An impeller for a double-suction pump and a method of manufacturing the same

Abstract

The application relates to the technical field of impellers, and discloses an impeller for a double-suction pump and a preparation method thereof. The impeller for the double-suction pump is composed of the following components in percentage by mass: C: 3.60-3.72%, Si: 1.85-2.05%, Mn: 0.35-0.60%, Mo: 0.22-0.30%, Cu: 0.75-0.95%, Ni: 0.45-0.55%, V: 0.30-0.42%, Ti: 0.04-0.08%, B: 0.03-0.06%, Sn: 0.008-0.012%, Mg: 0.025-0.040%, N: 0.015-0.025%, P: <=0.05%, S: <=0.03%, and the balance is Fe and inevitable impurities. The impeller provided by the application has high tensile strength and solves the technical problem of insufficient strength of the conventional impeller.

Description

Technical Field

[0001] This invention relates to the field of metal materials technology, specifically to an impeller for a double-suction pump and its preparation method. Background Technology

[0002] Double-suction centrifugal pumps, with their advantages of large flow rate and excellent axial force balance, are widely used in heavy-duty applications such as municipal water supply, mine drainage, farmland irrigation, and industrial circulating water transportation. The impeller, as the flow-through component, withstands the combined effects of media scouring, alternating hydraulic loads, and start-stop impact loads over extended periods. Conventional products are mostly cast from gray cast iron or ductile iron in a single piece, achieving mass production due to the low cost, good casting fluidity, and ease of machining of the cast iron matrix. The mechanical properties of cast iron materials are directly determined by the microstructure of the matrix, the graphite morphology, and the proportions of key alloying elements. Carbon and silicon elements dominate the graphitization precipitation process, manganese and sulfur elements regulate the morphology of sulfide inclusions, and phosphorus elements affect the brittleness of the casting. Imbalances in the content of these components directly alter the performance of the casting.

[0003] Existing cast iron double-suction impellers largely follow the general cast iron formulation for pump bodies, failing to tailor element composition to the stress characteristics of the symmetrical inlet channels on both sides of the impeller. In scenarios involving frequent start-ups and shutdowns, media containing solid particles, and significant variations in operating conditions, impeller blade roots and hub seals frequently experience crack propagation and overall fracture failure. This leads to a substantial increase in unplanned downtime for maintenance and high impeller replacement costs. Simply thickening the impeller wall for reinforcement directly disrupts the hydraulic model of the double-suction pump, resulting in decreased pump efficiency and increased energy consumption. This approach fails to address the strength issue at its source. Therefore, it is crucial to precisely control the types and contents of cast iron alloy elements and optimize the matrix structure to improve the overall mechanical strength and service life of double-suction pump impellers from a material perspective. Summary of the Invention

[0004] To address the above technical problems, this invention provides an impeller for a double-suction pump and its manufacturing method. The impeller for a double-suction pump provided by this invention has excellent strength, solving the problems of insufficient strength of existing impellers and the lack of research specifically on impellers for double-suction pumps.

[0005] The specific technical solution of the present invention is as follows: According to one aspect of the present invention, an impeller for a double-suction pump is provided, comprising the following components by mass percentage: C: 3.60%~3.72%, Si: 1.85%~2.05%, Mn: 0.35%~0.60%, Mo: 0.22%~0.30%, Cu: 0.75%~0.95%, Ni: 0.45%~0.55%, V: 0.30%~0.42%, Ti: 0.04%~0.08%, B: 0.03%~0.06%, Sn: 0.008%~0.012%, Mg: 0.025%~0.040%, N: 0.015%~0.025%, P≤0.05%, S≤0.03%, with the balance being Fe and unavoidable impurities.

[0006] In the above technical solution, the impeller for the double-suction pump is composed of the following components by mass percentage: C: 3.60%~3.72%, Si: 1.85%~2.05%, Mn: 0.35%~0.60%, Mo: 0.22%~0.30%, Cu: 0.75%~0.95%, Ni: 0.45%~0.55%, V: 0.30%~0.42%, Ti: 0.04%~0.08%, B: 0.03%~0.06%, Sn: 0.008%~0.012%, Mg: 0.025%~0.040%, N: 0.015%~0.025%, P≤0.05%, S≤0.03%, with the balance being Fe and unavoidable impurities; the mass percentages of Mn, Mo, and Mg satisfy the following relationship: 0.18%≤Mn-Mo+Mg≤0.32%.

[0007] In the above technical solution, the impeller for the double-suction pump is composed of the following components by mass percentage: C: 3.60%~3.72%, Si: 1.85%~2.05%, Mn: 0.35%~0.60%, Mo: 0.22%~0.30%, Cu: 0.75%~0.95%, Ni: 0.45%~0.55%, V: 0.30%~0.42%, Ti: 0.04%~0.08%, B: 0. The content of Mn, Mo, and Mg is 0.03%~0.06%, Sn: 0.008%~0.012%, Mg: 0.025%~0.040%, N: 0.015%~0.025%, P≤0.05%, S≤0.03%, with the balance being Fe and unavoidable impurities; when the mass percentages of Mn, Mo, and Mg satisfy the following relationship: Mn-Mo+Mg=0.252%, the mass percentage of Ti is 0.058%.

[0008] According to another aspect of the present invention, the present invention also provides a method for preparing the above-mentioned impeller for a double-suction pump, the steps of which include: A1. Weigh each raw material according to the target composition requirements, add them to the induction furnace to melt and mix them to obtain homogeneous molten iron; A2. The homogeneous molten iron is subjected to spheroidizing treatment, inoculation treatment, casting treatment, and heat treatment to obtain an impeller for a double-suction pump.

