High-strength wear-resistant wind power ductile iron and processing technology thereof
By optimizing the microstructure of ductile iron for wind power through niobium-iron alloying and pulsed current treatment, the problem of brittle fracture of ductile iron for wind power in low-temperature environments was solved, achieving a balance between high strength and wear resistance, and reducing costs.
Patent Information
- Application Number
- CN202511789397.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-01
- Publication Date
- 2026-02-06
AI Technical Summary
Existing ductile iron materials for wind power have difficulty maintaining excellent low-temperature impact toughness while improving room temperature tensile strength, which leads to brittle fracture in extreme low-temperature environments, and the use of precious metal Ni increases costs.
By employing niobium-iron alloying, combined with spheroidization inoculation of antimony and titanium carbide particles, and pulsed current quenching and normalizing treatment, the microstructure of the material is optimized, the grains are refined, and the toughness is improved.
High-strength, wear-resistant ductile iron for wind power was prepared, meeting the QT500-14AL standard. It possesses excellent low-temperature impact resistance and wear resistance, thus reducing material costs.
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Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the technical field of casting, in particular to a high-strength wear-resistant wind power ductile iron and a processing technology thereof. BACKGROUND
[0002] With the increasing demand for renewable energy worldwide, wind power, as an important part of clean energy, has a continuously expanding installed capacity. Wind power equipment key components such as hubs, main shaft bearing seats, gear box housings and other castings have long served in complex and even extreme cold environments, thus putting forward extremely strict requirements on their material performance. In particular, wind power ductile iron castings not only need to meet the high-strength requirements of conventional ductile iron at room temperature, but also must have excellent low-temperature impact toughness to ensure that brittle fracture does not occur in low-temperature environments, thus ensuring the safety and reliability of the whole machine operation.
[0003] However, in the ductile iron material system, there is often a significant mutual restraint relationship between room temperature tensile strength and low-temperature impact toughness: increasing the strength usually leads to the refinement of the matrix structure or the increase of the proportion of pearlite, thus reducing the plasticity and toughness of the material; and pursuing high toughness may sacrifice part of the strength index. This contradiction makes the technical development of wind power ductile iron much more difficult than that of general industrial field ductile iron products.
[0004] At present, ferrite-based ductile iron is generally used for wind power castings, and its core goal is to significantly improve the low-temperature impact performance to more than 7 J on the premise that the tensile strength is not less than 460 MPa. Therefore, the material composition design needs to achieve a fine balance between strength and toughness. Traditional methods mainly control the carbon equivalent and optimize the spheroidizing and inoculation treatment process to regulate the matrix structure, but it is difficult to simultaneously consider high strength and high toughness.
[0005] In recent years, alloying has become an important way to improve the comprehensive performance of wind power ductile iron. Research has found that appropriate addition of alloying elements such as Sn, Cu, V, Ni, Nb, etc. can improve the structure and performance to some extent. Among them, Sn and Cu are pearlite stabilizing elements, which can help improve the strength, but may weaken the low-temperature toughness; V, as a strong carbide-forming element, can refine the grains and increase the hardness, but is easy to cause brittle phase precipitation; compared with the above, Ni has been widely proven to effectively improve the strength and low-temperature impact energy without significantly reducing the toughness, especially in the early stage of material development. However, Ni is a noble metal, and the addition amount needs to reach about 0.4% to meet the technical indicators of QT500-14AL, which leads to a substantial increase in material cost.
[0006] Therefore, it is urgent to develop a high-strength wear-resistant wind power ductile iron that meets the requirements of QT500-14AL and has excellent low-temperature impact performance. SUMMARY
[0007] The application aims to provide a high-strength wear-resistant wind power ductile iron and a processing technology thereof to solve the technical problems mentioned in the background.
