A volute casting with flange and manufacturing process

Abstract

The application provides a volute casting with a flange, which comprises a volute body and a flange body, the volute body comprises a spiral shell with a buffer neck, an outflow connecting disc and an inflow connecting disc, the buffer neck extends along the tangent direction of the outer circle of the spiral shell, the spiral shell is internally provided with a spiral flow channel, a buffer cavity is formed in the buffer neck, the buffer cavity penetrates into the spiral flow channel, the inflow connecting disc is connected to one end of the spiral shell, the surface of the inflow connecting disc is provided with an inflow port, the inflow port penetrates into the spiral flow channel, the spiral shell is provided with an inflow hole at the other end of the inflow port, the lower end of the flange body is connected to the outer side of the inflow hole of the spiral shell, the spiral flow channel is communicated with the inner cavity of the flange body through the inflow hole, the outflow connecting disc is connected to the end face of the buffer neck, the surface of the outflow connecting disc is provided with an outflow port, and the outflow port penetrates into the buffer cavity; the integrated flange body arranged on the volute solves the sealing problem caused by the threaded assembly between the volute and the flange, and improves the air tightness between the flange and the volute.

Description

Technical Field

[0001] This invention belongs to the field of casting production technology, especially the production of volute castings, specifically relating to a flanged volute casting and its manufacturing process. Background Technology

[0002] The volute is short for volute-type water inlet chamber. Its shape resembles a snail shell, hence the common name "volute." To ensure uniform water supply to the water guiding mechanism, the cross-section of the volute gradually decreases. Simultaneously, it creates necessary circulation before the water guiding mechanism to reduce its workload.

[0003] In the use of volute casings, a flange is often installed at the liquid inlet end of the volute casing with screws to seal the liquid flow. However, due to the individual assembly of the volute casing and the flange, poor sealing is easy to occur, which affects the power of the volute casing to supply water evenly, and may even cause the volute casing to leak. However, since the casting process of the volute casing casting is relatively complicated with the existing technology, the volute casing and the flange can only be cast separately, and then fixed together by threads after precision machining.

[0004] Patent application number CN202110201493.5 describes a method for casting a volute-shaped part, comprising the following steps: preparing a water-soluble core mold according to design drawings, the water-soluble core mold having a support platform A; bonding wax material to the surface of the water-soluble core mold to form a wax model, the support platform A forming a process hole A on the wax model; bonding molding sand to the surface of the wax model to form a shell, the process hole A forming a support platform B on the shell; firing the shell; pouring molten metal material into the shell, and obtaining a preliminary casting after the metal material solidifies, the support platform B forming a process hole B on the preliminary casting; sealing and filling the process hole B to obtain the finished casting. Using this invention, the support platform B supports the casting, preventing breakage. The corresponding process hole B on the shell allows air trapped in the metal material to escape, ensuring the metal material fills the entire cavity of the shell, thus laying the foundation for improving the casting quality.

[0005] Although the aforementioned patent increases the support during volute casting by adding support platforms A and B to improve the casting quality of volute castings, it is too complex for volute structures with integral flange casting. The forming method of the aforementioned patent is difficult to use to cast such complex volute structures according to design requirements. Summary of the Invention

[0006] The present invention aims to solve the problems mentioned in the background art, and to this end, provides a flanged volute casting and its manufacturing process.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] A flanged volute casting includes a volute body and a flange body. The volute body includes a spiral shell with a buffer neck, an outlet connecting plate, and an inlet connecting plate. The buffer neck extends tangentially to the outer circumference of the spiral shell. A spiral flow channel is formed inside the spiral shell. A flow-slowing cavity is formed along the inner edge of the buffer neck, extending into the spiral flow channel. The inlet connecting plate is connected to one end of the spiral shell. An inlet port is formed on the surface of the inlet connecting plate, extending into the spiral flow channel. An inlet hole is formed at the other end of the spiral shell near the inlet port. The lower end of the flange body is connected to the spiral shell outside the inlet hole. The spiral flow channel communicates with the inner cavity of the flange body through the inlet hole. The outlet connecting plate is connected to the end face of the buffer neck. An outlet port is formed on the surface of the outlet connecting plate, extending into the flow-slowing cavity.

[0009] Preferably, a sealing disc is provided at the upper end of the flange body, and a flange opening is provided on the surface of the sealing disc, which extends along the inner cavity of the flange body to the inlet hole.

[0010] Preferably, the outflow connecting plate, buffer neck, spiral shell, inflow connecting plate, flange body and sealing plate are all integrally formed.

