Large reaction sintered silicon carbide ceramic closed impeller and manufacturing method thereof

Abstract

The application discloses a large-sized reaction-sintered silicon carbide ceramic closed impeller and a manufacturing method thereof. The impeller comprises a metal framework, a front cover plate ceramic piece, a rear cover plate ceramic piece and a ceramic blade assembly. The ceramic blade assembly is composed of a plurality of identical sector plate sub-pieces. Each sector plate sub-piece of the ceramic blade assembly is inserted into the metal framework and fixed to form a round plate-shaped blade assembly. The front cover plate ceramic piece and the rear cover plate ceramic piece are bonded to the front and rear sides of the metal framework. The manufacturing method comprises the following steps: manufacturing the front cover plate ceramic piece, the rear cover plate ceramic piece and each sector plate sub-piece of the ceramic blade assembly through a reaction sintering process; processing the metal framework; and bonding the front cover plate ceramic piece, the rear cover plate ceramic piece and the ceramic blade assembly to the metal framework and then performing solidification forming to obtain a closed impeller product. The closed impeller solves the problem of integral sintering of a large-sized impeller.

Description

Technical Field

[0001] This invention relates to a large reaction-sintered silicon carbide ceramic closed impeller and its manufacturing method, specifically to a large reaction-sintered silicon carbide ceramic impeller using a segmented sintering and splicing molding process combined with metal skeleton reinforcement, belonging to the technical field of silicon carbide ceramic impellers. Background Technology

[0002] Reaction-bonded silicon carbide ceramics possess excellent properties such as high strength, high hardness, wear resistance, corrosion resistance, and high temperature resistance, making them widely used in fluid transport equipment in chemical, metallurgical, and energy fields. However, due to the inherent brittleness of the ceramic material and limitations in the sintering process, the integral sintering and forming of silicon carbide ceramic impellers with a diameter greater than 1 meter faces two major challenges:

[0003] 1. During integral sintering, the large size of the blank leads to uneven heating, which easily causes defects such as cracking and deformation, resulting in an extremely low yield.

[0004] 2. The overall structural strength of large ceramic impellers is insufficient. Under high-speed rotation conditions, the connection between the blades and the cover plate is prone to breakage due to stress concentration, which cannot meet the long-term stable operation requirements of industrial equipment.

[0005] In existing technologies, small ceramic impellers are mostly produced using a monolithic sintering process, which cannot be directly applied to large impellers. Some spliced ​​impellers lack effective reinforcement structures, or the metal reinforcements are in direct contact with corrosive media, resulting in short impeller lifespan and poor reliability. Therefore, there is an urgent need for a structure and molding method for large reaction-sintered silicon carbide ceramic impellers that can solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to solve the problems of large-diameter closed silicon carbide ceramic impellers, which are prone to cracking and deformation during molding, resulting in low yield and insufficient overall strength. Under high-speed rotation conditions, the connection between the blade and the cover plate is prone to breakage due to stress concentration. The invention provides a large reaction-sintered silicon carbide ceramic impeller with segmented sintering and splicing and metal skeleton reinforcement, which improves the molding success rate and structural reliability while ensuring the impeller's corrosion resistance and wear resistance.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] In a first aspect, the present invention provides a large reaction-sintered silicon carbide ceramic closed impeller, comprising a metal frame, a front cover plate ceramic component, a rear cover plate ceramic component, and a ceramic blade assembly.

[0009] The metal frame includes a front support ring plate and a rear support plate arranged in parallel, a hub fixed to the rear end face of the rear support plate, and a set of stiffeners arranged circumferentially between the front support ring plate and the rear support plate.

[0010] The circumferential distribution position and extension direction of the stiffener plate are matched with the circumferential distribution position and extension direction of each blade in the finished closed impeller.

[0011] The rear end face of the ceramic part of the front cover plate is machined with a positioning groove that matches the shape of the front support ring plate of the metal frame, and the front end face of the ceramic part of the rear cover plate is machined with a positioning groove that matches the shape of the rear support plate of the metal frame. The center of the ceramic part of the rear cover plate has a hub passage hole.

[0012] The ceramic blade assembly is composed of a set of identical sector-shaped plate components radially cut from a circular plate blade assembly. The number of sector-shaped plate components corresponds to the number of metal skeleton stiffeners. The mating surfaces of two adjacent sector-shaped plate components are symmetrically provided with stiffener positioning grooves.

[0013] Each sector-shaped plate component of the ceramic blade assembly is inserted between the front support ring plate and the rear support plate of the metal frame and bonded together, such that two adjacent sector-shaped components respectively wrap around each stiffening plate; the front cover plate ceramic component is bonded to the front side of the front support ring plate of the metal frame, and the rear cover plate ceramic component is bonded to the rear side of the rear support plate of the metal frame.