[0008] The technical solution for achieving the application is as follows: In a first aspect, the application provides a processing technology of high-strength wear-resistant wind power ductile iron, and the process steps include: A1. Waste steel, carbon additive, pig iron, return material, and niobium iron are sequentially added into a medium-frequency furnace, and after all the furnace materials are melted, static setting and slag removal are performed to obtain an iron liquid; A2. A spheroidizing agent, an inoculant, metallic antimony, titanium carbide particles, and a covering agent are sequentially added into the bottom of a ladle, and then the iron liquid of step A1 is poured into the ladle to perform spheroidizing and inoculation; A3. The iron liquid after spheroidizing and inoculation is poured into a casting mold after slagging, and a stream inoculant is added during pouring; A4. After pouring is completed, the casting is slowly cooled to below 400°C in the sand mold, and the casting is removed from the mold; A5. The casting is first subjected to pulse current quenching treatment, and then subjected to pulse current normalizing treatment to obtain high-strength wear-resistant wind power ductile iron.
[0009] Further, the elements and contents of the casting components mainly include 3.6-3.7wt% C, 2.4-2.5wt% Si, Mn≤0.20wt%, P≤0.035wt%, 0.005-0.015wt% S, 0.035-0.05wt% Mg, Re≤0.015wt%, 0.03-0.2wt% Nb, 0.0028-0.0050wt% Sb, and the rest is iron and impurities brought in during the preparation process.
[0010] Further, the titanium carbide particles are added in an amount of 0.2-0.3wt% based on the weight percentage of the tapped iron liquid.
[0011] Further, the metallic antimony is added in an amount of 0.003-0.006wt% based on the weight percentage of the tapped iron liquid.
[0012] Further, the spheroidizing agent uses a rare earth-containing silicon-magnesium spheroidizing agent, and the main components include 4.5-6.5wt% Mg, 0.4-0.6wt% Re, and 40-50wt% Si.
[0013] Further, the inoculant uses a silicon-calcium-barium inoculant, and the main components include 60-80wt% Si, 1.5-2.5wt% Ba, and 0.2-1.0wt% Ca; the inoculant is added in an amount of 0.3-0.5wt% based on the weight percentage of the tapped iron liquid.
[0014] Further, the main components of the stream inoculant include 68-80wt% Si, 0.5-1.5wt% Ca, and 0.5-1.5wt% Al; the stream inoculant is added in an amount of 0.1-0.2wt% based on the weight percentage of the tapping molten iron.
[0015] Further, the pouring temperature is 1350-1370℃.
[0016] Further, the pulse current quenching treatment and the pulse current normalizing treatment have a pulse voltage of 5V, wherein the highest temperature of the pulse current quenching treatment is 950-985℃, and the highest temperature of the pulse current quenching treatment is 780-840℃.
[0017] In a second aspect, the present application provides a high-strength wear-resistant wind power ductile iron, which is prepared by the processing technology of the high-strength wear-resistant wind power ductile iron.
[0018] By adopting the above technical scheme, the present application has the following beneficial effects: The processing technology of the high-strength wear-resistant wind power ductile iron has the following specific steps: first, waste steel, carbonizer, pig iron, return material, and niobium iron are sequentially added into a medium-frequency furnace, and after all the furnace charges are completely melted, the molten iron with uniform composition is obtained by standing and deslagging; then, a spheroidizing agent, an inoculant, metallic antimony, titanium carbide particles, and a covering agent are sequentially laid at the bottom of a ladle, and the above molten iron is poured into the ladle to perform spheroidizing treatment and inoculation treatment; then, the molten iron after spheroidizing and inoculation is deslagged, and is poured into a casting mold, and a stream inoculant is synchronously added during the pouring process to further refine the structure; after pouring is completed, the casting is slowly cooled to below 400℃ in the sand mold, and is then removed from the casting mold; finally, the casting is subjected to pulse current quenching treatment, and then pulse current normalizing treatment, so that the high-strength wear-resistant wind power ductile iron with high strength, good wear resistance, and low-temperature impact performance meeting the requirements of QT500-14AL is finally obtained.
