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BR-102019023553-B1 - SYSTEM AND METHOD OF WELDING BY ELECTROMAGNETIC WAVES

BR102019023553B1BR 102019023553 B1BR102019023553 B1BR 102019023553B1BR-102019023553-B1

Abstract

WELDING SYSTEM AND METHOD. The present invention presents a welding system in which electromagnetic waves are used to provide the necessary energy for welding, indirectly, to the base metal and the filler metal. The filler metal is melted and inserted into a welding mold in order to join at least two metallic bodies, referred to as base metals. Additionally, the present invention presents a step-by-step welding method for performing welding using electromagnetic waves, preferably implemented by the aforementioned system.

Inventors

  • AUTELIANO ANTUNES DOS SANTOS JUNIOR
  • MARCOS AURÉLIO CORRÊA MACHADO
  • JOSÉ LAVAQUIAL BIOSCA NETO
  • RAFAEL NUNES SEGANTINE

Assignees

  • UNIVERSIDADE ESTADUAL DE CAMPINAS - UNICAMP
  • MICROONDAS DESENVOLVIMENTO E TECNOLOGIAS LTDA

Dates

Publication Date
20260317
Application Date
20191108

Claims (20)

  1. 1. Welding system characterized by welding at least two metallic bodies, using electromagnetic waves as an energy source and comprising a welding mold (3); a first resonant cavity (4); a guide duct (5); and a fusion unit (6); wherein the resonant cavity (4) uniformly distributes the electromagnetic waves throughout the entire length of the welding mold; the welding mold (3) receives the energy from the electromagnetic waves, dissipates this energy by means of heat and transmits it to the base metals; the fusion unit (6) melts the filler metal; and the guide duct (5) conducts the molten filler metal into the welding mold (3).
  2. 2. System, according to claim 1, characterized in that the welding mold (3) is composed of susceptor ceramic material, has a shape compatible with the negative of the base metal bodies (1), receives and encloses part of the base metal bodies (1), arranges them in such a way as to provide the proper positioning for welding and allows the insertion of the filler metal (7) inside it.
  3. 3. System, according to claim 1 or 2, characterized in that the arrangement of the base metals (1) inside the mold (3) leaves a gap (2) between them.
  4. 4. System, according to claim 1, 2 or 3, characterized in that the mold (3) has a hole (3.1) preferably in its upper part and openings preferably in its side part.
  5. 5. System according to claim 1, characterized in that the first resonant cavity (4) is a metallic structure, enclosing the mold (3) and part of the base metal bodies (1) and uniformly distributing the electromagnetic waves throughout the entire extent of the mold (3).
  6. 6. System, according to claim 1 or 5, characterized in that the first resonant cavity (4) has a hole preferably in its upper part, concentric and of the same shape and size as the hole (3,1) of the mold (3), allowing the proper insertion of the filler metal (7) into the mold (3), having openings preferably in its lateral part, concentric, of the same shape and size as the openings of the mold (3), allowing the insertion of the base metals (1).
  7. 7. System, according to claim 1, 5 or 6, characterized in that the first resonant cavity (4) preferably has magnetrons (4.1) for generating electromagnetic waves.
  8. 8. System, according to claim 1, 5 or 6, characterized in that the first resonant cavity (4) has the possibility of obtaining means to receive electromagnetic waves coming from waveguides.
  9. 9. System, according to claim 1, characterized in that the guide tube (5) conducts the molten filler metal (7) into the mold (3), is preferably made of tungsten, has its lower end connected to the upper hole of the first resonant cavity (4) and its upper end connected to the lower end of the funnel (6.6) of the invention unit (6).
  10. 10. System according to claim 1, characterized in that the melting unit (6) melts the filler metal (7) and conducts the molten filler metal (7) to the guide tube (5) and to the welding mold (3) and further comprises, in its preferred configuration, at least: a crucible (6.1); a second resonant cavity (6.2); a magnetron (6.3), a waveguide (6.4); a valve (6.5); and a funnel (6.6).
  11. 11. System, according to claim 1 or 10, characterized in that the crucible (6.1) is a susceptor container, receives the filler metal (7), receives energy from electromagnetic waves, dissipates such energy in the form of heat to the filler metal (7), is vertically hollow, is disposed inside the second resonant cavity (6.2) and has its lower hollow end controlled by the valve (6.5).
  12. 12. System, according to claim 1 or 10, characterized in that the second resonant cavity (6.2) is a metallic structure, encloses the crucible (6.1), uniformly distributes the electromagnetic waves throughout the entire extent of the crucible (6.1), has a concentric opening in its lower part, of the same shape and size as the crucible (6.1).
  13. 13. System according to claim 1 or 10, characterized in that the magnetron (6.3) generates the electromagnetic waves, supplies the electromagnetic waves to the waveguide (6.4) and is connected to the waveguide (5).
  14. 14. System, according to claim 1 or 10, characterized in that the waveguide (6.4) receives, guides and transmits the electromagnetic waves generated by the magnetron (6.3) to the second resonant cavity (6.2), is connected to the magnetron (6.3) at one of its ends and is connected to the second resonant cavity (6.2).
  15. 15. System, according to claim 1 or 10, characterized in that the valve (6.5) contains the filler metal (7) inside the crucible (6.1) and allows the same to be conducted to the funnel (6.6), once it is melted, preferably being a sliding valve, having an opening (6.5.1) and being positioned between the crucible (6.1) and the funnel (6.6).
  16. 16. System, according to claim 1, 10 or 14, characterized in that said valve (6.5) has closed and open working positions, wherein in the closed position the valve (6.5) contains the filler metal (7) inside the crucible (6.1) and in the open position the valve (6.5.1) allows the filler metal (7) to be conveyed to the funnel (6.6).
  17. 17. System, according to claim 1 or 10, characterized in that the funnel (6.6) allows the conveyance of the filler metal (7) from the crucible (6.1) to the guide tube (5), is connected at its upper end to the valve (6.5) and at its lower end to the guide tube (5).
  18. 18. Welding method characterized by providing heating energy to the base metals and melting the filler metal through electromagnetic waves, allowing control of heating or cooling temperature with a precision of 0.5°C, providing the establishment of heating and cooling ramps with precision and speed, comprising the following steps: 1) Preheating: the bodies to be welded are properly positioned with part of them inside a susceptor mold and with a gap between them, electromagnetic waves are emitted and directed to the susceptor mold, the susceptor mold receives the energy of the electromagnetic waves and dissipates them in the form of heat, the mold heats the parts of the base metal bodies contained inside the mold; 2) Casting: the filler metal is placed in a susceptor container, electromagnetic waves are emitted and directed towards the susceptor container, the susceptor container receives the energy from the electromagnetic waves and dissipates it in the form of heat, the susceptor container heats and melts the filler metal contained within it; 3) Conduction: the filler metal is inserted into the susceptor mold and the gap between the base metals is filled with molten filler metal; and 4) Welding.
  19. 19. Method according to claim 18, characterized in that the electromagnetic waves are contained in the microwave spectrum and are preferably 915 ± 25 MHz or 2,450 ± 50 MHz.
  20. 20. Method, according to claim 18, characterized in that the filling of the gap is carried out with the conductor of the molten filler metal moving according to the level of molten metal contained in the gap.

