A process for welding a cylindrical part to a sheet metal part

Abstract

This invention discloses a process for welding a cylindrical part to a sheet metal part, comprising the following steps: S1, preparing a Z-shaped sheet metal part, and opening an annular groove on the upper surface of the first platform of the Z-shaped sheet metal part; S2, opening a first chamfer on the outer edge of the annular groove of the Z-shaped sheet metal part, and simultaneously opening a second chamfer on the outer edge of the bottom contact surface of the cylindrical part; S3, performing surface treatment on the Z-shaped sheet metal part and the cylindrical part, followed by preheating at a temperature of 120-150°C; S4, coating a material layer on the annular groove of the Z-shaped sheet metal part and the contact surface of the cylindrical part, and then embedding the cylindrical part into the annular groove and welding it in place using laser welding; S5, filling the inner and outer connection points of the cylindrical part and the Z-shaped sheet metal part with Sn welding material, and performing Sn welding. This application achieves effective fixation and provides space for Sn welding material by precisely designing the matching between the annular groove of the Z-shaped sheet metal part and the cylindrical part, thereby improving the stability and reliability of the welded structure.

Description

Technical Field

[0001] This invention belongs to the field of metal sheet welding technology, specifically relating to a process for welding cylindrical parts to sheet metal parts. Background Technology

[0002] Shafts are common rotating parts in electric motors, serving to support and transmit torque. The design and manufacturing quality of shafts directly impact the motor's performance and lifespan. They are typically used at the ends of motors to fix and connect other components. However, there are bottlenecks in the connection process for shafts, making it difficult to guarantee strength and dimensional stability. While molecular diffusion welding can form a connection, the excessive welding pressure, including the weight of the welding machine, can easily cause product deformation; furthermore, the parallelism of the product surface is unstable during welding, compromising dimensional quality. Given that the pull-out strength requirements for these products are relatively relaxed, greater emphasis is placed on a stable connection in the axial direction to fully guarantee the overall fixation performance of the product.

[0003] Traditional welding methods use Ag-based solder molecular diffusion welding. This silver-based solder has a relatively high melting point and is suitable for applications that require welding at higher temperatures.

[0004] Chinese patent application publication number CN111774940A discloses a metal sheet welding process. The grinding equipment used in this process includes a support frame, on which a motor is mounted. A grinding roller is fixedly connected to the end of the motor's output shaft. A support platform is fixedly connected to the support frame at the bottom of the grinding roller, and a cylindrical groove is opened on the top of the support platform. This method uses a push rod that can be pushed by a hydraulic rod connected to the bottom of the worktable. However, in actual use, after the above welding method is completed, it is easy to fall off, the firmness is not strong, and the application scenarios of the welded product are limited. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a process for welding cylindrical parts and sheet metal parts, thereby solving the above-mentioned technical problems existing in the prior art.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A process for welding a cylindrical part to a sheet metal part includes the following steps:

[0008] S1. Prepare a Z-shaped sheet metal part, which includes a first table, a second table, and a connecting body. The first table and the second table are integrated by the connecting body and are arranged in parallel. An annular groove is provided on the upper surface of the first table, such that the depth of the annular groove is 0.5-2mm lower than the upper surface of the first table, and the width is 0.5-1mm greater than the annular outer diameter of the column part to be welded.

[0009] S2. A first chamfer is provided on the outer edge of the annular groove of the Z-shaped sheet metal part, and a second chamfer is provided on the outer edge of the bottom contact surface where the cylindrical part is located.

[0010] S3. Perform surface treatment on the Z-shaped sheet metal parts and column parts, and then preheat them at a temperature of 120-150℃.

[0011] S4. Apply a material layer to the annular groove of the Z-shaped sheet metal part and the contact surface of the column part, and then use laser welding to embed the column part into the annular groove and weld it in place.

[0012] S5. Sn welding material is filled at the connection between the inner and outer sides of the column part and the Z-shaped sheet metal part, and Sn welding operation is performed.

[0013] Furthermore, the angle between the first chamfer and the horizontal direction is 30-45 degrees;

[0014] The second chamfer is at an angle of 45-60 degrees to the horizontal.

