Low-temperature-impact-resistant wind power nodular cast iron material and preparation method thereof
By introducing nickel and molybdenum elements during the smelting process, and combining antimony elements in the spheroidization inoculation stage with ultrasonic treatment, the problem of brittle fracture of traditional ductile iron in low-temperature environment was solved, and wind power ductile iron material with both high strength and excellent low-temperature impact performance was prepared.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-01
- Publication Date
- 2026-03-13
AI Technical Summary
Traditional ductile iron is prone to brittle fracture in low-temperature environments, making it difficult to meet the safety and reliability requirements of wind power equipment at temperatures below -20°C or even -40°C. Existing improvement methods are insufficient to balance high strength, high toughness, and excellent low-temperature impact resistance.
By introducing nickel and molybdenum elements during the smelting process, combined with antimony elements during the spheroidization inoculation stage and ultrasonic treatment during casting, a low-temperature impact-resistant ductile iron material for wind power was prepared. This ensures that the alloying elements are uniformly dissolved and the microstructure is refined, while inhibiting the precipitation of brittle phases.
The prepared low-temperature impact resistant ductile iron material for wind power not only meets the high strength requirements of QT400-18AL, but also significantly improves the low-temperature impact performance and enhances the toughness and reliability of the material under extreme climate conditions.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention relates to the field of casting technology, specifically to a low-temperature impact resistant ductile iron material for wind power and its preparation method. Background Technology
[0002] With the continuous growth of global demand for renewable energy, wind power, as an important component of clean energy, has seen its installed capacity expand steadily. Wind turbines are typically deployed in extreme climate environments such as high latitudes, high altitudes, or offshore, and are exposed to harsh conditions such as low temperatures, strong winds, high humidity, and alternating loads for extended periods, placing extremely stringent performance requirements on key structural materials. Ductile iron, due to its excellent casting properties, high strength, and certain toughness, is widely used in core components such as wind turbine gearbox housings, hubs, and bases. However, traditional ductile iron is prone to brittle fracture at low temperatures, and its impact toughness decreases significantly, making it difficult to meet the safety and reliability requirements of wind power equipment operating at temperatures as low as -20°C or even -40°C.
[0003] Currently, while the mechanical properties of ordinary ductile iron can be improved to some extent by adjusting the carbon equivalent, adding alloying elements, or optimizing the heat treatment process, achieving excellent low-temperature impact resistance while maintaining high strength and high toughness remains a significant challenge. Therefore, there is an urgent need to develop a wind power ductile iron material that combines high strength, high toughness, and excellent low-temperature impact toughness. Summary of the Invention
[0004] The purpose of this invention is to provide a low-temperature impact resistant ductile iron material for wind power and its preparation method, so as to solve the technical problems mentioned in the background art.
[0005] The technical solution to achieve the objective of this invention is: In a first aspect, the present invention provides a method for preparing a low-temperature impact-resistant ductile iron material for wind power, the preparation steps including: A1. Material preparation; A2. Add scrap steel, carbon raiser, molybdenum wire, pig iron, recycled material, and pure nickel plate into the medium frequency furnace in sequence. After all the furnace materials have melted, let them stand and remove slag. A3. Add the spheroidizing agent, inoculant, metallic antimony, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A2 into the ladle for spheroidizing and inoculation; A4. After removing the slag from the molten iron obtained in step A3, pour it into the mold and perform ultrasonic treatment. Add a flow-inducing agent during the pouring process. A5. After pouring, slowly cool the casting in the sand mold to below 400°C and remove it from the mold.
[0006] Furthermore, the materials prepared in the material preparation step include, by weight percentage: 40-60 wt% pig iron, 20-30 wt% recycled material, 10-20 wt% scrap steel, 0.3-0.5 wt% molybdenum wire, and 0.2-0.6 wt% pure nickel.
