Vacuum electron beam welding method for a heterogeneous metal electromagnet blank

Abstract

The application discloses a vacuum electron beam welding method of a heterogeneous metal electromagnet blank, and the sleeve ring, the magnetic conducting ring, the magnetic shielding ring and the stop iron are assembled into an integrated whole through design of a welding mandrel and a welding clamp, three welding seams are designed, and welding of each component is completed by adopting different welding sequences; the scheme ensures that there are no defects such as cracks and incomplete fusion in the welding seam of the heterogeneous metal electromagnet blank, meets the requirements of a first-grade welding seam of a relevant standard, simultaneously improves the welding deformation of the electromagnet blank, and ensures that the coaxiality of the electromagnet blank after welding meets the subsequent machining requirements.

Description

Technical Field

[0001] This invention relates to the field of metal welding, and specifically to a vacuum electron beam welding method for dissimilar metal electromagnet blanks. Background Technology

[0002] With the continuous development of aerospace engineering, spacecraft propellants are increasingly adopting cryogenic propellants, such as liquid hydrogen and liquid oxygen or aerospace kerosene and liquid oxygen. With the use of cryogenic propellants, solenoid valves, due to their advantages of simple operation, sensitive action, small size, high thrust, reliable performance, and ease of computer connection, have gradually become the mainstream valve in the propulsion systems of new spacecraft. A solenoid valve typically consists of components such as a coil frame, coil, armature, and valve body. The valve is normally closed (open). When the electromagnet is energized, the coil generates a magnetic field, causing the valve core to displace under the electromagnetic attraction, overcoming the spring force, thus opening (closing) the solenoid valve. After de-energization, the valve core returns to its original position under the spring force, and the solenoid valve closes.

[0003] As the core component of a solenoid valve, the electromagnet's material properties and machining precision have a decisive impact on the valve's performance. An electromagnet is typically manufactured by welding a collar (made of soft magnetic alloy 1J50), a magnetic guide ring (made of high-temperature alloy GH1140), a magnetic isolation ring (made of soft magnetic alloy 1J50), and a stop (made of high-temperature alloy GH1140) sequentially to form an electromagnet blank, which is then machined. Both soft magnetic alloy 1J50 and high-temperature alloy GH1140 are high-melting-point refractory metals. Introducing vacuum electron beam welding into the welding of dissimilar high-temperature metals utilizes its concentrated heat input and strong penetration to ensure a certain weld penetration depth and increase weld strength. However, the two materials have significant differences in physical properties, chemical properties, and chemical composition. During welding, the uneven shrinkage of the weld pool during solidification generates significant internal stress at the joint, making vacuum electron beam welding of dissimilar materials like soft magnetic alloy 1J50 and high-temperature alloy GH4169 prone to cracking. Furthermore, while the overall size of the electromagnet blank is small, the number of welds is relatively large. After multiple welds are completed, the electromagnet blank undergoes significant deformation, and its coaxiality cannot meet the requirements of subsequent machining. Summary of the Invention

[0004] The purpose of this invention is to provide a vacuum electron beam welding method to ensure that the weld seam of a metal electromagnet blank is free of defects such as cracks and lack of fusion, thus meeting the weld seam requirements. At the same time, it improves the welding deformation of the electromagnet blank and ensures that the coaxiality of the electromagnet blank after welding meets the requirements of subsequent machining.

[0005] The solution of the present invention:

[0006] A vacuum electron beam welding method for dissimilar metal electromagnet blanks includes the following steps:

[0007] S1: Clean the collar, magnetic ring, magnetic shielding ring, stop iron, welding mandrel, and welding fixture with alcohol, blow them dry with compressed air, and dry them in an environment of 60±10℃;

[0008] S2: Using a welding mandrel and welding fixture, the collar, magnetic ring, magnetic shielding ring and stop are assembled in sequence into an electromagnet blank in the state to be welded;

[0009] S3: Set the vacuum electron beam welding parameters and weld the welds between the collar and the magnetic ring, the magnetic ring and the magnetic isolation ring, and the magnetic isolation ring and the stop. The welding method steps are as follows:

[0010] S31: Place the electromagnet blank in a vacuum environment to be welded;

[0011] S32: With the stationary rotating shaft as the zero point, weld the weld between the magnetic shielding ring and the stop iron in a clockwise direction. After welding is completed, the rotating shaft returns to zero.

