RU2049328C1 - Process of electro-magneto-acoustic nondestructive test of article - Google Patents

Abstract

FIELD: nondestructive testing of materials. SUBSTANCE: article is subjected to method of plasma technology and metallurgy simultaneously with test for which articles is heated in zone of test to temperature of melt. Apart from this while inspecting quality of monocrystal in process of its production and test zone of test and heating is moved along article in direction from workstock of monocrystal with rate of growth of monocrystal. Zone of test of article activity interacts with plasma and electromagnetic field passed through it in process of test and testing devices work as traps and plasma filters. With movement of heated test zone along tested article quality of article increases due to concentration of impurities in test zone with heating and melt. Depth of extraction of impurities depends on dimensions of heated and melted zone of test of article. All defects and impurities with melting and recrystallization move into zone of melt and test and are removed together with portion of articles. Process enables ultra-pure materials and articles of any needed purity and shape including parts from monocrystals and composits from layers of monocrystals and articles with properties of butal to be manufactured from parts produced by powder metallurgy under conditions of Earth's attraction. Metals and semiconductors of any purity are manufactured in the process and laminar alloys are produced from ordinary materials with the aid of multiple test and clearing. EFFECT: increased qualty of article in process of its test at high temperatures. 2 cl, 1 dwg

Description

 The invention relates to methods for non-destructive testing of product quality in plasma metallurgy and technology (spraying, surfacing, film deposition, plasma cleaning, etc.), and in particular to combined control methods, during the implementation of which not only quality is determined, but also improved quality controlled products at high temperatures.

 A known method of EMA quality control of sintered products, for example, powder metallurgy products, which consists in magnetizing the product with a constant field, excitation of acoustic waves by an electromagnetic-acoustic transducer at different frequencies and recording the frequency of the first resonance, characterized in that in order to improve the accuracy of quality control of sintered products, they change the excitation frequency of the electromagnetic-acoustic transducer, determine the frequency values of two adjacent resonances and the difference between these frequencies limit the defectiveness of the product.

 The disadvantage of this control method is the inability to affect the purity of the material in the control process.

 There are methods for refining material of products, for example, electrolytic, which improve the quality of the material (for example, copper), but do not allow judging the quality of the improvement of the product; for this, additional control methods and control devices that implement them are used.

It is also known plasma refining, which consists in local overheating of the material by the plasma arc and moving it along the material, and all impurities are concentrated in the region of the plasma arc, and the cooling material after passing the arc becomes clean without impurities [2]
However, after such refining, it is necessary to carry out further quality control of cleaning.

A known method of acoustic control of products, where as the acoustic medium using plasma created by any known method. In this case, the plasma acts as a transducer of electromagnetic field oscillations into mechanical vibrations, and then converts the mechanical vibrations into voltage and current fluctuations [3]
The method allows you to affect the quality of only the surface layers of the product in the control process and does not provide the ability to influence the deep layers of the material and even more so on the quality of the entire product.

 The aim of the invention is to improve the quality of the product in the process of its control at high temperatures.

 This is achieved by the fact that in the method of electromagnetic-acoustic control of products, which consists in the fact that in a controlled product by introducing a constant and variable electromagnetic fields through a plasma layer, mechanical vibrations are excited, the parameters of these vibrations are measured and the quality of the controlled product, the product in the zone, is determined by the measurement results controls are heated to melt temperature.

 In addition, when controlling the quality of single crystals in the process of obtaining it, the control and heating zone is moved across the product in the direction from the single crystal preform with a single crystal growth rate.

 The essence of the method is as follows.

 Plasma is created at the surface of the product in the control zone by any known method [3] and to increase the plasma density in the control zone the product is heated to the melt temperature, thereby increasing the plasma density due to electronic and thermionic emission of charge carriers from the surface of the product and evaporation of the material, as well as increasing the mobility of material particles and impurities, due to which the latter can easily move along the volume of the molten material and reach the surface of the product, and then interact with plasma. The plasma ionization threshold is reduced by the introduction of special additives, as well as the introduction of special alloying additives that improve the quality of the product.

 The role of the emitter, transducer and receiver of oscillations in the controlled product and the waves propagating in it is played by a plasma in an alternating electromagnetic field and its charged particles (ions and electrons) oscillating in an electromagnetic field.

 The presence of plasma in the proposed control method allows you to combine product control with its simultaneous plasma cleaning. This allows the process to be carried out during its continuous course, controlling all 100% of the material obtained, to use additionally and plasma cleaning.

 The method of zone melting of metals and other materials in plasma metallurgy when moving the plasma zone along the surface of the product (or its volume) allows you to concentrate all impurities in the plasma zone, leaving behind a clean material after moving the plasma zone along the product. The final section of the product, where the process ends, is removed (cut off from the product, since it contains a high concentration of impurities). The process is controllable. Due to the speed of plasma movement along the product, the presence of impurities in the product can be controlled.

