6-series aluminum conducting bar for aluminum alloy bus duct and preparation method of 6-series aluminum conducting bar

Abstract

The invention relates to the field of aluminum alloy bus ducts, in particular to a 6-series aluminum conducting bar for an aluminum alloy bus duct and a preparation method of the 6-series aluminum conducting bar. The content of Mg is 0.35 to 0.60 percent; fe content is less than or equal to 0.3%; the content of Cu is less than or equal to 0.05%; the content of Mn is less than or equal to 0.05%; the Zn content is less than or equal to 0.1%; the single content of other impurity elements is less than or equal to 0.03%; the total content of other impurity elements is less than or equal to 0.1%; the balance is Al; the content of Mg2Si is 0.80-0.90%, the IACS (International Annealed Copper Standard) of the conducting bar can reach 57% or above, and the tensile strength is greater than or equal to 120MPa.

Description

Technical Field

[0001] The present invention relates to the field of aluminum alloy busbars, and specifically relates to a 6-series aluminum conductive bar for aluminum alloy busbars and a preparation method thereof. Background Art

[0002] A busbar is a new type of conductor formed by using copper or aluminum as a conductor, wrapping it with an insulating material and installing it in a metal shell. It is mainly used for equipment for centralized power supply and distribution in the power system, and is widely used in large buildings such as industrial factories, airports, and shopping malls. An aluminum alloy busbar refers to a busbar in which both the conductor and the shell are made of aluminum alloy. Most of the conductive bars of aluminum alloy busbars use 6-series aluminum alloy. The 6-series aluminum alloy is an aluminum alloy with magnesium and silicon as the main alloying elements, belonging to heat-treatable strengthened aluminum alloy. This series of alloys has high strength and good formability, and is widely used in fields such as rail transit and automobile manufacturing.

[0003] The technical problems existing in the conductive bars for aluminum alloy busbars in the prior art are that after extrusion molding, the aging system of T4 or T6 is mostly adopted, and the conductivity is mostly about 50% IACS, or even lower. Low conductivity will lead to unsmooth power transmission, and mechanical equipment cannot obtain stable power supply, resulting in unstable operation and reduced efficiency of the equipment, and even failures. At the same time, a large amount of heat will be generated when transmitting large currents, which will cause the conductive bar and the equipment to overheat, trigger a short circuit, and even cause a fire accident. In addition, low conductivity will increase power loss, and long-term use will increase the power cost.

[0004] Therefore, there is an urgent need to provide an aluminum conductive bar with high conductivity and excellent mechanical properties and a preparation method thereof. Summary of the Invention

[0005] The present invention aims to solve the technical problem of how to provide an aluminum conductive bar with high conductivity and excellent mechanical properties and a preparation method thereof, and further solve the problems of insufficient power supply, unstable operation of equipment, high power cost, short circuit, and potential safety hazards caused by low conductivity.

[0006] To achieve the above object, in the first aspect of the present invention, a 6-series aluminum conductive bar for aluminum alloy busbars is provided, wherein the components and their weight percentages in the conductive bar are as follows:

[0007] The content of Si is 0.3 - 0.6%;

[0008] The content of Mg is 0.35 - 0.60%;

[0009] The content of Fe ≤ 0.3%;

[0010] The content of Cu ≤ 0.05%;

[0011] The content of Mn ≤ 0.05%;

[0012] The Zn content ≤ 0.1%;

[0013] The individual content of other impurity elements ≤ 0.03%;

[0014] The total content of other impurity elements ≤ 0.1%;

[0015] The balance is Al;

[0016] Among them, the Mg2Si content is 0.80 - 0.90%.

[0017] The second aspect of the present invention provides a preparation method of a 6 - series aluminum conducting bar for the above - mentioned aluminum alloy busbar. Among them, the method includes:

[0018] Melting, casting, homogenization treatment, turning, extrusion, quenching, heat treatment;

[0019] The conditions of the melting include: no waste materials are added, the melting temperature is 720 - 750 °C. When the raw material is liquid aluminum alloy, a refining agent is added to the liquid aluminum alloy for refining. After refining, slag skimming is carried out, and it is left standing for 15 - 25 min, and then casting is carried out;

[0020] The conditions of the casting include: the diameter of the casting rod is 194 - 200 mm, the length of the casting rod is 600 - 700 mm, the casting temperature is 700 - 720 °C, and the casting speed is 80 - 110 mm / min;

[0021] Among them, at the beginning of casting, an aluminum - titanium - boron wire is added to the liquid aluminum alloy for grain refinement treatment, and degassing treatment is carried out on the solution during casting.

