Large nozzle pump shell die forming mold, forming method and design method

Abstract

The application discloses a large-scale pump shell with a nozzle forming die, a forming method and a design method, and the forming die comprises a lower pad, an outer die, an inner die, a lower plug and a side plug. The outer die is detachably arranged at the upper end of the lower pad, the inner die is arranged into the upper part of the outer die from top to bottom, the outer wall of the inner die is attached to the inner wall of the outer die, the inner die is evenly split in the circumferential direction, the inner die is provided with a forming cavity for near-net forming of the outer contour of a blank, the lower end of the lower plug is arranged on the lower pad, the upper end of the lower plug extends into the forming cavity after vertically penetrating through the outer die, the outer end of the side plug is clamped into the outer side of the inner die from outside to inside and the outer end surface is attached to the inner wall of the outer die, and the inner end of the side plug extends into the forming cavity. Compared with the traditional free forging, the metal compactness and the organizational performance of the large-scale pump shell product body are improved under three-way stress, that is, the performance requirements can be met, and the forging part realizes near-net forming, so that the material consumption can be reduced.

Description

Technical Field

[0001] This invention belongs to the field of die forging technology, and particularly relates to large-scale die forging molds, forming methods and design methods for pump housings with nozzles. Background Technology

[0002] Currently, pump housings (cylinders) with nozzles are widely used in power generation and chemical equipment. These pump housings (cylinders) with nozzles have several nozzles evenly arranged on their sides in the circumferential direction.

[0003] Due to limitations in manufacturing equipment capabilities and technology, these types of pump housings (cylinder blocks) with nozzles are typically manufactured using casting. However, the performance of casting is insufficient for high-temperature and high-pressure applications. Therefore, these pump housings (cylinder blocks) with nozzles are now produced by free forging to meet performance requirements. However, forging the cavities and through holes of the pump housings (cylinder blocks) with nozzles requires a significant amount of machining time and also results in substantial material waste. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a large-scale forging die, forming method, and design method for pump housings with nozzles, which can meet performance requirements and reduce material consumption.

[0005] The objective of this invention is achieved through the following technical solution: In a first aspect, a large forging die for a pump housing with a nozzle is provided, comprising: Lower pad; The outer mold is detachably mounted on the upper end of the lower pad. The inner mold is inserted into the upper part of the outer mold from top to bottom. The outer wall of the inner mold fits the inner wall of the outer mold. The inner mold is evenly divided into segments along the circumference. A forming cavity is provided in the inner mold for near-net-shape forming of the outer contour of the blank. The lower end of the lower plug is set on the lower pad plate, and the upper end of the lower plug extends vertically through the outer mold and into the forming cavity. The side plug has its outer end inserted into the outer side of the inner mold from the outside in, with its outer end face fitting against the inner wall of the outer mold. The inner end of the side plug extends inward into the forming cavity.

[0006] Furthermore, the outer diameter of the upper end of the inner mold is larger than the outer diameter of the lower end.

[0007] Furthermore, an upper punch is coaxially provided inside the inner mold. The upper end of the upper punch extends to the upper end face of the inner mold, and the lower end of the upper punch connects to the upper end of the forming cavity. The inner diameter of the upper punch matches the outer diameter of the pressure plate of the upper punch.

[0008] Furthermore, the inner mold is provided with an installation port located outside the forming cavity, and the outer end of the side plug is engaged between the installation port and the inner wall of the outer mold.

[0009] Furthermore, the outer end of the side plug is provided with a conformal arc surface for fitting the inner wall of the outer mold.

[0010] Furthermore, the outer diameter of the upper end of the lower plug is smaller than the outer diameter of the lower end.

[0011] Furthermore, a first lifting part is provided outside the outer mold; and / or A second lifting part is provided on each of the inner mold segments.

