High-creep-resistance aluminum alloy rod for cable, aluminum alloy stranded wire, cable and preparation method of aluminum alloy rod

Abstract

The invention discloses a high-creep-resistance aluminum alloy rod for a cable, an aluminum alloy stranded wire, the cable and a preparation method of the aluminum alloy rod. The aluminum alloy rod comprises the following alloy components in percentage by mass: 0.25-0.60% of iron, 0.25-0.60% of copper, 0.25-0.60% of nickel, 0.25-0.60% of nickel and the balance of aluminum. The mass percent of silicon is 0.08 to 0.25 percent; the mass percent of magnesium is 0.05 to 0.15 percent; the mass percent of the boron is 0.005 to 0.02 percent; the mass percent of the rare earth is 0.01 to 0.03 percent; the total mass percent sum of the impurity elements of titanium, vanadium, manganese and chromium is not more than 0.02%, the mass percent of other single impurity elements is not more than 0.03%, and the total mass percent sum of other impurity elements is not more than 0.10%; and the balance of aluminum. According to the aluminum alloy rod, the creep property, the safety and the stretchability are improved, and the cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of metal processing, and in particular relates to a preparation method of a high creep resistance aluminum alloy rod for a cable, an aluminum alloy stranded wire, a cable, and an aluminum alloy rod. Background Art

[0002] my country is the country with the largest copper consumption in the world, and it is also a country with an extreme shortage of copper. Every year, 80% of copper products are imported to meet domestic demand. In my country, the wire and cable manufacturing industry is, in a sense, a copper processing industry. It can be said that the production of the five major types of wires and cables in my country cannot be separated from copper raw materials. According to statistics, by the end of 2022, the annual output value of my country's wire and cable industry has exceeded one trillion yuan, making it the world's largest cable producer and a major industry in my country second only to the automotive industry. The amount of copper used in cables has reached more than 4 million tons, accounting for nearly 60% of domestic copper consumption. The rapid depletion of copper resources has led to an increase in copper prices, increased the cost of the wire and cable manufacturing industry, and is extremely unfavorable to the development of my country's wire and cable industry. However, my country's bauxite resources are relatively abundant, and aluminum metal has the characteristics of light weight, easy processing, and good conductivity. As for the conductivity, the conductivity of the same quality of aluminum is greater than that of copper wires, so it is theoretically feasible to use aluminum instead of copper as a conductor. However, during long-term use, aluminum core cables are prone to creep, which increases the contact resistance of the cable's middle and terminal joints, leading to problems such as heat and fire at the cable joints. In the early days, this caused the development of the "aluminum instead of copper" policy to stagnate both at home and abroad.

[0003] In foreign countries, as early as the 1830s, the civil construction fields in the United States and Canada had begun to use pure aluminum conductors in power cables. In the mid-1940s (after World War II), in response to the shortage of copper resources, the United States first formulated a technical policy of "replacing copper with aluminum" and stipulated that all relevant industries must implement it. Cable companies, Underwriters Laboratories and related research institutions in the United States began to develop aluminum alloy conductors to overcome the shortcomings of poor creep resistance of pure aluminum conductors, and to overcome the shortcomings of aluminum conductor joints that are prone to creep loosening or poor contact under heat and pressure, resulting in a sharp increase in contact resistance and the easy generation of arcs and sparks to cause fires. With the continuous deepening of the research and development process and the continuous application of new technologies, aluminum alloy conductor cables with better creep resistance than ordinary aluminum have been unanimously recognized by users in developed countries such as the United States, Australia and Canada, and have been used in major civil and commercial buildings and power grid engineering construction.

[0004] Domestically, although my country has already determined "replacing copper with aluminum" as a national technical policy as early as 1957, the development of aluminum alloy cables in my country is much slower than that in foreign countries because the safety of aluminum core cable joints and the installation and laying of hardware have not been fundamentally solved. Since 2006, wire and cable manufacturers in the United States, Canada, Germany and other countries have introduced aluminum alloy wires and cables into my country, which has led to the rapid development of aluminum alloy cables in my country and quickly received unanimous recognition and praise from the majority of power engineering users. In addition, with the rapid development of the new energy industry, the advantages of aluminum alloy conductor cables, such as light weight and low cost, have become more prominent. In recent years, they have won the favor of new energy customers such as wind power and photovoltaics, which has greatly increased the use of aluminum alloy conductors, making it possible for my country to implement the national policy of replacing copper with aluminum and saving copper with aluminum.

[0005] The vast majority of aluminum alloy materials used in aluminum alloy cables on the market today are 8030 aluminum alloy, which is the No. 2 alloy specified in GB / T30552-2014 "Aluminum Alloy Wire for Cable Conductors". The mass fractions of the elements in the chemical composition are required to be: Si≤0.10%, Fe: 0.30%-0.80%, Cu: 0.15%-0.30%, Mg≤0.05%, Zn≤0.05%, B: 0.001-0.04, the mass fraction of other individual elements is ≤0.03%, the total mass fraction of other individual elements is ≤0.10%, and the remainder is Al. The addition of iron to 8030 aluminum alloy can improve the strength and creep resistance of the alloy, but the Fe content (mass fraction) must be properly controlled; at the same time, in order to improve the strength, plasticity and surface brightness of 8030 alloy aluminum rods, a small amount of Cu is also added. Adding Cu to the aluminum alloy will reduce its electrical conductivity, but a small amount of Cu will form CuAl2 compounds with aluminum and melt into the solid solution. During the heat treatment process, it will precipitate as a metal compound, which will make the conductivity of the aluminum alloy slightly better than that of the solid solution state. The Cu content is preferably 0.18%-0.25%. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for preparing a high creep resistant aluminum alloy rod, an aluminum alloy stranded wire, a cable, and an aluminum alloy rod for cables in view of the above-mentioned deficiencies in the prior art. The aluminum alloy rod has improved creep performance, safety, and tensile properties, and reduced costs.

[0007] The technical solution adopted to solve the technical problem of the present invention is to provide a high creep resistance aluminum alloy rod for cables, the alloy composition of which includes:

[0008] The mass percentage of iron is 0.25-0.60%; the mass percentage of silicon is 0.08-0.25%; the mass percentage of magnesium is 0.05-0.15%; the mass percentage of boron is 0.005-0.02%; the mass percentage of rare earth is 0.01-0.03%; the total mass percentage of impurity elements titanium, vanadium, manganese and chromium does not exceed 0.02%, the mass percentage of other individual impurity elements does not exceed 0.03%, and the total mass percentage of other impurity elements does not exceed 0.10%; the rest is aluminum.

[0009] Preferably, the high creep resistance aluminum alloy rod for the cable comprises:

[0010] The mass percentage of iron is 0.25-0.60%; the mass percentage of silicon is 0.08-0.25%; the mass percentage of magnesium is 0.05-0.15%; the mass percentage of boron is 0.005-0.02%; the mass percentage of rare earth is 0.01-0.03%; the total mass percentage of impurity elements titanium, vanadium, manganese and chromium is 0.0001%-0.02%, the mass percentage of other single impurity elements does not exceed 0.03%, and the total mass percentage of other impurity elements does not exceed 0.10%; the rest is aluminum.

[0011] The present invention also provides a high creep resistance aluminum alloy stranded wire, which is formed by twisting high creep resistance aluminum alloy monofilaments, and the high creep resistance aluminum alloy monofilaments are formed by drawing the above-mentioned high creep resistance aluminum alloy rods.

[0012] The present invention also provides a cable, comprising a cable core, wherein the cable core is formed by twisting the above-mentioned high creep resistance aluminum alloy stranded wires.

[0013] The present invention also provides a method for preparing the above-mentioned high creep resistance aluminum alloy rod for cable, comprising the following steps:

[0014] (1) Preparation of aluminum liquid

[0015] Melting 9463-9803 parts by mass of 99.7mas% remelted aluminum ingots to obtain molten aluminum liquid, wherein the 99.7mas% remelted aluminum ingots refer to the remelted aluminum ingots having an aluminum content of not less than 99.7% by mass;

[0016] (2) Melting aluminum alloy liquid

[0017] Add 125-300 parts by weight of aluminum-iron master alloy to the molten aluminum liquid; add 40-125 parts by weight of aluminum-silicon master alloy; add 17-67 parts by weight of aluminum-boron master alloy; add 10-30 parts by weight of aluminum-rare earth master alloy, keep the mixture at 730-750° C. for 20-40 minutes to obtain aluminum alloy liquid; then stop heating and add magnesium ingot;

[0018] Among them, attention should be paid to the addition of the intermediate alloy. 125-300 parts by mass of AlFe20 aluminum-iron intermediate alloy is added to the smelting furnace together with the aluminum ingot in 2-3 times, 40-125 parts by mass of aluminum-silicon intermediate alloy is added to the smelting furnace together with the aluminum ingot in 2 times, 17-67 parts by mass of AlB3 aluminum-boron intermediate alloy is added to the small furnace of the smelting furnace in 2 times, and the molten alloy liquid is put into the holding furnace. When the aluminum alloy liquid is put into 1 / 2 and 3 / 4, 10-30 parts by mass of AlRe10 aluminum rare earth is added to the holding furnace in 2 times. After all the aluminum alloy liquid enters the holding furnace, the temperature of the holding furnace is raised to 740-760°C, and then the heating is stopped. 5-15 parts by mass of 99.95% magnesium ingots are sent into the holding furnace by a frame magnesium feeder and stirred manually for 2 minutes.

[0019] Because magnesium ingots are different from other metal intermediate alloys, the melting point of magnesium ingots is low, only 649℃. Adding magnesium ingots too early is prone to burnout, resulting in the final alloy element ratio not meeting the requirements. When the aluminum liquid in the holding furnace is full, magnesium ingots are added. Because of the low melting point of magnesium ingots, they can be quickly melted by the aluminum liquid temperature, and the burning of magnesium ingots can also be reduced. When the temperature rises to 740-760℃, the rapid melting of magnesium ingots can be accelerated, and the frame-type magnesium feeder enters the aluminum liquid, which can melt the magnesium ingots within a few minutes.

[0020] The plane on the top of the frame-type magnesium feeder is an airtight steel plate, and the other surfaces are welded by steel bar gaps. The bottom is a steel bar gap door that can be opened and closed freely (with a locking device).

[0021] (3) Purification

[0022] The refining agent is introduced into the aluminum alloy liquid for refining, and then the slag is removed; specifically, 0.3-0.4% of the total amount of the charge is blown into the aluminum alloy liquid in the insulation furnace with high-purity nitrogen (99.99%) for refining. The refining time must reach more than 5 minutes, and then electromagnetic stirring is performed. The stirring requirements are: forward rotation for 5 minutes, reverse rotation for 5 minutes, then manual stirring for 2 minutes, then forward rotation for 5 minutes, and then reverse rotation for 5 minutes, with a total stirring time of 22 minutes. Then the slag is removed. There must be no suspended aluminum slag on the surface of the aluminum liquid after the slag removal, and a total of 5 samples are taken from the four sides and the middle of the insulation furnace for spectral analysis.

