High-conductivity high-strength heat-resistant aluminum alloy wire and preparation method thereof

Abstract

The invention discloses a high-conductivity high-strength heat-resistant aluminum alloy wire and a preparation method thereof, and the high-conductivity high-strength heat-resistant aluminum alloy wire comprises the following elements in percentage by mass: 0.02-0.04% of zirconium, 0.3-0.5% of iron, 0.15-0.4% of copper, 0.03-0.06% of magnesium, 0.01-0.03% of boron, less than 0.07% of silicon, less than 0.005% of zinc, less than 0.005% of nickel and the balance of aluminum. The sum of the contents of the manganese, the titanium, the vanadium and the chromium is smaller than or equal to 0.004%, and the total amount of impurity elements except the aluminum, the zirconium, the iron, the copper, the magnesium and the boron is smaller than 0.10%. According to the high-conductivity high-strength heat-resistant aluminum alloy wire, the electric conductivity ranges from 58.5% to 61.5% IACS, the tensile strength ranges from 230 MPa to 270 MPa, the elongation ranges from 2% to 4%, and the strength residual rate after heat preservation is conducted for 1 h at the temperature of 230 DEG C or conducted for 400 h at the temperature of 180 DEG C is 90% or above. The allowed continuous operation temperature of an overhead conductor prepared by using the high-conductivity high-strength heat-resistant aluminum alloy wire as a conductor material is 150 DEG C. The overhead conductor can meet the requirements of a long-span power transmission line and has an excellent energy-saving characteristic.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrical alloy materials, and particularly relates to a high-conductivity high-strength heat-resistant aluminum alloy wire and a preparation method thereof. BACKGROUND

[0002] The heat-resistant aluminum alloy wire that has been maturely applied in overhead transmission lines mainly includes three types: the first type is the ordinary heat-resistant aluminum alloy wire of the NRLH1 type with a continuous operation temperature of 150 DEG C, the electrical conductivity of which is about 60% IACS, and the tensile strength thereof ranges from 159 MPa to 169 MPa; the second type is the high-strength heat-resistant aluminum alloy wire of the NRLH2 type with a continuous operation temperature of 150 DEG C, the electrical conductivity of which is about 55% IACS, and the tensile strength thereof ranges from 225 MPa to 248 MPa; and the third type is the super heat-resistant aluminum alloy wire of the NRLH3 type with a continuous operation temperature of 210 DEG C, the electrical conductivity of which is about 60% IACS, and the tensile strength thereof ranges from 159 MPa to 176 MPa. In the above three types of heat-resistant aluminum alloy wires, the heat-resistant aluminum alloy wires of the NRLH1 type and the NRLH3 type are generally used in the capacity-increasing lines with a small span, and the requirement for the carrying capacity of the heat-resistant aluminum alloy wires is relatively low; and the heat-resistant aluminum alloy wire of the NRLH2 type is generally used in the large-span lines with a span greater than 1000 meters, and in these occasions, the heat-resistant aluminum alloy wire as the conductor material needs to have a high carrying capacity at normal temperature and under the operation condition to meet the requirement for the safety distance to the ground.

[0003] At present, most of the heat-resistant aluminum alloy wires in overhead transmission lines are prepared by adding a proper amount of zirconium element into a pure aluminum matrix to improve the heat resistance of the aluminum material, and the essential principle is that the zirconium and aluminum form an intermediate phase with a L12 crystal structure, which can hinder the dislocation movement under high temperature conditions and improve the mechanical properties of the aluminum material under high temperature environment, but the zirconium element will have a significant negative impact on the electrical conductivity of the aluminum material, and the aluminum material with low electrical conductivity will greatly increase the power transmission loss of the line and also cause the operation temperature of the line to rise and the distance to the ground to decrease, thereby affecting the safe operation of the line.