[0011] Preferably, the outflow connecting plate, the inflow connecting plate, and the sealing plate are all integrally formed with several mounting ears on their sides.

[0012] Preferably, the diameter of the inlet is the maximum position diameter of the spiral channel.

[0013] Preferably, the diameter of the inlet hole is smaller than the diameter of the inlet port.

[0014] A manufacturing process for a flanged volute casting, the manufacturing process comprising the following steps:

[0015] S1. Making wax molds:

[0016] S1-1, Core making: Using a special core making mold, the wax core of the volute body is made with water-soluble wax according to the shape and size of the spiral flow channel and the slow flow cavity;

[0017] S1-2. Manufacturing the volute body wax model: Place the wax core in the middle of a special volute mold and fix it. Close the mold and inject wax into the volute mold using a wax injection machine. After cooling, remove the volute wax model and place it in a citric acid aqueous solution to melt the wax core, thus obtaining the volute body wax model.

[0018] S1-3. Manufacturing flange body wax film: Inject wax into the flange body mold using a wax injection machine, remove it after cooling, and obtain the flange body wax mold;

[0019] S2-1, Splicing Wax Model: The flange wax model is installed according to the design requirements and is glued to the corresponding position of the volute body wax model. After the two wax models are connected and tightened, the gap at the connection is filled with wax to obtain the volute wax model with flange.

[0020] S2-2, Auxiliary splicing components: The middle round gate is glued to the inlet of the flanged volute wax mold, and three flange gates are glued to the surface of the inlet connecting plate of the flanged volute wax mold. After the middle round gate and the three flange gates are connected and tightened, the gaps at the connection are filled with wax to obtain the volute assembly.

[0021] S3, Assembly: Weld the main runner of the disc above the above-mentioned central circular gate and three flange gates. Weld the side runner and the main runner of the outlet on the side of the main runner at both ends of the outer side of the buffer neck. Weld the side runner and the main runner of the outlet to both ends of the outer side of the buffer neck through two cross gate bars. After the assembly is completed, use light to inspect and repair the gaps of the assembly with wax to obtain the volute wax module.

[0022] S4. Shell making: After cleaning the volute wax model until it is free of oil and wax residue and air-drying it, the surface of the volute wax model is coated with paint and sand. The first layer is zircon mortar, and the remaining 5 layers are mullite mortar. Before the 2nd, 3rd and 4th layers are sanded, silica sol is applied and air-dried.

[0023] S5. Dewaxing and dehydration: After the air-dried volute wax mold is completely melted in a steam furnace, it is heated to 1200℃ and held for 40-50 minutes to remove excess wax and moisture, thus obtaining a sand shell.

[0024] S6. Casting: A regenerative natural gas roasting furnace is used to prepare the furnace charge. The roasting temperature is required to be 1100℃-1200℃. After the molten steel is tapped, molten steel is poured into multiple gating channels corresponding to the sand shell. The steel is poured to the riser and placed in a sand pile to cool, thus obtaining the mold shell.

[0025] S7. Finishing: Remove the sand shell outside the mold shell and shot blast, requiring 0.4mm steel shot for 15-20 minutes to obtain the volute housing casting.

[0026] S8. Removal of sprues and gates: Use a plasma cutter to cut the sprues and three flange gates of the volute assembly casting, and use a drill press to drill out the central round gate to obtain a semi-finished casting.

[0027] S9. Inspection and Repair: Use light inspection and endoscope to check for gaps and sand holes in the semi-finished castings. Repair the defective parts with argon arc welding, and then use shot blasting machine to polish the flow channels and surface to remove residual sand, dirt and oxide layer polishing marks.

[0028] S10. Final inspection and warehousing: The dimensions and appearance meet the requirements of the drawings. The parts are cleaned, packaged and put into storage to obtain the volute casting with flange.

[0029] Preferably, in step S4, the temperature requirement for each drying cycle is 20℃-25℃, the humidity gradually decreases, and the air speed for drying increases.

[0030] Preferably, the raw materials for the molten steel in step S6 include at least 304 furnace charge, high chromium, nickel plate, ferrosilicon and metallic manganese.

[0031] Preferably, step S10 further includes:

[0032] S10-1, Pressure test: Pass the airtightness test, and the allowable leakage rate is 20 cm³ / min at 1.5 bar.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1. Structurally, the present invention sets the flange body as an integrally formed structure, so that when the volute is assembled and used, only the assembly sealing of the flange sealing plate needs to be ensured, thereby improving the sealing performance of the volute assembly and use, and ensuring that the volute has uniform water supply force and sufficient water supply power.