[0009] In the above technical solution, a preservative and an external reinforcing phase are added during the incubation process.

[0010] In the above technical solution, the inoculant includes at least one of ferrosilicon inoculant, strontium silicon inoculant, barium silicon inoculant, and calcium silicon inoculant; The added reinforcing phase includes silicon carbide, and the surface of the silicon carbide is provided with a nickel plating layer or a nickel-copper plating layer.

[0011] In the above technical solution, the added reinforcing phase includes silicon carbide, and the surface of the silicon carbide is provided with a nickel-copper plating layer.

[0012] In the above technical solution, the particle size of the silicon carbide is 7μm, and the nickel-copper plating layer on the surface of the silicon carbide contains 38.5wt% nickel and 20wt% copper.

[0013] In the above technical solution, the temperature of the incubation treatment is 1480~1500℃, and the incubation treatment time is 3~8min; The amount of inoculant added is 0.4% to 0.8% of the total mass of molten iron; the amount of the added reinforcing phase added is 0.15% to 0.35% of the total mass of molten iron.

[0014] In the above technical solution, during the heat treatment, the impeller casting is heated to 880~920℃, held for 2~4 hours, then air-cooled, then heated to 620~660℃, held for 3~5 hours, and then slowly cooled in the furnace to below 200℃ before being taken out of the furnace.

[0015] Compared with existing technologies, this invention provides an impeller for a double-suction pump, optimizing the composition of the cast iron used in the impeller. Utilizing the synergistic strengthening effects of elements such as Mn, Mo, Mg, and Ti, the impeller matrix strength is significantly improved, adapting to the complex operating conditions of high-speed fluid impact and alternating loads. Key aspects include: Mn effectively neutralizes the brittleness of sulfur, refines the pearlite matrix structure and dense grain structure, preventing impeller cracking under stress; Mo stabilizes the matrix carbides, refines the pearlite lamellar structure, inhibits softening under high temperature and alternating loads, and improves the uneven mechanical properties of the casting; Mg optimizes graphite morphology and eliminates stress concentration at graphite tips; and Ti combines with nitrogen and carbon to form a dispersed, hard, refined phase, effectively refining the as-cast grains, purifying grain boundaries, reducing grain boundary defects, and inhibiting crack initiation and propagation. The invention features precise proportions and synergistic effects of key elements, while also incorporating auxiliary alloying elements such as Cu, Ni, and V to optimize matrix properties, giving the impeller high strength and ensuring the stability and service life of the dual-suction pump. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention more apparent, the invention is described in detail below. It should be understood that the invention is not limited to the description herein.

[0017] Pregnancy The inoculant used in this invention is a known inoculant in the art for preparing impellers, and this invention is not limited to the types listed below. Those skilled in the art can select other cast iron inoculants with equivalent effects according to actual production conditions, the need for fine-tuning the molten iron composition, and the impeller performance requirements. For example, the inoculant can be at least one of ferrosilicon inoculant, strontium silicon inoculant, barium silicon inoculant, and calcium silicon inoculant. Any single inoculant can be used, or two or more inoculants can be compounded in any proportion. In this invention, for the high-carbon, high-silicon molten iron containing molybdenum, vanadium, titanium, boron, and other alloying elements specifically for the double-suction pump impeller, the inoculant can refine the matrix structure after solidification, improve the metallographic structure of cast iron, avoid defects such as coarse flake graphite, loose grains, and grain boundary inclusions that easily occur during conventional cast iron smelting, and improve the uniformity and density of the casting structure. Meanwhile, the inoculant can eliminate micropores and shrinkage in the molten iron, reduce the negative impact of sulfur and phosphorus impurities on the matrix properties, optimize the fluidity and filling performance of the molten iron, and ensure the structural stability and long-term operational reliability of the impeller under complex working conditions. In this invention, the amount of inoculant added is 0.4% to 0.8% based on the total mass of the molten iron, for example, it can be 0.4%, 0.45%, 0.50%, 0.55%, 0.60%, 0.65%, 0.70%, 0.75%, 0.8%, etc., preferably 0.45% to 0.75%, and more preferably 0.5% to 0.7%.