[0022] The beneficial effects of the present invention are:

[0023] By optimizing the alloy composition and controlling the melting and casting and extrusion processes, the prepared aluminum conducting bar has improved conductivity, and the tensile strength ≥ 120 MPa. Further, a specific heat treatment process makes the performance of the aluminum conducting bar more excellent. Brief Description of the Drawings

[0024] Figure 1 It is a cross - sectional view of the aluminum conducting bar;

[0025] Figure 2 It is a schematic diagram of the conductivity test points of the aluminum conducting bar;

[0026] Figure 3 It is a schematic diagram of the tensile strength specimen of the aluminum conducting bar;

[0027] Figure 4 It is the aluminum conducting bar for production use. Detailed Description of the Invention

[0028] The endpoints and any values in the ranges disclosed herein are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0029] In the prior art, with the existing alloy components and preparation processes, it is difficult to prepare a highly conductive aluminum busbar, making it difficult for the conductivity of the aluminum busbar to meet the requirements.

[0030] In the present invention, the inventors found that by controlling the alloy components and adjusting the processing technology, the conductivity of the 6-series aluminum busbar for aluminum alloy busbar can be improved and a certain tensile strength can be ensured.

[0031] To achieve this goal, the inventors tried to optimize the composition and processing technology of each component of the 6-series aluminum busbar for aluminum alloy busbar. The inventors found that through specific compositions of each component and melting and casting processes, the above object can be achieved. Further, specific extrusion processes, quenching, and heat treatment make the performance of the aluminum busbar more excellent.

[0032] In the first aspect of the present invention, there is provided a 6-series aluminum busbar for aluminum alloy busbar, wherein the components and their weight percentages in the busbar are as follows:

[0033] The Si content is 0.3 - 0.6%;

[0034] The Mg content is 0.35 - 0.60%;

[0035] The Fe content ≤ 0.3%;

[0036] The Cu content ≤ 0.05%;

[0037] The Mn content ≤ 0.05%;

[0038] The Zn content ≤ 0.1%;

[0039] The content of each other impurity element ≤ 0.03%;

[0040] The total content of other impurity elements ≤ 0.1%;

[0041] The balance is Al;

[0042] Among them, the Mg2Si content is 0.80 - 0.90%.

[0043] In the present invention, controlling the Mg2Si content within the range of 0.80 - 0.90% prevents the content from being too high, resulting in excessive lattice distortion, increasing the scattering of electrons, and reducing the conductivity.

[0044] Strictly control the Fe content ≤ 0.3%. As an impurity element, when iron element dissolves into the aluminum matrix, it will cause lattice distortion, damage the crystal structure. When electrons move in the lattice, it will increase the scattering probability, reduce the average freedom degree of electrons, increase the resistance, and lower the conductivity. Moreover, iron element and other elements will form intermetallic compounds, which will hinder the conduction of electrons, cause electrons to scatter at the interface, increase the resistance, and the intermetallic compounds will lead to uneven electric field distribution, affect electron transport, and thus reduce the conductivity.

[0045] The second aspect of the present invention provides a preparation method of a 6-series aluminum conductive bar for the above aluminum alloy busbar, wherein the method includes:

[0046] Smelting, casting, homogenization treatment, turning, extrusion, quenching, heat treatment;

[0047] The conditions for the smelting include: no waste materials are added, the smelting temperature is 720 - 750 °C. When the raw material is liquid aluminum alloy, the refining agent is added to the liquid aluminum alloy for refining, and after refining, slag skimming treatment is carried out, and it is left standing for 15 - 25 min, and then casting is carried out;

[0048] The conditions for the casting include: the diameter of the cast bar is 194 - 200 mm, the length of the cast bar is 600 - 700 mm, the casting temperature is 700 - 720 °C, and the casting speed is 80 - 110 mm / min;

[0049] Among them, at the beginning of casting, aluminum-titanium-boron wire is added to the liquid aluminum alloy for grain refinement treatment, and degassing treatment is carried out on the solution during casting.