[0012] S33: Weld the weld between the collar and the magnetic ring in a clockwise direction. After welding, return the rotating shaft to zero and keep it warm for a period of time after welding.

[0013] S34: Open the vacuum environment to release pressure and cool to room temperature;

[0014] S35: Close the vacuum environment, weld the weld between the magnetic ring and the magnetic isolation ring in a counterclockwise direction, keep it warm for a period of time after welding, release the pressure, and the welding is complete;

[0015] Among them: the collar and the magnetic shielding ring are made of soft magnetic alloy 1J50 material, and the magnetic guide ring and the stop iron are made of high temperature alloy GH1140 material.

[0016] In this technical solution, the vacuum environment is no greater than pa.

[0017] In this technical solution, each weld seam is kept warm for at least 10 minutes after welding in a vacuum environment.

[0018] In this technical solution, the electron beam currents during welding of the three weld seams are different.

[0019] In this technical solution, the electron beam current is largest when welding the collar and the magnetic ring, and smallest when welding the magnetic ring and the magnetic shielding ring.

[0020] In this technical solution, during the execution of step S34, the welding equipment and the electromagnet blank cannot be separated, and the zero position of the rotating shaft cannot be adjusted.

[0021] In this technical solution, the welding mandrel is coaxially arranged inside the collar, the magnetic guide ring, and the magnetic isolation ring. One end of the stop is coaxially arranged inside the magnetic isolation ring, and the other end of the stop is arranged on the welding fixture, which is located inside the electron beam welding machine.

[0022] In this technical solution, the relative position between the electron beam welder and the welding mandrel remains unchanged, while the welding mandrel rotates during welding.

[0023] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0024] (1) This invention clarifies the different weld joint dimensions corresponding to three different weld penetration requirements when electron beam welding dissimilar metal lock-bottom joints of soft magnetic alloy 1J50 and high-temperature alloy GH1140. The joint dimensions can effectively ensure that the internal quality of the weld meets the relevant requirements of Class I welds in GJB1718A-2005 "Electron Beam Welding".

[0025] (2) This invention designs a brass material for the assembly and welding fixture of vacuum electron beam welding of dissimilar metal electromagnet blanks made of soft magnetic alloy 1J50 and high-temperature alloy GH1140. This assembly and welding fixture can improve the coaxiality of the electromagnet blank before welding, and control the deformation of the welded parts by physical limiting and accelerating heat dissipation, thereby improving the coaxiality of the product after welding. At the same time, this fixture can facilitate the assembly of parts, protect the outer surface quality of the stop end, and prevent the product from being scratched.

[0026] (3) This invention clarifies the welding parameters (including: accelerating voltage, focusing current, beam current, welding speed, scanning waveform, scanning amplitude, vacuum degree, welding beam initiation angle, welding angle, and beam extinguishing angle) corresponding to different welding joints when electron beam welding of dissimilar metal lock bottom joints of soft magnetic alloy 1J50 and high temperature alloy GH1140, for three different weld penetration requirements. The above welding parameters can effectively ensure that the internal quality of the weld meets the relevant requirements of Class I weld in GJB1718A-2005 Electron Beam Welding.

[0027] (4) This invention designs a welding sequence for vacuum electron beam welding of electromagnet blanks with three weld seams. By using different welding sequences and cooling the workpiece during the welding process, the deformation of the welded parts can be effectively controlled, and the coaxiality of the product after welding can be improved. Attached Figure Description

[0028] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0029] Figure 1 This is a schematic diagram of the structure of an electromagnet blank;

[0030] Figure 2 This is a schematic diagram of the electromagnet blank after clamping.

[0031] Figure 3 This is a structural diagram of the weld;

[0032] Figure 4 This is a schematic diagram of the lap joint lock bottom joint structure of the weld;

[0033] Figure 5 This is a schematic diagram showing the depth dimensions of the weld.

[0034] Wherein: 1 is the collar; 2 is the magnetic guide ring; 3 is the magnetic shielding ring; 4 is the stop; 5 is the welding mandrel; 6 is the welding fixture; A is the first weld; B is the second weld; and C is the third weld. Detailed Implementation

[0035] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0036] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features for a similar purpose, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0037] like Figure 1 As shown, the welding objects in this embodiment are: a collar (made of soft magnetic alloy 1J50), a magnetic guide ring (made of high temperature alloy GH1140), a magnetic shielding ring (made of soft magnetic alloy 1J50), and a stop (made of high temperature alloy GH1140). The four components are assembled and welded together using an overlapping and locking structure.

