Stainless steel-based acid-resistant pump flow passage component and forming method thereof

Abstract

The invention discloses a stainless steel-based acid-resistant pump flow passage component and a forming method thereof, and belongs to the technical field of material processing. The method comprises the following steps: S1, stainless steel smelting; s2, preparing a flow passage component blank; s3, stainless steel liquid infiltration casting is conducted, specifically, the stainless steel liquid obtained in the step S1 is poured into the flow passage component blank obtained in the step S2, pressure is applied, the stainless steel liquid permeates into the flow passage component blank, and the stainless steel-based acid-resistant pump flow passage component is obtained; and S4, the stainless steel-based acid-resistant pump flow passage component obtained in the step S3 is subjected to shot blasting treatment. The flow passage component with excellent corrosion resistance and wear resistance is prepared through the simple, convenient, low-cost and high-efficiency forming method, the flow passage component can meet the application requirements of extreme complex working conditions, and the flow passage component has excellent applicability in corrosion-resistant equipment flow passage components.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of material processing, and relates to a stainless steel-based acid-resistant pump flow part and a forming method thereof. BACKGROUND

[0002] Stainless steel is a key structural material for acid-resistant pump flow parts in the fields of chemical industry, metallurgy and electric power due to its excellent corrosion resistance and comprehensive mechanical properties, and is widely used in high-corrosion working conditions. In corrosive media, stainless steel can effectively resist the corrosion of various acids and has good casting and processing performance, and is suitable for manufacturing acid-resistant pump flow parts with complex structures. However, with the development of related technologies, the working conditions are becoming more and more complex. For the flow part, in addition to high corrosion, it also involves high wear conditions. Pure stainless steel is significantly insufficient in wear resistance due to the lack of hard phases, resulting in severe wear of the stainless steel flow part under the scouring of high-speed fluid containing solid particles during actual use, and a sharp decrease in service life. The pure stainless steel flow part can only be used for about a week under the combined action of corrosion and wear in some chemical plants, and needs to be replaced.

[0003] Therefore, the pure stainless steel or conventional stainless steel-based material flow part has been difficult to meet the long-term service requirement.

[0004] To improve the service performance of stainless steel in strong abrasive and corrosive conditions, two types of technical approaches are currently used: one is to prepare a wear-resistant and corrosion-resistant coating on the surface of stainless steel, such as forming a ceramic or cermet composite layer by thermal spraying, laser cladding or plating technology; the other is to directly introduce ceramic particles into the stainless steel matrix by powder metallurgy, in-situ synthesis or casting-infiltration process to form a whole composite material. The former relies on the interface bonding between the coating and the matrix, and is prone to peeling under complex structure or thermal cycling conditions due to insufficient bonding force. The latter involves the interface compatibility and bonding strength between the reinforcing phase and the metal matrix, and especially when the component shape is complex and the reinforcing phase is unevenly distributed, interface defects are easily generated, resulting in a decrease in material performance.

[0005] Ceramic materials have high hardness, excellent chemical stability and wear resistance, especially silicon carbide and tungsten carbide ceramic particles can still maintain relatively stable physical and chemical properties at high temperatures. The composite material obtained by introducing ceramic materials into stainless steel-based materials not only retains the corrosion resistance and toughness of the stainless steel matrix, but also introduces the wear resistance and high-temperature resistance of ceramic materials, significantly improving the comprehensive performance of the composite material. Therefore, introducing ceramic particles into stainless steel matrix to form a composite material has become an important way to break through the performance boundary of existing materials.

[0006] In the whole composite material preparation process, although the traditional preform method can realize the introduction of the reinforcing phase, its process usually includes preform preparation, assembly, pouring and other links, and has problems of complex process, high cost, low efficiency and the like, especially for the acid-proof pump over-flow components with complex flow channel or cavity structure, the forming adaptability and interface control ability of the traditional preform method are poor. On the other hand, in the infiltration casting process, the binder or paint is easily decomposed to produce gas under high temperature conditions, finally resulting in defects such as pores and inclusions in the over-flow component, and the wettability of the metal liquid is poor, the metal matrix and the reinforcing phase are mainly combined by mechanical bonding, and the degree of metallurgical bonding is low, under complex stress, cracks, oxidation or composition segregation are easily generated at the interface, which becomes the channel for preferential corrosion, and seriously, the metal matrix and the reinforcing phase are separated, so that the comprehensive performance of the composite material is lost, and thus the performance of the acid-proof pump over-flow component formed by the traditional infiltration casting process is usually lower than that of the pure stainless steel matrix.

[0007] Therefore, in view of the application requirements of the acid-proof pump over-flow component under strong corrosion-wear working conditions, it is necessary to provide a stainless steel-based acid-proof pump over-flow component and a forming method thereof, to optimize the ease of use and adaptability of the forming method, and to strengthen the interface metallurgical bonding strength between the reinforcing phase material and the stainless steel matrix, so that the acid-proof pump over-flow component can fully play its comprehensive performance and have better application effect under strong corrosion-wear working conditions. SUMMARY

[0008] In order to overcome the problems in the background art, the present application optimizes the forming method, reduces the complexity of the forming method, and thus reduces the cost of the forming method, improves the forming efficiency, improves the adaptability of the forming method to complex over-flow component structures, and through the optimization of the stainless steel liquid and the forming process, an acid-proof pump over-flow component with high strength bonding between the reinforcing phase and the stainless steel matrix is prepared, the comprehensive performance of the over-flow component such as wear resistance and high temperature stability is effectively strengthened, and the service life of the over-flow component under extreme complex working conditions is prolonged.

[0009] In order to achieve the above-mentioned purpose, the present application realizes the following technical scheme: The present application provides a forming method of a stainless steel-based acid-proof pump over-flow component, which comprises the following steps: S1: stainless steel smelting: step-by-step smelting is performed on scrap steel, low-carbon chromium iron, metallic nickel, silicon-iron alloy, manganese-iron alloy and molybdenum-iron alloy as raw materials to obtain a stainless steel liquid.

[0010] S2: over-flow component blank preparation: S2.1: place the foam model in the self-hardening resin sand box, vibrate and compact, then take out the foam model, and place the self-hardening resin sand box to form the over-flow component skeleton.

[0011] S2.2: Layered coating of yttrium stabilized zirconia based refractory coating on the outer surface of the flow component skeleton obtained in step S2.1.

[0012] S2.3: Mixing and stirring of the reinforcing phase particles, anhydrous ethanol and polyacrylate ethanol solution to obtain a suspension state composite coating, then layered coating of the suspension state composite coating on the yttrium stabilized zirconia refractory coating surface and ignition drying.

[0013] The reinforcing phase particles include ceramic materials such as silicon carbide, tungsten carbide, molybdenum carbide, tungsten powder, chromium powder, etc. When the reinforcing phase particles are a mixture of multiple substances, the substances are mixed in any ratio, and the purity of each individual substance is not less than 99.8%.