[0050] In the present invention, during the melting and casting process, strictly control the content of iron element to prevent lattice distortion, the formation of intermetallic compounds, increase the scattering probability, increase the resistance, affect electron transport, and lead to a decrease in conductivity. At the same time, no waste materials are added during the melting and casting process to reduce the impurity content of the cast bar. Through homogenization treatment of the cast bar, the composition segregation in the alloy can be eliminated, the internal crystal structure of the alloy can be improved, and the turning process is added to further eliminate surface impurities and defects, reduce the product quality. In addition, by adjusting process parameters such as smelting temperature, casting temperature, and casting speed, defects such as hot cracks, slag inclusions, hydrogen absorption, pores, and shrinkage cavities can be prevented.

[0051] According to the present invention, the conditions for the homogenization treatment include: 540 - 550 °C × 5 - 7 h.

[0052] According to the present invention, the conditions for the turning include: the turning thickness is 3 - 6 mm.

[0053] According to the present invention, the conditions for the extrusion include: the outer circumferential diameter is 159 - 161 mm, and the cross-sectional area is 945 - 960 mm 2, the diameter of the extrusion cylinder is 205 - 215 mm, and the extrusion coefficient is 30 - 40.

[0054] According to the present invention, the conditions for extrusion include: the heating temperature of the extrusion cylinder is 445 - 455 °C, a flat die is used for the die, the heating temperature of the die is 485 - 515 °C, the heating temperature of the head of the casting rod is 490 - 510 °C, the heating temperature of the tail of the casting rod is 480 - 500 °C, and the extrusion speed is 4 - 5.5 m / min.

[0055] According to the present invention, the conditions for quenching include: the water cooling speed is 3 - 5 m / min, the outlet temperature is 510 - 530 °C. After quenching, online stretching is carried out, the stretching amount is 0.8 - 1.2%, and after stretching, the head and tail are cut off, 0.5 - 0.6 m of the head is removed, and 1.5 - 1.6 m of the tail is removed.

[0056] In the present invention, the outlet temperature is strictly controlled within the range of 510 - 530 °C to prevent the overburning of the strengthening phase Mg2Si due to too high an outlet temperature, resulting in coarse grain structure, reduced electrical conductivity. At the same time, the water cooling speed during quenching should be strictly controlled to prevent the growth of the grain structure, ensure a good solution state, and form the Mg2Si strengthening phase.

[0057] According to the present invention, the conditions for heat treatment include: the heat treatment system is T4 heat treatment + annealing at 295 - 305 °C for 2.5 - 3.5 h + single-stage aging at 255 - 265 °C for 3 - 19 h.

[0058] In the present invention, after the alloy is annealed, the irregular dislocation structures and other defects inside the crystal can be effectively eliminated, thereby improving the electrical conductivity of the conductive bar. After the alloy is aged, the concentration of solutes in the alloy matrix can be reduced, the precipitated phases can be coarsened, and the scattering of electrons caused by lattice distortion can be reduced, thereby improving the electrical conductivity of the conductive bar. Both heat treatment systems can improve the electrical conductivity. Combining the two heat treatment systems can further improve the electrical conductivity on this basis. While improving the electrical conductivity, it is necessary to ensure that it has a certain strength to be applicable in the aluminum alloy busbar. Therefore, the system, time, and temperature of heat treatment are the most crucial.

[0059] In the present invention, the T4 heat treatment is natural aging to a stable state, and the aging time is not less than 96 h.

[0060] In the present invention, the conductive bar can be obtained by sawing the profile after heat treatment according to the size, and whether to carry out processing is determined according to the usage situation.

[0061] Testing method

[0062] For the electrical conductivity detection, the profile after heat treatment is subjected to electrical conductivity detection. Five detection points are evenly selected on a 1 m profile specimen for detection, and the point marks are point 1, point 2, point 3, point 4, and point 5 respectively. The instruction manual is attached Figure 2Schematic diagram of conductivity test points for aluminum conductive bars.

[0063] For the tensile strength test, three tensile test specimens are made from a 1m profile specimen that has completed the conductivity test, and the tensile strength test is carried out. The instruction manual is attached Figure 3 Schematic diagram of the tensile strength test specimen.

[0064] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the embodiments described herein are only partial embodiments of the present invention and are not used to limit the present invention. All other embodiments implemented by those of ordinary skill in the art based on the embodiments of the present invention without making creative improvements belong to the protection scope of the present invention.