[0007] Furthermore, the elements and contents of the casting composition include: 3.8wt%C, 1.94~1.97wt%Si, 0.131~0.139wt%Mn, 0.022wt%P, 0.007wt%S, 0.038~0.039wt%Mg, 0.006~0.007wt%Re, 0.0028~0.0053wt%Sb, 0.30~0.50wt%Ni, 0.1~0.3wt%Mo, and the remainder is iron.
[0008] Furthermore, the inoculant is a silicon-calcium-barium inoculant, whose main components include 60-80% Si, 1.5-5% Ba, and 0.2-1.0% Ca; the amount of the inoculant added is 0.3-0.5 wt% based on the weight percentage of the molten iron.
[0009] Furthermore, the amount of the covering agent added is 0.2~0.3 wt% based on the weight percentage of the molten iron.
[0010] Furthermore, the amount of antimony metal added is 0.003~0.006 wt% based on the weight percentage of the molten iron.
[0011] Furthermore, the in-flow inoculant is a sulfur-oxygen inoculant, whose main components include 68~80wt%Si, 0.5~1.5wt%Ca, and 0.5~1.5wt%Al; the amount of in-flow inoculant added is 0.1~0.2wt% based on the weight percentage of the molten iron.
[0012] Furthermore, the ultrasonic intensity of the ultrasonic treatment is 400~600W, and the ultrasonic duration is 20~30s.
[0013] Furthermore, polyurethane foam sand is added to the molding sand.
[0014] In a second aspect, the present invention provides a low-temperature impact resistant ductile iron material for wind power, which is prepared according to the preparation method of the low-temperature impact resistant ductile iron material for wind power described in the first aspect.
[0015] By adopting the above technical solution, the present invention has the following beneficial effects: In the preparation of the low-temperature impact resistant ductile iron material for wind power of the present invention, the following steps are taken: First, prepare the raw materials; then, add the prepared scrap steel, carbon raiser, molybdenum wire, pig iron, recycled material, and pure nickel plate into the medium-frequency furnace in sequence. After all the furnace materials have melted, let them stand and remove slag; then, add the spheroidizing agent, inoculant, metallic antimony, and covering agent to the bottom of the ladle in sequence, and then pour the mixture into the ladle for spheroidization and inoculation; next, after removing the slag from the molten iron, pour it into the mold and perform ultrasonic treatment, adding an inoculant during the pouring process; finally, after pouring, slowly cool the mixture in the sand mold to below 400°C and remove the casting from the mold. The resulting low-temperature impact resistant ductile iron material for wind power meets the high strength requirements of QT400-18AL while significantly improving low-temperature impact performance.
[0016] First, scrap steel, carbon raiser, molybdenum wire, pig iron, recycled material, and pure nickel plate are sequentially added to the medium-frequency furnace to ensure uniform dissolution of alloying elements and precise control of carbon equivalent and the content of each component element. Nickel, as an austenite stabilizing element, effectively promotes the formation of ferrite matrix and solid solution strengthening, significantly improving the impact toughness of the material in low-temperature environments such as -40℃. At the same time, nickel's non-carbide formation characteristic helps to avoid the precipitation of brittle phases and ensures the uniformity of the microstructure. Molybdenum plays a role in refining pearlite, inhibiting the coarsening of eutectoid transformation, and improving the hardenability and microstructure consistency of the casting cross section, effectively maintaining the strength of ductile iron. After melting and cleaning, the furnace is allowed to stand for slag removal, which helps to reduce the content of inclusions and reduce stress concentration sources.
[0017] Subsequently, the spheroidizing agent, inoculant, metallic antimony, and covering agent are added sequentially to the bottom of the ladle, which is then poured into the ladle for spheroidization and inoculation. Antimony, as a surface-active element, can effectively inhibit the distortion and fragmentation of graphite during solidification, promote the rounding of graphite spheres, and improve the spheroidization rate. At the same time, antimony can also refine the size of eutectic clusters and reduce grain boundary segregation, thereby improving the uniformity of the matrix structure. In addition, an appropriate amount of antimony can suppress the adverse effects of anti-spheroidizing elements (such as Ti and As), stabilize the spheroidization effect, avoid low-temperature brittleness caused by graphite morphology deterioration, and further improve the low-temperature impact resistance of ductile iron.