[0018] Added reinforcement phase This invention innovatively employs silicon carbide with a nickel plating or nickel-copper plating as an external reinforcing phase, improving the impeller's strength and wear resistance; among which, nickel-copper plating silicon carbide is preferred. Conventional high-alloy cast iron relies solely on alloying elements in the formula for strengthening, making it difficult to adapt to the harsh working conditions of high-speed media scouring and alternating load impacts on the impeller, resulting in limited improvement in mechanical properties and insufficient wear resistance. Furthermore, bare silicon carbide has poor wettability with molten iron, easily oxidizing and burning off during smelting, agglomerating and floating, failing to effectively bond with the cast iron matrix, and essentially unable to exert a reinforcing effect. This invention uses silicon carbide with a metal plating on its surface, which can form a protective layer in high-temperature molten iron, preventing fiber oxidation and melting. Simultaneously, the nickel and / or copper metal layer has good metallurgical compatibility with the iron-based melt, significantly improving fiber dispersion, avoiding segregation and agglomeration problems, and allowing silicon carbide to be uniformly distributed within the cast iron matrix. Compared to a single nickel plating layer, the nickel-copper composite plating layer exhibits better density. Copper fills the micropores in the plating layer and refines the grain size, while nickel strengthens the interfacial bonding between the fibers and the cast iron matrix, eliminating interfacial stress concentration. The uniformly distributed silicon carbide effectively disperses impact loads, inhibits the initiation and propagation of matrix cracks, and improves the tensile strength of the impeller. Simultaneously, silicon carbide forms a stable and wear-resistant skeleton within the matrix, resisting erosion and wear from media particles. Furthermore, the nickel and copper elements in the plating layer synergistically work with alloying elements such as vanadium, titanium, and molybdenum in the molten iron to refine the microstructure, optimize carbide distribution, and further enhance the density of the casting. The silicon carbide used in this invention has a particle size of 7 μm. In the nickel-copper plating layer on the surface of the silicon carbide, the nickel content is 38.5 wt% of the mass of silicon carbide and the copper content is 20 wt% of the mass of silicon carbide. The silicon carbide with nickel plating or nickel-copper plating on its surface can be prepared by chemical plating or electroplating processes well known in the art, which are conventional powder metallization treatment methods in the art. The specific plating solution formula, electroplating parameters, etc. can be conventionally adjusted according to the target plating layer mass ratio.

[0019] The amount of the added reinforcing phase in this invention, based on the total mass of molten iron, is 0.15% to 0.35%, for example, it can be 0.15%, 0.18%, 0.20%, 0.22%, 0.25%, 0.28%, 0.30%, 0.32%, 0.35%, etc., preferably 0.18% to 0.32%, and more preferably 0.20% to 0.30%.

[0020] Impeller for double suction pump The impeller for the double-suction pump of the present invention is composed of the components of a double-suction pump impeller, Si, Mn, Mo, Cu, Ni, V, Ti, B, Sn, Mg, N, P, and S, with the balance being Fe and unavoidable impurities.

[0021] In the composition (by mass percentage) of the impeller for a double-suction pump, C: 3.60%~3.72%, preferably 3.63%~3.69%, more preferably 3.66%. High carbon content ensures excellent casting flowability of cast iron, adapts to the complex symmetrical flow channel thin-walled structure of the double-suction impeller, and promotes uniform precipitation of spherical / vermicular graphite. When the carbon content is below 3.60%, graphitization is insufficient, and the casting is prone to white iron structure and increased brittleness. When the carbon content is above 3.72%, the graphite is coarse, cutting through the metal matrix and reducing tensile strength. Si: 1.85%~2.05%, preferably 1.90%~2.00%, more preferably 1.95%. Silicon is a strong graphitizing element, synergistically regulating graphite morphology with carbon and strengthening the ferrite matrix through solid solution; Mn: 0.35%~0.60%; Mo: 0.22%~0.30%; Cu: 0.75%~0.95%, preferably 0.80%~0.90%, more preferably 0.85%, copper disperses and precipitates to strengthen pearlite, ensuring corrosion resistance and fatigue resistance, and also improving the wettability of silicon carbide with the iron matrix; Ni: 0.45%~0.55%, preferably 0.48%~0.52%, more preferably 0.50%, nickel widens the austenite stability range, refines grains, and reduces the tendency of castings to stress crack; V: 0.30%~0.42%, preferably 0.33%~0.39%, more preferably 0.36%, vanadium reacts with carbon and nitrogen to form nanoscale... Vanadium carbonitrides pin grain boundaries and hinder grain growth; Ti: 0.04%~0.08%; B: 0.03%~0.06%, preferably 0.04%~0.05%, more preferably 0.045%, trace amounts of boron enrich the grain boundaries, reduce interfacial energy, promote graphite spheroidization, and inhibit the continuous precipitation of lamellar cementite; Sn: 0.008%~0.012%, preferably 0.009%~0.011%, more preferably 0.010%, trace amounts of tin homogenize the pearlite structure, avoid local ferrite enrichment, and balance the hardness difference at different positions of the impeller hub and blades; Mg: 0.025%~0.040%; N: 0.015%~0.025%, preferably 0.018%~0.022%, more preferably 0.020%. Nitrogen forms dispersed hard precipitates with Ti and V, which assist in grain refinement and enhance matrix strength; P≤0.05%, S≤0.03%.

[0022] Furthermore, the mass percentages of Mn, Mo, and Mg satisfy the following relationship: 0.18% ≤ Mn-Mo+Mg ≤ 0.32%, representing synergistic regulation. When the value is below 0.18%, the combined effects of manganese in fixing sulfur, molybdenum in stabilizing carbides, and magnesium in modifying graphite cannot be superimposed, resulting in insufficient matrix strength. When the value is above 0.32%, casting fluidity decreases, and shrinkage defects increase. The optimal relationship is Mn-Mo+Mg = 0.252%, and when combined with Ti = 0.058%, grain refinement and strength matching are optimal.

[0023] Preparation method of impeller for double-suction pump The present invention also provides a method for preparing the above-mentioned impeller for a double-suction pump, the steps of which include: A1. Weigh each raw material according to the target composition requirements, add them to the induction furnace to melt and mix them to obtain homogeneous molten iron; A2. Homogeneous molten iron is subjected to spheroidizing treatment, inoculation treatment, casting treatment, and heat treatment to obtain an impeller for a double-suction pump.