[0065] Embodiment 1

[0066] Smelting and casting: The raw materials for the conductive bar are prepared according to the following weight parts: Si: 0.4%, Mg: 0.55%, Fe: 0.2%, Cu: 0.03%, Mn: 0.04%, Zn: 0.08%, the single content of other impurity elements ≤ 0.03%, the total content of other impurity elements ≤ 0.1%, the balance is Al, the content of Mg2Si is 0.85%, no waste is added, and it is placed in a smelting furnace for smelting. The smelting temperature is 730°C. When the raw material is liquid aluminum alloy, a refining agent is added to the liquid aluminum alloy for refining. After refining, slag skimming is carried out, and it is left standing for 20 min, then casting is carried out. The diameter of the cast rod is 198 mm, the length of the cast rod is 680 mm, the casting temperature is 710°C, the casting speed is 95 mm / min. At the beginning of casting, an aluminum-titanium-boron wire is added to the liquid aluminum alloy for grain refinement treatment. At the same time, degassing treatment is carried out on the solution during casting to reduce the hydrogen content in the liquid aluminum alloy.

[0067] Homogenization treatment: After casting, homogenization treatment is carried out on the cast rod, specifically 540°C × 6h.

[0068] Skin turning: The cast rod is processed, and the skin turning thickness is 4 mm, that is, the diameter of the cast rod after skin turning is 190 mm.

[0069] Extrusion: The outer diameter of the profile is 160 mm, and the cross-sectional area is 952.27 mm 2 , a 2000T extrusion press is selected, the diameter of the extrusion cylinder is 210 mm, the heating temperature of the extrusion cylinder is 450°C, the extrusion ratio is 36, a flat die is used for the die, the heating temperature of the die is 510°C, the cast rod is heated by a head-tail gradient temperature, the heating temperature of the head of the cast rod is 500°C, the heating temperature of the tail is 490°C, the outlet temperature is 520°C, the extrusion speed is 4.8 m / min, after extrusion, water cooling quenching is carried out, the water cooling speed is 4.2 m / min, after quenching, online stretching is carried out, the stretching amount is 1.1%, and then head and tail cutting is carried out, 0.5 m is cut off from the head and 1.5 m is cut off from the tail.

[0070] Heat treatment: Cut the profiles into lengths of 1 m, and then the heat treatment system is T4 heat treatment + annealing at 300 °C for 3 h + single-stage aging at 260 °C for 19 h.

[0071] Aluminum conductive bar A1 is obtained.

[0072] Example 2

[0073] Prepare the aluminum conductive bar according to the processing method of Example 1, except that the aluminum alloy components are Si: 0.3%, Mg: 0.35%, Fe: 0.28%, Cu: 0.04%, Mn: 0.03%, Zn: 0.07%, and the Mg2Si content is 0.80%.

[0074] Aluminum conductive bar A2 is obtained.

[0075] Example 3

[0076] Prepare the aluminum conductive bar according to the processing method of Example 1, except that the aluminum alloy components are Si: 0.6%, Mg: 0.60%, Fe: 0.3%, Cu: 0.05%, Mn: 0.05%, Zn: 0.1%, and the Mg2Si content is 0.90%.

[0077] Aluminum conductive bar A3 is obtained.

[0078] Example 4

[0079] Prepare the aluminum conductive bar according to the processing method of Example 1, except that the melting temperature is 720 °C, slag skimming is carried out after refining, standing for 15 min, casting is carried out, the diameter of the casting rod is 196 mm, the length of the casting rod is 600 mm, the casting temperature is 700 °C, and the casting speed is 80 mm / min.

[0080] Aluminum conductive bar A4 is obtained.

[0081] Example 5

[0082] Prepare the aluminum conductive bar according to the processing method of Example 1, except that the melting temperature is 750 °C, slag skimming is carried out after refining, standing for 25 min, casting is carried out, the diameter of the casting rod is 199 mm, the length of the casting rod is 700 mm, the casting temperature is 720 °C, and the casting speed is 110 mm / min.

[0083] Aluminum conductive bar A5 is obtained.

[0084] Example 6

[0085] Prepare the aluminum conductive bar according to the processing method of Example 1, except that the homogenization treatment is 540 °C × 5 h.

[0086] Aluminum conductive bar A6 is obtained.

[0087] Example 7

[0088] Prepare the aluminum busbar according to the processing method of Example 1, except that the homogenization treatment is 550 °C × 7 h.

[0089] Obtain the aluminum busbar A7.

