Method and apparatus for controlling welding temperature gradient based on neutron source residual stress detection

Abstract

This invention relates to a welding temperature gradient control method and apparatus based on neutron source residual stress detection, belonging to the field of welding control technology. This technology establishes a correlation between laser power, beam size, scanning rate, metal type, and temperature by constructing a temperature field data acquisition module and a heating and cooling module for the welding process, and by using laser-assisted local heating and forced substrate cooling devices. It develops a temperature gradient control method to achieve online physical simulation of the temperature gradient between the welding zone and the substrate, solving the problem of mismatch between the welding cooling rate and the neutron data acquisition rate, and realizing in-situ online testing of the stress field near welding conditions.

Description

Technical Field

[0001] This invention belongs to the field of welding control technology, and relates to a welding temperature gradient control method and device based on neutron source residual stress detection. Background Technology

[0002] Welding is one of the main methods for manufacturing and forming metal engineering components, and it is widely used in aviation, aerospace, transportation, nuclear energy and other fields. The welding stress field is a key factor leading to unexpected deformation of weldments and affecting their service performance. Welding stress field detection and control are crucial means to optimize welding processes and improve weldment quality. Domestic and international research institutions have conducted extensive off-site detection of welding stress fields using neutron diffraction, gaining considerable understanding of the distribution law of residual stress in weldments. However, the formation and evolution mechanism of the stress field during welding remains unclear. The key constraint on the development of in-situ welding stress field detection technology lies in the mismatch between the welding cooling rate and the neutron data acquisition speed. Currently, the neutron diffraction data acquisition speed is insufficient to fully capture the entire evolution process of the welding stress field. Developing high-temporal-resolution stress detection technology and weldment temperature gradient control technology are currently two main research directions. Developing welding temperature gradient control technology, achieving online coupling between the welding process and the neutron source, and establishing and developing methods and evaluation standards for controlling welding residual stress are urgent needs for improving the welding quality of metal engineering components in my country. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a welding temperature gradient control method and apparatus based on neutron source residual stress detection.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A welding temperature gradient control method based on neutron source residual stress detection includes the following steps:

[0006] S1 builds a temperature field data acquisition system to obtain the temperature field distribution characteristics during the welding heating and cooling process;

[0007] S2 is equipped with heating and cooling modules. Laser-assisted heating and forced substrate cooling devices are introduced during the welding process to solve the mismatch between the welding cooling rate and the neutron data acquisition speed.

[0008] The relationship between S3 laser power, beam size, scanning rate, and temperature was analyzed to optimize local laser-assisted heating process parameters and achieve temperature gradient control during welding.

[0009] Optionally, in step S1, the temperature field distribution characteristics during the welding heating and cooling process are obtained by using an infrared thermometer and a thermocouple.

[0010] Optionally, in step S1, several sets of parallel temperature test sections are set along the direction of the weld before welding. Several thermocouples are set in each set of temperature test sections to collect temperature signals and send them to the PLC. The host computer displays and saves the temperature data.

[0011] Optionally, in step S2, the laser-assisted heating device includes a laser heater and an automatic control unit, and the laser heater enables single-point and reciprocating scanning auxiliary heating.

[0012] Optionally, in step S2, the scanning rate of the laser heater is 0-1.2 mm / s, the laser power is 0-4 KW, the spot diameter is 0.1-0.5 mm, and the wavelength is 1-4 μm.

[0013] Optionally, in step S2, the substrate forced cooling device includes a copper mold and a circulating water cooling control unit.

[0014] Optionally, in step S2, the cooling water flow rate is 0-1.5 mm / s.

[0015] A welding temperature gradient control device based on neutron source residual stress detection is used for welding control of a substrate. It includes a substrate forced cooling device for cooling the substrate, a laser heater for heating the substrate, a robot for welding the substrate, and a displacement control device for adjusting the position of the substrate. It also includes an incident neutron source and a neutron detector used together to detect neutron source residual stress on the substrate, wherein the incident neutron source and the neutron detector are disposed on both sides of the substrate.

[0016] Optionally, it also includes a thermocouple whose position matches the weld seam of the substrate, and the thermocouple is connected to a temperature data acquisition device.

[0017] Optionally, an infrared thermometer for measuring weld temperature is also included.

