A metal water pipe stamping and welding forming process

Abstract

This invention discloses a metal water pipe stamping and welding forming process, relating to the field of water pipe processing technology. This process replaces the traditional flat plate with a water outlet closure consisting of an arc-shaped sealing section and a straight section. The continuous, smooth arc surface makes the product lines smooth and rounded, giving it a more textured and modern look, better adapting to different home environments and enhancing the product's quality. It eliminates sharp edges, avoiding the risk of bumps and knocks during daily use and improving the product's safety performance. The arc-shaped sealing section guides the water flow smoothly, reducing turbulence and splashing at the outlet, lowering water noise, and making the water flow more concentrated and gentle, thus improving the user experience. The arc-shaped transition structure of the sealing section disperses stress concentration, providing stronger impact and deformation resistance compared to a flat, angular structure, extending the product's service life.

Description

Technical Field

[0001] This invention relates to the field of water pipe processing technology, and in particular to a metal water pipe stamping and welding forming process. Background Technology

[0002] A faucet is essentially a valve that controls the flow of water. It can be used in places such as washbasins, bathtubs, showers, and kitchen sinks, bringing great convenience to people's lives.

[0003] Faucets generally include round tube faucets and square tube faucets. Square tube faucets are currently made by welding a flat plate to one end of a hollow square tube, and then opening a water outlet on the side of the hollow square tube near the flat plate to connect the water outlet connector.

[0004] The following defects exist when using this type of square tube faucet: (1) The sharp angles make the structure visually rigid and lack a smooth feel, which is difficult to meet the requirements of modern home furnishing for product aesthetics; (2) The sharp angles are prone to bumps and knocks during daily operation, which poses certain safety hazards; (3) The planar structure is prone to causing water flow turbulence at the outlet, resulting in water splashing, increased noise, and affecting the user experience; (4) Due to the abrupt change in cross-section at the root of the polygonal structure, there will be obvious stress concentration when subjected to force. The water pipe needs to withstand water pressure fluctuations and external collisions during use. Cracks are prone to occur in this part, which reduces the overall structural strength and durability, and the impact resistance and deformation resistance are weak. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing technology, the present invention provides a metal water pipe stamping and welding process to solve the problems of poor aesthetics, certain safety hazards, poor user experience, and weak impact and deformation resistance of existing square tube faucets.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a metal water pipe stamping and welding forming process, comprising the following steps: S1: Water outlet pipe pretreatment: Take a hollow square tube, press and bend it to form a water outlet pipe with a preset arc, and then cut and process one end of the water outlet pipe to form the first plane. S2: Forming of the water outlet seal: including the following steps: 1. Initial forming of the water outlet sealing component: Take a single piece of sheet metal and use the first stamping die to perform initial stamping processing on the sheet metal to form an initial stamping sealing blank with an arc-shaped outer surface. The initial stamping sealing blank has an outer edge. 2. Precision forming of the water outlet sealing part: The initial pressure sealing blank is stamped using a second stamping die to form a precision pressure sealing blank containing an arc-shaped sealing part, a straight part and an outer edge part with smooth transition connection. The two ends of the straight part are respectively connected to the arc-shaped sealing part and the outer edge part, and one end of the straight part is set as a second plane that is adapted to the first plane. 3. Shaping of the water outlet sealing component: The R-angle of the precision-pressed sealing blank is shaped using a third stamping die; 4. Cut off the outer edge: Cut the outer edge of the precision-pressed sealing blank, then passivate the R-angle and perform low-temperature treatment to form the required water outlet sealing part; S3: Assembly and welding: Align and fit the first plane at one end of the water outlet pipe with the second plane at one end of the straight section of the water outlet head sealing part, fix it by welding process, and then polish it to form a semi-closed water pipe body. S4: Outlet processing: Cut one side of the semi-enclosed water pipe body after welding to form the outlet.

[0007] Preferably, the water outlet is located on both the water outlet head seal and the water outlet pipe.

[0008] Preferably, the height of the straight section is 6mm-10mm.

[0009] Preferably, the wall thickness of the straight section is not less than the wall thickness of the outlet pipe.

[0010] Preferably, the inner wall of the water outlet is smoothly connected to the inner surface of the water outlet head seal and the water outlet pipe, without any sharp edges.