[0019] In the melting stage, the high-strength wear-resistant wind power ductile iron of the present application adds niobium iron to introduce niobium element, and niobium as a strong carbide and nitride forming element can combine with carbon and nitrogen to generate fine and dispersed distribution of NbC and other precipitated phases during the solidification process, effectively inhibiting the growth of austenite grains, significantly refining the as-cast structure, and thus improving the strength and toughness of the material; secondly, the micro-alloying effect of niobium can promote the homogenization of the ferrite matrix, and further improve the matrix strength through precipitation strengthening in the subsequent heat treatment process, while maintaining good plasticity and low-temperature impact performance; in addition, the fine NbC hard phase is uniformly distributed in the matrix, improving the hardness and wear resistance of the material.
[0020] The high-strength wear-resistant ductile iron for wind power of this invention introduces antimony and titanium carbide particles during the spheroidization and inoculation stages. Antimony, as a weak anti-spheroidizing element, effectively inhibits graphite distortion, promotes the sphericity of graphite spheroids, and reduces the formation of fragmented or flower-shaped graphite, thereby improving the spheroidization rate and graphite distribution uniformity. The good spheroidization morphology not only reduces stress concentration but also provides a more uniform load-bearing structure for the matrix, which is beneficial to improving the strength and low-temperature impact toughness of the material. At the same time, titanium carbide particles, as heterogeneous nucleation cores with high melting point and high hardness, can serve as composite nucleation sites for graphite and austenite in molten iron, refining the eutectic size, promoting the precipitation of fine, dispersed spherical graphite, and inhibiting grain coarsening. In addition, the micron / submicron-sized TiC hard particles remaining in the matrix have excellent wear resistance and can significantly enhance the wear resistance of the material.
[0021] In the preparation of the high-strength wear-resistant ductile iron for wind power of the present invention, the casting is first subjected to pulse current quenching treatment, followed by pulse current normalizing treatment. First, the pulse current quenching utilizes a high-density, short-duration pulse current passing through the casting to generate a strong Joule heating effect and electroplastic effect inside the material, which promotes rapid heating of the matrix and achieves local austenitization. Then, the quenching is completed by relying on the heat conduction of the casting itself or by controlling the cooling rate, forming a fine and dispersed bainite or low-carbon martensite / retained austenite mixed structure, which effectively improves the material strength and surface hardness and enhances wear resistance. At the same time, the pulse current can promote dislocation movement and defect annihilation, reduce internal stress concentration, and avoid the cracking risk that is easily caused by traditional quenching. The subsequent pulsed current normalizing treatment applies a pulsed current slightly below the critical phase transformation temperature. Through the electric field-induced atomic diffusion and grain boundary migration, it promotes uniform and fine recrystallization of the quenched structure, resulting in a balanced structure dominated by fine-grained ferrite and supplemented by a small amount of pearlite or bainite. This not only further refines the grains and improves toughness, but also effectively releases residual stress and significantly improves low-temperature impact performance. Furthermore, the non-thermal effect of the pulsed current can accelerate the uniform distribution of alloying elements such as niobium, suppress harmful segregation, and optimize the morphology and distribution of carbides, thereby improving plasticity and low-temperature toughness without sacrificing strength.
[0022] This invention introduces niobium during the smelting process, adds antimony during the spheroidization inoculation stage, and combines a composite process of first performing pulse current quenching and then pulse current normalizing on the castings. This synergistically optimizes the microstructure and mechanical properties of the material, resulting in high-strength wear-resistant ductile iron for wind power that not only has excellent strength and wear resistance, but also fully meets the requirements of the QT500-14AL standard for low-temperature impact performance. Detailed Implementation
[0023] To better understand the above technical solution, the following will provide a detailed explanation of the technical solution in conjunction with specific implementation methods.
[0024] 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.
[0025] 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.
[0026] 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%.
[0027] 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%.
[0028] The recycled material is ferritic ductile iron recycled material.
[0029] The covering agent uses rust-free iron filings with a particle size of 1~2mm.
[0030] The niobium-iron alloy is FeNb60, with a niobium content of 60~65wt%.
[0031] The spheroidizing agent is a rare earth silicon-magnesium spheroidizing agent, whose main components include 4.5~6.5wt%Mg, 0.4~0.6wt%Re, and 40~50wt%Si; the remainder is iron, and the particle size is 4~10 mm.
