A complex volute shell type investment casting of heat-resistant steel material and a production process thereof

Abstract

The present application belongs to the technical field of investment casting, and particularly relates to a complex volute shell type investment casting of heat-resistant steel material and a production process thereof, comprising the following steps: step S1, making and assembling split water-soluble wax cores according to a product to be processed; step S2, placing the assembled water-soluble wax cores in a product mold when pressing a product wax mold, and then pressing out the product wax mold; step S3, performing tree assembly after removing the water-soluble wax cores from the product wax mold, to obtain a pouring system; step S4, adopting a double-layer process to make a shell, and the shell making process comprises sand pouring, multiple times of grouting and pre-sealing grouting process; step S5, performing dewaxing on the shell, and then performing pre-baking treatment and furnace cooling; step S6, pouring of the product to be processed; and step S7, after the pouring is completed, performing vibration shell removal, to obtain a casting. The present application can greatly improve the quality of the volute shell type investment casting by combining the water-soluble wax cores and adopting a one-time forming method of the volute shell and its assembly parts through the investment casting, so that the welding process is omitted.

Description

Technical Field

[0001] This invention belongs to the field of investment casting technology, specifically relating to a complex spiral-shaped investment casting made of heat-resistant steel and its production process. Background Technology

[0002] Currently, volute-type products are difficult to manufacture using machining methods, and are usually produced through investment casting. Some heat-resistant steel volutes cannot be directly assembled and used; instead, they need to be welded together with other products to form an assembly, which is then machined to form the desired product. The welding process is prone to problems such as leakage and misalignment due to poor welding, affecting the overall quality of the casting. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a complex spiral-shaped investment casting made of heat-resistant steel and its manufacturing process. This invention eliminates the welding process by combining a water-soluble wax core and using a spiral casing and its assemblies to form the casting in one step through investment casting. This method significantly improves the quality of spiral-shaped investment castings by manufacturing complex spiral-shaped parts through investment casting.

[0004] To achieve the above technical objectives, the technical solution adopted in the embodiments of the present invention is as follows:

[0005] In a first aspect, embodiments of the present invention provide a manufacturing process for complex spiral-shaped investment castings made of heat-resistant steel, comprising the following steps:

[0006] Step S1: Assemble the water-soluble wax core: Make a water-soluble wax core according to the product to be processed. The hollow part of the inner cavity of the product to be processed adopts a split water-soluble wax core scheme. First, press out the first water-soluble wax core and the second water-soluble wax core respectively, and then assemble the first water-soluble wax core and the second water-soluble wax core together.

[0007] Step S2: Prepare product wax mold: Make product wax mold according to the product to be processed. When pressing the product wax mold, place the water-soluble wax core assembled in step S1 into the product mold, and then press out the product wax mold.

[0008] Step S3: After removing the water-soluble wax core from the product wax model obtained in step S2, the wax model is assembled into a gating system including a pouring cup, a horizontal runner, a side runner, and an ingate.

[0009] Step S4, Shell Preparation: The shell is made using a double-layer process, which includes sand filling, multiple grouting, and pre-sealing processes.

[0010] Step S5: Dewax the shell obtained in step S4 using a steam dewaxing kettle. After dewaxing, let it stand for more than 12 hours. Then, pre-baking the shell is carried out at a temperature of 850-1000℃ for more than 2 hours. After baking, the temperature is lowered with the furnace. After cooling to below 400℃, the shell is taken out.

[0011] Step S6: Casting of the product to be processed: The temperature of the mold shell is 1050±20℃ and the temperature of the molten steel is 1630-1640℃ when the product is cast.

[0012] Step S7: After casting, the outer mold shell is removed by vibration. The refractory mortar used during sand pouring will also be removed in this process, as will the zircon sand poured in. Then, the slurry poured into the inner cavity is cleaned by hydraulic sand cleaning. After hydraulic sand cleaning, the remaining mold shell is removed by dry spray sand cleaning to obtain the casting.

[0013] Furthermore, the ingates in step S3 include a first ingate, a second ingate, a third ingate, a fourth ingate, a fifth ingate, and a sixth ingate.