[0035] 2. In terms of process, this invention splices the volute wax model and the flange wax model, and then welds different casting channels on the outside of the wax model assembly according to the design requirements to ensure the uniformity and completeness of the molten steel during casting. In addition, the shell is made by coating and covering with a single layer of zircon sand and five layers of mullite sand, and then air-drying naturally under conditions of no ventilation and humidity. This gives the volute wax model assembly a sand shell with good strength and thickness during casting to ensure the stability of casting and prevent the sand shell from cracking and affecting the casting quality of the volute casting. Attached Figure Description

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0037] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention;

[0038] Figure 2 This is a front view of an embodiment of the present invention;

[0039] Figure 3 This is a cross-sectional view of an embodiment of the present invention;

[0040] The embodiments of this invention mainly include the following component symbols:

[0041] 1. Volute body, 110. Spiral shell, 111. Spiral flow channel, 120. Buffer neck, 121. Inlet connection plate, 130. Inlet port, 131. Inlet hole, 132. Outlet connection plate, 140. Outlet port, 141. Mounting ear, 150. Flange body, 2. Sealing plate, 21. Flange opening, 22. Detailed Implementation

[0042] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to 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] Example 1

[0044] like Figures 1 to 3 As shown, a flanged volute casting includes a volute body 1 and a flange body 2. The volute body 1 includes a spiral shell 110 with a buffer neck 120, an outflow connecting plate 140, and an inflow connecting plate 130. The buffer neck 120 extends along the tangent direction of the outer circumference of the spiral shell 110. A spiral flow channel 111 is formed inside the spiral shell 110. A flow-slowing cavity 121 is formed along the inner edge of the buffer neck 120, and the flow-slowing cavity 121 extends into the spiral flow channel 111. The inflow connecting plate 130 is connected to one end of the spiral shell 110. The receiving plate 130 has an inlet 131 on its surface, which extends into the spiral flow channel 111. The spiral housing 110 has an inlet hole 132 at the other end of the inlet 131. The lower end of the flange 2 is connected to the spiral housing 110 outside the inlet hole 132. The spiral flow channel 111 communicates with the inner cavity of the flange 2 through the inlet hole 132. The outlet connecting plate 140 is connected to the end face of the buffer neck 120. The outlet connecting plate 140 has an outlet 141 on its surface, which extends into the slow flow cavity 121.

[0045] A sealing disc 21 is provided at the upper end of the flange body 2. A flange opening 22 is opened on the surface of the sealing disc 21. The flange opening 22 extends along the inner cavity of the flange body 2 to the inlet hole 132.

[0046] The outflow connecting plate 140, buffer neck 120, spiral shell 110, inflow connecting plate 130, flange body 2 and sealing plate 21 are all designed as an integrally formed structure.

[0047] The outflow connecting plate 140, the inflow connecting plate 130, and the sealing plate 21 are all integrally formed with several mounting ears 150 on their sides, which facilitates drilling threaded holes during subsequent machining.

[0048] The diameter of the inlet 131 is the maximum position diameter of the spiral channel 111.

[0049] The diameter of the inlet hole 132 is smaller than the diameter of the inlet port 131.

[0050] A manufacturing process for a flanged volute casting, the manufacturing process comprising the following steps:

[0051] S1. Making wax molds:

[0052] S1-1, Core making: Using a special core making mold, the wax core of the volute body 1 is made with water-soluble wax according to the shape and size of the spiral flow channel 111 and the slow flow cavity 121;

[0053] S1-2. Manufacturing the volute body 1 wax model: Place the above wax core in the middle of a special volute mold and fix it. Close the mold and inject wax into the volute mold through a wax injection machine. After cooling, take out the volute wax model and place it in a citric acid aqueous solution to melt the wax core to obtain the volute body 1 wax model.

[0054] S1-3. Manufacturing the wax film of flange body 2: Inject wax into the mold of flange body 2 using a wax injection machine, and remove it after cooling to obtain the wax mold of flange body 2;

[0055] S2-1, Splicing wax mold: According to the design requirements, the flange body 2 wax mold is glued to the corresponding position of the volute body 1 wax mold. After the two wax molds are connected and tightened, the gap at the connection is filled with wax to obtain the volute wax mold with flange.