 Depending on the sign of the applied potential, during the control, the process of purification from impurities (plasma refining) or the process of saturating the object with special impurities and alloying additives by known methods of plasma metallurgy is carried out. The control is carried out by known methods [3] in this heated zone of the material, shifting the processes in time by a few fractions of seconds, and they control the composition of impurities using the applied voltage to the same electrodes. The cleaning is carried out by crucible or crucible-free, by any known method of "zone melting" [4] in the control zone. In this case, three zones are formed. The zone of the original ("dirty") material, the zone of melting and control, where control is carried out and where all impurities and defects are collected and exposure is carried out by means of control, and the third zone is purified material. Melting and control are realized not only in plasma and gas medium, but also in vacuum.

 Control is provided by the evaporation of the material, the emission and thermionic emission of electrons above the "zone melting", similar to the operation of a vacuum radio tube or incandescent lamp. Crucible and crucible free in the zone of control zone melting clean the product and, in addition, when recrystallized with the "seed" of the single crystal, the product is a single crystal. A distinctive feature of this method is that the seed and the product remain in place relative to each other, only the melting and control zone moves with the growth rate of the single crystal from the seed to the opposite end of the product.

 The movement of the control zone is carried out in three ways. Or, when the electrodes are stationary, the product is moved, then the melt zone remaining under the electrodes moves on the moving product in the direction opposite to the moving product. Or, when the product is stationary, the melt zone is moved together with the control electrodes over this zone. A combined path is also possible, then from the addition of moving the product and the control electrodes, the monitoring and cleaning performance will double.

 Thus, it is possible to control, clean and improve the quality of the product not only on solid products, fused, etc. but also when casting steels, metals, alloys, electrolytes, various melts, as well as when growing crystals from melts, solutions, or during gas epitaxy of crystals, for example, ruby rods for lasers and other crystals and semiconductors and rare and ultra-pure elements.

 Heating and melting of a narrow section of an ingot or pipe is carried out, for example, by high-frequency currents. The number of passes required to obtain a given quality of product material depends on the starting material and the distribution of impurities in it.

 Cleaning with a crucible-free zone melting is ensured by the fact that the molten zone is supported by surface tension. These methods: seed crystal, zone cleaning, crucible free zone melting and plasma cleaning, doping and epitaxial build-up and growing a single crystal is controlled using the combined proposed control method.

 The method allows the use of epitaxial crystal growth from a plasma gas medium and from a liquid solution and melt (gas and liquid epitaxy), controlling the process using a combined control. The principle of MHD used to move the product has a side effect in the control of the product with zone melting cleaning. Magnetohydrodynamic forces act on the product, especially on the molten zone, where the particles of the material have greater freedom of movement in the liquid phase than in the structure of the solid, causing intensive movement of these particles in the molten zone, their mixing and exit to the surface when mixing and moving all the deep layers of the molten zone, where all impurities that surfaced on the surface are carried away by the plasma when interacting with the plasma. The remaining impurities are evenly distributed over the volume of the molten zone and move together with the zone to the end of the product.

 By controlling the speed of drawing and the temperature of the melt, the diameter of the growing crystal can be kept almost constant, which is very important for pipes and gun barrels, long ruby rods for lasers and other devices.

 The drawing shows a General scheme of the method of combined non-destructive testing.

 Around the article 1 being subjected to control, a plasma 2 is created by any known method, for which easily ionizing substances are introduced into the surrounding product through an injector 3. The injector 3 is located in the control zone, where the measuring electrodes 4 are located for supplying and receiving electromagnetic energy and mechanical vibrations into the plasma using commercially available equipment. If necessary, alloying substances, coating materials and epitaxy of these coatings, etc., are introduced through the injector 3 simultaneously with easily ionizing additives.

 With combined control, the product 1 is divided into three zones. Zone 5 of the solid phase after cleaning (including after zone melting, coating, epitaxy of coatings, alloying, etc.), zone 6 of combined non-destructive testing (with plasma cleaning, zone melting, alloying and epitaxy of applied coatings), zone 7 solid phase before cleaning (including with the use of zone melting, etc.).

 The depth of zone 6 during zone melting during cleaning, obtaining a single crystal, etc. is determined by the requirement for the material of the product and for the very quality of the product, the size of the ingot of the product 1 and its dimensions. The depth of zone 6 during zone melting, you can perform layer-by-layer cleaning of the product to any depth in several passes by increasing the depth of zone melting and control.

 When mixing zone 6 at the end of zone 7, all impurities are concentrated at the end of this zone, which is cut off and sent for initial processing, and the clean section of the product 1, which transferred to zone 5, is used further by technology as a useful product after cleaning or as a finished product.

