Method for manufacturing metal material for dumbbell by utilizing metallurgical solid waste

Abstract

The invention relates to the technical field of powder metallurgy, and provides a method for manufacturing a metal material for a dumbbell by utilizing metallurgical solid waste, which comprises the following steps: S1, uniformly mixing initial raw materials to obtain a mixture; and S2, the mixture is subjected to compression molding and then sintered, and the metal material for the dumbbell is obtained, the initial raw materials comprise the following raw materials in parts by weight: 70-80 parts of pig iron powder, 20-30 parts of wrought iron powder, 0.45-0.55 part of a lubricant, 0.3-0.6 part of modified graphite and 0.4-0.6 part of a cutting agent; wherein the modified graphite is obtained by modifying graphite with 6-hydroxy-2-naphthyl methyl ester. Through the technical scheme, the problem of low hardness of metal materials for dumbbells in related technologies is solved.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy technology, specifically to a method for manufacturing metal materials for dumbbells using metallurgical solid waste. Background Technology

[0002] With the growing awareness of fitness among the general public, the demand for dumbbells has exploded, and their applications are no longer limited to traditional gyms, but have expanded to home fitness, rehabilitation, and other fields. In home settings, lightweight dumbbells have become core equipment for fragmented home training; in the rehabilitation field, customized weight dumbbells are used to assist in the recovery of limb function. The expansion of the market has placed higher demands on the performance and cost of dumbbell materials. However, in stark contrast to the booming dumbbell market, the metallurgical industry has long faced a heavy burden of solid waste disposal. Traditional solid waste disposal methods mainly rely on landfill and stockpiling, which not only require a large amount of land resources but also incur high processing costs.

[0003] Against this backdrop, utilizing metallurgical solid waste in dumbbell manufacturing has become a key solution to both the cost challenges of dumbbell materials and the difficulties in metallurgical solid waste treatment, offering significant cost advantages. From a production process perspective, traditional steel production involves complex steps such as mining, smelting, and rolling, resulting in high energy consumption and costs. In contrast, the recycling of metallurgical solid waste for dumbbell manufacturing eliminates the mining step, and the wastewater and waste gas generated by the recycling process are far less than those of traditional processes, significantly reducing environmental treatment costs and further compressing overall production costs, thus alleviating cost pressures for dumbbell manufacturers.

[0004] However, existing technologies still face challenges in manufacturing dumbbell-shaped metal materials from solid waste. Currently, the industry often incorporates graphite to optimize the mechanical properties of metal materials to meet the hardness requirements of dumbbells. However, graphite is prone to agglomeration within metal materials, resulting in poor dispersion. This uneven dispersion not only prevents graphite from fully exerting its hardness-enhancing effect and achieving the expected hardness increase, but it can also disrupt the uniformity of the material's internal structure. Furthermore, some areas may lack sufficient graphite, leading to insufficient hardness and ultimately negatively impacting the material's overall performance, potentially even posing safety hazards during use.

[0005] Therefore, in order to fully utilize the resource value of metallurgical solid waste and ensure that the performance of dumbbell metal materials meets the standards, it is necessary to propose a new method for manufacturing dumbbell metal materials using metallurgical solid waste, solve the technical pain point of poor graphite dispersibility, and achieve the dual goals of efficient utilization of solid waste resources and optimization of dumbbell material performance. Summary of the Invention

[0006] This invention proposes a method for manufacturing metal materials for dumbbells using metallurgical solid waste, which solves the problem of low hardness in metal materials for dumbbells in related technologies.

[0007] The technical solution of the present invention is as follows: This invention proposes a method for manufacturing metal materials for dumbbells using metallurgical solid waste, comprising the following steps: S1. After mixing the initial raw materials evenly, a mixture is obtained; S2. After pressing the mixture into shape, sinter it to obtain the metal material for dumbbells; The initial raw materials include the following components by weight: 70-80 parts of pig iron powder, 20-30 parts of wrought iron powder, 0.45-0.55 parts of lubricant, 0.3-0.6 parts of modified graphite, and 0.4-0.6 parts of cutting agent; the modified graphite is obtained by modifying graphite with 6-hydroxy-2-naphthyl ester.

[0008] As a further technical solution, the mass of the 6-hydroxy-2-naphthyl ester is 2.7% to 3.7% of the mass of graphite.

