A method for casting a ball valve housing

Abstract

The application provides a ball valve shell casting method and relates to the technical field of casting. The ball valve shell casting method comprises the following steps: modeling a split surface of a ball valve shell with the split surface facing upward and taking the split surface as a parting surface; dividing the ball valve shell into an axle hole area, a ball shell area, an end face flange area and a support base area; setting risers on the axle hole area, the ball shell area, the end face flange area and the support base area respectively, setting a first chill on the outer periphery of the axle hole area, setting a second chill between the ball shell area and the end face flange area, setting a third chill on the end face flange area and setting a fourth chill on the axle hole area; setting a pouring system and then pouring. The application can improve production efficiency and ensure casting quality.

Description

Technical Field

[0001] This invention relates to the field of casting technology, and more specifically, to a method for casting a ball valve body. Background Technology

[0002] As a core pressure-bearing component in a hydroelectric ball valve system, the valve body typically comprises a shaft bore, end flange, ball shell, and support base. It is usually manufactured using casting processes. In related technologies, to improve the production efficiency of the ball valve body, a segmented design with the segmented side facing upwards is often used during casting. However, this results in the thick shaft bore structure being located at the bottom and the thin-walled ball shell at the top. This affects the solidification effect, increases shrinkage cavities and porosity defects, and consequently impacts the casting quality. Summary of the Invention

[0003] The problem this invention addresses is: how to improve production efficiency while ensuring casting quality.

[0004] To address the above problems, this invention provides a method for casting a ball valve body, wherein the ball valve body includes a shaft hole, a ball shell, an end flange, and a support base; the method for casting the ball valve body includes the following steps: The ball valve body is shaped with the split surface facing upwards, and the split surface is used as the parting surface. The ball valve body is divided into a shaft hole area, a ball shell area, an end face flange area, and a support base area. The shaft hole area includes the shaft hole and an annular area adjacent to the shaft hole in the ball shell. The ball shell area includes a central area in the ball shell located between the annular area and the split surface. The end face flange area includes an edge area in the end face flange and the ball shell located between the central area and the end face flange. The support base area includes the support base. Riser is provided on the shaft hole area, the spherical shell area, the end face flange area and the support base area respectively; a first chill is provided on the outer periphery of the shaft hole area; a second chill is provided between the spherical shell area and the end face flange area; a third chill is provided on the end face flange area; and a fourth chill is provided on the shaft hole area. Set up the gating system, and then pour the gating.

[0005] Optionally, the width of the annular region is three times the wall thickness of the spherical shell, and the width of the edge region is twice the wall thickness of the spherical shell.

[0006] Optionally, providing risers in the shaft hole area, the spherical shell area, the end face flange area, and the support base area respectively includes: A first concealed riser is provided in the shaft hole area, a second concealed riser is provided in the spherical shell area, an exposed riser is provided in the end face flange area, and a third concealed riser is provided in the support base area.

[0007] Optionally, the end face flange area is provided with two exposed risers, and the two exposed risers are located at both ends of the end face flange area along the extension direction.

[0008] Optionally, multiple first chills are sequentially arranged along the outer periphery of the shaft hole area; multiple second chills are sequentially arranged at the connection between the spherical shell area and the end face flange area, and the arrangement direction of the multiple second chills is parallel to the end face of the end face flange area.

[0009] Optionally, the third chill is located at the middle of the end face flange area along the extension direction.

[0010] Optionally, before setting up the gating system and then performing the pouring, the method further includes: A first process subsidy is provided on the inner wall of the shaft hole area, a second process subsidy is provided on the inner wall surface of the spherical shell area, a third process subsidy is provided on the outer end face of the end face flange area, and a fourth process subsidy is provided on the side of the support base area away from the spherical shell area.

[0011] Optionally, the sum of the thickness of the second process patch and the thickness of the spherical shell is greater than 1.15 times the thickness of the spherical shell, and the circumferential dimension of the second process patch along the end face flange is 3-4 times the sum of the thickness of the second process patch and the thickness of the spherical shell.

[0012] Optionally, the sum of the thickness of the third process patch and the thickness of the end face flange is greater than 1.2 times the thickness of the end face flange, and the circumferential dimension of the third process patch along the end face flange is less than or equal to 4 times the sum of the thickness of the third process patch and the thickness of the end face flange.

