Welding method for pressure measuring tube

Abstract

The present application relates to the field of welding technology, and more specifically, to a method for welding a pressure gauge tube, wherein the pressure gauge tube includes a capillary tube and a transition block, and the method includes: laser welding the gap on one side of the capillary tube and the transition block; after completing the laser welding, vacuum brazing the gap on the other side. In the present application, by using different welding methods on both sides of the pressure gauge tube structure to weld the capillary tube and the transition block to the pressure gauge component, the disadvantage of the vacuum furnace limiting the overall size of the engine is overcome; laser welding technology has the advantages of concentrated energy, low heat input, and a small heat-affected zone, which reduces the welding deformation of thin-walled capillaries and forms a reliable connection at the bottom of the connection between the capillary tube and the transition block, thus overcoming the defect of sudden drop in high-temperature performance of vacuum brazing; and vacuum brazing is used to strengthen the weld joints in batches.

Description

Technical Field

[0001] The present application relates to the field of welding technology, and in particular to a welding method for a pressure measuring tube. Background Art

[0002] With the development of engines in my country, the development of supersonic ramjet engines urgently requires breakthroughs. Supersonic ramjet combustion chambers are developing towards high temperature rise. To analyze and monitor aerodynamic pressure and flow field distribution, installing pressure taps on the engine's outer surface is the most common method for measuring aerodynamic pressure and flow field distribution. However, the aerodynamic heat generated by high Mach speeds makes the original plastic pipe pressure taps unsuitable for harsh operating conditions, necessitating the use of metal pressure taps and reliable connections. Existing metal pressure taps are connected using vacuum brazing or laser welding. However, the currently used vacuum brazing processes suffer from low temperature resistance, low joint strength, and a sudden drop in high-temperature performance between the engine and the metal pressure tap. Furthermore, the vacuum furnace limits the overall size of the engine. Laser welding, due to the thin-walled structure of the pressure tap, is prone to defects at the arc start and end points due to high heat input. To control heat input, the effective weld penetration is limited, making it unreliable for a reliable connection between the supersonic ramjet engine and the metal pressure tap.

[0003] Based on this, those skilled in the art are in urgent need of a welding method for a pressure measuring tube that can improve the reliability of the connection between the pressure measuring tube and the engine. Summary of the Invention

[0004] An embodiment of the present application provides a method for welding a pressure measuring tube, thereby improving the reliability of the connection between the pressure measuring tube and the engine, at least to a certain extent.

[0005] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by practice of the present application.

[0006] According to one aspect of an embodiment of the present application, a welding method for a pressure measuring tube is provided, wherein the pressure measuring tube includes a capillary tube and a transition block, and the method includes: performing laser welding on a gap on one side of the capillary tube and the transition block; after completing the laser welding, performing vacuum brazing on the gap on the other side.

[0007] In some embodiments of the present application, the laser welding includes: setting the welding parameters of the laser welding equipment to first welding parameters, and determining the laser welding path according to the structure of the pressure measuring tube; performing at least one point welding in a protective gas environment according to the first welding parameters and the laser welding path; adjusting the welding parameters of the laser welding equipment to second welding parameters, and performing continuous welding in the protective gas environment according to the second welding parameters and the laser welding path.

[0008] In some embodiments of the present application, the welding parameters of the laser welding equipment are set as first welding parameters, including: the laser power is set to 100W to 300W, the welding speed is set to 1200mm / min to 2000mm / min, and the defocus amount is set to -5mm to +5mm.

[0009] In some embodiments of the present application, the welding parameters of the laser welding equipment are set to second welding parameters, including: the laser power is set to 800W to 2500W, the welding speed is set to 1200mm / min to 2000mm / min, and the defocus amount is set to -5mm to +5mm.

[0010] In some embodiments of the present application, the vacuum brazing of the gap on the other side includes: filling the gap on the other side of the capillary and the transition block with brazing material, and sending the capillary and the transition block into a vacuum furnace for vacuum brazing.

[0011] In some embodiments of the present application, filling the gap between the capillary and the other side of the transition block with solder includes: filling the gap between the capillary and the other side of the transition block with solder according to solder filling requirements.

[0012] In some embodiments of the present application, the solder filling requirements include: uniform coating of the solder, with a thickness of the coated solder being less than or equal to 1.5 mm.