[0012] Secondly, a method for die forging a large pump housing with a nozzle is provided, which includes the following steps: Select the type and quantity of steel ingots, and smelt and cast them into billets; The cast blank is repeatedly pulled and pulverized. After the blank is drawn, it is cut into blanks, and then rough turned, positioning holes are machined and flaw detection is performed on the blank. Assemble and bake a large forging die for a pump housing with a nozzle; After roughing, an anti-oxidant is applied to the surface of the billet, which is then sent into a heating furnace for heating. Once the temperature reaches the set temperature, it is kept at a constant temperature. After the billet is taken out of the furnace, it is pre-forged to remove the oxide scale outside the large forging die with nozzle pump casing; After removing the oxide scale, the billet is fed into the inner mold and pressed completely into the inner mold using a forging plate. The blank is pressed into the inner die by the upper punch so that the blank is completely pressed into and fills the forming cavity, thereby obtaining a forging; Remove the inner mold and the forging together from the outer mold, then remove each mold piece and side plug of the inner mold to take out the forging.

[0013] Furthermore, removing the inner mold and the forging together from the outer mold includes: Pull the outer mold upwards from the lower pad; Invert the outer mold to pour the inner mold and forging out of the outer mold together.

[0014] Thirdly, a design method is provided for segmented design of the inner mold in a large forging die for a pump housing with a nozzle. The design method includes the following steps: The mathematical model for segmentation is established, and the formula is as follows:

[0015] in, The chord length of the arc corresponding to the inner mold segmentation; The inner diameter of the inner mold; The number of petals; The diameter of the nozzle forming hole; Using a segmentation mathematical model, Iterate from large to small until the formula of the segmentation mathematical model is fully satisfied to obtain the design value of the number of segments.

[0016] The beneficial effects of this invention are as follows: Compared with traditional free forging, this invention improves the density and microstructure of the large nozzle pump housing under triaxial stress, thus meeting the performance requirements. In this invention, the forging achieves near-net-shape forming, resulting in better product shape and properties synergy, and significantly reduces machining allowance, thereby reducing material consumption and manufacturing costs. This invention employs a segmented combination internal mold technology, using different assembly forms for pump casings with different nozzle distributions to achieve multiple uses of a single mold. This reduces mold investment, expands application scenarios, and improves the flexibility of production organization. Attached Figure Description

[0017] The invention will now be described in more detail with reference to embodiments and the accompanying drawings. Figure 1 A schematic diagram of the forming mold in this invention is shown; Figure 2 A cross-sectional view of the forming mold of the present invention is shown; Figure 3 A schematic diagram showing the use of the forming mold of the present invention is displayed; Figure 4 This diagram shows the blanking rough turning and machining of positioning holes in the forming method of the present invention; Figure 5 This diagram shows a pressing motion during the molding process of the present invention. Figure 6 This diagram illustrates the extrusion forming process in the forming method of the present invention. Figure 7 The relevant dimensional diagrams of the design method in this invention are shown; Figure 8 A schematic diagram of the single-nozzle pump casing is shown. Figure 9 A schematic diagram of the dual-nozzle pump casing is shown. Figure 10 A schematic diagram of the three-nozzle pump casing is shown. Figure 11 A schematic diagram of the four-nozzle pump housing is shown. In the accompanying drawings, the same parts use the same reference numerals. The drawings are not to scale.

[0018] Figure label: 1. Lower backing plate; 2. Outer mold; 3. Inner mold; 301. Forming cavity; 302. Upper punch; 303. Mounting port; 304. Nozzle forming hole; 4. Side plug; 5. Lower plug; 6. Nozzle; 7. Positioning hole; 8. Forging plate; 9. Upper punch; 10. Forging. Detailed Implementation

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] This invention provides a large forging die for pump housing with nozzle, such as... Figure 1-3 As shown, it includes: Lower pad 1; Outer mold 2, which is detachably mounted on the upper end of the lower pad 1; Inner mold 3 is coaxially inserted into the upper part of outer mold 2 from top to bottom. The outer wall of inner mold 3 fits the inner wall of outer mold 2. Inner mold 3 is evenly divided into segments along the circumference. A forming cavity 301 is provided in inner mold 3 for near-net-shape forming of the outer contour of the blank. The main cavity axis of forming cavity 301 coincides with the axis of inner mold 3. Forming cavity 301 is used to near-net-shape form for forging 10. The lower end of the lower plug 5 is engaged with the lower pad 1. The upper end of the lower plug 5 extends vertically through the outer mold 2 and into the forming cavity 301 so that a lower through hole prototype is formed at the lower end of the forging 10 after die forging, which facilitates the subsequent precision machining of the pump housing lower through hole. The side plug 4 has its outer end inserted into the outer side of the inner mold 3 from the outside to the inside, and its outer end face is attached to the inner wall of the outer mold 2. The inner end of the side plug 4 extends inward into the forming cavity 301. The side plug 4 cooperates with the inner mold 3 to form a nozzle 6 on the side of the forged part 10 after die forging, and a nozzle through hole prototype is formed inside the nozzle 6.

