High-strength strain clamp
By adding a mixture of a grain refiner and fluorinated alumina whiskers to aluminum alloy tension clamps, the problem of insufficient tensile strength in aluminum alloy tension clamps is solved by utilizing the grain refinement and second-phase strengthening mechanism, thus achieving the production of high-strength and low-cost tension clamps.
Patent Information
- Application Number
- CN202511346929.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-19
- Publication Date
- 2025-12-12
AI Technical Summary
The existing aluminum alloy tension clamps have insufficient tensile strength, which leads to the need for larger load-bearing cross-sectional dimensions to meet the usage requirements, thus increasing manufacturing costs.
By adding a mixture of a grain refiner and fluorinated alumina whiskers to molten aluminum and then heat-treating it, the tensile strength of the wire clamp body is synergistically improved through grain refinement and a second-phase strengthening mechanism. The grain refiner includes titanium nitride, nano-aluminum powder, and potassium fluoride. The fluorinated alumina whiskers are treated with hydrofluoric acid to generate low-melting-point potassium fluoroaluminate, which reduces interfacial tension, improves the fluidity of the molten aluminum, and enhances the strengthening effect.
This invention achieves high tensile strength in aluminum alloy tension clamps, reduces material usage, lowers manufacturing costs, and improves clamp installation accuracy and stability during use.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of electric power fittings, in particular to a high-strength strain clamp. BACKGROUND
[0002] In the fields of power transmission, electrified railway and photovoltaic outgoing line, strain clamp as a kind of key connecting fittings is usually installed at strain tower, line terminal and corner branch, used for bearing line tension, fixing conductor position and protecting conductor from damage, so as to ensure the safe operation of line.
[0003] At present, most of the materials of strain clamp are ferrous alloy and aluminum alloy. Compared with the disadvantages of ferrous alloy such as large mass, easy corrosion and large electric energy loss, aluminum alloy is favored by the fittings market due to its light weight and non-corrosion. In foreign countries, aluminum alloy strain clamp is widely used, such as aluminum alloy strain clamp is widely used in 220-750kV line in Russia and other countries, However, according to the requirements of general design of power transmission and transformation project, strain clamp should have high tensile strength, such as the tensile strength of ferrous alloy strain clamp should be greater than 350MPa. However, the tensile strength of existing aluminum alloy strain clamp is less than 350MPa. In order to meet the use requirements, the existing aluminum alloy strain clamp needs to have larger bearing cross-sectional size than the ferrous alloy strain clamp, which undoubtedly increases the manufacturing cost. Therefore, it is urgent to develop a high-strength aluminum alloy strain clamp. SUMMARY
[0004] The present application provides a high-strength strain clamp, which solves the problem of low tensile strength of aluminum alloy material in related technologies.
[0005] The technical scheme of the present application is as follows: The present application provides a high-strength strain clamp, which includes a clamp body. After refining, aluminum liquid is added with a mixture of fine grain agent and fluorinated aluminum oxide whisker, cast, and heat treated to obtain the clamp body. In the mixture of fine grain agent and fluorinated aluminum oxide whisker, the fine grain agent includes the following components by weight: titanium nitride 30-50 parts, nano aluminum powder 5-10 parts, and potassium fluoride 10-20 parts. The fluorinated aluminum oxide whisker is obtained by fluoridating aluminum oxide whisker with hydrofluoric acid.
[0006] As a further technical scheme, the preparation method of the fluorinated aluminum oxide whisker is as follows: aluminum oxide whisker is added into hydrofluoric acid solution, reacted, washed, and dried to obtain the fluorinated aluminum oxide whisker.
[0007] As a further technical scheme, the mass-volume ratio of the aluminum oxide whisker and hydrofluoric acid solution is 1g:2-3mL.
[0008] As a further technical solution, the mass fraction of the hydrofluoric acid solution is 30% to 40%.
[0009] As a further technical solution, the temperature of the reaction is 50 to 60 DEG C, and the time is 0.5 to 1 h.
[0010] As a further technical solution, the preparation method of the fine grain agent is: S1, ball milling titanium nitride and nano-aluminum powder to obtain a compound; S2, mixing the compound and potassium fluoride to obtain the fine grain agent.
