An anti-fatigue aluminum alloy wire and a preparation method thereof

Abstract

The application discloses an anti-fatigue aluminum alloy wire and a preparation method thereof. The anti-fatigue aluminum alloy wire comprises the following components in percentage by mass: Mg: 0.27-0.45%, Si: 0.27-0.5%, Fe: 0.1-0.15%, Y: 0.1-0.3%, La: 0.01-0.05%, B: 0.001-0.05%, and the balance of Al. The components further comprise inevitable other impurity elements, the content of each of the inevitable impurity elements is less than or equal to 0.005%, and the total content of the inevitable other impurity elements is less than or equal to 0.02%. The anti-fatigue aluminum alloy wire can realize grain refinement and grain boundary strengthening of the material, improve the anti-fatigue performance of the material, and improve the grain boundary structure and mechanical properties of the material by controlling parameters such as deformation temperature, deformation speed and deformation ratio of extrusion and drawing. The anti-fatigue performance of the prepared aluminum alloy wire is improved by 20-50% compared to the existing top level in the industry, and the aluminum alloy wire is the only product in China that has passed 3000 million times of fatigue examination and verification under the condition of extreme running tension.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aluminum materials, and particularly relates to an anti-fatigue aluminum alloy wire and a preparation method thereof. BACKGROUND

[0002] In a power transmission line, the aeolian vibration is the main cause of line damage. Especially in the open plain area, the overhead power transmission conductor is easily affected by the constant direction and stable wind speed (0.5-10 m / s) of the aeolian wind, the Karman vortex is generated on the leeward side of the power transmission conductor alternately upwards and downwards, the alternating stress is caused to act on the power transmission conductor, the vertical vibration of the conductor is caused, the small amplitude relative sliding displacement of the contact surface is caused under the action of the alternating stress, the friction sliding of the contact surface causes the wear of the conductor surface, the repeated tangential displacement causes the decrease of the fatigue strength of the conductor, the generation and expansion of the fatigue crack of the conductor are promoted, and finally the fatigue fracture of the conductor is caused. And the characteristics of high frequency and small amplitude are not as obvious as the damage of the line galloping, and have certain concealment, and sometimes it is difficult to find from the outer surface of the power transmission conductor, and the potential danger is brought to the safe operation of the power transmission line.

[0003] In the preparation process, the addition of the refiner can play the role of refining the grains in the alloy, the grain size is reduced, the small grains can improve the strength and toughness of the material, reduce the dislocation slip of the grain boundary, and thus improve the anti-fatigue performance of the material, at the same time, by adjusting the process parameters in the preparation process, the grain size, grain boundary structure and precipitate phase morphology of the material can be changed, and thus the anti-fatigue characteristics of the material are affected. For example, by controlling the deformation temperature, deformation speed and deformation ratio and other parameters of extrusion and drawing, the grain refinement and grain boundary strengthening of the material can be realized, and the anti-fatigue performance of the material is improved. In addition, the appropriate heat treatment process can further improve the grain boundary structure and mechanical properties of the material. SUMMARY

[0004] This section is intended to summarize some aspects of the embodiments of the application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, the abstract and the title, and such simplifications or omissions cannot be used to limit the scope of the application.

[0005] In view of the above and / or problems existing in the prior art, the present application is proposed.

[0006] Therefore, the purpose of the present application is to overcome the deficiencies in the prior art, and to provide an anti-fatigue aluminum alloy wire.

[0007] To solve the above technical problems, the application provides the following technical scheme: ingredients include, by mass percentage, Mg: 0.27-0.45%, Si: 0.27-0.5%, Fe: 0.1-0.15%, Y: 0.1-0.3%, La: 0.01-0.05%, B: 0.001-0.05%, and the balance is Al.

[0008] The ingredients further include inevitable other impurity elements, and the content of each of the inevitable impurity elements is ≤0.005%, and the total content of the inevitable other impurity elements is ≤0.02%.

[0009] As a preferred scheme of the anti-fatigue aluminum alloy wire, the anti-fatigue aluminum alloy wire has a tensile strength ≥325 MPa, an electrical conductivity ≥52.5% IACS, and an anti-fatigue frequency ≥30 million times.

[0010] Another object of the application is to provide a preparation method of the anti-fatigue aluminum alloy wire.