[0018] The beneficial effects of this invention are as follows:

[0019] This invention addresses the problems of long response time in high-temperature regions, inability to measure specific areas, and relatively low accuracy of infrared temperature measurement by using a combination of an infrared thermometer and thermocouples. This allows for accurate acquisition of the temperature field distribution characteristics (test range: 0–1600°C) during welding heating and cooling. For the TIG welding process, multiple parallel temperature test sections are designed along a direction perpendicular to the weld seam. Each section has multiple thermocouples arranged from the weld seam to the base material. The data acquisition and processing device is connected to the thermocouples to accurately acquire temperature field data. This invention also constructs a welding joint heating and cooling module, including laser-assisted heating and a forced substrate cooling device, resolving the mismatch between the welding cooling rate and the neutron data acquisition speed.

[0020] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0022] Figure 1 This is a schematic diagram of the device of the present invention;

[0023] Figure 2 This is a schematic diagram of the layout of thermocouples and infrared thermometers in the temperature field control subsystem.

[0024] Figure 3 This is a diagram showing the location distribution of temperature sensors;

[0025] Figure 4 This is a schematic diagram of welding temperature field control.

[0026] Figure 5 The cooling rate of the heat-affected zone under different laser heating powers.

[0027] Figure reference numerals: 1. Temperature data acquisition device; 2. Laser heater; 3. Infrared thermometer; 4. Thermocouple; 5. Substrate forced cooling device; 6. Incident neutron source; 7. Neutron detector; 8. Robotic arm; 9. Displacement control device; 10. Waste gas collection device; 11. Weld. Detailed Implementation

[0028] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0029] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0030] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0031] Please see Figures 1-5 This invention relates to a welding temperature gradient control method based on neutron source residual stress detection, specifically including:

[0032] (1) A temperature field data acquisition system is constructed. Infrared thermometer 3 and thermocouples 4 are used in conjunction to solve problems such as the long response time of thermocouples 4 in high-temperature areas, the inability to measure certain areas, and the relatively low accuracy of infrared temperature measurement. This enables accurate acquisition of the temperature field distribution characteristics (test range: 0–1600℃) during welding heating and cooling. For the TIG welding process, three sets of parallel temperature test sections are designed along a direction perpendicular to the weld 11. Each set consists of seven thermocouples 4 arranged from the weld 11 to the base material. The data acquisition and processing device is connected to the thermocouples 4 to accurately acquire temperature field data. The system also includes an incident neutron source 6 and a neutron detector 7 used in conjunction to detect residual stress on the substrate. The incident neutron source 6 and the neutron detector 7 are located on both sides of the substrate.

[0033] (2) Construct a welding joint heating and cooling module, including a laser-assisted heating device and a substrate forced cooling device 5, to solve the mismatch between the welding cooling rate and the neutron data acquisition speed. The laser heater 2 has a power of 4KW.

[0034] (3) The laser-assisted heating device mainly consists of a laser heater 2 and an automatic control unit, which is used to heat the welding area. It can realize single-point and reciprocating scanning assisted heating with a scanning rate of 0-1.2 mm / s. The substrate forced cooling device 5 mainly consists of a copper mold and a circulating water cooling control unit, which is used to cool the substrate area.

[0035] (4) Establish the correspondence between laser power, beam size, scanning rate and temperature, optimize the local laser-assisted heating process parameters, and achieve effective control of temperature gradient during welding.

[0036] The specific experimental steps of this invention are as follows:

[0037] (1) This experiment first involves TIG welding of two 6061 aluminum alloy pieces measuring 50mm × 20mm × 1mm. The welding current is 290A, the welding voltage is 17.5V, and the welding speed is 14m / h. Before welding, three parallel temperature test sections were designed along a direction perpendicular to weld 11. Each section had seven thermocouples 4 arranged from weld 11 to the base material. The temperature data acquisition device 1 was connected to the thermocouples 4, and the welding points of the thermocouples 4 were fixed or attached to the welding material to achieve real-time acquisition of the temperature of each area of ​​the blank during the welding process. The temperature signal was sent to the PLC, and the host computer displayed the temperature data and saved it to the SQL Server database. The positions of the thermocouples 4 are as follows: Figure 3 As shown in the figure. Simultaneously, an infrared thermometer is used to measure the temperature change in the welding area in real time, accurately acquiring the temperature field distribution characteristics (test range: 0~1600℃) during welding heating and cooling processes. The specific layout of the temperature measurement module is shown in the figure. Figure 2 As shown.