[0056] S2-2, Auxiliary splicing components: The middle round gate is glued to the inlet 131 of the volute wax mold with flange, and three flange gates are glued to the surface of the inlet connecting plate 130 of the volute wax mold with flange. After the middle round gate and the three flange gates are connected and tightened, the gap at the connection is filled with wax to obtain the volute assembly.

[0057] S3. Assembly: Weld the main runner of the disc above the above-mentioned central circular gate and three flange gates. Weld the side runner and the main runner of the outlet on the side of the main runner of the disc at both ends outside the buffer neck 120. Weld the side runner and the main runner of the outlet to both ends of the buffer neck 120 below the side runner and the main runner of the outlet through two cross gate bars. After the assembly is completed, use light to inspect and repair the gaps of the assembly with wax to obtain the volute wax module.

[0058] S4. Shell making: After cleaning the volute wax model until it is free of oil and wax residue and air-drying it, the surface of the volute wax model is coated with paint and sand. The first layer is zircon mortar, and the remaining 5 layers are mullite mortar. Before the 2nd, 3rd and 4th layers are sanded, silica sol is applied and air-dried.

[0059] S5. Dewaxing and dehydration: After the air-dried volute wax mold is completely melted in a steam furnace, it is heated to 1200℃ and held for 40-50 minutes to remove excess wax and moisture, thus obtaining a sand shell.

[0060] S6. Casting: A regenerative natural gas roasting furnace is used to prepare the furnace charge. The roasting temperature is required to be 1100℃-1200℃. After the molten steel is tapped, molten steel is poured into multiple gating channels corresponding to the sand shell. The steel is poured to the riser and placed in a sand pile to cool, thus obtaining the mold shell.

[0061] S7. Finishing: Remove the sand shell outside the mold shell and shot blast, requiring 0.4mm steel shot for 15-20 minutes to obtain the volute housing casting.

[0062] S8. Removal of sprues and gates: Use a plasma cutter to cut the sprues and three flange gates of the volute assembly casting, and use a drill press to drill out the central round gate to obtain a semi-finished casting.

[0063] S9. Inspection and Repair: Use light inspection and endoscope to check for gaps and sand holes in the semi-finished castings. Repair the defective parts with argon arc welding, and then use shot blasting machine to polish the flow channels and surface to remove residual sand, dirt and oxide layer polishing marks.

[0064] S10. Final inspection and warehousing: The dimensions and appearance meet the requirements of the drawings. The parts are cleaned, packaged and put into storage to obtain the volute casting with flange.

[0065] In step S4, the required drying temperature is 20℃-25℃, the humidity gradually decreases, and the drying wind speed increases. The shell-making parameters in step S4 are as follows (see Table 1):

[0066]

[0067] Table 1

[0068] The raw materials for the molten steel in step S6 include at least 304 furnace charge, high chromium, nickel plate, ferrosilicon and metallic manganese.

[0069] Step S10 further includes: S10-1, pressure test: through air tightness test, it is required to meet the allowable leakage of 20 cm cubic meters / minute at 1.5 bar.