[0004] There is certain research on the heat-resistant aluminum alloy wires of the NRLH1 type and the NRLH3 type with relatively low strength at home and abroad, but there is relatively less research on the heat-resistant aluminum alloy wire of the NRLH2 type with high strength. The patent CN1941222A discloses a method for manufacturing a high-strength heat-resistant aluminum alloy wire, and the electrical conductivity of the prepared high-strength heat-resistant aluminum alloy wire is not less than 53.0% IACS, which is relatively low. The electrical conductivity of the currently widely used heat-resistant aluminum alloy wire of the NRLH2 type is also only about 55.0% IACS, which is far lower than the electrical conductivity of the aluminum material in conventional transmission lines, and the power transmission loss of the line is very large when the heat-resistant aluminum alloy wire is used in overhead transmission lines.

[0005] Therefore, how to improve the electrical conductivity of the existing NRLH2 type high-strength heat-resistant aluminum alloy wire and realize industrialized production at a lower cost has become a problem to be solved in the application of large-span power transmission line engineering. SUMMARY

[0006] In view of the defects of the prior art, the present application provides a high-conductivity high-strength heat-resistant aluminum alloy wire and a preparation method thereof. An overhead conductor prepared by using the high-conductivity high-strength heat-resistant aluminum alloy wire as a conductor material has a continuous operation temperature of 150 DEG C. The overhead conductor can meet the requirements of large-span power transmission line and has excellent energy-saving characteristics.

[0007] The technical solution adopted by the present application to solve the technical problems is as follows:

[0008] A high-conductivity high-strength heat-resistant aluminum alloy wire is composed of the following elements with mass percentages: 0.02-0.04% of zirconium, 0.3-0.5% of iron, 0.15-0.4% of copper, 0.03-0.06% of magnesium, 0.01-0.03% of boron, <0.07% of silicon, <0.005% of zinc, <0.005% of nickel, the sum of the contents of manganese, titanium, vanadium and chromium being less than or equal to 0.004%, and the total amount of impurity elements other than aluminum, zirconium, iron, copper, magnesium and boron being less than 0.10%, and the rest being aluminum. The electrical conductivity of the high-conductivity high-strength heat-resistant aluminum alloy wire ranges from 58.5% to 61.5% IACS, the tensile strength ranges from 230 MPa to 270 MPa, the elongation ranges from 2% to 4%, and the strength residual rate after 1 h at 230 DEG C or 400 h at 180 DEG C is more than 90%.

[0009] Further, the zirconium is 0.02%, the iron is 0.5%, the copper is 0.4%, the magnesium is 0.04%, the boron is 0.015%, the silicon is <0.07%, and the sum of the contents of manganese, titanium, vanadium and chromium is less than or equal to 0.004%.

[0010] Further, the zirconium is 0.03%, the iron is 0.4%, the copper is 0.3%, the magnesium is 0.05%, the boron is 0.01%, the silicon is <0.07%, and the sum of the contents of manganese, titanium, vanadium and chromium is less than or equal to 0.004%.

[0011] Further, the zirconium is 0.04%, the iron is 0.3%, the copper is 0.2%, the magnesium is 0.06%, the boron is 0.01%, the silicon is <0.07%, and the sum of the contents of manganese, titanium, vanadium and chromium is less than or equal to 0.004%.

[0012] A preparation method of a high-conductivity high-strength heat-resistant aluminum alloy wire includes the following steps:

[0013] S1, melting an aluminum ingot to obtain an aluminum melt;

[0014] S2, adding aluminum-boron intermediate alloy into the aluminum melt obtained in step S1 and stirring to obtain a first aluminum alloy melt, and removing the dross on the surface of the first aluminum alloy melt;

[0015] S3, adding aluminum-zirconium intermediate alloy, aluminum-iron intermediate alloy, aluminum-copper intermediate alloy and pure magnesium ingot into the first aluminum alloy melt after removing the dross in step S2, and stirring to obtain a second aluminum alloy melt;

[0016] S4, refining the second aluminum alloy melt obtained in step S3, and removing the dross on the surface of the second aluminum alloy melt after the refining is completed;

[0017] S5, continuously casting the second aluminum alloy melt treated in step S4 to obtain a heat-resistant aluminum alloy cast strip;

[0018] S6, rolling the heat-resistant aluminum alloy cast strip obtained in step S5 to obtain a heat-resistant aluminum alloy rod blank;

[0019] S7, heat treating the heat-resistant aluminum alloy rod blank obtained in step S6, wherein the temperature of the heat treatment is 150-190℃ and the time is 1-2h, to obtain a high-conductivity high-strength heat-resistant aluminum alloy rod blank;

[0020] S8, continuously drawing the high-conductivity high-strength heat-resistant aluminum alloy rod blank obtained in step S7 using a wire drawing machine to obtain a high-conductivity high-strength heat-resistant aluminum alloy wire.