[0014] Furthermore, the sprue cup is arranged perpendicularly to the horizontal runner, and the side runner includes a first side runner, a second side runner, a third side runner, a fourth side runner, and a fifth side runner. The inlet ends of the first side runner, the second side runner, the fourth side runner, and the fifth side runner are all connected to the horizontal runner. The outlet end of the first side runner is connected to the product wax model through the fifth inner gate. The outlet end of the second side runner is connected to the product wax model through the first inner gate. The third side runner is connected to the product wax model through the second inner gate. The fourth side runner is connected to the product wax model through the third inner gate. The fifth side runner is connected to the product wax model through the fourth inner gate. The horizontal runner is connected to the product wax model through the sixth inner gate.

[0015] The outlet end of the fourth side gating is connected to the third side gating.

[0016] Furthermore, the cross-section of the first ingate is an isosceles trapezoid with an oblique angle of 15-25° and a height of 35±2mm. The inner and outer sides of the first ingate are designed as arcs along the edge of the casting, with an arc length of 35-50mm, and there are a total of 3 arcs.

[0017] The second inner gate is frustum-shaped, with a diameter of 11-15mm for the plane connecting to the product wax mold, a diameter of 20-26mm for the plane connecting to the third side gate, and a height of 25-35mm, for a total of 1 gate;

[0018] The cross-section of the third ingate is an isosceles trapezoid with an oblique angle of 15-25°, a height of 35-45mm, and a length of 30-35mm, and there are a total of 4 ingates;

[0019] The fourth inner gate is frustum-shaped, with a diameter of 8-11mm for the plane connecting to the product wax mold, a diameter of 14-18mm for the plane connecting to the fifth side gate, and a height of 20-30mm, for a total of 8 gates;

[0020] The fifth ingate has an isosceles trapezoidal cross-section with an oblique angle of 15-25°, a height of 35-45mm, and a length of 25-35mm, and there is one in total;

[0021] The sixth ingate is a contour ingate, shaped like the number "8". The diameter of the two circles at the connection with the product wax mold is 6-8mm, and the diameter of the two circles at the connection with the horizontal runner is 10-12mm.

[0022] Furthermore, in step S4, the outer and second layers are made of 80-120 mesh zircon sand, and the drying time is 10-14 hours.

[0023] The third and fourth layers are made of 60-80 mesh mullite, and the drying time is 16-20 hours.

[0024] After the four layers are completed, pre-sealing grout is applied and the mixture is dried for 20-24 hours.

[0025] The five layers are made of 30-60 mesh mulley sand, and the drying time is 20-24 hours.

[0026] Furthermore, during the grouting process in step S4, the flow channel portion of the volute is grouted in four stages. During the first grouting, the volute's pouring cup is placed downwards, and grouting is performed from the pouring port of the fourth side pouring channel, filling the portion below the pouring port of the fourth side pouring channel with grout.

[0027] Six to eight hours after the first grouting is completed, rotate the module 90° counterclockwise and grout the second area.

[0028] Six to eight hours after the second grouting is completed, rotate the module counterclockwise by 90° and grout the third area.

[0029] Six to eight hours after the third grouting is completed, rotate the module counterclockwise by 90°. Allow the grouting to dry for at least eight hours after the third grouting.

[0030] Inspect the grouting area, and perform a fourth grouting for any areas that have not been properly grouted. After drying for more than 12 hours, begin the sand filling operation.

[0031] Furthermore, during the sand filling process in step S4, the three holes—the second, third, and fourth—are first sealed with refractory clay, and then 80-120 mesh zircon sand is poured into the cavity through the first hole.

[0032] Furthermore, after sand filling and grouting are completed in step S4, the mold shell is dried for more than 48 hours before the sixth shell is made. 16-30 mesh mullite is used for the sixth to eighth layers, and the drying time is 12-16 hours. After the eighth shell is made, the grout is applied. When grouting, only the grout is applied and no sand is poured.

[0033] Furthermore, during step S6, refractory bricks with a thickness of 40-60mm are used to support the mold shell to prevent the product from directly contacting the sand tray.

[0034] Secondly, embodiments of the present invention provide a complex spiral-shaped investment casting made of heat-resistant steel, which is produced using the production process described in the first aspect. By mass fraction, it comprises the following components: carbon 0.25%-0.35%, silicon ≤1.75%, manganese ≤1.5%, phosphorus ≤0.04%, sulfur ≤0.04%, chromium 23%-27%, nickel 19%-22%, molybdenum ≤0.5%, with the balance being iron.