[0032] The carbon raiser is a high-temperature graphitized carbon raiser with a fixed carbon content of ≥ 99.0% and a particle size of 0.5~5.0 mm.
[0033] 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 inoculant uses a silicon-calcium-barium inoculant, whose main components include 60-80% Si, 1.5-5% Ba, and 0.2-1.0% Ca.
[0034] The preparation steps of titanium carbide particles include: mixing titanium carbide with a particle size of about 100 nm and spherical iron powder with a particle size of 10 μm at a mass ratio of 1:1, and then mixing it with agate grinding balls with particle sizes of 12 mm and 6 mm, which are 4 times the mass of titanium carbide, and ball milling at 400 r / min for 6 h, stopping for 10 min every 20 min of ball milling, to obtain titanium carbide particles.
[0035] Example A processing technology for high-strength wear-resistant ductile iron for wind power, the process steps include: A1. Adding scrap steel, carbon raiser, pig iron, recycled material and ferroniobium into an intermediate frequency furnace in sequence. After all the furnace materials have melted, when the smelting temperature reaches 1500~1530℃, the furnace is subjected to high-temperature settling and slag removal. When the molten iron temperature reaches 1400~1450℃, the molten iron is then taken out of the furnace and spheroidized. A2. Add the spheroidizing agent, inoculant, metallic antimony, titanium carbide particles, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A1 into the ladle for spheroidizing and inoculation; A3. After slag removal, pour the molten iron, which has been spheroidized and inoculated at 1350~1370℃, into the mold, and add a flow-inoculating 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; A5. The casting is first treated with a 5V pulse voltage for 320~340ms, then water-quenched, and then air-cooled for 240~258ms under a 5V pulse voltage to obtain high-strength wear-resistant ductile iron for wind power.
[0036] The elements and contents of the casting composition mainly include: 3.63~3.69wt%C, 2.39~2.49wt%Si, 0.113~0.139wt%Mn, 0.027~0.028wt%P, 0.006~0.007wt%S, 0.039~0.043wt%Mg, 0.008~0.011wt%Re, 0.03~0.2wt%Nb, and 0.0028~0.0050wt%Sb.
[0037] The amount of titanium carbide particles added is 0.2~0.3 wt% based on the weight percentage of the molten iron.
[0038] The amount of metallic antimony added is 0.003~0.006 wt% based on the weight percentage of the molten iron.
[0039] The spheroidizing agent is a rare earth silicon-magnesium spheroidizing agent, whose main components include 4.5~6.5wt%Mg, 0.4~0.6wt%Re, and 40~50wt%Si; the amount added by weight percentage of the molten iron is 0.9~1.2wt%.
[0040] The amount of inoculant added is 0.3~0.5 wt% of the weight of the molten iron.
[0041] The amount of inoculant added is 0.1~0.2wt% based on the weight percentage of the molten iron.
[0042] Example 1 A processing technology for high-strength, wear-resistant ductile iron for wind turbines, comprising the following steps: A1. Add scrap steel, carbon raiser, pig iron, recycled material and ferroniobium into the medium frequency furnace in sequence. After all the furnace materials have melted, 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, titanium carbide particles, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A1 into the ladle for spheroidizing and inoculation; A3. After slag removal, the molten iron that has been spheroidized and inoculated at 1350℃ is poured into the mold, and an inoculant is added 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; A5. The casting is first treated with a 5V pulse voltage for 320ms, at which time the highest temperature is 945℃, then water-quenched, and then treated with a 5V pulse voltage for 240ms, at which time the highest temperature is 780℃, and then air-cooled to obtain high-strength wear-resistant ductile iron for wind power.
[0043] The elements and contents of the casting composition mainly include: 3.69wt%C, 2.39wt%Si, 0.118wt%Mn, 0.028wt%P, 0.006wt%S, 0.043wt%Mg, 0.011wt%Re, 0.03wt%Nb, and 0.0028wt%Sb.
[0044] The amount of titanium carbide particles added is 0.2 wt% of the weight of the molten iron.
