Vacuum electron beam welding method for 3D printing high-temperature alloy and copper dissimilar materials

Abstract

The invention discloses a 3D printing high-temperature alloy and copper dissimilar material vacuum electron beam welding method, and belongs to the technical field of engine turbine pump manufacturing. According to the method, firstly, a copper ring and a high-temperature alloy outer ring printed through 3D printing are assembled, the whole copper ring is located in an inner cavity of the high-temperature alloy outer ring, and the upper end face of the copper ring protrudes out of the upper end face of the high-temperature alloy outer ring; secondly, the assembled component is subjected to demagnetization treatment; and finally, loading the demagnetized assembly into an electron beam welding machine, vacuumizing, and carrying out fusion welding and sealing welding on the upper end and the lower end of the assembly by adopting a vacuum electron beam. According to the method, the reliability and the stability of the welding quality are guaranteed by reasonably determining the assembly clearance, the staggered wall height, the electron beam offset and the welding parameters, and the method has the advantages of being high in practicability and wide in application range.

Description

Technical Field

[0001] The present invention relates to a method for vacuum electron beam welding of dissimilar materials of 3D printed superalloy and copper, belonging to the technical field of manufacturing engine turbo pumps. Background Art

[0002] Among the various combustion components of a liquid rocket engine, the turbo pump, as an important component, operates in a high-speed state and simultaneously withstands high temperature, high pressure, and vibration, etc. Therefore, the reliability of the turbo pump greatly affects the flight performance and safety of the entire rocket.

[0003] The turbo pump mainly consists of two parts: a turbine and a pump. The turbine drives the pump to work through the high-temperature and high-pressure gas generated by the combustion of the gas generator, pressurizes the fuel and oxidizer, and supplies them to the thrust chamber for mixing and combustion to provide power. Since the turbine housing needs to withstand high-temperature and high-pressure gas, it is usually processed using superalloy materials. Moreover, to reduce the friction at the contact part between the turbine housing and the rotor, a copper ring is usually brazed at the contact part between the exhaust housing and the rotor. Before brazing, the ends of the copper ring and the superalloy housing need to be fusion welded and sealed. Since the copper ring and the superalloy housing are dissimilar materials, their physical and chemical properties differ greatly, and the density of the 3D printed superalloy material is relatively poor, making the welding of the two difficult and prone to problems such as brazing leakage at the weld. Summary of the Invention

[0004] The technical problem solved by the present invention is: overcoming the deficiencies of the prior art, a method for vacuum electron beam welding of dissimilar materials of 3D printed superalloy and copper is proposed. By adjusting the assembly gap, misalignment height, electron beam offset amount, and welding parameters between the superalloy outer ring and the copper ring, high-quality vacuum electron beam welding of 3D printed superalloy and copper is effectively achieved.

[0005] The technical solution of the present invention is:

[0006] A method for vacuum electron beam welding of dissimilar materials of 3D printed superalloy and copper, comprising:

[0007] Assemble a copper ring and a superalloy outer ring made by 3D printing. The copper ring is entirely located inside the inner cavity of the superalloy outer ring, the bottom of the copper ring overlaps on the bottom surface of the superalloy outer ring, and the upper end surface of the copper ring protrudes from the upper end surface of the superalloy outer ring;

[0008] Demagnetize the assembled component;

[0009] Install the demagnetized component into an electron beam welding machine, evacuate the air, and then use vacuum electron beam to perform fusion welding and sealing at the upper and lower ends of the component.

[0010] Further, the welding parameters for vacuum electron beam welding are as follows: the working distance between the electron beam welding gun and the demagnetized component is 300 mm ± 5 mm; the focusing current is 1.840 A to 1.910 A; a circular scan with a scanning amplitude of 1.0 mm ± 0.3 mm and a frequency of 300 Hz ± 20 Hz; the welding speed is 0.4 m / min to 0.6 m / min; the electron beam is located at the end butt joint position and biased towards the copper ring, causing the molten metal of the copper ring to flow towards the superalloy side to form an effective deposition.

[0011] Further, when the required penetration depth is 10 mm to 12 mm, the welding beam current is 205 A to 230 A, and the electron beam offset is 0.5 mm to 1.5 mm on the side of the copper ring.