[0014] S2.4: Directional infrared heating of the flow component skeleton coated with the composite coating of step 2.3 to obtain a flow component blank.

[0015] S3: Stainless steel liquid infiltration casting: pouring the stainless steel liquid obtained in step S1 into the flow component blank of step S2 and applying pressure to allow the stainless steel liquid to penetrate into the flow component blank to obtain a stainless steel based acid resistant pump flow component.

[0016] S4: Shot blasting treatment of the stainless steel based acid resistant pump flow component obtained in step S3.

[0017] As a preferred embodiment, in step S1, the process of step-by-step melting is as follows: scrap steel, low-carbon chromium iron, and metallic nickel are preheated to 600-800°C under the protection of an inert gas atmosphere and held for 15 minutes; then the temperature is raised to 1450-1500°C and held for 10-20 minutes to oxidize phosphorus and form molten slag that floats to the surface to complete the initial dephosphorization; then the temperature is raised to 1520-1550°C, and ferrosilicon alloy is added for pre-deoxidation treatment for 5-8 minutes, followed by the addition of ferromanganese alloy and ferromolybdenum alloy for alloying for 8-12 minutes; finally, 0.01%-0.05% of metallic aluminum based on the total mass of the raw materials is added for stirring for 3-5 minutes for final deoxidation, and after standing for 5-10 minutes and slag removal, the temperature of the molten liquid is adjusted to 1500-1520°C for holding, obtaining the stainless steel liquid.

[0018] The melting is carried out using an induction melting furnace, in which, under the condition of inert gas protection, the phosphorus in the molten pool reacts with the furnace lining material (usually containing CaO, MgO, etc. alkaline oxides) to generate calcium phosphate slag that floats to the surface of the molten pool, achieving initial dephosphorization.

[0019] The subsequent addition of ferrosilicon alloy, ferromanganese alloy, ferromolybdenum alloy, etc. can remove oxygen in the molten pool, promote the floating of inclusions, prevent rephosphorization, and allow more inclusions to be removed by slag removal.

[0020] Preferably, the chemical composition of the stainless steel liquid, by weight percentage, includes: C: 0.03%–0.08%, Si: 0.3%–1.0%, Mn: 1.0%–2.0%, Cr: 17.0%–19.0%, Ni: 8.0%–10.5%, Mo: 0.1%–0.3%, with the balance being iron and unavoidable impurities.

[0021] Preferably, in step S2.1, the settling time is 60 minutes.

[0022] Preferably, in step S2.2, the thickness of the coating formed after the refractory coating is applied is 1~3mm, and after the refractory coating is applied, it is dried under hot air conditions of 80~100℃ for 10~15 minutes to form a coating.

[0023] Preferably, in step S2.3, the polyacrylate ethanol solution has a mass concentration of 5% to 10%, and the reinforcing phase particles, anhydrous ethanol, and polyacrylate ethanol solution are mixed and stirred in a mass ratio of reinforcing phase particles: anhydrous ethanol: polyacrylate ethanol solution = 7:2:1, with a stirring speed of 400 to 600 r / min and a stirring time of 1 to 2 h.

[0024] The particle size of the reinforcing phase is 45~50μm.

[0025] In step 2.3, the suspended composite coating is applied to the surface of the flow component skeleton in 2 to 3 layers. After each layer of composite coating is applied, an ignition drying is performed. Each ignition drying process lasts for 30 to 60 seconds, and the thickness of each layer of composite coating is 0.5 to 1.5 mm.

[0026] Preferably, in step S2.4, the infrared heating temperature is 400°C, the heating time is 6 minutes, and the holding time is 1.5 minutes.

[0027] By heating and heat preservation, the overall temperature of the flow component billet is raised to 400℃, which reduces the temperature difference between the flow component billet and the molten metal during the subsequent infiltration casting process. This avoids cracks caused by excessive temperature difference during infiltration casting, which would result in uneven surface of the flow component.

[0028] Preferably, in step S3, the pressure during the pouring process is controlled at 0.2~0.5MPa.

[0029] Preferably, in step S4, the shot size is 0.8~1.2mm, the shot spraying speed is 60~80m / s, and the shot blasting time is 5~8 minutes.

[0030] In another aspect, the present invention also proposes a flow-through component formed by the above molding method, which, when applied in chemical corrosion-resistant equipment, can exhibit excellent service performance and service life under corrosion-wear conditions.

[0031] The beneficial effects of this invention are: 1. This invention significantly improves the purity, fluidity, and corrosion resistance of molten stainless steel by using stepwise temperature-controlled melting and precise alloying, combined with an ultra-low carbon (C: 0.03%~0.08%), high chromium-nickel (Cr: 17%~19%, Ni: 8%~10.5%), and molybdenum-strengthened (Mo: 0.1%~0.3%) composition system. The low carbon content effectively inhibits carbide precipitation, the high chromium-nickel content ensures the stability of the passivation film, and the stepwise temperature-controlled melting reduces inclusions. This provides molten stainless steel with excellent high-temperature stability and good wettability for subsequent infiltration casting, which is conducive to promoting high-strength metallurgical bonding between the reinforcing phase and the metal matrix interface, and enhancing the service performance and lifespan of flow components under corrosion-wear conditions.

[0032] 2. This invention uses ethanol as a solvent and utilizes ignition drying to form a uniform porous structure, providing abundant penetration channels for stainless steel melt infiltration casting, improving the penetration efficiency of stainless steel melt, effectively promoting the formation of metallurgical bond between the reinforcing phase and the metal matrix, and effectively solving the problem of easy detachment between the reinforcing phase and the metal matrix of composite materials.

[0033] 3. This invention utilizes the flammability of ethanol to ignite and dry the coating formed by the composite coating, thereby achieving rapid curing of the coating. This eliminates the need for a time-consuming drying process, effectively reducing the production cycle and improving production efficiency. It also results in more uniform pores in the formed coating. Furthermore, the polyacrylate ethanol solution undergoes high-temperature decomposition and complete volatilization during combustion and infrared pre-firing, effectively avoiding organic residues and ensuring the purity and bonding reliability of the interface between the enhanced phase and the metal collective.

[0034] 4. By carefully selecting hard reinforcing phase particles with a particle size of 45-50μm and controlling the proportion of reinforcing phase particles, solvent, and binder, this invention can form a dense barrier after the stainless steel liquid penetrates, effectively inhibiting the penetration of acid etching media, thereby giving the flow-through components excellent corrosion resistance and wear resistance.

[0035] 5. This invention significantly improves the high-temperature stability and thermal shock resistance of the flow-through component surface by coating with yttrium-stabilized zirconia-based refractory coating. It effectively eliminates the sand holes in the self-hardening resin sand box where the composite coating enters, avoiding sand hole defects on the surface of the flow-through component. It provides a uniform and stable refractory interface for the molten metal infiltration casting process, preventing the high-temperature stainless steel liquid from reacting with the resin sand during infiltration casting. This lays a uniform and stable base for the subsequent coating of composite coating, helping to reduce gas evolution and inclusion formation during casting, thereby improving the overall consistency of the quality and performance of the flow-through component.