[0045] The amount of antimony metal added is 0.003 wt% based on the weight percentage of the molten iron.
[0046] The spheroidizing agent is a rare earth silicon-magnesium spheroidizing agent, and the amount added is 1.2 wt% based on the weight percentage of the molten iron.
[0047] The amount of inoculant added is 0.3 wt% of the weight of the molten iron.
[0048] The amount of inoculant added is 0.1 wt% based on the weight percentage of the molten iron.
[0049] Example 2 A processing technology for high-strength, wear-resistant ductile iron for wind turbines, comprising the following steps: A1. Add scrap steel, carbon raiser, pig iron, recycled material and ferroniobium into the medium frequency furnace in sequence. After all the furnace materials have melted, when the smelting temperature reaches 1510℃, allow it to stand at high temperature and remove slag. When the molten iron temperature reaches 1410℃, it is ready to be taken out of the furnace and spheroidized. A2. Add the spheroidizing agent, inoculant, metallic antimony, titanium carbide particles, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A1 into the ladle for spheroidizing and inoculation; A3. After slag removal, the molten iron that has been spheroidized and inoculated at 1355℃ is poured into the mold, and an inoculant is added 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; A5. The casting is first treated with a 5V pulse voltage for 325ms, then water-quenched, and then air-cooled for 244ms under a 5V pulse voltage to obtain high-strength wear-resistant ductile iron for wind power.
[0050] The elements and contents of the casting composition mainly include: 3.63wt%C, 2.49wt%Si, 0.119wt%Mn, 0.028wt%P, 0.007wt%S, 0.039wt%Mg, 0.01wt%Re, 0.05wt%Nb, and 0.0033wt%Sb.
[0051] The amount of titanium carbide particles added is 0.23 wt% based on the weight percentage of the molten iron.
[0052] The amount of metallic antimony added is 0.004 wt% based on the weight percentage of the molten iron.
[0053] The spheroidizing agent used is a rare earth silicon-magnesium spheroidizing agent, and the amount added is 1 wt% of the weight percentage of the molten iron.
[0054] The amount of inoculant added is 0.4 wt% of the weight of the molten iron.
[0055] The amount of inoculant added is 0.15 wt% based on the weight percentage of the molten iron.
[0056] Example 3 A processing technology for high-strength, wear-resistant ductile iron for wind turbines, comprising the following steps: A1. Add scrap steel, carbon raiser, pig iron, recycled material and ferroniobium into the medium frequency furnace in sequence. After all the furnace materials have melted, when the smelting temperature reaches 1520℃, allow it to stand at high temperature and remove slag. When the molten iron temperature reaches 1420℃, it is ready to be taken out of the furnace and spheroidized. A2. Add the spheroidizing agent, inoculant, metallic antimony, titanium carbide particles, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A1 into the ladle for spheroidizing and inoculation; A3. After slag removal, the molten iron that has been spheroidized and inoculated at 1360℃ is poured into the mold, and an inoculant is added 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; A5. The casting is first treated with a 5V pulse voltage for 330ms, then water-quenched, and then air-cooled for 248ms under a 5V pulse voltage to obtain high-strength wear-resistant ductile iron for wind power.
[0057] The elements and contents of the casting composition mainly include: 3.68wt%C, 2.49wt%Si, 0.113wt%Mn, 0.027wt%P, 0.007wt%S, 0.043wt%Mg, 0.010wt%Re, 0.1wt%Nb, and 0.0038wt%Sb.
[0058] The amount of titanium carbide particles added is 0.26 wt% of the weight of the molten iron.
[0059] The amount of metallic antimony added is 0.004 wt% based on the weight percentage of the molten iron.
[0060] The spheroidizing agent is a rare earth silicon-magnesium spheroidizing agent, and the amount added is 1.2 wt% based on the weight percentage of the molten iron.
[0061] The amount of inoculant added is 0.4 wt% of the weight of the molten iron.
[0062] The amount of inoculant added is 0.15 wt% based on the weight percentage of the molten iron.