[0012] Further, the misalignment height of the upper end face of the copper ring protruding from the upper end face of the superalloy outer ring is 1 mm ± 0.5 mm.

[0013] Further, the assembly requirement is that the radial assembly clearance is uniform and not greater than 0.1 mm.

[0014] Further, an interference fit between the copper ring and the superalloy outer ring is achieved through cold fitting, with an interference amount of 0.1 mm to 0.2 mm.

[0015] Further, the assembled component is demagnetized, and the residual magnetic flux is not greater than 1 GS.

[0016] Further, the demagnetized component is loaded into an electron beam welding machine for vacuum pumping. The vacuum degree of the welding gun is not greater than 1.3×10 -4 Pa, and the vacuum degree of the welding chamber is not greater than 2.7×10 -2 Pa.

[0017] Further, before assembling the copper ring with the superalloy outer ring made by 3D printing, the surfaces of the copper ring and the superalloy outer ring are cleaned to remove the oxide scale and oil on the surface of the parts to be welded.

[0018] The advantages of the present invention compared with the prior art are as follows:

[0019] (1) For the joints of 3D printed superalloy and copper dissimilar alloys, the present invention determines the welding joint structure and assembly requirements. Under this structure and assembly conditions, the stability of the electron beam welding process of dissimilar materials can be effectively improved, while ensuring the welding quality and avoiding the problem of weld brazing leakage during subsequent brazing.

[0020] (2) For the joint of 3D printed superalloy and copper dissimilar materials, on the premise of high requirement for weld penetration depth, the present invention can achieve one-time welding forming through high-energy electron beam welding, ensuring that the weld penetration depth meets the requirements. And during the actual high-temperature service process, there is no vacuum leakage phenomenon, and the joint quality is good. This welding technology can be extended to the electron beam welding of other superalloys and copper alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0022] Figure 1 is a schematic diagram of the simple structure of the 3D printed superalloy shell in the embodiment of the present invention;

[0023] Figure 2 is a schematic diagram of the copper ring structure in the embodiment of the present invention;

[0024] Figure 3 is a simple schematic diagram of the assembly welding of superalloy and copper ring in the embodiment of the present invention;

[0025] Figure 4 is a flowchart of the method for vacuum electron beam welding of 3D printed superalloy and copper dissimilar materials in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully communicated to those skilled in the art.

[0027] The present invention proposes a method for vacuum electron beam welding of 3D printed superalloy and copper dissimilar materials. In the embodiment, 3D printed GH4169 superalloy is used, and it can also be extended to the electron beam welding of other superalloys and copper alloys.

[0028] The components to be welded are as Figure 1 , Figure 2 shown, the weld penetration depth is 10 - 12 mm, and the specific steps of welding using the method proposed by the present invention are as Figure 4 shown, including:

[0029] (1) Clean the surface of the components to be welded to remove the oxide scale and oil stain on the surface of the welding part.

[0030] (2) Assemble the copper ring with the outer ring of GH4169 superalloy

[0031] High-energy beams are sensitive to the assembly gap. To ensure the welding quality of electron beam welds, during the assembly process, it is required that the radial assembly gap is uniform and not greater than 0.1 mm. Interference fit can also be achieved through cold fitting, with an interference amount of 0.1 - 0.2 mm. At the same time, to ensure effective melting and deposition of the copper-side metal towards the superalloy side during welding, the upper end face of the copper ring should protrude 1 ± 0.5 mm from the upper end face of the superalloy, as Figure 3 shown.

[0032] (3) Demagnetize the assembled components, with the residual magnetic flux not greater than 1 GS.

[0033] (4) Load the product into the electron beam welder and evacuate. The vacuum degree of the welding torch is not greater than 1.3×10 -4 Pa, and the vacuum degree of the welding chamber is not greater than 2.7×10 -2 Pa.