[0013] Optionally, the gating system adopts an open bottom return port with an open ratio greater than 1:2, and the inner gating channel of the gating system is located at the bottom end of the ball valve body.

[0014] The beneficial effects of the ball valve shell casting method of the present invention are as follows: On the one hand, by molding the ball valve shell with the split surface facing upwards and using the split surface as the parting surface, compared with the scheme where the split surface faces downwards, the outer surface of the casting is prevented from facing upwards. This avoids the accumulation of floating oxide slag, loose molding sand, and other inclusions on the outer surface of the casting, thereby reducing the amount of finishing and shaping work and improving production efficiency. On the other hand, by setting a first chill on the outer periphery of the shaft hole area and a second chill between the ball shell area and the end flange area, the ball shell area can be effectively separated from the shaft hole area and the end flange area into independent feeding areas. Combined with the risers in each area, each area can solidify sequentially from the chill to the riser, ensuring that each area receives sufficient feeding and that the overall feeding of the casting is good, thereby ensuring casting quality. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the ball valve shell according to an embodiment of the present invention; Figure 2 This is a cross-sectional schematic diagram of the ball valve shell according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the partitioned feeding method for casting the ball valve body according to an embodiment of the present invention; Figure 4 This is a cross-sectional view of the feeding scheme in the ball valve body casting method of this invention.

[0016] Explanation of reference numerals in the attached figures: 1-Shaft hole; 2-Spherical shell; 21-Annular area; 22-Central area; 23-Edge area; 3-End face flange; 4-Support base; 5-Split face; 6-Shaft hole area; 61-First chill; 62-First concealed riser; 63-First process patch; 64-Fourth chill; 7-Spherical shell area; 71-Second chill; 72-Second concealed riser; 73-Second process patch; 8-End face flange area; 81-Third chill; 82-Open riser; 83-Third process patch; 9-Support base area; 91-Third concealed riser; 92-Fourth process patch; 10-Insulation board. Detailed Implementation

[0017] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0018] In the attached figures, the X-axis represents the front-to-back position, with the positive direction of the X-axis representing the front and the negative direction representing the rear. The Y-axis represents the left-to-right position, with the positive direction representing the left and the negative direction representing the right. The Z-axis represents the up-down position, with the positive direction representing the top and the negative direction representing the bottom. It should be noted that the aforementioned representations of the X, Y, and Z axes are for ease of description and simplification of the invention, 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 the invention.

[0019] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0020] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0021] This invention provides a method for casting a ball valve body, which will be described in detail below with reference to specific embodiments.

[0022] like Figures 1 to 4 As shown in the figure, an embodiment of the present invention provides a method for casting a ball valve body, which is used to cast a ball valve body. The ball valve body includes a shaft hole 1, a ball shell 2, an end flange 3, and a support base 4. The method for casting the ball valve body includes the following steps: The ball valve body is shaped with the split surface 5 facing upwards, and the split surface 5 is used as the parting surface. The ball valve body is divided into a shaft hole area 6, a ball shell area 7, an end face flange area 8, and a support base area 9. The shaft hole area 6 includes an annular area 21 adjacent to the shaft hole 1 in the shaft hole 1 and the ball shell 2. The ball shell area 7 includes a central area 22 in the ball shell 2 located between the annular area 21 and the split surface 5. The end face flange area 8 includes an edge area 23 in the end face flange 3 and the ball shell 2 located between the central area 22 and the end face flange 3. The support base area 9 includes the support base 4. Risers are provided on the shaft hole area 6, the spherical shell area 7, the end face flange area 8 and the support base area 9 respectively. A first chill 61 is provided on the outer periphery of the shaft hole area 6. A second chill 71 is provided between the spherical shell area 7 and the end face flange area 8. A third chill 81 is provided on the end face flange area 8. A fourth chill 64 is provided on the shaft hole area 6. Set up the gating system, and then pour the gating.

[0023] It should be noted that the riser is a specially designed cavity in the mold to store high-temperature molten metal. The molten metal inside solidifies later than the valve body, thus allowing it to be transported to the shrinking valve body under gravity, filling the voids created by the shrinkage. The chill, placed in the mold, utilizes its excellent thermal conductivity to accelerate the solidification rate of the corresponding area. It should also be noted that the molding can be done using a sand mold of a full-size sample.

