A welding method for Monel alloy rotor support

Abstract

This invention discloses a welding method for Monel alloy rotor supports. First, an arc-shaped groove is carved into the support plate to be welded. Then, positioning fixtures are used to ensure the axial and radial dimensions of the support plate and the main shaft during welding. The first support plate is welded using argon arc welding at the bevel of the groove surface, followed by grinding on the reverse side and then grinding on the front side before continuing welding. Argon gas protection is used throughout the process. After stabilizing the weld, carbon dioxide shielded welding is used to create the weld surface before welding the next support plate. Finally, the weld is inspected using dye penetrant testing and ultrasonic testing. This welding method is suitable for welding rotor supports made of low-magnetic Monel alloy materials, avoiding or reducing deformation and fracture caused by welding, preventing a decrease in overall structural strength due to incomplete penetration, and ensuring the accurate dimensions of the welded rotor support.

Description

Technical Field

[0001] This invention belongs to the field of material welding technology and relates to a welding method for a Monel alloy rotor support. Background Technology

[0002] Currently, many electric motors use Monel alloy as the rotor support due to requirements such as low magnetic field design. The main shaft of the rotor support and its supporting square plate are mostly welded. However, welding Monel alloy differs from welding steel. Improper welding procedures can alter the composition of the Monel material, leading to changes in performance, internal defects, fractures, and other damage. Incomplete weld penetration, resulting in holes or seams, reduces structural strength, severely impacting the motor's safety and reliability, and causing significant losses.

[0003] When welding rotor supports using Monel alloy materials, reasonable welding methods and procedures should be adopted. Through a series of welding processes and methods, it is necessary to ensure that the material composition does not change during the welding process and that the structural strength is guaranteed after welding, so as to produce a reliable product. Summary of the Invention

[0004] The purpose of this invention is to provide a welding method for Monel alloy rotor supports. By using methods and measures such as bevel design, tooling design, grinding process, welding time control, and post-weld inspection, the method avoids hole and seam defects in the welding area of ​​Monel alloy, prevents welding-induced fracture, and reduces welding deformation, thereby making the welded Monel alloy structure safe and reliable.

[0005] The technical solution adopted by this invention to solve its technical problem is: a welding method for a Monel alloy rotor support, used for welding a Monel alloy rotor support composed of a main shaft, multiple arc plates, and a supporting square plate, comprising the following steps:

[0006] S1. A circular arc-shaped groove is dug out on the bevel of the support square plate near the main shaft to ensure that the welding can penetrate and avoid defects such as holes and seams, while retaining enough base material to ensure the structural strength of the Monel alloy material.

[0007] S2, Select two semi-circular segmented fixture plates with positioning grooves, connect the connecting plates at both ends of the plates with bolts to form a positioning fixture, place the support square plate to be welded into the positioning groove, insert the spindle into the circular cavity between the two segmented fixture plates, ensure that the support square plate is evenly distributed along the spindle, and press the arc plate tightly against the surface of the segmented fixture plate. In this way, both the arc plate and the support square plate are fixed to the spindle by the positioning fixture, so that the distance between the bevel of the support square plate and the spindle surface is d=2mm. The positioning fixture ensures the axial and radial dimensions of the support square plate and the spindle for welding.

[0008] S3, the first welding step uses argon arc welding to weld the first support square plate on the bevel of the groove surface, and then grinds the reverse side to ensure that the welding material is fully bonded to the support square plate and the spindle material and welds through.

[0009] S4, the second welding pass is performed by grinding on its front side. Then, the same welding wire with the same composition as the base material is used to perform argon arc welding on the support square plate. Argon gas protection is used throughout the process to avoid impurities and porosity, so as to ensure that there are no impurities in the welding process. Argon arc welding is performed alternately on the front and back sides of the groove until a stable weld is formed. Then, carbon dioxide shielded welding is used to make the weld full and strengthen the weld body.

[0010] S5. After the first support plate is welded, the temperature of the spindle welding area should be measured with a temperature gun. After 30 minutes or when the temperature of the main material drops below 50°C, the second support plate can be welded. The welding time of the two support plates should also be strictly controlled to avoid the cumulative heat from the welding of the first support plate reaching the temperature at which the material composition of the spindle changes, causing changes in the material composition and properties. At the same time, a certain amount of natural cooling time can also avoid excessive thermal stress that could lead to significant material deformation or breakage.

[0011] S6. After the last support plate is welded, the weld quality of the support plate and the spindle is checked by dye penetrant testing to see if there are any defects such as holes or seams. Ultrasonic testing is used to check whether the spindle has suffered internal damage due to the high temperature of welding, so as to ensure that the welded structure meets the requirements of safety and reliability.