[0024] In this invention, the inoculation temperature is 1480~1500℃, for example, 1480℃, 1490℃, 1500℃, etc., and the inoculation time is 3~8min, which can be 3min, 4min, 5min, 6min, 7min, 8min, etc.; during heat treatment, the impeller casting after casting is heated to 880~920℃, for example, 880℃, 890℃, 900℃, 910℃, 920℃, etc., held at this temperature for 2~4h, then air-cooled, and then heated to 620~660℃, for example, 620℃, 630℃, 640℃, 650℃, 660℃, etc., held at this temperature for 3~5h, and then slowly cooled in the furnace to below 200℃ before being taken out of the furnace.

[0025] To further illustrate the present invention, the following embodiments will provide a detailed description. All raw materials used in the following embodiments and comparative examples of the present invention are commercially available products.

[0026] Example 1 The preparation method of the impeller for the double suction pump includes the following steps: A1. Raw material smelting: accurately weigh each raw material according to the target composition, put the raw material into the induction furnace for high-temperature melting, stir and mix thoroughly, remove slag and impurities from the molten iron, and obtain homogeneous molten iron with uniform composition and pure texture. A2. Spheroidizing and Inoculation Treatment: Heat the homogeneous molten iron to 1490℃, add rare earth ferrosilicon magnesium spheroidizing agent (model: QRMg8HRE3), the amount of spheroidizing agent added is 1.0% of the total mass of molten iron, spheroidize for 90 seconds, remove the slag after sufficient reaction, adjust the temperature of molten iron to 1480℃, and inoculate for 3 minutes; use ferrosilicon inoculant (FeSi75-A) as inoculation aid, the amount of inoculant added is 0.4% of the total mass of molten iron; A3. Casting and molding: After the inoculation treatment is completed, the molten iron is poured into the impeller mold and naturally cast. After cooling, the impeller blank casting is obtained. A4. Segmented heat treatment: The cast impeller is heated to 880℃ at a heating rate of 80℃ / h, held for 4 hours, and then air-cooled to room temperature; then heated again to 620℃ at a heating rate of 70℃ / h, held for 5 hours, and then slowly cooled in the furnace to below 200℃, and then naturally cooled to room temperature to obtain the impeller for the double-suction pump; wherein, the impeller for the double-suction pump is composed of the following components by mass percentage: C: 3.60%, Si: 1.85%, Mn: 0.35%, Mo: 0.22%, Cu: 0.75%, Ni: 0.45%, V: 0.30%, Ti: 0.04%, B: 0.03%, Sn: 0.008%, Mg: 0.025%, N: 0.015%, P: 0.04%, S: 0.02%, with the balance being Fe and unavoidable impurities.

[0027] Example 2 The preparation method of the impeller for the double suction pump includes the following steps: A1. Raw material smelting: accurately weigh each raw material according to the target composition, put the raw material into the induction furnace for high-temperature melting, stir and mix thoroughly, remove slag and impurities from the molten iron, and obtain homogeneous molten iron with uniform composition and pure texture. A2. Spheroidizing and Inoculation Treatment: Heat the homogeneous molten iron to 1500℃, add rare earth ferrosilicon magnesium spheroidizing agent (model: QRMg8HRE3), the amount of spheroidizing agent added is 1.0% of the total mass of molten iron, spheroidize for 90 seconds, remove the slag after sufficient reaction, adjust the temperature of molten iron to 1490℃, and inoculate for 5 minutes; use ferrosilicon inoculant (FeSi75-A) as inoculation aid, the amount of inoculant added is 0.6% of the total mass of molten iron; A3. Casting and molding: After the inoculation treatment is completed, the molten iron is poured into the impeller mold and naturally cast. After cooling, the impeller blank casting is obtained. A4. Segmented heat treatment: The cast impeller is heated to 900℃ at a heating rate of 80℃ / h, held for 3 hours, and then air-cooled to room temperature; then heated again to 640℃ at a heating rate of 70℃ / h, held for 4 hours, and then slowly cooled in the furnace to below 200℃, and then naturally cooled to room temperature to obtain the impeller for the double-suction pump; wherein, the impeller for the double-suction pump is composed of the following components by mass percentage: C: 3.66%, Si: 1.95%, Mn: 0.48%, Mo: 0.26%, Cu: 0.85%, Ni: 0.50%, V: 0.36%, Ti: 0.07%, B: 0.045%, Sn: 0.010%, Mg: 0.032%, N: 0.020%, P: 0.03%, S: 0.015%, with the balance being Fe and unavoidable impurities.

[0028] Example 3 The preparation method of the impeller for the double suction pump includes the following steps: A1. Raw material smelting: accurately weigh each raw material according to the target composition, put the raw material into the induction furnace for high-temperature melting, stir and mix thoroughly, remove slag and impurities from the molten iron, and obtain homogeneous molten iron with uniform composition and pure texture. A2. Spheroidizing and Inoculation Treatment: Heat the homogeneous molten iron to 1520℃, add rare earth ferrosilicon magnesium spheroidizing agent (model: QRMg8HRE3), the amount of spheroidizing agent added is 1.0% of the total mass of molten iron, spheroidize for 90 seconds, remove the slag after sufficient reaction, adjust the temperature of molten iron to 1500℃, and inoculate for 8 minutes; use ferrosilicon inoculant (FeSi75-A) as inoculation aid, the amount of inoculant added is 0.8% of the total mass of molten iron; A3. Casting and molding: After the inoculation treatment is completed, the molten iron is poured into the impeller mold and naturally cast. After cooling, the impeller blank casting is obtained. A4. Segmented heat treatment: The cast impeller is heated to 920℃ at a heating rate of 80℃ / h, held for 2 hours, and then air-cooled to room temperature; then heated again to 660℃ at a heating rate of 70℃ / h, held for 3 hours, and then slowly cooled in the furnace to below 200℃, and then naturally cooled to room temperature to obtain the impeller for the double-suction pump; wherein, the impeller for the double-suction pump is composed of the following components by mass percentage: C: 3.72%, Si: 2.05%, Mn: 0.60%, Mo: 0.30%, Cu: 0.95%, Ni: 0.55%, V: 0.42%, Ti: 0.08%, B: 0.06%, Sn: 0.012%, Mg: 0.040%, N: 0.025%, P: 0.05%, S: 0.03%, with the balance being Fe and unavoidable impurities.

