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CN-121988899-A - Underwater laser cleaning and cutting composite machining device and application method

CN121988899ACN 121988899 ACN121988899 ACN 121988899ACN-121988899-A

Abstract

The invention belongs to the technical field of nuclear facility retirement, and particularly discloses an underwater laser cleaning and cutting composite processing device and a use method thereof, wherein the cleaning and cutting are realized by scanning refraction and reflection of an X/Y axis vibrating mirror group and a dichroic mirror on cleaning laser and transmission of the dichroic mirror on cutting laser, and a common field lens is used for realizing coaxial focusing; the bottom is provided with a gas-liquid coaxial composite nozzle, which can independently regulate and control the auxiliary air flow of the center and the annular high-pressure laminar flow, and is matched with millisecond process switching to complete immediate cutting after cleaning at the same underwater station. Aiming at the problems of low efficiency, high safety risk, multiple secondary pollution, poor cutting quality and the like in the decontamination and disassembly processes of the high-level metal parts of the nuclear power station, the invention does not generate radioactive waste liquid, effectively avoids secondary pollution, remarkably improves the cutting quality, the operation safety and the system reliability, and is suitable for green and efficient retired operation under the high-radioactivity environment.

Inventors

  • MIAO QIANG
  • LU HAIFENG
  • LIANG WENPING
  • FANG YU
  • YOU XINYUE
  • Guo Yuanxue

Assignees

  • 南京航空航天大学

Dates

Publication Date
20260508
Application Date
20260206

Claims (10)

  1. 1. An underwater laser cleaning and cutting composite processing device, which is characterized by comprising: the laser cutting device comprises a sealing shell (1), wherein a laser cleaning input end (3) and a laser cutting input end (5) are arranged at the top of the sealing shell (1), a cutting head (4) is arranged at the lower part of the sealing shell (1), and a workpiece (16) is positioned at the lower part of the cutting head (4); a coaxial double-light-path system and a shared focusing system are arranged in the sealed shell (1); a coaxial dual optical path system for directing a cleaning laser beam from a laser cleaning input (3) and a cutting laser beam from a laser cutting input (5) to a common focusing system; A common focusing system for focusing the cleaning and cutting laser beams through the cutting head (4) to the same machining plane on the workpiece (16); the lower part of the sealing shell (1) is also provided with a coaxial composite nozzle assembly (10), the coaxial composite nozzle assembly (10) is positioned at the periphery of the cutting head (4), an annular water jet channel is formed between the coaxial composite nozzle assembly and the cutting head (4), and an outlet at the lower part of the water jet channel is a nozzle.
  2. 2. The underwater laser cleaning and cutting composite processing device according to claim 1, wherein the coaxial double-light-path system comprises a dichroic mirror (6) and a scanning X/Y axis vibrating mirror group (9), wherein the scanning X/Y axis vibrating mirror group (9) is fixed below a laser cleaning input end (3), and the dichroic mirror (6) is fixed below a laser cutting input end (5); the cleaning laser beam from the laser cleaning input end (3) is transmitted to the shared focusing system after being refracted by the scanning X/Y axis vibrating mirror group (9) and reflected by the dichroic mirror (6); The cutting laser beam from the laser cutting input end (5) penetrates through the dichroic mirror (6) and then is transmitted to the common focusing system; the cleaning laser and the cutting laser are coaxially irradiated to a common focusing system.
  3. 3. The device for combined cleaning and cutting by using underwater laser according to claim 2, wherein the optical coating of the dichroic mirror (6) is configured such that the reflectivity of the pulse laser with the wavelength of 1064 nm is not less than 98% and the transmissivity of the continuous laser with the wavelength of 1080 nm is not less than 95%.
  4. 4. The underwater laser cleaning and cutting composite processing device according to claim 2 is characterized in that the common focusing system comprises an F-Theta field lens (7) and a protective lens (8), and the cleaning laser and the cutting laser coaxially and sequentially pass through the F-Theta field lens (7) and the protective lens (8).
  5. 5. The device for combined machining of underwater laser cleaning and cutting according to claim 4, wherein a sealing inert gas inlet (11) and a central auxiliary gas inlet (12) are arranged on the sealing shell (1), the sealing shell (1) is internally provided with a pipeline connected with the central auxiliary gas inlet (12) and used for guiding auxiliary gas to the center of the cutting head (4) to form a gas curtain, and the gas curtain area covers coaxial beams of the cleaning laser and the cutting laser; the lower part of the sealing shell (1) is provided with an annular high-pressure water jet inlet (13) communicated with the water jet channel.
  6. 6. The underwater laser cleaning and cutting combined processing device according to claim 5 is characterized in that a beam expander (17) is fixedly arranged between the dichroic mirror (6) and the scanning X/Y axis vibrating mirror group (9), and a cleaning laser beam passes through the beam expander (17) to reach the dichroic mirror (6).
  7. 7. The underwater laser cleaning and cutting combined machining device according to claim 1 or 5 is characterized in that a collimating mirror (2) is arranged on each of a laser cleaning input end (3) and a laser cutting input end (5), and a miniature pressure sensor and a flowmeter (18) are further arranged on a cutting head (4).
  8. 8. The method of using an underwater laser cleaning and cutting composite processing device according to claim 5, comprising the steps of: step 1, placing a high-level metal workpiece to be treated in a special boric acid pool for a nuclear power station; Step 2, positioning the composite processing device above a to-be-processed area of the workpiece by a robot, and adjusting the distance between a cutting head (4) and a nozzle outlet and the surface of the workpiece to be 3-10 mm; Starting a pulse fiber laser of a laser cleaning input end (3) and a gas supply and water supply system, controlling the pressure of inert gas to be 0.4-0.6 Mpa, the flow rate of auxiliary gas to be 10-15L/min, the pressure of water flow to be 0.5-1.2 Mpa, discharging inert gas and auxiliary gas from an outlet of a cutting head (4), discharging high-pressure water jet from a nozzle, and cleaning laser beams sequentially passing through an F-Theta field lens (7) and a protective lens (8) to be ejected out of the cutting head (4) after refraction of a scanning X/Y axis vibrating lens group (9) and reflection of a dichroic mirror (6) to perform cleaning treatment on the surface of a workpiece; step 4, after the cleaning is finished, the control system turns off the pulse fiber laser in 100 ms and synchronously starts the continuous fiber laser of the laser cutting input end (5); step 5, adjusting parameters of a gas supply system and a water supply system, adjusting the flow rate of auxiliary gas to 15-20L/min, increasing the pressure of water flow to 1.5-2.5 MPa, and controlling a continuous fiber laser to perform underwater cutting on a clean area of the cleaned workpiece (16); And 6, after cutting is completed, all the laser sources and the fluid system are turned off, and the robot drives the composite processing head to reset.
  9. 9. The method of claim 8, wherein the pulsed fiber laser in step 3 has a power of 100-500W, a wavelength of 1064 nm, a pulse width of 50-300 ns, and a scanning speed of 500-2000 mm/min; The power of the continuous fiber laser in the step 5 is 6-12 kW, the wavelength is 1080 nm, and the cutting speed is 10-100 mm/min.
  10. 10. The method of claim 8, wherein in step 3 and step 5, the acoustic emission signal or the plasma spectrum of the processing area is collected in real time, and the laser power or the water flow pressure is dynamically adjusted according to the feedback signal.