[0023] (4) Aluminum alloy casting

[0024] Obtaining an aluminum alloy casting bar by casting;

[0025] (5) Aluminum alloy rod rolling

[0026] The aluminum alloy rod is obtained by rolling.

[0027] Preferably, the iron content in the AlFe20 aluminum-iron master alloy in step (2) is 19mas%-21mas%;

[0028] The silicon content in AlSi20 aluminum silicon master alloy is 19mas%-21mas%;

[0029] The boron content in AlB3 aluminum-boron master alloy is 2.5mas%-3.5mas%;

[0030] The rare earth content in AlRe10 aluminum rare earth master alloy is 9mas%-11mas%.

[0031] Preferably, the following steps are further included between step (3) and step (4):

[0032] (a) Keep warm and let stand

[0033] The aluminum alloy solution temperature is controlled at 740-760°C and allowed to stand for 20-40 minutes;

[0034] (b) Degassing treatment

[0035] The aluminum alloy liquid after being left to stand enters the degassing box through the launder, and the degassing box removes hydrogen from the aluminum alloy liquid and absorbs the oxidized slag, so that the aluminum alloy liquid can be purified;

[0036] (c) Aluminum alloy liquid filtration

[0037] Ceramic filtration is used for aluminum alloy liquid.

[0038] Preferably, in step (4), the aluminum alloy liquid flows into the crystallization wheel and the continuous casting machine is started for horizontal (12 o'clock position) casting, the casting temperature of the aluminum alloy liquid is controlled at 690-710°C, and the temperature of the aluminum alloy strip coming out of the continuous casting machine is controlled at 480-500°C.

[0039] Preferably, in the step (5), the aluminum alloy cast bar enters a continuous rolling mill for rolling, and the rolling mill current is controlled at 45-55A, so that it can be rolled into a φ9.5mm aluminum alloy rod. The temperature of the aluminum alloy rod after rolling is in the range of 250-300°C, and then the wire is wound around the rod to obtain the aluminum alloy rod, thus completing the entire process of aluminum alloy rod melting, casting, rolling production and process control.

[0040] Preferably, the mass percentage composition of the remelted aluminum ingot is: 0.07%≤Fe≤0.14%, 0.04%≤Si≤0.08%, 0.0001%≤Cu≤0.01, 0≤Ti+V+Mn+Cr≤0.02%, the remaining impurities content is ≤0.03%, the rest is aluminum, and the mass percentage of aluminum is not less than 99.70%;

[0041] The mass percentage composition of the AlFe20 aluminum-iron master alloy is as follows: 19%≤Fe≤21%, 0.08%≤Si≤0.20%, 0.001%≤Cu≤0.1%, 0≤Ti+V+Mn+Cr≤0.1%, and the remaining impurities content is ≤0.03%, and the rest is aluminum;

[0042] The mass percentage composition of the AlSi20 aluminum-silicon master alloy is as follows: 0.07%≤Fe≤0.20%, 19%≤Si≤21%, 0.001%≤Cu≤0.1%, 0≤Ti+V+Mn+Cr≤0.10%, and the remaining impurities content is ≤0.03%, and the rest is aluminum;

[0043] The mass percentage composition of the 99.95% magnesium ingot is as follows: 0≤Fe≤0.003%, 0≤Si≤0.005%, 0≤Cu≤0.002%, 0≤Ti+V+Mn+Cr≤0.02%, and the content of other impurities is ≤0.02%, and the rest is magnesium, and the mass percentage of magnesium is not less than 99.95%;

[0044] The mass percentage composition of the AlB3 aluminum-boron master alloy is as follows: 2.5%≤B≤3.5%, 0.14%≤Fe≤0.40%, 0.08%≤Si≤0.20%, 0.001%≤Cu≤0.1%, and the remaining impurities content is ≤0.03%, and the rest is aluminum;

[0045] The aluminum rare earth master alloy is AlRe10, and its mass percentage composition is: 9%≤Re≤11%, 0.09%≤Fe≤0.25%, 0.08%≤Si≤0.2%, 0.0001%≤Cu≤0.01%, and the remaining impurity content is ≤0.03%, and the rest is aluminum.

[0046] Preferably, Re10 in the AlRe10 aluminum rare earth master alloy is the sum of various rare earth elements, including lanthanide elements, wherein the mass percentage of each rare earth element is: 4.9%≤Ce≤5.5%, 3.5%≤La≤4.1%, 0.3%≤Pr≤0.7%, and other mixed rare earth elements are 0.3%~0.7%.

[0047] The present invention provides a high creep resistance aluminum alloy rod with a conductivity of not less than 59.0% IACS (standard 29.73% IACS), a tensile strength of 115MPa-130MPa (standard 105-155MPa), and an elongation of 15%-30% (standard 10%) and a preparation method thereof. The process repeatability of the present invention is good and the qualified rate of finished products is high. The DC resistance of the conductive wire core manufactured by the present invention reaches the requirements of the ordinary aluminum conductive wire core of the same specification after aging treatment, and the creep resistance of the aluminum alloy conductive wire core is more than 4 times that of the ordinary aluminum conductive wire core of the same specification, which greatly improves the quality of the aluminum core cable joint.

[0048] The high creep resistance aluminum alloy rod for cable involved in the technology of the present invention breaks the aluminum-iron-copper composition of 8030 and adopts an aluminum-iron-silicon alloy. A large number of tests and test data show that the electromechanical properties of the aluminum alloy conductor of this alloy system are not reduced compared with the 8030 aluminum alloy conductor, but the creep performance is improved by 1 times that of the 8030 aluminum alloy conductor and is 4 times that of ordinary aluminum. It has good safety and further improves the connection performance of aluminum conductors. When the conductor is annealed, the added iron element produces high-strength creep resistance, which can ensure stable connection even under long-term overload and overheating. This type of aluminum alloy greatly improves the tensile strength of pure aluminum, so that the aluminum alloy cable can support 4000 meters of its own weight, while the copper cable can only support 2750 meters. This advantage is particularly prominent in the wiring of large-span buildings (such as stadiums). On the other hand, since the precious element copper is eliminated from the alloy system, its material cost is also lower than that of 8030 aluminum alloy conductor. There is no doubt that when this technology is put on the market, it will be favored by power customers for its better creep performance and lower cost. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with specific implementation methods.

[0050] Example 1

[0051] This embodiment provides a high creep resistance aluminum alloy rod for cables, the alloy composition of which includes:

[0052] The mass percentage of iron is 0.25-0.60%; the mass percentage of silicon is 0.08-

[0053] 0.25%; the mass percentage of magnesium is 0.05-0.15%; the mass percentage of boron is 0.005-0.02%; the mass percentage of rare earth is 0.01-0.03%; the total mass percentage of impurity elements titanium, vanadium, manganese and chromium does not exceed 0.02%, the mass percentage of other individual impurity elements does not exceed 0.03%, and the total mass percentage of other impurity elements does not exceed 0.10%; the rest is aluminum.

[0054] This embodiment also provides a high creep resistance aluminum alloy stranded wire, which is formed by twisting high creep resistance aluminum alloy monofilaments, and the high creep resistance aluminum alloy monofilaments are drawn from the above-mentioned high creep resistance aluminum alloy rods.

[0055] This embodiment also provides a cable, including a cable core, wherein the cable core is formed by twisting the above-mentioned high creep resistance aluminum alloy stranded wires.

[0056] This embodiment also provides a method for preparing the above-mentioned high creep resistance aluminum alloy rod for cables, comprising the following steps:

[0057] (1) Preparation of aluminum liquid

[0058] Melting 9463-9803 parts by mass of 99.7mas% remelted aluminum ingots to obtain molten aluminum liquid, wherein the 99.7mas% remelted aluminum ingots refer to the remelted aluminum ingots having an aluminum content of not less than 99.7% by mass;

[0059] (2) Melting aluminum alloy liquid

[0060] Add 125-300 parts by mass of aluminum-iron master alloy to the molten aluminum liquid; add 40-125 parts by mass of aluminum-silicon master alloy; add 17-67 parts by mass of aluminum-boron master alloy; add 10-30 parts by mass of aluminum-rare earth master alloy, keep it at 730-750°C for 20-40 minutes to obtain aluminum alloy liquid; then stop heating and add magnesium ingot;

[0061] (3) Purification

[0062] The refining agent is introduced into the aluminum alloy liquid for refining, and then the slag is removed;

[0063] (4) Aluminum alloy casting

[0064] Obtaining an aluminum alloy casting bar by casting;

[0065] (5) Aluminum alloy rod rolling

[0066] The aluminum alloy rod is obtained by rolling.

[0067] This embodiment provides a high creep-resistant aluminum alloy rod with a conductivity of not less than 59.0% IACS (standard 29.73% IACS), a tensile strength of 115MPa-130MPa (standard 105-155MPa), and an elongation of 15%-30% (standard 10%) and a preparation method thereof. The process repeatability of this embodiment is good and the qualified rate of finished products is high. The DC resistance of the conductive wire core manufactured by the conductive wire core reaches the requirements of the ordinary aluminum conductive wire core of the same specification after aging treatment. The creep resistance of the aluminum alloy conductive wire core is more than 4 times that of the ordinary aluminum conductive wire core of the same specification, which greatly improves the quality of the aluminum core cable joint.

[0068] The high creep-resistant aluminum alloy rod for cables involved in the technology of this embodiment breaks the aluminum-iron-copper composition of 8030 and adopts an aluminum-iron-silicon alloy. A large number of tests and test data show that the electromechanical properties of the aluminum alloy conductor of this alloy system are not reduced compared with those of the 8030 aluminum alloy conductor, but the creep performance is improved by 1 times that of the 8030 aluminum alloy conductor and is 4 times that of ordinary aluminum. It has good safety and further improves the connection performance of the aluminum conductor. When the conductor is annealed, the added iron element produces high-strength creep resistance, which can ensure stable connection even under long-term overload and overheating. This type of aluminum alloy greatly improves the tensile strength of pure aluminum, so that the aluminum alloy cable can support 4000 meters of its own weight, while the copper cable can only support 2750 meters. This advantage is particularly prominent in the wiring of large-span buildings (such as stadiums). On the other hand, since the precious element copper is eliminated from the alloy system, its material cost is also lower than that of 8030 aluminum alloy conductor. There is no doubt that when this technology is put on the market, it will be favored by power customers for its better creep performance and lower cost.