[0029] Example 4 The preparation method of the impeller for the double suction pump includes the following steps: A1. Raw material smelting: accurately weigh each raw material according to the target composition, put the raw material into the induction furnace for high-temperature melting, stir and mix thoroughly, remove slag and impurities from the molten iron, and obtain homogeneous molten iron with uniform composition and pure texture. A2. Spheroidizing and Inoculation Treatment: Heat the homogeneous molten iron to 1500℃, add rare earth ferrosilicon magnesium spheroidizing agent (model: QRMg8HRE3), the amount of spheroidizing agent added is 1.0% of the total mass of molten iron, spheroidize for 90 seconds, remove the slag after sufficient reaction, adjust the temperature of molten iron to 1480℃, and inoculate for 5 minutes; use ferrosilicon inoculant (FeSi75-A) as inoculation aid, the amount of inoculant added is 0.6% of the total mass of molten iron; A3. Casting and molding: After the inoculation treatment is completed, the molten iron is poured into the impeller mold and naturally cast. After cooling, the impeller blank casting is obtained. A4. Segmented heat treatment: The cast impeller is heated to 900℃ at a heating rate of 80℃ / h, held for 3 hours, and then air-cooled to room temperature; then heated again to 640℃ at a heating rate of 70℃ / h, held for 4 hours, and then slowly cooled in the furnace to below 200℃, and then naturally cooled to room temperature to obtain the impeller for the double-suction pump; wherein, the impeller for the double-suction pump is composed of the following components by mass percentage: C: 3.66%, Si: 1.95%, Mn: 0.60%, Mo: 0.30%, Cu: 0.85%, Ni: 0.50%, V: 0.36%, Ti: 0.07%, B: 0.045%, Sn: 0.010%, Mg: 0.040%, N: 0.020%, P: 0.03%, S: 0.015%, with the balance being Fe and unavoidable impurities.

[0030] Example 5 The preparation method of the impeller for the double suction pump includes the following steps: A1. Raw material smelting: accurately weigh each raw material according to the target composition, put the raw material into the induction furnace for high-temperature melting, stir and mix thoroughly, remove slag and impurities from the molten iron, and obtain homogeneous molten iron with uniform composition and pure texture. A2. Spheroidizing and Inoculation Treatment: Heat the homogeneous molten iron to 1500℃, add rare earth ferrosilicon magnesium spheroidizing agent (model: QRMg8HRE3), the amount of spheroidizing agent added is 1.0% of the total mass of molten iron, spheroidize for 90 seconds, remove the slag after sufficient reaction, adjust the temperature of molten iron to 1480℃, and inoculate for 5 minutes; use ferrosilicon inoculant (FeSi75-A) as inoculation aid, the amount of inoculant added is 0.6% of the total mass of molten iron; A3. Casting and molding: After the inoculation treatment is completed, the molten iron is poured into the impeller mold and naturally cast. After cooling, the impeller blank casting is obtained. A4. Segmented heat treatment: The cast impeller is heated to 900℃ at a heating rate of 80℃ / h, held for 3 hours, and then air-cooled to room temperature; then heated again to 640℃ at a heating rate of 70℃ / h, held for 4 hours, and then slowly cooled in the furnace to below 200℃, and then naturally cooled to room temperature to obtain the impeller for the double-suction pump; wherein, the impeller for the double-suction pump is composed of the following components by mass percentage: C: 3.66%, Si: 1.95%, Mn: 0.35%, Mo: 0.22%, Cu: 0.85%, Ni: 0.50%, V: 0.36%, Ti: 0.07%, B: 0.045%, Sn: 0.010%, Mg: 0.025%, N: 0.020%, P: 0.03%, S: 0.015%, with the balance being Fe and unavoidable impurities.

[0031] Example 6 The preparation method of the impeller for the double suction pump includes the following steps: A1. Raw material smelting: accurately weigh each raw material according to the target composition, put the raw material into the induction furnace for high-temperature melting, stir and mix thoroughly, remove slag and impurities from the molten iron, and obtain homogeneous molten iron with uniform composition and pure texture. A2. Spheroidizing and Inoculation Treatment: Heat the homogeneous molten iron to 1500℃, add rare earth ferrosilicon magnesium spheroidizing agent (model: QRMg8HRE3), the amount of spheroidizing agent added is 1.0% of the total mass of molten iron, spheroidize for 90 seconds, remove the slag after sufficient reaction, adjust the temperature of molten iron to 1480℃, and inoculate for 5 minutes; use ferrosilicon inoculant (FeSi75-A) as inoculation aid, the amount of inoculant added is 0.6% of the total mass of molten iron; A3. Casting and molding: After the inoculation treatment is completed, the molten iron is poured into the impeller mold and naturally cast. After cooling, the impeller blank casting is obtained. A4. Segmented heat treatment: The cast impeller is heated to 900℃ at a heating rate of 80℃ / h, held for 3 hours, and then air-cooled to room temperature; then heated again to 640℃ at a heating rate of 70℃ / h, held for 4 hours, and then slowly cooled in the furnace to below 200℃, and then naturally cooled to room temperature to obtain the impeller for the double-suction pump; wherein, the impeller for the double-suction pump is composed of the following components by mass percentage: C: 3.66%, Si: 1.95%, Mn: 0.38%, Mo: 0.24%, Cu: 0.85%, Ni: 0.50%, V: 0.36%, Ti: 0.07%, B: 0.045%, Sn: 0.010%, Mg: 0.040%, N: 0.020%, P: 0.03%, S: 0.015%, with the balance being Fe and unavoidable impurities.