[0009] In this invention, a method for manufacturing dumbbell-grade metal materials using metallurgical solid waste is proposed. When modifying graphite, controlling the mass of 6-hydroxy-2-naphthyl ester to 2.7%–3.7% of the graphite mass allows for optimal modification through hydrogen bonding. When the mass of 6-hydroxy-2-naphthyl ester is less than 2.7% of the graphite mass, it cannot adequately cover the graphite surface, resulting in limited improvement in dispersibility. When the mass of 6-hydroxy-2-naphthyl ester is greater than 3.7% of the graphite mass, the excess 6-hydroxy-2-naphthyl ester forms an excessive adsorption layer on the graphite surface, wasting raw materials and causing secondary agglomeration of the modified graphite due to intermolecular forces, thus affecting the modification effect. When the mass of 6-hydroxy-2-naphthyl ester is 2.7%–3.7% of the graphite mass, it can uniformly cover the graphite surface, forming a stable binding layer and improving its dispersibility in the matrix.

[0010] As a further technical solution, the particle size of the graphite is 400~600nm.

[0011] As a further technical solution, the method for preparing the modified graphite includes the following steps: A1. After dispersing graphite in a nitric acid aqueous solution and mixing, the mixture is filtered and washed until the filtrate is neutral. After drying and heat treatment, pretreated graphite is obtained. A2. After dispersing 6-hydroxy-2-naphthyl ester in a solvent, pretreated graphite is added, mixed, and dried to obtain modified graphite.

[0012] As a further technical solution, in step A1, the mass fraction of the nitric acid aqueous solution is 65wt%, and the mass-volume ratio of the graphite to the nitric acid aqueous solution is 1g:8mL.

[0013] As a further technical solution, in step A1, the mixing temperature is 25~35℃ and the time is 1~3h.

[0014] As a further technical solution, in step A1, the temperature of the heat treatment is 380~410℃ and the time is 1~3h.

[0015] As a further technical solution, in step A2, the mixing temperature is 40~45℃ and the mixing time is 2~4h.

[0016] As a further technical solution, in step A2, the mass-to-volume ratio of graphite and anhydrous ethanol is 1g:8mL.

[0017] As a further technical solution, in step A2, the solvent is anhydrous ethanol.

[0018] As a further technical solution, the initial raw materials also include 0.5 to 1 part of wear-resistant reinforcing agent; the wear-resistant reinforcing agent includes potassium hexatitanate and sodium titanate.

[0019] This invention discloses a method for manufacturing metal materials for dumbbells using metallurgical solid waste. A compound of potassium hexatitanate and sodium titanate is used as a wear-resistant reinforcing agent, which can significantly improve the wear resistance of the dumbbell metal materials. Potassium hexatitanate possesses excellent wear-resistant properties, effectively reducing material friction loss and resisting wear erosion; sodium titanate, relying on its layered structure, enhances lubrication through interlayer slippage, further reducing material friction loss. The synergistic effect of the two further improves the wear resistance of the dumbbell metal materials.

[0020] As a further technical solution, the mass ratio of potassium hexatitanate to sodium titanate is 12~15:1.

[0021] As a further technical solution, the lubricant includes one or both of zinc stearate and magnesium stearate.

[0022] In this invention, the method for manufacturing metal materials for dumbbells using metallurgical solid waste involves the addition of lubricants such as zinc stearate and magnesium stearate, which reduces friction and ensures proper molding. During the powder mixing stage, the lubricant adheres to the surface of the metal powder particles, reducing inter-particle friction and allowing for more uniform dispersion of powders with different compositions, thus preventing localized uneven distribution. Furthermore, during the pressing and molding process, the lubricant forms a lubricating film between the powder particles and the mold wall, reducing wear on the mold and decreasing the pressing pressure. This makes the blank easier to shape and prevents defects such as cracking and deformation when the blank is removed from the mold.

[0023] As a further technical solution, the cutting agent is manganese sulfide.

[0024] In this invention, the method for manufacturing metal materials for dumbbells using metallurgical solid waste incorporates manganese sulfide as a cutting agent, which improves processing convenience and finished product quality. As a typical solid lubricant, manganese sulfide reduces the material's cutting resistance and coefficient of friction, not only reducing wear and extending the service life of the dumbbell metal materials but also making cutting and grinding processes smoother. This effectively prevents problems such as chipping and burrs during processing, improving processing efficiency and reducing production costs. Furthermore, the addition of manganese sulfide optimizes processing precision, resulting in greater dimensional stability and a higher surface finish in the final product, better meeting the aesthetic requirements of dumbbells.

[0025] As a further technical solution, the pressing molding involves loading the mixture into a mold and cold pressing it under a pressure of 580~620MPa.

[0026] This invention utilizes a cold-pressing process to manufacture metal materials for dumbbells from metallurgical solid waste. Compared to casting, cold pressing offers significant advantages in cost reduction and process simplification. Unlike casting, it eliminates the complex steps of high-temperature melting and pouring, saving on smelting equipment investment and fuel consumption, thus greatly conserving energy. The process also eliminates metal melting and solidification, shortening the production cycle and reducing equipment maintenance and labor costs. Furthermore, cold pressing allows for more efficient use of raw material powder, reducing waste and further lowering raw material loss costs. Overall, cost reduction is achieved across the entire process, from equipment and energy to labor and raw materials.