[0011] As a further technical solution, in step S1, the rotation speed of the ball milling is 200 to 300 rpm, and the time is 1 to 2 h.
[0012] As a further technical solution, the weight ratio of the fine grain agent, fluorinated aluminum oxide whisker and aluminum liquid is 0.04 to 0.06:0.1 to 0.3:100.
[0013] As a further technical solution, the aluminum liquid is composed of the following components in weight percentage: Mg 0.8% to 1.2%, Si 0.4% to 0.8%, Cu 0.15% to 0.4%, Mn≤0.15%, and the rest is Al and inevitable impurities.
[0014] As a further technical solution, the heat treatment is specifically: after solid solution treatment at 500 to 530 DEG C for 5 to 6 h, water quenching to 60 to 70 DEG C, and then aging treatment at 160 to 170 DEG C for 4 to 5 h.
[0015] The beneficial effects of the present application are: In the prior art, fine grain agents and reinforcing phases are often added to improve the tensile strength of the aluminum alloy material of the strain clamp through fine grain strengthening and second phase strengthening mechanisms. However, due to the high melting point and large interfacial tension of the reinforcing phase compared with the aluminum liquid, the addition of the reinforcing phase will cause poor flowability of the aluminum liquid, and the reinforcing phase cannot be uniformly dispersed in the strain clamp body, thereby reducing the reinforcing effect. Unlike the prior art, the present application focuses on the synergistic effect between the fine grain agent component and the reinforcing phase, which avoids the poor reinforcing effect caused by the high melting point of the reinforcing phase. Specifically, after the aluminum oxide whisker is fluorinated by hydrofluoric acid, aluminum fluoride will be generated on the surface of the fluorinated aluminum oxide whisker. The aluminum fluoride on the surface of the fluorinated aluminum oxide whisker will generate low-melting-point potassium fluoroaluminate salt with potassium fluoride in the fine grain agent at high temperature of the aluminum liquid, thereby reducing the interfacial tension between the aluminum oxide whisker and the aluminum liquid, improving the flowability of the aluminum liquid, strengthening the reinforcing effect, and further improving the tensile strength of the aluminum alloy material of the strain clamp. DETAILED DESCRIPTION
[0016] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work, are within the scope of protection of the present application.
[0017] It should be understood that, unless the context clearly indicates otherwise, the terms "comprise", "comprises", "comprising" or "includes" as used herein means the presence of a stated element, but not the exclusion of one or more other elements. In addition, "comprising" and / or "including", as used herein, indicate the presence of the stated shape, number, step, operation, member, element, and / or combination thereof, but do not exclude the presence or addition of one or more other shapes, numbers, operations, elements, and / or combinations thereof.
[0018] The numerical range indicated by "~" in the present application means a numerical range including the numerical range specified before or after the word as the lower limit value and the upper limit value, respectively. When referring to a plurality of numerical values of the upper limit or the lower limit of any numerical range, the range disclosed herein can be understood as a range with any one of the plurality of upper limit values as its upper limit value, and any one of the plurality of lower limit values as its lower limit value.
[0019] A high-strength tension clamp according to an embodiment of the present application will be described in detail below.
[0020] According to an aspect of the present application, a high-strength tension clamp is provided, comprising a clamp body, after refining the aluminum liquid, adding a mixture of fine grain agent and fluorinated aluminum oxide whisker, casting, heat treatment, obtaining the clamp body. In the mixture of fine grain agent and fluorinated aluminum oxide whisker: the fine grain agent comprises the following components by weight: titanium nitride 30-50 parts, nano aluminum powder 5-10 parts, potassium fluoride 10-20 parts, and the fluorinated aluminum oxide whisker is obtained by fluoridating aluminum oxide whisker with hydrofluoric acid.