[0024] In this embodiment, on the one hand, by shaping the ball valve body with the split surface 5 facing upwards and using the split surface 5 as the parting surface, compared to the scheme where the split surface 5 faces downwards, the outer surface of the casting is prevented from facing upwards. This avoids the accumulation of floating oxide slag, loose molding sand, and other inclusions on the outer surface of the casting, thereby reducing the amount of finishing and shaping work and improving production efficiency. On the other hand, a first chill 61 is set on the outer periphery of the shaft hole area 6, and a second chill 71 is set between the ball shell area 7 and the end face flange area 8. This can effectively separate the ball shell area 7 from the shaft hole area 6 and the end face flange area 8 into independent feeding areas. Combined with the risers in each area, each area can solidify sequentially from the chill to the riser, ensuring that each area receives sufficient feeding and that the overall feeding of the casting is good, thereby ensuring casting quality.

[0025] It should be noted that, as Figure 2 As shown, the support base 4 has a downward cavity, which is not easy to demold. Therefore, it can be opened separately or made into movable material with polystyrene board to ensure that the support base 4 is easy to demold and easy to core during the molding process.

[0026] It should be noted that for large ball valve shell cast steel parts with an outer diameter of 3-4.5m, the model scale of the 7th region of the ball shell is 1.2% to 0.9%, and the model scale of the other regions is 2.2%.

[0027] Optionally, such as Figure 3 As shown, the width of the annular region 21 is three times the wall thickness of the spherical shell 2, and the width of the edge region 23 is twice the wall thickness of the spherical shell 2.

[0028] Optionally, such as Figure 3 As shown, the provision of risers in the shaft hole area 6, the spherical shell area 7, the end face flange area 8, and the support base area 9 includes: A first concealed riser 62 is provided on the shaft hole area 6, a second concealed riser 72 is provided on the spherical shell area 7, an exposed riser 82 is provided on the end face flange area 8, and a third concealed riser 91 is provided on the support base area 9.

[0029] Specifically, the first concealed riser 62 and the open riser 82 can be cylindrical risers, while the second concealed riser 72 and the third concealed riser 91 can be waist-shaped column risers.

[0030] In this optional embodiment, strict partitioning and shrinkage are achieved through the first dark riser 62, the second dark riser 72, the open riser 82 and the third dark riser 91, which can effectively guarantee the shrinkage effect of each zone.

[0031] It should be noted that insulation plates 10 can be installed around the first concealed riser 62, the second concealed riser 72, the open riser 82 and the third concealed riser 91 respectively to improve the feeding efficiency of the risers and reduce the amount of molten steel used.

[0032] Optionally, such as Figure 3 As shown, the end flange area 8 is provided with two exposed risers 82, and the two exposed risers 82 are located at both ends of the end flange area 8 along the extension direction.

[0033] It is understandable that the end flange area 8 is a U-shaped structure. If an exposed riser 82 is only provided at one end of the end flange area 8 along the extension direction (one end of the U-shaped structure), the other end will not be effectively covered during the feeding process, causing shrinkage cavities and porosity defects. Therefore, in this optional embodiment, by providing two exposed risers 82 in the end flange area 8 and placing the two exposed risers 82 at both ends of the end flange area 8 along the extension direction, it can be ensured that the feeding process is carried out synchronously from both ends to the end flange area 8, effectively preventing shrinkage cavities and porosity.

[0034] Optionally, such as Figure 3 As shown, multiple first chills 61 are arranged sequentially along the outer periphery of the shaft hole area 6; multiple second chills 71 are arranged sequentially at the connection between the spherical shell area 7 and the end face flange area 8, and the arrangement direction of the multiple second chills 71 is parallel to the end face of the end face flange area 8.

[0035] It should be noted that multiple first chills 61 can be arranged around the shaft hole area 6 to roughly form a ring structure, and the first chills 61 can be arranged at equal or unequal intervals; this embodiment does not impose any restrictions. In addition, there are two spherical shell areas 7, and the end face flange area 8 has one connection position with each of the two spherical shell areas 7. Multiple second chills 71 can be arranged at each connection position, and the arrangement direction of the multiple second chills 71 is parallel to the end face of the end face flange area 8.