[0021] It should be noted that, based on manufacturing process and cost considerations, the inner mold 3 can be made of casting, and the material can be a high-temperature resistant material that also has wear resistance; the outer mold 2 needs to be checked for strength, and the material can be Cr, Mn, or Mo; the lower plug 5 and the side plug 4 can be made of heat-resistant steel or H13, the inner diameter of the side plug 4 can be determined according to the wall thickness of the nozzle 6, and the slope of the side plug 4 can be calculated by the draft force.

[0022] It should also be noted that, since the conventional ejector is blocked by the lower plug 5, the outer mold 2 needs to be flipped over outside the machine during demolding.

[0023] It is understandable that the upper slope of the lower plug 5 and the inner end slope of the side plug 4 can be 2°.

[0024] In one embodiment, the upper outer diameter of the inner mold 3 is larger than the lower outer diameter, and the outer surface of the inner mold 3 is generally frustoconical, so that the outer surface of the inner mold 3 forms a demolding slope; correspondingly, the upper part of the outer mold 2 is provided with a frustoconical hole, and the inner contour size of the frustoconical hole matches the overall outer contour size of the inner mold 3 and the side plug 4.

[0025] In one embodiment, an upper punch 302 is coaxially provided inside the inner mold 3. The upper end of the upper punch 302 extends to the upper end face of the inner mold 3, and the lower end of the upper punch 302 connects to the upper end of the forming cavity 301. The inner diameter of the upper punch 302 matches the outer diameter of the pressure plate of the upper punch 9. Specifically, the draft angle between the inner mold 3 and the outer mold 2 can be 5°~8°. The height of the upper punch 302 can be 200mm, that is, the height difference between the upper end face of the inner mold 3 and the forming cavity 301 is 200mm.

[0026] It is understandable that the upper end face of the inner mold 3 is higher than the forming cavity 301 so that when the lower part of the upper punch 9 is pressed into the forming cavity 301, the pressure plate of the upper punch 9 can enter the upper punch opening 302 to cover the upper end of the forming cavity 301, thereby facilitating the function of the pressure plate of the upper punch 9.

[0027] It should be noted that the lower slope of the upper punch 9 can be 2°.

[0028] In one embodiment, the inner mold 3 is provided with an installation port 303 located outside the forming cavity 301, and the outer end of the side plug 4 is engaged between the installation port 303 and the inner wall of the outer mold 2.

[0029] In one embodiment, the outer end of the side plug 4 is provided with a conformal arc surface for fitting the inner wall of the outer mold 2.

[0030] In one embodiment, the upper outer diameter of the lower plug 5 is smaller than the lower outer diameter, and the upper part of the lower plug 5 is generally frustoconical.

[0031] In one embodiment, since components such as the outer mold 2 and the inner mold 3 are very heavy, a first lifting part is provided outside the outer mold 2 to facilitate the lifting and overturning of the outer mold 2 from the lower end cap 5 using lifting equipment, and a second lifting part is provided on any mold segment of the inner mold 3 to facilitate the lifting and installation of the inner mold 3.