[0090] Example 8

[0091] Prepare the aluminum busbar according to the processing method of Example 1, except that the skin thickness is 3 mm. In the extrusion process, the outside diameter of the circumscribed circle is 159.6 mm, and the cross-sectional area is 949.87 mm 2 , the diameter of the extrusion cylinder is 212 mm, the extrusion coefficient is 39, the heating temperature of the extrusion cylinder is 445 °C, a flat die is used for the die, the heating temperature of the die is 485 °C, the heating temperature of the head of the casting rod is 490 °C, the heating temperature of the tail of the casting rod is 480 °C, and the extrusion speed is 4 m / min.

[0092] Obtain the aluminum busbar A8.

[0093] Example 9

[0094] Prepare the aluminum busbar according to the processing method of Example 1, except that the skin thickness is 5 mm. In the extrusion process, the outside diameter of the circumscribed circle is 160.6 mm, and the cross-sectional area is 955.87 mm 2 , the diameter of the extrusion cylinder is 208 mm, the extrusion coefficient is 35, the heating temperature of the extrusion cylinder is 455 °C, a flat die is used for the die, the heating temperature of the die is 515 °C, the heating temperature of the head of the casting rod is 510 °C, the heating temperature of the tail of the casting rod is 500 °C, and the extrusion speed is 5.5 m / min.

[0095] Obtain the aluminum busbar A9.

[0096] Example 10

[0097] Prepare the aluminum busbar according to the processing method of Example 1, except that in the quenching process, the water cooling speed is 3 m / min, the outlet temperature is 510 °C. After quenching, online stretching is carried out, the stretching amount is 0.8%, and after stretching, the head and tail are cut off, 0.55 m of the head is removed, and 1.6 m of the tail is removed.

[0098] Obtain the aluminum busbar A10.

[0099] Example 11

[0100] Prepare the aluminum busbar according to the processing method of Example 1, except that in the quenching process, the water cooling speed is 5 m / min, the outlet temperature is 530 °C. After quenching, online stretching is carried out, the stretching amount is 1.2%, and after stretching, the head and tail are cut off, 0.6 m of the head is removed, and 1.6 m of the tail is removed.

[0101] The aluminum conductive bar A11 was obtained.

[0102] Example 12

[0103] The aluminum conductive bar was prepared according to the processing method of Example 1. The difference is that in the heat treatment process, the heat treatment system is T4 heat treatment + annealing at 295 °C for 2.5 h + single-stage aging at 255 °C for 3 h.

[0104] The aluminum conductive bar A12 was obtained.

[0105] Example 13

[0106] The aluminum conductive bar was prepared according to the processing method of Example 1. The difference is that in the heat treatment process, the heat treatment system is T4 heat treatment + annealing at 305 °C for 3.5 h + single-stage aging at 265 °C for 19 h.

[0107] The aluminum conductive bar A13 was obtained.

[0108] Comparative Example 1

[0109] The aluminum conductive bar was prepared according to the processing method of Example 1. The difference is that the aluminum alloy components are Si: 0.26%, Mg: 0.3%, Fe: 0.33%, Cu: 0.07%, Mn: 0.06%, Zn: 0.13%, and the Mg2Si content is 0.77%.

[0110] The aluminum conductive bar DA1 was obtained.

[0111] Comparative Example 2

[0112] The aluminum conductive bar was prepared according to the processing method of Example 1. The difference is that the aluminum alloy components are Si: 0.64%, Mg: 0.7%, Fe: 0.36%, Cu: 0.06%, Mn: 0.08%, Zn: 0.15%, and the Mg2Si content is 0.93%.

[0113] The aluminum conductive bar DA2 was obtained.

[0114] Comparative Example 3

[0115] The aluminum conductive bar was prepared according to the processing method of Example 1. The difference is that the melting temperature is 710 °C. After refining, slag skimming is carried out, and it is left standing for 10 min, followed by casting. The diameter of the cast rod is 190 mm, the length of the cast rod is 580 mm, the casting temperature is 680 °C, and the casting speed is 75 mm / min.

[0116] The aluminum conductive bar DA3 was obtained.

[0117] Comparative Example 4

[0118] Prepare an aluminum conductive bar according to the processing method of Example 1, except that the melting temperature is 760°C, slag skimming is carried out after refining, standing for 30 min, followed by casting. The diameter of the cast bar is 202 mm, the length of the cast bar is 730 mm, the casting temperature is 740°C, and the casting speed is 120 mm / min.