[0021] Further,

[0022] Step S1 specifically includes: melting aluminum ingots in a smelting furnace to obtain an aluminum melt, transferring the aluminum melt to a holding furnace, and adjusting the temperature of the aluminum melt to 720-750℃.

[0023] Step S4 specifically includes: using high-purity nitrogen gas to spray powder refining agent to refine the second aluminum alloy melt obtained in step S3 and stir, and removing the dross on the surface of the second aluminum alloy melt after the refining is completed.

[0024] Further,

[0025] Further, between step S4 and step S5, the following steps are included: placing the second aluminum alloy melt treated in step S4 for 30-60min, keeping the temperature of the second aluminum alloy melt between 730-750℃, and then sampling and analyzing to confirm that the mass percentage of each element in the second aluminum alloy melt meets the requirements;

[0026] The step S5 is specifically: pouring the second aluminum alloy melt after the standing treatment into a flow guide groove, filtering the second aluminum alloy melt in the flow guide groove by using a foamed ceramic, and performing electromagnetic stirring and purification treatment, and adjusting the temperature of the melt after the purification treatment, when the temperature is adjusted to 740-760 DEG C, transferring the melt to a wheel type casting machine for continuous casting, and obtaining a heat-resistant aluminum alloy cast strip with a cross-sectional area of 1600-3000 mm 2 .

[0027] Further, the step S6 is specifically: keeping the rolling-in temperature of the heat-resistant aluminum alloy cast strip obtained in the step S5 at 450-510 DEG C, and then entering a rolling mill for rolling to obtain a heat-resistant aluminum alloy rod blank with a diameter of 9-12 mm.

[0028] Further, the step S8 is specifically: using a sliding type wire drawing machine or a non-sliding type wire drawing machine to continuously draw the high-conductivity high-strength heat-resistant aluminum alloy rod blank obtained in the step S7, wherein the wire drawing speed of the continuous drawing is 5-15 m / s, and the cross-sectional change rate of each pass is 13-17%, until the high-conductivity high-strength heat-resistant aluminum alloy wire rod with a required specification is drawn.

[0029] Further, in the step S8: the diameter of the high-conductivity high-strength heat-resistant aluminum alloy wire rod drawn is 2-6 mm.

[0030] Compared with the prior art, the beneficial effects of the present application are:

[0031] The high-conductivity high-strength heat-resistant aluminum alloy wire in the present application is composed of the following elements in mass percentage: 0.02-0.04% of zirconium, 0.3-0.5% of iron, 0.15-0.4% of copper, 0.03-0.06% of magnesium, 0.01-0.03% of boron, <0.07% of silicon, <0.005% of zinc, <0.005% of nickel, the sum of manganese, titanium, vanadium and chromium being less than or equal to 0.004%, and the total amount of impurity elements other than aluminum, zirconium, iron, copper, magnesium and boron being less than 0.10%, and the rest being aluminum. The strength residual rate of the high-conductivity high-strength heat-resistant aluminum alloy wire after being kept at 230°C for 1h or after being kept at 180°C for 400h is more than 90%. The allowable continuous operating temperature of the overhead conductor prepared by using the high-conductivity high-strength heat-resistant aluminum alloy wire as the conductor material is 150°C, which meets the safety operation requirement of the high-strength heat-resistant aluminum alloy wire transmission line of the NRLH2 type. The conductivity of the high-conductivity high-strength heat-resistant aluminum alloy wire ranges from 58.5% to 61.5% IACS, while the conductivity of the existing high-strength heat-resistant aluminum alloy wire of the NRLH2 type in the background technology is about 55% IACS. Therefore, the conductivity of the high-conductivity high-strength heat-resistant aluminum alloy wire is superior to that of the existing high-strength heat-resistant aluminum alloy wire of the NRLH2 type in the background technology. Thus, the overhead conductor prepared by using the high-conductivity high-strength heat-resistant aluminum alloy wire has excellent energy-saving characteristics during operation. In addition, the tensile strength of the high-conductivity high-strength heat-resistant aluminum alloy wire ranges from 230MPa to 270MPa, and the elongation ranges from 2% to 4%. Therefore, the overhead conductor prepared by using the high-conductivity high-strength heat-resistant aluminum alloy wire can meet the requirement of large-span transmission line.