[0027] As a further technical solution, the sintering temperature is 1050~1100℃ and the time is 0.5~1.5h.

[0028] The working principle and beneficial effects of this invention are as follows: In this invention, a method for manufacturing dumbbell metal materials using metallurgical solid waste is disclosed. By adding 6-hydroxy-2-naphthyl ester to modify graphite, the hardness of the dumbbell metal material is significantly improved. Graphite has a relatively high surface energy and is prone to agglomeration during mixing. To reduce the impact of agglomeration on the hardness improvement of the dumbbell metal material, 6-hydroxy-2-naphthyl ester is used to modify the graphite, forming a uniform coating layer on the graphite surface. This improves the uniformity of graphite dispersion in the powder, thereby effectively enhancing the hardness of the dumbbell metal material. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] In the following examples and comparative examples, pig iron powder was purchased from Lingshou County Dekai Mineral Products Processing Plant; wrought iron powder was purchased from Anyang Rongjiang Materials Co., Ltd.; and graphite with a particle size of 500nm was purchased from Shanghai Naio Nanotechnology Co., Ltd.

[0031] Example 1 A method for manufacturing dumbbell metal materials using metallurgical solid waste includes the following steps: mixing 70 parts of pig iron powder, 20 parts of wrought iron powder, 0.45 parts of magnesium stearate, 0.3 parts of modified graphite, 0.4 parts of manganese sulfide, and 0.5 parts of wear-resistant reinforcing agent evenly to obtain a mixture; loading the mixture into a mold, cold-pressing it under a pressure of 600 MPa, and then sintering it at 1180℃ for 1 hour to obtain the metal material for manufacturing dumbbells using metallurgical solid waste; wherein the wear-resistant reinforcing agent is potassium hexatitanate; The preparation method of modified graphite includes the following steps: A1. Graphite was dispersed in a 65wt% nitric acid aqueous solution, mixed at 30°C for 2 hours, filtered and washed until the filtrate was neutral, dried, and then heat-treated at 400°C for 2 hours to obtain pretreated graphite; wherein the mass-volume ratio of graphite to nitric acid aqueous solution was 1g:8mL. A2. 6-hydroxy-2-naphthyl ester was dispersed in anhydrous ethanol, and then pretreated graphite was added. The mixture was mixed at 40°C for 3 hours and dried to obtain modified graphite. The mass of 6-hydroxy-2-naphthyl ester was 2.7% of the mass of graphite, and the mass-volume ratio of graphite to anhydrous ethanol was 1 g: 8 mL.

[0032] Example 2 Compared with Example 1, the only difference in Example 2 is that this example provides a method for manufacturing metal materials for dumbbells using metallurgical solid waste, which includes the following steps: mixing 75 parts of pig iron powder, 25 parts of wrought iron powder, 0.5 parts of zinc stearate, 0.5 parts of modified graphite, 0.5 parts of manganese sulfide, and 0.8 parts of wear-resistant reinforcing agent evenly, obtaining a mixture, cold pressing it into shape, and sintering it at 1180°C to obtain metal materials for manufacturing dumbbells using metallurgical solid waste; wherein, the wear-resistant reinforcing agent is potassium hexatitanate.

[0033] Example 3 Compared with Example 1, the only difference in Example 3 is that this example provides a method for manufacturing metal materials for dumbbells using metallurgical solid waste, which includes the following steps: mixing 80 parts of pig iron powder, 30 parts of wrought iron powder, 0.55 parts of zinc stearate, 0.6 parts of modified graphite, 0.6 parts of manganese sulfide, and 1 part of wear-resistant reinforcing agent evenly, obtaining a mixture, cold pressing it into shape, and sintering it at 1180℃ to obtain metal materials for dumbbells; wherein, the wear-resistant reinforcing agent is potassium hexatitanate.

[0034] Example 4 Compared with Example 1, the only difference in Example 4 is that in the preparation method of modified graphite in this example, the mass of 6-hydroxy-2-naphthyl ester is 3.2% of the mass of graphite.

[0035] Example 5 Compared with Example 1, the only difference in Example 5 is that in the preparation method of modified graphite in this example, the mass of 6-hydroxy-2-naphthyl ester is 3.7% of the mass of graphite.

[0036] Example 6 Compared with Example 1, the only difference in Example 6 is that the wear-resistant reinforcing agent in this example is composed of potassium hexatitanate and sodium titanate in a mass ratio of 12:1.