[0021] In the present application, fine grain agent and fluorinated alumina whisker are added to improve the tensile strength of the body of the wire clamp by fine grain effect and second phase strengthening effect. The fine grain agent can refine the grain, and after the grain is refined, the total area of the grain boundary increases, which helps to hinder the movement of dislocations, so that the tensile strength of the body of the wire clamp is improved. The fluorinated alumina whisker exists in the form of whisker in the body of the wire clamp, and when the body of the wire clamp is subjected to external force, the whisker supports the body of the wire clamp like a skeleton, delaying deformation and fracture, thereby improving the tensile strength of the body of the wire clamp. In addition, after the alumina whisker is fluorinated by hydrofluoric acid, aluminum fluoride is generated on the surface of the alumina whisker. The aluminum fluoride on the surface of the fluorinated alumina whisker and the potassium fluoride in the fine grain agent generate low-melting-point potassium fluoroaluminate salt at high temperature of the aluminum liquid, thereby reducing the interfacial tension between the alumina whisker and the aluminum liquid, improving the fluidity of the aluminum liquid, and enabling the alumina whisker to be uniformly filled in the casting mold under the driving of the aluminum liquid, and finally being uniformly dispersed in the interior of the body of the wire clamp, enhancing the skeleton support effect, and improving the tensile strength of the body of the wire clamp.
[0022] In an embodiment of the present application, the preparation method of the fluorinated alumina whisker is as follows: alumina whisker is added into a hydrofluoric acid solution, reacted, washed, and dried to obtain the fluorinated alumina whisker.
[0023] In an embodiment of the present application, the mass-volume ratio of the alumina whisker and the hydrofluoric acid solution is 1g:2-3mL, for example, it can be 1g:2mL, 1g:2.5mL, 1g:3mL, but is not limited to the listed values, and other values not listed in the range are also applicable.
[0024] In the present application, when the mass-volume ratio of the alumina whisker and the hydrofluoric acid solution is 1g:2-3mL, it can ensure that the hydrofluoric acid solution and the alumina whisker are in sufficient contact and reaction, on the one hand, avoiding excessive reaction caused by too much hydrofluoric acid solution, which destroys the micro-morphology of the alumina whisker and reduces its strengthening effect; on the other hand, avoiding too little hydrofluoric acid solution, which results in insufficient amount of aluminum fluoride on the surface of the alumina whisker, thereby making it difficult to fully play the synergistic effect with potassium fluoride in the fine grain agent.
[0025] In an embodiment of the present application, the mass fraction of the hydrofluoric acid solution is 30%-40%, for example, it can be 30%, 35%, 40%, but is not limited to the listed values, and other values not listed in the range are also applicable.
[0026] In the present application, when the mass fraction of the hydrofluoric acid solution is 30%-40%, it can provide a suitable reaction rate for the fluorination reaction of the alumina whisker, on the one hand, avoiding too low concentration of hydrofluoric acid and too slow reaction rate; on the other hand, avoiding too high concentration of hydrofluoric acid, which makes it difficult to control the reaction process and causes excessive fluorination of the alumina whisker.
[0027] In an embodiment of the present application, the reaction temperature is 50-60 DEG C and the reaction time is 0.5-1 h, for example, the temperature can be 50 DEG C, 55 DEG C or 60 DEG C; the time can be 0.5 h, 0.75 h or 1 h, but is not limited to the listed values, and other values within the range are also applicable.
[0028] In the present application, when the reaction temperature is 50-60 DEG C and the reaction time is 0.5-1 h, the reaction stability of the fluorinated alumina whisker can be improved, on the one hand, to avoid the destruction of the morphology of the alumina whisker due to excessively high temperature or excessively long time; on the other hand, to avoid the uneven thickness of the aluminum fluoride layer due to excessively low temperature or excessively short time.
[0029] In an embodiment of the present application, the diameter of the alumina whisker is 0.5-1 μm and the length is 10-20 μm, for example, the diameter can be 0.5 μm, 0.75 μm or 1 μm; the length can be 10 μm, 15 μm or 20 μm, but is not limited to the listed values, and other values within the range are also applicable.
[0030] In the present application, when the diameter of the alumina whisker is 0.5-1 μm and the length is 10-20 μm, the alumina whisker has an optimal aspect ratio, and is more easily uniformly dispersed in the molten aluminum, to avoid stress concentration due to local agglomeration of the alumina whisker.