[0032] Example 7 The preparation method of the impeller for the double suction pump includes the following steps: A1. Raw material smelting: accurately weigh each raw material according to the target composition, put the raw material into the induction furnace for high-temperature melting, stir and mix thoroughly, remove slag and impurities from the molten iron, and obtain homogeneous molten iron with uniform composition and pure texture. A2. Spheroidizing and Inoculation Treatment: Heat the homogeneous molten iron to 1500℃, add rare earth ferrosilicon magnesium spheroidizing agent (model: QRMg8HRE3), the amount of spheroidizing agent added is 1.0% of the total mass of molten iron, spheroidize for 90 seconds, remove the slag after sufficient reaction, adjust the temperature of molten iron to 1480℃, and inoculate for 5 minutes; use ferrosilicon inoculant (FeSi75-A) as inoculation aid, the amount of inoculant added is 0.6% of the total mass of molten iron; A3. Casting and molding: After the inoculation treatment is completed, the molten iron is poured into the impeller mold and naturally cast. After cooling, the impeller blank casting is obtained. A4. Segmented heat treatment: The cast impeller is heated to 900℃ at a heating rate of 80℃ / h, held for 3 hours, and then air-cooled to room temperature; then heated again to 640℃ at a heating rate of 70℃ / h, held for 4 hours, and then slowly cooled in the furnace to below 200℃, and then naturally cooled to room temperature to obtain the impeller for the double-suction pump; wherein, the impeller for the double-suction pump is composed of the following components by mass percentage: C: 3.66%, Si: 1.95%, Mn: 0.58%, Mo: 0.30%, Cu: 0.85%, Ni: 0.50%, V: 0.36%, Ti: 0.07%, B: 0.045%, Sn: 0.010%, Mg: 0.04%, N: 0.020%, P: 0.03%, S: 0.015%, with the balance being Fe and unavoidable impurities.

[0033] Example 8 The preparation method of the impeller for the double suction pump includes the following steps: A1. Raw material smelting: accurately weigh each raw material according to the target composition, put the raw material into the induction furnace for high-temperature melting, stir and mix thoroughly, remove slag and impurities from the molten iron, and obtain homogeneous molten iron with uniform composition and pure texture. A2. Spheroidizing and Inoculation Treatment: Heat the homogeneous molten iron to 1500℃, add rare earth ferrosilicon magnesium spheroidizing agent (model: QRMg8HRE3), the amount of spheroidizing agent added is 1.0% of the total mass of molten iron, spheroidize for 90 seconds, remove the slag after sufficient reaction, adjust the temperature of molten iron to 1480℃, and inoculate for 5 minutes; use ferrosilicon inoculant (FeSi75-A) as inoculation aid, the amount of inoculant added is 0.6% of the total mass of molten iron; A3. Casting and molding: After the inoculation treatment is completed, the molten iron is poured into the impeller mold and naturally cast. After cooling, the impeller blank casting is obtained. A4. Segmented heat treatment: The cast impeller is heated to 900℃ at a heating rate of 80℃ / h, held for 3 hours, and then air-cooled to room temperature; then heated again to 640℃ at a heating rate of 70℃ / h, held for 4 hours, and then slowly cooled in the furnace to below 200℃, and then naturally cooled to room temperature to obtain the impeller for the double-suction pump; wherein, the impeller for the double-suction pump is composed of the following components by mass percentage: C: 3.66%, Si: 1.95%, Mn: 0.48%, Mo: 0.26%, Cu: 0.85%, Ni: 0.50%, V: 0.36%, Ti: 0.058%, B: 0.045%, Sn: 0.010%, Mg: 0.032%, N: 0.020%, P: 0.03%, S: 0.015%, with the balance being Fe and unavoidable impurities.

[0034] Example 9 The preparation method of the impeller for the double suction pump includes the following steps: A1. Raw material smelting: accurately weigh each raw material according to the target composition, put the raw material into the induction furnace for high-temperature melting, stir and mix thoroughly, remove slag and impurities from the molten iron, and obtain homogeneous molten iron with uniform composition and pure texture. A2. Spheroidizing and Inoculation Treatment: Heat the homogeneous molten iron to 1500℃, add rare earth ferrosilicon magnesium spheroidizing agent (model: QRMg8HRE3), the amount of spheroidizing agent added is 1.0% of the total mass of molten iron, spheroidize for 90 seconds, remove the slag after sufficient reaction, adjust the temperature of molten iron to 1480℃, and inoculate for 5 minutes; use ferrosilicon inoculant (FeSi75-A) as inoculation aid, the amount of inoculant added is 0.6% of the total mass of molten iron; A3. Casting and molding: After the inoculation treatment is completed, the molten iron is poured into the impeller mold and naturally cast. After cooling, the impeller blank casting is obtained. A4. Segmented heat treatment: The cast impeller is heated to 900℃ at a heating rate of 80℃ / h, held for 3 hours, and then air-cooled to room temperature; then heated again to 640℃ at a heating rate of 70℃ / h, held for 4 hours, and then slowly cooled in the furnace to below 200℃, and then naturally cooled to room temperature to obtain the impeller for the double-suction pump; wherein, the impeller for the double-suction pump is composed of the following components by mass percentage: C: 3.66%, Si: 1.95%, Mn: 0.48%, Mo: 0.26%, Cu: 0.85%, Ni: 0.50%, V: 0.36%, Ti: 0.042%, B: 0.045%, Sn: 0.010%, Mg: 0.032%, N: 0.020%, P: 0.03%, S: 0.015%, with the balance being Fe and unavoidable impurities.

