least one high-frequency electric coil (or electrical circuit) operating at high frequency, the latter configured as a high-frequency electromagnetic transmitter of an emitted high-frequency electromagnetic field if the EMAT is used in transmission mode, and / or configured as a high-frequency electromagnetic receiver of an emitted high-frequency electromagnetic field if the EMAT is used in reception mode; c. At least one perforated matrix laminated magnetic core configured to concentrate and direct an emitted high-frequency electromagnetic field; made of the type comprising a (sandwich) matrix consisting of a multitude of laminated thin sheets, stacked periodically along the matrix axis. The sandwich array comprises a first multitude of high-frequency active sheets. These sheets are isolated from one another. Internally, they incorporate a magnetic material of high magnetic permeability. Each of these high-frequency active sheets either externally integrates an electrically conductive material and / or is externally coated with an electrically conductive layer on its peripheral edges. A slotted cylindrical opening passes through each thin sheet of the array and opens onto each of the two lateral faces of the array. A multitude of magnetic through-holes, of similar dimensions and cross-section, and with a closed lateral perimeter, are drilled through and substantially at the center of each of the multiple high-frequency active sheets of the array. They are aligned to form, by their alignment, the slotted cylindrical opening.A multitude of induced current loops are generated in the high-frequency active plates. The unique feature of this EMAT lies in the combination of the following technical means. Each Magnetic Through Hole, created in each open high-frequency active sheet, is located between the face of the first edge facing the inspected surface and the face of the second edge facing the high-frequency electrical coil. Each magnetic through hole in the slotted cylindrical opening is internally free of any hard material and is free of any electrical conductor passing through it. When the EMAT is in operation, induced current loops are created within the skin of the active sheet at the peripheral edges of the high-frequency active sheets. These loops are substantially parallel and separated from each other. They surround the magnetic through holes of their respective high-frequency active sheets and rotate around them. In one embodiment of the invention, a Laser-EMAT probe (LEMAT) is presented for the inspection of an Inspected Material, by receiving an ultrasonic signal emitted by said Inspected Material; to offer a technical solution to the above technical problem (b). This LEMAT includes: a. An EMAT according to the invention, as set forth above, configured in Receive Mode, to receive an ultrasonic signal from the Inspected Material; and b. A Laser Source configured to generate a high-energy laser beam at a Firing Point on the surface of the Inspected Material. The laser source generates ultrasonic waves, producing primary ultrasonic waves that propagate on the surface and / or within the inspected material. This generates secondary ultrasonic waves resulting from the echoes of interactions with discontinuities located on and / or within the inspected material. Depending on their location, these secondary waves also propagate on the surface and / or within the inspected material. This generates eddy currents in the inspected material, induced by the secondary ultrasonic waves under the influence of the static magnetic field emitted by the EMAT magnet. This, in turn, induces a high-frequency electromagnetic field emitted by the material from the eddy currents in the inspected material, which is representative of the surface topography and internal discontinuities of the inspected material. MA / a / zuz11 In another embodiment of the invention, a 3D Multi-Laser-EMAT (MLEMAT) scanner is presented for the detection of discontinuities on and within a movable cylindrical conductive structure; to offer a technical solution to the above technical problem (c). The MLMAT summarizes: a. A conductive structure to be 3D scanned; b. A chassis frame configured to surround the conductive structure; c. A multitude of Laser-EMAT (LEMAT) probes according to the invention, as indicated above, fixed to the Chassis Frame, positioned and configured such that each of the active faces of the first edge of each of its perforated matrix laminated magnetic cores faces the conductive structure; and, d. Displacement means configured to linearly move the cylindrical conductive structure in relation to the chassis frame. The peculiarity of this MLEMAT lies in the fact that the Loop of Openings, constituted by the virtual line that joins the centers of each successive Slotted Cylindrical Opening of each Perforated Matrix Laminated Magnetic Core of each of the adjacent EMATs of the MLEMAT, surrounds the Conductive Structure. In another embodiment of the invention, an adaptation of the Multi-LaserEMAT 3D scanner (MLEMAT) according to the invention, as indicated above, is presented for the automatic adjustment of the Dynamic Smooth Reduction (DSR) of a continuous filament casting of a strand of steel plates, at a melting temperature above 1000° C; and it offers a technical solution to the above technical problem (d). The steel plate strand is continuously pushed through a Dynamic Soft Reduction Device (DSRD) to suppress the formation of macro-segregation and porosity in the central soft zone within the steel plate strand. This dynamically compensates for solidification shrinkage and interrupts the suction flow of residual molten metal into the steel plate strand. The high-frequency electrical coils of each EMAT in each Laser-EMAT of the MLEMAT are connected to a Dynamic 3D Casting Mapping System (3DMS).This 3DMS is equipped with Analog and Digital Processing Means (ADMM) configured to combine and process the Secondary Ultrasonic Electrical Currents emitted in the Electrical Coils of each Laser-EMAT of the MLEMAT. These currents are induced in each high-frequency Electrical Coil of this Laser-EMAT by the Eddy Currents of the Material in the Front Zone of the inspected material of the steel plate strand. These Eddy Currents of the Material result from the interactions of the echoes generated by the Laser Sources with the ινΐΛ / a zuz j / uuz 1i(. Discontinuities on and within the inspected material in the front area of ​​the first edge face of this EMAT laser. The MDANs combine the secondary ultrasonic electrical currents of each EMAT and generate a dynamic 3D mapping (3DM) of the steel plate strand, in the strand structure section located in the frame plane, based on the combination and numerical analysis of these multiple secondary ultrasonic electrical currents in each EMAT laser of the MLEMAT. A DSR optimization system (DSRM) for the strand DSR is connected to the 3DMS. It receives the 3DM of the steel plate and digitally generates a set of dynamic DSR optimization parameters (PCSD). A digital DSR activator (ASR) is connected to the DSRM. It dynamically adjusts the DSR action parameters (PASD) based on the PCSD generated by the DSRM. The distinctive feature of this MLEMAT lies in the following combination of technical means. The cooling means of each of its EMATs, according to the invention, generate a cooling flow of a thermal fluid. This fluid is pushed into each magnetic track hole and each spacer track hole of the slotted cylindrical opening of each perforated matrix laminated magnetic core of each adjacent EMAT of the MLEMAT, at a cooling temperature (TF) significantly lower (at least 50°C) than the Curie temperature (TC) of the magnetic material of the open high-frequency active sheets. Thus, dynamic soft reduction (DSR) and / or dynamic secondary cooling (DSC) are automatically and dynamically adjusted at a melting temperature above 1000°C. BRIEF DESCRIPTION OF THE FIGURES These features, aspects, and advantages of the present invention, as well as others, will be better understood when the following detailed description is read with reference to the accompanying figures, in which similar characters represent identical parts throughout the figures, in which: Figure 1 is a schematic perspective representation of an EMAT transducer of the invention. Figure 2 is a schematic cross-sectional representation of an EMAT transducer of the invention. Figure 3 is a schematic perspective showing the operating mode of one of the high-frequency Active Sheets in the Perforated Matrix Laminated Magnetic Core of an EMAT transducer of the invention, used in Emission Mode. Figure 4 is a schematic perspective showing the operating mode of one of the high-frequency Active Sheets in the Perforated Matrix Laminated Magnetic Core of an EMAT transducer of the invention, used in Receive Mode. Figure 5 is a schematic perspective showing the Perforated Matrix Laminated Magnetic Core of an EMAT transducer of the invention, consisting of the stacking of its high-frequency Active Sheets and its Passive Sheets. Figure 6 is a partial schematic perspective view of the electromagnetic operation of the high-frequency Active Sheets of the Perforated Matrix Laminated Magnetic Core of an EMAT transducer of the invention, used in Emission Mode. Figure 7 is a schematic perspective of an alternative modality of some of the Thin Sheets of the Perforated Matrix Laminated Magnetic Core of an EMAT transducer of the invention, for dynamically lifting its Perforated Matrix Laminated Magnetic Core out of the Inspected Material. Figure 8 is a schematic cross-sectional view of a Laser-EMAT (LEMAT) probe according to the invention. Figure 9 is a schematic side view of a Multi Laser-EMAT (MLEMAT) 3D scanner according to the invention. Figure 10 is a schematic cross-sectional perspective of a Multi Laser-EMAT 3D Scanner (MLEMAT) according to the invention, for the automatic adjustment of Dynamic Soft Reduction (DSR) and / or Dynamic Secondary Cooling (DSC) of a continuous filament casting of Steel Plates, visualized at the level of its EMAT probes. Figure 11 is a schematic cross-sectional perspective of a Multi Laser-EMAT 3D Scanner (MLEMAT) according to the invention, for the automatic adjustment of Dynamic Soft Reduction (DSR) and / or Dynamic Secondary Cooling (DSC) of a continuous filament casting of Steel Plates, visualized at the level of its Laser sources. Figure 12 is a functional block diagram of a Multi Laser-EMAT 3D Scanner (MLEMAT) according to the invention, for the automatic adjustment of Dynamic Soft Reduction (DSR) and / or Dynamic Secondary Cooling (DSC) of a continuous casting of molten steel plate strands. DESCRIPTION OF THE MODALITIES The modalities described below are generally directed to an improved EMAT system (1), which can be used for Non-Destructive Testing (NDT) of a Conductive Structure (90) at a temperature above 1000 °C. ινΐΛ / azuzj / uuz 1i ¡ Referring to Figure 1 and Figure 3, we see an Electromagnetic Acoustic Transducer (EMAT) (1) for detecting surface and internal discontinuities (2) in an electrically conductive inspected material (3). Two magnets (4) are configured to generate a static or quasi-static magnetic field (SMF) in the inspected material (3). It is understood that each magnet (4) could be replaced by an electromagnet. A high-frequency electrical coil (6) (or electrical circuit) is placed directly above a perforated-matrix laminated magnetic core (22). Its winding plane (7) (or circuit plane) is parallel to the local inspected surface (8) of the inspected material (3) opposite the EMAT (1). The two magnets (4) are positioned on either side of the perforated-matrix laminated magnetic core (22). Referring to Figure 3, it can be seen that the EMAT (1) can be used in Emission Mode (EM). The high-frequency electrical coil (6) is configured as a high-frequency electromagnetic transmitter (9) of a high-frequency emitted electromagnetic field (HFEMF). It is connected to the output of at least one AC current source (11), driving a high-frequency alternating current (AC) at ultrasonic frequency into the high-frequency electrical coil (6). This induces the emitted high-frequency electromagnetic field (HFEMF) in the direction of the inspected material (3). The emitted high-frequency electromagnetic field (HFEMF) produces material eddy currents (14) on the surface of the inspected material (3). This generates ultrasonic Lorentz forces (15) in the inspected material (3) through the interaction of the material's eddy currents (14) with the static magnetic field (SMF).This can also generate magnetostriction if the inspected material (3) is ferromagnetic. The disturbance of the Lorentz forces (15) generates primary ultrasonic waves (17) directly in the inspected material (3). Referring to Figure 4, it is understood that the EMAT (1) can also be used in Reception Mode (RM). The high-frequency electrical coil (6) is then configured as a high-frequency electromagnetic receiver (18). It is traversed by a Secondary Ultrasonic Electrical Current (19) at ultrasonic frequency. This high-frequency current consists of secondary ultrasonic electrical signals (88) generated by an emitted high-frequency electromagnetic field (HFEMF) induced by the material's eddy currents (14). These eddy currents of the material (14) are produced on the inspected surface (8) of the inspected material (3) by secondary ultrasonic waves (21), under the influence of an external ultrasonic source, and interacting with the static magnetic field (SMF). These eddy currents of the material (14) are representative of the surface and internal discontinuities (2) of the inspected material (3). iniΛ / a zuzq / uuz 1i ( Referring again to Figure 1 and Figure 2, we see that a perforated matrix laminated magnetic core (22) is positioned between the inspected surface (8) of the inspected material (3) and the high-frequency electric coil (6), which is directly opposite it. The perforated matrix laminated magnetic core (22) is configured to concentrate and direct the emitted high-frequency electromagnetic field (HFEMF) toward and / or from the inspected material (3), depending on whether the EMAT (1) is in transmission or reception mode. It is of the type comprising a sandwich matrix (23) formed by a multitude of laminated thin sheets (24). These sheets are periodically stacked along the matrix axis (25), between the two main matrix faces (26) of the matrix (23), parallel to its stacking plane (27).The Perforated Matrix Laminated Magnetic Core (22) has multiple Edge Faces (35) with adjacent side grooves, which extend substantially perpendicular to the Stack Plane (27) and parallel to the Matrix Axis (25). Referring to Figure 2, we see that one of the Edge Faces (35), specifically the First Edge Face (36) of the Die (23), faces the Inspected Surface (8) of the Inspected Material (3). The other face, specifically the Second Edge Face (37) of the Die (23), is located substantially opposite the First Edge Face (36) and faces the high-frequency electrical coil (6). Referring to Figure 1 and Figure 5, we see that each laminated Thin Sheet (24) of the Array (23) has a spatial geometry and lateral dimensions similar to those of the adjacent Thin Sheets (24) in the Array (23). They have two main lateral Sheet Surfaces (32), each parallel to the Stacking Plane (27). With reference again to Figure 1 and Figure 5, it can be seen that the successive adjacent Peripheral Edges (33) of each Thin Sheet (24) form a Slotted Edge Surface (34) of the Matrix (23) that surrounds the Matrix Axis (25). The Core Axis (38) of the Matrix (23) substantially joins the centers of the First Edge Face (36) and the Second Edge Face (37). It is positioned substantially perpendicular to the Matrix Axis (25). Referring to Figure 5 and Figure 6, it can be seen that the Array (23) comprises a First Multitude (28) of high-frequency Active Sheets (29) (four are shown in the figures), or groups of such sheets. Each high-frequency Active Sheet (29) is isolated from the others. It internally incorporates a magnetic material (particularly ferromagnetic or ferromagnetic) with high magnetic permeability. The magnetic material has a certain Curie temperature (TC). Externally, it incorporates an electrically conductive material. Alternatively, it can be externally coated with an electrically conductive layer on its Peripheral Edges (33). A slotted cylindrical aperture (39) passes through each thin sheet (24) of the matrix (23), along an aperture axis (40) of the matrix (23), substantially parallel to the matrix axis (25) and perpendicular to the core axis (38). It opens onto each of the two faces of the matrix (26).A multitude of Magnetic Track Holes (41), of similar cross-sectional dimensions and with a closed perimeter, are drilled through and substantially in the center of each of the multiple high-frequency Active Sheets (29) thus hollowed out of the Array (23), along an axis substantially parallel to the inspected surface (8). They are aligned along an axis parallel to the inspected surface (8) to form, by their alignment, the slotted cylindrical opening (39). They possess a Longitudinal Track Hole Envelope (42), arranged along the Opening Axis (40) of the Array (23), the lateral perimeter of which is closed. Referring to Figure 3 and Figure 4, it can be observed that when the EMAT (1) is in operation, a multitude of closed Induced Current Loops (43) are induced by the Emitted High-Frequency Electromagnetic Field (HFEMF).The latter is emitted by the high-frequency alternating current (AC) at ultrasonic frequency in the high-frequency electric coil (6) when the EMAT is in emission mode, as shown in Figure 3; and / or is emitted by the ultrasonic frequency of eddy currents from the material (14) in the inspected material (3) when the EMAT is in reception mode, as shown in Figure 4. The eddy current loops (43) are located within the active sheet skin (48) on the periphery of each high-frequency active sheet (29) of the perforated matrix laminated magnetic core (22). As shown in Figure 6, they are arranged according to a loop mapping (LM), defining the topology, distribution, and relative positions of all the eddy current loops (43). With reference to Figure 2, the following characteristics of the EMAT (1) are observed. Each Magnetic Path Hole (41) in each high-frequency Active Sheet (29) is located between the First Edge Face (36) facing the Inspected Surface (8) and the Second Edge Face (37) facing the high-frequency Electrical Coil (6). Each Magnetic Path Hole (41) in the Slotted Cylindrical Opening (39) is internally free of any hard material. In particular, it is free of any electrical conductor passing through it. With reference to Figure 6, it can be observed that the Loop Mapping (LM) is topologically discrete and consists of a multitude of Induced Current Loops (43) in each high-frequency Active Sheet (29), (or groups of such Active Sheets) spaced apart from each other.With reference to Figure 3, it can be observed that the Induced Current Loops (43) (or group of such Loops) are induced within the Active Sheet Skin (48) at the Peripheral Edges (33) of the high-frequency Active Sheets (29). Each of them is arranged along a loop plane parallel to the stacking plane (27), and substantially perpendicular to the surface of the inspected material (3). They are substantially parallel to, and separated from, each other between their respective Active Sheets. ML / a / ZUZ J / UUZ I í ! high frequency (29). They surround the Magnetic Path Hole (41) of their high frequency Active Sheet (29) and rotate around it. With reference to Figure 6, it can be seen that each Core Spacing Slice (49) of the Perforated Matrix Laminated Magnetic Core (22) and its surface, located between two adjacent high frequency Active Sheets (29) (or group), is free from any Induced Current Loop (43), and more generally free from any induced electric current. Referring to Figure 3, it can be observed that the Emitted High-Frequency Electromagnetic Field (HFEMF) and the Perforated Matrix Laminated Magnetic Core (22) are configured such that, when the EMAT (1) is in operation, the High-Frequency Core Magnetic Field (HFIMF) has a significant component of the High-Frequency Core Transverse Magnetic Field (MFTHF), which is perpendicular to the stacking plane (27), perpendicular to each active high-frequency lamination (29), and substantially parallel to the surface of the inspected material (3). The high-frequency magnetic flux (MFHF) within the Perforated Matrix Laminated Magnetic Core (22) has a large component perpendicular to the core axis (38) and parallel to the surface of the inspected material (3). Therefore, it is not perpendicular to the inspected surface (8) of the inspected material (3).The closed Induced Current Loops (43) are generated by the High Frequency Core Transverse Magnetic Field (MFTHF) at the Peripheral Edge (33) of each High Frequency Active Lamina (29). Referring to Figure 5 and Figure 6, it is understood that a combined and interactive dual physical effect occurs within the Perforated Matrix Laminated Magnetic Core (22). On the one hand, each of the multiple parallel and topologically discrete Induced Current Loops (43) of each perforated High-Frequency Active Sheet (29) separately generates a high-frequency magnetic field. This separately and locally increases the discrete and selective high-frequency magnetic coupling between a narrow Local Active Fraction (44) on the inspected surface (8) opposite its First Edge Face (36) and the high-frequency electric coil (6). The parallel Induced Current Loops (43) of the high-frequency Active Sheet (29) participate in the overall reduction of the high-frequency magnetic reluctance of the EMAT (1).On the other hand, the inner perimeter (45) of each magnetic pathway hole (41) in each high-frequency active sheet (29) of the array (23) creates a conductive and convective heat surface (46) at the center of its high-frequency active sheet (29). This produces an internal thermal cooling effect to dissipate a fraction of the local electrical and heat energy generated by the specific induced current loop (43) of each high-frequency active sheet (29). This contributes to improving the efficiency of the EMAT (1). Referring to Figure 5, we see the Perforated Matrix Laminated Magnetic Core (22), with its high frequency Active Laminates (29) separated by Passive Laminates (53). ML / a / ZUZ J / UUZ I í ! Each high-frequency active foil (29) of the array (23) (or group of such active foils) is separated from its neighbors, at the level of the adjacent core spacing slices (49), by at least one foil of a second multitude (54) of passive foils (53) of electrically insulating material. Each passive foil (53) is perforated by a spacing via hole (57). Each passive foil (53) is positioned and configured such that the magnetic vias (41) in the first multitude (28) of high-frequency active foils (29) of the array (23), as well as the spacing via holes (57) of the second multitude (54) of passive foils (53) of the array (23), are aligned parallel to the axis of the array (25). Their alignment and combination form the Slotted Cylindrical Opening (39). This Electromagnetic Acoustic Transducer (EMAT) configuration (1) has the following characteristics. Each Spacer Via Hole (57) in each Passive Sheet (53) is located between the First Edge Face (36) facing the Inspected Material (3) and the Second Edge Face (37) facing the High-Frequency Electrical Coil (6). Each Spacer Via Hole (57) in the Slotted Cylindrical Opening (39) is internally free of any hard material. In particular, it is free of any electrically conductive material passing through it. It is understood that the internal periphery of each Spacer Via Hole (57) in each Passive Sheet (53) of the Array (23) creates a free, internal Heat Conductive and Convective Surface (46) at the center of the Passive Sheet (53).This produces an internal thermal cooling effect in this spacer track hole (57) to dissipate a fraction of the electrical and heat energy generated by the induced current loops (43) of the adjacent high-frequency active plates (29). This contributes to the improvement of the EMAT efficiency (1). As shown in Figure 5, the invention recommends that, for each Passive