[0032] The present application adds appropriate elements in a specific proportion to a pure aluminum matrix, and after the processes of alloy smelting, continuous casting, rolling, heat treatment and continuous drawing, a heat-resistant aluminum alloy wire with a conductivity much higher than the standard and a strength meeting the requirement is finally obtained. The method of the present application can realize the industrialized production of high-conductivity high-strength heat-resistant aluminum alloy wire at a lower cost. DETAILED DESCRIPTION

[0033] The high-conductivity high-strength heat-resistant aluminum alloy wire is composed of the following elements in mass percentage: 0.02-0.04% of zirconium, 0.3-0.5% of iron, 0.15-0.4% of copper, 0.03-0.06% of magnesium, 0.01-0.03% of boron, <0.07% of silicon, <0.005% of zinc, <0.005% of nickel, the sum of manganese, titanium, vanadium and chromium being less than or equal to 0.004%, and the total amount of impurity elements other than aluminum, zirconium, iron, copper, magnesium and boron being less than 0.10%, and the rest being aluminum; the conductivity of the high-conductivity high-strength heat-resistant aluminum alloy wire ranges from 58.5% to 61.5% IACS, the tensile strength ranges from 230 MPa to 270 MPa, the elongation ranges from 2% to 4%, and the strength residual rate after 1 h at 230 DEG C or 400 h at 180 DEG C is above 90%.

[0034] The preparation method of the high-conductivity high-strength heat-resistant aluminum alloy wire comprises the following steps:

[0035] S1, melting aluminum ingot in a melting furnace to obtain aluminum melt, and transferring the aluminum melt to a holding furnace to adjust the temperature of the aluminum melt to 720-750 DEG C;

[0036] S2, adding aluminum-boron intermediate alloy to the aluminum melt obtained in step S1 and stirring to obtain a first aluminum alloy melt, and removing the dross on the surface of the first aluminum alloy melt;

[0037] S3, adding aluminum-zirconium intermediate alloy, aluminum-iron intermediate alloy, aluminum-copper intermediate alloy and pure magnesium ingot to the first aluminum alloy melt after removing the dross in step S2, and stirring to obtain a second aluminum alloy melt;

[0038] S4, refining the second aluminum alloy melt obtained in step S3 by using high-purity nitrogen gas to spray powder refining agent and stirring, and removing the dross on the surface of the second aluminum alloy melt after the refining is completed;

[0039] S5, placing the second aluminum alloy melt treated in step S4 for 30-60 min, keeping the temperature of the second aluminum alloy melt between 730 DEG C and 750 DEG C, and then sampling and analyzing to confirm that the mass percentage of each element in the second aluminum alloy melt meets the requirements;

[0040] S6, pouring the second aluminum alloy melt treated by standing into a flow guide groove, filtering the second aluminum alloy melt by using foam ceramic in the flow guide groove, and performing electromagnetic stirring and purification treatment, and adjusting the temperature of the melt after purification treatment, when the temperature is adjusted to 740 DEG C-760 DEG C, transferring the melt to a wheel-type casting machine for continuous casting to obtain a heat-resistant aluminum alloy cast strip with a cross-sectional area of 1600-3000 mm 2 .