[0035] Example 10 The preparation method of the impeller for the double suction pump includes the following steps: A1. Raw material smelting: accurately weigh each raw material according to the target composition, put the raw material into the induction furnace for high-temperature melting, stir and mix thoroughly, remove slag and impurities from the molten iron, and obtain homogeneous molten iron with uniform composition and pure texture. A2. Spheroidizing and Inoculation Treatment: Heat the homogeneous molten iron to 1500℃, add rare earth ferrosilicon magnesium spheroidizing agent (model: QRMg8HRE3), the amount of spheroidizing agent added is 1.0% of the total mass of molten iron, spheroidize for 90s, after sufficient reaction, remove the slag, adjust the temperature of molten iron to 1480℃, and inoculate for 5min; use ferrosilicon inoculator (FeSi75-A) as inoculation aid, the amount of inoculator added is 0.6% of the total mass of molten iron, and add an external reinforcing phase, the amount of which is 0.25% of the total mass of molten iron; The added reinforcing phase is silicon carbide with a nickel-copper coating, and the silicon carbide particle size is 7 μm; in the nickel-copper coating, the nickel content is 38.5 wt% of the silicon carbide mass, and the copper content is 20 wt% of the silicon carbide mass. A3. Casting and molding: After the inoculation treatment is completed, the molten iron is poured into the impeller mold and naturally cast. After cooling, the impeller blank casting is obtained. A4. Segmented heat treatment: The cast impeller is heated to 900℃ at a heating rate of 80℃ / h, held for 3 hours, and then air-cooled to room temperature; then heated again to 640℃ at a heating rate of 70℃ / h, held for 4 hours, and then slowly cooled in the furnace to below 200℃, and then naturally cooled to room temperature to obtain the impeller for the double-suction pump; wherein, the impeller for the double-suction pump is composed of the following components by mass percentage: C: 3.66%, Si: 1.95%, Mn: 0.48%, Mo: 0.26%, Cu: 0.85%, Ni: 0.50%, V: 0.36%, Ti: 0.058%, B: 0.045%, Sn: 0.010%, Mg: 0.032%, N: 0.020%, P: 0.03%, S: 0.015%, with the balance being Fe and unavoidable impurities.

[0036] Example 11 The preparation method of the impeller for the double suction pump includes the following steps: A1. Raw material smelting: accurately weigh each raw material according to the target composition, put the raw material into the induction furnace for high-temperature melting, stir and mix thoroughly, remove slag and impurities from the molten iron, and obtain homogeneous molten iron with uniform composition and pure texture. A2. Spheroidizing and Inoculation Treatment: Heat the homogeneous molten iron to 1500℃, add rare earth ferrosilicon magnesium spheroidizing agent (model: QRMg8HRE3), the amount of spheroidizing agent added is 1.0% of the total mass of molten iron, spheroidize for 90s, after sufficient reaction, remove the slag, adjust the temperature of molten iron to 1480℃, and inoculate for 5min; use ferrosilicon inoculator (FeSi75-A) as inoculation aid, the amount of inoculator added is 0.6% of the total mass of molten iron, and add an external reinforcing phase, the amount of which is 0.25% of the total mass of molten iron; The added reinforcing phase is silicon carbide with a nickel plating layer on the surface, and the particle size of the silicon carbide is 7 μm; the mass of the nickel plating layer is 60 wt% of the mass of the silicon carbide. A3. Casting and molding: After the inoculation treatment is completed, the molten iron is poured into the impeller mold and naturally cast. After cooling, the impeller blank casting is obtained. A4. Segmented heat treatment: The cast impeller is heated to 900℃ at a heating rate of 80℃ / h, held for 3 hours, and then air-cooled to room temperature; then heated again to 640℃ at a heating rate of 70℃ / h, held for 4 hours, and then slowly cooled in the furnace to below 200℃, and then naturally cooled to room temperature to obtain the impeller for the double-suction pump; wherein, the impeller for the double-suction pump is composed of the following components by mass percentage: C: 3.66%, Si: 1.95%, Mn: 0.48%, Mo: 0.26%, Cu: 0.85%, Ni: 0.50%, V: 0.36%, Ti: 0.058%, B: 0.045%, Sn: 0.010%, Mg: 0.032%, N: 0.020%, P: 0.03%, S: 0.015%, with the balance being Fe and unavoidable impurities.

[0037] The impellers prepared in Examples 1 to 11 were subjected to the following performance tests. The tensile strength was tested according to the standard GB / T 9439-2023, and the results are shown in Table 1 below.

