Manganese-based composite additive for high-strength wear-resistant steel as well as preparation method and application of manganese-based composite additive

Abstract

The invention relates to the technical field of metal additives, and discloses a manganese-based composite additive for high-strength wear-resistant steel and a preparation method and application of the manganese-based composite additive. Comprising 35-45% of low-phosphorus electrolytic manganese powder, 15-20% of nano manganese carbide, 10-15% of titanium-boron alloy powder, 8-12% of silicon-calcium alloy powder, 5-8% of calcium aluminate powder, 3-6% of calcium oxide powder and 2-5% of nano titanium dioxide. The preparation method comprises the steps of raw material pretreatment, graded premixing, low-temperature sintering and modified coating. According to the technical scheme, the problems that an existing manganese additive is single in function, poor in compatibility, high in cost and insufficient in environmental protection property are solved, the preparation process is simple, energy consumption is low, and the additive is suitable for an existing steelmaking production line and has extremely high popularization value in the field of high-strength wear-resistant steel production.

Description

Technical Field

[0001] This invention relates to the field of metal additives technology, specifically to a manganese-based composite additive for high-strength wear-resistant steel, its preparation method, and its application. Background Technology

[0002] In the steel industry, manganese additives are core auxiliary materials for improving steel performance, mainly used for deoxidation, desulfurization, and alloying. Especially in the production of wear-resistant steels (such as manganese steel and high-strength alloy steel), the amount and form of manganese added directly affect the hardness, wear resistance, and impact resistance of the steel. Currently, manganese additives for steelmaking are mainly ferromanganese (high-carbon, medium-carbon, and low-carbon ferromanganese), ferrosilicon manganese alloys, and electrolytic manganese. While these can basically meet the production needs of ordinary wear-resistant steels, the following technical problems exist: 1. Limited functionality: Existing manganese additives can only achieve basic deoxidation, desulfurization, and alloying, and cannot simultaneously improve the wear resistance and impact resistance of steel. Additional precious metal elements such as chromium and molybdenum need to be added, which leads to increased production costs. 2. Poor component compatibility: The manganese additive has insufficient fusion with the molten steel, which easily leads to component segregation, resulting in uneven internal properties of the steel and defects such as cracks and fractures during subsequent processing; 3. Complex preparation process: Some high-performance manganese additives rely on complex processes such as high-temperature smelting and vacuum purification, which require large equipment investment, have low production efficiency, and are difficult to adapt to large-scale production. 4. Insufficient environmental friendliness: In the traditional process of ferromanganese preparation, the utilization rate of manganese is only 60%-70%, and the discharge of the remaining manganese slag is likely to cause environmental pollution, which does not meet the industry requirements of green metallurgy.

[0003] Therefore, developing a manganese additive that is comprehensive in function, has good component compatibility, and can reduce smelting temperature is of great significance in the field of iron and steel smelting. Summary of the Invention

[0004] The present invention aims to provide a high-strength wear-resistant manganese-based composite additive for steel, its preparation method and application, in order to solve the problems of single function, poor component compatibility, complex preparation process and insufficient environmental protection of existing manganese additives for steel.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a high-strength wear-resistant steel manganese-based composite additive, comprising, by mass percentage, 35-45% low-phosphorus electrolytic manganese powder, 15-20% nano manganese carbide, 10-15% titanium-boron alloy powder, 8-12% silicon-calcium alloy powder, 5-8% calcium aluminate powder, 3-6% calcium oxide powder, and 2-5% nano titanium dioxide. Preferably, as an improvement, the low-phosphorus electrolytic manganese powder has a purity of ≥99.8%, a phosphorus content of ≤0.03%, and a particle size of 50-100μm.

[0006] Preferably, as an improvement, the particle size of nano-manganese carbide is 20-50 nm.

[0007] Preferably, as an improvement, the titanium-boron alloy powder contains 60-70% titanium and 10-15% boron.

[0008] Preferably, as an improvement, the silicon-calcium alloy powder contains 50-60% silicon and 20-30% calcium.

[0009] Preferably, as an improvement, a method for preparing a manganese-based composite additive for high-strength wear-resistant steel involves pre-treating the raw materials, followed by graded pre-mixing, low-temperature sintering, and modification coating.

[0010] Preferably, as an improvement, the graded premixing is a three-stage mixing process: the first stage involves mixing low-phosphorus electrolytic manganese powder, nano-manganese carbide, and nano-titanium dioxide to obtain a manganese-based premix; the second stage involves adding titanium-boron alloy powder and silicon-calcium alloy powder to the manganese-based premix, heating and stirring to obtain a composite premix; and the third stage involves adding calcium aluminate powder and calcium oxide powder to the composite premix, stirring and mixing to obtain a uniform mixture.