Laminate (53), the Peripheral Edges (33) of its periphery be free of any conductive material covering its surfaces. Thus, the slotted Edge Surface (34) of the Perforated Matrix Laminated Magnetic Core (22) is not continuously coated and / or constituted by an electrically conductive layer, but rather consists of alternating edges, formed on one side by conductive rings around the high-frequency Active Laminates (29) and on the other side by insulating rings around the Passive Laminates (53). According to a preferred embodiment of the invention, shown in Figure 5, the Perforated Matrix Laminated Magnetic Core (22) of the EMAT (1) comprises Cooling Means (58). These generate a Cooling Flow (59) of a Heat Transfer Fluid (60) at a Cooling Temperature (TF). This Cooling Flow (59) is forced to pass through the Slotted Cylindrical Opening (39) of the Matrix (23). This configuration of the EMAT (1) has the following characteristics. The Cooling Flow (59) is configured to pass successively through one of the Magnetic Track Holes (41) of the First Crowd (28) and, alternatively, through at least one of the Sword Track Holes (57) of the Second Crowd (54). Absorbs all Hole Wall Surfaces (62) of each successive Magnetic Track Hole (41) and / or of each Sword Track Hole (57) of the Array (23).It is understood that this increases the internal thermal cooling effect in each High-Frequency Active Lamina (29) of the Array (23); each of which is subject to an Induced Current Loop (43) and heat dissipation. The invention recommends that the cooling temperature (TF) of the cooling flux (59) be set significantly lower (by at least 50°C) than the specific Curie temperature (TC) of the magnetic material of each open High-Frequency Active Lamina (29). Referring to Figure 7, an advantageous alternative embodiment of the EMAT (1) of the invention is shown. At least one (and preferably a multitude of) Thin Sheet(s) (24) of the Perforated Matrix Laminated Magnetic Core (22) is either perforated by a Damping Hole (63) or provided with a Damping Notch (64). These openings pass through the Annular Wall (65) formed between its Track Holes (41, 57) and the portion of its First Edge Face (36) facing the Inspected Material (3), in a direction parallel to the Stacking Plane (27). This creates a Damping Recess (66) between the Track Holes (41, 57) of the thin sheet (24) and the First Edge Face (36) facing the inspected material (3). The Cooling Means (58) are configured to extract a Damping Fluid Flow (67) from the Cooling Flow (59) passing through the Way Holes (41, 57).This extracted damping fluid flow (67) flows under pressure through the damping recess (66). This creates a lifting air damper (70) between the perforated die-laminated magnetic core (22) and the inspected material (3), at the level of the damping recess (66) opposite the inspected material (3). This raises the perforated die-laminated magnetic core (22) above the inspected material (3) by a damping gap (68). This arrangement is reliable. It provides automatic mechanical adjustment of the damping gap (68). It is understood that this arrangement considerably reduces the heat energy transferred by conduction between the inspected material (3) and the perforated die-laminated magnetic core (22), as well as to the active parts. This arrangement eliminates friction. It significantly increases the operating time and availability of the EMAT (1), by limiting wear between maintenance phases. Referring to Figure 5, a variant of the EMAT (1) of the invention is shown. The two outer lateral Edge Faces (35) of the two outer Thin Sheets located on the Matrix Faces (26) are constituted or covered by (as illustrated) a Conductive Coating Layer (69) of an electrically conductive material. This configuration of the EMAT (1) has the following characteristics. A track hole with transverse dimensions similar to those of the magnetic track holes (41) is drilled through each of the two conductive coating layers (69). The multiple Thin Sheets (24) and the two conductive coating layers (69) of the Matrix (23) are positioned relative to each other such that their multiple track holes are aligned to form, by continuity, the Slotted Cylindrical Opening (39). According to a preferred embodiment of the invention, described in Figure 5, the perimeter of each Magnetic Track Hole (41) formed in each High-Frequency Active Sheet (29) is rectangular. The center of each Magnetic Track Hole (41) is substantially located and centered at the center of gravity of its High-Frequency Active Sheet (29). The perimeter of each Magnetic Track Hole (41) is positioned substantially at a constant Ring Distance (Rd) from the perimeter of the Peripheral Edges (33) of its High-Frequency Active Sheet (29). It is understood that, in such a configuration, each High-Frequency Active Sheet (29) is topologically configured as a rectangular Active Ring (71), thermodynamically cooled by the heating of the Induced Current Loop (43) generated around it. Referring to Figure 1 and Figure 2, a preferred embodiment of the EMAT (1) of the invention is shown. The face of the second edge (37) of the perforated matrix laminated magnetic core (22) faces directly toward the high-frequency electric coil (6). No magnet (4) or any other element is positioned between the face of the second edge (37) of the matrix (23) and the high-frequency electric coil (6). Referring to Figure 6, another preferred embodiment of the EMAT (1) of the invention is shown. The high-frequency electric coil (6) and the first array (28) of high-frequency active sheets (29) in the array (23) are configured such that: the orientation, pitch, size, and shape of each of the circuit-facing edges (72) of each high-frequency active sheet (29), located on the face of the second edge (37) of the array (23), and facing the high-frequency electric coil (6), are consistent and correlated with the geometric parameters, including the orientation, pitch, size, and shape, of the conductive fractions (75) of the high-frequency electric coil (6) successively facing each of these circuit-facing edges (72). A preferred arrangement of the above configuration is shown with reference to Figure 3. It can be observed that the high-frequency electrical coil (6) has at least a fraction of the linear conductor (73). The latter is located in close proximity to and directly above a circuit-facing edge (72). It is tangent, along an axis parallel to this portion near the perimeter of a high-frequency active sheet (29) located on the face of the ML / a / ZUZÓ / UUZ I í ! Second Edge (37) of the Matrix (23) facing the high-frequency electric coil (6). It can be observed that a particularity of this arrangement of the invention is that the Linear Conductive Fraction (73) and the Laminated Perforated Matrix Magnetic Core (22) are configured in such a way that, when the EMAT (1) is in operation, an Induced Current Loop (43) is generated that is induced in the Active Sheet Skin (48) on the periphery of the High-Frequency Active Sheet (29). It surrounds its Magnetic Path Hole (41).This provides a selective local high-frequency magnetic coupling between, - on the one hand, a high-frequency Alternating Current (AC) driven in the linear conductive fraction (73) that extends over and along the perimeter of the high-frequency Active Sheet (29), and, - on the other hand, the Material Eddy Currents (14) generated in the narrow Local Active Fraction (44) of the Inspected Surface (8) that is in front of the high-frequency Active Sheet (29). The emitted high-frequency electromagnetic field (HFEMF) from a fraction of a linear conductor (73), through which an electric current flows, is known to be orthoradial. Consequently, the high-frequency magnetic flux lines (HFMF) are substantially formed by circles surrounding the fraction of the linear conductor (73). If the EMAT (1) is in emission (EM) mode, as described in Figure 3, then the high-frequency alternating current (AC) flowing through the linear conductive fraction (73) produces an orthoradial magnetic flux organized in a loop, generating a high-frequency magnetic flux loop from the conductive fraction (76). This creates a high-frequency transverse magnetic field (MFTHF) from the core, which is substantially perpendicular to the high-frequency active sheet (29) facing it. This induces an induced current loop (43) on the surface of the active ring (71) of the high-frequency active sheet (29).This induced current loop (43) in turn emits a multitude of high-frequency magnetic flux loops that produce eddy currents from the material (14) that are topologically ordered and all oriented along an axis substantially parallel to the plane of the high-frequency active sheet (29) facing them in the immediate vicinity above. It is also known that a circular loop powered by a current produces a beam of magnetic field lines, in the form of a multitude of magnetic flux loops parallel to the axis of the circular loop and passing through its center. With reference to Figure 4, it is understood that when the EMAT (1) is used in Reception Mode (RM), the component of the Material (14) eddy currents parallel to the stacking plane (27), generated on the material surface under the influence of an external ultrasonic source, induces a high-frequency magnetic flux loop in the Material (77), creating a high-frequency transverse magnetic field (MFTHF) substantially perpendicular to the active ring (71) of the high-frequency active sheet (29) facing these eddy currents in the Material (14). This creates an induced current loop (43) within its active sheet skin (48).The Induced Current Loop (43) longitudinally surrounding this high-frequency Active Sheet (29) then emits a multitude of high-frequency magnetic flux loops surrounding the Linear Conductive Fraction (73) that is tangent to it along an axis parallel to a portion of the perimeter of this high-frequency Active Sheet (29). This inductively generates a Secondary Ultrasonic Electrical Signal (88) that creates a high-frequency Alternating Current (AC) in the Linear Fraction (73). According to a preferred embodiment of the invention shown in Figure 3 and Figure 6, the high-frequency electrical coil (6) is a meander circuit (74). It has multiple (at least two) linear conductive fractions (73) (four are shown in Figure 6). These fractions are parallel and adjacent to one another. These linear conductive fractions (73) of the meander circuit (74) are successively positioned in close proximity to, and directly above, a circuit-facing edge (72) of one of the high-frequency active sheets (29), located on the second face edge (37) of the array (23) opposite the high-frequency electrical coil (6). They are configured so that the high-frequency Alternating Current (AC) that passes successively through each of the parallel and adjacent Linear Conductive Fractions (73) of the Meander Circuit (74) is oriented in alternating opposite directions.It can be seen that a high-frequency magnetic flux loop of the conductive material (76) substantially perpendicularly surrounds each fraction of the linear conductive material (73) of the meander circuit (74) and penetrates substantially perpendicularly into the high-frequency active sheet (29) opposite it. It can also be seen that this arrangement comprises the following features. The fractions of the linear conductive material (73) of the meander circuit (74) and the perforated matrix laminated magnetic core (22) are configured such that when the EMAT (1) is in emission mode (EM), two adjacent high-frequency active sheets (29), capped by two adjacent fractions of the linear conductive material (73), are traversed in their active sheet skin (48) by two adjacent induced current loops (43).Each of them is composed of a high-frequency alternating electric current that rotates in an opposite direction of rotation (78), around the aperture axis (40) that passes through its magnetic track holes (41), one clockwise, while the other is counterclockwise. Referring to Figure 1, it can be seen that the Opening Depth (Od) of the Slotted Cylindrical Opening (39) of the Perforated Matrix Laminated Magnetic Core (22), along its