[0031] In an embodiment of the present application, the preparation method of the fine-grain agent is as follows: S1, ball-milling titanium nitride and nano-aluminum powder to obtain a composite; S2, mixing the composite and potassium fluoride to obtain the fine-grain agent.
[0032] In the present application, when preparing the fine-grain agent, the nano-aluminum powder with small particle size is uniformly attached to the surface of the titanium nitride by first ball-milling the titanium nitride and the nano-aluminum powder, on the one hand, to provide more active sites on the surface of the titanium nitride, and on the other hand, to improve the wettability of the titanium nitride and the molten aluminum, so that the fine-grain agent can more effectively promote the formation of crystal nucleus when it is used in the molten aluminum, to further improve the tensile strength of the wire clamp body.
[0033] In an embodiment of the present application, the average particle size of the titanium nitride is 1-5 μm and the average particle size of the nano-aluminum powder is 30-50 nm, for example, the average particle size of the titanium nitride can be 1 μm, 3 μm or 5 μm; the average particle size of the nano-aluminum powder can be 30 nm, 40 nm or 50 nm, but is not limited to the listed values, and other values within the range are also applicable.
[0034] In the present application, when the average particle size of the titanium nitride is 1-5 mu m and the average particle size of the nano-aluminum powder is 30-50 nm, the nano-aluminum powder can better adsorb the titanium nitride.
[0035] In one embodiment of the present application, in step S1, the rotation speed of the ball milling is 200-300 rpm, and the time is 1-2 h, for example, the rotation speed can be 200 rpm, 250 rpm, 300 rpm; the time can be 1 h, 1.5 h, 2 h, but not limited to the listed values, other values not listed in this range are also applicable.
[0036] In the present application, when the rotation speed of the ball milling is 200-300 rpm and the time is 1-2 h, on the one hand, the nano-aluminum powder can be adsorbed on the surface of the titanium nitride, and on the other hand, the surface activity of the titanium nitride can be excited through sufficient impact, providing more active sites for the subsequent reaction with the aluminum liquid and further improving the fine-grained effect.
[0037] In one embodiment of the present application, the weight ratio of the fine-grained agent, the fluorinated aluminum oxide whisker and the aluminum liquid is 0.04-0.06:0.1-0.3:100, for example, it can be 0.04:0.1:100, 0.06:0.3:100, but not limited to the listed values, other values not listed in this range are also applicable.
[0038] In the present application, when the weight ratio of the fine-grained agent, the fluorinated aluminum oxide whisker and the aluminum liquid is 0.04-0.06:0.1-0.3:100, the synergistic effect of fine-grained strengthening and second-phase strengthening can be fully utilized, further improving the tensile strength of the wire clamp body.
[0039] In one embodiment of the present application, when the mixture of the fine-grained agent and the fluorinated aluminum oxide whisker is added, the temperature of the aluminum liquid is 740-760℃, for example, it can be 740℃, 750℃, 760℃, but not limited to the listed values, other values not listed in this range are also applicable.
[0040] In one embodiment of the present application, the aluminum liquid is composed of the following components by weight percentage: Mg 0.8%-1.2%, Si 0.4%-0.8%, Cu 0.15%-0.4%, Mn≤0.15%, the rest being Al and unavoidable impurities, for example, the aluminum liquid can be composed of the following components by weight percentage: Mg 0.8%, Si 0.4%, Cu 0.15%, Mn 0.15%, the rest being Al and unavoidable impurities, or the aluminum liquid can be composed of the following components by weight percentage: Mg 1.2%, Si 0.8%, Cu 0.4%, Mn 0.1%, the rest being Al and unavoidable impurities, but not limited to the listed values, other values not listed in this range are also applicable.
[0041] In the present application, the addition of Mg in the molten aluminum can play a role of solid solution strengthening, increase lattice distortion, hinder dislocation movement, and improve the strength of the line clamp body; Si can play a role of precipitation strengthening; Cu can produce aging strengthening effect; and Mn can play a role of purifying the molten aluminum.