[0011] Preferably, in step one, a first stamping die with a polyurethane elastic blank holder is used, with a blank holder force of 5MPa-8MPa, a stretching speed of 50mm / s-80mm / s, a die gap of 1.05-1.1 times the thickness of the sheet metal wall, and a single stretching coefficient of 0.75-0.8.

[0012] Preferably, in step two, a three-stage speed stamping is used: 10mm / s-20mm / s for the contact stage, 30mm / s-50mm / s for the stretching stage, and 0mm / s for the holding stage, with a holding time of 1s-2s.

[0013] Preferably, in step three, a third stamping die made of YG8 cemented carbide is used, the die surface is coated with a 3μm-5μm DLC coating, the friction coefficient is not greater than 0.1, and an integrated cold pressing and micro-leveling process is adopted, with a forming pressure of 10MP-15MP.

[0014] Preferably, in step four, the low-temperature aging treatment is carried out at a temperature of 120℃-150℃ for 2-3 hours, and the R-angle passivation treatment is carried out by soaking in a mixture of 8%-12% nitric acid and hydrofluoric acid for 5-10 minutes.

[0015] Preferably, the first stamping die includes a first upper die and a first lower die. A positioning element is fixed on the side of the first upper die facing the first lower die. A first punch that moves along a direction perpendicular to the bottom surface of the first upper die is provided on the side of the positioning element facing the first lower die. A positioning groove adapted to the positioning element is opened on the side of the first lower die facing the first upper die. A first forming groove adapted to the first punch is opened on the bottom surface of the positioning groove.

[0016] Compared with the prior art, the beneficial effects that this invention can achieve are: (1) By setting the water outlet sealing part, which includes an arc-shaped sealing part and a straight part, instead of the traditional flat plate, the continuous smooth arc surface makes the product lines smooth and rounded, and the visual texture and modernity are more suitable for different styles of home environment, which can improve the product grade, eliminate sharp edges and corners, avoid the risk of bumps and collisions in daily use, and improve the safety protection performance of the product. The arc-shaped sealing part can guide the water flow to transition smoothly, reduce the turbulence and splashing of the water flow at the outlet, reduce water flow noise, make the water flow more concentrated and gentle, and improve the user experience. The arc transition structure of the arc-shaped sealing part disperses the stress concentration. Compared with the flat edge structure, it has stronger impact resistance and deformation resistance, and extends the service life of the product. (2) Through the cooperation of the arc-shaped closed part and the straight part, the second plane of the straight part and the first plane end face of the water outlet pipe are more closely fitted, which greatly reduces assembly error and improves the overall consistency of the product. The plane welding belongs to the category of fillet welding / butt welding. The positioning and fixing of the water outlet head closure and the water outlet pipe are more stable and convenient. The molten pool is stable under the action of gravity, and it is easy to control the weld formation, which can effectively avoid defects such as incomplete penetration and weld beads. At the same time, the plane weld is convenient for automated welding equipment (such as argon arc welding machine) to operate, which greatly improves production efficiency and reduces the dependence on the welding skills. The straight part serves as a transition section. It achieves a smooth / rigid transition between the arc-shaped sealing part and the water outlet pipe, avoiding stress concentration caused by direct contact of curved surfaces. Under stress, the stress can be evenly diffused through the straight section. The stress distribution of the flat weld is uniform and the rigidity is strong, which significantly improves the impact resistance and deformation resistance of the water outlet sealing part, extends the service life of the product, and avoids the local collapse or diameter expansion that is easily caused by direct contact between the arc-shaped sealing part and the water outlet pipe when exposed to heat. If the welding position is slightly off, the flat weld can still be corrected by adjusting the angle. However, once the arc-shaped sealing part and the water outlet pipe are directly welded, misalignment will result in an irreversible fracture and a very poor visual effect. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the water outlet sealing component of the present invention; Figure 2 This is a schematic diagram of the water outlet pipe after bending and cutting, and the first planar structure of the present invention; Figure 3This is a schematic diagram of the structure of the water outlet pipe and the water outlet head sealing component after welding according to the present invention; Figure 4 This is a schematic diagram of the water outlet pipe, water outlet head sealing component, and water outlet structure of the present invention; Figure 5 This is a schematic diagram of the structure of the water outlet pipe, water outlet head sealing component, water outlet and water outlet connector of the present invention; Figure 6 This is a schematic diagram of the water outlet pipe, water outlet head sealing component, connecting round pipe, and water outlet connector of the present invention. Figure 7 This is a schematic diagram of the initial pressure closed blank structure formed by the sheet metal of the present invention after one stamping. Figure 8 This is a schematic diagram of the structure of the precision-pressed closed blank formed after secondary stamping according to the present invention; Figure 9 This is a schematic diagram of the structure of the precision-pressed sealed blank after shaping according to the present invention; Figure 10 This is a schematic diagram of the water outlet sealing component structure formed after cutting the precision-pressed sealing blank of the present invention; Figure 11 This is a schematic diagram of the cross-sectional structure of the first stamping die of the present invention; Figure 12 This is a schematic diagram of the cross-sectional structure of the second stamping die of the present invention; The components are as follows: 1. Water outlet pipe; 11. First plane; 12. Connecting surface; 2. Water outlet head sealing component; 21. Straight section; 211. Second plane; 22. Arc-shaped sealing section; 3. Water outlet connector; 4. Connecting round pipe; 5. Water outlet; 6. Outer edge; 61. Arc-shaped connecting section; 7. First upper template; 8. First lower template; 81. Positioning groove; 82. First forming groove; 9. Positioning component; 10. First punch; 13. Second upper template; 14. Second lower template; 141. Second forming groove; 15. Second punch; 16. Lower pressure plate. Detailed Implementation