[0037] Example 7 Compared with Example 1, the only difference in Example 7 is that the wear-resistant reinforcing agent in this example is composed of potassium hexatitanate and sodium titanate in a mass ratio of 13:1.

[0038] Example 8 Compared with Example 1, the only difference in Example 8 is that the wear-resistant reinforcing agent in this example is composed of potassium hexatitanate and sodium titanate in a mass ratio of 15:1.

[0039] Example 9 Compared with Example 1, the only difference in Example 8 is that the wear-resistant reinforcing agent in this example is sodium titanate.

[0040] Comparative Example 1 Compared with Example 1, the only difference in Comparative Example 1 is that the modified graphite was replaced with an equal amount of graphite.

[0041] The dumbbells prepared in Examples 1-9 and Comparative Example 1 were tested with metallic materials according to the following method: 1. Hardness test: The hardness of the technical material for dumbbells is tested according to the test method specified in standard GB / T 230.1-2018 "Metallic materials Rockwell hardness test - Part 1: Test method"; 2. Wear resistance test: Wear amount: The test is carried out in accordance with the test method specified in standard GB / T34501-2017 "Test method for wear resistance of cemented carbide". The rotating wheel is a steel wheel with a load of 130N, a rotation speed of 1m / s, an abrasive flow rate through the contact surface of 150g / min, and a test time of 20min.

[0042] The test results are shown in Tables 1 and 2: Table 1. Hardness test results of metal materials used in dumbbells

[0043] As shown in Table 1, the comparison between Examples 1-5 and Comparative Example 1 demonstrates that the addition of 6-hydroxy-2-naphthyl ester modified graphite can significantly improve the hardness of the metal material for dumbbells of the present invention.

[0044] Table 2. Test results of wear resistance of metallic materials used in dumbbells

[0045] As shown in Table 2, the comparison of Examples 1, 6-9 indicates that the addition of the wear-resistant reinforcing agent composed of potassium hexatitanate and sodium titanate can further improve the wear resistance of the metal material for dumbbells of the present invention.

[0046] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for manufacturing metal materials for dumbbells using metallurgical solid waste, characterized in that, Includes the following steps: S1. After mixing the initial raw materials evenly, a mixture is obtained; S2. After pressing the mixture into shape, sinter it to obtain the metal material for dumbbells; The initial raw materials include the following components by weight: 70-80 parts of pig iron powder, 20-30 parts of wrought iron powder, 0.45-0.55 parts of lubricant, 0.3-0.6 parts of modified graphite, and 0.4-0.6 parts of cutting agent; the modified graphite is obtained by modifying graphite with 6-hydroxy-2-naphthyl ester.

2. The method for manufacturing metal materials for dumbbells using metallurgical solid waste according to claim 1, characterized in that, The mass of the 6-hydroxy-2-naphthyl methyl ester is 2.7% to 3.7% of the mass of graphite.

3. The method for manufacturing metal materials for dumbbells using metallurgical solid waste according to claim 1, characterized in that, The method for preparing the modified graphite includes the following steps: A1. After dispersing graphite in an aqueous nitric acid solution and mixing, the mixture is filtered and washed until the filtrate is neutral. After drying and heat treatment, pretreated graphite is obtained. A2. After dispersing 6-hydroxy-2-naphthyl ester in a solvent, pretreated graphite is added, mixed, and dried to obtain modified graphite.

4. The method for manufacturing metal materials for dumbbells using metallurgical solid waste according to claim 1, characterized in that, The graphite has a particle size of 400~600nm.

5. A method for manufacturing metal materials for dumbbells using metallurgical solid waste according to claim 3, characterized in that, In step A2, the mixing temperature is 40~45℃ and the mixing time is 2~4h.

6. The method for manufacturing metal materials for dumbbells using metallurgical solid waste according to claim 1, characterized in that, The initial raw materials also include 0.5 to 1 part of wear-resistant reinforcing agent; the wear-resistant reinforcing agent includes potassium hexatitanate and sodium titanate.

7. A method for manufacturing metal materials for dumbbells using metallurgical solid waste according to claim 6, characterized in that, The mass ratio of potassium hexatitanate to sodium titanate is 12~15:

1.

8. The method for manufacturing metal materials for dumbbells using metallurgical solid waste according to claim 1, characterized in that, The lubricant includes one or both of zinc stearate and magnesium stearate.

9. A method for manufacturing metal materials for dumbbells using metallurgical solid waste according to claim 1, characterized in that, The pressing process involves loading the mixture into a mold and cold-pressing it under a pressure of 580~620MPa.

10. A method for manufacturing metal materials for dumbbells using metallurgical solid waste according to claim 1, characterized in that, The sintering temperature is 1050~1100℃ and the time is 0.5~1.5h.

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