Opening Axis (40), is substantially equal and consistent with a First Transverse Dimension (FTd) of the High Frequency Electric Coil (6) of the EMAT (1). ινΐΛ / a zuz j / uuz 1i¡ Furthermore, the face of the second grooved edge (37) of its perforated matrix laminated magnetic core (22), opposite the high-frequency electric coil (6), has a transverse dimension, in a direction perpendicular to the opening axis (40) of the sandwich (23), which is substantially equal to and consistent with a second transverse dimension (STd) of the high-frequency electric coil (6) of the EMAT (1). According to a preferred embodiment of the invention, shown in Figure 5, the geometric dimensions of the sheet (79) of the perforated thin sheets (24) of the matrix (23) and the combined geometric dimensions of its perforated matrix laminated magnetic core (22) are selected to be uncorrelated with the wavelengths of the main harmonics of the emitted high-frequency electromagnetic field (HFEMF). It is understood that this prevents mechanical resonance of its perforated matrix laminated magnetic core (22) at the ultrasonic operating frequency of the EMAT (1). According to another preferred embodiment of the invention, the Geometric Sheet Dimensions (79) of the perforated Thin Sheets (24) of its Perforated Matrix Laminated Magnetic Core (22) are chosen such that, at the ultrasonic operating frequency of the EMAT (1), they are much smaller than the wavelengths of the ultrasonic waves generated in these thin sheets (24), or substantially equal to an odd number of quarters of the wavelengths of the ultrasonic waves generated in these thin sheets (24). According to another preferred embodiment of the invention, described in Figure 2, the first slotted face of the first edge (36) of the perforated matrix laminated magnetic core (22), facing the inspected material (3) and parallel to the slotted cylindrical opening (39), is covered by, or coated with, an insulating layer (81) (as illustrated) made of an electrically insulating material. One side of the insulating layer (81) is disposed opposite the slotted cylindrical opening (39) and covers the edge of the face of the first edge (36), belonging to the perimeter of each of the high-frequency active sheets (29). The EMAT (1) of the invention, and its variants explained above, offer a technical solution to the aforementioned technical problem (a). This EMAT (1) increases the transmission of energy from the emitted high-frequency electromagnetic field (HFEMF). It maximizes high-frequency magnetic coupling and minimizes flux leakage of the emitted high-frequency electromagnetic field (HFEMF) between the high-frequency electric coil (6) and the eddy currents of the material (14) generated on the surface of the inspected material (3). It ensures topological homogeneity on the surface of the inspected material (3) in terms of the efficiency of this high-frequency electromagnetic coupling between the high-frequency electric coil (6) and the eddy currents of the material (14) in front of the transducer. It operates at high temperatures of the inspected material (3) exceeding 1000°C. ινΐΛ / azuzj / uuz 1i ¡ Referring to Figure 8, a Laser-EMAT probe (LEMAT) (82) is shown for inspecting an inspected material (3) by receiving an ultrasonic signal from said inspected material (3). The LEMAT comprises the combination of: i) an Electromagnetic Acoustic Transducer (EMAT) (1) according to the invention as described above, and ii) a Laser Source (84). The EMAT (1) is configured in Receive Mode (RM) to receive a Secondary Ultrasonic Electrical Signal (88) from the Inspected Material (3). The high-frequency Electrical Coil (6) is configured as a high-frequency Electromagnetic Receiver (18). As shown in Figure 4, this Secondary Ultrasonic Electrical Signal (88) is electrically induced by a High Frequency Electromagnetic Field (HFEMF) emitted by the Inspected Material (3), generated by the Material's Eddy Currents (14), produced in the Inspected Material (3) by the Secondary Ultrasonic Waves (21).These eddy currents of the material (14) are representative of the surface and / or internal discontinuities (2) of the inspected material (3). As shown in Figure 8, the Perforated Matrix Laminated Magnetic Core (22) is located between the high-frequency electric coil (6) of the EMAT (1) and the local surface of the inspected material (3). It is directly opposite the high-frequency electric coil (6). It maintains a protective gap (83) between the inspected material (3) and the high-frequency electric coil (6). It reduces the magnetic reluctance of the EMAT (1). It is actively thermodynamically protected from the high temperatures and harsh surface conditions of the inspected material (3). The laser source (84) is configured to draw a high-energy laser beam (85) onto a firing point (86) on the surface of the inspected material (3).The laser beam (85) generates primary ultrasonic waves (17) propagating on the surface and / or within the inspected material (3). This causes the generation of secondary ultrasonic waves (21) resulting from the echoes of the interactions of the primary ultrasonic waves (17) with the discontinuities (2) on and / or within the inspected material (3). These secondary ultrasonic waves (21) propagate on the surface and / or within the inspected material (3). They cause the generation of eddy currents (14) on the surface of the inspected material (3), induced by the mechanical vibrations of the secondary ultrasonic waves (21) under the influence of the static magnetic field (SMF) generated by the magnet (4) of the EMAT (1).This induces a high-frequency emitted electromagnetic field (HFEMF) from the material's eddy currents (14) present on the surface of the inspected material (3), representative of the geometry and position of surface features and internal discontinuities (2) of the inspected material (3). Processing this high-frequency emitted electromagnetic field (HFEMF) through the EMAT (1) generates the secondary ultrasonic electrical signal (88) in the high-frequency electrical coil (6). ινΐΛ / a zuz j / uuz 1i¡ Referring to Figure 4, with the EMAT (1) configured in Receive Mode, the Laser-EMAT Probe (LEMAT) (82) is found to have the following technical characteristics. A multitude of remote eddy current loops (43) are induced by the emitted high-frequency electromagnetic field (HFEMF) from the material's eddy currents (14) in the inspected material (3) under the influence of the laser source (84), within the Active Sheet Skin (48) at the peripheral edges (33) of each high-frequency active sheet (29) of the perforated matrix laminated magnetic core (22). As shown in Figure 6, these eddy current loops (43) of each high-frequency active sheet (29) (or group) are separated from each other. These eddy current-induced loops (43) surround and rotate around the magnetically active ring (71), surrounding the magnetic passage holes (41) of the high-frequency active sheets (29).They are located between the First Edge Face (36) facing the Inspected Material (3) and the Second Edge Face (37) facing the High Frequency Electric Coil (6). They are positioned substantially perpendicular to these two Edge Faces (36, 37). It is understood that in said LEMAT (82), a combined and interactive double physical effect occurs within the Laminated Magnetic Core of Perforated Matrix (22). On the one hand, as shown in Figure 4, each of the multiple discrete and parallel induced current loops (43) of each open high-frequency active lamination (29) (or group) separately generates a high-frequency magnetic field. This separately and locally increases the high-frequency magnetic coupling between a Local Active Fraction (44) of the Inspected Surface (8) opposite the First Edge Face (36) and the high-frequency electric coil (6). This homogenizes the high-frequency coupling and, through mutualization, contributes to the overall reduction of the high-frequency magnetic reluctance of the EMAT (1).On the other hand, as shown in Figure 5, the inner perimeter (45) of each magnetic pathway hole (41) in each high-frequency active sheet (29) of the array (23) creates a free internal heat-conducting and convective surface (46) at the center of its high-frequency active sheet (29). This produces an internal thermal cooling effect to dissipate a fraction of the electrical and heat energy generated by the induced current loop (43) of its specific high-frequency active sheet (29). This contributes to improving the efficiency of the EMAT (1). The LEMAT (82) of the invention offers a technical solution to the above technical problem (b). It optimizes the resolution of the detection of discontinuities on the surface, below the surface, and deep below the surface (2) in a thick metallic structure. It operates at elevated temperatures of the inspected material (3) exceeding 1000°C. Referring to Figure 9, a 3D Multi-Laser-EMAT (MLEMAT) scanner (89) is shown, for the detection of surface and / or internal discontinuities (2) within a movable cylindrical conductive structure (90). The MLEMAT (89) comprises: a) a ML / a / ZUZÓ / UUZ I í ! Conductive Structure (90) to be 3D scanned; b) a Chassis Frame (93); c) a Probe Array (96) comprising at least two Laser-EMAT (LEMAT) Probes (82) according to the invention; and d) Displacement Means (97). The 3D scanned conductive structure (90) is made of an electrically conductive inspected material (3). It has a cylindrical structure generated along a Structure Axis (91), and a substantially constant Structure Section (92). The chassis frame (93) is configured to surround the structure (90) at a distance from the frame (Fd). Its Frame Plane (95) is substantially perpendicular to the Structure Axis (91) of the Conductive Structure (90). The Displacement Means (97) are configured to linearly move the cylindrical Conductive Structure (90) relative to the Chassis Frame (93), along a Displacement Direction (Md), substantially coincident with the Structure Axis (91). This 3D Multi-Laser-EMAT (MLEMAT) scanner (89) has the following feature which appears with reference to Figure 10, the Loop of Apertures (99), constituted by the virtual line that joins the centers of each successive Slotted Cylindrical Aperture (39) of the Perforated Matrix Laminated Magnetic Core (22) of each adjacent EMAT (1) of the Laser-EMAT (LEMAT) Probe (82) of the MLEMAT (89), surrounds the Conductive Structure (90). It is also seen that the multitude of probes (96) made of Laser-EMAT probes (82) are fixed to the chassis frame (93), positioned and configured such that the juxtaposition of the multitude of adjacent first edge faces (36) that are neighboring the perforated matrix laminated magnetic cores (22) of each of the adjacent Laser-EMAT (LEMAT) probes (82), facing the inspected material (3), are substantially contiguous with each other, and this constitutes a substantially continuous slotted inspection ring (100). This slotted inspection ring (100) surrounds and covers the perimeter of the conductive structure (90), in a structural section (92) of the conductive structure (90) close to the frame plane (95). In a preferred embodiment of the Multi-Laser-EMAT (MLEMAT) 3D scanner (89), shown with reference to Figure 11, the Laser Source (84) of each MLEMAT (82) consists of an Optical Fiber (101), fixed to the Frame Plane (95), which has a Firing End (102) facing the Conductive Structure (90). Each Optical Fiber (101) is connected to a Laser Generator (103). This configuration of the Multi-Laser-EMAT (MLEMAT) 3D scanner (89) has the following feature. The Laser Firing Loop (104), formed by the virtual line joining the Firing Ends (102) of each adjacent Laser-EMAT (LEMAT) Probe (82) of the MLEMAT (89), surrounds the Conductive Structure (90) and is substantially parallel to the Aperture Loop (99). In a preferred alternative embodiment of the Multi-Laser-EMAT (MLEMAT) 3D scanner (89) of the invention, it is operated for the detection of surface and / or internal discontinuities (2) of a metallurgical plate (105). The conductive structure (90) is then a cylindrical metallurgical plate (105) that is movable with respect to the MLEMAT (89). The