[0018] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention is further described below in conjunction with specific embodiments. However, the following embodiments are merely preferred embodiments of this invention and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments in the implementation methods without creative effort are all within the protection scope of this invention.

[0019] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the present invention provides a metal water pipe stamping and welding forming process, including the following steps: S1: Pre-treatment of water outlet pipe 1: Take a hollow square tube and press and bend it into shape (a CNC bending machine can be used to form the hollow square tube into a water outlet pipe 1 with a preset arc. Then cut one end of the water outlet pipe 1 (laser cutting can be used) to form the first plane 11 at one end. S2: Forming of water outlet sealing component 2: Take a plate of the same material as the hollow square tube and stamp it to form water outlet sealing component 2 (the material of the hollow square tube and the plate can be 304 stainless steel, 316L stainless steel, galvanized steel plate or aluminum alloy plate, etc.). Water outlet sealing component 2 has an arc-shaped sealing part 22 and a straight part 21 that are smoothly connected. One end of the straight part 21 is set as a second plane 211 that is adapted to the first plane 11. S1 and S2 can be performed simultaneously, with no specific order of processing and forming.

[0020] S3: Assembly and welding: Align and fit the first plane 11 at one end of the water outlet pipe 1 with the second plane 211 at one end of the straight part 21 of the water outlet head closure 2, fix it by welding, and then polish it to form a semi-closed water pipe body. S4: Outlet 5 processing: Cut one side of the semi-enclosed water pipe body after welding to form outlet 5; By replacing the traditional flat plate with a water outlet closure 2 consisting of an arc-shaped closure 22 and a straight section 21, the continuous smooth arc surface makes the product lines smooth and rounded, giving it a more textured and modern look. This allows it to better adapt to different home environments, enhancing the product's quality. It also eliminates sharp edges, avoiding the risk of bumps and knocks during daily use and improving the product's safety performance. The arc-shaped closure 22 guides the water flow smoothly, reducing turbulence and splashing at the water outlet 5, lowering water noise, and making the water flow more concentrated and gentle, thus improving the user experience. The arc transition structure of the arc-shaped closure 22 disperses stress concentration, making it more impact-resistant and deformation-resistant than a flat, angular structure, thus extending the product's service life. The cooperation between the arc-shaped closure 22 and the straight section 21 ensures a higher fit between the second plane 211 of the straight section 21 and the end face of the first plane 11 of the water outlet pipe 1, significantly reducing assembly errors and improving overall product consistency. Planar welding falls under the category of fillet welding / butt welding, making the positioning and fixing of the water outlet closure 2 and the water outlet pipe 1 more stable and convenient. The molten pool is stable under gravity, making it easy to control weld formation and effectively avoiding defects such as incomplete penetration and weld beads. Simultaneously, planar welds facilitate automated welding equipment (such as argon arc welding machines), significantly improving production efficiency and reducing reliance on welder skills. The straight section 21 serves as a transition segment. It achieves a smooth / rigid transition between the arc-shaped sealing part 22 and the water outlet pipe 1, avoiding stress concentration caused by direct contact of curved surfaces. When under stress, the stress can be evenly diffused through the straight section. The stress distribution of the flat weld is uniform and the rigidity is strong, which significantly improves the impact resistance and deformation resistance of the water outlet sealing part 2, extends the service life of the product, and avoids the local collapse or diameter expansion that is easily caused by direct contact between the arc-shaped sealing part 22 and the water outlet pipe 1 when exposed to heat. If the welding position is slightly off, the flat weld can still be corrected by adjusting the angle. However, once the arc-shaped sealing part 22 and the water outlet pipe 1 are directly welded, it will be an irreversible fracture and the visual effect will be extremely poor. When using a single arc-shaped sealing part 22 to weld with the water outlet pipe 1, the arc-shaped sealing part 22 cannot be well positioned and fixed, and is prone to misalignment, deviation, and poor fit, making welding extremely difficult. Similarly, when the water outlet pipe 1 is punched and bent without cutting, one end is an arc-shaped surface. Arc-shaped surface welding is a spatial curve weld, the molten pool is unstable, and it is easy to weld through, weld beads, and incomplete penetration, resulting in a very high risk of leakage. Arc-shaped surface welding cannot guarantee flatness, has poor strength, and suffers from concentrated stress, large welding thermal deformation, and overall structural instability.