[0035] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows:

[0036] 1. This invention combines water-soluble wax cores and uses a volute and its components to form a single piece through investment casting, eliminating the welding process, reducing product production costs, and preventing a series of problems such as leakage and positional misalignment caused by poor welding, thus greatly improving the quality of volute-type investment castings.

[0037] 2. This invention employs a multi-stage grouting method, followed by pre-sealing and sand-filling processes to complete the shell-making process. Existing technologies mostly use integral ceramic cores, which have complex structures, high costs, and require core removal. While the shell-making method of this invention is relatively complex, it is low-cost and easy to clean.

[0038] 3. Ceramic cores were not used in cases of extremely complex cavities, reducing production costs. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of the first water-soluble wax core in an embodiment of the present invention.

[0040] Figure 2 This is a schematic diagram of the structure of the second water-soluble wax core in an embodiment of the present invention.

[0041] Figure 3 This is a schematic diagram of the structure of the first and second water-soluble wax cores assembled together.

[0042] Figure 4 This is a schematic diagram of the product wax mold in an embodiment of the present invention.

[0043] Figure 5 This is a front view of the casting system in an embodiment of the present invention.

[0044] Figure 6 This is a left view of the casting system in an embodiment of the present invention.

[0045] Figure 7 This is a schematic diagram of the placement of the mold shell during grouting in an embodiment of the present invention.

[0046] Figure 8 This is a schematic diagram of the structure of the area to be filled by grouting in an embodiment of the present invention.

[0047] Figure 9 This is a schematic diagram of the structure of the sealing hole and the sand filling hole during sand filling in an embodiment of the present invention.

[0048] Figure 10 This is a schematic diagram showing the placement of refractory bricks during casting in an embodiment of the present invention.

[0049] Explanation of reference numerals in the attached diagram: 1-First water-soluble wax core; 2-Second water-soluble wax core; 3-Pour cup; 4-Horizontal runner; 5-Side runner; 6-Ingate; 7-Second region; 8-Third region; 9-First region; 10-Second hole; 11-Third hole; 12-Fourth hole; 13-First hole; 14-Refractory brick; 51-First side runner; 52-Second side runner; 53-Third side runner; 54-Fourth side runner; 55-Fifth side runner; 61-First ingate; 62-Second ingate; 63-Third ingate; 64-Fourth ingate; 65-Fifth ingate; 66-Sixth ingate. Detailed Implementation

[0050] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "inner" and "outer", "upper" and "lower", "left" and "right" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this invention.

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0052] Example 1

[0053] A manufacturing process for complex spiral-shaped investment castings made of heat-resistant steel includes the following steps:

[0054] Step S1: Assemble the water-soluble wax core: Prepare the water-soluble wax core according to the product to be processed. The hollow inner cavity of the product to be processed adopts a split water-soluble wax core scheme. First, press out the first water-soluble wax core 1 and the second water-soluble wax core 2 separately, as follows: Figure 1 and 2 As shown, the first water-soluble wax core 1 and the second water-soluble wax core 2 are then assembled, as follows. Figure 3 As shown;

[0055] Step S2, Preparing the Product Wax Model: A product wax model is made according to the product to be processed. When pressing the product wax model, the water-soluble wax core assembled in step S1 is placed in the product mold, and then the product wax model is pressed out, as shown below. Figure 4 As shown;

[0056] Step S3: After removing the water-soluble wax core from the product wax model obtained in step S2, assemble the mold. The resulting gating system includes a pouring cup 3, a horizontal runner 4, a side runner 5, and an inner gate 6, as shown below. Figure 5 and 6 As shown, the cross-sectional area of ​​the horizontal sprue is 40 mm × 50 mm;

[0057] The inner gate 6 includes a first inner gate 61, a second inner gate 62, a third inner gate 63, a fourth inner gate 64, a fifth inner gate 65, and a sixth inner gate 66.

[0058] The cross-section of the first ingate 61 is an isosceles trapezoid with an oblique angle of 15-25° and a height of 35mm±2. The inner and outer sides of the first ingate 61 are designed as arcs along the edge of the casting with an arc length of 35-50mm, and there are a total of 3 ingates.