[0015] Furthermore, several sets of outwardly protruding ribs are distributed along the radial direction of the first and second chamfers, so that when the column part is embedded in the annular groove, the ribs on the first chamfer and the ribs on the second chamfer are staggered.

[0016] Furthermore, the height of the ribs protrudes from the surface by 0.1 to 0.2 mm, and they are distributed in an oblique strip shape.

[0017] Furthermore, the surface pretreatment operation in S3 specifically includes:

[0018] S301. Immerse the column part and Z-shaped sheet metal part in alkaline solution and perform ultrasonic vibration treatment, controlling the frequency between 20kHz and 40kHz.

[0019] S302. After being immersed in alkaline solution, the cylindrical parts and Z-shaped sheet metal parts are placed in pickling solution and ultrasonic vibration treatment is carried out simultaneously, with the frequency controlled between 40kHz and 60kHz.

[0020] S303. Place the pickled cylindrical parts and Z-shaped sheet metal parts into a drying oven and control the temperature at 150-180℃.

[0021] Furthermore, in step S301, the alkaline solution used is an 8%–10% NaOH solution, the treatment temperature is 40–60°C, and the treatment time is 10–15 min.

[0022] Furthermore, in S302, the pickling solution used is pickled in two steps, namely acid solution A and acid solution B. Acid solution A includes 300 mL / L hydrochloric acid, 60 mL / L phosphoric acid, 80 mL / L stabilizer, and 2 mL / L surfactant mixed in a molar ratio of 15:3:4:0.1. The cylindrical parts and Z-shaped sheet metal parts are immersed in the solution at a temperature of 30-50°C for 1-2 minutes.

[0023] The acid solution B comprises 300 mL / L hydrofluoric acid, 200 mL / L sulfuric acid, 240 mL / L hydrogen peroxide, 0.5 g / L pickling corrosion inhibitor, and 2 mL / L surfactant mixed in a molar ratio of 15:10:12:0.1:0.2. The cylindrical parts and Z-shaped sheet metal parts are then immersed in the solution at a temperature of 30–50°C for 2–3 minutes.

[0024] Furthermore, the coating material layer is in the form of powder or paste, and is uniformly coated on the contact surface of the annular groove and the cylindrical part, and then cured and dried before welding is performed.

[0025] Furthermore, in step S5, the welding temperature is 180–200°C, and the welding time is 160–180 seconds.

[0026] Furthermore, in step S5, after welding is completed, the sample is placed in a constant temperature chamber at 80-100°C and left to stand for 12-24 hours.

[0027] The beneficial effects of this invention are:

[0028] 1. This application achieves effective fixation and reserved space for Sn welding material by precisely designing the annular groove of the Z-shaped sheet metal part and the dimensions of the cylindrical part, thereby improving the stability and reliability of the welded structure.

[0029] 2. The chamfered and ribbed structure designed in this application helps reduce misalignment and instability during the welding process, and reduces welding defects such as porosity and cracks. Furthermore, the chamfered design helps improve welding stress distribution, reduce welding stress concentration, and increase the fatigue life of the welded joint. Simultaneously, the design and distribution of the ribs reduce instability during circumferential welding, enhancing the overall strength of the welded structure.

[0030] 3. This application employs surface pretreatment (including alkaline washing and acid washing) and high-temperature drying on Z-shaped sheet metal parts and cylindrical components to effectively remove surface grease, dirt, and oxide layers, providing a clean and dry welding surface, thereby improving welding quality. The acid washing treatment prevents re-oxidation of the metal surface and enhances the corrosion resistance of the welded structure.

[0031] 4. The post-weld treatment of this application (such as placing it in a constant temperature chamber for static rest) helps to eliminate welding stress, improve the overall performance of the welded joint, and the application of laser welding and Sn welding technology improves welding accuracy and efficiency, and shortens the production cycle. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0033] Figure 1 This is a schematic diagram of the overall process of an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the overall structure of the workpiece welding and forming according to an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the columnar part structure according to an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of the Z-shaped sheet metal part structure according to an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the combined structure of the cylindrical part and the Z-shaped sheet metal part according to an embodiment of the present invention;

[0038] Figure 6 This is a schematic cross-sectional view of the workpiece welded and formed according to an embodiment of the present invention;