[0069] Example 2

[0070] This embodiment provides a high creep resistance aluminum alloy rod for cables, the alloy composition of which includes:

[0071] The mass percentage of iron is 0.25-0.60%; the mass percentage of silicon is 0.08-0.25%; the mass percentage of magnesium is 0.05-0.15%; the mass percentage of boron is 0.005-0.02%; the mass percentage of rare earth is 0.01-0.03%; the total mass percentage of impurity elements titanium, vanadium, manganese and chromium does not exceed 0.02%, the mass percentage of other individual impurity elements does not exceed 0.03%, and the total mass percentage of other impurity elements does not exceed 0.10%; the rest is aluminum.

[0072] Preferably, the alloy composition of the high creep resistance aluminum alloy rod for cable includes:

[0073] The mass percentage of iron is 0.25-0.60%; the mass percentage of silicon is 0.08-0.25%; the mass percentage of magnesium is 0.05-0.15%; the mass percentage of boron is 0.005-0.02%; the mass percentage of rare earth is 0.01-0.03%; the total mass percentage of impurity elements titanium, vanadium, manganese and chromium is 0.0001%-0.02%, the mass percentage of other single impurity elements does not exceed 0.03%, and the total mass percentage of other impurity elements does not exceed 0.10%; the rest is aluminum.

[0074] This embodiment also provides a high creep resistance aluminum alloy stranded wire, which is formed by twisting high creep resistance aluminum alloy monofilaments, and the high creep resistance aluminum alloy monofilaments are drawn from the above-mentioned high creep resistance aluminum alloy rods.

[0075] This embodiment also provides a cable, including a cable core, wherein the cable core is formed by twisting the above-mentioned high creep resistance aluminum alloy stranded wires.

[0076] The preparation of a high creep-resistant aluminum alloy rod for cables with a conductivity of not less than 59.0% IACS, a tensile strength of 115-130 MPa, an elongation of not less than 15%, and a creep performance of more than 4 times that of ordinary aluminum is described as follows:

[0077] 1. Material selection

[0078] The preparation method of the high creep-resistant aluminum alloy rod for cable in this embodiment involves the main raw materials including: remelted aluminum ingots containing 99.7mas% Al, magnesium ingots containing 99.95mas% Mg, aluminum-iron master alloy (AlFe20), aluminum-boron master alloy (AlB3), aluminum rare earth master alloy (AlRe10), and aluminum-silicon master alloy (AlSi20).

[0079] The mass percentage composition of the remelted aluminum ingot is: 0.07%≤Fe≤0.14%, 0.04%≤Si≤0.08%, 0.0001%≤Cu≤0.01, 0≤Ti+V+Mn+Cr≤0.02%, the remaining impurities content is ≤0.03%, the rest is aluminum, and the mass percentage of aluminum is not less than 99.7%;

[0080] The mass percentage composition of AlFe20 aluminum-iron master alloy is as follows: 19%≤Fe≤21%, 0.08%≤Si≤0.20%, 0.001%≤Cu≤0.1%, 0≤Ti+V+Mn+Cr≤0.1%, and the remaining impurities are ≤0.03%, and the rest is aluminum;

[0081] The mass percentage composition of AlSi20 aluminum silicon master alloy is as follows: 0.07%≤Fe≤0.20%, 19%≤Si≤21%, 0.001%≤Cu≤0.1%, 0≤Ti+V+Mn+Cr≤0.10%, and the remaining impurities are ≤0.03%, and the rest is aluminum;

[0082] The mass percentage composition of the magnesium ingot is: 0≤Fe≤0.003%, 0≤Si≤0.005%, 0≤Cu≤0.002%, 0≤Ti+V+Mn+Cr≤0.02%, the content of other impurities is ≤0.02%, the rest is magnesium, and the mass percentage of magnesium is not less than 99.95%;

[0083] The mass percentage composition of AlB3 aluminum-boron master alloy is as follows: 2.5%≤B≤3.5%, 0.14%≤Fe≤0.40%, 0.08%≤Si≤0.20%, 0.001%≤Cu≤0.1%, and the remaining impurities are ≤0.03%, and the rest is aluminum;

[0084] The aluminum rare earth master alloy is AlRe10, and its mass percentage composition is: 9%≤Re≤11%, 0.09%≤Fe≤0.25%, 0.08%≤Si≤0.2%, 0.0001%≤Cu≤0.01%, and the content of other impurities is ≤0.03%, and the rest is aluminum.

[0085] Re10 in AlRe10 aluminum rare earth master alloy is the sum of various rare earth elements, including lanthanide elements, wherein the mass percentage of each rare earth element is: 4.9%≤Ce≤5.5%, 3.5%≤La≤4.1%, 0.3%≤Pr≤0.7%, and other mixed rare earth elements are 0.3%~0.7%.

[0086] 2. Alloy formula of aluminum alloy rod

[0087] The alloy composition of the aluminum alloy rod includes:

[0088] The mass percentage of iron is 0.25-0.60%; the mass percentage of silicon is 0.08-0.25%; the mass percentage of magnesium is 0.05-0.15%; the mass percentage of boron is 0.005-0.02%; the mass percentage of rare earth is 0.01-0.03%; the total mass percentage of impurity elements titanium, vanadium, manganese and chromium does not exceed 0.02%, the mass percentage of other individual impurity elements does not exceed 0.03%, and the total mass percentage of other impurity elements does not exceed 0.10%; the rest is aluminum.

[0089] 3. Melting, casting and rolling process control

[0090] Because the remelted aluminum ingot containing 99.7mas% Al contains trace elements such as iron, silicon, copper, magnesium, etc. that affect the accuracy of the furnace formula, as well as other trace elements, the following melting, casting and rolling process is calculated and explained based on the average content of Fe element 0.10mas%, Si element 0.04mas%, Cu element 0.0001mas% (negligible), and Mg element 0.0035mas% (negligible) measured by the 6-month supply of aluminum ingots from Xinjiang Qiya Aluminum and Electricity Co., Ltd.; the magnesium ingot containing 99.95mas% Mg is calculated and explained based on pure magnesium; the aluminum-iron master alloy AlFe20 is calculated and explained based on 20mas% iron, the aluminum-silicon master alloy AlSi20 is calculated and explained based on 20mas% silicon, the aluminum-boron master alloy AlB3 is calculated and explained based on 3mas% boron, and the aluminum-rare earth master alloy AlRe10 is calculated and explained based on 10mas% rare earth. For the convenience of explanation and to ensure the accuracy of the data, the melting, casting and rolling process control is explained based on 10,000 parts by mass per furnace.

[0091] Specifically, this embodiment is described below using a 10-ton aluminum alloy rod as an example.

[0092] This embodiment also provides a method for preparing the above-mentioned high creep resistance aluminum alloy rod for cables, comprising the following steps:

[0093] (1) Preparation of aluminum liquid

[0094] 9803 parts by mass (9803 kg) of 99.7Al remelted aluminum ingots are selected, and then 9803 parts by mass of 99.7mas% remelted aluminum ingots are put into a melting furnace in batches for melting to obtain molten aluminum liquid, wherein the 99.7mas% remelted aluminum ingot refers to a remelted aluminum ingot having an aluminum mass percentage content of not less than 99.7%.

[0095] (2) Melting aluminum alloy liquid

[0096] 125 parts by mass of aluminum-iron master alloy AlFe20 is added to the molten aluminum liquid, wherein the content of iron in the aluminum-iron master alloy is 19mas%-21mas%; 40 parts by mass of aluminum-silicon master alloy is added, wherein the content of silicon in the aluminum-silicon master alloy is 19mas%-21mas%; 17 parts by mass of aluminum-boron master alloy is added, wherein the content of boron in the aluminum-boron master alloy is 2.5mas%-3.5mas%; 10 parts by mass of aluminum-rare earth master alloy is added, wherein the content of rare earth in the aluminum-rare earth master alloy is 9mas%-11mas%; the mixture is kept at 730° C. and allowed to stand for 20 minutes to obtain aluminum alloy liquid (note that regarding the amount of the master alloy, if the 99.7mas% remelted aluminum ingot already contains elements that affect the accuracy of the formula, such as Fe, Si and Mg, the amount of the self-contained elements in the aluminum liquid should be eliminated from the formula. This situation is mainly determined based on the results of the spectral analysis of the raw materials. For the convenience of explanation, these elements are ignored here);

[0097] Among them, attention should be paid when adding the intermediate alloy. 125 parts by mass of AlFe20 aluminum-iron intermediate alloy is added to the smelting furnace together with the aluminum ingot in two times, 40 parts by mass of aluminum-silicon intermediate alloy is added to the smelting furnace together with the aluminum ingot in two times, and 17 parts by mass of AlB3 aluminum-boron intermediate alloy is added to the small furnace of the smelting furnace in two times. The molten alloy liquid is put into the holding furnace. When the aluminum alloy liquid is put into 1 / 2 and 3 / 4, 10 parts by mass of AlRe10 aluminum rare earth is added to the holding furnace in two times. After all the aluminum alloy liquid enters the holding furnace, the temperature of the holding furnace is raised to 740°C, and then the heating is stopped. 5 parts by mass of 99.95mas% magnesium ingots are sent into the holding furnace with a frame magnesium feeder, and manually stirred for 2 minutes to make the 99.95mas% magnesium ingot melt into the aluminum alloy liquid.

[0098] Because magnesium ingots are different from other metal intermediate alloys, the melting point of magnesium ingots is low, only 649℃. Adding magnesium ingots too early is prone to burnout, resulting in the final alloy element ratio not meeting the requirements. When the aluminum liquid in the holding furnace is full, magnesium ingots are added. Due to the low melting point of magnesium ingots, they can be quickly melted by the aluminum liquid temperature, and the burnout of magnesium ingots can also be reduced. When the temperature rises to 740℃, the rapid melting of magnesium ingots can be accelerated, and the frame-type magnesium feeder enters the aluminum liquid, which can melt the magnesium ingots within a few minutes.

[0099] The top plane of the frame-type magnesium feeder is an airtight steel plate, and the other surfaces are welded by steel bar gaps. The bottom is a steel bar gap door that can be opened and closed freely (with a locking device).

[0100] (3) Purification

[0101] Use high-purity nitrogen (99.99%) to blow 0.3% of the total amount of the refining agent into the aluminum alloy liquid in the holding furnace for refining. The refining time must reach more than 5 minutes, and then perform electromagnetic stirring. The stirring requirements are: forward rotation for 5 minutes, reverse rotation for 5 minutes, then manual stirring for 2 minutes, then forward rotation for 5 minutes, and then reverse rotation for 5 minutes, with a total stirring time of 22 minutes. Then slag is removed. There must be no suspended aluminum slag on the surface of the aluminum liquid after slag removal. Take a sample from the four sides and the middle of the holding furnace for a total of 5 samples for spectral analysis. If some individual components do not meet the requirements, they can be added here.

[0102] (4) If additional alloy components are required, the stirring method of step (3) needs to be repeated.