[0013] In some embodiments of the present application, sending the capillary and the transition block into a vacuum furnace for vacuum brazing includes: sending the capillary and the transition block into a vacuum furnace for vacuum brazing, the vacuum brazing includes a heating process and a cooling process, and the vacuum degree of the vacuum furnace is set to 10Pa-4Pa.

[0014] In some embodiments of the present application, the temperature rising process includes multiple temperature rising sub-processes, and a temperature keeping process is provided between adjacent temperature rising sub-processes.

[0015] In some embodiments of the present application, the cooling process includes multiple cooling sub-processes.

[0016] Based on the above solution, this application has at least the following advantages or improvements:

[0017] In the technical solutions provided in some embodiments of the present application, laser welding is performed on the gap on one side of the capillary and the transition block; after the laser welding is completed, vacuum brazing is performed on the gap on the other side. In the present application, by using different welding methods on both sides of the pressure tube structure, the capillary and the transition block are welded to form a pressure measuring component, thereby overcoming the disadvantage that the vacuum furnace will limit the overall size of the engine; the laser welding technology has the advantages of concentrated energy, low heat input, and small heat-affected zone, which reduces the welding deformation of the thin-walled capillary and forms a reliable connection at the bottom of the connection between the capillary and the transition block, overcoming the defect of the sudden drop in high-temperature performance of vacuum brazing; vacuum brazing is used to strengthen the strength of the weld joint in batches, increase the effective penetration depth of the weld, and form a reliable connection that can meet the working conditions of the supersonic ramjet engine.

[0018] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0020] Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0021] In the attached figure:

[0022] Figure 1 A flow chart showing a method for welding a pressure measuring tube according to one embodiment of the present application is shown;

[0023] Figure 2 A flow chart showing a method for welding a pressure measuring tube according to one embodiment of the present application is shown;

[0024] Figure 3 A schematic diagram of laser welding according to an embodiment of the present application is shown;

[0025] Figure 4 A simplified diagram of a pressure measuring tube weld according to one embodiment of the present application is shown;

[0026] Figure 5 A schematic diagram of solder filling according to an embodiment of the present application is shown;

[0027] Figure 6 A schematic diagram of weld formation according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0028] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art.

[0029] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0030] It should be noted that the term "plurality" used in this document refers to two or more. "And / or" describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. The character " / " generally indicates an "or" relationship between the associated objects.

[0031] The following is a detailed description of the implementation details of the technical solution of the embodiment of the present application:

[0032] See also Figure 1 .

[0033] Figure 1 A flow chart of a method for welding a pressure measuring tube according to an embodiment of the present application is shown, wherein the pressure measuring tube includes a capillary tube and a transition block, as shown in FIG. Figure 1 As shown, the method may include steps S101-S102:

[0034] Step S101 : performing laser welding on the gap between the capillary tube and one side of the transition block.

[0035] Step S102: After the laser welding is completed, vacuum brazing is performed on the gap on the other side.

[0036] In the present application, laser welding can be performed on the gap on one side of the capillary and the transition block; after completing the laser welding, vacuum brazing can be performed on the gap on the other side. In the present application, by using different welding methods on both sides of the pressure tube structure, the capillary and the transition block are welded to form a pressure measuring component, thereby overcoming the disadvantage that the vacuum furnace will limit the overall size of the engine; the laser welding technology has the advantages of concentrated energy, low heat input, and small heat-affected zone, which reduces the welding deformation of the thin-walled capillary and forms a reliable connection at the bottom of the connection between the capillary and the transition block, overcoming the defect of the sudden drop in high-temperature performance of vacuum brazing; vacuum brazing is used to strengthen the strength of the weld joint in batches, increase the effective penetration depth of the weld, and form a reliable connection that can meet the working conditions of the supersonic ramjet engine.

[0037] See also Figure 2 .

[0038] Figure 2 FIG. 1 shows a flow chart of a method for welding a pressure measuring tube according to an embodiment of the present application. Figure 2 As shown, the laser welding method may include steps S201-S203:

[0039] Step S201: setting the welding parameters of the laser welding equipment to first welding parameters, and determining the laser welding path according to the structure of the pressure measuring tube.

[0040] Step S202, performing at least one point welding in a protective gas environment according to the first welding parameters and the laser welding path;

[0041] Step S203: adjusting the welding parameters of the laser welding equipment to second welding parameters, and performing continuous welding in the protective gas environment according to the second welding parameters and the laser welding path.