[0032] The present invention also provides a method for forging a large pump housing with a nozzle, which includes the following steps: Steel ingot casting: Select the type and quantity of steel ingots according to the requirements of forging 10, and smelt and cast them into billets; Bar forging: repeatedly drawing and rolling the cast billet to solve the problem of the required "property" of the workpiece; Rough turning, machining of positioning holes 7, and flaw detection: Determine the blanking dimensions based on the required metal quantity of forging 10 to blank the drawn billet, such as... Figure 4As shown, the blank is rough-turned, the positioning holes 7 are machined, and the flaw is detected after cutting. Among them, the blank is peeled off by rough turning, which can meet the requirements of natural mold entry and also facilitate the application of anti-oxidation agent to reduce oxide scale. Mold assembly and baking: Assemble inner molds 3 of different models and specifications according to the number of product nozzles 6, and then bake the forming mold; the baking temperature is controlled at about 300℃; and lubricant is applied to the mold before the blank is put into the mold. Billet heating: After rough turning, the surface of the billet is coated with an anti-oxidant and then sent into the heating furnace for heating. After the temperature reaches 1200℃, it is kept at a uniform temperature. Pre-upsetting and descaling: The furnace exit temperature of the billet is controlled at around 1200℃. After the billet exits the furnace, it is pre-upset outside the mold to remove the oxide scale. Pressing into the mold: such as Figure 5 As shown, the billet after removing the oxide scale is quickly fed into the inner mold 3 and the billet is completely pressed into the inner mold 3 using a flat anvil or forging plate 8. Extrusion molding: such as Figure 6 As shown, the upper punch 9 is used to extrude the metal blank in the inner die 3 at a stable speed so that the blank is completely pressed into and fills the forming cavity 301, thereby obtaining the forging 10; Demolding and part removal: After extrusion is completed, the inner mold 3 and the forging 10 are removed together from the outer mold 2. Then, the mold segments of the inner mold 3 and the side plugs 4 are removed to take out the forging 10.

[0033] It should be noted that the forging plate 8 and the upper punch 9 can be switched to be directly above the forming die via the double slide rail double station pad to improve the forging efficiency.

[0034] In one embodiment, removing the inner mold 3 and the forging 10 together from the outer mold 2 includes: Pull the outer mold 2 upward from the lower pad 1; Invert the outer mold 2 so that the inner mold 3 and the forging 10 are poured out together from the outer mold 2.

[0035] This invention also provides a design method for segmenting the inner mold 3 in a large nozzle pump housing forging die, such as... Figure 7 and Figure 8 As shown, the design method includes the following steps: The mathematical model for segmentation is established, and the formula is as follows:

[0036] in, The chord length of the arc corresponding to the three segments of the inner mold; The inner diameter of inner mold 3; The number of petals; The diameter of the nozzle forming hole is 304 and is the main variable; Using a segmentation mathematical model, Iterate from large to small until the formula of the segmentation mathematical model is fully satisfied to obtain the design value of the number of segments.

[0037] When establishing the mathematical model for segmentation, the nozzle forming hole 304 is located in the middle of the mold segment by default.

[0038] It should be noted that, The edge thickness of the nozzle forming hole 304 is required to ensure the strength at the nozzle forming hole 304 after the inner mold is divided into three sections. ; Considering the manufacturability of the component after segmentation, the number of segments should be greater than 3, that is... .

[0039] It should also be noted that, due to the number of petals The smaller the size, the heavier each lobe is, and the more lobes there are. The larger the size, the lighter each mold segment is, and the lighter the mold segments are, the easier they are to process. Iterate from large to small.

[0040] The following is an example of a three-part inner mold design in a forming die: Inner diameter of inner mold 3 The nozzle forming hole is 304mm in diameter and has a diameter of 2080mm. It is 650mm; Generally This time, we'll use 350mm. Will Iterate from large to small, gradually decreasing the number of iterations: Cut into 6 parts, that is It is 6. That is 1040mm. The value is 195mm and less than 350mm, therefore it does not fully meet the requirements; Cut into 5 parts, that is It is 5. That is approximately 1222mm. It is approximately 286mm and less than 350mm, therefore it does not fully meet the requirements; Cut into 4 parts, that is It is 4. That is approximately 1470mm. The diameter is approximately 410mm and greater than 350mm, thus fully satisfying the formula of the segmentation mathematical model. The design value of the number of segments is 4. Therefore, this example is segmented into 4 segments while satisfying the strength of the 304 sidewall of the nozzle forming hole.

[0041] Furthermore, since the inner mold 3 adopts a segmented assembly structure, various circumferential uniform distribution patterns of the nozzle 6 can be planned using a segmentation mathematical model based on the different diameters of the nozzle forming holes 304. This also adapts to situations such as... Figure 9-11The design of the pump housing (cylinder) with multiple nozzles 6 shown also realizes the multi-purpose use of one mold.