[0059] The second inner gate 62 is frustum-shaped, with a diameter of 11-15mm for the plane connecting to the product wax model, a diameter of 20-26mm for the plane connecting to the third side gate 53, and a height of 25-35mm. There is one such gate.

[0060] The cross-section of the third ingate 63 is an isosceles trapezoid with an oblique angle of 15-25°, a height of 35-45mm, and a length of 30-35mm. There are a total of 4 ingates.

[0061] The fourth inner gate 64 is frustum-shaped, with a diameter of 8-11mm for the plane connecting to the product wax model, a diameter of 14-18mm for the plane connecting to the fifth side gate 55, and a height of 20-30mm, for a total of 8 gates;

[0062] The fifth ingate 65 has an isosceles trapezoidal cross-section with an oblique angle of 15-25°, a height of 35-45mm, and a length of 25-35mm. There is one in total.

[0063] The sixth ingate 66 is a contour ingate, shaped like the number "8". The diameter of the two circles at the connection with the product wax model is 6-8mm, and the diameter of the two circles at the connection with the horizontal runner 4 is 10-12mm.

[0064] The pouring cup 3 is set perpendicularly to the horizontal runner 4. The side runner 5 includes a first side runner 51, a second side runner 52, a third side runner 53, a fourth side runner 54, and a fifth side runner 55. The inlet ends of the first side runner 51, the second side runner 52, the fourth side runner 54, and the fifth side runner 55 are all connected to the horizontal runner 4. The cross-sectional area of ​​the first side runner 51, the second side runner 52, the fourth side runner 54, and the fifth side runner 55 is 40 mm × 40 mm.

[0065] The outlet end of the first side runner 51 is connected to the product wax model through the fifth inner gate 65; the outlet end of the second side runner 52 is connected to the product wax model through the first inner gate 61; the third side runner 53 is connected to the product wax model through the second inner gate 62; the fourth side runner 54 is connected to the product wax model through the third inner gate 63; the fifth side runner 55 is connected to the product wax model through the fourth inner gate 64; and the horizontal runner 4 is connected to the product wax model through the sixth inner gate 66.

[0066] The outlet end of the fourth side runner 54 is connected to the third side runner 53.

[0067] Step S4, Shell Preparation: The shell is made using a double-layer process, which includes sand filling, multiple grouting, and pre-sealing processes.

[0068] The outer and second layers of the shell are made of 80-120 mesh zircon sand, and the drying time is 10-14 hours.

[0069] The third and fourth layers use 60-80 mesh mullite sand, and the drying time is 16-20 hours;

[0070] After the four layers are completed, pre-sealing grouting is performed and the grout is dried for 20-24 hours;

[0071] The fifth layer uses 30-60 mesh mulley sand, and the drying time is 20-24 hours.

[0072] During grouting, the flow channel of the volute is grouted in four stages. For the first grouting, the volute's pouring cup 3 is placed face down, and grout is poured from the gating orifice of the fourth side gating 54. A plastic bottle with a spout is used to fill the portion below the gating orifice of the fourth side gating 54 with grout. Figure 7 and 8 As shown;

[0073] Six to eight hours after the first grouting is completed, rotate the module 90° counterclockwise and grout the second area 7.

[0074] Six to eight hours after the second grouting is completed, rotate the module counterclockwise by 90° and grout the third area 8.

[0075] Six to eight hours after the third grouting is completed, rotate the module counterclockwise by 90°. Allow the grouting to dry for at least eight hours after the third grouting.

[0076] Inspect the grouting area, and perform a fourth grouting for any areas that have not been properly grouted. After drying for more than 12 hours, begin the sand filling operation.

[0077] During sand filling, first seal the three holes (2nd hole 10, 3rd hole 11, and 4th hole 12) with refractory clay. Then, pour 80-120 mesh zircon sand into the cavity through the first hole 13. Figure 9 As shown;

[0078] Pay special attention to the red area of ​​the first hole 13. This area is connected to the previous grouting area. When grouting sand to this position, it needs to be shaken repeatedly 3-5 times to ensure that all the sand enters the area. After the inner cavity is completely filled, seal this hole with refractory mortar.

[0079] After sand filling and grouting are completed, the mold shell is dried for more than 48 hours before the 6th shell is made. 16-30 mesh mullite is used for the 6th to 8th layers, and the drying time is 12-16 hours. After the 8th shell is made, the grout is applied. When grouting, only the grout is applied and no sand is poured.