[0042] In the present application, the welding parameters of the laser welding equipment are set as the first welding parameters, including: the laser power can be set to 100W to 300W, the welding speed can be set to 1200mm / min to 2000mm / min, and the defocus amount can be set to -5mm to +5mm.

[0043] In this application, the laser welding equipment's welding parameters are referred to as second welding parameters, including: laser power can be set to 800W to 2500W, welding speed can be set to 1200mm / min to 2000mm / min, and defocus can be set to -5mm to +5mm. When laser welding reaches arc closure, the laser power can be reduced to 400W to 600W.

[0044] In the present application, laser welding can be performed in an environment where argon is used as a shielding gas. After laser welding is completed, argon gas can be maintained for more than 3 seconds to reduce the oxidation tendency of the weld after welding.

[0045] In the present application, the vacuum brazing for the other side gap includes: filling the other side gap between the capillary and the transition block with brazing material, and sending the capillary and the transition block into a vacuum furnace for vacuum brazing.

[0046] In this application, the filling of solder needs to meet certain solder filling requirements. For example, the solder should be evenly coated on the welded part. The solder thickness of the solder coating should not exceed 1.5 mm for a soldering seam with a length of 20 mm and a gap of less than 0.2 mm. The solder outside the gap of 2 mm needs to be scraped off and cleaned to remove excess solder and avoid solder accumulation.

[0047] In the present application, the method of sending the capillary tube and the transition block together into a vacuum furnace for vacuum brazing may include: sending the capillary tube and the transition block together into a vacuum furnace for vacuum brazing, wherein the vacuum brazing includes a heating process and a cooling process, and the vacuum degree of the vacuum furnace is set to 10Pa-4Pa. The heating process includes multiple heating sub-processes, and a heat preservation process is provided between adjacent heating sub-processes. The cooling process includes multiple cooling sub-processes.

[0048] For example, the temperature change process of the entire vacuum brazing can be as follows: enter the furnace at room temperature, heat from room temperature to 500℃, the heating rate is 450℃ / h, and keep warm for 20 minutes; heat from 500℃ to 850℃, the heating rate is 300℃ / h, and keep warm for 20 minutes; heat from 850℃ to 1020℃, the heating rate is 300℃ / h; at 1020℃, keep warm for 30 minutes; cool from 1020℃ to 650℃, 90℃ / h~100℃ / h; cool from 650℃ to 40℃, and cool with the furnace until it drops to room temperature from 40℃.

[0049] In order to enable those skilled in the art to have a deeper understanding of the present application, a complete embodiment will be described below.

[0050] Example 1

[0051] This embodiment uses the welding of a transition block made of GH3625 and a capillary made of 12Cr18Ni9 as an example, including the entire process of pre-welding preparation, laser welding and vacuum brazing.

[0052] Preparation before welding:

[0053] (1) Remove impurities and oil stains on the surface of the transition block and capillary, that is, remove hydrogen through acid washing (ultrasonic cleaning can be added);

[0054] (2) Send the transition block and capillary tube processed in step (1) to the welding site for standby use. Before welding, clean the welding position with anhydrous ethanol and dry it with a hair dryer;

[0055] See also Figure 3 , Figure 3 A schematic diagram of laser welding according to an embodiment of the present application is shown.

[0056] (3) Assemble the transition block and capillary to be welded in step (2) into a pressure measuring tube 3, and Figure 3 The welding shown requires plugging and fixing it upside down on the laser welding work platform 5; by adjusting the shim 4, the bottom surface of the pressure measuring tube 3 is level with the laser welding work platform 5, and the shim 4 is locked to fix it.

[0057] Laser welding:

[0058] (4) Adjust the first welding parameters: laser power: 200W, welding speed 1200mm / min, defocusing amount +2, argon protection, focus the laser on the weld, draw the motion trajectory required for the laser welding path, determine the welding starting point, confirm that the shielding gas is in the ventilation state, and start teaching;

[0059] (5) Adjust the second welding parameters: laser power: 1000W, welding speed 1200mm / min, defocusing amount +2, argon protection, continuous welding procedure, laser power attenuation to 400~600W at the end of welding arc; focus the laser on the weld, draw the motion trajectory required for the laser welding path, determine the welding starting point, confirm that the shielding gas is in the ventilation state, and start continuous welding.