[0018] Next, after slag removal, the molten iron is poured into the mold and subjected to ultrasonic treatment. Ultrasonic treatment breaks up primary dendrites and promotes compositional homogenization through cavitation and acoustic flow effects, further refining eutectic clusters and graphite spheres, thereby improving the density and uniformity of the microstructure. During the pouring process, an inoculant is added. The inoculant provides additional nucleation sites the instant the molten iron flows into the mold cavity, effectively refining the size of eutectic clusters and graphite spheres, inhibiting graphite floating and segregation, thereby improving the uniformity of the microstructure. Finally, after pouring, the casting is slowly cooled to below 400°C in the sand mold and removed from the mold to avoid excessive internal stress or brittle phase precipitation caused by rapid cooling. This invention introduces nickel and molybdenum elements during the smelting process, antimony elements during the spheroidizing inoculation stage, and combines this with the ultrasonic treatment process during casting to produce a low-temperature impact resistant ductile iron material for wind power that meets the high strength requirements of QT400-18AL while also possessing excellent low-temperature impact resistance. Detailed Implementation
[0019] To better understand the above technical solution, the following will provide a detailed explanation of the technical solution in conjunction with specific implementation methods.
[0020] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.
[0021] The following embodiments are only used to illustrate the technical solutions of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.
[0022] Low-silicon pig iron is used, and the content of Si in low-silicon pig iron is 0.5~1.0wt%, Mn≤0.5wt%, P≤0.06wt%, S≤0.03wt%, and harmful alloying elements≤0.025wt%.
[0023] The scrap steel selected is thin-sheet carbon scrap steel, in which Si≤1.0wt%, Mn≤0.5wt%, P≤0.035wt%, S≤0.03wt%, and Cr≤0.1wt%.
[0024] The recycled material is ferritic ductile iron recycled material.
[0025] The covering agent uses rust-free iron filings with a particle size of 1~2mm.
[0026] The size of the pure nickel plate is 2±0.5mm.
[0027] The spheroidizing agent is a rare earth silicon-iron-magnesium alloy, whose main components include 5.5~6.0wt%Mg, 0.15~0.30wt%Re, 45.0~50.0wt%Si, 0.80~1.50wt%Ca, and the remainder is iron, with a particle size of 4~28 mm.
[0028] The carbon raiser is a high-temperature graphitized carbon raiser with fixed carbon ≥ 99.0% and a particle size of 0.5~5.0 mm.
[0029] The in-flow inoculant is a sulfur-oxygen inoculant, whose main components include 68~80wt% Si, 0.5~1.5wt% Ca, and 0.5~1.5wt% Al; Example
[0030] A method for preparing a low-temperature impact-resistant ductile iron material for wind power, comprising the following steps: A1. Add scrap steel, carbon raiser, molybdenum wire, pig iron, recycled material, and pure nickel plate into the medium frequency furnace in sequence. After all the furnace materials have melted, sprinkle slag remover to remove slag from the molten iron. When the smelting temperature reaches 1500~1530℃, allow it to stand at high temperature and remove slag. When the molten iron temperature reaches 1400~1450℃, it is ready to be taken out of the furnace and spheroidized. A2. Add the spheroidizing agent, inoculant, metallic antimony, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A2 into the ladle for spheroidizing and inoculation; A3. After removing the slag from the molten iron obtained in step A2 at 1350~1370℃, pour it into a mold containing 30% polyurethane foamed sand and perform ultrasonic treatment. Add a flow-inducing agent during the pouring process. A4. After pouring, slowly cool the casting in the sand mold to below 400°C and remove it from the mold.
[0031] The amount of spheroidizing agent added is 0.9~1.2 wt% of the weight of the molten iron.
[0032] The amount of inoculant added is 0.3~0.5 wt% of the weight of the molten iron.