 The heater 8 serves to clean the product 1 not only in a moving plasma 2, but also to create a melting zone in the control zone 6 (which is integral with the product 1 due to the surface tension of the melt). Heater 8 can have a wide variety of operating principles, from flare burners to an electric arc heater and a high-frequency inductor, which are produced in series according to known schemes.

 Injector 3, electrodes 4, heater 8 (if necessary) are installed in a single unit and move together, forming a control-cleaning zone 6, which can be like in the solid phase during plasma cleaning (due to the movement of plasma 2 along the product 1 and due to the difference potentials between the electrodes 4, product 1, which produces the movement of charges in the plasma between the electrodes 4 and product 1), and in the liquid phase during zone melting and other related technologies (including the production of a single crystal upon recrystallization from polycrystal After cleaning zone melting in several stages, passages or multiple zones).

 The movement of the plasma 2 and the movement of the product 1 are carried out in any known manner, or when they are motionless, they move the zone 6.

 The method of combined non-destructive testing is as follows.

 Around the article 1 being subjected to control, a plasma 2 is created in any known manner (from the thermal dissociation of gases surrounding a hot controlled ingot to a high-frequency plasmatron and even torch burners, etc.), which can be moved, for example, on a roller table.

 Lightly ionizing additives are introduced into the surrounding product through the injector 3, along with which alloying materials, substances for coating, epitaxial build-up of the coating, as well as for etching and cleaning of the surface, can be introduced.

 An alternating voltage is applied to the electrodes 4, in which there is a constant component to create a potential difference between the plasma 2 and the product 1. Due to the plasma moving along the product and the product 1 in the plasma 2, as well as the potential difference between the product 1 and the plasma 2 created by the electrodes 4, the interaction of charges and plasma particles on the surface of the product with particles of the material of the product 1 in the control zone 6 occurs. Thus, the constant component, together with the plasma, performs the cleaning of the product according to the same principle as plasma cleaning.

 Depending on the technological process, the plasma composition can vary from neutral gases (argon, helium) to aggressive ones to effectively remove the upper layer in the environment of frionic, oxygen plasma or to restore the oxidized layer in a medium of hydrogen plasma (or molecular hydrogen), etc. plasma can vary from stage to stage in the process control and cleaning.

 For monitoring, along with the constant component, pulses are also fed to the electrodes 4, with the aid of which vibrations are introduced into the product 1 by means of plasma 2. The pulses are excited and reflected signals are received on serial equipment using known methods, for example, an ECHO-pulse method.

 In addition, with the help of pulses, intensification of the effect of plasma on the product to be inspected, or weakening of this effect when cleaning or coating, like plasma cleaning, etching, followed by coating and alloying of the material using known technologies, can be achieved. The injector 3, the electrodes 4 are installed in the control zone 6, where the heater 8 for zone melting of the control zone 6 is also installed if it is necessary to obtain clean and highly pure materials.

 Heater 8 can be of a wide variety of designs: from flare heaters and burners, electric arc heaters to high-frequency inductors. The drawing shows a high-frequency type heater 8 as the most efficient, which can heat a product placed even in a dielectric boat housing made of glass, ceramic, etc. for cleaning in a vacuum environment. A crucible case 12-13 m long is enough to be made of refractory ceramics based on boron with high dielectric properties (manufactured by the industry) with a connector along the axis for placement inside a drill pipe or gun barrel. At the same time, a rod of the same ceramics as the crucible case is inserted into the pipe or barrel.

 If such a case is evacuated to vacuum, then zone melting cleaning can be carried out not only in a gaseous medium or in a plasma, but also in a vacuum, the proposed method allows this with the same equipment.

 Similarly, silicon and germanium crucible or crucible-free zone melting clean the product and upon recrystallization with the "seed" of the single crystal, the product is a single crystal.

 In all cases of control with cleaning (including zone cleaning), zone 6 with electrodes 4, injector 3 and heater 8 (if needed) moves relative to product 1. For process efficiency and increased productivity, you can move product 1, plasma 2 and zone 6 (with all devices 4, 3, 8).

 When combined non-destructive testing, accompanied by cleaning, control and cleaning is carried out by controlling the current and voltage parameters passed through the plasma 2 using electrodes 4, if necessary, the energy of the heater 8 and its power (current and voltage), control the shape of the current and voltage fluctuations (amplitude and frequency), they are measured by the magnitude and shape of the pulses and, by controlling the quality and number of pulses and the constant component, they control the processes of plasma metallurgy and control the product ia and its material.

 Qualitatively and quantitatively control the parameters and shape of the pulses and the constant component of the electromagnetic energy introduced into the plasma and the controlled product. With a high-frequency inductor, electromagnetic energy is introduced into the plasma 2 by pulses and, creating oscillations in the plasma, they control, heat zone 6 and clean the product 1.