[0038] Table 1 Tensile strength test

[0039] The tensile strength of the double-suction pump impeller prepared in the embodiments of the present invention is stably in the range of 380~462MPa, and its overall mechanical strength performance is significantly better than that of conventional cast iron impellers. Among them, the tensile strength of Examples 4-5 is lower than that of Examples 2 and Examples 6-7 because the synergistic control relationship of 0.18%≤Mn-Mo+Mg≤0.32% is not satisfied; Example 8 satisfies Mn-Mo+Mg=0.252% and Ti mass percentage 0.058%, and the tensile strength reaches 439MPa; Examples 10 and 11 further improve the tensile strength by introducing silicon carbide external reinforcing phase with surface coating during the inoculation treatment.

[0040] Friction and wear tests were conducted using a friction and wear testing machine at a test temperature of 500℃. The mating part was a φ6mm GCr15 steel ball, the normal load was 15N, and the rotation speed was 600r / min. The results are shown in Table 2 below (the results are the average of three parallel tests).

[0041] Table 2 Abrasion resistance test

[0042] In Example 8, the wear volume was reduced compared to Example 2 by optimizing the composition ratio of Mn, Mo, Mg and Ti; in Examples 10 and 11, the wear volume was further reduced by introducing silicon carbide as an external reinforcing phase in the coating.

[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An impeller for a double-suction pump, characterized in that, It is composed of the following components by mass percentage: C: 3.60%~3.72%, Si: 1.85%~2.05%, Mn: 0.35%~0.60%, Mo: 0.22%~0.30%, Cu: 0.75%~0.95%, Ni: 0.45%~0.55%, V: 0.30%~0.42%, Ti: 0.04%~0.08%, B: 0.03%~0.06%, Sn: 0.008%~0.012%, Mg: 0.025%~0.040%, N: 0.015%~0.025%, P≤0.05%, S≤0.03%, with the balance being Fe and unavoidable impurities.

2. The impeller for a double-suction pump according to claim 1, characterized in that, Composed of the following components by mass percentage Composition: C: 3.60%~3.72%, Si: 1.85%~2.05%, Mn: 0.35%~0.60%, Mo: 0.22%~0.30%, Cu: 0.75%~0.95%, Ni: 0.45%~0.55%, V: 0.30%~0.42%, Ti: 0.04%~0.08%, B: 0.03%~0.06%, Sn: 0.008%~0.012%, Mg: 0.025%~0.040%, N: 0.015%~0.025%, P≤0.05%, S≤0.03%, with the balance being Fe and unavoidable impurities; the mass percentages of Mn, Mo, and Mg satisfy the following relationship: 0.18%≤Mn-Mo+Mg≤0.32%.

3. The impeller for a double-suction pump according to claim 2, characterized in that, Composed of the following components by mass percentage Composition: C: 3.60%~3.72%, Si: 1.85%~2.05%, Mn: 0.35%~0.60%, Mo: 0.22%~0.30%, Cu: 0.75%~0.95%, Ni: 0.45%~0.55%, V: 0.30%~0.42%, Ti: 0.04%~0.08%, B: 0.03%~0.06%, Sn: 0.008%~0.012%, Mg: 0.025%~0.040%, N: 0.015%~0.025%, P≤0.05%, S≤0.03%, with the balance being Fe and unavoidable impurities; when the mass percentages of Mn, Mo, and Mg satisfy the following relationship: Mn-Mo+Mg=0.252%, the mass percentage of Ti is 0.058%.

4. A method for preparing an impeller for a double-suction pump, used to prepare the impeller for a double-suction pump according to any one of claims 1 to 3, characterized in that the step... include: A1. Weigh each raw material according to the target composition requirements, add them to the induction furnace to melt and mix them to obtain homogeneous molten iron; A2. The homogeneous molten iron is subjected to spheroidizing treatment, inoculation treatment, casting treatment, and heat treatment to obtain an impeller for a double-suction pump.

5. The method for preparing an impeller for a double-suction pump according to claim 4, characterized in that, The incubation process involves the addition of a preservative and an external reinforcing phase.

6. The method for preparing an impeller for a double-suction pump according to claim 5, characterized in that, The inoculant includes at least one of ferrosilicon inoculant, strontium silicon inoculant, barium silicon inoculant, and calcium silicon inoculant; The added reinforcing phase includes silicon carbide, and the surface of the silicon carbide is provided with a nickel plating layer or a nickel-copper plating layer.

7. The method for preparing an impeller for a double-suction pump according to claim 6, characterized in that, The added reinforcing phase includes silicon carbide, and the surface of the silicon carbide is provided with a nickel-copper plating layer.

8. The method for preparing an impeller for a double-suction pump according to claim 7, characterized in that, The silicon carbide has a particle size of 7 μm, and the nickel-copper plating on the surface of the silicon carbide contains 38.5 wt% nickel and 20 wt% copper.

9. The method for preparing an impeller for a double-suction pump according to claim 5, characterized in that, The incubation treatment temperature is 1480~1500℃, and the incubation treatment time is 3~8 minutes; The amount of inoculant added is 0.4% to 0.8% of the total mass of molten iron; the amount of the added reinforcing phase added is 0.15% to 0.35% of the total mass of molten iron.

10. A method for preparing an impeller for a double-suction pump according to claim 4, characterized in that, During the heat treatment, the impeller casting is heated to 880~920℃, held for 2~4 hours, then air-cooled, then heated to 620~660℃, held for 3~5 hours, and then slowly cooled in the furnace to below 200℃ before being taken out of the furnace.

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