[0103] (5) Keep warm and let stand

[0104] The temperature of the aluminum alloy solution in the holding furnace is controlled at 740°C and allowed to stand for 20 minutes. The aluminum alloy solution must not be stirred during the standing period.

[0105] (6) Degassing treatment

[0106] After standing, the aluminum alloy liquid enters the degassing box through the flow trough. The degassing box removes hydrogen from the aluminum alloy liquid and absorbs oxidized slag to purify the aluminum alloy liquid.

[0107] (7) Aluminum alloy liquid filtration

[0108] The launder is cleaned before casting. The aluminum alloy liquid obtained in step (6) enters the filtering device and is subjected to ceramic filtration outside the furnace. The aluminum alloy liquid passes through the ceramic filter plate to filter out slag nuclei larger than 30 μm. The ceramic filter plate is replaced every two furnaces (about 30 to 35 tons of aluminum liquid).

[0109] (8) Aluminum alloy casting

[0110] The aluminum alloy liquid in step (7) enters the continuous casting stage after passing through the upper and lower pouring pots. The aluminum alloy liquid flows into the crystallization wheel and starts the continuous casting machine for horizontal (12 o'clock position) casting. The casting temperature of the aluminum alloy liquid is controlled at 710°C, and the temperature of the aluminum alloy casting strip coming out of the continuous casting machine is controlled at 490°C.

[0111] (9) Aluminum alloy rod rolling

[0112] The aluminum alloy cast bar produced in step (8) enters a continuous rolling mill for rolling. The rolling mill current is controlled at 45-55A to be rolled into a φ9.5mm aluminum alloy rod. The temperature of the aluminum alloy rod after rolling by the continuous rolling mill is within the range of 280°C. The rod winding device is then wound to obtain an aluminum alloy rod, thus completing the entire process of aluminum alloy rod melting, casting, rolling production and process control.

[0113] This embodiment provides a high creep resistance aluminum alloy rod for cables, the alloy composition of which includes: 0.25% by mass of iron, 0.08% by mass of silicon, 0.05% by mass of magnesium, 0.01% by mass of rare earth, 0.005% by mass of boron, and the remainder is aluminum and unavoidable impurities. The total mass percentage of impurity elements titanium, vanadium, manganese, and chromium is 0.0001% to 0.02%, the mass percentage of other single impurity elements does not exceed 0.03%, and the total mass percentage of other impurity elements does not exceed 0.10%; the rest is aluminum.

[0114] Preferably, the mass percentage composition of the remelted aluminum ingot is: 0.07%≤Fe≤0.14%, 0.04%≤Si≤0.08%, 0.0001%≤Cu≤0.01, 0≤Ti+V+Mn+Cr≤0.02%, the remaining impurities content is ≤0.03%, the rest is aluminum, and the mass percentage of aluminum is not less than 99.7%;

[0115] The mass percentage composition of AlFe20 aluminum-iron master alloy is as follows: 19%≤Fe≤21%, 0.08%≤Si≤0.20%, 0.001%≤Cu≤0.1%, 0≤Ti+V+Mn+Cr≤0.1%, and the remaining impurities are ≤0.03%, and the rest is aluminum;

[0116] The mass percentage composition of AlSi20 aluminum silicon master alloy is as follows: 0.07%≤Fe≤0.20%, 19%≤Si≤21%, 0.001%≤Cu≤0.1%, 0≤Ti+V+Mn+Cr≤0.10%, and the remaining impurities are ≤0.03%, and the rest is aluminum;

[0117] The mass percentage composition of the magnesium ingot is: 0≤Fe≤0.003%, 0≤Si≤0.005%, 0≤Cu≤0.002%, 0≤Ti+V+Mn+Cr≤0.02%, the content of other impurities is ≤0.02%, the rest is magnesium, and the mass percentage of magnesium is not less than 99.95%;

[0118] The mass percentage composition of the aluminum-boron master alloy is as follows: 2.5%≤B≤3.5%, 0.14%≤Fe≤0.40%, 0.08%≤Si≤0.20%, 0.001%≤Cu≤0.1%, and the remaining impurities content is ≤0.03%, and the remaining is aluminum;

[0119] The aluminum rare earth master alloy is AlRe10, and its mass percentage composition is: 9%≤Re≤11%, 0.09%≤Fe≤0.25%, 0.08%≤Si≤0.2%, 0.0001%≤Cu≤0.01%, and the content of other impurities is ≤0.03%, and the rest is aluminum.

[0120] Preferably, Re10 in the AlRe10 aluminum rare earth master alloy is the sum of various rare earth elements, including lanthanide elements, wherein the mass percentage of each rare earth element is: 4.9%≤Ce≤5.5%, 3.5%≤La≤4.1%, 0.3%≤Pr≤0.7%, and other mixed rare earth elements are 0.3%~0.7%.

[0121] This embodiment provides a high creep-resistant aluminum alloy rod with a conductivity of not less than 59.0% IACS (standard 29.73% IACS), a tensile strength of 115MPa-130MPa (standard 105-155MPa), and an elongation of 15%-30% (standard 10%) and a preparation method thereof. The process repeatability of this embodiment is good and the qualified rate of finished products is high. The DC resistance of the conductive wire core manufactured by the conductive wire core reaches the requirements of the ordinary aluminum conductive wire core of the same specification after aging treatment. The creep resistance of the aluminum alloy conductive wire core is more than 4 times that of the ordinary aluminum conductive wire core of the same specification, which greatly improves the quality of the aluminum core cable joint.

[0122] The mechanical properties and electrical properties of the aluminum alloy rod in this embodiment are compared with those of the 8030 aluminum alloy rod in GB / T-3954-2014 electrical round aluminum rod, as shown in Table 1.

[0123] Table 1 Comparison of mechanical and electrical properties of aluminum alloy rods

[0124]

[0125] Table 1

[0126] It can be clearly seen from Table 1 that the aluminum alloy rod in this embodiment is superior to the 8030 aluminum alloy rod in the electrical round aluminum rod of GB / T-3954-2014 in terms of both mechanical properties and electrical properties, which undoubtedly provides a convenient door for the reprocessing of the aluminum alloy rod.

[0127] The high creep-resistant aluminum alloy rod in this embodiment has a conductive core with good comprehensive performance indicators for the finished cable, which will undoubtedly be more favored by users in terms of cable installation, safety, power loss and service life. As can be seen from Table 1, this embodiment controls the tensile strength within a smaller range, the elongation is 50% higher than the national standard, the resistivity is 1.72% lower than the national standard requirement (that is, the conductivity is increased by 1.72%), and its manufacturing cost per ton is nearly 100 yuan lower than that of 8030 aluminum alloy.

[0128] This embodiment is a method for preparing a high creep resistant aluminum alloy rod for cables in order to address the poor creep resistance of ordinary aluminum and further improve the creep resistance of 8030 aluminum alloy materials. The aluminum alloy cable conductor core manufactured using the high creep resistant aluminum alloy rod has a creep resistance that is four times that of ordinary aluminum, and its comprehensive performance is better than that of 8030 aluminum alloy conductors, and all performance indicators are not lower than those specified in GB / T 30552-2014 "Aluminum Alloy Wire for Cable Conductors".

[0129] The aluminum alloy cable produced by using the aluminum alloy rod made in this embodiment has the following advantages:

[0130] 1. Conductive properties

[0131] The electrical conductivity of the aluminum alloy of the aluminum alloy rod in this embodiment is not less than 61.0% of copper IACS (the same as ordinary aluminum), and the current carrying capacity is 79% of copper. 2 When aluminum is used instead of copper within the specification, the aluminum alloy specification should be selected with a larger nominal cross-section; 70-400mm 2 When aluminum is used instead of copper within a specification, the aluminum alloy specification shall select the second largest nominal cross-section.

[0132] 2. Physical and mechanical properties

[0133] The aluminum alloy of the aluminum alloy rod in this embodiment is 30% more flexible than copper and 40% less resilient than copper. The bending radius of the aluminum alloy cable can reach 7 times the outer diameter of the product (copper cable is generally 10 to 15 times), making it easier to connect terminals.

[0134] 3. Creep resistance

[0135] Compared with ordinary aluminum conductors, the aluminum alloy conductor of the aluminum alloy rod in this embodiment has added alloy components such as iron and silicon, and adopts a special processing technology, so that its creep resistance is 400% higher than that of ordinary aluminum (the creep resistance of 8030 aluminum alloy is 300% higher than that of ordinary aluminum), which is close to the creep resistance of copper conductors, eliminating the creep tendency of cable conductors and ensuring that the cable can be stably connected during operation.

[0136] Table 2 is a comparison of creep strain data of four samples of the high creep resistant aluminum alloy, 8030H14 aluminum alloy, T2 (R) type electrical copper wire billet and A4-1A60 electrical round aluminum rod of the aluminum alloy rod in this embodiment. It can be seen that the creep performance of 8030 aluminum alloy is more than 3 times that of ordinary aluminum, and the creep performance of the high creep resistant aluminum alloy of the aluminum alloy rod in this embodiment is 4.28 times that of ordinary aluminum. This also shows that the high creep resistant aluminum alloy of the aluminum alloy rod in this embodiment has the best creep resistance.

[0137] Table 2 Comparison of creep strain of various materials

[0138]

[0139] Table 2

[0140] Note: The data in the table are samples sent by Xinjiang Cable Factory of TBEA Co., Ltd. and tested by Shanghai Cable Research Institute. The test conditions are: test temperature 90℃, compressive stress 76MPa, and time 100h.

[0141] 4. Thermal expansion coefficient

[0142] The thermal expansion coefficient is used to calculate the dimensional change of a material when the temperature changes. The thermal expansion coefficient of the aluminum alloy of the aluminum alloy rod in this embodiment is comparable to that of copper. Aluminum connectors have been reliably used for copper and aluminum conductors for many years, and most electrical connectors used today are made of aluminum. The expansion and contraction of aluminum alloy conductors and connectors are exactly the same. It is more suitable for aluminum alloys.

[0143] 5. Self-weight bearing performance

[0144] The aluminum alloy of the aluminum alloy rod in this embodiment improves the tensile strength of pure aluminum. The aluminum alloy cable can support 4000 meters of deadweight, while the copper cable can only support 2750 meters. This advantage is particularly prominent when wiring in large-span buildings (such as stadiums).

[0145] 6. Anti-corrosion performance

[0146] The inherent corrosion resistance of the aluminum of the aluminum alloy rod in this embodiment is due to the formation of a thin and strong oxide layer when the aluminum surface contacts the air, which is particularly resistant to various forms of corrosion. Even in sulfur-containing environments, such as railway tunnels and other similar places, the corrosion resistance of aluminum alloys is much better than that of copper.