[0041] S7, the temperature of the heat-resistant aluminum alloy bar obtained in step S6 is kept at 450-510℃, and then the bar is put into a rolling mill to be rolled to obtain a heat-resistant aluminum alloy rod with a diameter of 9-12mm;

[0042] S8, the heat-resistant aluminum alloy rod obtained in step S7 is heat treated at a temperature of 150-190℃ for 1-2h to obtain a high-conductivity high-strength heat-resistant aluminum alloy rod;

[0043] S9, the high-conductivity high-strength heat-resistant aluminum alloy rod obtained in step S8 is continuously drawn by using a sliding type wire drawing machine or a non-sliding type wire drawing machine, wherein the drawing speed is 5-15m / s, and the section change rate of each pass is 13-17%, until the high-conductivity high-strength heat-resistant aluminum alloy wire with a required specification is drawn. Preferably, the diameter of the drawn high-conductivity high-strength heat-resistant aluminum alloy wire is 2-6mm.

[0044] By adding suitable elements in a specific proportion to a pure aluminum matrix, and through the processes of alloy smelting, continuous casting, rolling, heat treatment and continuous drawing, the present application finally obtains a heat-resistant aluminum alloy wire with a conductivity much higher than the standard and a strength meeting the requirements, and the industrialized production of the high-conductivity high-strength heat-resistant aluminum alloy wire can be realized at a lower cost by using the method of the present application.

[0045] The strength residual rate of the high-conductivity high-strength heat-resistant aluminum alloy wire prepared by the present application is above 90% after being kept at 230℃ for 1h or after being kept at 180℃ for 400h, the allowable continuous operating temperature of the overhead conductor prepared by using the high-conductivity high-strength heat-resistant aluminum alloy wire as a conductor material is 150℃, which meets the safety operation requirements of the NRLH2 type high-strength heat-resistant aluminum alloy wire transmission line; the conductivity of the high-conductivity high-strength heat-resistant aluminum alloy wire ranges from 58.5% to 61.5% IACS, while the conductivity of the existing NRLH2 type high-strength heat-resistant aluminum alloy wire in the background art is about 55% IACS, so the conductivity performance of the high-conductivity high-strength heat-resistant aluminum alloy wire is superior to that of the existing NRLH2 type high-strength heat-resistant aluminum alloy wire in the background art, and therefore the overhead conductor prepared by using the high-conductivity high-strength heat-resistant aluminum alloy wire has excellent energy-saving characteristics during operation; and since the tensile strength of the high-conductivity high-strength heat-resistant aluminum alloy wire ranges from 230MPa to 270MPa and the elongation rate ranges from 2% to 4%, the overhead conductor prepared by using the high-conductivity high-strength heat-resistant aluminum alloy wire can meet the high bearing capacity requirements in large-span transmission lines.

[0046] In the application, by setting the mass percentage content of zirconium element between 0.02-0.04%, the negative influence of zirconium element on the conductivity of the prepared high-conductivity high-strength heat-resistant aluminum alloy wire is small, the conductivity of the high-conductivity high-strength heat-resistant aluminum alloy wire can be kept between 58.5-61.5% IACS, dislocation movement can be hindered under high temperature conditions, and the mechanical properties of the high-conductivity high-strength heat-resistant aluminum alloy wire under high temperature environment can be improved, the tensile strength of the high-conductivity high-strength heat-resistant aluminum alloy wire can reach 230-270 MPa, the elongation can reach 2-4%, and the strength residual rate after keeping at 230℃ for 1h or after keeping at 180℃ for 400h is more than 90%.

[0047] In the application, the high strength of the heat-resistant aluminum alloy wire is ensured by adding appropriate amounts of iron element and copper element, and the mass percentage contents of the iron element and the copper element are strictly limited, the iron is 0.3-0.5%, and the copper is 0.15-0.4%. The appropriate amounts of iron element and copper element can be dissolved in the aluminum matrix, can significantly improve the mechanical properties of the aluminum matrix, and will not significantly reduce the conductivity of the heat-resistant aluminum alloy wire, and the appropriate amount of copper element can improve the processing toughness of the aluminum matrix material.