 After moving the control zone 6 (in the case of all types of cleaning), three zones are observed. The cleaned zone 5 in the solid phase (even after zone melting), zone 6 of the combined control (in zone melting it is in the liquid phase under the influence of heater 8), the contamination zone or zone 7 of impurities in the solid phase (before zone melting), at the end of which after zone melting all impurities are concentrated and which is cut off after cleaning.

 In the case of obtaining a product from a single crystal after repeated purifications by zone melting, a seed crystal is attached to the front end of the product 1 and, moving the melting zone along the product, recrystallization from a polycrystal to a single crystal is performed.

 The process control and control are similar to those described above for plasma cleaning of products and cleaning with zone melting.

 In the case of a high-frequency heater 8, all processes of heating, control and recrystallization are carried out by quantitative and qualitative control of the parameters and shape of the pulses and the constant component of the inductor 8. This also is the difference between the combined control and the known methods of refining and recrystallization. In all known methods for producing single crystals, the seed, introduced into the melt zone, is moved relative to the product with the growth rate of the single crystal. In the proposed method, both the seed and the product undergoing recrystallization remain in place relative to each other (although they can move in space together with the ceramic crucible case), only the melting zone moves with the growth rate of the single crystal from the seed to the opposite end of the product.

 This technology, while also using powder metallurgy, makes it possible to recover ultrapure metals and alloys from the powders of iron oxides and other metals and alloys and their sintered semi-finished products by zone melting in a medium of hydrogen, carbon and other gases and their plasma, and even obtain investment casting in crucibles of all sizes finished products from powder, and, if necessary, parts from single crystals in several passes by zone melting, and then recrystallization with a single crystal nucleus and obtaining the part m wootz single crystal, while receive recrystallization layered polycrystal with layers of single crystal (with the properties of Damascus steel) or even get layered alloys of simple materials and alloys with layers of varying thickness.

 All control is carried out through the characteristics of the introduced electromagnetic energy and when exposed to the product through the plasma. Change in the force parameters of the impact on the product (speed and temperature of heating, the speed of the cleaning zone, plasma generation and its parameters, etc.) and the speed of movement of the control zone 6 and the input energy acting on it through the plasma, including through pulsed action and a constant component of the voltage, leads to a change in the rate of recrystallization and is associated with the growth rate of a single crystal (during zone melting).

 In laboratory experiments, various flaw detector units UD10-UA and UD2-12, DUK-66 in various combinations were used as flaw detection equipment. Most often, generator and amplifier blocks of these devices with a block design were used.

 Using this control method allows you to qualitatively change the process.

 The process of alloying and coating is simplified, since the process goes along with control and the quality of the material is constantly under control (simultaneously with alloying), while the necessary adjustment is constantly made in terms of the number of alloying or surface-applied elements, as well as the magnitude of the acting on the plasma, the melt zone or the surface of the product pulses of electromagnetic energy.

 In addition, the advantage of the combined control method is the variety of materials of the obtained films, dielectrics, metals, including refractory, multicomponent compounds.

 The method allows to obtain products and billets (pipes and gun barrels, ingots for rolling armor, etc.) that are close in properties to damask steels and especially chemically pure materials upon recrystallization after cleaning from polycrystals to single crystals using known technologies of zone crucibleless melting , and also to receive products entirely from a pure single crystal, controlling and managing all these processes at any stage of the technology.

 None of the known control methods, including the prototype, allows controlling the controlled parameters and adjusting the technological process according to the control results in one direction or another in the control process. The proposed method of combined control allows this and eliminates the appearance of marriage in the process.

 The proposed control method can be used to implement unmanned technologies.

 In addition, the proposed method of combined non-destructive testing together with methods of plasma metallurgy and the attraction of powder metallurgy makes it possible to obtain ultrapure materials, alloys and single crystals from powders of iron oxides and other metals and alloys by direct technology, powder prefabricated oxides and zone melting in hydrogen or carbon and their plasma, to restore ultrapure metals and alloys and even to obtain finished products from the pore filled in with them using lost-wax models in crucible forms shka, and if necessary, parts of single crystals for several passes and then zone melting recrystallization of the single crystal embryo to produce a single crystal Damascus steel or recrystallization to obtain layered polycrystal with layers of single crystals with the properties of Damascus steel.

Claims (2)

 1. METHOD OF ELECTROMAGNETIC-ACOUSTIC NON-DESTRUCTIVE CONTROL OF PRODUCTS, which consists in the fact that mechanical vibrations are excited through a plasma layer by introducing a constant and alternating electromagnetic field through the plasma layer, the parameters of these vibrations are measured and the quality of the controlled product is determined by the measurement results, characterized in that the product is in the control zone is heated to the melt temperature.  2. The method according to p. 1, characterized in that when controlling the quality of the single crystal in the process of obtaining it, the control zone and heating the product in the direction from the workpiece of the single crystal with a single crystal growth rate.

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