[0038] (2) A laser is installed on the welding work platform. The laser heater 2 has a power of 4KW. At the same time, a substrate forced cooling device 5 is installed on the welding table base. The mismatch between the welding cooling rate and the neutron data acquisition speed is solved by the direct layout of the TIG welding robot (manipulator 8), laser heater 2 and substrate forced cooling device 5. Figure 1 The diagram shows the layout of the TIG welding robot (manipulator 8), laser, and cooling device. The device of this invention provides a displacement control device 9 for adjusting the position of the substrate. In this embodiment, all of the above devices are located inside the housing, and an exhaust gas collection device 10 is installed on the housing.

[0039] (3) During the sample welding process, a laser heater 2 is used to perform single-point and reciprocating scanning auxiliary heating on the welding area. The scanning rate is 0-1.2 mm / s, the laser power is 0-4 KW, the spot diameter is 0.1-0.5 mm, and the wavelength is 1-4 μm. At the same time, the substrate forced cooling device 5 mainly consists of a copper mold and a circulating water cooling control unit, which is used to cool the substrate area. The cooling water flow rate is 0-1.5 mm / s. By adjusting the temperature change in the welding heat-affected zone under different laser power, beam size, and scanning rate, the correspondence between laser power, beam size, scanning rate, and temperature is established. At the same time, the local laser-assisted heating process parameters are optimized to achieve effective control of the temperature gradient during the welding process. The specific temperature gradient control diagram is shown in the figure. Figure 4 As shown.

[0040] (4) Figure 5To illustrate the temperature changes in the heat-affected zone (HAZ) under different laser-assisted heating powers, when the laser heating power is 0 (shown by the black line), the temperature of the HAZ drops rapidly, reaching approximately 300 degrees Celsius within 250 ms. However, when the laser heater 2 is set to 3 kW power, 0.26 mm diameter, and 1.06 μm wavelength, the cooling rate of the HAZ decreases dramatically, reaching 0.6 K / ms, demonstrating effective control of the temperature gradient.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A welding temperature gradient control method based on residual stress detection of a neutron source, characterized by, The welding temperature gradient control device based on neutron source residual stress detection is used for the welding control of a substrate, and includes a substrate forced cooling device for cooling the substrate, a laser heater for heating the substrate, a mechanical hand for welding the substrate, a displacement control device for adjusting the position of the substrate, and an incident neutron source and a neutron detector used in combination to perform neutron source residual stress detection on the substrate, the incident neutron source and the neutron detector being arranged on both sides of the substrate; further including a thermocouple arranged at a position matching the weld of the substrate and an infrared temperature measuring instrument for measuring the temperature of the weld, the thermocouple being connected to a temperature data collector; a plurality of groups of parallel temperature test sections are arranged along the direction of the weld before welding, a plurality of thermocouples are arranged in each group of temperature test sections, and temperature signals are collected into a PLC, and the temperature data are displayed and saved by an upper computer; The control method comprises the following steps: Step S1, a temperature field data acquisition system is built, and the temperature field distribution characteristics in the welding heating and cooling process are obtained by the combination of an infrared temperature measuring instrument and a thermocouple; Step S2, a heating module and a cooling module are built, and a laser auxiliary heating device and a substrate forced cooling device are introduced during the welding process to solve the problem of mismatch between the welding cooling rate and the neutron data acquisition speed; Step S3, a corresponding relationship between the laser power, the beam spot size, the scanning rate and the temperature is established, the local laser auxiliary heating process parameters are optimized, and the temperature gradient control during the welding process is realized.

2. The welding temperature gradient control method based on neutron source residual stress detection of claim 1, wherein: In step S2, the laser auxiliary heating device includes a laser heater and an automatic control unit, and single-point and reciprocating scanning auxiliary heating are realized by the laser heater.

3. The welding temperature gradient control method based on residual stress detection by a neutron source according to claim 2, characterized by: In step S2, the scanning rate of the laser heater is 0-1.2 mm / s, the laser power is 0-4 kW, the spot diameter is 0.1-0.5 mm, and the wavelength is 1-4 μm.

4. The welding temperature gradient control method based on residual stress detection by a neutron source according to claim 1, characterized by: In step S2, the substrate forced cooling device includes a copper mold and a circulating water cooling control unit.

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