[0038] like Figure 4 and Figure 5 The blank in this embodiment is designed with three weld seams. At the first weld seam, the joint lap thickness *a* is 4.5 mm, the lock base width *b* is 2 mm, the lock base thickness *c* is 2.5 mm, and the weld penetration depth *h* is required to be ≥ 4.5 mm. At the second weld seam, the joint lap thickness *a* is 4 mm, the lock base width *b* is 2 mm, the lock base thickness *c* is 2.5 mm, and the weld penetration depth *h* is required to be ≥ 4 mm. At the third weld seam, the joint lap thickness *a* is 3.5 mm, the lock base width *b* is 2.5 mm, the lock base thickness *c* is 16 mm, and the weld penetration depth *h* is required to be ≥ 3.5 mm.

[0039] The first weld A refers to the connection between the collar and the magnetic guide ring; the second weld B refers to the connection between the magnetic guide ring and the magnetic isolation ring; and the third weld C refers to the connection between the magnetic isolation ring and the stop.

[0040] like Figure 2 As shown, this embodiment is designed with a welding mandrel and welding fixture for assembling and welding the electromagnet blank.

[0041] During use, the collar, magnetic guide ring, magnetic shielding ring, and stop are inserted sequentially from the small diameter end of the welding mandrel and assembled in that order. After assembly, the stop is inserted into the recess of the welding fixture. During welding, the welding fixture is clamped at the chuck end of the electron beam welding machine, and the tail end is pressed tightly against the tail end hole of the welding mandrel, thus completing the pre-welding assembly.

[0042] The welding mandrel is made of brass and is installed on the back of the weld. Its functions are: first, to improve the coaxiality of the electromagnet blank before welding; second, to control the deformation of the weldment during the welding process; and third, to accelerate heat dissipation, which also helps to control the deformation of the weldment. The welding fixture is also made of brass. Its function is to facilitate the assembly of parts and protect the outer surface of the stop end from being scratched.

[0043] Welding includes three preparation steps, specifically:

[0044] Pre-welding cleaning and drying: When welding electromagnet blanks, first clean the collar, magnetic ring, magnetic shielding ring, stop iron, welding mandrel, and welding fixture with alcohol and then dry them with compressed air. Then dry them at a temperature of 60±10℃ for no less than 30 minutes to ensure that the weld seam is free of defects such as inclusions and porosity due to unclean parts.

[0045] Pre-welding assembly: Using assembly and welding fixtures, assemble the collar, magnetic guide ring, magnetic shielding ring, and stop iron into an electromagnet blank in a state ready for welding, ensuring that the misalignment of the joint position is ≤0.07mm.

[0046] Welding parameters: Vacuum electron beam welding parameters include accelerating voltage, focusing current, beam current, welding speed, scanning waveform, scanning amplitude, vacuum level, welding beam initiation angle, welding angle, and beam extinguishing angle. For the three weld seams of an electromagnet blank, appropriate welding parameters can reduce the internal stress generated by the solidification of the weld seam due to differences in the physical and chemical properties of the two materials, thus preventing internal cracks in the weld seam. The vacuum electron beam welding parameters for an electromagnet blank are as follows.

[0047]

[0048] The specific welding sequence is as follows:

[0049] Step 1: Send the assembled electromagnet blank into the vacuum chamber, evacuate the vacuum chamber, and prepare to start welding the product once the vacuum level meets the welding parameter requirements.

[0050] Step 2: When the vacuum level reaches the welding requirement of ≤5×10-2Pa, return the X, Y, and C axes to zero, align the lower point of the electron beam with the third weld seam, and weld in a clockwise direction. After welding is completed, rotate the C axis back to zero.

[0051] Step 3: After the third weld is completed, align the lower point of the electron beam with the first weld and weld in a clockwise direction. After welding, rotate the C-axis back to zero and keep it warm for 10 minutes after welding.

[0052] Step 4: Depressurize the electron beam welding machine and open the vacuum chamber until the electromagnet blank cools to room temperature. When performing this process, do not remove the workpiece from the electron beam welding machine, and do not adjust the zero position of the C-axis.

[0053] Step 5: Close the vacuum chamber door and evacuate the vacuum. Once the vacuum level reaches the welding requirement of ≤5×10-2Pa, align the lower electron beam point with the second weld seam and weld in a counterclockwise direction. After welding, maintain the temperature for 10 minutes, then depressurize and remove the workpiece.