[0014] Furthermore, the stiffener has circumferentially distributed adhesive holes, and the mating surfaces of the fan-shaped components are provided with corresponding adhesive pins. When the various fan-shaped components are assembled into a complete assembly, the adhesive pins are inserted into the adhesive holes to improve the radial bonding force between the ceramic blade assembly and the metal frame.

[0015] Furthermore, the front cover ceramic component and the front support ring plate are provided with circumferentially distributed front positioning pin holes. When the front cover ceramic component is bonded to the front support ring plate, ceramic positioning pins are inserted and bonded in each front positioning pin hole to improve the rotational bonding force between the front cover ceramic component and the metal frame.

[0016] Furthermore, the ceramic part of the rear cover plate is provided with circumferentially distributed rear positioning pin holes corresponding to the rear support plate. When the ceramic part of the rear cover plate is bonded to the rear support plate, ceramic positioning pins are inserted and bonded in each rear positioning pin hole to improve the rotational bonding force between the ceramic part of the rear cover plate and the metal skeleton.

[0017] Furthermore, the ceramic blade assembly has an annular positioning platform at its center on the front end face, and the front cover ceramic part has a positioning hole at its center that matches the annular positioning platform. When the front cover ceramic part is bonded to the front side of the front support ring plate, the positioning hole at the center of the front cover ceramic part is sleeved with the annular positioning platform on the front end face of the ceramic blade assembly, so that the front cover ceramic part is axially aligned with the ceramic blade assembly and the various components of the ceramic blade assembly are radially limited.

[0018] Secondly, the present invention provides a method for manufacturing a large reaction-sintered silicon carbide ceramic closed impeller, the specific steps of which are as follows:

[0019] 1) The front cover plate ceramic part, the rear cover plate ceramic part, and each sector plate component of the ceramic blade assembly are manufactured by reaction sintering process;

[0020] 2) Process the metal skeleton;

[0021] 3) Insert each sector plate component of the ceramic blade assembly between the front support ring plate and the rear support plate of the metal frame and glue them together to form an assembly, and make two adjacent sector plates wrap around the stiffener plate respectively.

[0022] 4) Attach the ceramic part of the front cover plate to the front side of the front support ring plate of the metal frame, and attach the ceramic part of the rear cover plate to the rear side of the rear support plate of the metal frame.

[0023] 5) The bonded impeller is cured and molded to obtain the finished closed impeller.

[0024] Furthermore, the curing conditions in step 5) are: curing at 150℃~160℃ for 2~3 hours.

[0025] Furthermore, each sector plate component of the front cover ceramic component, the rear cover ceramic component, and the ceramic blade assembly is formed by mixing silicon carbide powder and phenolic resin at a mass ratio of 9:1 and then sintering at 1350℃ for 3 hours.

[0026] Furthermore, the metal frame is made of 316L stainless steel.

[0027] Beneficial effects

[0028] The closed impeller manufacturing method of the present invention solves the problem of overall sintering of large impellers. By using a segmented sintering design where the number of blades corresponds to the number of segments, the large-size impeller is divided into multiple small ceramic units for individual sintering, which greatly reduces the risk of deformation and cracking during the sintering process and increases the yield from less than 30% in the prior art to more than 85%.

[0029] The closed impeller of this invention has significantly improved structural strength. The internal metal skeleton acts precisely on the stress concentration area of ​​the impeller, effectively dispersing the torque and impact load during high-speed rotation. The torsional strength of the impeller is increased by more than 40%, which can meet the long-term operating requirements of diameters below 2.5m and speeds of 1500rpm.

[0030] The closed impeller of this invention combines corrosion resistance and reliability. The metal frame is completely wrapped by ceramic components to avoid contact with corrosive media. At the same time, the splicing structure ensures that the overall corrosion resistance and wear resistance of the impeller are consistent with those of the integral ceramic impeller, extending its service life by 2-3 times.

[0031] The closed impeller manufacturing method of the present invention has high process flexibility. The segmented sintering and splicing molding process can flexibly adjust the segment size according to the impeller diameter and the number of blades, making it suitable for large fluid equipment of different specifications and highly versatile. Attached Figure Description

[0032] Figure 1 This is an exploded view of the overall structure of the closed impeller of the present invention;

[0033] Figure 2 This is a cross-sectional schematic diagram of the closed impeller of the present invention;

[0034] Figure 3 This is a half-sectional isometric view of the closed impeller of the present invention;

[0035] In the diagram, 1-front cover ceramic component, 2-ceramic blade assembly, 3-metal frame, 4-rear cover ceramic component. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0037] Example 1:

[0038] Taking the machining of a large reaction-sintered silicon carbide ceramic closed impeller with a diameter of 1.2m and 5 blades as an example, the closed impeller is as follows: Figure 1-3 As shown, it includes a metal frame 3, a front cover ceramic component 1, a rear cover ceramic component 4, and a ceramic blade assembly;

[0039] The metal frame 3 includes a front support ring plate and a rear support plate arranged in parallel, a hub fixed to the rear end face of the rear support plate, and a set of stiffeners arranged circumferentially between the front support ring plate and the rear support plate.