aperture loop (99), constituted by the virtual line joining the centers of each successive slotted cylindrical aperture (39) of the perforated matrix laminated magnetic core (22) of each adjacent EMAT (1) of the Laser-EMAT (LEMAT) probes (82) of the MLEMAT (89), surrounds the movable cylindrical metallurgical plate (105). In another preferred implementation of the Multi-Laser-EMAT (MLEMAT) 3D scanner (89) of the invention, it is used for the detection of surface and / or internal discontinuities (2) of a movable cylindrical bead cast from metallurgical plate (105), continuously melted into filaments in a steel mill at a melting temperature (TS) above 1000 °C. The high-frequency apertured active laminations (29) of each perforated matrix laminated magnetic core (22) of each adjacent EMAT (1) of the MLEMAT (89) are made of a magnetic material, for example, of the ferromagnetic or ferromagnetic type, having a Curie temperature (TC) below the melting temperature (TS). This Multi-Laser-EMAT (MLEMAT) 3D scanner (89) has the following characteristics.As shown in Figure 10, each Slotted Cylindrical Opening (39) of each Perforated Matrix Laminated Magnetic Core (22) of each EMAT (1) of each adjacent LEMAT (82) of the MLEMAT (89) is connected to Cooling Media (58), generating a Cooling Flow (59) of a Heat Transfer Fluid (60). The heat transfer fluid (60) is pushed under pressure into each via hole (41, 57) of the slotted cylindrical opening (39) of each perforated matrix laminated magnetic core (22) of each adjacent EMAT (1) of the MLEMAT (89), at a Cooling Temperature (TF) significantly lower (at least 50°C) than the Curie Temperature (TC) of the high-frequency active sheet magnetic material (29). The MLEMAT (89) of the invention, and its variants detailed above, offer a technical solution to the above technical problem (c). This MLEMAT performs a continuous 3D scan of the line of large, thick, mobile conductive structures (90), such as metallurgical plates (105), from a single location, generating a high-resolution observed 3D map of this structure, even providing the location of discontinuities on the surface and deep beneath the surface (2). It operates at high temperatures of the inspected material (3) exceeding 1000°C. Referring to Figure 12, the Multi-Laser-EMAT (MLEMAT) 3D scanner (89) according to the invention, as previously described, is configured for the automatic adjustment of the dynamic parameters of the Dynamic Soft Reduction (DSR) of the filament casting of the steel plate (105) continuously melted in a steel mill at a filament casting temperature (TS) above 1000°C. The molten strand of the steel plate (105) is continuously pushed through a dynamic soft reduction device (DSRD) to suppress the formation of a macro-segregation zone and porosity zones within the molten strand of the steel plate (105); thus dynamically compensating for the solidification shrinkage of the steel and interrupting the suction flow of residual molten metal in the Central Soft Zone (106) of the steel plate (105). This MLMAT (89) is coupled to a Dynamic Soft Reduction Device (DSRD) comprising: i) a Dynamic 3D Mapping System (3DMS), generating a Dynamic 3D Mapping (3DM) of the cast strand of the Steel Plate (105); ii) a computerized DSR Optimization System (DSRM), generating Dynamic DSR Optimization Parameters (PCSD), based on the Dynamic 3D Mapping (3DM) and the strand filament casting parameters; and iii) a Digital DSR Activator (ASR), dynamically adjusting the DSR Action Parameters (PASD) of the Dynamic Soft Reduction Device (DSRD), based on the PCSD generated by the DSRM. This 3D Multi-Laser-EMAT (MLEMAT) scanner (89) has the following characteristics. The high-frequency electrical coils (6a, 6b, 6) of each EMAT (1a, 1b, 1) of each LaserEMAT (82a, 82b, 82) of the MLEMAT (89) are each connected to the Dynamic 3D Mapping System (3DMS). They transmit a Secondary Ultrasonic Electrical Signal (88a, 88b, 88) induced in each high-frequency electrical coil (6a, 6b, 6) by the eddy currents of the material (14) in the front zone (110) of the inspected material (3) of the steel plate (105) locally in front of each EMAT (1a, 1b, 1). The DSR optimization system (DSRM) has analog and digital processing means (MDAN). The MDANs are configured to receive the multitude of secondary ultrasonic electrical signals (88a, 88b, 88) included in the secondary ultrasonic electrical currents (19a, 19b, 19) that pass through each high-frequency electrical coil (6) in each Laser-EMAT (82a, 82b, 82) of the MLEMAT (89).The MDANs are also configured to identify changes and disturbances in each Secondary Ultrasonic Electrical Signal (88a, 88b, 88) of each LaserEMAT (82a, 82b, 82), caused by Discontinuities (2) in the Local Active Fraction (44a, 44b, 44) of the Inspected Material (3) in front of each LaserEMAT (82a, 82b, 82), and from there digitally deduce and generate the Frontal Topology of Defects (DTa, DTb, DT) in this Local Active Fraction (44a, 44b, 44).The MDANs are also configured to digitally combine the Frontal Defect Topology (DTa, DTb, DT), and digitally generate a three-dimensional Dynamic 3D Mapping (3DM) physically observed by the MLEMAT (89) of the interior of the cast strand of the Steel Plate (105), in the Frontal Zone (110) in front of the Inspection Ring (100) in the Structure Section (92) of the Frame Plane (95), based on the combination and digital analysis of the combined signals of the multiple Secondary Ultrasonic Electrical Signals (88a, 88b, 88). As shown in Figure 10, the Cooling Means (58) generate a Cooling Flow (59) of a Heat Transfer Fluid (60), pushed under pressure inside ML / a / zuz j / uuz 11 ¡ of each Track Hole (41, 57) of the Slotted Cylindrical Aperture (39) of each Perforated Matrix Laminated Magnetic Core (22) of each adjacent EMAT (1) of the MLEMAT (89); this at a markedly lower Cooling Temperature (TF) (by at least 50° C) than the Curie Temperature (TC) of the Magnetic Material of the High Frequency Apertured Active Laminates (29). It is understood that thanks to this MLEMAT (89), the DSR Action Parameters (PASD) of the Dynamic Soft Reduction Device (DSRD) can be dynamically adjusted optimally, based on a Dynamic 3D Mapping (3 DM) of the molten strand of the Steel Plate (105) physically observed by the MLEMAT (89), this at a Melting Temperature (TS) greater than 1000°C. Referring to Figure 12, a variant of the Multi-Laser-EMAT (MLEMAT) 3D scanner (89) is shown for the automatic adjustment of the dynamic parameters of Dynamic Soft Reduction (DSR) which also allows the configuration of the Dynamic Secondary Cooling (DSC) of the molten strand of a Steel Plate (105) continuously melted into filaments in a steel mill at a Melting Temperature (TS) above 1000° C.The MLMAT (89) is coupled to a Dynamic Secondary Cooling Device (DSCD) which further comprises a computerized DSC Optimization System (DSCM), which generates Dynamic DSC Optimization Parameters (PCSC) of the Dynamic Secondary Cooling (DSC) based on the physically observed 3D Dynamic Mapping (3DM) of the molten strand of the Steel Plate (105), in the Structure Section (92) of the Frame Plane (95), by combining and digitally analyzing the combined signals of the multiple Secondary Ultrasonic Electrical Signals (88a, 88b, 88) in each Laser-EMAT (82a, 82b, 82) of the MLMAT (89), and on the casting parameters. It also includes a Digital DSC Activator (ASC), dynamically adjusting the DSC Action Parameters (PASC) of the Dynamic Secondary Cooling (DSC) water flow, based on the PCSC generated by the DSCM, this based on the 3D Dynamic Mapping (3DM) physically observed by the MLEMAT (89). The MLEMAT (89) for automatic adjustment of the DSR and / or DSC of the invention provides a technical solution to the aforementioned technical problem (d). It ensures the automatic adjustment of the DSR Action Parameters (PASD) of Dynamic Soft Reduction (DSR) and / or the DSC Action Parameters (PASC) of Dynamic Secondary Cooling (DSC) of a continuous strand casting of steel plates (105) in a steel mill, based on the observed state of the interior of the molten strand of the steel plate (105). It continuously provides an observed Dynamic 3D Mapping (3DM) of the interior of the molten strand of the steel plate (105). It continuously defines, in 3D mode and in an observed manner, the location of the Central Soft Zone (106) of the molten strand of a cast steel plate (105) and its segregation defects, based on a 3D physical observation, and not simply provided by a numerical simulation prediction by a theoretical algorithm based on a mathematical model.It accurately detects the observed position of the reduction point of the molten strand of a steel plate (105), based on a 3D physical observation. It improves the accuracy and reliability of the automatic adjustment of the parameters of Dynamic Soft Reduction (DSR) and Dynamic Secondary Cooling (DSC) of continuously molten strands of Steel Plates (105) at temperatures above 1000°C. It enables the reduction of segregation defects and porosity in the Central Soft Zone (106) of the molten strand structure of Steel Plates (105) during the continuous strand casting process in a steel mill. ADVANTAGEOUS EFFECTS OF THE INVENTION The MLEMAT (89) for DSR and DSC of the invention offers valuable industrial advantages in the non-destructive automated control of hot-melted strands of steel plates in the steel industry: a. It can operate at a melting temperature in molten steel plate strands that can exceed 1200 °C. b. It can perform continuous 3D mapping of molten steel plate strands at a speed of up to 1 meter per second. c. It allows direct transition between steel strand casting and steel rolling, without the need to cool the steel plates to a maximum of 100°C to proceed with NDT using common instruments. d. Saves the gas commonly used to reheat steel plates to 1200°C after NDT and before rolling the steel. e. It provides a continuously observed 3D mapping from molten strands of steel plates, to automatically and dynamically adjust the parameters of the continuous filament casting equipment. f. Continuously identifies, with high definition and reliability, all types of discontinuities (internal and on the surface) in cast strands of Steel Plates, as well as their coordinates. g. It improves standardization, quality control and accuracy of quality grading of the steel plates produced and increases the added value of continuous filament casting. h. Provides precise real-time automatic adjustment of dynamic parameters for the DSR and / or DSC of a continuous filament casting of Steel Plates. i. It provides early detection of discontinuities in steel plates, and automatically allows their possible orientation towards the preceding production processes based on their quality, inducing considerable savings in time, energy, materials and labor. j. Increases the performance and productivity of a steel casting machine by 7% or more. k. It can be installed without significant structural changes to the existing foundry equipment of a steel mill because it is compact. INDUSTRIAL APPLICATION OF THE INVENTION The invention has industrial applications in the metallurgical industry, and particularly in the steel industry, for quality testing and automatic adjustment of DSR and / or DSC of hot strands of steel plates at over 1000°C in continuous steel filament casting lines, and for quality control of semi-finished products in the metallurgical industry. The invention also has industrial applications in the railway industry, for high-speed control of railway rails and the control of mounted wheel sets. Furthermore, the invention has industrial applications in the oil and gas, chemical, and nuclear industries, for online testing of pipelines, drilling devices, and equipment in hazardous and / or high-temperature environments. Although only certain features of the invention have been illustrated and described in this document, those skilled in the art will appreciate numerous modifications and changes. It should therefore be understood that the appended claims are intended to cover all such modifications and changes that fall within the true spirit of the invention.