[0012] The method for welding a Monel alloy rotor bracket has a groove surface with a cross-section of 1 / 4 circular arc, which is tangent to the center line of the supporting square plate, and the radius is 1 / 2 of the thickness of the supporting square plate.

[0013] The method for welding a Monel alloy rotor bracket, wherein the axial height of the segmented tooling plate is 50mm and the radial thickness is 50mm; the axial depth of the positioning groove is 40mm.

[0014] The method for welding a Monel alloy rotor support includes a support plate with semi-circular holes at both ends to release welding stress.

[0015] The beneficial effects of this invention are:

[0016] The welding method of this invention achieves the expected structural strength through process measures such as bevel design, tooling design, grinding process, welding time control, and post-weld inspection; avoids changes in material composition during Monel alloy welding, avoids defects such as holes and seams in the welding area, avoids welding-induced fracture, and reduces welding deformation; the welded Monel alloy structure is safe and reliable.

[0017] This invention's welding method can be used to weld Monel alloy rotor support structures composed of support plates and shafts of various forms and sizes. The positioning fixtures are reusable for batch welding. After welding, the material composition and properties of the Monel structure remain unchanged, resulting in good structural strength and high safety and reliability.

[0018] This invention uses carbon dioxide shielded welding to create the surface, and ensures welding quality and the stability of the spindle's internal materials through process control, weld grinding, welding time control, welding quality inspection methods, weld surface inspection, and internal material inspection. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the Monel alloy rotor support structure of the present invention;

[0020] Figure 2 for Figure 1 A magnified view of part A in the middle;

[0021] Figure 3 This is a schematic diagram of the positioning tooling of the present invention;

[0022] Figure 4 This is a schematic diagram of the overall welding structure of the present invention.

[0023] The labels for each figure are as follows: 11—main shaft, 12—arc plate, 13—support square plate, 14—grooved surface, 21—segmented tooling plate, 22—positioning groove, 23—connecting plate. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings.

[0025] This invention discloses a welding method for Monel alloy rotor supports, applicable to welding Monel alloy rotor support structures composed of arc plates 12, supporting square plates 13, and main shafts 11 of various forms and sizes. The Monel alloy rotor support structure is as follows: Figure 1 As shown. The welding method mainly includes bevel design, tooling design, grinding process, welding time control, and post-weld inspection, and includes the following steps:

[0026] S1, an arc-shaped groove 14 is carved out on the bevel of the support plate 13 near the main shaft 11 to ensure that the welding can penetrate and avoid defects such as holes and seams, while retaining enough base material to ensure the structural strength of the Monel alloy material. Figure 2 As shown, the groove surface 14 has a 1 / 4 circular arc shape, which is tangent to the center line of the supporting square plate 13. The radius is 1 / 2 of the thickness of the supporting square plate 13. The other half of the bevel retains the original bevel shape, while also preserving enough base material to ensure the structural strength of the Monel alloy material.

[0027] S2, select two semi-circular segmented tooling plates 21 with positioning grooves 22, and connect the connecting plates 23 at both ends of them with bolts to form a positioning tooling, such as Figure 3 As shown, the inner diameter of the positioning fixture is the same as that of the main shaft 11. The axial height of the segmented fixture plate 21 is 50mm and the radial thickness is 50mm. The width of the positioning groove 22 is the same as that of the support square plate 13, and the axial groove depth is 40mm. The bolt connection can ensure sufficient constraint force and reuse. The support square plate 13 to be welded is placed in the positioning groove 22, and the main shaft 11 is inserted into the circular cavity between the two segmented fixture plates 21 to ensure that the support square plate 13 is evenly distributed along the position of the main shaft 11 and to reduce the deformation caused by welding. The arc plate 12 is tightly attached to the surface of the segmented fixture plate 21. In this way, the arc plate 12 and the support square plate 13 are both fixed to the main shaft 11 by the positioning fixture, so that the distance d between the bevel of the support square plate 13 and the surface of the main shaft 11 is 2mm. The special positioning fixture design ensures the axial and radial dimensions of the welding between the support square plate 13 and the main shaft 11.

[0028] This step uses a positioning fixture to determine the axial and radial dimensions. Based on the normal butt welding bevel, an asymmetrical bevel design is used for welding. The uniquely designed groove surface 14 ensures a good bond between the base material and the welding area.