[0036] 6. This invention uses self-hardening resin sand molding to ensure that the flow-through components can achieve complex structural shapes and meet the required precision.

[0037] 7. The unused ethanol solvent in this invention can be recycled and reused, reducing the burden of waste liquid treatment. Furthermore, the cost of ceramic reinforcing phases such as silicon carbide is low, and material loss can be effectively reduced through ratio optimization, which is conducive to saving the overall production cost of flow-through components.

[0038] 8. The present invention uses a dual-box molding scheme of foam model + self-hardening resin sand box, which has high efficiency and reliability for industrial mass production. At the same time, the method of the present invention has the advantages of low cost and simple operation. The flow-through components prepared by the method of the present invention have excellent comprehensive performance and are suitable for industrial promotion and application. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the process flow of the present invention.

[0040] Figure 2 This is a side cross-sectional microstructure diagram of the flow-through component prepared in Example 1 of the present invention.

[0041] Figure 3 This is a side cross-sectional microstructure diagram of the flow-through component prepared in Example 2 of the present invention.

[0042] Figure 4 This is a side cross-sectional microstructure diagram of the flow-through component prepared in Example 3 of the present invention.

[0043] Figure 5 This is a side cross-sectional microstructure diagram of the flow-through component prepared in Example 4 of the present invention.

[0044] Figure 6 This is a side cross-sectional microstructure diagram of the flow-through component prepared in Example 5 of the present invention. Detailed Implementation

[0045] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0046] Example 1 This embodiment uses the following method to mold the acid-resistant pump flow-through component: (1) Stainless steel smelting: According to the chemical composition of stainless steel liquid by weight percentage as C: 0.03%, Si: 0.3%, Mn: 1.0%, Cr: 17.0%, Ni: 8.0%, Mo: 0.1%, with the balance being Fe and unavoidable impurities, scrap steel, low-carbon ferrochrome, nickel plate, ferrosilicon alloy, ferromanganese alloy, and ferromolybdenum alloy raw materials are weighed respectively. First, the scrap steel, low-carbon ferrochrome, and nickel plate are placed in a medium-frequency induction melting furnace, preheated to 600℃ under an argon protective atmosphere and held for 15 minutes, and then the temperature is increased. The solution is heated to 1450℃ for 10 minutes to oxidize phosphorus and form slag that floats to the surface, thus completing the initial dephosphorization. Then, the temperature is raised to 1520℃, and ferrosilicon is added for pre-deoxidation treatment for 5 minutes. Then, ferromanganese and ferromolybdenum are added for alloying for 8 minutes. At the same time, electromagnetic stirring is used to ensure the uniformity of the molten pool composition. Finally, aluminum wire accounting for 0.01% of the total mass of raw materials is added and stirred for 3 minutes for final deoxidation. After final deoxidation, the solution is allowed to stand for 5 minutes to allow the inclusions to float to the surface. After thoroughly removing the slag, the temperature is adjusted to 1500℃ and the stainless steel liquid is kept at that temperature.

[0047] (2) Preparation of flow component blanks: ① Place the high-density foam model, which has been machined by computer numerical control (CNC), into a self-hardening resin sand box. Place the self-hardening resin sand box on a vibration table and vibrate it until the self-hardening resin sand is compacted. Then remove the foam model and let the self-hardening resin sand stand for 60 minutes to allow the sand mold to fully solidify and form a precisely structured skeleton for the flow-through components.

[0048] ② A layer of yttrium-stabilized zirconia-based refractory coating is uniformly coated on the outer surface of the flow component skeleton using a dip-coating method, with the coating thickness controlled at 1 mm. Subsequently, it is placed in an 80°C hot air circulating oven for drying for 10 minutes to form a dense refractory and anti-sand-hole coating.

[0049] ③ Weigh out polyacrylate powder and dissolve it in anhydrous ethanol. Place the solution in a mechanical stirrer and stir at a constant speed of 400 r / min for 2 hours to prepare a 5% polyacrylate ethanol solution.

[0050] ④ Weigh the reinforcing phase particles (metallic Cr powder, particle size 45μm, purity ≥99.8%), anhydrous ethanol, and 5% polyacrylate ethanol solution according to the mass ratio of reinforcing phase particles: anhydrous ethanol: polyacrylate ethanol solution = 7:2:1. Place them in a sealed stirring container and stir at 400r / min for 1h to obtain a uniformly dispersed and stable suspended chromium powder composite coating.

[0051] ⑤ Apply the chromium powder composite coating evenly to the refractory and anti-sand-hole coating surface using a spray gun. Apply two coats, each with a thickness controlled at 0.5 mm. After each coat is applied, immediately ignite it with an open flame, allowing it to burn for approximately 30 seconds. The ethanol combustion process rapidly cures the coating, forming a robust and porous composite coating.

[0052] ⑥ Infrared Preheating: The flow component skeleton with the composite coating is transferred to the infrared heating station for directional radiation heating. The power of the infrared heater is controlled to uniformly raise the surface temperature of the composite coating to 400℃ within 6 minutes and maintain it for 1.5 minutes. This process effectively purifies and activates the chromium powder surface, creating optimal conditions for its subsequent metallurgical bonding with molten steel.

[0053] (3) Stainless steel liquid infiltration casting: Stainless steel liquid at 1500℃ and with a viscosity of about 1.5 Pas is poured into the flow component billet through a gating system under an infiltration pressure of 0.2 MPa. The molten steel infiltrates the composite coating, and some chromium powder dissolves and diffuses, forming a metal-ceramic composite layer on the surface of the flow component billet with a chromium content much higher than that of the stainless steel substrate. After the casting cools to room temperature in the mold, it is unpacked and removed to obtain the flow component.

[0054] (4) The surface of the flow component is shot blasted using a shot blasting machine. The shot blasting material is cast steel shot with a particle size of 0.8 mm, the blasting speed is 60 m / s, and the processing time is 5 minutes, so as to obtain a smooth surface and a high-performance metal-ceramic composite flow component.

[0055] The microstructure of the side cross-section of the flow-through component prepared in this embodiment was observed, and the results are as follows: Figure 2 As shown.

[0056] pass Figure 2 It can be seen that the reinforcing phase particles exhibit a highly uniform distribution in the matrix, without obvious segregation, agglomeration, or local enrichment, forming a continuous and stable three-dimensional spatial distribution network. From a microscopic perspective, the interface between the reinforcing phase and the metal matrix is ​​clear and complete, exhibiting good compatibility, without obvious cracks, reaction transition layers, or other defects, demonstrating excellent metallurgical bonding characteristics.

[0057] The surface of the flow-through components was subjected to Vickers hardness testing and corrosion resistance testing under simulated acid pump conditions using a fully automated microhardness tester and electrochemical workstation. Furthermore, a beam-type bending test specimen with an interface zone was designed according to the ISO 7438 standard, and the composite layer was tested for peeling failure through a three-point bending test.