[0048] In the application, a small amount of magnesium element and boron element are also added, the mass percentage content of the magnesium element is 0.03-0.06%, and the mass percentage content of the boron element is 0.01-0.03%. The magnesium element and the boron element are mainly used to improve the processing performance of the aluminum alloy in the continuous casting and rolling process and refine the grain structure. The magnesium element can also improve the strength of the aluminum matrix, and the boron element can form compounds with impurity elements such as manganese, titanium, vanadium and chromium in the aluminum alloy melt which have a significant negative impact on the conductivity of the aluminum matrix, and effectively remove the impurity elements such as manganese, titanium, vanadium and chromium.

[0049] In the application, other elements are all inevitable impurity elements in the aluminum matrix. In order to ensure the high conductivity of the heat-resistant aluminum alloy wire, the mass percentage contents of the elements are limited, the silicon is less than 0.07%, the zinc is less than 0.005%, the nickel is less than 0.005%, the sum of the contents of manganese, titanium, vanadium and chromium is less than or equal to 0.004%, and the total amount of impurity elements other than aluminum, zirconium, iron, copper, magnesium and boron is less than 0.10%.

[0050] Example 1

[0051] The application discloses a high-conductivity high-strength heat-resistant aluminum alloy wire rod, which is composed of the following elements in percentage by mass: 0.02% of zirconium, 0.5% of iron, 0.4% of copper, 0.04% of magnesium, 0.015% of boron, less than 0.07% of silicon, less than 0.005% of zinc, less than 0.005% of nickel, less than or equal to 0.004% of the sum of manganese, titanium, vanadium and chromium, and less than 0.10% of impurities except aluminum, zirconium, iron, copper, magnesium and boron.

[0052] The application further discloses a preparation method of the high-conductivity high-strength heat-resistant aluminum alloy wire rod.

[0053] S1, according to the preparation of 2 tons of aluminum liquid, an electrician aluminum ingot with a brand of Al99.85 is melted in a smelting furnace to obtain an aluminum melt, the aluminum melt is transferred to a holding furnace, and the temperature of the aluminum melt is adjusted to 730 DEG C.

[0054] S2, 10 kg of aluminum-boron intermediate alloy is added to the holding furnace for boronizing treatment and is fully stirred to obtain a first aluminum alloy melt, and the dross on the surface of the first aluminum alloy melt is removed, wherein the aluminum-boron intermediate alloy is represented as AlB3, and the mass percentage of B in the AlB3 intermediate alloy is 3%.

[0055] S3, 8 kg of aluminum-zirconium intermediate alloy, 200 kg of aluminum-iron intermediate alloy, 16 kg of aluminum-copper intermediate alloy and 0.8 kg of pure magnesium ingot are sequentially added to the holding furnace and are fully stirred to obtain a second aluminum alloy melt, and the temperature of the second aluminum alloy melt is adjusted to 740 DEG C, wherein the aluminum-zirconium intermediate alloy is represented as AlZr5, the mass percentage of Zr in the AlZr5 intermediate alloy is 5%; wherein the aluminum-iron intermediate alloy is represented as AlFe5, the mass percentage of Fe in the AlFe5 intermediate alloy is 5%, wherein the aluminum-copper intermediate alloy is represented as AlCu50, and the mass percentage of Cu in the AlCu50 intermediate alloy is 50%.

[0056] S4, 0.1 kg of 45% KCl-30% NaCl-25% Na3AlF6 refining agent is sprayed into the holding furnace by using high-purity nitrogen, the second aluminum alloy melt obtained in the step S3 is refined and stirred, and the dross on the surface of the second aluminum alloy melt is removed after the refining is completed.

[0057] S5, the second aluminum alloy melt after the treatment in the step S4 is placed for 30 min, the temperature of the second aluminum alloy melt is kept above 720 DEG C, and then sampling analysis is carried out to confirm that the mass percentage of each element in the second aluminum alloy melt meets the requirements of the embodiment.