[0147] 7. Environmental performance

[0148] The aluminum alloy cable made of aluminum alloy rods in this embodiment and adopting a bare interlocking armor structure can meet the cold-resistant, halogen-free and low-smoke flame-retardant properties, meet the flame-retardant Class A requirements, and meet the development requirements of an energy-saving, clean and environmentally friendly society.

[0149] 8. Economic performance

[0150] When transmitting the same current carrying capacity, the aluminum alloy cable made of the aluminum alloy rod in this embodiment has a cost about 30% lower than that of the copper cable, and is about 50% lighter, and can be installed without a bridge frame, reducing installation costs by about 30%.

[0151] Aluminum alloy conductors have been used in North America for nearly 50 years and have been unanimously recognized by users in developed countries such as the United States, Australia and Canada. 90% of civil and commercial buildings in North America use aluminum alloy cables. Since the promotion and application of aluminum alloy core cables in my country in 2006, they have also been unanimously recognized and praised by the majority of power engineering application companies. At present, aluminum alloy cables are mainly used in airports, military bases, steel and petrochemicals, commercial entertainment, highway office buildings, residences, hotels, supermarkets, colleges and universities, stadiums, hospitals, factory buildings and other construction projects. As the advantages of aluminum alloy cables are gradually accepted by more application companies, aluminum alloy cables will make great contributions to my country's energy conservation, emission reduction and environmental improvement.

[0152] The high creep-resistant aluminum alloy rod for cables involved in the technology of this embodiment breaks the aluminum-iron-copper composition of 8030 and adopts an aluminum-iron-silicon alloy. A large number of tests and test data show that the electromechanical properties of the aluminum alloy conductor of this alloy system are not reduced compared with those of the 8030 aluminum alloy conductor, but the creep performance is improved by 1 times that of the 8030 aluminum alloy conductor and is 4 times that of ordinary aluminum. It has good safety and further improves the connection performance of the aluminum conductor. When the conductor is annealed, the added iron element produces high-strength creep resistance, which can ensure stable connection even under long-term overload and overheating. This type of aluminum alloy greatly improves the tensile strength of pure aluminum, so that the aluminum alloy cable can support 4000 meters of its own weight, while the copper cable can only support 2750 meters. This advantage is particularly prominent in the wiring of large-span buildings (such as stadiums). On the other hand, since the precious element copper is eliminated from the alloy system, its material cost is also lower than that of 8030 aluminum alloy conductor. There is no doubt that when this technology is put on the market, it will be favored by power customers for its better creep performance and lower cost.

[0153] Example 3

[0154] Specifically, this embodiment is described below using a 10-ton aluminum alloy rod as an example.

[0155] This embodiment also provides a method for preparing the above-mentioned high creep resistance aluminum alloy rod for cables, comprising the following steps:

[0156] (1) Preparation of aluminum liquid

[0157] 9628 parts by mass (9628 kg) of 99.7Al remelted aluminum ingots are selected, and then 9628 parts by mass of 99.7mas% remelted aluminum ingots are put into a melting furnace in batches for melting to obtain molten aluminum liquid, wherein the 99.7mas% remelted aluminum ingot refers to a remelted aluminum ingot having an aluminum mass percentage content of not less than 99.7%.

[0158] (2) Melting aluminum alloy liquid

[0159] Add 215 parts by mass of aluminum-iron master alloy AlFe20 to the molten aluminum liquid, wherein the content of iron in the aluminum-iron master alloy is 19mas%-21mas%; add 85 parts by mass of aluminum-silicon master alloy, wherein the content of silicon in the aluminum-silicon master alloy is 19mas%-21mas%; add 42 parts by mass of aluminum-boron master alloy, wherein the content of boron in the aluminum-boron master alloy is 2.5mas%-3.5mas%; add 20 parts by mass of aluminum-rare earth master alloy, wherein the content of rare earth in the aluminum-rare earth master alloy is 9mas%-11mas%; keep the mixture at 740°C for 30 minutes to obtain aluminum alloy liquid (note that regarding the amount of the master alloy, if the 99.7mas% remelted aluminum ingot already contains elements that affect the accuracy of the formula, such as Fe, Si and Mg, the amount of the self-contained elements in the aluminum liquid should be eliminated in the formula. This situation is mainly determined based on the results of the spectral analysis of the raw materials. For the convenience of explanation, these elements are ignored here);

[0160] Among them, attention should be paid when adding the intermediate alloy. 215 parts by mass of AlFe20 aluminum-iron intermediate alloy is added to the smelting furnace together with the aluminum ingot in two times, 85 parts by mass of aluminum-silicon intermediate alloy is added to the smelting furnace together with the aluminum ingot in two times, and 42 parts by mass of AlB3 aluminum-boron intermediate alloy is added to the small furnace of the smelting furnace in two times. The molten alloy liquid is put into the holding furnace. When the aluminum alloy liquid is put into 1 / 2 and 3 / 4, 20 parts by mass of AlRe10 aluminum rare earth are added to the holding furnace in two times. After all the aluminum alloy liquid enters the holding furnace, the temperature of the holding furnace is raised to 750°C, and then the heating is stopped. 10 parts by mass of 99.95mas% magnesium ingots are fed into the holding furnace with a frame magnesium feeder, and manually stirred for 2 minutes to make the 99.95mas% magnesium ingot melt into the aluminum alloy liquid.

[0161] Because magnesium ingots are different from other metal intermediate alloys, the melting point of magnesium ingots is low, only 649℃. Adding magnesium ingots too early is prone to burnout, resulting in the final alloy element ratio not meeting the requirements. When the aluminum liquid in the holding furnace is full, magnesium ingots are added. Due to the low melting point of magnesium ingots, they can be quickly melted by the aluminum liquid temperature, and the burnout of magnesium ingots can also be reduced. When the temperature rises to 750℃, the rapid melting of magnesium ingots can be accelerated, and the frame-type magnesium feeder enters the aluminum liquid, which can melt the magnesium ingots within a few minutes.

[0162] The top plane of the frame-type magnesium feeder is an airtight steel plate, and the other surfaces are welded by steel bar gaps. The bottom is a steel bar gap door that can be opened and closed freely (with a locking device).

[0163] (3) Purification

[0164] Use high-purity nitrogen (99.99%) to blow 0.4% of the total amount of the refining agent into the aluminum alloy liquid in the holding furnace for refining. The refining time must reach more than 5 minutes, and then perform electromagnetic stirring. The stirring requirements are: forward rotation for 5 minutes, reverse rotation for 5 minutes, then manual stirring for 2 minutes, then forward rotation for 5 minutes, and then reverse rotation for 5 minutes, with a total stirring time of 22 minutes. Then slag is removed. There must be no suspended aluminum slag on the surface of the aluminum liquid after slag removal. Take a sample from the four sides and the middle of the holding furnace for a total of 5 samples for spectral analysis. If some individual components do not meet the requirements, they can be added here.

[0165] (4) If additional alloy components are required, the stirring method of step (3) needs to be repeated.

[0166] (5) Keep warm and let stand

[0167] Control the temperature of the aluminum alloy solution in the holding furnace at 740-760°C and let it stand for 30 minutes. The aluminum alloy solution must not be stirred during the standing period.

[0168] (6) Degassing treatment

[0169] After standing, the aluminum alloy liquid enters the degassing box through the flow trough. The degassing box removes hydrogen from the aluminum alloy liquid and absorbs oxidized slag to purify the aluminum alloy liquid.

[0170] (7) Aluminum alloy liquid filtration

[0171] The launder is cleaned before casting. The aluminum alloy liquid obtained in step (6) enters the filtering device and is subjected to ceramic filtration outside the furnace. The aluminum alloy liquid passes through the ceramic filter plate to filter out slag nuclei larger than 30 μm. The ceramic filter plate is replaced every two furnaces (about 30 to 35 tons of aluminum liquid).

[0172] (8) Aluminum alloy casting

[0173] The aluminum alloy liquid in step (7) enters the continuous casting stage after passing through the upper and lower pouring pots. The aluminum alloy liquid flows into the crystallization wheel and starts the continuous casting machine for horizontal (12 o'clock position) casting. The casting temperature of the aluminum alloy liquid is controlled at 690-710°C, and the temperature of the aluminum alloy casting strip coming out of the continuous casting machine is controlled at 480-500°C.

[0174] (9) Aluminum alloy rod rolling

[0175] The aluminum alloy cast bar produced in step (8) enters a continuous rolling mill for rolling. The rolling mill current is controlled at 45-55A, and the aluminum alloy rod with a diameter of 9.5 mm can be rolled. The temperature of the aluminum alloy rod after rolling by the continuous rolling mill is in the range of 250-300°C. The rod winding device is then wound to obtain an aluminum alloy rod, thus completing the entire process of aluminum alloy rod melting, casting, rolling production and process control.

[0176] The mass percentage composition of the remelted aluminum ingot is: 0.07%≤Fe≤0.14%, 0.04%≤Si≤0.08%, 0.0001%≤Cu≤0.01, 0≤Ti+V+Mn+Cr≤0.02%, the remaining impurities content is ≤0.03%, the rest is aluminum, and the mass percentage of aluminum is not less than 99.7%;

[0177] The mass percentage composition of the aluminum-iron master alloy is: 19%≤Fe≤21%, 0.08%≤Si≤0.20%, 0.001%≤Cu≤0.1%, 0≤Ti+V+Mn+Cr≤0.1%, and the remaining impurities content is ≤0.03%, and the rest is aluminum;

[0178] The mass percentage composition of the aluminum-silicon master alloy is as follows: 0.07%≤Fe≤0.20%, 19%≤Si≤21%, 0.001%≤Cu≤0.1%, 0≤Ti+V+Mn+Cr≤0.10%, and the content of other impurities is ≤0.03%, and the rest is aluminum;

[0179] The mass percentage composition of the magnesium ingot is: 0≤Fe≤0.003%, 0≤Si≤0.005%, 0≤Cu≤0.002%, 0≤Ti+V+Mn+Cr≤0.02%, the content of other impurities is ≤0.02%, the rest is magnesium, and the mass percentage of magnesium is not less than 99.95%;

[0180] The mass percentage composition of the aluminum-boron master alloy is as follows: 2.5%≤B≤3.5%, 0.14%≤Fe≤0.40%, 0.08%≤Si≤0.20%, 0.001%≤Cu≤0.1%, and the remaining impurities content is ≤0.03%, and the remaining is aluminum;

[0181] The aluminum rare earth master alloy is AlRe10, and its mass percentage composition is: 9%≤Re≤11%, 0.09%≤Fe≤0.25%, 0.08%≤Si≤0.2%, 0.0001%≤Cu≤0.01%, and the content of other impurities is ≤0.03%, and the rest is aluminum.

[0182] Re10 in the aluminum rare earth master alloy is the sum of various rare earth elements, including lanthanide elements, wherein the mass percentage of each rare earth element is: 4.9%≤Ce≤5.5%, 3.5%≤La≤4.1%, 0.3%≤Pr≤0.7%, and other mixed rare earth elements are 0.3% to 0.7%.