[0039] Figure 7 This is an embodiment of the present invention. Figure 6 A partial structural diagram at point A in the middle. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0041] like Figure 1 ,like Figure 2 As shown, this embodiment of the invention provides a process for welding a cylindrical part to a sheet metal part, including the following steps:

[0042] S1, such as Figure 4 As shown, a Z-shaped sheet metal part 2 is prepared. The Z-shaped sheet metal part 2 includes a first platform 21, a second platform 22, and a connecting body 23. The first platform 21 and the second platform 22 are integrated through the connecting body 23, and the first platform 21 and the second platform 22 are arranged in parallel. An annular groove 201 is provided on the upper surface of the first platform 21, so that the depth of the annular groove 201 is 0.5-2mm lower than the upper surface of the first platform 21, and the width is 0.5-1mm greater than the annular outer diameter of the column part 1 to be welded. This cutting method can effectively fix the Z-shaped sheet metal part 2 and the column part 1, while reserving space for Sn welding material 3 to form a gap filling, thereby improving the contact surface with the Z-shaped sheet metal part 2 and the column part 1 at the same time.

[0043] S2. A first chamfer 202 is formed on the outer edge of the annular groove 201 of the Z-shaped sheet metal part 2, with the first chamfer 202 having an angle of 30-45 degrees with the horizontal direction; at the same time, a second chamfer 101 is formed on the outer edge of the bottom contact surface where the column part 1 is located, with the second chamfer 101 having an angle of 45-60 degrees with the horizontal direction. This chamfer design facilitates the transfer of the column part 1 to the annular groove 201 of the Z-shaped sheet metal part 2 (there will be a gap at the connection), effectively matching and connecting, reducing misalignment, ensuring precise fit during welding, and when the designed first chamfer 202 and second chamfer 101 match each other, it improves the distribution of welding stress and enhances welding quality. These angles help distribute heat and stress during the welding process.

[0044] like Figure 3 As shown, in order to achieve the bonding between the Z-shaped sheet metal part 2 and the column part 1, several sets of outwardly protruding ribs 11 are distributed along the radial direction of the first chamfer 202 and the second chamfer 101. When the column part 1 is embedded in the annular groove 201, the ribs 11 on the first chamfer 202 and the ribs 11 on the second chamfer 101 are staggered. The height of the ribs 11 protrudes from the surface by 0.1 to 0.2 mm and is distributed in an oblique strip shape. This distribution method can reduce the instability when welding in the circumferential direction.

[0045] S3. Perform surface treatment on the Z-shaped sheet metal part 2 and the cylindrical part 1. The surface pretreatment operation specifically includes:

[0046] S301. Immerse the cylindrical part 1 and the Z-shaped sheet metal part 2 in an alkaline solution and perform ultrasonic vibration treatment, controlling the frequency between 20kHz and 40kHz. The alkaline solution used is an 8%–10% NaOH solution, the treatment temperature is 40–60℃, and the treatment time is 10–15 minutes. Alkaline washing can effectively remove grease, dirt, oil stains, and other organic contaminants from the metal surface. These substances may affect welding quality, especially during the formation of the molten pool and the solidification of the weld metal. Furthermore, alkaline washing can remove these oxide layers, exposing a clean metal surface, which is beneficial for the wetting and flow of the solder during welding. It can reduce welding defects such as porosity, slag inclusions, and lack of fusion, thereby improving the quality and performance of the weld joint. Alkaline washing provides a clean surface, enhancing the adhesion of subsequent coatings.

[0047] S302. The column part 1 and Z-shaped sheet metal part 2, which have been immersed in alkaline solution, are placed in pickling solution and ultrasonic vibration treatment is carried out simultaneously, with the frequency controlled between 40kHz and 60kHz.

[0048] The pickling solution used employs a two-step pickling process, namely acid solution A and acid solution B. Acid solution A consists of 300 mL / L hydrochloric acid, 60 mL / L phosphoric acid, 80 mL / L stabilizer, and 2 mL / L surfactant mixed in a molar ratio of 15:3:4:0.1. The cylindrical part 1 and the Z-shaped sheet metal part 2 are immersed in the solution at a temperature of 30–50°C for 1–2 minutes. Acid solution A is used to remove the black scale, inclusions, and some oxide scale from the weld joints and weld seams.