[0119] Obtain the aluminum conductive bar DA4.

[0120] Comparative Example 5

[0121] Prepare an aluminum conductive bar according to the processing method of Example 1, except that the homogenization treatment is 520°C × 4 h.

[0122] Obtain the aluminum conductive bar DA5.

[0123] Comparative Example 6

[0124] Prepare an aluminum conductive bar according to the processing method of Example 1, except that the homogenization treatment is 570°C × 8 h.

[0125] Obtain the aluminum conductive bar DA6.

[0126] Comparative Example 7

[0127] Prepare an aluminum conductive bar according to the processing method of Example 1, except that the skin thickness is 2 mm. In the extrusion process, the outer diameter of the circumscribed circle is 158 mm, the cross-sectional area is 940.27 mm 2 , the diameter of the extrusion cylinder is 200 mm, the extrusion ratio is 26, the heating temperature of the extrusion cylinder is 400°C, the die uses a flat die, the heating temperature of the die is 470°C, the heating temperature of the head of the cast bar is 480°C, the heating temperature of the tail of the cast bar is 470°C, and the extrusion speed is 3.6 m / min.

[0128] Obtain the aluminum conductive bar DA7.

[0129] Comparative Example 8

[0130] Prepare an aluminum conductive bar according to the processing method of Example 1, except that the skin thickness is 7 mm. In the extrusion process, the outer diameter of the circumscribed circle is 162.5 mm, the cross-sectional area is 967.27 mm 2 , the diameter of the extrusion cylinder is 220 mm, the extrusion ratio is 44, the heating temperature of the extrusion cylinder is 465°C, the die uses a flat die, the heating temperature of the die is 520°C, the heating temperature of the head of the cast bar is 520°C, the heating temperature of the tail of the cast bar is 510°C, and the extrusion speed is 6.2 m / min.

[0131] Obtain the aluminum conductive bar A8.

[0132] Comparative Example 9

[0133] Prepare an aluminum busbar according to the processing method of Example 1, except that in the quenching process, the water cooling speed is 2.5 m / min, the outlet temperature is 500 °C, followed by on-line stretching after quenching with a stretching amount of 0.5%, and then head and tail trimming after stretching, removing 0.4 m from the head and 1.4 m from the tail.

[0134] Obtain the aluminum busbar DA9.

[0135] Comparative Example 10

[0136] Prepare an aluminum busbar according to the processing method of Example 1, except that in the quenching process, the water cooling speed is 6 m / min, the outlet temperature is 540 °C, followed by on-line stretching after quenching with a stretching amount of 1.5%, and then head and tail trimming after stretching, removing 0.8 m from the head and 1.8 m from the tail.

[0137] Obtain the aluminum busbar DA10.

[0138] Comparative Example 11

[0139] Prepare an aluminum busbar according to the processing method of Example 1, except that in the heat treatment process, the heat treatment regime is T4 heat treatment + annealing at 280 °C for 2 h + single-stage aging at 245 °C for 2 h.

[0140] Obtain the aluminum busbar DA11.

[0141] Comparative Example 12

[0142] Prepare an aluminum busbar according to the processing method of Example 1, except that in the heat treatment process, the heat treatment regime is T4 heat treatment + annealing at 320 °C for 4 h + single-stage aging at 285 °C for 20 h.

[0143] Obtain the aluminum busbar DA12.

[0144] Comparative Example 13

[0145] Prepare an aluminum busbar according to the processing method of Example 1, except that in the heat treatment process, the heat treatment regime is T4 heat treatment.

[0146] Obtain the aluminum busbar DA13.

[0147] Comparative Example 14

[0148] Prepare an aluminum busbar according to the processing method of Example 1, except that in the heat treatment process, the heat treatment regime is T6 heat treatment.

[0149] Obtain the aluminum busbar DA14.

[0150] Comparative Example 15

[0151] Prepare an aluminum current-carrying bar according to the processing method of Example 1, except that in the heat treatment process, the heat treatment regime is single-stage aging at 260°C for 19 h.

[0152] Obtain an aluminum current-carrying bar DA15.

[0153] Comparative Example 16

[0154] Prepare an aluminum current-carrying bar according to the processing method of Example 1, except that in the heat treatment process, the heat treatment regime is annealing at 300°C for 3 h.

[0155] Obtain an aluminum current-carrying bar DA16.