[0033] The amount of covering agent added is 0.2~0.3 wt% of the weight of the molten iron.
[0034] The amount of metallic antimony added is 0.003~0.006 wt% based on the weight percentage of the molten iron.
[0035] The amount of inoculant added is 0.1~0.2wt% based on the weight percentage of the molten iron.
[0036] The ultrasonic intensity of the ultrasonic treatment is 400~600W, and the ultrasonic duration is 20~30s.
[0037] The elements and contents of the casting composition include: 3.8wt%C, 1.94~1.97wt%Si, 0.131~0.139wt%Mn, 0.022wt%P, 0.007wt%S, 0.038~0.039wt%Mg, 0.006~0.007wt%Re, 0.0028~0.0053wt%Sb, 0.30~0.50wt%Ni, 0.1~0.3wt%Mo, and the remainder is iron.
[0038] Example 1 A method for preparing a low-temperature impact-resistant ductile iron material for wind power, comprising the following steps: A1. Add scrap steel, carbon raiser, molybdenum wire, pig iron, recycled material, and pure nickel plate into the medium frequency furnace in sequence. After all the furnace materials have melted, sprinkle slag remover to remove slag from the molten iron. When the smelting temperature reaches 1500℃, allow it to stand at high temperature and remove slag. When the molten iron temperature reaches 1400℃, it is ready to be taken out of the furnace and spheroidized. A2. Add the spheroidizing agent, inoculant, metallic antimony, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A2 into the ladle for spheroidizing and inoculation; A3. After removing the slag from the molten iron obtained in step A2 at 1350℃, pour it into a mold containing 30% polyurethane foamed sand and perform ultrasonic treatment. Add a flow-inducing agent during the pouring process. A4. After pouring, slowly cool the casting in the sand mold to below 400°C and remove it from the mold.
[0039] The amount of spheroidizing agent added is 0.9 wt% based on the weight percentage of the molten iron.
[0040] The amount of inoculant added is 0.3 wt% of the weight of the molten iron.
[0041] The amount of covering agent added is 0.2 wt% of the weight of the molten iron.
[0042] The amount of antimony metal added is 0.003 wt% based on the weight percentage of the molten iron.
[0043] The amount of inoculant added is 0.1 wt% based on the weight percentage of the molten iron.
[0044] The ultrasonic intensity of the ultrasonic treatment was 400W, and the ultrasonic duration was 30s.
[0045] The elements and contents of the casting composition include: 3.8wt%C, 1.94wt%Si, 0.131wt%Mn, 0.022wt%P, 0.007wt%S, 0.039wt%Mg, 0.006wt%Re, 0.0028wt%Sb, 0.31wt%Ni, 0.1wt%Mo, and the remainder is iron.
[0046] Example 2 A method for preparing a low-temperature impact-resistant ductile iron material for wind power, comprising the following steps: A1. Add scrap steel, carbon raiser, molybdenum wire, pig iron, recycled material and pure nickel plate into the medium frequency furnace in sequence. After all the furnace materials have melted, sprinkle slag remover to remove slag from the molten iron. When the smelting temperature reaches 1520℃, allow it to stand at high temperature and remove slag. When the molten iron temperature reaches 1430℃, it is ready to be taken out of the furnace and spheroidized. A2. Add the spheroidizing agent, inoculant, metallic antimony, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A2 into the ladle for spheroidizing and inoculation; A3. After removing the slag from the molten iron obtained in step A2 at 1360℃, pour it into a mold containing 30% polyurethane foamed sand and perform ultrasonic treatment. Add a flow-inducing agent during the pouring process. A4. After pouring, slowly cool the casting in the sand mold to below 400°C and remove it from the mold.
[0047] The amount of spheroidizing agent added is 1 wt% of the weight percentage of the molten iron.
[0048] The amount of inoculant added is 0.4 wt% of the weight of the molten iron.
[0049] The amount of covering agent added is 0.2 wt% of the weight of the molten iron.