[0042] In an embodiment of the present application, the heat treatment is specifically: solid solution treatment at 500-530 DEG C for 5-6h, water quenching to 60-70 DEG C, and then aging treatment at 160-170 DEG C for 4-5h, for example, the heat treatment is specifically: solid solution treatment at 500 DEG C for 6h, water quenching to 70 DEG C, and then aging treatment at 160 DEG C for 5h, but is not limited to the listed values, and other values not listed in the value range are also applicable.
[0043] In the present application, by T6 heat treatment of the line clamp body, on the one hand, the microstructure transformation of the strain clamp in the subsequent use process can be reduced, the dimensional stability of the strain clamp is ensured, and the dimensional installation precision of the strain clamp is ensured; on the other hand, the internal stress of the line clamp body can be released, and the risk of deformation and cracking in the subsequent use process is reduced.
[0044] The high-strength strain clamp in the present application will be described in detail below with reference to examples. The embodiments described below according to the present application can be modified in various forms, and therefore the scope of the present application should not be interpreted as being limited to the embodiments described in detail below. The embodiments are provided to help those skilled in the art more easily understand the present application.
[0045] In the following examples and comparative examples, the average particle size of titanium nitride is 5 μm, the average particle size of nano-aluminum powder is 50 nm, and the diameter of the alumina whisker is 1 μm and the length is 20 μm, unless otherwise specified.
[0046] Example 1 A high-strength strain clamp includes a line clamp body, and the preparation method of the line clamp body is as follows: after refining the molten aluminum, a mixture of a fine grain agent and fluorinated alumina whisker is stirred and mixed uniformly at 750 DEG C, and then cast, and after solid solution treatment at 500 DEG C for 6h, water quenching to 70 DEG C, and then aging treatment at 160 DEG C for 5h, the line clamp body is obtained; The fine grain agent includes the following components in parts by weight: titanium nitride 30 parts, nano-aluminum powder 5 parts, and potassium fluoride 10 parts, and the fine grain agent is obtained by stirring and mixing the components; The preparation method of the fluorinated alumina whisker is as follows: alumina whisker is added into a hydrofluoric acid solution with a mass fraction of 30%, the mass-volume ratio of the alumina whisker and the hydrofluoric acid solution is 1g:2mL, and the reaction is carried out at 50 DEG C for 0.5h, then washed, dried, and the fluorinated alumina whisker is obtained; The weight ratio of the grain refining agent, the fluorinated alumina whisker and the aluminum liquid is 0.04:0.1:100. The aluminum liquid is composed of the following components in percentage by weight: Mg 0.8%, Si 0.4%, Cu 0.15%, Mn 0.15%, the rest being Al and inevitable impurities.
[0047] Embodiment 2 A high-strength strain clamp, comprising a clamp body, the preparation method of the clamp body being: after refining the aluminum liquid, a mixture of a grain refining agent and a fluorinated alumina whisker is stirred and mixed uniformly at 750 DEG C, and then cast, after solution treatment at 530 DEG C for 5h, water quenching to 60 DEG C, and then aging treatment at 170 DEG C for 4h, the clamp body is obtained. The grain refining agent comprises the following components in parts by weight: titanium nitride 50 parts, nano-aluminum powder 10 parts, potassium fluoride 20 parts, and the grain refining agent is obtained by stirring and mixing the components. The preparation method of the fluorinated alumina whisker is: alumina whisker is added into a hydrofluoric acid solution with a mass fraction of 30%, the mass-volume ratio of the alumina whisker and the hydrofluoric acid solution is 1g:3mL, and the reaction is carried out at 60 DEG C for 1h, then the product is washed and dried to obtain the fluorinated alumina whisker. The weight ratio of the grain refining agent, the fluorinated alumina whisker and the aluminum liquid is 0.06:0.3:100. The aluminum liquid is composed of the following components in percentage by weight: Mg 1.2%, Si 0.8%, Cu 0.4%, Mn 0.1%, the rest being Al and inevitable impurities.
[0048] Embodiment 3 The difference between this embodiment and embodiment 2 is only that, in this embodiment, the preparation method of the grain refining agent is: S1, titanium nitride and nano-aluminum powder are ball milled at 250rpm for 1.5h to obtain a composite; S2, the composite and potassium fluoride are mixed uniformly to obtain the grain refining agent.