[0054] After welding is completed, the workpiece is removed, and samples are taken from the welded workpiece for verification.

[0055] After welding, the coaxiality of the electromagnet blank was measured, and the result was 0.07 mm, meeting the requirements for subsequent precision machining. Four sections were cut from each of the three weld seams, and metallographic examination was performed on the cut surfaces. The first weld seam showed no cracks, lack of fusion, porosity, or inclusions in any of the four sections, and the internal quality of the weld met the requirements for Class I welds in GJB1718A-2005. The weld penetration depths were 5.1 mm, 4.9 mm, 4.8 mm, and 4.9 mm, respectively. The second weld seam also showed no cracks, lack of fusion, porosity, or inclusions in any of the four sections, and the internal quality of the weld met the requirements of GJB1718A-2005. According to the Class I weld requirements in 718A-2005, the weld penetration depths are 4.3mm, 4.3mm, 4.0mm, and 4.1mm respectively. Metallographic examination of the four sections of weld #3 showed no cracks, lack of fusion, porosity, or inclusions. The internal quality of the weld meets the Class I weld requirements in GJB1718A-2005, with weld penetration depths of 3.9mm, 3.9mm, 3.8mm, and 3.8mm respectively. In summary, the internal quality and weld penetration depth of all welds meet the requirements.

[0056] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A vacuum electron beam welding method for dissimilar metal electromagnet blanks, characterized in that... Includes the following steps: S1: Clean the collar, magnetic ring, magnetic shielding ring, stop iron, welding mandrel, and welding fixture with alcohol, blow them dry with compressed air, and dry them in an environment of 60±10℃; S2: Using a welding mandrel and welding fixture, the collar, magnetic ring, magnetic shielding ring and stop are assembled in sequence into an electromagnet blank in the state to be welded; S3: Set the vacuum electron beam welding parameters and weld the welds between the collar and the magnetic ring, the magnetic ring and the magnetic isolation ring, and the magnetic isolation ring and the stop. The welding method steps are as follows: S31: Place the electromagnet blank in a vacuum environment to be welded; S32: With the stationary rotating shaft as the zero point, weld the weld between the magnetic shielding ring and the stop iron in a clockwise direction. After welding is completed, the rotating shaft returns to zero. S33: Weld the weld between the collar and the magnetic ring in a clockwise direction. After welding, return the rotating shaft to zero and keep it warm for a period of time after welding. S34: Open the vacuum environment to release pressure and cool to room temperature; S35: Close the vacuum environment, weld the weld between the magnetic ring and the magnetic isolation ring in a counterclockwise direction, keep it warm for a period of time after welding, release the pressure, and the welding is complete; Among them: the collar and the magnetic shielding ring are made of soft magnetic alloy 1J50 material, and the magnetic guide ring and the stop iron are made of high temperature alloy GH1140 material.

2. The vacuum electron beam welding method for dissimilar metal electromagnet blanks according to claim 1, characterized in that... The vacuum environment is no greater than pa.

3. The vacuum electron beam welding method for dissimilar metal electromagnet blanks according to claim 2, characterized in that... Each weld should be kept warm for at least 10 minutes after welding in a vacuum environment.

4. The vacuum electron beam welding method for dissimilar metal electromagnet blanks according to claim 1, characterized in that... The electron beam currents at the three weld seams were different.

5. The vacuum electron beam welding method for dissimilar metal electromagnet blanks according to claim 4, characterized in that... The electron beam current is greatest when the welding collar and the magnetic ring are joined, and smallest when the welding magnetic ring and the magnetic shielding ring are joined.

6. The vacuum electron beam welding method for dissimilar metal electromagnet blanks according to claim 1, characterized in that... During step S34, the welding equipment and the electromagnet blank cannot be separated, and the zero position of the rotating shaft cannot be adjusted.

7. A vacuum electron beam welding method for dissimilar metal electromagnet blanks according to any one of claims 1-6, characterized in that: The welding mandrel is coaxially set inside the collar, the magnetic guide ring, and the magnetic shielding ring. One end of the stop is coaxially set inside the magnetic shielding ring, and the other end of the stop is set on the welding fixture, which is located inside the electron beam welding machine.

8. The vacuum electron beam welding method for dissimilar metal electromagnet blanks according to claim 1, characterized in that... The relative position between the electron beam welder and the welding mandrel remains unchanged, while the welding mandrel rotates during welding.

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