[0040] The circumferential distribution position and extension direction of the stiffener plate are matched with the circumferential distribution position and extension direction of each blade in the finished closed impeller.

[0041] The rear end face of the front cover ceramic part 1 is machined with a positioning groove that matches the shape of the front support ring plate of the metal frame 3, and the front end face of the rear cover ceramic part 4 is machined with a positioning groove that matches the shape of the rear support plate of the metal frame 3. The center of the rear cover ceramic part 4 has a hub passage hole.

[0042] The ceramic blade assembly is composed of a set of identical sector-shaped plate components radially cut from a circular plate blade assembly. The number of sector-shaped plate components corresponds to the number of the metal skeleton 3 stiffeners. The mating surfaces of two adjacent sector-shaped plate components are symmetrically provided with stiffener positioning grooves.

[0043] Each fan-shaped plate component of the ceramic blade assembly is inserted between the front support ring plate and the rear support plate of the metal frame 3 and bonded together, such that two adjacent fan-shaped components respectively wrap around each stiffening plate; the front cover plate ceramic component 1 is bonded to the front side of the front support ring plate of the metal frame 3, and the rear cover plate ceramic component 4 is bonded to the rear side of the rear support plate of the metal frame 3.

[0044] The stiffener has evenly distributed circumferential bonding holes, and the mating surfaces of the fan-shaped components are provided with corresponding bonding pins. When the various fan-shaped components are assembled into a whole, the bonding pins are inserted into the bonding holes to improve the radial bonding force between the ceramic blade assembly and the metal frame 3.

[0045] The front cover ceramic part 1 and the front support ring plate are provided with circumferentially distributed front positioning pin holes. When the front cover ceramic part 1 and the front support ring plate are bonded together, ceramic positioning pins are inserted and bonded into each front positioning pin hole to improve the rotational bonding force between the front cover ceramic part 1 and the metal skeleton 3.

[0046] The rear cover ceramic part 4 and the rear support plate are provided with circumferentially distributed rear positioning pin holes. When the rear cover ceramic part 4 is bonded to the rear support plate, ceramic positioning pins are inserted and bonded in each rear positioning pin hole to improve the rotational bonding force between the rear cover ceramic part 4 and the metal skeleton 3.

[0047] The ceramic blade assembly has an annular positioning platform at the center of its front end face, and the front cover ceramic part 1 has a positioning hole at its center that matches the annular positioning platform. When the front cover ceramic part 1 is bonded to the front side of the front support ring plate, the positioning hole at the center of the front cover ceramic part 1 is sleeved with the annular positioning platform at the front end face of the ceramic blade assembly, so that the front cover ceramic part 1 is axially aligned with the ceramic blade assembly and the various components of the ceramic blade assembly are radially limited.

[0048] Example 2:

[0049] A method for fabricating a large reaction-sintered silicon carbide ceramic closed impeller, the specific steps of which are as follows:

[0050] 1) The front cover plate ceramic part 1, the rear cover plate ceramic part 4, and each sector plate component of the ceramic blade assembly are respectively manufactured by reaction sintering process; the front cover plate ceramic part 1, the rear cover plate ceramic part 4, and each sector plate component of the ceramic blade assembly are all made by mixing silicon carbide powder and phenolic resin at a mass ratio of 9:1 and sintering at 1350℃ for 3h.

[0051] 2) The metal frame 3 is machined using 316L stainless steel;

[0052] 3) Insert each sector plate component of the ceramic blade assembly between the front support ring plate and the rear support plate of the metal frame 3 and glue them together to form an assembly, and make two adjacent sector plates wrap around the stiffener plate respectively.

[0053] 4) Attach the front cover ceramic part 1 to the front side of the front support ring plate of the metal frame 3, and attach the rear cover ceramic part 4 to the rear side of the rear support plate of the metal frame 3.

[0054] 5) Cure the bonded impeller at 160℃ for 3 hours to obtain the closed impeller finished product.