[0011] As a preferred scheme of the preparation method of the anti-fatigue aluminum alloy wire, the preparation method comprises the following steps:

[0012] 99.7% aluminum ingots, aluminum silicon alloy, and aluminum iron alloy are heated and melted, and magnesium ingots are added for fully stirring and uniformity.

[0013] The aluminum liquid is fully stirred and refined, and then is subjected to static treatment.

[0014] After the online refining of the melt, a refiner is added, and then the melt is subjected to continuous casting and rolling to obtain an aluminum alloy rod material with a diameter of 9.5 mm, the rod material is subjected to drawing processing to obtain a wire blank with a diameter of 5-6 mm.

[0015] After the annealing treatment and secondary drawing of the alloy wire blank, solid solution treatment and aging treatment are performed to obtain a finished wire material with a diameter of 2.0-4.0 mm.

[0016] As a preferred scheme of the preparation method of the anti-fatigue aluminum alloy wire, the in-furnace refining process is to refine the melt in the furnace by using high-purity nitrogen and a granular refiner for 10-15 minutes.

[0017] As a preferred scheme of the preparation method of the anti-fatigue aluminum alloy wire, after the aluminum liquid is fully stirred and refined, the surface dross is completely cleaned, the temperature is adjusted to 720±10°C, and the aluminum liquid is subjected to static treatment for 30-40 minutes.

[0018] As a preferred scheme of the preparation method of the anti-fatigue aluminum alloy wire, the on-line refining comprises two parts of on-line degassing and electromagnetic purification of impurities, the on-line degassing adopts a rotary blowing degassing box, and high-purity nitrogen is used as the degassing medium, and the nozzle rotating speed is 400-500 r / min.

[0019] As a preferred scheme of the preparation method of the anti-fatigue aluminum alloy wire, the refining agent is an aluminum titanium boron rod, and the addition amount of the refining agent in the melt is 0.05-0.15%.

[0020] As a preferred scheme of the preparation method of the anti-fatigue aluminum alloy wire, the cross-sectional area of the casting blank in the continuous casting and rolling process is 2400 mm 2 , the casting temperature is 710±10℃, the casting speed is 8-12 m / min, the cooling water temperature is 15-40℃, and the cooling water pressure is 0.35-0.5 MPa.

[0021] The rolling temperature is controlled to be 500-530℃.

[0022] As a preferred scheme of the preparation method of the anti-fatigue aluminum alloy wire, the heating temperature in the annealing process is 400-450℃, and the holding time is 2-3 h.

[0023] As a preferred scheme of the preparation method of the anti-fatigue aluminum alloy wire, the heating temperature of the solid solution treatment is 450-500℃, the holding time is 2-3 h, and then quenching is performed to form a supersaturated solid solution, the aging treatment temperature of the supersaturated solid solution is 150-180℃, and the holding time is 5-10 h.

[0024] The anti-fatigue aluminum alloy wire prepared by the preparation method has the following advantages:

[0025] By controlling the deformation temperature, deformation speed and deformation ratio and other parameters of extrusion and drawing, the grain refinement and grain boundary strengthening of the material can be realized, the anti-fatigue performance of the material is improved, and the grain boundary structure and mechanical properties of the material are improved by using a suitable heat treatment process. The anti-fatigue performance of the aluminum alloy wire prepared by the preparation method is improved by 20-50% compared with the existing top level in the industry, and the aluminum alloy wire is the only product in China that has passed the 3000 million fatigue test under the condition of extreme running tension. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned purposes, characteristics and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the description examples.

[0027] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details set forth in this description. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present application.

[0028] It is also noted that, as used herein, "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the application. The appearances of the phrase "in one embodiment" or "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

[0029] The method for determining the tensile strength of the aluminum alloy wire in the present application refers to ASTM standard E8 / E8M;

[0030] The method for determining the electrical conductivity refers to ASTM standard B193;

[0031] The method for determining the fatigue resistance is the single-point fatigue test method.

[0032] The raw materials used in the present application are commercially available in the art without special instructions.