Claims

1. An electromagnetic acoustic transducer (EMAT) (1) for detecting surface and internal discontinuities (2) in an electrically conductive inspected material (3), comprising: a. At least one magnet (4) or electromagnet, configured to generate a static or quasi-static magnetic field (SMF) in the inspected material (3); b. At least one high-frequency electric coil (6), the latter being of type i.or, configured as a High Frequency Electromagnetic Transmitter (9) of an Emitted High Frequency Electromagnetic Field (HFEMF), if the EMAT (1) is used in Emission Mode (EM), and then connected to the output of at least one AC Source Current (11), driving a high frequency alternating current (AC) in the high frequency electric coil (6) at ultrasonic frequency, • inducing the emitted high frequency electromagnetic field (HFEMF) in the direction of the inspected material (3), • producing material eddy currents (14) on the surface of the inspected material (3), • generating Lorentz Forces (15) at ultrasonic frequency in the Inspected Material (3), by the interaction of the Material's (14) eddy currents with the Static Magnetic Field (SMF) and / or a Magnetostriction, • whose disturbance generates Primary Ultrasonic Waves (17) directly in the Inspected Material (3); ii.and / or, configured as a High Frequency Electromagnetic Receiver (18), if the EMAT (1) is used in Reception Mode (RM), and is then traversed by a Secondary Ultrasonic Electrical Signal (88) at ultrasonic frequency, • generated by an emitted high frequency electromagnetic field (HFEMF), • Induced by the Material's Eddy Currents (14) produced on the Inspected Surface (8) of the Inspected Material (3) by Secondary Ultrasonic Waves (21), under the influence of an ultrasonic source, interacting with the Static Magnetic Field (SMF), and which are representative of the surface and internal discontinuities (2) of the Inspected Material (3); c. At least one Perforated Matrix Laminated Magnetic Core (22), configured to concentrate and direct the Emitted High Frequency Electromagnetic Field (HFEMF) in the direction of or from the Inspected Material (3); of the type comprising a sandwich matrix (23), i.consisting of a multitude of laminated Thin Sheets (24) periodically stacked along the Die Axis (25), these Thin Sheets (24) being positioned between the two main Die Faces (26) of the Sandwich Die (23), parallel to its flat Stacking (27), i. having multiple adjacent lateral edge faces (35), extending substantially perpendicular to the stacking plane (27) and perpendicular to the die axis (25); • one of them, the First Edge Face (36) of the Die (23), facing the Inspected Surface (8) of the Inspected Material (3), • and the other, the Second Edge Face (37) of the Die (23) being substantially opposite the First Edge Face (36), and facing the high-frequency Electric Coil (6); iii.each laminated Thin Sheet (24) of the Matrix (23) • having a spatial geometry and lateral dimensions similar to those of adjacent Thin Sheets (24) in the Matrix (23); and, • having two main lateral Sheet Surfaces (32), parallel to the Stacking Plane (27); iv. of which the successive combined adjacent Peripheral Edges (33) of each Thin Sheet (24) constitute a slotted Edge Surface (34) of the Matrix (23), surrounding the Matrix Axis (25); and, v. defining a Core Axis (38) of the Matrix (23), substantially joining the centers of the First Edge Face (36) and the Second Edge Face (37); positioned substantially perpendicular to the Matrix Axis (25); ινΐΛ / a zuzó / uuz 1i ( d. comprising this Sandwich Matrix (23) at least a First Multitude (28) of High Frequency Active Sheets (29) (or groups of said sheets), each of them i. being isolated from one another, ii.externally incorporating an electrically conductive material; and / or being externally coated with an electrically conductive layer on its Peripheral Edges (33), and, iii. internally incorporating a Magnetic Material of ferromagnetic or ferromagnetic type, and having a Curie Temperature (TC); This Electromagnetic Acoustic Transducer (EMAT) (1) being characterized in combination in that: a. It comprises a Slotted Cylindrical Opening (39), i. passing through each Thin Sheet (24) of the Matrix (23), along an Opening Axis (40) of the Sandwich Matrix (23), substantially parallel to the Matrix Axis (25) and perpendicular to the Core Axis (38), and, ii. opening into each of the two lateral Matrix Faces (26); b. It comprises a multitude of magnetic track holes (41), i. of similar transverse dimensions, ii.perforated through and substantially in the center of each of the multiple high-frequency active sheets (29) of the array (23), along an axis substantially parallel to the inspected surface (8), iii. having a Longitudinal Through-Hole Envelope (42), arranged along the Aperture Axis (40) of the Array (23), the lateral perimeter of which is continuously closed, and, iv. aligned to form by their alignment the Slotted Cylindrical Aperture (39); and, c. Consists of a multitude of Induced Current Closed Loops (43) which, when the EMAT (1) is in operation, are i. induced by the emitted high-frequency electromagnetic field (HFEMF), which is emitted by the high-frequency alternating current (AC) at ultrasonic frequency in the high-frequency electric coil (6) and / or emitted by the eddy currents of the material (14) at ultrasonic frequency in the inspected material (3), ινΐΛ / azuz j / uuz 1i ¡ ¡i .located within the Active Laminate Skin (48) of the periphery of each high-frequency Active Laminate (29) of the Perforated Matrix Laminated Magnetic Core (22), iii. arranged according to a Loop Mapping (LM), defining the topology and relative positions of all Induced Current Loops (43); d. Each Magnetic Path Hole (41) in each high-frequency Active Laminate (29) is located between - the First Edge Face (36) facing the Inspected Surface (8), and - the Second Edge Face (37) facing the high-frequency Electric Coil (6); e. Each Magnetic Path Hole (41) of the Slotted Cylindrical Opening (39) is internally free of any hard material, and in particular is free of any electrically conductive material passing through it; f.The Loop mapping (LM) is topologically discrete and consists of a multitude of discrete portions of Induced Current Loops (43) of the high-frequency active sheets (29), (or groups of such high-frequency active sheets) distant from each other; g. The remote Induced Current Loops (43) (or group of such Loops), i. are induced within the active sheet skin (48) at the peripheral edges (33) of the high-frequency active sheets (29), ii. each is arranged along a Loop plane parallel to the Stacking Plane (27), and substantially perpendicular to the surface of the Inspected Material (3); iii. are substantially parallel, and separated from each other, between their respective high-frequency Active Sheets (29), iv. surround the Magnetic Path Holes (41) of their high-frequency Active Sheet (29) and rotate around it; and, a.Each Core Spacing Slice (49) of the Perforated Matrix Laminated Magnetic Core (22) and its surface, located between two adjacent High Frequency Active Sheets (29) (or group), is free of Induced Current Loops (43); Such that a combined and interactive double physical effect is produced within the Perforated Matrix Laminated Magnetic Core (22): a. Each of the multiple parallel and topologically discrete Induced Current Loops (43) of each perforated high frequency active sheet (29), i. separately generates a high frequency magnetic field, ii. separately and locally increases the discrete and selective high frequency magnetic coupling between a narrow local active fraction (44) on the inspected surface (8) opposite the high frequency active sheets (29) and the high frequency electric coil (6), and, iii. participates in the mutual reduction of the high frequency magnetic reluctance of the EMAT (1); b.The Inner Perimeter (45) of each Magnetic Path Hole (41) in each High Frequency Active Sheet (29) of the Array (23), i. creates a free Heat Conductive and Convective Surface (46) within the center of its High Frequency Active Sheet (29), ii. produces an internal Thermal Cooling effect to dissipate a fraction of the local electrical and heat energy generated by the specific Induced Current Loop (43) of its specific High Frequency Active Sheet (29), and, iii. participates in the improvement of the efficiency of the EMAT (1).

2. An electromagnetic acoustic transducer (EMAT) (1) according to claim 1, wherein: a. Each high-frequency apertured active sheet (29) of the array (23) (or group of said active sheets) is separated from its neighbors, at the level of the adjacent core spacing slices (49), by at least one sheet of a second multitude (54) of Passive Sheets (53) of electrically insulating material; b. Each Passive Sheet (53) is perforated by a Swording Track Hole (57); and, c. Each Passive Sheet (53) is positioned and configured such that: i. The Magnetic Way Holes (41) in the First Multitude (28) of High Frequency Active Laminates (29) of the Array (23), as well as the Swording Ways (57) of the Second Multitude (54) of Passive Laminates (53) of the Sandwich Array (23), i.are aligned parallel to the Matrix Axis (25), to form by their alignment and combination the Slotted Cylindrical Opening (39); This Electromagnetic Acoustic Transducer (EMAT) (1) being characterized in combination in that: a. Each Swording Track Hole (57) in each Passive Sheet (53) is located between i. the First Edge Face (36) facing the Inspected Material (3), and, ii. the Second Edge Face (37) facing the high-frequency Electric Coil (6); and, b. Each Swording Track Hole (57) of its Slotted Cylindrical Opening (39), i. is internally free of any hard material, ii. and in particular is free of any electrically conductive material passing through it; So the inner periphery of each Swording Track Hole (57) in each Passive Sheet (53) of the Array (23) creates a. A Heat Conductive and Convective Surface (46) internal to the center of the Passive Sheet (53), b.which produces an internal thermal cooling effect in this Swording Track Hole (57) to dissipate a fraction of the electrical and heat energy generated by the Induced Current Loops (43) of the adjacent high-frequency Active Laminates (29), and which participates in the improvement of the efficiency of the EMAT (1).

3. An Acoustic Electromagnetic Transducer (AET) (1) according to claim 2, characterized in that, for at least one Passive Sheet (53) and preferably for all, a. The Peripheral Edges (33) of its peripheries are free of any conductive material covering its surfaces; b. Such that the slotted Edge Surface (34) of the Perforated Matrix Laminated Magnetic Core (22) is not continuously coated and / or constituted by an electrically conductive layer, but on the contrary, consists of alternating edges with edges, formed on one side by conductive rings around the high-frequency Active Sheets (29) and on the other side by insulating rings around the Passive Sheets (53).

4. An Electromagnetic Acoustic Transducer (EMAT) (1) according to claim 1, of the type further comprising: a. Cooling means (58) i. generating a Cooling Flow (59) of a Heat Transfer Fluid (60) at a Cooling Temperature (TF), i. configured so that the Cooling Flow (59) is forced to pass through the Slotted Cylindrical Opening (39) of the Die (23); This Electromagnetic Acoustic Transducer (EMAT) (1) being characterized in combination in that: a. The Cooling Flow (59) is configured i. pass successively through at least one Magnetic Track Hole (41) of the First Multitude (28) and, alternately, through at least one of the Sword Track Holes (57) of the Second Multitude (54), i. to absorb all the Hole Wall Surfaces (62) of each successive Magnetic Track Hole (41) and / or each Sword Track Hole (57) of the Array (23), iii.a. Increase the internal thermal cooling effect in each High Frequency Active Lamina (29) of the Array (23); each of them being subject to an Induced Current Loop (43) and heat dissipation; and, b. The Cooling Temperature (TF) of the Cooling Flux (59) is more than 50°C lower than the Curie Temperature (TC) specific to the Magnetic Material of each opened High Frequency Active Lamina (29).

5. An Electromagnetic Acoustic Transducer (EMAT) (1) according to claim 4, characterized in that, in combination: a. At least one (and preferably a multitude of) Thin Sheet(s) (24) of the Perforated Matrix Laminated Magnetic Core (22) i. - either pierced by a Damping Hole (63), - or provided with a Damping Notch (64), passing through the Annular Wall (65) formed between its Track Hole (41, 57), and the portion of its First Edge Face (36) facing the Inspected Material (3), in a direction parallel to the Stacking Plane (27), ii. to create a Damping Recess (66) between the Track Holes (41, 57) of the Thin Sheet (24) and the First Edge Face (36) opposite the Inspected Material (3); and, b. The cooling means (58) are configured to i. extract a Damping Fluid Flow (67) from the Cooling Flow (59) flowing through the Track Holes (41,57), i.flow under pressure this Damping Fluid Flow (67) extracted through the Damping Recess (66), ML / a / ZUZ J / UUZ I í ! iii. create a Lifting Air Damper (70) between the Perforated Matrix Laminated Magnetic Core (22) and the Inspected Material (3), at the level of the Damping Recess (66) opposite the Inspected Material (3), and vi. thereby lifting the Perforated Matrix Laminated Magnetic Core (22) above the Inspected Material (3) from a Damping Space (68).

6. An Electromagnetic Acoustic Transducer (EMAT) (1) according to claim 1, characterized in that, in combination: a. The two outer Sheet Surfaces (32) of the two outer Thin Sheets located on the Matrix Faces (26) are constituted or covered by a Conductive Coating Layer (69) of an electrically conductive material; b. A Track Hole with transverse dimensions similar to those of the Magnetic Track Holes (41) is perforated through each of the two Conductive Coating Layers (69); c. The multiple Thin Sheets (24) and the two Conductive Coating Layers (69) of the Matrix (23) are positioned relative to each other such that their multiple Track Holes are aligned to form, by continuity, the Slotted Cylindrical Opening (39).