[0050] The amount of antimony metal added is 0.005 wt% based on the weight percentage of the molten iron.
[0051] The amount of inoculant added is 0.15 wt% based on the weight percentage of the molten iron.
[0052] The ultrasonic intensity of the ultrasonic treatment was 600W, and the ultrasonic duration was 30s.
[0053] The elements and contents of the casting composition include: 3.8wt%C, 1.97wt%Si, 0.139wt%Mn, 0.022wt%P, 0.007wt%S, 0.038wt%Mg, 0.006wt%Re, 0.0044wt%Sb, 0.42wt%Ni, 0.18wt%Mo, and the remainder is iron.
[0054] Example 3 A method for preparing a low-temperature impact-resistant ductile iron material for wind power, comprising the following steps: A1. Add scrap steel, carbon raiser, molybdenum wire, pig iron, recycled material and pure nickel plate into the medium frequency furnace in sequence. After all the furnace materials have melted, sprinkle slag remover to remove slag from the molten iron. When the smelting temperature reaches 1530℃, allow it to stand at high temperature and remove slag. When the molten iron temperature reaches 1450℃, it is ready to be taken out of the furnace and spheroidized. A2. Add the spheroidizing agent, inoculant, metallic antimony, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A2 into the ladle for spheroidizing and inoculation; A3. After removing the slag from the molten iron obtained in step A2 at 1370℃, pour it into a mold containing 30% polyurethane foamed sand and perform ultrasonic treatment. Add a flow-inducing agent during the pouring process. A4. After pouring, slowly cool the casting in the sand mold to below 400°C and remove it from the mold.
[0055] The amount of spheroidizing agent added is 1.2 wt% based on the weight percentage of the molten iron.
[0056] The amount of inoculant added is 0.5 wt% of the weight percentage of the molten iron.
[0057] The amount of covering agent added is 0.3 wt% of the weight of the molten iron.
[0058] The amount of metallic antimony added is 0.006 wt% based on the weight percentage of the molten iron.
[0059] The amount of inoculant added is 0.2 wt% based on the weight percentage of the molten iron.
[0060] The ultrasonic intensity of the ultrasonic treatment was 600W, and the ultrasonic duration was 20s.
[0061] The elements and contents of the casting composition include: 3.8wt%C, 1.97wt%Si, 0.137wt%Mn, 0.022wt%P, 0.007wt%S, 0.039wt%Mg, 0.007wt%Re, 0.0053wt%Sb, 0.50wt%Ni, 0.30wt%Mo, with the remainder being iron.
[0062] Comparative Example 1 A method for preparing a low-temperature impact-resistant ductile iron material for wind power, comprising the following steps: A1. Add scrap steel, carbon raiser, molybdenum wire, pig iron, and recycled material into the medium frequency furnace in sequence. After all the furnace materials have melted, sprinkle slag remover to remove slag from the molten iron. When the smelting temperature reaches 1520℃, allow it to stand at high temperature and remove slag. When the molten iron temperature reaches 1430℃, it is ready to be taken out of the furnace and spheroidized. A2. Add the spheroidizing agent, inoculant, metallic antimony, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A2 into the ladle for spheroidizing and inoculation; A3. After removing the slag from the molten iron obtained in step A2 at 1360℃, pour it into a mold containing 30% polyurethane foamed sand and perform ultrasonic treatment. Add a flow-inducing agent during the pouring process. A4. After pouring, slowly cool the casting in the sand mold to below 400°C and remove it from the mold.
[0063] The amount of spheroidizing agent added is 1 wt% of the weight percentage of the molten iron.
[0064] The amount of inoculant added is 0.4 wt% of the weight of the molten iron.
[0065] The amount of covering agent added is 0.2 wt% of the weight of the molten iron.
[0066] The amount of antimony metal added is 0.005 wt% based on the weight percentage of the molten iron.
[0067] The amount of inoculant added is 0.15 wt% based on the weight percentage of the molten iron.