[0033] Example 1

[0034] The present embodiment provides an anti-fatigue aluminum alloy wire and a preparation method thereof, in particular to:

[0035] 1) Prepare the raw materials according to the following mass ratio of components:

[0036] Mg: 0.4%, Si: 0.4%, Fe: 0.15%, Y: 0.3%, La: 0.5%, B: 0.005%, and the rest is Al and unavoidable impurity elements;

[0037] 2) Add 99.7% aluminum ingots, aluminum-silicon alloy, and aluminum-iron alloy into a smelting furnace for heating and melting, add magnesium ingots into the aluminum liquid for sufficient stirring and uniformity, take samples for spectral analysis, and control the melt composition within the required range;

[0038] 3) Transfer the aluminum liquid to a tilting holding furnace, start the electromagnetic stirring device at the bottom of the furnace to fully stir the melt, adjust the melt temperature to 750°C, refine the melt in the furnace with high-purity nitrogen gas and granular refining agent for 15 minutes, then completely clean the surface dross of the aluminum melt, and adjust the temperature to 720°C for 40 minutes of static treatment;

[0039] 4) using a rotary spray degassing tank with high-purity nitrogen as the degassing medium, the nozzle rotation speed is 450 r / min; using a metal melt electromagnetic purification device, under the action of the electromagnetic field, the aluminum melt has a tendency to deviate to one side, expelling non-metallic slag to the other side, so that the non-metallic slag is aggregated and pushed to the adsorbed ceramic tube separator, thereby realizing the purification of the aluminum melt, and effectively removing particles of 1-10 μm and above;

[0040] 5) adding aluminum-titanium-boron rods for grain refinement treatment;

[0041] 6) using a wheel-type crystallizer for continuous casting, the casting area of the casting blank is 2400 mm 2 , the casting temperature is 710℃, the casting speed is 10 m / min, the cooling water temperature is 30℃, the cooling water pressure is 0.4 MPa, after the casting blank is separated from the crystallization wheel, it is sent to a two-roller continuous rolling mill set through a lead-in device, and the rolling-in temperature is controlled at 520℃, and after rolling, an aluminum alloy rod material with a diameter of 9.5 mm is obtained, and the rod material is wound after online cooling;

[0042] 7) using a six-connection drawing device to draw the rod material to obtain a wire blank with a diameter of 5.5 mm.

[0043] 8) solid solution treatment of the alloy wire blank, heating temperature is 420℃, holding time is 2h;

[0044] 9) secondary drawing of the alloy wire blank after solid solution treatment on a sliding type drawing machine to obtain a wire material with a diameter of 3.0 mm;

[0045] 10) solid solution treatment of the drawn alloy wire material, heating temperature is 450℃, holding for 2h, then quenching to form a supersaturated solid solution, then aging treatment of the supersaturated solid solution, aging temperature is 160℃, holding time is 8h, to obtain the anti-fatigue aluminum alloy wire.

[0046] Example 2

[0047] The difference between this embodiment and Example 1 is that the mass ratio of the raw materials is adjusted, specifically:

[0048] Mg: 0.35%, Si: 0.35%, Fe: 0.13%, Y: 0.2%, La: 0.03%, B: 0.004%, the rest is Al and unavoidable impurity elements;

[0049] The rest of the preparation method is the same as that of Example 1, and the anti-fatigue aluminum alloy wire of this embodiment is obtained.

[0050] Example 3

[0051] The difference between this embodiment and Example 1 is that the mass ratio of the raw materials is adjusted, specifically:

[0052] Mg: 0.3%, Si: 0.3%, Fe: 0.12%, Y: 0.15%, La: 0.02%, B: 0.003%, the rest is Al and inevitable impurity elements;

[0053] The rest of the preparation method is the same as that of Example 1, and the anti-fatigue aluminum alloy wire of the present example is obtained.

[0054] The anti-fatigue aluminum alloy wires in Examples 1-3 of the present application were subjected to performance testing, and the results are shown in Table 1.

[0055] Table 1 Performance test results of aluminum alloy wires prepared under different aging conditions

[0056]

[0057] From the observation of Table 1, it can be seen that:

[0058] The anti-fatigue aluminum alloy wires prepared in Examples 1-3 have a tensile strength ≥ 325 MPa, an electrical conductivity ≥ 52.5% IACS, and an anti-fatigue number ≥ 30 million times.