[0183] This embodiment provides a high creep-resistant aluminum alloy rod for cables obtained by the above-mentioned preparation method, and its alloy composition includes: 0.43% by mass of iron, 0.17% by mass of silicon, 0.10% by mass of magnesium, 0.02% by mass of rare earth, 0.03% by mass of boron, and the remainder is aluminum and unavoidable impurities. The total mass percentage of impurity elements titanium, vanadium, manganese, and chromium does not exceed 0.02%, the mass percentage of other single impurity elements does not exceed 0.03%, and the total mass percentage of other impurity elements does not exceed 0.10%; the rest is aluminum.

[0184] This embodiment also provides a high creep resistance aluminum alloy stranded wire, which is formed by twisting high creep resistance aluminum alloy monofilaments, and the high creep resistance aluminum alloy monofilaments are drawn from the above-mentioned high creep resistance aluminum alloy rods.

[0185] This embodiment also provides a cable, including a cable core, wherein the cable core is formed by twisting the above-mentioned high creep resistance aluminum alloy stranded wires.

[0186] This embodiment provides a high creep-resistant aluminum alloy rod with a conductivity of not less than 59.0% IACS (standard 29.73% IACS), a tensile strength of 115MPa-130MPa (standard 105-155MPa), and an elongation of 15%-30% (standard 10%) and a preparation method thereof. The process repeatability of this embodiment is good and the qualified rate of finished products is high. The DC resistance of the conductive wire core manufactured by the conductive wire core reaches the requirements of the ordinary aluminum conductive wire core of the same specification after aging treatment. The creep resistance of the aluminum alloy conductive wire core is more than 4 times that of the ordinary aluminum conductive wire core of the same specification, which greatly improves the quality of the aluminum core cable joint.

[0187] The mechanical properties and electrical properties of the aluminum alloy rod in this embodiment are compared with those of the 8030 aluminum alloy rod in GB / T-3954-2014 electrical round aluminum rod, as shown in Table 3.

[0188] Table 3 Comparison of mechanical and electrical properties of aluminum alloy rods

[0189]

[0190] Table 3

[0191] It can be clearly seen from Table 3 that the aluminum alloy rod in this embodiment is superior to the 8030 aluminum alloy rod in the electrical round aluminum rod of GB / T-3954-2014 in terms of both mechanical and electrical properties. The aluminum alloy cable produced using the aluminum alloy rod made in this embodiment has the following advantages:

[0192] 1. Conductive properties

[0193] The electrical conductivity of the aluminum alloy of the aluminum alloy rod in this embodiment is not less than 61.0% of copper IACS (the same as ordinary aluminum), and the current carrying capacity is 79% of copper. 2 When aluminum is used instead of copper within the specification, the aluminum alloy specification should be selected with a larger nominal cross-section; 70-400mm 2 When aluminum is used instead of copper within a specification, the aluminum alloy specification shall select the second largest nominal cross-section.

[0194] 2. Physical and mechanical properties

[0195] The aluminum alloy of the aluminum alloy rod in this embodiment is 30% more flexible than copper and 40% less resilient than copper. The bending radius of the aluminum alloy cable can reach 7 times the outer diameter of the product (copper cable is generally 10 to 15 times), making it easier to connect terminals.

[0196] 3. Creep resistance

[0197] Compared with ordinary aluminum conductors, the aluminum alloy conductor of the aluminum alloy rod in this embodiment has added alloy components such as iron and silicon, and adopts a special processing technology, so that its creep resistance is 400% higher than that of ordinary aluminum (the creep resistance of 8030 aluminum alloy is 300% higher than that of ordinary aluminum), which is close to the creep resistance of copper conductors, eliminating the creep tendency of cable conductors and ensuring that the cable can be stably connected during operation.

[0198] Table 4 is a comparison of creep strain data of four samples of the high creep resistant aluminum alloy, 8030H14 aluminum alloy, T2 (R) type electrical copper wire billet and A4-1A60 electrical round aluminum rod of the aluminum alloy rod in this embodiment. It can be seen that the creep performance of 8030 aluminum alloy is more than 3 times that of ordinary aluminum, and the creep performance of the high creep resistant aluminum alloy of the aluminum alloy rod in this embodiment is 4.45 times that of ordinary aluminum. This also shows that the high creep resistant aluminum alloy of the aluminum alloy rod in this embodiment has the best creep resistance.

[0199] Table 4 Comparison of creep strain of various materials

[0200]

[0201] Table 4

[0202] Note: The data in the table are samples sent by Xinjiang Cable Factory of TBEA Co., Ltd. and tested by Shanghai Cable Research Institute. The test conditions are: test temperature 90℃, compressive stress 76MPa, and time 100h. 4. Thermal expansion coefficient

[0203] The thermal expansion coefficient is used to calculate the dimensional change of a material when the temperature changes. The thermal expansion coefficient of the aluminum alloy of the aluminum alloy rod in this embodiment is comparable to that of copper. Aluminum connectors have been reliably used for copper and aluminum conductors for many years, and most electrical connectors used today are made of aluminum. The expansion and contraction of aluminum alloy conductors and connectors are exactly the same. It is more suitable for aluminum alloys.

[0204] 5. Self-weight bearing performance

[0205] The aluminum alloy of the aluminum alloy rod in this embodiment improves the tensile strength of pure aluminum. The aluminum alloy cable can support 4000 meters of deadweight, while the copper cable can only support 2750 meters. This advantage is particularly prominent when wiring in large-span buildings (such as stadiums).

[0206] 6. Anti-corrosion performance

[0207] The inherent corrosion resistance of the aluminum of the aluminum alloy rod in this embodiment is due to the formation of a thin and strong oxide layer when the aluminum surface contacts the air, which is particularly resistant to various forms of corrosion. Even in sulfur-containing environments, such as railway tunnels and other similar places, the corrosion resistance of aluminum alloys is much better than that of copper.

[0208] 7. Environmental performance

[0209] The aluminum alloy cable made of aluminum alloy rods in this embodiment and adopting a bare interlocking armor structure can meet the cold-resistant, halogen-free and low-smoke flame-retardant properties, meet the flame-retardant Class A requirements, and meet the development requirements of an energy-saving, clean and environmentally friendly society.

[0210] 8. Economic performance

[0211] When transmitting the same current carrying capacity, the aluminum alloy cable made of the aluminum alloy rod in this embodiment has a cost about 30% lower than that of the copper cable, and is about 50% lighter, and can be installed without a bridge frame, reducing installation costs by about 30%.

[0212] Aluminum alloy conductors have been used in North America for nearly 50 years and have been unanimously recognized by users in developed countries such as the United States, Australia and Canada. 90% of civil and commercial buildings in North America use aluminum alloy cables. Since the promotion and application of aluminum alloy core cables in my country in 2006, they have also been unanimously recognized and praised by the majority of power engineering application companies. At present, aluminum alloy cables are mainly used in airports, military bases, steel and petrochemicals, commercial entertainment, highway office buildings, residences, hotels, supermarkets, colleges and universities, stadiums, hospitals, factory buildings and other construction projects. As the advantages of aluminum alloy cables are gradually accepted by more application companies, aluminum alloy cables will make great contributions to my country's energy conservation, emission reduction and environmental improvement.

[0213] The high creep-resistant aluminum alloy rod for cables involved in the technology of this embodiment breaks the aluminum-iron-copper composition of 8030 and adopts an aluminum-iron-silicon alloy. A large number of tests and test data show that the electromechanical properties of the aluminum alloy conductor of this alloy system are not reduced compared with those of the 8030 aluminum alloy conductor, but the creep performance is improved by 1 times that of the 8030 aluminum alloy conductor and is 4 times that of ordinary aluminum. It has good safety and further improves the connection performance of the aluminum conductor. When the conductor is annealed, the added iron element produces high-strength creep resistance, which can ensure stable connection even under long-term overload and overheating. This type of aluminum alloy greatly improves the tensile strength of pure aluminum, so that the aluminum alloy cable can support 4000 meters of its own weight, while the copper cable can only support 2750 meters. This advantage is particularly prominent in the wiring of large-span buildings (such as stadiums). On the other hand, since the precious element copper is eliminated from the alloy system, its material cost is also lower than that of 8030 aluminum alloy conductor. There is no doubt that when this technology is put on the market, it will be favored by power customers for its better creep performance and lower cost.

[0214] Example 4

[0215] Specifically, this embodiment is described below using a 10-ton aluminum alloy rod as an example.

[0216] This embodiment also provides a method for preparing the above-mentioned high creep resistance aluminum alloy rod for cables, comprising the following steps:

[0217] (1) Preparation of aluminum liquid

[0218] 9463 parts by mass (9463 kg) of 99.7Al remelted aluminum ingots are selected, and then 9463 parts by mass of 99.7mas% remelted aluminum ingots are put into a melting furnace in batches for melting to obtain molten aluminum liquid, wherein the 99.7mas% remelted aluminum ingot refers to a remelted aluminum ingot having an aluminum mass percentage content of not less than 99.7%.

[0219] (2) Melting aluminum alloy liquid

[0220] 300 parts by mass of aluminum-iron master alloy AlFe20 is added to the molten aluminum liquid, wherein the content of iron in the aluminum-iron master alloy is 19mas%-21mas%; 125 parts by mass of aluminum-silicon master alloy is added, wherein the content of silicon in the aluminum-silicon master alloy is 19mas%-21mas%; 67 parts by mass of aluminum-boron master alloy is added, wherein the content of boron in the aluminum-boron master alloy is 2.5mas%-3.5mas%; 30 parts by mass of aluminum-rare earth master alloy is added, wherein the content of rare earth in the aluminum-rare earth master alloy is 9mas%-11mas%; the mixture is kept at 750° C. and allowed to stand for 40 minutes to obtain aluminum alloy liquid (note that regarding the amount of the master alloy, if the 99.7mas% remelted aluminum ingot already contains elements that affect the accuracy of the formula, such as Fe, Si and Mg, the amount of the self-contained elements in the aluminum liquid should be eliminated in the formula. This situation is mainly determined based on the results of the spectral analysis of the raw materials. For the convenience of explanation, these elements are ignored here);

[0221] Among them, attention should be paid when adding the intermediate alloy. 300 parts by mass of AlFe20 aluminum-iron intermediate alloy are added to the smelting furnace together with the aluminum ingot in two times, 125 parts by mass of aluminum-silicon intermediate alloy are added to the smelting furnace together with the aluminum ingot in two times, and 67 parts by mass of AlB3 aluminum-boron intermediate alloy are added to the small furnace of the smelting furnace in two times. The molten alloy liquid is put into the holding furnace. When the aluminum alloy liquid is put into 1 / 2 and 3 / 4, 30 parts by mass of AlRe10 aluminum rare earth are added to the holding furnace in two times. After all the aluminum alloy liquid enters the holding furnace, the temperature of the holding furnace is raised to 760°C, and then the heating is stopped. 15 parts by mass of 99.95mas% magnesium ingots are fed into the holding furnace with a frame magnesium feeder, and manually stirred for 2 minutes to make the 99.95mas% magnesium ingot melt into the aluminum alloy liquid.