[0034] (5) Adjust the welding parameters and perform vacuum electron beam welding on the copper ring and the outer ring assembly of GH4169 superalloy. Under the conditions of this structure and assembly requirements, to ensure a penetration depth of 10 mm - 12 mm, the welding parameters are as follows: the working distance between the electron beam welding torch and the product is 300 mm ± 5 mm; the focusing current is 1.840 A - 1.910 A; the scanning amplitude is V x = V y = 1.0 mm ± 0.3 mm, circular scanning with a frequency of 300 Hz ± 20 Hz; the welding speed is 0.4 m / min - 0.6 m / min; the welding beam current is 205 A - 230 A; the electron beam offset is 0.5 - 1.5 mm towards the copper side. If the required penetration depth is less than 10 mm, the welding beam current should be adjusted downward accordingly, and the electron beam offset should be reduced.

[0035] After cleaning the parts to be welded in the present invention, assembly, positioning, and demagnetization are carried out, and then the electron beam offset and welding parameters are adjusted for vacuum electron beam welding. Throughout the process, by reasonably determining the assembly gap, misalignment height, electron beam offset, and welding parameters, the reliability and stability of the welding quality are ensured. This method has the characteristics of strong practicability and wide application range.

[0036] The above-described embodiments are only relatively preferred specific implementation manners of the present invention. The ordinary variations and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A vacuum electron beam welding method for dissimilar materials of 3D printed superalloy and copper, characterized in that, Including: Assemble a copper ring with a superalloy outer ring made by 3D printing. The copper ring is entirely located inside the inner cavity of the superalloy outer ring. The bottom of the copper ring is lapped on the bottom surface of the superalloy outer ring, and the upper end surface of the copper ring protrudes from the upper end surface of the superalloy outer ring. Demagnetize the assembled component. Load the demagnetized component into an electron beam welder. After evacuating the air, use vacuum electron beam to perform fusion welding and sealing at the upper and lower ends of the component.

2. The vacuum electron beam welding method for dissimilar materials of 3D printed superalloy and copper according to claim 1, wherein The welding parameters for vacuum electron beam welding are as follows: the working distance between the electron beam welding gun and the demagnetized component is 300mm ± 5mm; the focusing current is 1.840A to 1.910A; the scanning amplitude is a circular scan with an amplitude of 1.0mm ± 0.3mm and a frequency of 300Hz ± 20Hz; the welding speed is 0.4m / min to 0.6m / min; the electron beam is located at the butt joint position of the end and is biased towards the copper ring, so that the molten metal of the copper ring flows towards the superalloy side to form effective deposition.

3. The vacuum electron beam welding method for dissimilar materials of 3D printed superalloy and copper according to claim 2, wherein When the required penetration depth is 10mm to 12mm, the welding beam current is 205A to 230A, and the electron beam offset is 0.5mm to 1.5mm on the copper ring side.

4. The vacuum electron beam welding method for dissimilar materials of 3D printed superalloy and copper according to claim 1, characterized in that The misalignment height of the upper end surface of the copper ring protruding from the upper end surface of the superalloy outer ring is 1mm ± 0.5mm.

5. The vacuum electron beam welding method for dissimilar materials of 3D printed superalloy and copper according to claim 1, characterized in that, The assembly requirement is that the radial assembly clearance is uniform and not greater than 0.1mm.

6. The vacuum electron beam welding method for dissimilar materials of 3D printed superalloy and copper according to claim 1, characterized in that, Realize the interference fit between the copper ring and the superalloy outer ring through cold fitting, and the interference amount is 0.1mm to 0.2mm.

7. The vacuum electron beam welding method for dissimilar materials of 3D printed superalloy and copper according to claim 1, characterized in that, Demagnetize the assembled component, and the residual magnetic flux is not greater than 1GS.

8. The vacuum electron beam welding method for dissimilar materials of 3D printed superalloy and copper according to claim 1, characterized in that, Load the demagnetized component into the electron beam welder and perform vacuum pumping. The vacuum degree of the welding torch shall not be greater than 1.3×10 - 4 Pa, and the vacuum degree of the welding chamber shall not be greater than 2.7×10 -2 Pa.

9. The method for vacuum electron beam welding of dissimilar materials of 3D printed superalloy and copper according to claim 1, characterized in that, Before assembling the copper ring with the superalloy outer ring made by 3D printing, clean the surfaces of the copper ring and the superalloy outer ring to remove the oxide scale and oil stain on the surface of the parts to be welded.

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