[0060] See also Figure 4 , Figure 4 A simplified diagram of a pressure measuring tube weld according to an embodiment of the present application is shown. Figure 4 As shown, after the laser welding is completed, the capillary tube and the gap on one side of the transition block are connected by laser welding.

[0061] Vacuum brazing:

[0062] (6) Fill the gap between the capillary and the transition block that have been continuously welded in step (5) with nickel-chromium-silicon-boron solder HBNi82CrSiB. Figure 5 , Figure 5 A schematic diagram of solder filling according to an embodiment of the present application is shown. Figure 5 As shown, the coating solder has a thickness of 1.5 mm and a width of 1 mm.

[0063] (7) Sending the pressure measuring tube filled with solder in step (6) into a vacuum furnace for vacuum brazing:

[0064] Brazing furnace vacuum degree: 10-4Pa;

[0065] Heating process: put into the furnace at room temperature, room temperature ~ 500℃, 450℃ / h, keep warm for 20min; 500℃ ~ 850℃, 300℃ / h, keep warm for 20min; 850℃ ~ 1020℃, 300℃ / h; at 1020℃, keep warm for 30min;

[0066] Cooling process: 1020℃~650℃, 90℃ / h~100℃ / h; 650℃~40℃, cool with the furnace; 40℃~room temperature, turn off the vacuum pump, and take out of the furnace at room temperature.

[0067] (9) Take the cooled pressure tube out of the vacuum furnace. Figure 6 , Figure 6A schematic diagram of weld formation according to an embodiment of the present application is shown. Figure 6 As shown, laser welding and vacuum brazing are used on both sides of the pressure gauge tube respectively. The brazing material is heated in a vacuum furnace and filled in the direction of the laser weld, which can effectively fill the position where the laser weld cannot extend and greatly improve the stability of the structural connection.

[0068] In summary, the application proposes to use a hybrid welding technology of laser welding and vacuum brazing to connect the capillary and the transition block to form a pressure measuring component, thereby overcoming the disadvantage that the vacuum furnace will limit the overall size of the engine; utilizing the advantages of laser welding technology such as concentrated energy, low heat input, and small heat-affected zone, reducing the welding deformation of thin-walled capillaries, forming a reliable connection at the bottom of the connection between the capillary and the transition block, and overcoming the defect of a sudden drop in high-temperature performance of vacuum brazing; utilizing vacuum brazing to batch strengthen the strength of the weld joint, increase the effective penetration depth of the weld, and form a reliable connection that can meet the working conditions of the supersonic ramjet engine.

[0069] Those skilled in the art will readily conceive of other embodiments of the present application after considering the specification and practicing the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of this application and include common knowledge or customary techniques in the art that are not disclosed herein.

[0070] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for welding a pressure measuring tube, characterized in that: The pressure measuring tube includes a capillary tube and a transition block, and the method includes: Performing laser welding on the gap between the capillary tube and one side of the transition block; The laser welding comprises: setting a welding parameter of a laser welding device to a first welding parameter, and determining a laser welding path according to the structure of the pressure measuring tube; Performing at least one point welding in a protective gas environment according to the first welding parameters and the laser welding path; Adjusting the welding parameters of the laser welding equipment to second welding parameters, and performing continuous welding in the protective gas environment according to the second welding parameters and the laser welding path; The welding parameters of the laser welding equipment are set to the first welding parameters, including: laser power is set to 100W to 300W, welding speed is set to 1200 mm / min to 2000 mm / min, and defocus is set to -5mm to +5mm; The adjusting the welding parameters of the laser welding equipment to the second welding parameters includes: setting the laser power to 800W to 2500W, setting the welding speed to 1200 mm / min to 2000 mm / min, and setting the defocus amount to -5mm to +5mm; After completing the laser welding, vacuum brazing is performed on the gap on the other side; The vacuum brazing of the gap on the other side includes: filling the gap on the other side of the capillary tube and the transition block with brazing filler metal according to the brazing filler metal filling requirements, and sending the capillary tube and the transition block into a vacuum furnace for vacuum brazing; The solder filling requirements include: uniform solder coating, with a thickness of less than or equal to 1.5 mm; The vacuum brazing includes a heating process and a cooling process, and the vacuum degree of the vacuum furnace is set to 10Pa-4Pa; The heating process includes multiple heating sub-processes, and a heat preservation process is set between adjacent heating sub-processes; The cooling process includes multiple cooling sub-processes.

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