Description

Underwater laser cleaning and cutting composite machining device and application method Technical Field The invention belongs to the technical field of nuclear facility retirement, and particularly relates to an underwater composite processing head integrating laser cleaning and laser cutting functions and a cooperative processing method thereof, which are particularly suitable for metal component surface cleaning and cutting operation in the nuclear facility retirement field. Background As the global first commercial nuclear power plant comes into end of service, nuclear facility decommissioning has become a key challenge for sustainable development of nuclear power. In the decommissioning process, core metal components such as reactor pressure vessels, steam generators, pipeline systems and the like have extremely high radioactivity due to long-term neutron irradiation, and the reactor pressure vessels, steam generators, pipeline systems and the like belong to typical high-dose decommissioning metal wastes. The safe and efficient processing of the components directly relates to the progress, cost and environmental safety of retirement engineering. Currently, the treatment of such high-level metallic pieces generally follows the principle of "decontamination followed by disintegration". Surface cleaning is a primary step aimed at removing or stripping loose radioactive contaminants (such as scale, corrosion products and adsorbed fission products) from the surface to reduce the radiation dose for subsequent operations and to reduce the amount of final waste. Although the traditional chemical decontamination method has a certain effect, a large amount of secondary radioactive waste liquid is generated, the treatment difficulty is high, the cost is high, and the corrosion to the matrix metal is easy to cause. The mechanical polishing rule has dust diffusion risk, is easy to cause radioactive aerosol leakage and forms serious threat to operators and environment. Disassembly cutting is a core process of retirement, and large-scale metal components are required to be divided into small blocks which are convenient to transport and dispose. Although the traditional methods such as underwater plasma cutting, electric arc sawing and the like can be carried out in a shielding water tank, the problems of large heat affected zone, low cutting precision, large slag and smoke dust generation and the like are common. These byproducts not only re-adsorb radionuclides to form new sources of pollution, but also can clog the space of underwater operations, increasing the complexity of remote operations. In recent years, the laser processing technology has great potential in the nuclear decommissioning field due to the advantages of non-contact, high precision, small heat affected zone and the like. However, the prior art still faces a serious bottleneck that on one hand, the surface of a metal piece to be treated is generally covered with a compact oxide layer and refractory pollutants, the direct laser cutting can cause low energy coupling efficiency, unstable cutting process and even cause plasma shielding effect to interrupt processing, and on the other hand, if laser cleaning and laser cutting are implemented step by step as two independent working procedures, the workpiece needs to be cleaned in a water negative pressure working room firstly, and then is transferred into a water tank to carry out cutting work by means of shielding and hoisting tools. On one hand, the operation flow needs to consume a great deal of manpower and material resources, and on the other hand, secondary pollution (such as adsorption of suspended particles in water or precipitation of bubbles) is very easy to occur in the process of transferring or waiting under water of the workpiece, so that the early cleaning effect is greatly reduced, and an ideal clean surface cannot be provided for high-quality cutting. More importantly, the existing laser equipment adopts a single-function head design, and different laser processing equipment needs to be replaced for cleaning and cutting, so that the operation flow is complex and the efficiency is low. Therefore, development of an underwater composite processing head and a cooperative processing method integrating efficient laser cleaning and precise laser cutting are needed. The device can realize seamless connection of cleaning and cutting in the same station and the same underwater environment, thoroughly avoid secondary pollution risk, ensure that the high-level metal parts finish retirement treatment under the conditions of high safety and high efficiency through innovative optical and fluid integrated design, and provide key technical support for green and economic retirement of nuclear facilities. Disclosure of Invention The invention aims to solve the problems that after the production of a prestress steel strand in the prior art is finished, the steel strand needs to be wound into a ring manually,