[0058] The surface Vickers hardness of the flow-through component prepared in this embodiment was tested to be 589.9 HV, and the current density in a mixed etching solution containing 2.2 wt% NaCl and 0.2 wt% HF (pH=2.2) was 1.626 × 10⁻⁶.-3 A / cm 2 The three-point bending test was applied to a critical stress of 350 MPa. No peeling phenomenon was observed at the interface between the reinforcing phase and the stainless steel matrix, proving that the interface bonding reliability meets the requirements of the ISO 13781 engineering component standard.

[0059] Example 2 This embodiment uses the following method to mold the acid-resistant pump flow-through component: (1) Stainless steel smelting: According to the chemical composition of the molten stainless steel as follows (weight percentage): C: 0.08%, Si: 1.0%, Mn: 2.0%, Cr: 19.0%, Ni: 10.5%, Mo: 0.3%, with the balance being Fe and unavoidable impurities, scrap steel, low-carbon ferrochrome, nickel plate, ferrosilicon alloy, ferromanganese alloy, and ferromolybdenum alloy raw materials are weighed separately. First, the scrap steel, low-carbon ferrochrome, and nickel plate are placed in a medium-frequency induction melting furnace, preheated to 800℃ under an argon protective atmosphere, and held for 15 minutes. Then, the temperature is raised to The solution is held at 1500℃ for 20 minutes to oxidize phosphorus and form slag that floats to the surface, thus completing the initial dephosphorization. Then, the temperature is raised to 1550℃, and ferrosilicon is added for pre-deoxidation treatment for 8 minutes. Ferromanganese and ferromolybdenum are then added for alloying for 12 minutes. At the same time, electromagnetic stirring is used to ensure uniform composition of the molten pool. Finally, aluminum wire accounting for 0.05% of the total mass of raw materials is added and stirred for 5 minutes for final deoxidation. After final deoxidation, the solution is allowed to stand for 10 minutes to allow inclusions to float to the surface. After thoroughly removing the slag, the temperature is adjusted to 1520℃ and the stainless steel liquid is kept at that temperature.

[0060] (2) Preparation of flow component blanks: ① Place the high-density foam model, which has been machined by computer numerical control (CNC), into a self-hardening resin sand box. Place the self-hardening resin sand box on a vibration table and vibrate it until the self-hardening resin sand is compacted. Then remove the foam model and let the self-hardening resin sand stand for 60 minutes to allow the sand mold to fully solidify and form a precisely structured skeleton for the flow-through components.

[0061] ② A layer of yttrium-stabilized zirconia-based refractory coating is uniformly coated on the outer surface of the flow component skeleton using a dip-coating method, with the coating thickness controlled at 3 mm. Subsequently, it is placed in a 100°C hot air circulating oven for drying for 15 minutes to form a dense refractory and anti-sand-hole coating.

[0062] ③ Weigh out polyacrylate powder and dissolve it in anhydrous ethanol. Place the solution in a mechanical stirrer and stir at a constant speed of 600 r / min for 3 hours to prepare a 10% polyacrylate ethanol solution.

[0063] ④ Weigh the reinforcing phase particles (molybdenum silicide powder, particle size 50μm, purity ≥99.8%), anhydrous ethanol, and a 10% polyacrylate ethanol solution according to the mass ratio of reinforcing phase particles: anhydrous ethanol: polyacrylate ethanol solution = 7:2:1. Place them in a sealed stirring container and stir at 600r / min for 2h to obtain a uniformly dispersed and stable suspended molybdenum silicide powder composite coating.

[0064] ⑤ Apply the molybdenum siliconized powder composite coating evenly to the refractory and anti-sand-hole coating surface using a spray gun. Apply three coats, each with a thickness controlled at 1.5 mm. After each coat is applied, immediately ignite it with an open flame, allowing it to burn for approximately 60 seconds. The ethanol combustion process rapidly cures the coating, forming a robust and porous composite coating.

[0065] ⑥ Infrared Preheating: The flow component skeleton with the composite coating is transferred to the infrared heating station for directional radiation heating. The power of the infrared heater is controlled to uniformly raise the surface temperature of the composite coating to 400℃ within 6 minutes and maintain it for 1.5 minutes. This process effectively purifies and activates the surface of the molybdenum silicide powder, creating optimal conditions for its subsequent metallurgical bonding with molten steel.

[0066] (3) Stainless steel liquid infiltration casting: Stainless steel liquid at 1520℃ and with a viscosity of approximately 1.3 Pas is poured into the flow component billet through a gating system under an infiltration pressure of 0.5 MPa. The molten steel infiltrates the composite coating, and some molybdenum silicide powder dissolves and diffuses, forming a metal-ceramic composite layer on the surface of the flow component billet with a molybdenum silicide content much higher than that of the stainless steel substrate. After the casting cools to room temperature in the mold, it is unpacked and removed to obtain the flow component.

[0067] (4) The surface of the flow component is shot blasted using a shot blasting machine. The shot blasting material is cast steel shot with a particle size of 1.2 mm. The blasting speed is 80 m / s and the treatment time is 8 minutes to obtain a smooth surface and a high-performance metal-ceramic composite flow component.

[0068] The microstructure of the side cross-section of the flow-through component prepared in this embodiment was observed, and the results are as follows: Figure 3 As shown.

[0069] pass Figure 3 It can be seen that the reinforcing phase particles are uniformly distributed in the matrix in a highly dispersed form, and no obvious aggregation, segregation or excessive local concentration was observed. The interface between the reinforcing phase and the metal matrix is ​​dense and complete, and the two phases exhibit excellent wetting behavior and material compatibility. No defects such as microcracks or excessive reaction layers were observed in the interface area, showing excellent metallurgical bonding quality.

[0070] The surface of the flow-through components was subjected to Vickers hardness testing and corrosion resistance testing under simulated acid pump conditions using a fully automated microhardness tester and electrochemical workstation. Furthermore, a beam-type bending test specimen with an interface zone was designed according to the ISO 7438 standard, and the composite layer was tested for peeling failure through a three-point bending test.

[0071] The surface Vickers hardness of the flow-through component prepared in this embodiment was tested to be 577.8 HV, and the current density in a mixed etching solution containing 2.2 wt% NaCl and 0.2 wt% HF (pH=2.2) was 2.76 × 10⁻⁶. -3 A / cm 2 The three-point bending test was applied to a critical stress of 350 MPa. No peeling phenomenon was observed at the interface between the reinforcing phase and the stainless steel matrix, proving that the interface bonding reliability meets the requirements of the ISO 13781 engineering component standard.