[0036] In this optional embodiment, the quenching effect of the multiple first chills 61 and multiple second chills 71 using the quenching device can effectively cut off the thermodynamic channels between the shaft hole area 6, the spherical shell area 7, and the end flange area 8, preventing them from competing for molten steel, ensuring that each area forms a strict sequential solidification towards the riser direction, and improving casting quality.

[0037] Optionally, such as Figure 3 As shown, the third chill 81 is located in the middle of the end face flange area 8 along the extension direction.

[0038] Specifically, two third chills 81 can be installed in the middle of the end flange area 8 along the extension direction.

[0039] In this optional embodiment, by providing a third chill 81 in the middle of the end flange area 8 along the extension direction, the thermodynamic channel in the end flange area 8 can be cut off from the middle, so that independent feeding areas are formed on both sides of the end flange area 8, thereby improving the feeding and solidification effect.

[0040] Optionally, such as Figure 3 and Figure 4 As shown, before setting up the gating system and then pouring, the process further includes: A first process affix 63 is provided on the inner wall of the shaft hole area 6, a second process affix 73 is provided on the inner wall surface of the spherical shell area 7, a third process affix 83 is provided on the outer end face of the end face flange area 8, and a fourth process affix 92 is provided on the side of the support base area 9 away from the spherical shell area 7.

[0041] It should be noted that the process subsidy is a process structure that is artificially thickened at the end of the corresponding region near the riser to establish a temperature gradient that increases toward the riser.

[0042] In this optional embodiment, four process subsidies are used to achieve localized thickening of each zone, which can extend and expand the flow channels of molten metal, ensuring that the molten metal from the riser can smoothly replenish the interior of the casting, thereby making the feeding more sufficient. In addition, since the third process subsidy 83 is set on the outer end face of the end flange area 8, it is convenient to cut and remove the subsidy during post-casting cleaning, without reducing the bearing area of ​​the core head of the inner cavity sand core.

[0043] Optionally, such as Figure 4 As shown, the sum of the thickness of the second process patch 73 and the thickness of the spherical shell 2 is greater than 1.15 times the thickness of the spherical shell 2, and the circumferential dimension of the second process patch 73 along the end face flange 3 is 3-4 times the sum of the thickness of the second process patch 73 and the thickness of the spherical shell 2.

[0044] In this optional embodiment, by making the sum of the thickness of the second process patch 73 and the spherical shell 2 greater than 1.15 times the thickness of the spherical shell 2, the thicknesses of the unpatched spherical shell 2, the patched spherical shell 2, and the riser can vary in a stepwise manner from thin to thick, thereby creating a feeding channel that facilitates feeding and ensures good overall feeding of the casting. Furthermore, the circumferential dimension of the second process patch 73 along the end face flange 3 is 3-4 times the sum of the thicknesses of the second process patch 73 and the spherical shell 2, thus ensuring the effectiveness of the patch.

[0045] Optionally, such as Figure 3 As shown, the sum of the thicknesses of the third process patch 83 and the end face flange 3 is greater than 1.2 times the thickness of the end face flange 3, and the circumferential dimension of the third process patch 83 along the end face flange 3 is less than or equal to 4 times the sum of the thicknesses of the third process patch 83 and the end face flange 3.

[0046] In this optional embodiment, by making the sum of the thickness of the third process patch 83 and the end face flange 3 greater than 1.2 times the thickness of the end face flange 3, the thicknesses of the unpatched end face flange 3, the patched end face flange 3, and the riser can vary in a stepwise manner from thin to thick, thereby creating a feeding channel that facilitates feeding and ensures good overall feeding of the casting. Furthermore, the circumferential dimension of the third process patch 83 along the end face flange 3 is less than or equal to four times the sum of the thicknesses of the third process patch 83 and the end face flange 3, thus ensuring the effectiveness of the patch.

[0047] Optionally, the gating system adopts an open bottom return port with an open ratio greater than 1:2, and the inner gating channel of the gating system is located at the bottom end of the ball valve body.