Description

Field of invention: [1] The present invention falls within the field of metallurgical engineering, more precisely in the construction of structural and mechanical components and the welding of metal parts, as an advantageous alternative to traditional welding methods. Fundamentals of the invention: [2] Despite technological advances in new methods of manufacturing parts, welding remains the most important industrial process for manufacturing metal parts and joining metal parts. Welding processes are also used in the recovery of worn parts, for the application of coatings with special characteristics on metal surfaces, and for cutting metal parts. The success of welding processes is mainly associated with the operational simplicity of welding processes, which facilitates the training of specialized labor and, secondly, the automation of welding processes. [3] Despite the operational simplicity of welding techniques, the fact that, during the process, the material to be welded is subjected to extreme conditions due to the application of a high amount of energy to a small volume of material should not be minimized, which can result in changes in the physical-chemical and structural properties of the original material. Ignorance or disregard for these changes can result in unexpected problems. [4] The welding process is defined as a method of joining metals, based on the appearance of microscopic interatomic and intermolecular forces. The operation aims to obtain the joining of metal parts, verifying in the welded joint the continuity of physical, chemical and metallurgical properties. Several welding processes have been developed in an attempt to achieve better operating conditions, economy of inputs and control of the physical, chemical and mechanical properties of the welded materials. [5] In general, welding processes can be classified into two large groups. The first comprises autogenous or pressure welding, where at least one of the metals of the parts joined by the weld reaches the melting point through the application of heat. Once fusion is achieved, the metals in the joint mix and, after solidifying, provide continuity to the joint. [6] Among the most commonly used pressure welding processes, ultrasonic welding, friction welding, forging welding, resistance welding, diffusion welding and explosion welding stand out. In these processes there is no addition of metal, and the redistribution of the liquefied metal often leads to defects such as the appearance of undercuts on the sides of the welds. For applications requiring fatigue resistance, such defects are unacceptable. [7] The second group comprises processes in which filler metal is used, where the (total or partial) fusion of the joined parts does not occur and where the spaces between them are filled by the added metal. Among the most used techniques in this type of welding are electric arc welding (using metal rods or wires that are melted by the heat of the arc), with or without protection by means of inert gas, highlighting MIG/MAG welding, plasma welding, TIG welding, gas welding, laser welding and shielded metal arc welding. [8] Despite their widespread use, these processes have some drawbacks: for example, arc welding with coated electrodes produces highly polluting gases and fumes that affect the operator's health. In gas welding, only a fraction of the energy is effectively applied to the parts during the process, with the rest of this heat being wasted, resulting in a clear reduction in efficiency. In addition, temperature control of the parts subjected to heating is poor, which can result in underheating or overheating, which can cause deformation. Finally, obtaining an adequate surface finish is a problem that requires extreme process control and operator competence. [9] One of the ways to apply the energy needed to perform welding is through electromagnetic waves, preferably the microwave spectrum. Microwave energy is a unique source because it produces heat within the processed materials. This property results in shorter processing times, higher yield and usually a superior quality in the finished product compared to that obtained with conventional processing techniques. [10] Dielectric heating results from the ability of dielectric materials to absorb electromagnetic energy and release it in the form of heat. Thus, heating is produced by the interaction of materials, which have dielectric characteristics favorable to heating, with the electric field of microwave energy. [11] The heating resulting from this interaction is mainly due to two effects. In solid dielectric materials, which have electrically charged particles free to move within a bounded region of the material, such as π electrons in carbon materials, the application of an electric field by means of microwaves induces an electric current in the material in phase with the electric field. As the electrons cannot follow the phase changes of the electric field, due to their r