[0011] Preferably, as an improvement, the heating rate for low-temperature sintering is 5℃ / min, the sintering temperature is 800-850℃, and the sintering time is 2h.

[0012] Preferably, as an improvement, in the modification and coating stage, the modifier is 5% silane coupling agent KH-550, and the amount of coating agent sprayed is 1-2% of the mass of the primary particles.

[0013] Preferably, as an improvement, the application of a manganese-based composite additive for high-strength wear-resistant steel in steel smelting, wherein the amount of manganese-based composite additive added is 4-6% of the mass of the molten steel.

[0014] The principle and advantages of this solution are as follows: In practical applications, this technical solution comprehensively optimizes the formulation and preparation process of manganese-based additives to address the practical problems existing in the use of existing technologies. Regarding the formulation composition: using low-phosphorus electrolytic manganese powder as the core manganese source, a multi-dimensional synergistic network is built, consisting of "performance enhancement (nano-manganese carbide + titanium-boron alloy powder) + basic function (silicon-calcium alloy powder) + compatibility guarantee (calcium aluminate powder + calcium oxide powder + silane coupling agent) + environmental enhancement (nano-titanium dioxide)". Each component performs its specific function and mutually enhances each other. Specifically, nano-manganese carbide, with its high hardness, forms a diffusely distributed hard phase with the steel matrix, blocking crack propagation during wear; the titanium element in the titanium-boron alloy powder combines with nitrogen and oxygen in the steel to form TiN and TiO2, refining the grains, while the boron element promotes grain boundary strengthening. The two elements form a complementary effect of "hard phase wear resistance + fine grain impact resistance"—avoiding the problems of increased brittleness caused by adding only wear-resistant components or insufficient wear resistance caused by simply refining grains. Furthermore, this technical solution achieves a synergistic improvement in deoxidation and desulfurization and manganese utilization rate through silicon-calcium alloy powder (deoxidation and desulfurization), nano-titanium dioxide (catalytic enhancement), and low-phosphorus electrolytic manganese powder (manganese source). The silicon and calcium in the silicon-calcium alloy powder preferentially react with oxygen and sulfur in the steel to generate low-melting-point silicates and sulfides, reducing the interference of impurities on the reaction of manganese. Nano-titanium dioxide, as a catalytic center, reduces the activation energy of the reaction between manganese and oxygen, promotes the diffusion of manganese into the steel matrix, and reduces the formation of manganese slag. The low-phosphorus electrolytic manganese powder provides a highly active manganese source, forming a stable alloy phase with the catalytic products. The synergy of these three components increases the manganese utilization rate from the traditional 60%-70% to over 90%, while achieving "deep deoxidation and desulfurization + high manganese yield," taking into account both cleanliness and environmental protection. Furthermore, this solution achieves component compatibility through calcium aluminate powder (dispersible compatibility), calcium oxide powder (fluxing), and silane coupling agent (coating modification). Calcium oxide powder lowers the overall melting point of the additive, creating the necessary temperature conditions for the reaction of each component with the molten steel. As an interface modifier, calcium aluminate powder's Al2O3 component forms a transition phase with the oxides in the molten steel, eliminating interfacial tension between components and preventing nanoparticle agglomeration and component segregation. The silane coupling agent KH-550 forms a hydrophilic-oleophilic dual-functional coating on the particle surface, enhancing the wettability of the additive with the molten steel and preventing performance degradation caused by moisture absorption during storage. These three components ensure compatibility across the entire chain from "lowering the reaction threshold - optimizing interfacial bonding - improving storage stability," resulting in a 40% increase in the uniformity of internal steel properties and a reduction in the processing defect rate to below 1%.

[0015] In terms of preparation process, this technical solution abandons the traditional single mixing mode and adopts a three-level gradient mixing (room temperature-heating-cooling) + rotation speed adaptation. According to the mixing sequence of "nano components-alloy components-flux compatible components", combined with temperature and rotation speed gradient adjustment, the nanoparticles are uniformly attached and the alloy components are fully dispersed, avoiding component segregation and performance defects caused by uneven mixing, laying the foundation for subsequent low-temperature sintering and efficient reaction.