[0068] The ultrasonic intensity of the ultrasonic treatment was 600W, and the ultrasonic duration was 30s.
[0069] The elements and contents of the casting composition include: 3.8wt%C, 1.97wt%Si, 0.139wt%Mn, 0.022wt%P, 0.007wt%S, 0.038wt%Mg, 0.006wt%Re, 0.0044wt%Sb, 0.18wt%Mo, with the remainder being iron.
[0070] Comparative Example 2 A method for preparing a low-temperature impact-resistant ductile iron material for wind power, comprising the following steps: A1. Add scrap steel, carbon raiser, pig iron, recycled material and pure nickel plate into the medium frequency furnace in sequence. After all the furnace materials have melted, sprinkle slag remover to remove slag from the molten iron. When the smelting temperature reaches 1520℃, allow it to stand at high temperature and remove slag. When the molten iron temperature reaches 1430℃, it is ready to be taken out of the furnace and spheroidized. A2. Add the spheroidizing agent, inoculant, metallic antimony, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A2 into the ladle for spheroidizing and inoculation; A3. After removing the slag from the molten iron obtained in step A2 at 1360℃, pour it into a mold containing 30% polyurethane foamed sand and perform ultrasonic treatment. Add a flow-inducing agent during the pouring process. A4. After pouring, slowly cool the casting in the sand mold to below 400°C and remove it from the mold.
[0071] The amount of spheroidizing agent added is 1 wt% of the weight percentage of the molten iron.
[0072] The amount of inoculant added is 0.4 wt% of the weight of the molten iron.
[0073] The amount of covering agent added is 0.2 wt% of the weight of the molten iron.
[0074] The amount of antimony metal added is 0.005 wt% based on the weight percentage of the molten iron.
[0075] The amount of inoculant added is 0.15 wt% based on the weight percentage of the molten iron.
[0076] The ultrasonic intensity of the ultrasonic treatment was 600W, and the ultrasonic duration was 30s.
[0077] The elements and contents of the casting composition include: 3.8wt%C, 1.97wt%Si, 0.139wt%Mn, 0.022wt%P, 0.007wt%S, 0.038wt%Mg, 0.006wt%Re, 0.0044wt%Sb, 0.42wt%Ni, with the remainder being iron.
[0078] Comparative Example 3 A method for preparing a low-temperature impact-resistant ductile iron material for wind power, comprising the following steps: A1. Add scrap steel, carbon raiser, pig iron, and recycled material into the medium frequency furnace in sequence. After all the furnace materials have melted, sprinkle slag remover to remove slag from the molten iron. When the smelting temperature reaches 1520℃, allow it to stand at high temperature and remove slag. When the molten iron temperature reaches 1430℃, it is ready to be taken out of the furnace and spheroidized. A2. Add the spheroidizing agent, inoculant, metallic antimony, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A2 into the ladle for spheroidizing and inoculation; A3. After removing the slag from the molten iron obtained in step A2 at 1360℃, pour it into a mold containing 30% polyurethane foamed sand and perform ultrasonic treatment. Add a flow-inducing agent during the pouring process. A4. After pouring, slowly cool the casting in the sand mold to below 400°C and remove it from the mold.
[0079] The amount of spheroidizing agent added is 1 wt% of the weight percentage of the molten iron.
[0080] The amount of inoculant added is 0.4 wt% of the weight of the molten iron.
[0081] The amount of covering agent added is 0.2 wt% of the weight of the molten iron.
[0082] The amount of antimony metal added is 0.005 wt% based on the weight percentage of the molten iron.
[0083] The amount of inoculant added is 0.15 wt% based on the weight percentage of the molten iron.
[0084] The ultrasonic intensity of the ultrasonic treatment was 600W, and the ultrasonic duration was 30s.
[0085] The elements and contents of the casting composition include: 3.8wt%C, 1.97wt%Si, 0.139wt%Mn, 0.022wt%P, 0.007wt%S, 0.038wt%Mg, 0.006wt%Re, 0.0044wt%Sb, with the remainder being iron.