[0042] In the description of this invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0043] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A large forging die for a pump housing with a nozzle, characterized in that, include: Lower pad (1); Outer mold (2), the outer mold (2) is detachably disposed at the upper end of the lower pad (1); Inner mold (3), the inner mold (3) is placed into the upper part of the outer mold (2) from top to bottom, the outer wall of the inner mold (3) is attached to the inner wall of the outer mold (2), the inner mold (3) is evenly divided into segments along the circumference, and a forming cavity (301) for near-net-shape forming of the outer contour of the blank is provided in the inner mold (3). The lower end of the ... Side plug (4), the outer end of the side plug (4) is inserted into the outer side of the inner mold (3) from the outside to the inside and the outer end face is attached to the inner wall of the outer mold (2), and the inner end of the side plug (4) extends into the forming cavity (301).

2. The large-scale pump housing forging die according to claim 1, characterized in that, The outer diameter of the upper end of the inner mold (3) is larger than the outer diameter of the lower end.

3. The large-scale pump housing forging die according to claim 1, characterized in that, The inner mold (3) is coaxially provided with an upper punch (302), the upper end of the upper punch (302) extends to the upper end face of the inner mold (3), the lower end of the upper punch (302) is connected to the upper end of the forming cavity (301), and the inner diameter of the upper punch (302) matches the outer diameter of the pressure plate of the upper punch (9).

4. The large-scale pump housing forging die according to claim 1, characterized in that, The inner mold (3) is provided with an installation port (303) located outside the forming cavity (301), and the outer end of the side plug (4) is engaged between the installation port (303) and the inner wall of the outer mold (2).

5. The large-scale pump housing forging die according to claim 4, characterized in that, The outer end of the side plug (4) is provided with a conformal arc surface for fitting the inner wall of the outer mold (2).

6. The large-scale pump housing forging die according to claim 1, characterized in that, The upper outer diameter of the lower plug (5) is smaller than the lower outer diameter.

7. The large-scale pump housing forging die according to claim 1, characterized in that, The outer mold (2) is provided with a first lifting part; and / or A second hoisting part is provided on each of the mold segments of the inner mold (3).

8. A method for die forging a large pump housing with a nozzle, characterized in that, Includes the following steps: Select the type and quantity of steel ingots, and smelt and cast them into billets; The cast blank is repeatedly pulled and pulverized. After the blank is cut, rough turning, positioning holes (7) and flaw detection are performed on the blank. Assemble and bake the large nozzle pump housing forging die as described in any one of claims 1-7; After roughing, an anti-oxidant is applied to the surface of the billet, which is then sent into a heating furnace for heating. Once the temperature reaches the set temperature, it is kept at a constant temperature. After the billet is taken out of the furnace, it is pre-forged to remove the oxide scale outside the large forging die with nozzle pump casing; After removing the oxide scale, the billet is fed into the inner mold (3) and pressed completely into the inner mold (3) by the forging plate (8). The upper punch (9) is used to press the blank in the inner die (3) so that the blank is completely pressed into and fills the forming cavity (301), thereby obtaining the forging (10). Remove the inner mold (3) and the forging (10) together from the outer mold (2), and then remove each mold piece and side plug (4) of the inner mold (3) to remove the forging (10).

9. The forming method according to claim 8, characterized in that, The step of removing the inner mold (3) and the forging (10) together from the outer mold (2) includes: Pull the outer mold (2) upward from the lower pad (1); Invert the outer mold (2) to pour the inner mold (3) and the forging (10) out of the outer mold (2) together.

10. A design method for segmenting the inner mold (3) in the large nozzle pump housing forging die according to any one of claims 1-7, characterized in that, The design method includes the following steps: The mathematical model for segmentation is established, and the formula is as follows: in, The chord length of the arc corresponding to the inner mold (3) after it is divided into segments; The inner diameter of the inner mold (3); The number of petals; The diameter of the nozzle forming hole (304); Using a segmentation mathematical model, Iterate from large to small until the formula of the segmentation mathematical model is fully satisfied to obtain the design value of the number of segments.

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