[0016] In summary, the beneficial effects of this technical solution are as follows: 1. Synergistic Performance Enhancement: Through the composite design of nano-manganese carbide and titanium-boron alloy powder, the hardness (HRC) of the produced steel product is increased to 55-60, and the impact strength is ≥120J / cm. 2 Its wear resistance is more than 60% higher than that of traditional manganese steel, without the need for additional precious metals, and it combines high strength, high wear resistance and high impact resistance. 2. Significantly improved manganese utilization: The catalytic effect of nano-titanium dioxide combined with the staged mixing process increases the manganese utilization rate to over 90% and reduces manganese slag emissions by 30%, meeting the requirements of green metallurgy. 3. Excellent component compatibility: The coating modification of calcium aluminate powder with silane coupling agent enables the additive to quickly fuse with the molten steel, without component segregation, improving the uniformity of internal properties of steel by 40% and reducing the processing defect rate to below 1%. 4. Low preparation and application costs: The low-temperature sintering process eliminates the need for high-temperature smelting equipment, reducing production energy consumption by 25%; the formula contains no precious metal components, reducing raw material costs by 15%-20%, and it is compatible with existing steelmaking equipment, requiring no production line modifications, making it easy to scale up and promote. 5. Wide adaptability: It can be used in the production of various wear-resistant steels such as ordinary manganese steel and high-strength alloy steel, covering wear-resistant parts scenarios in multiple fields such as mining, engineering, and metallurgy. Detailed Implementation

[0017] The following detailed description provides further details on specific embodiments, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; and the materials, reagents, etc. used are all commercially available.

[0018] Overview of the plan: A high-strength, wear-resistant steel manganese-based composite additive, by weight percentage, comprises 35-45% low-phosphorus electrolytic manganese powder, 15-20% nano-manganese carbide, 10-15% titanium-boron alloy powder, 8-12% silicon-calcium alloy powder, 5-8% calcium aluminate powder, 3-6% calcium oxide powder, and 2-5% nano-titanium dioxide.

[0019] Among them, low-phosphorus electrolytic manganese powder is the main manganese source, with a purity of ≥99.8%, a phosphorus content of ≤0.03%, and a particle size of 50-100μm.

[0020] Nano-manganese carbide has a particle size of 20-50nm, which plays a role in wear resistance and reinforcement. It forms a hard phase with the steel matrix, thereby improving wear resistance.

[0021] Titanium-boron alloy powder contains 60-70% titanium and 10-15% boron, which helps to refine the grains of steel and improve its impact resistance.

[0022] The silicon-calcium alloy powder contains 50-60% silicon and 20-30% calcium, which enhances the deoxidation and desulfurization effects and reduces the impurity content of steel.

[0023] A method for preparing a manganese-based composite additive for high-strength wear-resistant steel includes the following steps: Step 1: Raw material screening and pretreatment: Screen low-phosphorus electrolytic manganese powder, nano manganese carbide, titanium boron alloy powder, silicon-calcium alloy powder, calcium aluminate powder, calcium oxide powder, and nano titanium dioxide to ensure that the purity and particle size of each raw material meet the formula requirements; Place all raw materials in a vacuum drying oven and dry at 80°C for 6 hours to remove moisture and impurities and avoid gas defects in subsequent reactions.

[0024] Step 2, graded premixing: Primary mixing: Low-phosphorus electrolytic manganese powder, nano manganese carbide, and nano titanium dioxide are added to a high-speed mixer at a speed of 1000 r / min and mixed at room temperature for 20 min to make the nano components uniformly adhere to the surface of the manganese powder, thus obtaining a manganese-based premix. Secondary mixing: Add titanium boron alloy powder and silicon-calcium alloy powder to the manganese-based premix, heat to 120℃, rotate at 1500 r / min, and stir for 30 min to achieve uniform dispersion of alloy components and obtain composite premix; Three-stage mixing: Add calcium aluminate powder and calcium oxide powder to the composite premix, cool to 80℃, rotate at 1200 r / min, and stir for 25 min to obtain a uniform mixture.

[0025] Step 3, Low-temperature sintering: The mixture is fed into a rotary kiln, protected by inert gas (nitrogen), and heated at a rate of 5℃ / min to 800-850℃ for 2 hours to achieve initial bonding of components. After sintering, the material is cooled to room temperature by a cooler and then crushed to a particle size of 1-3mm by a crusher to obtain primary particles.