[0021] like Figure 4 and Figure 5 As shown, the water outlet 5 is located on both the water outlet head seal 2 and the water outlet pipe 1. The water outlet 5 is welded and fixed with the water outlet connector 3, which is used to connect the water outlet component (it can be fixed by screws). With this configuration, the edge of the outlet 5 can be reinforced by the outlet head sealing component 2, which offsets the strength loss of the outlet pipe 1. The overall structure is more rigid and avoids the situation where the outlet 5 is only opened on the side wall of the outlet pipe 1, which is prone to stress concentration and cracking at the outlet 5 of the outlet pipe 1. When welding the outlet connector 3 later, the outlet connector 3 is fixed to both the outlet head sealing component 2 and the outlet pipe 1. After welding, the three form a triple rigid connection with higher strength. This avoids the risk of the outlet connector 3 warping or pulling off due to single-sided welding when fixing the outlet connector 3 only to the outlet 5 opened on the outlet pipe 1. The pressure bearing capacity is significantly improved and the overall structural stability is stronger. In addition, the outlet 5 spans the two interfaces of the outlet pipe 1 and the outlet head seal 2. The water flow needs to break through the seal of both contact surfaces simultaneously to leak. Compared with the single-interface seal of only opening the outlet 5 on one side of the outlet pipe 1, the leakage path is more complex and the probability of leakage decreases exponentially. The outlet connector 3 is welded to the two interfaces of the outlet pipe 1 and the outlet head seal 2. The weld covers the two welded joints of the outlet pipe 1 and the outlet head seal 2, directly sealing part of the original weld gap between the outlet head seal 2 and the outlet pipe 1, and cutting the two welded joints of the outlet pipe 1 and the outlet head seal 2, reducing the probability of leakage between the outlet pipe 1 and the outlet head seal 2.