Claims

1. A large reaction-sintered silicon carbide ceramic closed impeller, characterized in that, It includes a metal frame (3), a front cover ceramic component (1), a rear cover ceramic component (4), and a ceramic blade assembly (3). The metal frame (3) includes a front support ring plate and a rear support plate arranged in parallel, a hub fixed to the rear end face of the rear support plate, and a set of stiffeners arranged circumferentially between the front support ring plate and the rear support plate. The circumferential distribution position and extension direction of the stiffener plate are matched with the circumferential distribution position and extension direction of each blade in the finished closed impeller. The rear end face of the front cover ceramic part (1) is machined with a positioning groove that matches the shape of the front support ring plate of the metal frame (3), the front end face of the rear cover ceramic part (4) is machined with a positioning groove that matches the shape of the rear support plate of the metal frame (3), and the center of the rear cover ceramic part (4) has a hub through hole. The ceramic blade assembly (3) is composed of a set of identical fan-shaped plate components that are radially cut from a circular plate blade assembly. The number of the fan-shaped plate components corresponds to the number of the stiffeners of the metal skeleton (3). The mating surfaces of two adjacent fan-shaped components are symmetrically provided with stiffener slots. Each fan-shaped plate component of the ceramic blade assembly (3) is inserted between the front support ring plate and the rear support plate of the metal frame (3) and bonded together, so that each adjacent fan-shaped component wraps around a rib plate; the front cover plate ceramic component (1) is bonded to the front side of the front support ring plate of the metal frame (3), and the rear cover plate ceramic component (4) is bonded to the rear side of the rear support plate of the metal frame (3).

2. The large reaction-sintered silicon carbide ceramic closed impeller as described in claim 1, characterized in that, The stiffener has circumferentially distributed adhesive holes, and the mating surfaces of the fan-shaped components are provided with corresponding adhesive pins. When the various fan-shaped components are assembled into a whole, the adhesive pins are inserted into the adhesive holes to improve the radial bonding force between the ceramic blade assembly (3) and the metal skeleton (3).

3. A large reaction-sintered silicon carbide ceramic closed impeller as described in claim 1, characterized in that, The front cover ceramic part (1) is provided with circumferentially distributed front positioning pin holes corresponding to the front support ring plate. When the front cover ceramic part (1) is bonded to the front support ring plate, ceramic positioning pins are inserted and bonded in each front positioning pin hole to improve the rotational bonding force between the front cover ceramic part (1) and the metal skeleton (3).

4. A large reaction-sintered silicon carbide ceramic closed impeller as described in claim 1, characterized in that, The ceramic part (4) of the rear cover plate is provided with circumferentially distributed rear positioning pin holes corresponding to the rear support plate. When the ceramic part (4) of the rear cover plate is bonded to the rear support plate, ceramic positioning pins are inserted and bonded in each rear positioning pin hole to improve the rotational bonding force between the ceramic part (4) of the rear cover plate and the metal skeleton (3).

5. A large reaction-sintered silicon carbide ceramic closed impeller as described in claim 1, characterized in that, The ceramic blade assembly (3) has an annular positioning platform at the center of its front end face, and the front cover ceramic part (1) has a positioning hole at its center that matches the annular positioning platform. When the front cover ceramic part (1) is bonded to the front side of the front support ring plate, the positioning hole at the center of the front cover ceramic part (1) is sleeved with the annular positioning platform at the front end face of the ceramic blade assembly (3), so that the front cover ceramic part (1) and the ceramic blade assembly (3) are axially aligned, and the various components of the ceramic blade assembly (3) are radially limited.

6. A method for manufacturing a large reaction-sintered silicon carbide ceramic closed impeller, the method being applied to the manufacture of a large reaction-sintered silicon carbide ceramic closed impeller as described in any one of claims 1-5, characterized in that, The specific steps are as follows: 1) The front cover plate ceramic part (1), the rear cover plate ceramic part (4) and the ceramic blade assembly (3) are respectively manufactured by reaction sintering process; 2) Process the metal skeleton (3); 3) Insert each fan-shaped plate component of the ceramic blade assembly (3) between the front support ring plate and the rear support plate of the metal frame (3) and glue them together to form an assembly, and make two adjacent fan-shaped components wrap around the stiffener plate respectively. 4) Attach the front cover ceramic part (1) to the front side of the front support ring plate of the metal frame (3), and attach the rear cover ceramic part (4) to the rear side of the rear support plate of the metal frame (3). 5) The bonded impeller is cured and molded to obtain the finished closed impeller.

7. The method for manufacturing a large reaction-sintered silicon carbide ceramic closed impeller as described in claim 1, characterized in that, The curing conditions in step 5) are: curing at 150℃~160℃ for 2~3 hours.

8. The method for manufacturing a large reaction-sintered silicon carbide ceramic closed impeller as described in claim 1, characterized in that, Each of the fan-shaped plate components of the front cover ceramic part (1), the rear cover ceramic part (4) and the ceramic blade assembly (3) is made by mixing silicon carbide powder and phenolic resin at a mass ratio of 9:1 and then sintering at 1350℃ for 3 hours.

9. The method for manufacturing a large reaction-sintered silicon carbide ceramic closed impeller as described in claim 1, characterized in that, The metal frame (3) is made of 316L stainless steel.

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