7. An Electromagnetic Acoustic Transducer (EMAT) (1) according to claim 1, characterized in that: a. The perimeter of each Magnetic Path Hole (41) in each High Frequency Active Sheet (29) is rectangular.

8. An Electromagnetic Acoustic Transducer (EMAT) (1) according to claim 7, characterized in that, in combination: a. The center of each Magnetic Path Hole (41) is substantially located at the center of gravity of its high-frequency Active Sheet (29); and, b. The perimeter of the hole of each Magnetic Path Hole (41) is positioned substantially at a constant Ring Distance (Rd) from the perimeter of its high-frequency Active Sheet (29); c. Such that each high-frequency Active Sheet (29) is topologically configured as a rectangular Active Ring (71), thermodynamically cooled from the heating of the Induced Current Loop (43) generated around it.

9. An Electromagnetic Acoustic Transducer (EMAT) (1) according to claim 1, characterized in that: a. The Second Edge Face (37) of the Perforated Matrix Laminated Magnetic Core (22) faces directly towards the high-frequency Electric Coil (6), and, b. No magnet is placed between - on the one hand, the Second Edge Face (37) of the Matrix (23) and - on the other hand, the high-frequency Electric Coil (6).

10. An Electromagnetic Acoustic Transducer (EMAT) (1) according to claim 1, characterized in that: a. the orientation, pitch, size and shape of each of the Circuit-Facing Edges (72) of each High-Frequency Active Sheet (29), located on the Second Edge Face (37) of the Matrix (23), and facing the High-Frequency Electric Coil (6); b. are consistent and correlated with the geometric parameters, including the orientation, pitch, size and shape, of the Conductive Fractions (75) of the High-Frequency Electric Coil (6) successively facing each of these Circuit-Facing Edges (72).

11. An electromagnetic acoustic transducer (EMAT) (1) according to claim 10, wherein: a. The high-frequency electric coil (6) has at least a linear conductive fraction (73); and, b. This linear conductive fraction (73) is positioned in close proximity to and directly over a circuit-facing edge (72), and is tangent along an axis parallel to this portion near the perimeter of a high-frequency active sheet (29) located on the face of the second edge (37) of the array (23) opposite the high-frequency electric coil (6); This Electromagnetic Acoustic Transducer (EMAT) (1) being characterized in combination by the fact that the Linear Conductive Fraction (73) and the Perforated Matrix Laminated Magnetic Core (22) are configured in such a way that, when the EMAT (1) is in operation, an induced current loop (43) ινΐΛ / a zuz j / uuz 1i ¡ d.is induced in the Active Sheet Skin (48) at the periphery of the high-frequency Active Sheet (29), e. surrounds its Magnetic Path Hole (41), f. so that this makes a local selective high-frequency magnetic coupling between: i. a high-frequency alternating current (AC) driven in the linear conductive fraction (73) that extends over and along the periphery of the high-frequency active sheet (29), and ii. the Material Eddy Currents (14) generated in the Local Active Fraction (44) of the Inspected Surface (8) opposite the high-frequency Active Sheet (29).

12. An electromagnetic acoustic transducer (EMAT) (1) according to claim 11, wherein: a. The high-frequency electrical coil (6) is of the type having a multitude of (at least two) parallel and adjacent linear conductive fractions (73) as a meander circuit (74); b. This multiple of parallel fractions of the linear conductive (73) is positioned successively in proximity to, and directly above, a circuit-facing edge (72) of a high-frequency active sheet (29), located on the second edge face (37) of the array (23) opposite the high-frequency electrical coil (6), and configured such that the high-frequency alternating current (AC) flowing successively from the parallel and neighboring fractions of the linear conductive (73) is oriented in opposite alternating directions; c.at least one high-frequency Magnetic Flux Loop of the conductive material (76) substantially surrounds each Fraction of the Linear Conductive Material (73) perpendicularly, and substantially penetrates perpendicularly into the High-Frequency Active Sheet (29) opposite it; This Electromagnetic Acoustic Transducer (EMAT) (1) is characterized in that the Fractions of the Linear Conductive Material (73) of the high-frequency Electric Coil (6) and the Perforated Matrix Laminated Magnetic Core (22) are configured such that when the EMAT (1) is in emission (EM) mode: a. Two adjacent high-frequency active sheets (29), capped by two adjacent fractions of the linear conductive material (73), b.They are traversed in their Active Sheet Skin (48) by two adjacent Induced Current Loops (43), each composed of a high frequency alternating electric current that rotates in an opposite Rotation Direction (78), around the Aperture Axis (40) that passes through their Magnetic Track Holes (41), one clockwise, while the other is counterclockwise.

13. An Electromagnetic Acoustic Transducer (EMAT) (1) according to claim 1, characterized in that, in combination: a. The Opening Depth (Od) of the Slotted Cylindrical Opening (39) of its Perforated Matrix Laminated Magnetic Core (22), along its Opening Axis (40), b. is substantially equal and consistent with a First Transverse Dimension (FTd) of at least one High Frequency Electric Coil (6) of the EMAT (1).

14. An Electromagnetic Acoustic Transducer (EMAT) (1) according to claim 1, characterized in that, in combination: a. the Slotted Face of the Second Edge (37) of its Perforated Matrix Laminated Magnetic Core (22), facing a high-frequency Electric Coil (6), b. has a transverse dimension, in a direction perpendicular to the Aperture Axis (40) of the Matrix (23), which is substantially equal to and consistent with a Second Transverse Dimension (STd) of at least one high-frequency Electric Coil (6) of the EMAT (1).

15. An Electromagnetic Acoustic Transducer (EMAT) (1) according to claim 1, characterized in that, in combination, the Geometric Dimensions of the Perforated Thin Sheet (24) of its Perforated Matrix Laminated Magnetic Core (22) and / or the combined geometric dimensions of its perforated matrix laminated magnetic core (22) are selected to: a. Be uncorrelated from the wavelengths of the main harmonics of the emitted high-frequency electromagnetic field (HFEMF), and b. Avoid mechanical resonance of its Perforated Matrix Laminated Magnetic Core (22) at the ultrasonic operating frequency of the EMAT (1).

16. An Electromagnetic Acoustic Transducer (EMAT) (1) according to claim 1, characterized in that, in combination, the Geometric Dimensions of the perforated Thin Sheets (24) of its Perforated Matrix Laminated Magnetic Core (22) are, at the ultrasonic operating frequency of the EMAT (1): ινΐΛ / a zuzj / uuz 1i( a. Or, smaller than the wavelengths of the ultrasonic waves generated in these Thin Sheets (24), b. Or substantially equal to an odd number of quarters of the wavelengths of the ultrasonic waves generated in these Thin Sheets (24).

17. An electromagnetic acoustic transducer (EMAT) (1) according to claim 1, of the type wherein the face of the first slotted edge (36) of the perforated matrix laminated magnetic core (22) faces the inspected material (3) and parallel to the slotted cylindrical opening (39) is covered porously with an insulating layer (81) made of an electrically insulating material; this EMAT (1) being characterized in that further one of the sides of the Insulating Layer (81) a. Is disposed opposite the Slotted Cylindrical Opening (39), and, b. Covers, on the edge belonging to the Face of the First Edge (36), the perimeter of each of the perforated high-frequency Active Sheets (29).

18. A Laser-EMAT Probe (LEMAT) (82), for inspecting a conductive Inspected Material (3), by receiving an ultrasonic signal from this Inspected Material (3), comprising the combination of: a. An electromagnetic acoustic transducer (EMAT) (1) according to any of claims 1 to 17, i. configured in Receive Mode (RM), to receive an ultrasonic signal from the Inspected Material (3), i. whose High Frequency Electric Coil (6) is configured as a High Frequency Electromagnetic Receiver (18), • induced by a High Frequency Emitted Electromagnetic Field (HFEMF) emitted by the inspected material (3), • generated by the Material's Eddy Currents (14), produced in the Inspected Material (3) by Secondary Ultrasonic Waves (21), representative of the surface and / or internal Discontinuities (2) of the Inspected Material (3), and, iii.The Perforated Matrix Laminated Magnetic Core (22) of which is located between the high-frequency Electric Coil (6) of the EMAT (1) and the local surface of the Inspected Material (3), and, • directly faces the high-frequency Electric Coil (6); b. A laser source (84) configured to: i. draw a high-energy Laser Beam (85) at a Firing Point (86) on the surface of the Inspected Material (3), i. generate ultrasonic waves that produce Primary Ultrasonic Waves (17) that propagate on the surface and / or inside the Inspected Material (3), and, i. causing the generation of Secondary Ultrasonic Waves (21) resulting from the echoes of the interactions of the Primary Ultrasonic Waves (17) with the Discontinuities (2) on and / or within the Inspected Material (3), propagating on the surface and / or within the Inspected Material (3), iv.causing the generation of Material Eddy Currents (14) on the surface of the Inspected Material (3), induced by the mechanical vibrations of the Secondary Ultrasonic Waves (21) under the influence of the Static Magnetic Field (SMF) emitted by the Magnet (4) of the EMAT (1), and, v. causing the induction of a High Frequency Emitted Electromagnetic Field (HFEMF) emitted by the Material Eddy Currents (14) present on the surface of the Inspected Material (3), representative of the geometry and position on the surface and internal Discontinuities (2) of the Inspected Material (3); This Laser-EMAT Probe (LEMAT) (82) is characterized in that: a. A multitude of parallel and remote induced current loops (43), i.are induced by the emitted high-frequency electromagnetic field (HFEMF) emitted by the eddy currents of the material (14) at the ultrasonic frequency of the inspected material (3) under the influence of the laser source (84), ii. within the Active Sheet Skin (48) at the Peripheral Edges (33) of each high-frequency Active Sheet (29) of the Perforated Matrix Laminated Magnetic Core (22); b. These Induced Current Loops (43) of each high-frequency Active Sheet (29) i. are separated from each other, ML / a / ZUZÓ / UUZ I í ! ¡i. each is arranged along a Loop Plane parallel to the Stacking Plane (27), and substantially perpendicular to the surface of the Inspected Material (3); iii. surround and rotate around the Magnetic Path Holes (41) of their high-frequency Active Sheet (29); iv.are located between the face of the first edge (36) facing the inspected material (3) and the face of the second edge (37) facing the high-frequency electric coil (6), and v. are positioned substantially perpendicular to the two Edge Faces (36, 37); Such that a combined and interactive double physical effect is produced within the Perforated Matrix Laminated Magnetic Core (22): a. Each of the multiple parallel and topologically discrete induced current loops (43) of each high-frequency active sheet (29), i. separately generates a high-frequency magnetic field, ii. separately, locally and discretely, increases the high-frequency magnetic coupling between - a narrow Local Active Fraction (44) of the Inspected Surface (8) facing its high-frequency Active Sheet (29), and - the high-frequency Electric Coil (6), and, iii.homogenizes the high-frequency coupling, and participates by mutualization in the overall reduction of high-frequency magnetic reluctance, and in the increase of the resolution of the EMAT (1); b. The Inner Perimeter (45) of each Magnetic Path Hole (41) in each high-frequency Active Sheet (29) of the Array (23), i. creates an internal surface free of heat conduction and convection (46) at the center of its high-frequency active sheet (29), and, iii. produces an internal Thermal Cooling effect to dissipate a fraction of the local electrical and heat energy generated by the Induced Current Loop (43) of its specific high-frequency Active Sheet (29), and, iii. participates in the improvement of the efficiency of the EMAT (1).