[0058] S6, pour the second aluminum alloy melt after the standing treatment in the holding furnace into a flow guide groove, filter the second aluminum alloy melt in the flow guide groove using a foamed ceramic, and perform electromagnetic stirring and purification treatment, and adjust the temperature of the melt after the purification treatment, when the temperature is adjusted to 740-760℃, transfer the melt to a wheel type casting machine for continuous casting to obtain a heat-resistant aluminum alloy cast strip with a cross-sectional area of 3000mm 2 ;

[0059] S7, keep the rolling-in temperature of the heat-resistant aluminum alloy cast strip obtained in step S6 at 450-500℃, and then enter the rolling mill for rolling to obtain a heat-resistant aluminum alloy rod blank with a diameter of 12mm;

[0060] S8, heat treatment is performed on the heat-resistant aluminum alloy rod blank obtained in step S7, wherein the temperature of the heat treatment is 160℃ and the time is 2h, to obtain a high-conductivity high-strength heat-resistant aluminum alloy rod blank;

[0061] S9, continuously draw the high-conductivity high-strength heat-resistant aluminum alloy rod blank obtained in step S8 using a non-sliding wire drawing machine, wherein the wire drawing speed of the continuous drawing is 12m / s, and the cross-sectional change rate of each pass is 17%, to obtain a high-conductivity high-strength heat-resistant aluminum alloy wire with a diameter of 4mm.

[0062] The prepared high-conductivity high-strength heat-resistant aluminum alloy wire with a diameter of 4mm has an electrical conductivity of 61.5%IACS, a tensile strength of 240MPa, an elongation of 3%, and an intensity residual rate of 91.0% after 1h of heat preservation at 230℃.

[0063] Example 2

[0064] A high-conductivity high-strength heat-resistant aluminum alloy wire, which is composed of the following mass percentage of elements: zirconium 0.03%, iron 0.4%, copper 0.3%, magnesium 0.05%, boron 0.01%, silicon <0.07%, zinc <0.005%, nickel <0.005%, the sum of manganese, titanium, vanadium and chromium is less than or equal to 0.004%, and the total amount of impurity elements other than aluminum, zirconium, iron, copper, magnesium and boron is less than 0.10%, and the rest is aluminum.

[0065] The preparation method of the high-conductivity high-strength heat-resistant aluminum alloy wire comprises the following steps:

[0066] S1, according to the preparation of 2 tons of aluminum liquid, melt the electrician aluminum ingot with a brand of Al99.85 in a melting furnace to obtain an aluminum melt, transfer the aluminum melt to a holding furnace, and adjust the temperature of the aluminum melt to 735℃;

[0067] S2, 7 kg of aluminum-boron intermediate alloy is added to the holding furnace for boronizing treatment and fully stirred to obtain a first aluminum alloy melt, and the dross on the surface of the first aluminum alloy melt is removed, wherein the aluminum-boron intermediate alloy is represented by AlB3, and the mass percentage of B element in the AlB3 intermediate alloy is 3%;

[0068] S3, 12 kg of aluminum-zirconium intermediate alloy, 160 kg of aluminum-iron intermediate alloy, 12 kg of aluminum-copper intermediate alloy and 1 kg of pure magnesium ingot are sequentially added to the holding furnace and fully stirred to obtain a second aluminum alloy melt, and the temperature of the second aluminum alloy melt is adjusted to 740℃, wherein the aluminum-zirconium intermediate alloy is represented by AlZr5, and the mass percentage of Zr element in the AlZr5 intermediate alloy is 5%; wherein the aluminum-iron intermediate alloy is represented by AlFe5, and the mass percentage of Fe element in the AlFe5 intermediate alloy is 5%, wherein the aluminum-copper intermediate alloy is represented by AlCu50, and the mass percentage of Cu element in the AlCu50 intermediate alloy is 50%;

[0069] S4, 0.1 kg of 45% KCl-30% NaCl-25% Na3AlF6 refining agent is sprayed into the holding furnace using high-purity nitrogen to refine the second aluminum alloy melt obtained in step S3 and stir, and after the refining is completed, the dross on the surface of the second aluminum alloy melt is removed;

[0070] S5, the second aluminum alloy melt after step S4 is placed for 30 min, and the temperature of the second aluminum alloy melt is kept above 730℃, then sampling analysis is carried out to confirm that the mass percentage of each element in the second aluminum alloy melt meets the requirements of the present embodiment;