[0022] like Figure 7 , Figure 8 , Figure 9 and Figure 10 As shown, S2 specifically includes the following steps: 1. Initial Forming of Water Outlet Sealing Part 2: Take a single sheet of material and perform low-temperature stress-relief annealing at 180℃-220℃ for 1-2 hours, followed by furnace cooling to eliminate residual stress from rolling and prevent stress concentration during stretching that could lead to cracking of the R-corner. This also reduces springback during subsequent stretching. After annealing, clean the surface of the material and apply a composite lubricant of solid lubricant and lubricating oil (the solid lubricant is molybdenum disulfide, particle size ≤5μm, coating thickness 0.01mm-0.02mm) to reduce the coefficient of friction between the material and the die (≤0.1), minimize roughening in the R-corner area, and improve material flowability. Use the first stamping die to perform initial stamping processing on the material, forming an initial-pressed sealing blank with an arc-shaped outer surface. The initial-pressed sealing blank has an outer edge 6 (e.g., Figure 7 As shown, a first stamping die with a polyurethane elastic blank holder is used, with a blank holder force of 5MPa-8MPa, a stretching speed of 50mm / s-80mm / s, a die gap of 1.05-1.1 times the plate wall thickness, and a single stretching coefficient of 0.75-0.8. 2. Precision forming of the water outlet sealing component 2: The initial pressing sealing blank is stamped using a second stamping die to form a precision pressing sealing blank comprising an arc-shaped sealing part 22, a straight part 21, and an outer edge part 6. The two ends of the straight part 21 are connected to the arc-shaped sealing part 22 and the outer edge part 6 respectively (e.g., ...). Figure 8 As shown, a three-stage speed stamping process is adopted: 10mm / s-20mm / s during the contact stage, 30mm / s-50mm / s during the stretching stage, and 0mm / s during the holding stage, with a holding time of 1s-2s, to avoid R-corner cracking caused by impact. 3. Shaping of the water outlet sealing component 2: The R-angle of the precision-pressed sealing blank is shaped using a third stamping die (e.g., ...). Figure 9As shown), to make the product more stable, the third stamping die is made of YG8 cemented carbide. The die surface is coated with a 3μm-5μm DLC coating with a friction coefficient of no more than 0.1. It is compatible with stainless steel cold work hardening layer to avoid R-corner burrs and scratches during shaping. The integrated process of cold pressing and micro-leveling is adopted. The shaping pressure is 10MP-15MP and the holding time is 2s-3s to eliminate tensile residual stress and further calibrate the R-corner radius. After shaping, the R-corner surface roughness Ra≤0.4μm, without micro-cracks, wall thickness uniformity≥92%, and radius tolerance≤±0.05mm. 4. Cutting off the outer edge 6: The outer edge 6 of the precision-pressed sealing blank is cut (CNC laser cutting can be used for cutting), and then the R-angle is blunted and subjected to low-temperature treatment to form the required water outlet sealing part 2 (e.g., Figure 10 As shown), the low-temperature aging treatment temperature is 120℃-150℃, and the holding time is 2h-3h. The R-corner passivation treatment uses a mixture of 8%-12% nitric acid and hydrofluoric acid, and soaks for 5min-10min to remove cutting burrs, surface oxide layer and tensile residual stress, improve the corrosion resistance of the R-corner area, and avoid stress corrosion cracking in subsequent use. The low-temperature treatment further stabilizes the R-corner dimensions and avoids R-corner springback deformation in subsequent processing and use. The first and second stamping dies here are respectively equipped with a first fixing structure and a second fixing structure for pressing and fixing the sheet metal. Since the water outlet closure 2 has an added straight section 21, the stamping depth is deeper. The outer edge 6 of the sheet metal is pressed and fixed by the corresponding fixing structure before the stamping work is carried out. This prevents the sheet metal edge from wrinkling, wavy or warping when the stamping depth is large in the straight section 21 and the arc-shaped closure 22. If the outer edge 6 is not pressed, the material cannot flow evenly, resulting in excessive local stress. This ensures the flatness of the finished product surface and avoids product scrap. After the outer edge 6 is pressed, the stamping process is a gradual flow process. It forcibly controls the flow speed of the material from the outer edge to the center, disperses the stress, and avoids the tearing and thinning caused by excessive stretching at the transition fillet between the arc-shaped closed part 22 and the straight part 21.

[0023] like Figure 11 As shown, the first fixing structure includes a positioning element 9 and a positioning groove 81. The first stamping die includes a first upper die plate 7 and a first lower die plate 8. The positioning element 9 is fixed on the side of the first upper die plate 7 facing the first lower die plate 8. The positioning element 9 is provided on the side of the first lower die plate 8 facing the first lower die plate 8. The first punch 10 moves along the direction perpendicular to the bottom surface of the first upper die plate 7. The first lower die plate 8 is provided on the side of the first upper die plate 8 facing the first upper die plate 8. The positioning groove 81 is adapted to the positioning element 9. The bottom surface of the positioning groove 81 is provided with a first forming groove 82 adapted to the first punch 10. In use, a single sheet of material is placed in the positioning groove 81, and the first upper mold plate 7 and the first lower mold plate 8 are closed. At this time, the positioning part 9 presses and fixes the single sheet of material. Then, the first punch 10 is driven by a cylinder or other driving part to move, so that it moves out of the positioning part 9 and cooperates with the first forming groove 82 to form the material. Figure 7 The outer surface shown is an arc-shaped initial pressure closed blank.