[0072] Example 3 This embodiment uses the following method to mold the acid-resistant pump flow-through component: (1) Stainless steel smelting: According to the chemical composition of the molten stainless steel as follows (weight percentage): C: 0.05%, Si: 0.6%, Mn: 1.5%, Cr: 18.2%, Ni: 9.0%, Mo: 0.2%, with the balance being Fe and unavoidable impurities, scrap steel, low-carbon ferrochrome, nickel plate, ferrosilicon alloy, ferromanganese alloy, and ferromolybdenum alloy raw materials are weighed separately. First, the scrap steel, low-carbon ferrochrome, and nickel plate are placed in a medium-frequency induction melting furnace, preheated to 650°C under an argon protective atmosphere, and held for 15 minutes. Then, the temperature is raised to The solution is held at 1480℃ for 15 minutes to oxidize phosphorus and form slag that floats to the surface, thus completing the initial dephosphorization. Then, the temperature is raised to 1530℃, and ferrosilicon is added for pre-deoxidation treatment for 6 minutes. Then, ferromanganese and ferromolybdenum are added for alloying for 10 minutes. At the same time, electromagnetic stirring is used to ensure the uniformity of the molten pool composition. Finally, aluminum wire accounting for 0.03% of the total mass of raw materials is added and stirred for 4 minutes for final deoxidation. After final deoxidation, the solution is allowed to stand for 10 minutes to allow the inclusions to float to the surface. After thoroughly removing the slag, the temperature is adjusted to 1510℃ and the stainless steel liquid is held at that temperature.

[0073] (2) Preparation of flow component blanks: ① Place the high-density foam model, which has been machined by computer numerical control (CNC), into a self-hardening resin sand box. Place the self-hardening resin sand box on a vibration table and vibrate it until the self-hardening resin sand is compacted. Then remove the foam model and let the self-hardening resin sand stand for 60 minutes to allow the sand mold to fully solidify and form a precisely structured skeleton for the flow-through components.

[0074] ② A layer of yttrium-stabilized zirconia-based refractory coating is uniformly coated on the outer surface of the flow component skeleton using a dip-coating method, with the coating thickness controlled at 2 mm. Subsequently, it is placed in a 90℃ hot air circulating oven for drying for 12 minutes to form a dense refractory and anti-sand-hole coating.

[0075] ③ Weigh out polyacrylate powder and dissolve it in anhydrous ethanol. Place the solution in a mechanical stirrer and stir at a constant speed of 500 r / min for 2.5 hours to prepare a polyacrylate ethanol solution with a mass concentration of 8%.

[0076] ④ Weigh the reinforcing phase particles (silicon carbide powder, particle size 50μm, purity ≥99.8%), anhydrous ethanol, and 8% polyacrylate ethanol solution according to the mass ratio of reinforcing phase particles: anhydrous ethanol: polyacrylate ethanol solution = 7:2:1. Place them in a sealed stirring container and stir at 500r / min for 1.5h to obtain a uniformly dispersed and stable suspended silicon carbide powder composite coating.

[0077] ⑤ Apply the silicon carbide powder composite coating evenly to the refractory and anti-sand-hole coating surface using a spray gun. Apply three coats, each with a thickness controlled at 1 mm. After each coat is applied, immediately ignite it with an open flame, allowing it to burn for approximately 45 seconds. The ethanol combustion process rapidly cures the coating, forming a robust and porous composite coating.

[0078] ⑥ Infrared Preheating: The flow component skeleton with the composite coating is transferred to the infrared heating station for directional radiation heating. The power of the infrared heater is controlled to uniformly raise the surface temperature of the composite coating to 400℃ within 6 minutes and maintain it for 1.5 minutes. This process effectively purifies and activates the surface of the silicon carbide powder, creating optimal conditions for its subsequent metallurgical bonding with molten steel.

[0079] (3) Stainless steel liquid infiltration casting: Stainless steel liquid at 1510℃ and with a viscosity of approximately 1.3 Pas is poured into the flow component billet through a gating system under an infiltration pressure of 0.35 MPa. The molten steel infiltrates the composite coating, and some silicon carbide powder dissolves and diffuses, forming a metal-ceramic composite layer on the surface of the flow component billet with a silicon carbide content much higher than that of the stainless steel substrate. After the casting cools to room temperature in the mold, it is unpacked and removed to obtain the flow component.

[0080] (4) The surface of the flow component is shot blasted using a shot blasting machine. The shot blasting material is cast steel shot with a particle size of 1.0 mm, the blasting speed is 70 m / s, and the processing time is 6 minutes, so as to obtain a smooth surface and a high-performance metal-ceramic composite flow component.

[0081] The microstructure of the side cross-section of the flow-through component prepared in this embodiment was observed, and the results are as follows: Figure 4 As shown.

[0082] pass Figure 4It can be seen that the reinforcing phase particles exhibit a highly uniform distribution in the matrix, without obvious segregation, agglomeration, or local enrichment, forming a continuous and stable three-dimensional spatial distribution network. From a microscopic perspective, the interface between the reinforcing phase and the metal matrix is ​​clear and complete, exhibiting good compatibility, without obvious cracks, reaction transition layers, or other defects, demonstrating excellent metallurgical bonding characteristics.

[0083] The surface of the flow-through components was subjected to Vickers hardness testing and corrosion resistance testing under simulated acid pump conditions using a fully automated microhardness tester and electrochemical workstation. Furthermore, a beam-type bending test specimen with an interface zone was designed according to the ISO 7438 standard, and the composite layer was tested for peeling failure through a three-point bending test.

[0084] The surface Vickers hardness of the flow-through component prepared in this embodiment was tested to be 689.6 HV, and the current density in a mixed etching solution containing 2.2 wt% NaCl and 0.2 wt% HF (pH=2.2) was 2.773 × 10⁻⁶. -3 A / cm 2 The three-point bending test was applied to a critical stress of 350 MPa. No peeling phenomenon was observed at the interface between the reinforcing phase and the stainless steel matrix, proving that the interface bonding reliability meets the requirements of the ISO 13781 engineering component standard.

[0085] Example 4 This embodiment uses the following method to mold the acid-resistant pump flow-through component: (1) Stainless steel smelting: According to the chemical composition of stainless steel liquid by weight percentage as C: 0.07%, Si: 0.4%, Mn: 1.6%, Cr: 18.0%, Ni: 9.5%, Mo: 0.22%, with the balance being Fe and unavoidable impurities, scrap steel, low-carbon ferrochrome, nickel plate, ferrosilicon alloy, ferromanganese alloy, and ferromolybdenum alloy raw materials are weighed respectively. First, the scrap steel, low-carbon ferrochrome, and nickel plate are placed in a medium-frequency induction melting furnace, preheated to 750°C under an argon protective atmosphere and held for 15 minutes, and then the temperature is increased. The solution is heated to 1485℃ for 13 minutes to oxidize phosphorus and form slag that floats to the surface, thus completing the initial dephosphorization. The temperature is then raised to 1545℃, and ferrosilicon is added for pre-deoxidation treatment for 7 minutes. Ferromanganese and ferromolybdenum are then added for alloying for 11 minutes. Simultaneously, electromagnetic stirring is used to ensure uniform composition of the molten pool. Finally, aluminum wire accounting for 0.02% of the total mass of raw materials is added and stirred for 3 minutes for final deoxidation. After final deoxidation, the solution is allowed to stand for 8 minutes to allow inclusions to float to the surface. After thoroughly removing the slag, the temperature is adjusted to 1505℃ and the stainless steel liquid is kept at that temperature.