[0080] Step S5: Dewax the shell obtained in step S4 using a steam dewaxing kettle. After dewaxing, let it stand for more than 12 hours. Then, pre-baking the shell is carried out at a temperature of 850-1000℃ for more than 2 hours. After baking, the temperature is lowered with the furnace. After cooling to below 400℃, the shell is taken out.

[0081] Step S6: Casting of the product to be processed: The temperature of the mold shell is 1050±20℃ and the temperature of the molten steel is 1630-1640℃ when the product is cast.

[0082] During casting, use refractory bricks (14) with a cross-sectional area of ​​50mm × 80mm and a thickness of 40-60mm to support the mold shell, preventing the product from directly contacting the sand tray. Figure 10 As shown;

[0083] Step S7: After casting, the outer mold shell is removed by vibration. The refractory mortar used during sand pouring will also be removed in this process, as will the zircon sand poured in. Then, the slurry poured into the inner cavity is cleaned by hydraulic sand cleaning. After hydraulic sand cleaning, the remaining mold shell is removed by dry spray sand cleaning to obtain the casting.

[0084] A complex spiral-shaped investment casting made of heat-resistant steel is produced using the above-mentioned manufacturing process. The material is HK30ASTM A351, and by mass fraction, it includes the following components: carbon 0.25%-0.35%, silicon ≤1.75%, manganese ≤1.5%, phosphorus ≤0.04%, sulfur ≤0.04%, chromium 23%-27%, nickel 19%-22%, molybdenum ≤0.5%, and the balance is iron.

[0085] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A manufacturing process for complex spiral-shaped investment castings made of heat-resistant steel, characterized in that, Includes the following steps: Step S1: Assemble the water-soluble wax core: Make a water-soluble wax core according to the product to be processed. The hollow part of the inner cavity of the product to be processed adopts a split water-soluble wax core scheme. First, press out the first water-soluble wax core (1) and the second water-soluble wax core (2) respectively, and then assemble the first water-soluble wax core (1) and the second water-soluble wax core (2). Step S2: Prepare product wax mold: Make product wax mold according to the product to be processed. When pressing the product wax mold, place the water-soluble wax core assembled in step S1 into the product mold, and then press out the product wax mold. Step S3: After removing the water-soluble wax core from the product wax model obtained in step S2, the wax model is assembled into a gating system including a gating cup (3), a horizontal runner (4), a side runner (5), and an inner gate (6). Step S4, Shell Preparation: The shell is made using a double-layer process, which includes sand filling, multiple grouting, and pre-sealing processes. Step S5: Dewax the shell obtained in step S4 using a steam dewaxing kettle. After dewaxing, let it stand for more than 12 hours. Then, pre-baking the shell is carried out at a temperature of 850-1000℃ for more than 2 hours. After baking, the temperature is lowered with the furnace. After cooling to below 400℃, the shell is taken out. Step S6: Casting of the product to be processed: The temperature of the mold shell is 1050±20℃ and the temperature of the molten steel is 1630-1640℃ when the product is cast. Step S7: After casting, the outer mold shell is removed by vibration. The refractory mortar used during sand pouring is also removed in this process, as is the zircon sand poured in. Then, the slurry poured into the inner cavity is cleaned by hydraulic sand cleaning. After hydraulic sand cleaning, the remaining mold shell is removed by dry sand spraying to obtain the casting. The ingate (6) in step S3 includes a first ingate (61), a second ingate (62), a third ingate (63), a fourth ingate (64), a fifth ingate (65), and a sixth ingate (66). The pouring cup (3) is perpendicular to the runner (4). The side runner (5) includes a first side runner (51), a second side runner (52), a third side runner (53), a fourth side runner (54), and a fifth side runner (55). The inlet ends of the first side runner (51), the second side runner (52), the fourth side runner (54), and the fifth side runner (55) are all connected to the runner (4). The outlet end of the first side runner (51) is through the fifth ingate. (65) is connected to the product wax model. The outlet end of the second side runner (52) is connected to the product wax model through the first inner gate (61). The third side runner (53) is connected to the product wax model through the second inner gate (62). The fourth side runner (54) is connected to the product wax model through the third inner gate (63). The fifth side runner (55) is connected to the product wax model through the fourth inner gate (64). The horizontal runner (4) is connected to the product wax model through the sixth inner gate (66). The outlet end of the fourth side gating (54) is connected to the third side gating (53); The first ingate (61) has an isosceles trapezoidal cross section with an oblique angle of 15-25° and a height of 35±2mm. The inner and outer sides of the first ingate (61) are designed as arcs along the edge of the casting with an arc length of 35-50mm, and there are a total of 3 ingates. The second inner gate (62) is frustum-shaped, with a plane diameter of 11-15mm connected to the product wax mold, a plane diameter of 20-26mm connected to the third side gate (53), and a height of 25-35mm, for a total of 1; The cross-section of the third ingate (63) is an isosceles trapezoid with an oblique angle of 15-25°, a height of 35-45mm, and a length of 30-35mm, and there are a total of 4 ingates; The fourth inner gate (64) is frustum-shaped, with a plane diameter of 8-11mm connected to the product wax mold, a plane diameter of 14-18mm connected to the fifth side gate (55), and a height of 20-30mm, for a total of 8 gates; The fifth ingate (65) has an isosceles trapezoidal cross section with an oblique angle of 15-25°, a height of 35-45mm, and a length of 25-35mm, and there is one in total; The sixth ingate (66) is a contour ingate, shaped like the number "8". The diameter of the two circles at the connection with the product wax mold is 6-8mm, and the diameter of the two circles at the connection with the horizontal runner (4) is 10-12mm.