[0049] Acid solution B comprises 300 mL / L hydrofluoric acid, 200 mL / L sulfuric acid, 240 mL / L hydrogen peroxide, 0.5 g / L pickling corrosion inhibitor, and 2 mL / L surfactant, mixed in a molar ratio of 15:10:12:0.1:0.2. The cylindrical part 1 and the Z-shaped sheet metal part 2 are immersed in this solution at 30–50°C for 2–3 minutes to remove the gray film from the surface, achieving a near-mirror-like shine. This process ensures effective pickling while controlling the corrosion rate, guaranteeing the surface quality of the workpiece and the performance of subsequent processing. After pickling, the surfaces of the cylindrical part 1 and the Z-shaped sheet metal part 2, where they are to be welded, achieve a uniform surface condition, providing consistent surface conditions for welding and facilitating process control. Pickling also provides a clean surface, enhancing the adhesion of subsequent coatings.

[0050] S303. Place the pickled column part 1 and Z-shaped sheet metal part 2 into a drying oven and control the temperature at 150-180℃. High-temperature drying can completely remove the pickling liquid and moisture remaining on the metal surface, prevent these liquids from producing porosity, slag inclusions or other welding defects during the welding process, and prevent the metal surface from re-oxidizing in the air, especially in humid environments, where the metal surface is prone to absorbing moisture and reforming an oxide film in the air.

[0051] Preheating is then performed at 120–150°C. This preheating reduces the cooling rate of the weld zone, decreasing thermal stress caused by rapid heating and cooling, thus reducing welding deformation. It also lowers the hardness of the weld and heat-affected zone, preventing the formation of brittle martensitic structures. Furthermore, it helps reduce welding defects such as porosity and cracks because preheating reduces the temperature difference between the weld metal and the base metal, slowing the cooling rate and reducing porosity formation. Preheating also improves the microstructure of the weld joint, enhancing its toughness and plasticity, thereby improving the overall performance of the weld joint. In this application, preheating reduces the need for post-weld heat treatment (such as stress-relieving heat treatment), saving time and costs. It is particularly helpful in preventing cold cracking, especially when welding high-carbon steel or other materials prone to cold cracking.

[0052] S4. Apply material layer 301 to the contact surface of the annular groove 201 of the Z-shaped sheet metal part 2 and the cylindrical part 1, and then use laser welding to embed the cylindrical part 1 into the annular groove 201 and weld it in place. Figure 5 As shown, at this time, only the column part 1 is welded as a whole onto the annular groove 201 of the Z-shaped sheet metal part 2, and there are still gaps at its edges.

[0053] like Figure 6 , Figure 7 As shown, the coating material layer 301 is a powder or paste, which is uniformly applied to the contact surfaces of the annular groove 201 and the cylindrical part 1, and then cured and dried before welding. This laser welding method increases welding strength or provides protection, and improves welding accuracy and efficiency.

[0054] S5. Sn welding material 3 is filled at the inner and outer connection points of the column part 1 and the Z-shaped sheet metal part 2, and Sn welding is performed. This Sn welding material 3, which fills both the inner and outer sides (used to fill the gap between the annular groove 201 and the column part 1), improves welding accuracy and efficiency. The welding temperature is 180-200℃, the welding time is 160-180s, and the drying oven temperature is controlled at 150-180℃. The welding temperature is 180-200℃ to ensure that the material is not damaged due to overheating. After welding, it is placed in a constant temperature oven at 80-100℃ for 12-24 hours to ensure that the welding is thorough and uniform.

[0055]

[0056]

[0057] As shown in Table 1 above, the chamfering and Sn welding processes of this application greatly improve the compressive and tensile strength of the welded parts.

[0058] In this application, thermal stress and structural strength during the welding process are taken into account, and the performance and service life of the welded joint are improved through design and process optimization.