[0086] (2) Preparation of flow component blanks: ① Place the high-density foam model, which has been machined by computer numerical control (CNC), into a self-hardening resin sand box. Place the self-hardening resin sand box on a vibration table and vibrate it until the self-hardening resin sand is compacted. Then remove the foam model and let the self-hardening resin sand stand for 60 minutes to allow the sand mold to fully solidify and form a precisely structured skeleton for the flow-through components.

[0087] ② A layer of yttrium-stabilized zirconia-based refractory coating is uniformly coated on the outer surface of the flow component skeleton using a dip-coating method, with the coating thickness controlled at 1.8 mm. Subsequently, it is placed in an 88°C hot air circulating oven for drying for 15 minutes to form a dense refractory and anti-sand-hole coating.

[0088] ③ Weigh out polyacrylate powder and dissolve it in anhydrous ethanol. Place the solution in a mechanical stirrer and stir at a constant speed of 500 r / min for 2.2 hours to prepare a polyacrylate ethanol solution with a mass concentration of 8%.

[0089] ④ Weigh the reinforcing phase particles (W powder, particle size 47μm, purity ≥99.8%), anhydrous ethanol, and 8% polyacrylate ethanol solution according to the mass ratio of reinforcing phase particles: anhydrous ethanol: polyacrylate ethanol solution = 7:2:1. Place them in a sealed stirring container and stir at 600r / min for 2h to obtain a uniformly dispersed and stable suspended W powder composite coating.

[0090] ⑤ Apply the W-powder composite coating evenly to the refractory and anti-sand-hole coating surface using a spray gun. Apply two coats, each with a thickness controlled at 1.5 mm. After each coat is applied, immediately ignite it with an open flame, allowing it to burn for approximately 60 seconds. The ethanol combustion rapidly cures the coating, forming a robust and porous composite coating.

[0091] ⑥ Infrared Preheating: The flow-through component skeleton with the composite coating is transferred to the infrared heating station for directional radiation heating. The power of the infrared heater is controlled to uniformly raise the surface temperature of the composite coating to 400℃ within 6 minutes and maintain it for 1.5 minutes. This process effectively purifies and activates the W powder surface, creating optimal conditions for its subsequent metallurgical bonding with molten steel.

[0092] (3) Stainless steel liquid infiltration casting: Stainless steel liquid at 1505℃ and with a viscosity of approximately 1.3 Pas is poured into the flow component billet through a gating system under an infiltration pressure of 0.45 MPa. The molten steel infiltrates the composite coating, and some W powder dissolves and diffuses, forming a metal-ceramic composite layer on the surface of the flow component billet with a W content much higher than that of the stainless steel substrate. After the casting cools to room temperature in the mold, it is unpacked and removed to obtain the flow component.

[0093] (4) The surface of the flow component is shot blasted using a shot blasting machine. The shot blasting material is cast steel shot with a particle size of 1.0 mm, the blasting speed is 70 m / s, and the processing time is 8 minutes, so as to obtain a smooth surface and a high-performance metal-ceramic composite flow component.

[0094] The microstructure of the side cross-section of the flow-through component prepared in this embodiment was observed, and the results are as follows: Figure 5 As shown.

[0095] pass Figure 5 It can be seen that the reinforcing phase particles are uniformly distributed in the matrix in a highly dispersed form, and no obvious aggregation, segregation or excessive local concentration was observed. The interface between the reinforcing phase and the metal matrix is ​​dense and complete, and the two phases exhibit excellent wetting behavior and material compatibility. No defects such as microcracks or excessive reaction layers were observed in the interface area, showing excellent metallurgical bonding quality.

[0096] The surface of the flow-through components was subjected to Vickers hardness testing and corrosion resistance testing under simulated acid pump conditions using a fully automated microhardness tester and electrochemical workstation. Furthermore, a beam-type bending test specimen with an interface zone was designed according to the ISO 7438 standard, and the composite layer was tested for peeling failure through a three-point bending test.

[0097] The surface Vickers hardness of the flow-through component prepared in this embodiment was tested to be 631.3 HV, and the current density in a mixed etching solution containing 2.2 wt% NaCl and 0.2 wt% HF (pH=2.2) was 2.427 × 10⁻⁶. -3 A / cm 2 The three-point bending test was applied to a critical stress of 350 MPa. No peeling phenomenon was observed at the interface between the reinforcing phase and the stainless steel matrix, proving that the interface bonding reliability meets the requirements of the ISO 13781 engineering component standard.

[0098] Example 5 This embodiment uses the following method to mold the acid-resistant pump flow-through component: (1) Stainless steel smelting: According to the chemical composition of stainless steel liquid by weight percentage as C: 0.055%, Si: 0.7%, Mn: 1.4%, Cr: 17.5%, Ni: 8.8%, Mo: 0.15%, with the balance being Fe and unavoidable impurities, scrap steel, low-carbon ferrochrome, nickel plate, ferrosilicon alloy, ferromanganese alloy, and ferromolybdenum alloy raw materials are weighed respectively. First, the scrap steel, low-carbon ferrochrome, and nickel plate are placed in a medium-frequency induction melting furnace, preheated to 660℃ under an argon protective atmosphere and held for 15 minutes, and then the temperature is increased. The solution is held at 1475℃ for 18 minutes to oxidize phosphorus and form slag that floats to the surface, thus completing the initial dephosphorization. The temperature is then raised to 1525℃, and ferrosilicon is added for pre-deoxidation treatment for 8 minutes. Ferromanganese and ferromolybdenum are then added for alloying for 11 minutes. Simultaneously, electromagnetic stirring is used to ensure uniform composition of the molten pool. Finally, aluminum wire (0.01% of the total mass of raw materials) is added and stirred for 5 minutes for final deoxidation. After final deoxidation, the solution is allowed to stand for 9 minutes to allow inclusions to float to the surface. After thoroughly removing the slag, the temperature is adjusted to 1505℃ and the stainless steel liquid is held at that temperature.

[0099] (2) Preparation of flow component blanks: ① Place the high-density foam model, which has been machined by computer numerical control (CNC), into a self-hardening resin sand box. Place the self-hardening resin sand box on a vibration table and vibrate it until the self-hardening resin sand is compacted. Then remove the foam model and let the self-hardening resin sand stand for 60 minutes to allow the sand mold to fully solidify and form a precisely structured skeleton for the flow-through components.

[0100] ② A layer of yttrium-stabilized zirconia-based refractory coating is uniformly coated on the outer surface of the flow component skeleton using a dip-coating method, with the coating thickness controlled at 2.2 mm. Subsequently, it is placed in a 92℃ hot air circulating oven for drying for 11 minutes to form a dense refractory and anti-sand-hole coating.