[0048] Optionally, before pouring, the air inside the mold can be replaced with a protective gas, such as argon, to prevent secondary oxidation of the molten metal and avoid oxidation inclusions.

[0049] Optionally, the rising speed of the molten steel surface in the mold during the casting process is controlled at 20-30 mm / s. This allows the molten steel to fill smoothly from bottom to top, avoiding the formation of porosity and oxide inclusions due to turbulence in the molten steel.

[0050] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for casting a ball valve body, characterized in that, For casting ball valve bodies, the ball valve body includes a shaft hole (1), a ball shell (2), an end flange (3), and a support base (4); the ball valve body casting method includes the following steps: The ball valve body is shaped with the split surface (5) facing upwards, and the split surface (5) is used as the parting surface; The ball valve body is divided into a shaft hole area (6), a ball shell area (7), an end face flange area (8), and a support base area (9). The shaft hole area (6) includes an annular area (21) adjacent to the shaft hole (1) and the ball shell (2). The ball shell area (7) includes a central area (22) in the ball shell (2) located between the annular area (21) and the split surface (5). The end face flange area (8) includes an edge area (23) in the end face flange (3) and the ball shell (2) located between the central area (22) and the end face flange (3). The support base area (9) includes the support base (4). Riser is provided on the shaft hole area (6), the spherical shell area (7), the end face flange area (8) and the support base area (9). A first chill (61) is provided on the outer periphery of the shaft hole area (6). A second chill (71) is provided between the spherical shell area (7) and the end face flange area (8). A third chill (81) is provided on the end face flange area (8). A fourth chill (64) is provided on the shaft hole area (6). Set up the gating system, and then pour the gating.

2. The ball valve body casting method according to claim 1, characterized in that, The width of the annular region (21) is three times the wall thickness of the spherical shell (2), and the width of the edge region (23) is twice the wall thickness of the spherical shell (2).

3. The ball valve body casting method according to claim 1, characterized in that, The provision of risers in the shaft hole area (6), the spherical shell area (7), the end face flange area (8), and the support base area (9) includes: A first concealed riser (62) is provided in the shaft hole area (6), a second concealed riser (72) is provided in the spherical shell area (7), an exposed riser (82) is provided in the end face flange area (8), and a third concealed riser (91) is provided in the support base area (9).

4. The ball valve body casting method according to claim 3, characterized in that, The end flange area (8) is provided with two open risers (82), and the two open risers (82) are located at both ends of the end flange area (8) along the extension direction.

5. The ball valve body casting method according to claim 1, characterized in that, Multiple first chills (61) are arranged sequentially along the outer periphery of the shaft hole area (6); multiple second chills (71) are arranged sequentially at the connection between the spherical shell area (7) and the end face flange area (8), and the arrangement direction of the multiple second chills (71) is parallel to the end face of the end face flange area (8).

6. The ball valve body casting method according to claim 1, characterized in that, The third chill (81) is located in the middle of the end face flange area (8) along the extension direction.

7. The ball valve body casting method according to claim 1, characterized in that, Before setting up the gating system and then pouring, the process also includes: A first process patch (63) is provided on the inner wall of the shaft hole area (6), a second process patch (73) is provided on the inner wall surface of the spherical shell area (7), a third process patch (83) is provided on the outer end face of the end face flange area (8), and a fourth process patch (92) is provided on the side of the support base area (9) away from the spherical shell area (7).

8. The ball valve body casting method according to claim 7, characterized in that, The sum of the thickness of the second process patch (73) and the spherical shell (2) is greater than 1.15 times the thickness of the spherical shell (2), and the circumferential dimension of the second process patch (73) along the end face flange (3) is 3-4 times the sum of the thickness of the second process patch (73) and the spherical shell (2).

9. The ball valve body casting method according to claim 8, characterized in that, The sum of the thickness of the third process patch (83) and the end face flange (3) is greater than 1.2 times the thickness of the end face flange (3), and the circumferential dimension of the third process patch (83) along the end face flange (3) is less than or equal to 4 times the sum of the thickness of the third process patch (83) and the end face flange (3).

10. The ball valve body casting method according to claim 1, characterized in that, The gating system adopts an open bottom return port with an open ratio greater than 1:2, and the inner gating channel of the gating system is located at the bottom end of the ball valve body.

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