[0059] This is because aluminum titanium boron rods are used as refiners, and aluminum titanium boron rods can play a role in refining the grains in the alloy, reducing the grain size. Small grains can improve the strength and toughness of the material, reduce the dislocation slip of the grain boundary, and at the same time increase the area of the grain boundary and the strengthening effect of the grain boundary. Grain boundary strengthening can effectively hinder the slip and expansion of dislocations, improving the fatigue strength of the material. When subjected to external loads, small grains can better absorb and disperse stress, reduce stress concentration, and reduce the tendency of the material to break. At the same time, the solid solution is aged at an aging temperature of 160°C for 8h, which further strengthens the material by forming precipitates, fills the gaps and defects in the grain boundary and intragranular, reduces the deformation and creep of the material, and thus improves the dimensional stability of the material.

[0060] Comparative Example 1

[0061] This comparative example is based on Example 1, except that the aluminum titanium boron rod in step 5) is replaced with an aluminum titanium carbon rod, and the rest of the preparation method is the same as that of Example 1, obtaining the anti-fatigue aluminum alloy wire of the present comparative example.

[0062] Comparative Example 2

[0063] This comparative example is based on Example 1, except that the aluminum titanium boron rod in step 5) is replaced with an aluminum titanium silicon rod, and the rest of the preparation method is the same as that of Example 1, obtaining the anti-fatigue aluminum alloy wire of the present comparative example.

[0064] The anti-fatigue aluminum alloy wires in Comparative Examples 1-2 were subjected to performance testing, and compared with Example 1, and the results are shown in Table 2.

[0065] Table 2 Performance testing results of aluminum alloy wires prepared under different aging conditions

[0066]

[0067] According to the comparison results in Table 2, it can be seen that the tensile strength of the aluminum alloy wires prepared in Comparative Examples 1 and 2 during the testing process is far less than 325 MPa, and the electrical conductivity and anti-fatigue times are also significantly reduced compared with Example 1. This is because the precipitated phase formed by the aluminum-titanium-carbon rod and the aluminum-titanium-silicon rod in the aluminum alloy is relatively large, the refining effect is relatively weak, the strengthening effect on the material and the improvement of the anti-fatigue performance are limited, and in some specific conditions, it may react with other elements, resulting in instability of the refining effect.

[0068] Comparative Example 3

[0069] This comparative example is based on Example 1, except that the aging treatment temperature in step 9) is changed to 140°C, and the rest of the preparation method is the same as Example 1, to obtain the anti-fatigue aluminum alloy wire of this comparative example.

[0070] Comparative Example 4

[0071] This comparative example is based on Example 1, except that the aging treatment temperature in step 9) is changed to 190°C, and the rest of the preparation method is the same as Example 1, to obtain the anti-fatigue aluminum alloy wire of this comparative example.

[0072] Comparative Example 5

[0073] This comparative example is based on Example 1, except that the aging treatment holding time in step 9) is changed to 4h, and the rest of the preparation method is the same as Example 1, to obtain the anti-fatigue aluminum alloy wire of this comparative example.

[0074] Comparative Example 6

[0075] This comparative example is based on Example 1, except that the aging treatment holding time in step 9) is changed to 11h, and the rest of the preparation method is the same as Example 1, to obtain the anti-fatigue aluminum alloy wire of this comparative example.

[0076] The anti-fatigue aluminum alloy wires in Comparative Examples 3-6 were subjected to performance testing, and compared with Example 1, and the results are shown in Table 3.

[0077] Table 3 Performance testing results of aluminum alloy wires prepared under different aging conditions

[0078]

[0079] According to the comparison results in Table 3, it can be seen that the aluminum alloy wire prepared under the condition of aging temperature of 160℃ and holding time of 8h has the optimal comprehensive performance, mainly because of the aging treatment, the β” and β’ metastable strengthening phase containing Mg and Si alloying elements are precipitated in the alloy, so that the wire obtains higher strength and conductivity.

[0080] When the aging temperature is too high or the holding time is too long, the size and quantity of the precipitated phase are too much, which causes the aggregation and coarsening of the precipitated phase, so that the strength and hardness of the material are reduced, and the fracture and embrittlement phenomenon in the grain boundary and the grain interior are caused, the toughness and plasticity of the material are reduced, the corrosion medium is more easily to invade the interior of the material, so that the corrosion resistance of the material is reduced, and the deformation and creep of the material are caused, the size changes and distortion are caused, the size stability affects the precision and reliability of the material, and the service life of the material is reduced.