[0086] Comparative Example 4 A method for preparing a low-temperature impact-resistant ductile iron material for wind power, comprising the following steps: A1. Add scrap steel, carbon raiser, molybdenum wire, pig iron, recycled material and pure nickel plate into the medium frequency furnace in sequence. After all the furnace materials have melted, sprinkle slag remover to remove slag from the molten iron. When the smelting temperature reaches 1520℃, allow it to stand at high temperature and remove slag. When the molten iron temperature reaches 1430℃, it is ready to be taken out of the furnace and spheroidized. A2. Add the spheroidizing agent, inoculant, metallic antimony, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A2 into the ladle for spheroidizing and inoculation; A3. After removing the slag from the molten iron obtained in step A2 at 1360℃, pour it into the mold, adding a flow-inducing agent during the pouring process; A4. After pouring, slowly cool the casting in the sand mold to below 400°C and remove it from the mold.
[0087] The amount of spheroidizing agent added is 1 wt% of the weight percentage of the molten iron.
[0088] The amount of inoculant added is 0.4 wt% of the weight of the molten iron.
[0089] The amount of covering agent added is 0.2 wt% of the weight of the molten iron.
[0090] The amount of antimony metal added is 0.005 wt% based on the weight percentage of the molten iron.
[0091] The amount of inoculant added is 0.15 wt% based on the weight percentage of the molten iron.
[0092] The elements and contents of the casting composition include: 3.8wt%C, 1.97wt%Si, 0.139wt%Mn, 0.022wt%P, 0.007wt%S, 0.038wt%Mg, 0.006wt%Re, 0.0044wt%Sb, 0.42wt%Ni, 0.18wt%Mo, and the remainder is iron.
[0093] Comparative Example 5 A method for preparing a low-temperature impact-resistant ductile iron material for wind power, comprising the following steps: A1. Add scrap steel, carbon raiser, pig iron, and recycled material into the medium frequency furnace in sequence. After all the furnace materials have melted, sprinkle slag remover to remove slag from the molten iron. When the smelting temperature reaches 1520℃, allow it to stand at high temperature and remove slag. When the molten iron temperature reaches 1430℃, it is ready to be taken out of the furnace and spheroidized. A2. Add the spheroidizing agent, inoculant, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A2 into the ladle for spheroidizing and inoculation; A3. After removing the slag from the molten iron obtained in step A2 at 1360℃, pour it into the mold and perform ultrasonic treatment. Add a flow-inducing agent during the pouring process. A4. After pouring, slowly cool the casting in the sand mold to below 400°C and remove it from the mold.
[0094] The amount of spheroidizing agent added is 1 wt% of the weight percentage of the molten iron.
[0095] The amount of inoculant added is 0.4 wt% of the weight of the molten iron.
[0096] The amount of covering agent added is 0.2 wt% of the weight of the molten iron.
[0097] The amount of inoculant added is 0.15 wt% based on the weight percentage of the molten iron.
[0098] The elements and contents of the casting composition include: 3.8wt%C, 1.97wt%Si, 0.139wt%Mn, 0.022wt%P, 0.007wt%S, 0.038wt%Mg, 0.006wt%Re, 0.0044wt%Sb, with the remainder being iron. Example of effect
[0099] Table 1 below shows the performance test results of the 70×70×170mm low-temperature impact resistant ductile iron materials for wind power prepared in Examples 1-3 and Comparative Examples 1-5: Table 1
[0100] Table 1 shows that the strength of the low-temperature impact resistant ductile iron materials for wind power prepared in Examples 1-3 and Comparative Examples 1-5 meets the requirements of QT400-18L-2.