[0101] ③ Weigh out polyacrylate powder and dissolve it in anhydrous ethanol. Place the solution in a mechanical stirrer and stir at a constant speed of 580 r / min for 2.2 hours to prepare a 7% polyacrylate ethanol solution.

[0102] ④ Weigh the reinforcing phase particles (W powder, particle size 45μm, purity ≥99.8%), anhydrous ethanol, and a 7% polyacrylate ethanol solution according to the mass ratio of reinforcing phase particles: anhydrous ethanol: polyacrylate ethanol solution = 7:2:1. Place them in a sealed stirring container and stir at 580r / min for 2h to obtain a uniformly dispersed and stable suspended W powder composite coating.

[0103] ⑤ Apply the W-powder composite coating evenly to the refractory and anti-sand-hole coating surface using a spray gun. Apply three coats, each with a thickness controlled at 1.0 mm. After each coat is applied, immediately ignite it with an open flame, allowing it to burn for approximately 55 seconds. The ethanol combustion process rapidly cures the coating, forming a robust and porous composite coating.

[0104] ⑥ Infrared Preheating: The flow-through component skeleton with the composite coating is transferred to the infrared heating station for directional radiation heating. The power of the infrared heater is controlled to uniformly raise the surface temperature of the composite coating to 400℃ within 6 minutes and maintain it for 1.5 minutes. This process effectively purifies and activates the W powder surface, creating optimal conditions for its subsequent metallurgical bonding with molten steel.

[0105] (3) Stainless steel liquid infiltration casting: Stainless steel liquid at 1505℃ and with a viscosity of approximately 1.45 Pas is poured into the flow component billet through a gating system under an infiltration pressure of 0.25 MPa. The molten steel infiltrates the composite coating, and some W powder dissolves and diffuses, forming a metal-ceramic composite layer on the surface of the flow component billet with a W content much higher than that of the stainless steel substrate. After the casting cools to room temperature in the mold, it is unpacked and removed to obtain the flow component.

[0106] (4) The surface of the flow component is shot blasted using a shot blasting machine. The shot blasting material is cast steel shot with a particle size of 0.8 mm, the blasting speed is 80 m / s, and the processing time is 5 minutes, so as to obtain a smooth surface and a high-performance metal-ceramic composite flow component.

[0107] The microstructure of the side cross-section of the flow-through component prepared in this embodiment was observed, and the results are as follows: Figure 6 As shown.

[0108] pass Figure 6 It can be seen that the reinforcing phase particles exhibit a highly uniform distribution in the matrix, without obvious segregation, agglomeration, or local enrichment, forming a continuous and stable three-dimensional spatial distribution network. From a microscopic perspective, the interface between the reinforcing phase and the metal matrix is ​​clear and complete, exhibiting good compatibility, without obvious cracks, reaction transition layers, or other defects, demonstrating excellent metallurgical bonding characteristics.

[0109] The surface of the flow-through components was subjected to Vickers hardness testing and corrosion resistance testing under simulated acid pump conditions using a fully automated microhardness tester and electrochemical workstation. Furthermore, a beam-type bending test specimen with an interface zone was designed according to the ISO 7438 standard, and the composite layer was tested for peeling failure through a three-point bending test.

[0110] The surface Vickers hardness of the flow-through component prepared in this embodiment was tested to be 728.5 HV, and the current density in a mixed etching solution containing 2.2 wt% NaCl and 0.2 wt% HF (pH=2.2) was 1.246 × 10⁻⁶.-3 A / cm 2 The three-point bending test was applied to a critical stress of 350 MPa. No peeling phenomenon was observed at the interface between the reinforcing phase and the stainless steel matrix, proving that the interface bonding reliability meets the requirements of the ISO 13781 engineering component standard.

[0111] Comparative Example 1 This comparative example directly uses conventional pure stainless steel current-flow components for performance testing. The results show that the Vickers hardness of the stainless steel current-flow components is 277.3 HV, and the current density is 3.81 × 10⁻⁶. -3 A / cm 2 .

[0112] As can be seen from the comparison between the examples and Comparative Example 1, the current flow component prepared by the present invention has significantly improved surface hardness, thereby giving it excellent wear resistance. At the same time, compared with Comparative Example 1, the current flow component of the present invention has a lower current density, thus giving it excellent acid resistance.

[0113] Comparative Example 2 This comparative example uses the same method as Example 1 to prepare the flow-through component, the difference being that: in this comparative example, water is used instead of ethanol as the solvent, and drying is used instead of ignition combustion to cure the composite layer.

[0114] A comparison of the examples and Comparative Example 2 shows that the traditional water-based casting infiltration process has significant disadvantages in terms of interface bonding strength, coating integrity, corrosion resistance and process efficiency. The interface bonding between the reinforcing phase and the stainless steel substrate is mainly mechanical, which is difficult to meet the requirements of high-intensity corrosion-wear conditions.

[0115] Comparative Example 3 This comparative example uses the same method as Example 1 to prepare the flow-through component, the difference being that this comparative example uses a one-time feeding and melting process: scrap steel, low-carbon ferrochrome, nickel plate, ferrosilicon, ferromanganese, ferromolybdenum, and other raw materials are added to the induction furnace all at once, heated directly to 1550°C under argon protection and held for 30 minutes, and then metallic aluminum is added for final deoxidation. The remaining steps are consistent with those in Example 1.

[0116] A comparison of the examples with Comparative Example 3 shows that the stainless steel molten steel in this comparative example has poor purity, compositional uniformity, and wettability. This directly leads to low interfacial bonding strength between the reinforcing phase and the stainless steel matrix, increased defects, and severely affects the service performance of the flow-through components under harsh operating conditions. This further demonstrates that the present invention employs step-by-step melting (preheating → dephosphorization → step alloying → final deoxidation) with precise temperature control and sequential addition of alloying elements to ensure the quality of the stainless steel molten steel. This provides a low-viscosity, highly active metal matrix for subsequent infiltration casting, which is one of the core guarantees for achieving high-strength metallurgical bonding and long-term corrosion and wear resistance.

[0117] Comparative Example 4 The flow-through component in this comparative example was prepared using the same method as in Example 1. The difference is that the coating and drying steps of the yttrium-stabilized zirconia-based refractory coating were omitted in this comparative example. After the self-hardening resin sand box was shaped and left to stand for 60 minutes to form the skeleton of the flow-through component, the reinforcing phase / ethanol / PAA composite coating was immediately coated on the surface of the self-hardening resin sand box and then ignited and dried.