[0081] When the aging temperature is too low or the holding time is too short, the formation of the precipitated phase is not complete, the expected strengthening effect cannot be achieved, the dislocation locking and sliding are limited, the strength and hardness of the material cannot be effectively improved, the toughness and plasticity of the material are also limited, and the voids and defects in the grain boundary and the grain interior cannot be fully filled, so that the size stability of the material is affected, and the service life of the material is reduced, therefore, the appropriate aging treatment condition needs to be selected, so as to improve the fatigue resistance and mechanical properties of the material.

[0082] In summary, using aluminum-titanium-boron rod as a refiner, and cooperating with the aging temperature of 160℃ and the holding time of 8h for the aging treatment of the solid solution, the fatigue resistance and corrosion resistance of the fatigue resistance aluminum alloy wire can be significantly improved, and a plurality of high-strength fatigue resistance aluminum alloy single wires with matched strength and conductivity, such as 320MPa / 53%IACS, 265MPa / 57%IACS and 230MPa / 59%IACS, are prepared. Combined with special high-strength steel core, a special large-span overhead conductor is manufactured, and an all-aluminum alloy energy-saving conductor is produced as an aluminum alloy reinforcing core. It can be used in the ultra-high voltage engineering such as “southeast of Shanxi”, “Wan Dian Dong Song” and “Huai Shang line”, and solves the urgent need of the national power grid construction.

[0083] It should be noted that the above examples are only used to illustrate the technical solutions of the present application, not to limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, which should be covered in the scope of the claims of the present application.

Claims

1. A fatigue-resistant aluminum alloy wire, characterized in that: Its composition by mass percentage includes: Mg: 0.27~0.45%, Si: 0.27~0.5%, Fe: 0.1~0.15%, Y: 0.1~0.3%, La: 0.01~0.05%, B: 0.001~0.05%, with the balance being Al; The fatigue-resistant aluminum alloy wire has a tensile strength ≥325MPa, conductivity ≥52.5%IACS, and fatigue resistance ≥30 million cycles; The method for preparing the fatigue-resistant aluminum alloy wire includes the following steps: 99.7% aluminum ingots, aluminum-silicon alloys, and aluminum-iron alloys are heated and melted, and magnesium ingots are added and stirred thoroughly. The molten aluminum is thoroughly stirred and refined, and then allowed to stand. After online refining of the melt, a refining agent is added, followed by continuous casting and rolling to obtain an aluminum alloy rod with a diameter of 9.5 mm. The rod is then drawn to obtain a wire rod with a diameter of 5-6 mm. After annealing and secondary drawing, the alloy wire blank is subjected to solution treatment and aging treatment to obtain finished wire with a diameter of 2.0~4.0mm. The refining agent is an aluminum-titanium-boron rod, and the amount of the refining agent added relative to the melt is 0.05~0.15%; The aging treatment temperature for supersaturated solid solutions is 150~180℃, and the holding time is 5~10h.

2. The fatigue-resistant aluminum alloy wire as described in claim 1, characterized in that: After thoroughly stirring and refining the molten aluminum, the surface slag is completely removed, and the temperature is adjusted to 720±10℃ and left to stand for 30~40 minutes.

3. The fatigue-resistant aluminum alloy wire as described in claim 1, characterized in that: The online refining process includes two parts: online degassing and electromagnetic purification. The online degassing uses a rotary jet degassing box with high-purity nitrogen as the degassing medium and the nozzle speed is 400~500 r / min.

4. The fatigue-resistant aluminum alloy wire as described in claim 1, characterized in that: The cross-sectional area of ​​the billet in the continuous casting and rolling process is 2400 mm². 2 The casting temperature is 710±10℃, the casting speed is 8~12m / min, the cooling water temperature is 15~40℃, and the cooling water pressure is 0.35~0.5MPa; the rolling temperature is controlled at 500~530℃.

5. The fatigue-resistant aluminum alloy wire as described in claim 1, characterized in that: The annealing process involves heating at 400-450℃ and holding for 2-3 hours.

6. The fatigue-resistant aluminum alloy wire as described in claim 1, characterized in that: The solution treatment is performed at a heating temperature of 450~500℃, and after holding at that temperature for 2~3 hours, it is quenched to form a supersaturated solid solution.

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