[0101] The difference between Comparative Example 1 and Example 2 is that no nickel was added; the difference between Comparative Example 2 and Example 2 is that no molybdenum was added; the difference between Comparative Example 3 and Example 2 is that neither nickel nor molybdenum was added; the difference between Comparative Example 4 and Example 2 is that no ultrasonic treatment was performed; and the difference between Comparative Example 5 and Example 2 is that neither nickel nor molybdenum was added, nor was ultrasonic treatment performed. Comparatively, the strength of Example 2 meets the requirements of QT400-18L-2, and its low-temperature impact performance is better. In summary, Example 2, by introducing nickel and molybdenum elements during the smelting process, introducing antimony elements during the spheroidization inoculation stage, and combining this with the ultrasonic treatment process during casting, produces a low-temperature impact resistant ductile iron material for wind power that meets the high strength requirements of QT400-18AL while possessing excellent low-temperature impact resistance.
[0102] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific 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. A method for preparing a low-temperature impact-resistant ductile iron material for wind power, characterized in that, The preparation steps include: A1. Material preparation; A2. Add scrap steel, carbon raiser, molybdenum wire, pig iron, recycled material, and pure nickel plate into the medium frequency furnace in sequence. After all the furnace materials have melted, let them stand and remove slag. A3. Add the spheroidizing agent, inoculant, metallic antimony, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A2 into the ladle for spheroidizing and inoculation; A4. After removing the slag from the molten iron obtained in step A3, pour it into the mold and perform ultrasonic treatment. Add a flow-inducing agent during the pouring process. A5. After pouring, slowly cool the casting in the sand mold to below 400°C and remove it from the mold.
2. The method for preparing low-temperature impact resistant ductile iron material for wind power according to claim 1, characterized in that, The materials prepared in the preparation step include, by weight percentage: 40-60 wt% pig iron, 20-30 wt% recycled material, 10-20 wt% scrap steel, 0.3-0.5 wt% molybdenum wire, and 0.2-0.6 wt% pure nickel.
3. The method for preparing low-temperature impact resistant ductile iron material for wind power according to claim 1, characterized in that, The elements and contents of the casting composition include: 3.8wt%C, 1.94~1.97wt%Si, 0.131~0.139wt%Mn, 0.022wt%P, 0.007wt%S, 0.038~0.039wt%Mg, 0.006~0.007wt%Re, 0.0028~0.0053wt%Sb, 0.30~0.50wt%Ni, 0.1~0.3wt%Mo, and the remainder is iron.
4. The method for preparing low-temperature impact resistant ductile iron material for wind power according to claim 1, characterized in that, The inoculant is a silicon-calcium-barium inoculant, whose main components include 60-80% Si, 1.5-5% Ba, and 0.2-1.0% Ca; the amount of the inoculant added is 0.3-0.5 wt% based on the weight percentage of the molten iron.
5. The method for preparing low-temperature impact resistant ductile iron material for wind power according to claim 1, characterized in that, The amount of the covering agent added is 0.2~0.3 wt% of the weight of the molten iron.
6. The method for preparing low-temperature impact resistant ductile iron material for wind power according to claim 1, characterized in that, The amount of antimony metal added is 0.003~0.006 wt% based on the weight percentage of the molten iron.
7. The method for preparing low-temperature impact-resistant ductile iron material for wind power according to claim 1, characterized in that, The in-flow inoculant is a sulfur-oxygen inoculant, whose main components include 68~80wt%Si, 0.5~1.5wt%Ca, and 0.5~1.5wt%Al; the amount of in-flow inoculant added is 0.1~0.2wt% based on the weight percentage of the molten iron.
8. The method for preparing low-temperature impact resistant ductile iron material for wind power according to claim 1, characterized in that, The ultrasonic intensity of the ultrasonic treatment is 400~600W, and the ultrasonic duration is 20~30s.
9. The method for preparing low-temperature impact resistant ductile iron material for wind power according to claim 1, characterized in that, The molding sand contains polyurethane foam.
10. A low-temperature impact-resistant ductile iron material for wind power, characterized in that, The low-temperature impact resistant ductile iron material for wind power is prepared by the method described in any one of claims 1 to 9.