[0024] like Figure 12 As shown, the second fixed structure includes a lower pressure plate 16, and the second stamping die includes a second upper template 13 and a second lower template 14. The lower pressure plate 16 is fixed on the surface of the second upper template 13 facing the second lower template 14. A second forming groove 141 is opened on the surface of the second lower template 14 facing the second upper template 13. A second punch 15 is movably disposed in the second upper template 13, moving along the direction perpendicular to the bottom surface of the second upper template 13 and able to penetrate the lower pressure plate 16. In use, the initial pressure closed blank is placed on the second lower template 14, with the outer edge 6 located on the second lower template 14. At this time, the arc-shaped part of the initial pressure closed blank is located in the second forming groove 141. When the second stamping die is closed, the lower pressure plate 16 first presses the outer edge 6 of the initial pressure closed blank, and then drives the second punch 15 to move through the cylinder or other driving components, so that it moves out of the lower pressure plate 16 to cooperate with the second forming groove 141, forming a precision pressure closed blank containing the arc-shaped closed part 22, the straight part 21 and the outer edge 6.

[0025] like Figure 7 , Figure 8 and Figure 9 As shown, the connection between the outer edge 6 and the straight part 21 of the stamped precision-pressed closed blank is an arc-shaped connection part 61, which avoids the outer edge 6 and the straight part 21 from splitting apart due to the stamping of the stamping die in a right-angle state.

[0026] like Figure 1 and Figure 6 As shown, the height of the straight section 21 is 6mm-10mm. The height of 6mm-10mm allows the water outlet seal 2 to have sufficient thickness and rigidity at the welding point to support the weight of the water outlet connector 3 and the internal water pressure. The height of 6mm-10mm provides sufficient material flow margin for the sheet metal during stamping. If it is too high, the risk of sheet metal cracking will increase dramatically; if it is too low, a sufficiently deep cavity structure cannot be formed, resulting in the straight section 21 not being formed properly and "collapsed corner" occurring. The height of the straight section 21 is preferably set to 8mm. By setting the height of the straight section 21 in this way, the welding area and structural rigidity with the water outlet pipe 1 are ensured, while avoiding sheet metal cracking, wrinkling and excessive material waste during the stamping process. This achieves the best balance between forming quality and structural strength. If the height is greater than 10mm, too much waste material will be cut off from the outer edge 6 at the end, increasing the cost. If the height is too low (less than 6mm), the weld is too narrow, the shear strength is low, and it is easy to detach under slight force. If the straight section 21 is too small, the overall rigidity of the head of the water outlet seal 2 is insufficient. After the water outlet connector 3 is installed, due to insufficient support, the head is prone to collapse and deformation under long-term force or water pressure impact.

[0027] The wall thickness of the straight section 21 is not less than the wall thickness of the water outlet pipe 1 (not shown in the figure) to enhance the connection rigidity of the closed end of the water outlet pipe 1 and avoid local collapse at the weld.

[0028] The inner wall of the outlet 5 is smoothly connected to the inner surface of the outlet head seal 2 and the outlet pipe 1, without any sharp edges (not shown in the figure), which effectively reduces water flow resistance, reduces turbulence and water noise, and improves the smoothness of water flow. At the same time, the second plane 211 is precisely fitted with the first plane 11 of the outlet pipe 1, and the gap between the plane welding fits is ≤0.1mm. With high-precision flatness control, the risk of leakage is greatly reduced and the reliability of the welding seal is improved.