[0026] Step 4, Modification and Coating and Finished Product Preparation: Add the primary particles to the coating machine, spray with 5% KH-550 silane coupling agent (1-2% of the mass of the primary particles), rotate at 300 r / min, and coat for 15 min to improve the particles' resistance to moisture absorption and compatibility with molten steel. After coating, the granules are dried at 100℃ for 2 hours, and then screened to remove impurities and fine powder, resulting in a high-strength wear-resistant manganese-based composite additive for steel.

[0027] A method for applying a manganese-based composite additive for high-strength wear-resistant steel includes the following steps: The above-mentioned manganese-based composite additives are added to the steelmaking converter or electric arc furnace at a mass of 4-6% of the molten steel. The addition is made when the temperature of the molten steel rises to 1500-1550℃ and the initial refining is completed. The stirring rate is 50r / min, and the reaction is held at the temperature for 30min. After refining, casting, and rolling processes, high-strength wear-resistant steel products are obtained, which are suitable for applications such as crusher liners in mining machinery, bucket teeth in excavators, and track plates in engineering machinery.

[0028] Example 1 A high-strength, wear-resistant manganese-based composite additive for steel, comprising, by weight percentage, 40% low-phosphorus electrolytic manganese powder, 18% nano-manganese carbide, 12% titanium-boron alloy powder, 10% silicon-calcium alloy powder, 6% calcium aluminate powder, 4% calcium oxide powder, and 10% nano-titanium dioxide.

[0029] A method for preparing a manganese-based composite additive for high-strength wear-resistant steel includes the following steps: Step 1: Raw material pretreatment: All raw materials are vacuum dried at 80℃ for 6 hours; Step 2, graded premixing: Primary mixing (manganese powder + manganese carbide + titanium dioxide, 1000 r / min, room temperature mixing for 20 min) → Secondary mixing (add titanium boron alloy powder + silicon calcium alloy powder, 120℃, 1500 r / min mixing for 30 min) → Tertiary mixing (add calcium aluminate powder + calcium oxide powder, 80℃, 1200 r / min mixing for 25 min). Step 3, Low-temperature sintering: Sinter at 820℃ for 2 hours under nitrogen protection, and then break into 1-3mm pieces after cooling; Step 4: Coating the finished product: Spray 1.5% KH-550 coupling agent, coat at 300r / min for 15min, and dry at 100℃ for 2h to obtain the finished product.

[0030] Application testing: Wear-resistant steel was prepared by adding 5% of the steel to molten steel at 1550℃ and holding the reaction at that temperature for 30 minutes. Test results: manganese utilization rate 92%, steel hardness HRC58, impact strength 125 J / cm². 2It has 65% better wear resistance than traditional manganese steel and a processing defect rate of 0.8%.

[0031] Example 2 A high-strength wear-resistant steel manganese-based composite additive, by mass percentage, comprises 35% low-phosphorus electrolytic manganese powder, 15% nano manganese carbide, 10% titanium-boron alloy powder, 8% silicon-calcium alloy powder, 5% calcium aluminate powder, 3% calcium oxide powder, and 24% nano titanium dioxide.

[0032] The preparation method is the same as in Example 1.

[0033] Application testing: Sintering temperature 800℃, additive amount 4%, molten steel temperature 1500℃. Test results: manganese utilization rate 90%, steel hardness HRC55, impact strength 120J / cm². 2 Wear resistance is improved by 60%, and the processing defect rate is 0.9%.

[0034] Example 3 A high-strength wear-resistant steel manganese-based composite additive, by mass percentage, comprises 42% low-phosphorus electrolytic manganese powder, 19% nano-manganese carbide, 14% titanium-boron alloy powder, 11% silicon-calcium alloy powder, 7% calcium aluminate powder, 5% calcium oxide powder, and 2% nano-titanium dioxide.

[0035] The preparation method is the same as in Example 1.

[0036] Application testing: Sintering temperature 850℃, additive amount 6%, molten steel temperature 1530℃. Test results: manganese utilization rate 93%, steel hardness HRC60, impact strength 130J / cm². 2 Wear resistance is improved by 70%, and the processing defect rate is 0.7%.

[0037] Comparative Example 1 The difference between this comparative example and Example 1 is that in this comparative example, ordinary manganese powder is used to replace low-phosphorus electrolytic manganese powder in an equal amount.

[0038] Comparative Example 2 The difference between this comparative example and Example 1 is that no nano-titanium dioxide was added in this comparative example.

[0039] Comparative Example 3 The difference between this comparative example and Example 1 is that no calcium silicate powder was added in this comparative example.

[0040] Comparative Example 4 The difference between this comparative example and Example 1 is that in this comparative example, no graded premixing was performed; instead, the mixture was mixed all at once.