[0029] S3, the first weld is performed using argon arc welding on the bevel of the groove surface 14 to weld the first support square plate 13, and the reverse side is ground to ensure that the welding material is fully bonded to the materials of the support square plate 13 and the main shaft 11 and penetrates completely. The first weld of the argon arc welding root pass is ground on the reverse side to ensure that the base material is fully penetrated, so that the welding material is fully bonded to the materials of the support square plate 13 and the main shaft 11, and to avoid seams and holes appearing inside the welded body.

[0030] In this step, the support plate 13 has semi-circular holes at both ends to release welding stress. The support plate 13 is inserted into the positioning groove 22. The axial positioning, circumferential angle positioning and radial clearance positioning of the support plate 13 and the spindle 11 are determined by the position of the groove, so as to ensure the welding position accuracy of the support plate 13. The support plate 13 is welded at spatial intervals to avoid heat concentration in a certain area of ​​the spindle 11.

[0031] S4. The second welding pass involves grinding the front side of the plate and continuing to use welding wire with the same composition as the base material for argon arc welding of the support square plate 13. Argon gas protection is used throughout the process to avoid impurities and porosity, ensuring that the welding process is free of impurities. After completing the argon arc welding root pass on both sides, argon arc welding is performed alternately on the front and back sides of the groove surface 14 until a stable weld is formed. Then, carbon dioxide shielded welding is used to create the surface, making the weld full and strengthening the weld body.

[0032] S5. After the first support plate 13 is welded, the temperature of the welding area of ​​the spindle 11 should be measured with a temperature gun. After 30 minutes or when the temperature of the main material drops to below 50°C, the second support plate 13 should be welded. The welding time of the two support plates 13 should also be strictly controlled to avoid the cumulative welding heat of the first support plate 13 reaching the temperature at which the material composition of the spindle 11 changes, causing changes in the material composition and properties of the spindle 11. At the same time, a certain amount of natural cooling time can also avoid excessive thermal stress that could lead to significant deformation or breakage of the material.

[0033] S6, such as Figure 4 As shown, after the last support plate 13 is welded, the weld quality of the support plate 13 and the spindle 11 is checked by dye penetrant testing to see if there are any defects such as holes and seams. Ultrasonic testing is used to check whether the spindle 11 has suffered internal damage due to the high temperature of welding, so as to ensure that the welded structure meets the requirements of safety and reliability.

[0034] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some of the application examples. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method for welding a Monel alloy rotor support, used for welding a Monel alloy rotor support composed of a main shaft (11), multiple arc plates (12), and a supporting square plate (13), characterized in that: Includes the following steps S1, a circular arc-shaped groove (14) is dug out on the bevel of the support plate (13) near the main shaft (11). S2, select two semi-circular segmented tooling plates (21) with positioning grooves (22), connect the connecting plates (23) at both ends of them with bolts to form a positioning tooling, place the support square plate (13) into the positioning groove (22), insert the main shaft (11) into the cavity between the two segmented tooling plates (21), ensure that the support square plate (13) is evenly distributed along the position of the main shaft (11), and press the arc plate (12) tightly against the surface of the segmented tooling plate (21) so that the distance between the bevel of the support square plate (13) and the main shaft (11) is d=2mm; S3, use argon arc welding to weld the first support square plate (13) at the bevel of the groove surface (14), and grind it on the reverse side to ensure that the welding material is fully combined with the support square plate (13) and the main shaft (11) and welded through. S4, grind its front side, continue to use argon arc welding to weld the support square plate (13), argon gas protection throughout the process, argon arc welding alternately welds on the front and back sides of the groove surface (14) until a stable weld is formed, then use carbon dioxide shielded welding to make the weld full overall. S5. After the first support square plate (13) is welded, the temperature of the welding area is measured with a temperature measuring gun. After 30 minutes or when the temperature drops to within 50°C, the next support square plate (13) is welded. S6. After the last support plate (13) is welded, the quality of the welded body of the support plate (13) and the spindle (11) is checked by dye penetrant testing to see if there are any defects such as holes and seams. The spindle (11) is checked by ultrasonic testing to see if it has been internally damaged due to the high temperature of welding.

2. The welding method for a Monel alloy rotor support according to claim 1, characterized in that, The groove surface (14) has a cross-section of 1 / 4 circular arc, which is tangent to the center line of the supporting square plate (13), and the radius is 1 / 2 of the thickness of the supporting square plate (13).

3. The welding method for a Monel alloy rotor support according to claim 2, characterized in that, The segmented tooling plate (21) has an axial height of 50 mm and a radial thickness of 50 mm; the positioning groove (22) has an axial groove depth of 40 mm.

4. The welding method for a Monel alloy rotor support according to claim 2, characterized in that, The supporting square plate (13) has semi-circular holes at both ends.

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