[0222] Because magnesium ingots are different from other metal intermediate alloys, the melting point of magnesium ingots is low, only 649℃. Adding magnesium ingots too early is prone to burnout, resulting in the final alloy element ratio not meeting the requirements. When the aluminum liquid in the holding furnace is full, magnesium ingots are added. Due to the low melting point of magnesium ingots, they can be quickly melted by the aluminum liquid temperature, and the burnout of magnesium ingots can also be reduced. When the temperature rises to 760℃, the rapid melting of magnesium ingots can be accelerated, and the frame-type magnesium feeder enters the aluminum liquid, which can melt the magnesium ingots within a few minutes.

[0223] The top plane of the frame-type magnesium feeder is an airtight steel plate, and the other surfaces are welded by steel bar gaps. The bottom is a steel bar gap door that can be opened and closed freely (with a locking device).

[0224] (3) Purification

[0225] Use high-purity nitrogen (99.99%) to blow 0.35% of the total amount of the charge into the aluminum alloy liquid in the holding furnace for refining. The refining time must be more than 5 minutes, and then electromagnetic stirring is performed. The stirring requirements are: forward rotation for 5 minutes, reverse rotation for 5 minutes, then manual stirring for 2 minutes, then forward rotation for 5 minutes, and reverse rotation for 5 minutes, with a total stirring time of 22 minutes. Then slag is removed. There must be no suspended aluminum slag on the surface of the aluminum liquid after slag removal. Take a sample from the four sides and the middle of the holding furnace for a total of 5 samples for spectral analysis. If some individual components do not meet the requirements, they can be added here.

[0226] (4) If additional alloy components are required, the stirring method of step (3) needs to be repeated.

[0227] (5) Keep warm and let stand

[0228] The temperature of the aluminum alloy solution in the holding furnace is controlled at 760°C and allowed to stand for 40 minutes. The aluminum alloy solution must not be stirred during the standing period.

[0229] (6) Degassing treatment

[0230] After standing, the aluminum alloy liquid enters the degassing box through the flow trough. The degassing box removes hydrogen from the aluminum alloy liquid and absorbs oxidized slag to purify the aluminum alloy liquid.

[0231] (7) Aluminum alloy liquid filtration

[0232] The launder is cleaned before casting. The aluminum alloy liquid obtained in step (6) enters the filtering device and is subjected to ceramic filtration outside the furnace. The aluminum alloy liquid passes through the ceramic filter plate to filter out slag nuclei larger than 30 μm. The ceramic filter plate is replaced every two furnaces (about 30 to 35 tons of aluminum liquid).

[0233] (8) Aluminum alloy casting

[0234] The aluminum alloy liquid in step (7) enters the continuous casting stage after passing through the upper and lower pouring pots. The aluminum alloy liquid flows into the crystallization wheel and starts the continuous casting machine for horizontal (12 o'clock position) casting. The casting temperature of the aluminum alloy liquid is controlled at 690°C, and the temperature of the aluminum alloy casting strip coming out of the continuous casting machine is controlled at 500°C.

[0235] (9) Aluminum alloy rod rolling

[0236] The aluminum alloy cast bar produced in step (8) enters a continuous rolling mill for rolling. The rolling mill current is controlled at 45-55A, and the aluminum alloy rod with a diameter of 9.5 mm can be rolled. The temperature of the aluminum alloy rod after rolling by the continuous rolling mill is within the range of 300°C. The rod winding device then winds up the wire to obtain an aluminum alloy rod, thus completing the entire process of aluminum alloy rod melting, casting, rolling production and process control.

[0237] This embodiment provides a high creep-resistant aluminum alloy rod for cables obtained by the above-mentioned preparation method, and its alloy composition includes: 0.60% by mass of iron, 0.25% by mass of silicon, 0.15% by mass of magnesium, 0.03% by mass of rare earth, 0.02% by mass of boron, and the remainder is aluminum and unavoidable impurities. The total mass percentage of impurity elements titanium, vanadium, manganese, and chromium is 0.0001% to 0.02%, the mass percentage of other single impurity elements does not exceed 0.03%, and the total mass percentage of other impurity elements does not exceed 0.10%; the rest is aluminum.

[0238] This embodiment also provides a high creep resistance aluminum alloy stranded wire, which is formed by twisting high creep resistance aluminum alloy monofilaments, and the high creep resistance aluminum alloy monofilaments are drawn from the above-mentioned high creep resistance aluminum alloy rods.

[0239] This embodiment also provides a cable, including a cable core, wherein the cable core is formed by twisting the above-mentioned high creep resistance aluminum alloy stranded wires.

[0240] The mass percentage composition of the remelted aluminum ingot is: 0.07%≤Fe≤0.14%, 0.04%≤Si≤0.08%, 0.0001%≤Cu≤0.01, 0≤Ti+V+Mn+Cr≤0.02%, the remaining impurities content is ≤0.03%, the rest is aluminum, and the mass percentage of aluminum is not less than 99.7%;

[0241] The mass percentage composition of the aluminum-iron master alloy is: 19%≤Fe≤21%, 0.08%≤Si≤0.20%, 0.001%≤Cu≤0.1%, 0≤Ti+V+Mn+Cr≤0.1%, and the remaining impurities content is ≤0.03%, and the rest is aluminum;

[0242] The mass percentage composition of the aluminum-silicon master alloy is as follows: 0.07%≤Fe≤0.20%, 19%≤Si≤21%, 0.001%≤Cu≤0.1%, 0≤Ti+V+Mn+Cr≤0.10%, and the content of other impurities is ≤0.03%, and the rest is aluminum;

[0243] The mass percentage composition of the magnesium ingot is: 0≤Fe≤0.003%, 0≤Si≤0.005%, 0≤Cu≤0.002%, 0≤Ti+V+Mn+Cr≤0.02%, the content of other impurities is ≤0.02%, the rest is magnesium, and the mass percentage of magnesium is not less than 99.95%;

[0244] The mass percentage composition of the aluminum-boron master alloy is as follows: 2.5%≤B≤3.5%, 0.14%≤Fe≤0.40%, 0.08%≤Si≤0.20%, 0.001%≤Cu≤0.1%, and the remaining impurities content is ≤0.03%, and the remaining is aluminum;

[0245] The aluminum rare earth master alloy is AlRe10, and its mass percentage composition is: 9%≤Re≤11%, 0.09%≤Fe≤0.25%, 0.08%≤Si≤0.2%, 0.0001%≤Cu≤0.01%, and the content of other impurities is ≤0.03%, and the rest is aluminum.

[0246] Re10 in the aluminum rare earth master alloy is the sum of various rare earth elements, including lanthanide elements, wherein the mass percentage of each rare earth element is: 4.9%≤Ce≤5.5%, 3.5%≤La≤4.1%, 0.3%≤Pr≤0.7%, and other mixed rare earth elements are 0.3% to 0.7%.

[0247] This embodiment provides a high creep-resistant aluminum alloy rod with a conductivity of not less than 59.0% IACS (standard 29.73% IACS), a tensile strength of 115MPa-130MPa (standard 105-155MPa), and an elongation of 15%-30% (standard 10%) and a preparation method thereof. The process repeatability of this embodiment is good and the qualified rate of finished products is high. The DC resistance of the conductive wire core manufactured by the conductive wire core reaches the requirements of the ordinary aluminum conductive wire core of the same specification after aging treatment. The creep resistance of the aluminum alloy conductive wire core is more than 4 times that of the ordinary aluminum conductive wire core of the same specification, which greatly improves the quality of the aluminum core cable joint.

[0248] The mechanical properties and electrical properties of the aluminum alloy rod in this embodiment are compared with those of the 8030 aluminum alloy rod in GB / T-3954-2014 electrical round aluminum rod, as shown in Table 5.

[0249] Table 5 Comparison of mechanical and electrical properties of aluminum alloy rods

[0250]

[0251]

[0252] Table 5

[0253] It can be clearly seen from Table 5 that the aluminum alloy rod in this embodiment is superior to the 8030 aluminum alloy rod in the electrical round aluminum rod of GB / T-3954-2014 in terms of both mechanical properties and electrical properties.

[0254] The aluminum alloy cable produced by using the aluminum alloy rod made in this embodiment has the following advantages:

[0255] 1. Conductive properties

[0256] The electrical conductivity of the aluminum alloy of the aluminum alloy rod in this embodiment is not less than 61.0% of copper IACS (the same as ordinary aluminum), and the current carrying capacity is 79% of copper. 2 When aluminum is used instead of copper within the specification, the aluminum alloy specification should be selected with a larger nominal cross-section; 70-400mm2 When aluminum is used instead of copper within a specification, the aluminum alloy specification shall select the second largest nominal cross-section.

[0257] 2. Physical and mechanical properties

[0258] The aluminum alloy of the aluminum alloy rod in this embodiment is 30% more flexible than copper and 40% less resilient than copper. The bending radius of the aluminum alloy cable can reach 7 times the outer diameter of the product (copper cable is generally 10 to 15 times), making it easier to connect terminals.

[0259] 3. Creep resistance

[0260] Compared with ordinary aluminum conductors, the aluminum alloy conductor of the aluminum alloy rod in this embodiment has added alloy components such as iron and silicon, and adopts a special processing technology, so that its creep resistance is 400% higher than that of ordinary aluminum (the creep resistance of 8030 aluminum alloy is 300% higher than that of ordinary aluminum), which is close to the creep resistance of copper conductors, eliminating the creep tendency of cable conductors and ensuring that the cable can be stably connected during operation.

[0261] Table 6 is a comparison of creep strain data of four samples of the high creep resistant aluminum alloy, 8030H14 aluminum alloy, T2 (R) type electrical copper wire billet and A4-1A60 electrical round aluminum rod of the aluminum alloy rod in this embodiment. It can be seen that the creep performance of 8030 aluminum alloy is more than 3 times that of ordinary aluminum, and the creep performance of the high creep resistant aluminum alloy of the aluminum alloy rod in this embodiment is 4.63 times that of ordinary aluminum. This also shows that the high creep resistant aluminum alloy of the aluminum alloy rod in this embodiment has the best creep resistance.

[0262] Table 6 Comparison of creep strain of various materials

[0263]

[0264] Table 6

[0265] Note: The data in the table are samples sent by Xinjiang Cable Factory of TBEA Co., Ltd. and tested by Shanghai Cable Research Institute. The test conditions are: test temperature 90℃, compressive stress 76MPa, and time 100h.