[0063] Example 4 A processing technology for high-strength, wear-resistant ductile iron for wind turbines, comprising the following steps: A1. Add scrap steel, carbon raiser, pig iron, recycled material and ferroniobium into the medium frequency furnace in sequence. After all the furnace materials have melted, 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, titanium carbide particles, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A1 into the ladle for spheroidizing and inoculation; A3. After removing the slag from the molten iron that has been spheroidized and inoculated at 1370℃, pour it into the mold, adding a flow-inoculating 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; A5. The casting is first treated with a 5V pulse voltage for 340ms, then water-quenched, and then air-cooled for 258ms under a 5V pulse voltage to obtain high-strength wear-resistant ductile iron for wind power.
[0064] The elements and contents of the casting composition mainly include: 3.64wt%C, 2.47wt%Si, 0.139wt%Mn, 0.027wt%P, 0.007wt%S, 0.040wt%Mg, 0.008wt%Re, 0.2wt%Nb, and 0.0050wt%Sb.
[0065] The amount of titanium carbide particles added is 0.3 wt% of the weight of the molten iron.
[0066] The amount of antimony metal added is 0.006 wt% based on the weight percentage of the molten iron.
[0067] The spheroidizing agent is a rare earth silicon-magnesium spheroidizing agent, and the addition amount is 0.9 wt% based on the weight percentage of the molten iron.
[0068] The amount of inoculant added is 0.5 wt% of the weight percentage of the molten iron.
[0069] The amount of inoculant added is 0.2 wt% based on the weight percentage of the molten iron.
[0070] Comparative Example 1 A processing technology for high-strength, wear-resistant ductile iron for wind turbines, comprising the following steps: A1. Add scrap steel, carbon raiser, pig iron, recycled material and ferroniobium into the medium frequency furnace in sequence. After all the furnace materials have melted, 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, titanium carbide particles, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A1 into the ladle for spheroidizing and inoculation; A3. After removing the slag from the molten iron that has been spheroidized and inoculated at 1350℃, pour it into the mold, adding a flow-inoculating 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; A5. The casting is first treated with a 5V pulse voltage for 320ms, at which time the highest temperature is 945℃, then water-quenched, and then treated with a 5V pulse voltage for 240ms, at which time the highest temperature is 780℃, and then air-cooled to obtain high-strength wear-resistant ductile iron for wind power.
[0071] The elements and contents of the casting composition mainly include: 3.69wt%C, 2.39wt%Si, 0.118wt%Mn, 0.028wt%P, 0.006wt%S, 0.043wt%Mg, 0.011wt%Re, and 0.03wt%Nb.
[0072] The amount of titanium carbide particles added is 0.2 wt% of the weight of the molten iron.
[0073] The spheroidizing agent is a rare earth silicon-magnesium spheroidizing agent, and the amount added is 1.2 wt% based on the weight percentage of the molten iron.
[0074] The amount of inoculant added is 0.3 wt% of the weight of the molten iron.
[0075] The amount of inoculant added is 0.1 wt% based on the weight percentage of the molten iron.
[0076] Comparative Example 2 A processing technology for high-strength, wear-resistant ductile iron for wind turbines, comprising the following steps: A1. Add scrap steel, carbon raiser, pig iron, recycled material and ferroniobium into the medium frequency furnace in sequence. After all the furnace materials have melted, 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 A1 into the ladle for spheroidizing and inoculation; A3. After slag removal, the molten iron that has been spheroidized and inoculated at 1350℃ is poured into the mold, and an inoculant is added 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; A5. The casting is first treated with a 5V pulse voltage for 320ms, at which time the highest temperature is 945℃, then water-quenched, and then treated with a 5V pulse voltage for 240ms, at which time the highest temperature is 780℃, and then air-cooled to obtain high-strength wear-resistant ductile iron for wind power.
[0077] The elements and contents of the casting composition mainly include: 3.69wt%C, 2.39wt%Si, 0.118wt%Mn, 0.028wt%P, 0.006wt%S, 0.043wt%Mg, 0.011wt%Re, 0.03wt%Nb, and 0.0028wt%Sb.