[0059] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A process for welding a cylindrical part to a sheet metal part, characterized in that, Includes the following steps: S1. Prepare Z-shaped sheet metal parts (2). The Z-shaped sheet metal parts (2) include a first table (21), a second table (22), and a connecting body (23). The first table (21) and the second table (22) are integrated through the connecting body (23) and the first table (21) and the second table (22) are arranged in parallel. An annular groove (201) is provided on the upper surface of the first table (21). The depth of the annular groove (201) is 0.5-2mm lower than the upper surface of the first table (21), and the width is 0.5-1mm greater than the annular outer diameter of the column part (1) to be welded. S2. A first chamfer (202) is provided on the outer edge of the annular groove (201) of the Z-shaped sheet metal part (2), and a second chamfer (101) is provided on the outer edge of the bottom contact surface where the column part (1) is located. S3. Perform surface treatment on the Z-shaped sheet metal part (2) and the column part (1), and then preheat at a temperature of 120~150℃. S4. Apply a material layer (301) to the annular groove (201) of the Z-shaped sheet metal part (2) and the contact surface of the column part (1), and then use laser welding to embed the column part (1) into the annular groove (201) and weld it in place. S5. Sn welding material (3) is filled at the connection between the inner and outer sides of the column part (1) and the Z-shaped sheet metal part (2), and Sn welding operation is performed. The surface pretreatment operation in S3 specifically includes: S301. Immerse the column part (1) and Z-shaped sheet metal part (2) in an alkaline solution and perform ultrasonic vibration treatment, controlling the frequency between 20 kHz and 40 kHz; the alkaline solution used is 8% to 10% NaOH solution, the treatment temperature is 40 to 60℃, and the treatment time is 10 to 15 min. S302. The cylindrical part (1) and the Z-shaped sheet metal part (2) after being immersed in alkaline solution are placed in pickling solution and subjected to ultrasonic vibration treatment simultaneously, with the frequency controlled between 40 kHz and 60 kHz. The pickling solution used is pickled in two steps, namely acid solution A and acid solution B. Acid solution A includes 300 mL / L hydrochloric acid, 60 mL / L phosphoric acid, 80 mL / L stabilizer, and 2 mL / L surfactant mixed in a molar ratio of 15:3:4:0.

1. The cylindrical part (1) and the Z-shaped sheet metal part (2) are immersed in the solution at a temperature of 30~50℃ for 1-2 minutes. S303. Place the pickled column part (1) and Z-shaped sheet metal part (2) into a drying oven and control the temperature to 150-180℃.

2. The process for welding of column parts with sheet metal parts according to claim 1, characterized in that, The angle between the first chamfer (202) and the horizontal direction is 30-45 degrees; The second chamfer (101) has an angle of 45-60 degrees with the horizontal direction.

3. The process for welding of column parts with sheet metal parts according to claim 2, characterized in that, A number of outwardly protruding ribs (11) are distributed along the radial direction of the first chamfer (202) and the second chamfer (101), so that when the column part (1) is embedded in the annular groove (201), the ribs (11) on the first chamfer (202) and the ribs (11) on the second chamfer (101) are staggered.

4. The process for welding of column parts with sheet metal parts according to claim 3, characterized in that, The height of the rib (11) protrudes from the surface by 0.1~0.2mm and is distributed in an oblique strip shape; The acid solution B comprises 300 mL / L hydrofluoric acid, 200 mL / L sulfuric acid, 240 mL / L hydrogen peroxide, 0.5 g / L pickling corrosion inhibitor, and 2 mL / L surfactant mixed in a molar ratio of 15:10:12:0.1:0.2, and the column part (1) and the Z-shaped sheet metal part (2) are immersed in the solution at a temperature of 30~50℃ for 2-3 minutes.

5. The process for welding of column parts with sheet metal parts according to claim 1, characterized in that, The coating material layer (301) is a powder or paste, and it is uniformly coated on the contact surface of the annular groove (201) and the column part (1), and then cured and dried before welding.

6. The process for welding of column parts with sheet metal parts according to claim 1, characterized in that, In step S5, the welding temperature is 180~200℃ and the welding time is 160~180s.

7. The process for welding of column parts with sheet metal parts according to claim 1, characterized in that, In step S5, after welding is completed, the sample is placed in a constant temperature chamber at 80~100℃ and left to stand for 12~24 hours.

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