[0266] 4. Thermal expansion coefficient

[0267] The thermal expansion coefficient is used to calculate the dimensional change of a material when the temperature changes. The thermal expansion coefficient of the aluminum alloy of the aluminum alloy rod in this embodiment is comparable to that of copper. Aluminum connectors have been reliably used for copper and aluminum conductors for many years, and most electrical connectors used today are made of aluminum. The expansion and contraction of aluminum alloy conductors and connectors are exactly the same. It is more suitable for aluminum alloys.

[0268] 5. Self-weight bearing performance

[0269] The aluminum alloy of the aluminum alloy rod in this embodiment improves the tensile strength of pure aluminum. The aluminum alloy cable can support 4000 meters of deadweight, while the copper cable can only support 2750 meters. This advantage is particularly prominent when wiring in large-span buildings (such as stadiums).

[0270] 6. Anti-corrosion performance

[0271] The inherent corrosion resistance of the aluminum of the aluminum alloy rod in this embodiment is due to the formation of a thin and strong oxide layer when the aluminum surface contacts the air, which is particularly resistant to various forms of corrosion. Even in sulfur-containing environments, such as railway tunnels and other similar places, the corrosion resistance of aluminum alloys is much better than that of copper.

[0272] 7. Environmental performance

[0273] The aluminum alloy cable made of aluminum alloy rods in this embodiment and adopting a bare interlocking armor structure can meet the cold-resistant, halogen-free and low-smoke flame-retardant properties, meet the flame-retardant Class A requirements, and meet the development requirements of an energy-saving, clean and environmentally friendly society.

[0274] 8. Economic performance

[0275] When transmitting the same current carrying capacity, the aluminum alloy cable made of the aluminum alloy rod in this embodiment has a cost about 30% lower than that of the copper cable, and is about 50% lighter, and can be installed without a bridge frame, reducing installation costs by about 30%.

[0276] Aluminum alloy conductors have been used in North America for nearly 50 years and have been unanimously recognized by users in developed countries such as the United States, Australia and Canada. 90% of civil and commercial buildings in North America use aluminum alloy cables. Since the promotion and application of aluminum alloy core cables in my country in 2006, they have also been unanimously recognized and praised by the majority of power engineering application companies. At present, aluminum alloy cables are mainly used in airports, military bases, steel and petrochemicals, commercial entertainment, highway office buildings, residences, hotels, supermarkets, colleges and universities, stadiums, hospitals, factory buildings and other construction projects. As the advantages of aluminum alloy cables are gradually accepted by more application companies, aluminum alloy cables will make great contributions to my country's energy conservation, emission reduction and environmental improvement.

[0277] The high creep-resistant aluminum alloy rod for cables involved in the technology of this embodiment breaks the aluminum-iron-copper composition of 8030 and adopts an aluminum-iron-silicon alloy. A large number of tests and test data show that the electromechanical properties of the aluminum alloy conductor of this alloy system are not reduced compared with those of the 8030 aluminum alloy conductor, but the creep performance is improved by 1 times that of the 8030 aluminum alloy conductor and is 4 times that of ordinary aluminum. It has good safety and further improves the connection performance of the aluminum conductor. When the conductor is annealed, the added iron element produces high-strength creep resistance, which can ensure stable connection even under long-term overload and overheating. This type of aluminum alloy greatly improves the tensile strength of pure aluminum, so that the aluminum alloy cable can support 4000 meters of its own weight, while the copper cable can only support 2750 meters. This advantage is particularly prominent in the wiring of large-span buildings (such as stadiums). On the other hand, since the precious element copper is eliminated from the alloy system, its material cost is also lower than that of 8030 aluminum alloy conductor. There is no doubt that when this technology is put on the market, it will be favored by power customers for its better creep performance and lower cost.

[0278] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A high creep resistance aluminum alloy rod for cable, characterized in that: Its alloy composition includes: The mass percentage of iron is 0.25-0.60%; the mass percentage of silicon is 0.08-0.25%; the mass percentage of magnesium is 0.05-0.15%; the mass percentage of boron is 0.005-0.02%; the mass percentage of rare earth is 0.01-0.03%; the total mass percentage of impurity elements titanium, vanadium, manganese and chromium does not exceed 0.02%, the mass percentage of other individual impurity elements does not exceed 0.03%, and the total mass percentage of other impurity elements does not exceed 0.10%; the rest is aluminum.

2. The high creep resistance aluminum alloy rod for cable according to claim 1, characterized in that: The high creep resistance aluminum alloy rod alloy composition for this cable includes: The mass percentage of iron is 0.25-0.60%; the mass percentage of silicon is 0.08-0.25%; the mass percentage of magnesium is 0.05-0.15%; the mass percentage of boron is 0.005-0.02%; the mass percentage of rare earth is 0.01-0.03%; the total mass percentage of impurity elements titanium, vanadium, manganese and chromium is 0.0001%-0.02%, the mass percentage of other single impurity elements does not exceed 0.03%, and the total mass percentage of other impurity elements does not exceed 0.10%; the rest is aluminum.

3. A high creep resistance aluminum alloy stranded wire, characterized in that: The high creep resistant aluminum alloy single wire is twisted and formed, and the high creep resistant aluminum alloy single wire is drawn from the high creep resistant aluminum alloy rod described in claim 1 or 2.

4. A cable, characterized in that: The cable comprises a cable core, which is formed by twisting the high creep resistance aluminum alloy stranded wires as described in claim 3.

5. A method for preparing a high creep resistant aluminum alloy rod for a cable according to claim 1 or 2, characterized in that: The following steps are involved: (1) Preparation of aluminum liquid Melting 9463-9803 parts by mass of 99.7mas% remelted aluminum ingots to obtain molten aluminum liquid, wherein the 99.7mas% remelted aluminum ingots refer to the remelted aluminum ingots having an aluminum content of not less than 99.7% by mass; (2) Melting aluminum alloy liquid Add 125-300 parts by weight of aluminum-iron master alloy to the molten aluminum liquid; add 40-125 parts by weight of aluminum-silicon master alloy; add 17-67 parts by weight of aluminum-boron master alloy; add 10-30 parts by weight of aluminum-rare earth master alloy, keep the mixture at 730-750° C. for 20-40 minutes to obtain aluminum alloy liquid; then stop heating and add magnesium ingot; (3) Purification The refining agent is introduced into the aluminum alloy liquid for refining, and then the slag is removed; (4) Aluminum alloy casting Obtaining an aluminum alloy casting bar by casting; (5) Aluminum alloy rod rolling The aluminum alloy rod is obtained by rolling.

6. The method for preparing a high creep resistant aluminum alloy rod for a cable according to claim 5, characterized in that: The content of iron in the aluminum-iron master alloy in step (2) is 19mas%-21mas%; The silicon content in the aluminum silicon master alloy is 19mas%-21mas%; The boron content in the aluminum-boron master alloy is 2.5mas%-3.5mas%; The rare earth content in the aluminum rare earth master alloy is 9mas%-11mas%.

7. The method for preparing a high creep resistant aluminum alloy rod for a cable according to claim 5, characterized in that: The following steps are also included between step (3) and step (4): (a) Keep warm and let stand The aluminum alloy solution temperature is controlled at 740-760°C and allowed to stand for 20-40 minutes; (b) Degassing treatment The aluminum alloy liquid after being left to stand enters the degassing box through the launder, and the degassing box removes hydrogen from the aluminum alloy liquid and absorbs the oxidized slag, so that the aluminum alloy liquid can be purified; (c) Aluminum alloy liquid filtration Ceramic filtration is used for aluminum alloy liquid.

8. The method for preparing a high creep resistant aluminum alloy rod for a cable according to claim 5, characterized in that: In the step (4), the aluminum alloy liquid flows into the crystallization wheel and the continuous casting machine is started for horizontal casting. The casting temperature of the aluminum alloy liquid is controlled at 690-710°C, and the temperature of the aluminum alloy strips coming out of the continuous casting machine is controlled at 480-500°C.

9. The method for preparing a high creep resistant aluminum alloy rod for a cable according to claim 5, characterized in that: In the step (5), the aluminum alloy cast bar enters a continuous rolling mill for rolling, and the temperature of the aluminum alloy rod after rolling is in the range of 250 to 300° C., and then the rod is wound and wound to obtain an aluminum alloy rod.

10. The method for preparing a high creep resistance aluminum alloy rod for a cable according to any one of claims 5 to 9, characterized in that: The mass percentage composition of the remelted aluminum ingot is: 0.07%≤Fe≤0.14%, 0.04%≤Si≤0.08%, 0.0001%≤Cu≤0.01, 0≤Ti+V+Mn+Cr≤0.02%, the remaining impurities content is ≤0.03%, the rest is aluminum, and the mass percentage of aluminum is not less than 99.7%; The aluminum-iron master alloy has the following mass percentage composition: 19%≤Fe≤21%, 0.08%≤Si≤0.20%, 0.001%≤Cu≤0.1%, 0≤Ti+V+Mn+Cr≤0.1%, and the remaining impurities content is ≤0.03%, and the rest is aluminum; The mass percentage composition of the aluminum-silicon master alloy is as follows: 0.07%≤Fe≤0.20%, 19%≤Si≤21%, 0.001%≤Cu≤0.1%, 0≤Ti+V+Mn+Cr≤0.10%, and the content of other impurities is ≤0.03%, and the rest is aluminum; The mass percentage composition of the magnesium ingot is: 0≤Fe≤0.003%, 0≤Si≤0.005%, 0≤Cu≤0.002%, 0≤Ti+V+Mn+Cr≤0.02%, the remaining impurities content is ≤0.02%, the rest is magnesium, and the mass percentage of magnesium is not less than 99.95%; The mass percentage composition of the aluminum-boron master alloy is as follows: 2.5%≤B≤3.5%, 0.14%≤Fe≤0.40%, 0.08%≤Si≤0.20%, 0.001%≤Cu≤0.1%, and the remaining impurities content is ≤0.03%, and the rest is aluminum; The aluminum rare earth master alloy is AlRe10, and its mass percentage composition is: 9%≤Re≤11%, 0.09%≤Fe≤0.25%, 0.08%≤Si≤0.2%, 0.0001%≤Cu≤0.01%, and the remaining impurity content is ≤0.03%, and the rest is aluminum.

11. The method for preparing a high creep resistant aluminum alloy rod for a cable according to claim 10, characterized in that: Re10 in the aluminum rare earth master alloy is the sum of various rare earth elements, including lanthanide elements, wherein the mass percentage of each rare earth element is: 4.9%≤Ce≤5.5%, 3.5%≤La≤4.1%, 0.3%≤Pr≤0.7%, and other mixed rare earth elements are 0.3% to 0.7%.

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