[0041] Comparative Example 5 The difference between this comparative example and Example 1 is that step four, the coating treatment, was not performed in this comparative example.

[0042] Comparative Example 6 The difference between this comparative example and Example 1 is that the amount of the composite manganese additive added in this comparative example is 3% of the mass of the molten steel.

[0043] Comparative Example 7 The difference between this comparative example and Example 1 is that the amount of the composite manganese additive added in this comparative example is 8% of the mass of the molten steel.

[0044] Application tests were conducted on the above comparative examples using the same method as in Example 1. Each group underwent three repeated trials, and the test results are shown in Table 1. Table 1

[0045] As shown in Table 1, the performance of Examples 1-3 of this invention is superior to that of the comparative examples in all aspects. Comparative Example 1, which replaced low-phosphorus electrolytic manganese powder with ordinary manganese powder, resulted in a 14% decrease in manganese utilization and a significant reduction in hardness and wear resistance. Comparative Example 2, lacking nano-titanium dioxide, saw its manganese utilization drop to 75%, indicating its indispensable catalytic enhancement effect. Comparative Example 3, without silicon-calcium alloy powder, suffered from insufficient deoxidation and desulfurization, leading to a processing defect rate of 4.5%, highlighting its fundamental functional value. Comparative Example 4, lacking graded premixing, experienced uneven mixing leading to component segregation, resulting in lower manganese utilization and wear resistance compared to the examples. Comparative Example 5, omitting coating treatment, resulted in decreased compatibility between the additive and the molten steel, leading to a processing defect rate of 2.5%. Comparative Example 6 (3%) had insufficient addition, failing to achieve optimal performance. Comparative Example 7 (8%) had excessive addition, failing to further improve performance but instead increasing costs and raising the defect rate, indicating that 4-6% is the optimal addition range.

[0046] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A manganese-based composite additive for high-strength wear-resistant steel, characterized in that: By weight percentage, it includes 35-45% low-phosphorus electrolytic manganese powder, 15-20% nano manganese carbide, 10-15% titanium-boron alloy powder, 8-12% silicon-calcium alloy powder, 5-8% calcium aluminate powder, 3-6% calcium oxide powder, and 2-5% nano titanium dioxide.

2. The high-strength wear-resistant steel manganese-based composite additive according to claim 1, characterized in that: The low-phosphorus electrolytic manganese powder has a purity of ≥99.8%, a phosphorus content of ≤0.03%, and a particle size of 50-100μm.

3. The high-strength wear-resistant steel manganese-based composite additive according to claim 2, characterized in that: The particle size of the nano-manganese carbide is 20-50 nm.

4. The high-strength wear-resistant steel manganese-based composite additive according to claim 3, characterized in that: The titanium-boron alloy powder contains 60-70% titanium and 10-15% boron.

5. The high-strength wear-resistant steel manganese-based composite additive according to claim 4, characterized in that: The silicon-calcium alloy powder contains 50-60% silicon and 20-30% calcium.

6. A method for preparing a manganese-based composite additive for high-strength wear-resistant steel according to any one of claims 1 to 5, characterized in that: The raw materials were pretreated, graded and premixed, and then sintered at low temperature and modified with a coating to obtain the product.

7. The method for preparing a manganese-based composite additive for high-strength wear-resistant steel according to claim 6, characterized in that: The graded premixing is a three-stage mixing process. The first stage involves mixing low-phosphorus electrolytic manganese powder, nano-manganese carbide, and nano-titanium dioxide to obtain a manganese-based premix. The second stage involves adding titanium-boron alloy powder and silicon-calcium alloy powder to the manganese-based premix and heating and stirring to obtain a composite premix. The third stage involves adding calcium aluminate powder and calcium oxide powder to the composite premix and stirring to obtain a uniform mixture.

8. The method for preparing a manganese-based composite additive for high-strength wear-resistant steel according to claim 7, characterized in that: The heating rate for low-temperature sintering is 5℃ / min, the sintering temperature is 800-850℃, and the sintering time is 2h.

9. The method for preparing a manganese-based composite additive for high-strength wear-resistant steel according to claim 8, characterized in that: During the modification and coating stage, the modifier is 5% silane coupling agent KH-550, and the amount of coating agent sprayed is 1-2% of the mass of the primary particles.

10. The application of a high-strength wear-resistant steel manganese-based composite additive according to any one of claims 1 to 5 in steel smelting, characterized in that: The amount of manganese-based composite additive added is 4-6% of the mass of the molten steel.

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