[0029] like Figure 4 , Figure 5 and Figure 6 As shown, the other end of the water outlet pipe 1 is welded and fixedly connected to the round pipe 4 (for connecting the water inlet pipe), and the other end of the water outlet pipe 1 is cut to form a connecting surface 12 that fits the outer wall of the round pipe 4.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A metal water pipe stamping and welding forming process, characterized in that, Includes the following steps: S1: Pre-treatment of water outlet pipe (1): Take a hollow square tube, press and bend it to form a water outlet pipe (1) with a preset arc, and then cut and process one end of the water outlet pipe (1) to form the first plane (11). S2: Water outlet closure (2) molding: including the following steps:

1. Water outlet sealing part (2) Initial forming: Take a single piece of plate and use the first stamping die to perform initial stamping processing on the plate to form an initial pressing sealing blank with an arc-shaped outer surface. The initial pressing sealing blank has an outer edge (6).

2. Precision forming of the water outlet sealing part (2): The initial pressure sealing blank is stamped using a second stamping die to form a precision pressure sealing blank containing an arc-shaped sealing part (22), a straight part (21), and an outer edge part (6) with smooth transition connection. The two ends of the straight part (21) are connected to the arc-shaped sealing part (22) and the outer edge part (6) respectively. One end of the straight part (21) is set as a second plane (211) that is adapted to the first plane (11). Three: Water outlet sealing part (2) Shaping: The R angle of the precision-pressed sealing blank is shaped by the third stamping die; 4. Cut off the outer edge (6): Cut the outer edge (6) of the precision-pressed sealing blank, then passivate the R angle and perform low-temperature treatment to form the required water outlet sealing part (2). S3: Assembly and welding: Align and fit the first plane (11) at one end of the water outlet pipe (1) with the second plane (211) at one end of the straight part (21) of the water outlet head sealing part (2), fix it by welding, and then polish it to form a semi-closed water pipe body. S4: Outlet (5) processing: Cut one side of the semi-closed water pipe body after welding to form the outlet (5).

2. The metal water pipe stamping and welding forming process according to claim 1, characterized in that: The outlet (5) is located on both the outlet head seal (2) and the outlet pipe (1).

3. The metal water pipe stamping and welding forming process according to claim 1, characterized in that: The height of the straight section (21) is 6mm-10mm.

4. The metal water pipe stamping and welding forming process according to claim 1, characterized in that: The wall thickness of the straight section (21) is not less than the wall thickness of the outlet pipe (1).

5. The metal water pipe stamping and welding forming process according to claim 1, characterized in that: The inner wall of the outlet (5) is smoothly connected to the inner surface of the outlet head seal (2) and the outlet pipe (1), without any sharp edges.

6. The metal water pipe stamping and welding forming process according to claim 1, characterized in that: In step one of S2, a first stamping die with a polyurethane elastic blank holder is used, with a blank holder force of 5MPa-8MPa, a stretching speed of 50mm / s-80mm / s, a die gap of 1.05-1.1 times the thickness of the sheet metal wall, and a single stretching coefficient of 0.75-0.

8.

7. The metal water pipe stamping and welding forming process according to claim 1, characterized in that: In step two of S2, a three-stage speed stamping is adopted: 10mm / s-20mm / s in the contact stage, 30mm / s-50mm / s in the stretching stage, and 0mm / s in the holding stage, with a holding time of 1s-2s.

8. The metal water pipe stamping and welding forming process according to claim 1, characterized in that: In step three of S2, a third stamping die made of YG8 cemented carbide is used. The die surface is coated with a 3μm-5μm DLC coating with a friction coefficient of no more than 0.

1. The cold pressing and micro-leveling integrated process is adopted, with a forming pressure of 10MP-15MP.

9. The metal water pipe stamping and welding forming process according to claim 1, characterized in that: In step four of S2, the low-temperature aging treatment is carried out at a temperature of 120℃-150℃ for 2-3 hours, and the R-angle passivation treatment is carried out by soaking in a mixture of 8%-12% nitric acid and hydrofluoric acid for 5-10 minutes.

10. The metal water pipe stamping and welding forming process according to claim 1, characterized in that: The first stamping die includes a first upper die (7) and a first lower die (8). A positioning element (9) is fixed on the side of the first upper die (7) facing the first lower die (8). The positioning element (9) is provided with a first punch (10) that moves along the direction perpendicular to the bottom surface of the first upper die (7) on the side facing the first lower die (8). A positioning groove (81) adapted to the positioning element (9) is opened on the side of the first lower die (8) facing the first upper die (8). A first forming groove (82) adapted to the first punch (10) is opened on the bottom surface of the positioning groove (81).

Images