[0118] A comparison of Examples 1 and Comparative Example 4 reveals that, due to the lack of protection from the yttrium-stabilized zirconia-based refractory coating, the resin sand mold is directly exposed to high-temperature molten steel (1500°C), resulting in severe thermal degradation and sintering. This leads to numerous sand adhesions, sintering scars, and sand hole defects on the casting surface. Compared to the surface of Example 1 using the yttrium-stabilized zirconia-based coating, the surface roughness of the flow component in Comparative Example 4 is high, with obvious sand grain embedding and surface pores. The resin sand mold without the yttrium-stabilized zirconia-based coating exhibits uneven pore size and unstable structure. During the ignition and drying process, the composite coating easily penetrates deep into the sand mold, leading to chaotic distribution, local enrichment, or depletion of the reinforcing phase. Simultaneously, during the infiltration casting of stainless steel, some resin sand decomposes thermally, generating gas that forms pores and inclusions in the metal-ceramic composite layer, disrupting interface integrity. The bonding between the reinforcing phase and the stainless steel matrix is ​​primarily mechanical, with a significantly lower metallurgical bond strength than that of Example 1.

[0119] Comparative Example 5 The comparative example uses the same method as Example 1 to prepare the flow-through component, the difference being that: the comparative example does not perform directional infrared heating, but directly dip-casts the flow-through component blank which has been ignited and dried and has a cured composite coating.

[0120] The performance of the current-carrying component prepared in this comparative example was tested, and the result showed a current density of 3.2 × 10⁻⁶. - 3 A / cm 2 Under the three-point bending test, the interface between the reinforcing phase and the stainless steel matrix peeled off at a stress of about 180-220 MPa, which is much lower than the 350 MPa in Example 1.

[0121] A comparison of the examples with Comparative Example 5 shows that without 400°C infrared preheating, the polyacrylate ethanol solution cannot be fully decomposed and volatilized. Residual organic matter cokes and decomposes during the high-temperature molten steel pouring, producing gas and carbonaceous residues, forming pores and inclusions at the interface. These defects become stress concentration points and corrosion initiation sources, severely degrading the purity and integrity of the interface. Simultaneously, the lack of directional infrared heating prevents the effective activation of the reinforcing phase particle surface, failing to remove adsorbed water vapor, gas, or trace contaminants. This results in a significant decrease in the wettability of the molten steel to the particles, making it difficult for the molten metal to uniformly coat the reinforcing phase. The interface bonding is primarily mechanical anchoring, rather than the metallurgical bonding achieved by this invention.

[0122] In summary, this invention combines step-by-step temperature control with ignition drying and directional infrared heating, and applies a yttrium-stabilized zirconia-based refractory coating to achieve high-quality molding of acid-resistant pump flow components. While ensuring simple molding of complex structures, it effectively improves the interfacial bonding strength and interface purity between the reinforcing phase and the stainless steel matrix, giving the flow components superior overall performance and enabling them to withstand long-term use under extreme corrosion and wear conditions.

[0123] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for molding a stainless steel-based acid-resistant pump flow component, characterized in that: The molding method includes the following steps: S1: Stainless steel smelting: Smelting in stages using scrap steel, low-carbon ferrochrome, metallic nickel, ferrosilicon alloy, ferromanganese alloy, and ferromolybdenum alloy as raw materials to obtain stainless steel liquid; S2: Preparation of flow-through component blank: S2.1: Place the foam model in the self-hardening resin sand box, vibrate to compact it, then remove the foam model and let the self-hardening resin sand box stand to form the skeleton of the flow-through component. S2.2: The outer surface of the flow component skeleton obtained in step S2.1 is coated with yttrium-stabilized zirconia-based refractory coating; S2.3: The reinforcing phase particles, anhydrous ethanol, and polyacrylate ethanol solution are mixed and stirred to obtain a suspension composite coating. The suspension composite coating is then layered and coated on the surface of the yttrium-stabilized zirconia refractory coating and then ignited and dried. S2.4: The flow-through component skeleton coated with composite coating in step 2.3 is subjected to directional infrared heating to obtain the flow-through component blank; S3: Stainless steel liquid infiltration casting: The stainless steel liquid obtained in step S1 is poured into the flow component blank in step S2 and pressure is applied to allow the stainless steel liquid to penetrate into the flow component blank, thereby obtaining a stainless steel-based acid-resistant pump flow component. S4: The stainless steel acid-resistant pump flow parts obtained in step S3 are subjected to shot blasting.

2. The molding method according to claim 1, characterized in that: In step S1, the specific process of step-by-step smelting is as follows: scrap steel, low-carbon ferrochrome, and metallic nickel are preheated to 600-800℃ under an inert gas atmosphere and held for 15 minutes; then the temperature is raised to 1450-1500℃ and held for 10-20 minutes to oxidize phosphorus and form slag that floats to the surface to complete the initial dephosphorization; then the temperature is raised to 1520-1550℃, and ferrosilicon alloy is added for pre-deoxidation treatment for 5-8 minutes, followed by the addition of ferromanganese alloy and ferromolybdenum alloy for alloying for 8-12 minutes; finally, 0.01%-0.05% of metallic aluminum by mass of the raw materials is added and stirred for 3-5 minutes for final deoxidation, and after standing for 5-10 minutes and removing the slag, the temperature of the molten liquid is adjusted to 1500-1520℃ and held to obtain stainless steel liquid.

3. The molding method according to claim 2, characterized in that: The chemical composition of the stainless steel liquid, by weight percentage, includes: C: 0.03%–0.08%, Si: 0.3%–1.0%, Mn: 1.0%–2.0%, Cr: 17.0%–19.0%, Ni: 8.0%–10.5%, Mo: 0.1%–0.3%, with the balance being iron and unavoidable impurities.

4. The molding method according to claim 1, characterized in that: In step S2.1, the settling time is 60 minutes.

5. The molding method according to claim 1, characterized in that: In step S2.2, the thickness of the coating formed after the refractory coating is applied is 1~3mm. After the refractory coating is applied, it is dried under hot air conditions of 80~100℃ for 10~15 minutes to form the coating.

6. The molding method according to claim 1, characterized in that: In step S2.3, the polyacrylate ethanol solution has a polyacrylate mass concentration of 5% to 10%. The reinforcing phase particles, anhydrous ethanol, and polyacrylate ethanol solution are mixed and stirred in a mass ratio of reinforcing phase particles: anhydrous ethanol: polyacrylate ethanol solution = 7:2:

1. The stirring speed is 400 to 600 r / min, and the stirring time is 1 to 2 h. The particle size of the reinforcing phase is 45~50μm.

7. The molding method according to claim 1, characterized in that: In step 2.3, the suspended composite coating is applied to the surface of the flow component skeleton in 2 to 3 layers. After each layer of composite coating is applied, an ignition drying is performed. Each ignition drying process lasts for 30 to 60 seconds, and the thickness of each layer of composite coating is 0.5 to 1.5 mm.

8. The molding method according to claim 1, characterized in that: In step S2.4, the infrared heating temperature is 400℃, the heating time is 6 minutes, and the holding time is 1.5 minutes.

9. The molding method according to claim 1, characterized in that: In step S3, the pressure during the pouring process is controlled at 0.2~0.5MPa.

10. The molding method according to claim 1, characterized in that: In step S4, the shot size is 0.8~1.2mm, the shot spraying speed is 60~80m / s, and the shot blasting time is 5~8 minutes.

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