19. A 3D Multi-Laser-EMAT (MLEMAT) scanner (89), for detecting surface and / or internal discontinuities (2) within a movable cylindrical conductive structure (90), comprising the combination of: a. A conductive structure (90) to be 3D scanned, i. made of an electrically conductive inspected material (3), ii. having a cylindrical structure generated along a structure axis (91), i. having a substantially constant structure section (92); b. A chassis frame (93), i. configured to surround the conductive structure (90) at a frame distance (Fd), i. whose frame plane (95) is substantially perpendicular to the structure axis (91) of the conductive structure (90); c. A Probe Multitude (96) comprising at least two Laser-EMAT (LEMAT) probes (82) according to claim 18, wherein each of the Laser-EMAT (LEMAT) probes (82) is i. fixed to the Chassis Frame (93), and, ii.positioned and configured in such a position that each of the Faces of the First Edge (36) of its Perforated Matrix Laminated Magnetic Core (22) faces the Conductive Structure (90); d. Displacement means (97) configured to linearly move i. the cylindrical Conductive Structure (90) relative to the Chassis Frame (93), ii. along a Displacement Direction (Md), substantially coincident with the Structure Axis (91); This Multi-Laser-EMAT 3D scanner (MLEMAT) (89) is characterized in that: a. The Loop of apertures (99), i. constituted by the virtual line joining the centers of each successive Slotted Cylindrical Opening (39) of the Perforated Matrix Laminated Magnetic Core (22) of each adjacent EMAT (1) of the Laser-EMAT Probes (LEMAT) (82) of the MLEMAT (89), ii. surrounds the Conductive Structure (90).

20. A Multi-Laser-EMAT (MLEMAT) 3D Scanner (89) according to claim 19, characterized in that its Probe Multitude (96) composed of Laser-EMAT (LEMAT) Probes (82) are attached to the Chassis Frame (93), positioned and configured in such a position that: a. The juxtaposition of the multitude of adjacent first-edge faces (36) neighboring the perforated matrix laminated magnetic cores (22) of its adjacent Laser-EMAT (LEMAT) probes (82), facing the inspected material (3), are substantially contiguous with each other; and, b. It constitutes a substantially continuous grooved Inspection Ring (100), which surrounds and covers the perimeter of the Conductive Structure (90), in a Structure Section (92) of the Conductive Structure (90) near the Frame Plane (95).

21. A Multi-Laser-EMAT (MLEMAT) 3D scanner (89) according to claim 19, of the type wherein a. The Laser Source (84) of each LEMAT (82) consists of an Optical Fiber (101), fixed to the Frame Plane (95), having a Firing End (102) facing the Conductive Structure (90); and, b. Each Optical Fiber (101) is connected to a Laser Generator (103); This Multi-Laser-EMAT (MLEMAT) 3D scanner (89) is characterized in that the Laser Firing Loop (104), a. constituted by the virtual line joining the Firing Ends (102) of each adjacent Laser-EMAT (LEMAT) Probe (82) of the MLEMAT (89), b. surrounds the Conductive Structure (90) and is substantially parallel to the Loop of Openings (99).

22. A Multi-Laser-EMAT 3D scanner (MLEMAT) (89) according to claim 19, for detecting surface and / or internal discontinuities (2) of a metallurgical plate (105), wherein: a. The conductive structure (90) is a cylindrical metallurgical plate (105) that is movable with respect to the MLEMAT (89); This Multi-Laser-EMAT 3D scanner (MLEMAT) (89) is characterized in that: a. The Aperture Loop (99), formed by the virtual line joining the centers of each successive Slotted Cylindrical Aperture (39) of the Perforated Matrix Laminated Magnetic Core (22) of each adjacent EMAT (1) of the Laser-EMAT Probes (LEMAT) (82) of the MLEMAT (89), surrounds the movable cylindrical Metallurgical Plate (105). ινΐΛ / a zuz j / uuz 1i ¡ 23. A 3D Multi-Laser-EMAT (MLEMAT) scanner (89) according to claim 22, for detecting surface and / or internal discontinuities (2) of a steel plate (105), of the type in which: a. The conductive structure (90) is a movable cylindrical strand cast from steel plate (105); continuously cast in a steelworks at a melting temperature (TS) above 1000° C, and, b.The high-frequency apertured active laminations (29) of each perforated matrix laminated magnetic core (22) of each adjacent EMAT (1) of the MLEMAT (89) are made of a magnetic material, for example, of the ferromagnetic or ferromagnetic type, having a Curie temperature (TC) lower than the melting temperature (TS); This 3D Multi-Laser-EMAT (MLEMAT) scanner (89) is characterized in combination in that each slotted cylindrical aperture (39) of each perforated matrix laminated magnetic core (22) of each adjacent EMAT (1) of the MLEMAT (89) is connected to cooling media (58) generating a cooling flow (59) of a heat transfer fluid (60), a. pushed under pressure into each track hole (41, 57) of the slotted cylindrical opening (39) of each perforated matrix laminated magnetic core (22) of each adjacent EMAT (1) of the MLEMAT (89); b.at a Cooling Temperature (TF) more than 50°C lower than the Curie Temperature (TC) of the Magnetic Material of the high frequency Active Sheets opened (29).

24. A 3D Multi-Laser-EMAT (MLEMAT) scanner (89) according to claim 23, for the automatic adjustment of the dynamic parameters of the Dynamic Soft Reduction (DSR) of the molten strand of a Steel Plate (105) in continuous casting in a steel mill at a Melting Temperature (TS) above 1000° C, of ​​the type in which: a. The molten strand of the steel plate (105) is continuously pushed through a dynamic soft reduction device (DSRD), to suppress the formation of a macro-segregation zone and porosity zones within the molten strand of the steel plate (105), thereby dynamically compensating for the solidification shrinkage of the steel and for the interruption of the suction flow of the residual molten metal in the Central Soft Zone (106); b. The MLMAT (89) is coupled to this dynamic soft reduction device (DSRD) comprising: i.A Dynamic 3D Mapping System (3DMS), generating a Dynamic 3D Mapping (3DM) of the cast strand of the Steel Plate (105), ινΐΛ / a zuz j / uuz 1i¡ ¡i. A computerized DSR Optimization System (DSRM), generating Dynamic DSR Optimization Parameters (PCSD), based on the Dynamic 3D Mapping (3DM) and on the strand filament casting parameters, and, c. A Digital DSR Activator (ASR), dynamically adjusting the DSR Action Parameters (PASD) of the Dynamic Soft Reduction Device (DSRD), based on the PCSD generated by the DSRM; This Multi-Laser-EMAT 3D scanner (MLEMAT) (89) is characterized in combination in that: a.The high-frequency electrical coils (6a, 6b, 6) of each EMAT (1a, 1b, 1) of each Laser-EMAT (82a, 82b, 82) of the MLEMAT (89) are each connected to the 3D Dynamic Mapping System (3DMS), and transmit to it a Secondary Ultrasonic Electrical Signal (88a, 88b, 88) induced in each high-frequency electrical coil (6a, 6b, 6) by the eddy currents of the material (14) in the front zone (110) of the inspected material (3) of the steel plate (105) locally in front of each EMAT (1a, 1b, 1); b. The DSR optimization system (DSRM) is provided with analog and digital processing means (MDAN) configured for i. Receiving the multitude of Secondary Ultrasonic Electrical Signals (88a, 88b, 88) included in the Secondary Ultrasonic Electrical Currents (19a, 19b, 19) passing through each High Frequency Electrical Coil (6a, 6b, 6) in each LaserEMAT (82a, 82b, 82) of the MLEMAT (89), e, ii.Identify the changes and disturbances in each Secondary Ultrasonic Electrical Signal (88a, 88b, 88) of each Laser-EMAT (82a, 82b, 82), caused by the Discontinuities (2) in the Local Active Fraction (44a, 44b, 44) of the Inspected Material (3) in front of each Laser-EMAT (82a, 82b, 82), and from there digitally deduce and generate the Frontal Topology of Defects (DTa, DTb, DT) in this Local Active Fraction (44a, 44b, 44), and, iii. Digitally combine the Frontal Defect Topology (DTa, DTb, DT), and digitally generate a three-dimensional Dynamic 3D Mapping (3DM) physically observed by the MLEMAT (89) of the interior of the molten strand of a Steel Plate (105), in the Frontal Zone (110) in front of the Inspection Ring (100) in the Structure Section (92) of the Frame Plane (95), based on the combination and digital analysis of combined signals from the multiple Secondary Ultrasonic Electrical Signals (88a, 88b, 88); and, ινΐΛ / azuzj / uuz 1i ¡ c.The Cooling Media (58) generate a Cooling Flow (59) of a Heat Transfer Fluid (60), i. thrust under pressure within each Way Hole (41, 57) of the Slotted Cylindrical Aperture (39) of each Perforated Matrix Laminated Magnetic Core (22) of each adjacent EMAT (1a, 1b, 1) of the MLEMAT (89); ii. at a Cooling Temperature (TF) markedly lower (by at least 50°C) than the Curie Temperature (TC) of the High Frequency Active Sheet Magnetic Material (29); d. In order for the DSR Action Parameters (PASD) of the Dynamic Soft Reduction Device (DSRD) to be dynamically and automatically adjusted optimally, based on a Dynamic 3D Mapping (3DM) of the molten strand of a Steel Plate (105) physically observed by the MLEMAT (89), this at a Melting Temperature (TS) greater than 1000° C.25 A 3D Multi-Laser-EMAT (MLEMAT) scanner (89) according to claim 24, for the automatic adjustment of the dynamic parameters of Dynamic Soft Reduction (DSR) which also allows the configuration of Dynamic Secondary Cooling (DSC) of the molten strand of Steel Plates (105) continuously melted in filaments in a steel mill at a Melting Temperature (TS) above 1000°C, characterized in that the MLEMAT (89) is coupled to a Dynamic Secondary Cooling Device (DSCD) which further comprises: a. A computerized DSC Optimization System (DSCM), which generates Dynamic DSC Optimization Parameters (PCSC) based on i.in the physically observed Dynamic 3D Mapping (3DM) of the molten strand of a Steel Plate (105), in the Structure Section (92) of the Frame Plane (95), by combining and digitally analyzing the combined signals of the multiple Secondary Ultrasonic Electrical Signals (88a, 88b, 88) in each Laser-EMAT (82a, 82b, 82) of the MLEMAT (89), ii. and on the casting parameters; b. A digital DSC activator (ASC), which dynamically adjusts the DSC action parameters (PASC) of the dynamic secondary cooling (DSC) of the water flow of the dynamic secondary cooling (DSC), according to the PCSC generated by the DSC optimization system (DSCM), this based on the Dynamic 3D Mapping (3DM) physically observed by the MLEMAT (89).

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