2. The production process of complex spiral-shaped investment castings made of heat-resistant steel according to claim 1, characterized in that, In step S4, the surface layer and the second layer are made of 80-120 mesh zircon sand, and the drying time is 10-14 hours. The third and fourth layers use 60-80 mesh mullite sand, and the drying time is 16-20 hours; After the four layers are completed, pre-sealing grouting is performed and the mixture is dried for 20-24 hours; The fifth layer uses 30-60 mesh mulley sand, and the drying time is 20-24 hours.

3. The production process of complex spiral-shaped investment castings made of heat-resistant steel according to claim 1, characterized in that, In step S4, the flow channel of the volute is grouted in four times. During the first grouting, the volute's pouring cup (3) is placed downwards, and grout is poured from the pouring port of the fourth side pouring channel (54) to fill the part below the pouring port of the fourth side pouring channel (54) with grout. Six to eight hours after the first grouting is completed, rotate the module counterclockwise by 90° and grout the second area (7); Six to eight hours after the second grouting is completed, rotate the module counterclockwise by 90° and grout the third area (8); Six to eight hours after the third grouting is completed, rotate the module counterclockwise by 90°. Allow the grouting to dry for at least eight hours after the third grouting. Inspect the grouting area, and perform a fourth grouting for any areas that have not been properly grouted. After drying for more than 12 hours, begin the sand filling operation.

4. The production process of complex spiral-shaped investment castings made of heat-resistant steel material according to claim 1 or 3, characterized in that, In step S4, when filling the cavity with sand, first seal the three holes (10), (11), and (12) with refractory mud, and then fill the cavity with 80-120 mesh zircon sand from the first hole (13).

5. The production process of complex spiral-shaped investment castings made of heat-resistant steel according to claim 1, characterized in that, After sand filling and grouting are completed in step S4, the mold shell is dried for more than 48 hours before the 6th shell is made. 16-30 mesh mullite is used for the 6th to 8th layers, and the drying time is 12-16 hours. After the 8th shell is made, the grout is applied. When grouting, only the grout is applied and no sand is poured.

6. The production process of complex spiral-shaped investment castings made of heat-resistant steel according to claim 1, characterized in that, During step S6, refractory bricks with a thickness of 40-60mm are used to support the mold shell to prevent the product from directly contacting the sand tray.

7. A complex spiral-shaped investment casting made of heat-resistant steel, characterized in that, The product is prepared by any one of the production processes described in claims 1-6 and comprises, by mass fraction, the following components: carbon 0.25%-0.35%, silicon ≤1.75%, manganese ≤1.5%, phosphorus ≤0.04%, sulfur ≤0.04%, chromium 23%-27%, nickel 19%-22%, molybdenum ≤0.5%, with the balance being iron.

Images