[0049] Comparative Example 1 The difference between this comparative example and embodiment 1 is only that, in this comparative example, the grain refining agent comprises the following components in parts by weight: titanium nitride 30 parts, nano-aluminum powder 5 parts, sodium chloride 10 parts.
[0050] Comparative Example 2 The difference between this comparative example and embodiment 1 is only that, in this comparative example, the fluorinated alumina whisker is replaced by an equal amount of alumina whisker.
[0051] Comparative Example 3 The difference between the present comparative example and example 1 is that, in the present comparative example, the grain refining agent comprises the following components in parts by weight: titanium nitride 30 parts, nano-aluminum powder 5 parts, sodium chloride 10 parts; the fluorinated alumina whisker is replaced with an equal amount of alumina whisker.
[0052] The tensile strength of the line clamp bodies prepared in examples 1-3 and comparative examples 1-3 is tested according to GB / T 228.1-2021 "Metallic materials-tensile testing-Part 1: Method of test at room temperature", wherein the test rate is 0.008s -1 . The test results are shown in Table 1 below.
[0053] Table 1 Tensile strength test results
[0054] The comparison of example 1 and comparative examples 1-3 shows that the fluorinated alumina whisker can synergize with potassium fluoride in the grain refining agent to strengthen the reinforcing effect, thereby improving the tensile strength of the line clamp body. The comparison of example 3 and example 2 shows that, when preparing the grain refining agent, ball milling titanium nitride and nano-aluminum powder first helps to further improve the tensile strength of the line clamp body.
[0055] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.
Claims
1. A high-strength tension clamp, comprising a clamp body, characterized in that, After refining, a mixture of a fine crystal agent and fluorinated alumina whiskers is added to the molten aluminum, which is then cast and heat-treated to obtain the wire clamp body. The mixture of the fine crystal agent and fluorinated alumina whiskers includes the following components by weight: 30-50 parts titanium nitride, 5-10 parts nano aluminum powder, and 10-20 parts potassium fluoride. The fluorinated alumina whiskers are obtained by fluorinating alumina whiskers with hydrofluoric acid.
2. The high-strength tension clamp according to claim 1, characterized in that, The method for preparing the fluorinated alumina whiskers is as follows: alumina whiskers are added to a hydrofluoric acid solution, reacted, washed, and dried to obtain the fluorinated alumina whiskers.
3. A high-strength tension clamp according to claim 2, characterized in that, The mass-to-volume ratio of the alumina whiskers to the hydrofluoric acid solution is 1g:2~3mL.
4. A high-strength tension clamp according to claim 2, characterized in that, The hydrofluoric acid solution has a mass fraction of 30% to 40%.
5. A high-strength tension clamp according to claim 2, characterized in that, The reaction is carried out at a temperature of 50-60°C for a time of 0.5-1 hour.
6. A high-strength tension clamp according to claim 1, characterized in that, The method for preparing the fine-crystal agent is as follows: S1. Titanium nitride and nano-aluminum powder are ball-milled to obtain a composite. S2. Mix the complex with potassium fluoride to obtain the fine crystal agent.
7. A high-strength tension clamp according to claim 6, characterized in that, In step S1, the ball mill rotates at a speed of 200-300 rpm for 1-2 hours.
8. A high-strength tension clamp according to any one of claims 1 to 7, characterized in that, The weight ratio of the fine crystal agent, fluorinated alumina whiskers and molten aluminum is 0.04~0.06:0.1~0.3:
100.
9. A high-strength tension clamp according to any one of claims 1 to 7, characterized in that, The molten aluminum is composed of the following components by weight percentage: Mg 0.8%~1.2%, Si 0.4%~0.8%, Cu 0.15%~0.4%, Mn≤0.15%, with the remainder being Al and unavoidable impurities.
10. A high-strength tension clamp according to any one of claims 1 to 7, characterized in that, The heat treatment specifically involves: solution treatment at 500~530℃ for 5~6 hours, followed by water quenching to 60~70℃, and then aging treatment at 160~170℃ for 4~5 hours.