[0078] The amount of antimony metal added is 0.003 wt% based on the weight percentage of the molten iron.
[0079] The spheroidizing agent is a rare earth silicon-magnesium spheroidizing agent, and the amount added is 1.2 wt% based on the weight percentage of the molten iron.
[0080] The amount of inoculant added is 0.3 wt% of the weight of the molten iron.
[0081] The amount of inoculant added is 0.1 wt% based on the weight percentage of the molten iron.
[0082] Comparative Example 3 A processing technology for high-strength, wear-resistant ductile iron for wind turbines, comprising the following steps: A1. Add scrap steel, carbon raiser, pig iron, recycled material and ferroniobium into the medium frequency furnace in sequence. After all the furnace materials have melted, 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, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A1 into the ladle for spheroidizing and inoculation; A3. After removing the slag from the molten iron that has been spheroidized and inoculated at 1350℃, pour it into the mold, adding a flow-inoculating 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; A5. The casting is first treated with a 5V pulse voltage for 320ms, at which time the highest temperature is 945℃, then water-quenched, and then treated with a 5V pulse voltage for 240ms, at which time the highest temperature is 780℃, and then air-cooled to obtain high-strength wear-resistant ductile iron for wind power.
[0083] The elements and contents of the casting composition mainly include: 3.69wt%C, 2.39wt%Si, 0.118wt%Mn, 0.028wt%P, 0.006wt%S, 0.043wt%Mg, 0.011wt%Re, 0.03wt%Nb, and 0.0028wt%Sb.
[0084] The spheroidizing agent is a rare earth silicon-magnesium spheroidizing agent, and the amount added is 1.2 wt% based on the weight percentage of the molten iron.
[0085] The amount of inoculant added is 0.3 wt% of the weight of the molten iron.
[0086] The amount of inoculant added is 0.1 wt% based on the weight percentage of the molten iron.
[0087] Comparative Example 4 A processing technology for high-strength, wear-resistant ductile iron for wind turbines, comprising the following steps: A1. Add scrap steel, carbon raiser, pig iron, recycled material and ferroniobium into the medium frequency furnace in sequence. After all the furnace materials have melted, 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, titanium carbide particles, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A1 into the ladle for spheroidizing and inoculation; A3. After removing the slag from the molten iron that has been spheroidized and inoculated at 1350℃, pour it into the mold, adding a flow-inoculating agent during the pouring process; A4. After pouring, the casting is slowly cooled to below 400°C in the sand mold and removed from the mold to obtain high-strength wear-resistant ductile iron for wind power.
[0088] The elements and contents of the casting composition mainly include: 3.69wt%C, 2.39wt%Si, 0.118wt%Mn, 0.028wt%P, 0.006wt%S, 0.043wt%Mg, 0.011wt%Re, 0.03wt%Nb, and 0.0028wt%Sb.
[0089] The amount of titanium carbide particles added is 0.2 wt% of the weight of the molten iron.
[0090] The amount of antimony metal added is 0.003 wt% based on the weight percentage of the molten iron.
[0091] The spheroidizing agent is a rare earth silicon-magnesium spheroidizing agent, and the amount added is 1.2 wt% based on the weight percentage of the molten iron.
[0092] The amount of inoculant added is 0.3 wt% of the weight of the molten iron.
[0093] The amount of inoculant added is 0.1 wt% based on the weight percentage of the molten iron.
[0094] Example of effect Wear resistance: Tested using an M2000 friction and wear testing machine. The friction method was rolling friction, the friction pair was a GCr15 material ring, the test load was 80N, and the friction pair rotation speed was 180r / min. The wear track width was measured at three locations every 5 minutes using a handheld microscope, and the average value was taken.
[0095] Table 1 below shows the performance test results of the 70×70×170mm high-strength wear-resistant ductile iron for wind power prepared in Examples 1-4 and Comparative Examples 1-4: Table 1
[0096] Table 1 shows that the high-strength wear-resistant ductile iron for wind power prepared in Examples 1-4 and Comparative Examples 1-4 has high strength, good wear resistance, and low-temperature impact resistance that meets the requirements of QT500-14AL.