[0070] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A manufacturing process for a flanged volute casting, characterized in that, The flanged volute casting includes a volute body and a flange body. The volute body includes a spiral shell with a buffer neck, an outlet connecting plate, and an inlet connecting plate. The buffer neck extends along the tangent direction of the outer circle of the spiral shell. A spiral flow channel is formed inside the spiral shell. A slow-flow cavity is formed along the inner edge of the buffer neck, and the slow-flow cavity extends into the spiral flow channel. The inlet connecting plate is connected to one end of the spiral shell. An inlet port is formed on the surface of the inlet connecting plate, and the inlet port extends into the spiral flow channel. An inlet hole is formed at the other end of the spiral shell located at the inlet port. The lower end of the flange body is connected to the spiral shell located outside the inlet hole. The spiral flow channel communicates with the inner cavity of the flange body through the inlet hole. The outlet connecting plate is connected to the end face of the buffer neck. An outlet port is formed on the surface of the outlet connecting plate, and the outlet port extends into the slow-flow cavity. The manufacturing process includes the following steps: S1. Making wax molds: S1-1, Core making: Using a special core making mold, the wax core of the volute body is made with water-soluble wax according to the shape and size of the spiral flow channel and the slow flow cavity; S1-2. Manufacturing the volute body wax model: Place the wax core in the middle of a special volute mold and fix it. Close the mold and inject wax into the volute mold using a wax injection machine. After cooling, remove the volute wax model and place it in a citric acid aqueous solution to melt the wax core, thus obtaining the volute body wax model. S1-3. Manufacturing flange body wax model: Inject wax into the flange body mold using a wax injection machine, remove it after cooling to obtain the flange body wax model; S2-1, Splicing Wax Model: According to the installation design requirements, the flange wax model is glued to the corresponding position of the volute body wax model. After the two wax models are connected and tightened, the gap at the connection is filled with wax to obtain the volute wax model with flange. S2-2, Auxiliary splicing components: The middle round gate is glued to the inlet of the flanged volute wax mold, and three flange gates are glued to the surface of the inlet connecting plate of the flanged volute wax mold. After the middle round gate and the three flange gates are connected and tightened, the gaps at the connection are filled with wax to obtain the volute assembly. S3, Assembly: Weld the main runner of the disc above the above-mentioned central circular gate and three flange gates. Weld the side runner and the main runner of the outlet on the side of the main runner at both ends of the outer side of the buffer neck. Weld the side runner and the main runner of the outlet to both ends of the outer side of the buffer neck through two cross gate bars. After the assembly is completed, use light to inspect and repair the gaps of the assembly with wax to obtain the volute wax module. S4. Shell Making: After cleaning the volute wax model until it is free of oil and wax residue and air-drying it naturally, the surface of the volute wax model is coated and sanded. The first layer is zircon mortar, and the remaining five layers are mullite mortar. Before sanding, the second, third, and fourth layers are coated with silica sol. They are air-dried under different wind speeds and humidity conditions. The required temperature for each air-drying is 20℃-25℃. The air-drying humidity of the second layer is lower than that of the first layer, and the air-drying humidity of the third to sixth layers is lower than that of the second layer. The wind speed of the second layer is higher than that of the first layer, and the wind speed of the third to sixth layers is higher than that of the second layer. S5. Dewaxing and dehydration: After the air-dried volute wax mold is completely melted in a steam furnace, the excess wax and moisture are removed at high temperature to obtain a sand shell. S6. Casting: A regenerative natural gas roasting furnace is used to prepare the furnace charge. After the molten steel is produced, it is poured into multiple gating channels corresponding to the sand shell. The steel is poured to the riser and placed in a sand pile to cool, thus obtaining the mold shell. S7. Finishing: Remove the sand shell outside the mold shell and shot blast to obtain the volute-shaped tree casting; S8. Removal of sprues and gates: Use a plasma cutter to cut the sprues and three flange gates of the volute assembly casting, and use a drill press to drill out the central round gate to obtain a semi-finished casting. S9. Inspection and Repair: Inspect the gaps and sand holes in the semi-finished castings. Repair the defective positions by argon arc welding, and then continue to use shot blasting machine to polish the flow channels and surfaces to remove residual sand, dirt and oxide layer polishing marks. S10. Final inspection and warehousing: The dimensions and appearance meet the requirements of the drawings. The parts are cleaned, packaged and put into storage to obtain the volute casting with flange.

2. The manufacturing process according to claim 1, characterized in that, In step S5, the high temperature for removing excess wax and moisture should be heated to 1200°C and maintained for 40-50 minutes.

3. The manufacturing process according to claim 1, characterized in that, In step S6, the raw materials for molten steel include at least 304 furnace charge, high chromium material, nickel plate, ferrosilicon and metallic manganese, and the roasting temperature is required to be 1100℃-1200℃.

4. The manufacturing process according to claim 1, characterized in that, In step S7, shot blasting requires the use of 0.4mm steel shot for 15-20 minutes.

5. The manufacturing process according to claim 1, characterized in that, In step S9, gaps and sand holes are detected by means of light inspection and endoscopy.

6. The manufacturing process according to claim 1, characterized in that, Step S10 further includes: S10-1, pressure test: through air tightness test, it is required to meet the allowable leakage of 20 cm cubic meters / minute at 1.5 bar.

7. A flanged volute casting manufactured using the manufacturing process described in any one of claims 1-6, characterized in that, A sealing plate is provided at the upper end of the flange body, and a flange opening is opened on the surface of the sealing plate. The flange opening extends along the inner cavity of the flange body to the inlet hole. The outlet connecting plate, buffer neck, spiral shell, inlet connecting plate, flange body and sealing plate are all integrally formed structures. Several mounting ears are integrally formed on the sides of the outlet connecting plate, inlet connecting plate and sealing plate.

8. The flanged volute casting according to claim 7, characterized in that: The diameter of the inlet is the maximum diameter of the spiral channel; the diameter of the inlet hole is smaller than the diameter of the inlet.

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