[0156] Perform performance tests on A1 - A13 and DA1 - DA16, as shown in Table 1

[0157] Table 1

[0158]

[0159]

[0160] By comparing the examples and comparative examples, it can be seen that the aluminum current-carrying bar provided by the present invention has excellent electrical conductivity and also maintains excellent tensile strength.

[0161] The aluminum current-carrying bar provided by the present invention improves the electrical conductivity of the aluminum current-carrying bar for aluminum alloy busbar channels to above 57% IACS and has a tensile strength ≥ 120 MPa by strictly controlling the alloy composition, melting and casting, and profile extrusion processes. Further, by regulating the heat treatment process, the electrical conductivity of the current-carrying bar can be made more excellent.

[0162] In the prior art, the electrical conductivity of the 6-series aluminum current-carrying bar for aluminum alloy busbar channels is usually about 50% IACS and it is difficult to reach above 57% IACS. The reason is that the content of impurity elements in the aluminum alloy matrix is relatively high, and the alloy composition, melting and casting, and extrusion and other production processes are not strictly controlled. At the same time, the heat treatment regime is single, and the temperature and time of heat treatment are not well controlled. Even if the electrical conductivity reaches 57% IACS, the tensile strength is too low to meet the use requirements of the aluminum current-carrying bar in the aluminum alloy busbar channel. The aluminum current-carrying bar provided by the technical solution of the present invention has a conductivity above 57% IACS.

[0163] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A 6-series aluminum conductive bar for aluminum alloy bus ducts, characterized in that, The components and their weight percentages in the conductive bar are as follows: The Si content is 0.3 - 0.6%; The Mg content is 0.35 - 0.60%; The Fe content ≤ 0.3%; The Cu content ≤ 0.05%; The Mn content ≤ 0.05%; The Zn content ≤ 0.1%; The single content of other impurity elements ≤ 0.03%; The total content of other impurity elements ≤ 0.1%; The balance is Al; Among them, the Mg2Si content is 0.80 - 0.90%.

2. A preparation method of a 6-series aluminum conductive bar for an aluminum alloy busbar as described in claim 1, characterized in that, The method includes: Smelting, casting, homogenization treatment, turning, extrusion, quenching, heat treatment; The conditions of the smelting include: no scrap is added, the smelting temperature is 720 - 750 °C. When the raw material is liquid aluminum alloy, the refining agent is added to the liquid aluminum alloy for refining. After refining, slag skimming is carried out, and it is left standing for 15 - 25 min before casting; The conditions of the casting include: the diameter of the cast rod is 194 - 200 mm, the length of the cast rod is 600 - 700 mm, the casting temperature is 700 - 720 °C, and the casting speed is 80 - 110 mm / min; Among them, at the beginning of casting, an Al-Ti-B wire is added to the liquid aluminum alloy for grain refinement treatment, and degassing treatment is carried out on the solution during casting.

3. The method according to claim 2, wherein The conditions of the homogenization treatment include: 540 - 550 °C × 5 - 7 h.

4. The method according to claim 2, characterized in that, The conditions of the turning include: the turning thickness is 3 - 6 mm.

5. The method according to claim 2, wherein The extrusion conditions include: an outer diameter of the circumscribed circle of 159 - 161 mm, a cross-sectional area of 945 - 960 mm 2 , an extrusion cylinder diameter of 205 - 215 mm, and an extrusion ratio of 30 - 40.

6. The method according to claim 2, wherein The conditions of the extrusion include: the heating temperature of the extrusion cylinder is 445 - 455 °C, the flat die is used for the die, the heating temperature of the die is 485 - 515 °C, the heating temperature of the head of the cast rod is 490 - 510 °C, the heating temperature of the tail of the cast rod is 480 - 500 °C, and the extrusion speed is 4 - 5.5 m / min.

7. The method according to claim 2, characterized in that The conditions of the quenching include: the water cooling speed is 3 - 5 m / min, the outlet temperature is 510 - 530 °C. After quenching, online stretching is carried out, the stretching amount is 0.8 - 1.2%, and after stretching, the head and tail are cut off, 0.5 - 0.6 m of the head is removed, and 1.5 - 1.6 m of the tail is removed.

8. The method according to claim 2, wherein The conditions of the heat treatment include: the heat treatment system is T4 heat treatment + annealing at 295 - 305 °C × 2.5 - 3.5 h + single-stage aging at 255 - 265 °C × 3 - 19 h.

Images