[0097] The difference between Comparative Example 1 and Example 1 is that antimony was not added; the difference between Comparative Example 2 and Example 1 is that titanium carbide was not added; the difference between Comparative Example 3 and Example 1 is that neither antimony nor titanium carbide was added; and the difference between Comparative Example 4 and Example 1 is that the casting was not subjected to pulse current quenching followed by pulse current normalizing. Comparative Example 1, by not adding antimony but adding titanium carbide, showed reduced low-temperature impact resistance, indicating that the addition of titanium carbide affects the low-temperature impact resistance of the high-strength wear-resistant ductile iron for wind power. Example 1, by using antimony metal and pulse current quenching and normalizing, can improve the low-temperature toughness of the material while ensuring its overall low-temperature toughness. In summary, Example 1, 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 high-strength wear-resistant ductile iron for wind power with higher strength, better wear resistance, and low-temperature impact resistance meeting the requirements of QT500-14AL.
[0098] 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 processing technology for high-strength, wear-resistant ductile iron for wind turbines, characterized in that, The process steps include: A1. Add scrap steel, carbon raiser, pig iron, recycled material and ferroniobium into the medium frequency furnace in sequence. After all the furnace materials have melted, let it stand and remove slag to obtain molten iron. A2. Add the spheroidizing agent, inoculant, metallic antimony, titanium carbide particles, and covering agent to the bottom of the ladle in sequence, and then pour the molten iron from step A1 into the ladle for spheroidizing and inoculation; A3. After slag removal from the spheroidized and inoculated molten iron, pour it into the mold, adding a flow-through inoculant 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; A5. The casting is first subjected to pulse current quenching treatment, and then pulse current normalizing treatment to obtain high-strength wear-resistant ductile iron for wind power.
2. The processing technology of the high-strength wear-resistant ductile iron for wind power according to claim 1, characterized in that, The elements and contents of the casting composition mainly include: 3.6~3.7wt%C, 2.4~2.5wt%Si, Mn≤0.20wt%, P≤0.035wt%, 0.005~0.015wt%S, 0.035~0.05wt%Mg, Re≤0.015wt%, 0.03~0.2wt%Nb, 0.0028~0.0050wt%Sb, with the remainder being iron and impurities introduced during the preparation process.
3. The processing technology of the high-strength wear-resistant ductile iron for wind power according to claim 1, characterized in that, The amount of titanium carbide particles added is 0.2~0.3 wt% of the weight of the molten iron.
4. The processing technology of high-strength wear-resistant ductile iron 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.
5. The processing technology of the high-strength wear-resistant ductile iron for wind power according to claim 1, characterized in that, The spheroidizing agent is a rare earth silicon-magnesium spheroidizing agent, whose main components include 4.5~6.5wt%Mg, 0.4~0.6wt%Re, and 40~50wt%Si.
6. The processing technology of the high-strength wear-resistant ductile iron 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.
7. The processing technology of high-strength wear-resistant ductile iron for wind power according to claim 1, characterized in that, The main components of the in-flow inoculant include 68-80 wt% Si, 0.5-1.5 wt% Ca, and 0.5-1.5 wt% Al; the amount of in-flow inoculant added is 0.1-0.2 wt% based on the weight percentage of the molten iron.
8. The processing technology of high-strength wear-resistant ductile iron for wind power according to claim 1, characterized in that, The pouring temperature is 1350~1370℃.
9. The processing technology of high-strength wear-resistant ductile iron for wind power according to claim 1, characterized in that, The pulse voltage for both the pulse current quenching treatment and the pulse current normalizing treatment is 5V. The maximum temperature for the pulse current quenching treatment is 950~985℃, and the maximum temperature for the pulse current quenching treatment is 780~840℃.
10. A high-strength, wear-resistant ductile iron for wind turbines, characterized in that, The high-strength wear-resistant ductile iron for wind power is obtained by the processing technology of the high-strength wear-resistant ductile iron for wind power as described in any one of claims 1 to 9.