[0071] S6, the second aluminum alloy melt after standing treatment in the holding furnace is poured into a flow guide groove, the second aluminum alloy melt is filtered in the flow guide groove using foam ceramic, and electromagnetic stirring and purification treatment are carried out, and the temperature of the melt after purification treatment is adjusted, when the temperature is adjusted to 740-760℃, the melt is transferred to a wheel type casting machine for continuous casting to obtain a heat-resistant aluminum alloy cast strip with a cross-sectional area of 2500mm 2 ;

[0072] S7, the rolling-in temperature of the heat-resistant aluminum alloy cast strip obtained in step S6 is kept at 475-500℃, then it enters the rolling mill for rolling to obtain a heat-resistant aluminum alloy rod blank with a diameter of 9.5mm;

[0073] S8, the heat-resistant aluminum alloy rod blank obtained in step S7 is heat treated, wherein the heat treatment temperature is 170℃ and the time is 2h, to obtain a high-conductivity high-strength heat-resistant aluminum alloy rod blank;

[0074] S9, the high-conductivity high-strength heat-resistant aluminum alloy rod blank obtained in step S8 is continuously drawn by using a non-sliding wire drawing machine, wherein the wire drawing speed of the continuous drawing is 10 m / s, the cross-section change rate of each pass is 17%, and a high-conductivity high-strength heat-resistant aluminum alloy wire with a diameter of 3 mm is obtained.

[0075] The prepared high-conductivity high-strength heat-resistant aluminum alloy wire with a diameter of 3 mm has an electrical conductivity of 60% IACS, a tensile strength of 260 MPa, an elongation of 2%, and an intensity residual rate of 92.0% after 1 h of heat preservation at 230℃.

[0076] Example 3

[0077] A high-conductivity high-strength heat-resistant aluminum alloy wire is composed of the following elements with mass percentages: 0.04% of zirconium, 0.3% of iron, 0.2% of copper, 0.06% of magnesium, 0.01% of boron, less than 0.07% of silicon, less than 0.005% of zinc, less than 0.005% of nickel, the sum of manganese, titanium, vanadium and chromium being less than or equal to 0.004%, and the total amount of impurity elements other than aluminum, zirconium, iron, copper, magnesium and boron being less than 0.10%, and the rest being aluminum.

[0078] A method for preparing the high-conductivity high-strength heat-resistant aluminum alloy wire comprises the following steps:

[0079] S1, according to the preparation of 2 tons of aluminum liquid, the Al99.85 grade electrical aluminum ingot is melted in a melting furnace to obtain an aluminum melt, and the temperature of the aluminum melt is adjusted to 750℃, and then the aluminum melt is transferred to a holding furnace;

[0080] S2, 7 kg of aluminum-boron intermediate alloy is added to the holding furnace for boronizing treatment and fully stirred to obtain a first aluminum alloy melt, and the dross on the surface of the first aluminum alloy melt is removed, wherein the aluminum-boron intermediate alloy is represented by AlB3, and the mass percentage of B element in the AlB3 intermediate alloy is 3%;

[0081] S3, 16 kg of aluminum-zirconium intermediate alloy, 120 kg of aluminum-iron intermediate alloy, 8 kg of aluminum-copper intermediate alloy and 1.2 g of pure magnesium ingot are sequentially added to the holding furnace and fully stirred to obtain a second aluminum alloy melt, and the temperature of the second aluminum alloy melt is adjusted to 740℃, wherein the aluminum-zirconium intermediate alloy is represented by AlZr5, and the mass percentage of Zr element in the AlZr5 intermediate alloy is 5%; wherein the aluminum-iron intermediate alloy is represented by AlFe5, and the mass percentage of Fe element in the AlFe5 intermediate alloy is 5%; wherein the aluminum-copper intermediate alloy is represented by AlCu50, and the mass percentage of Cu element in the AlCu50 intermediate alloy is 50%;

[0082] S4, 0.1 kg of 45% KCl-30% NaCl-25% Na3AlF6refining agent is sprayed into the holding furnace by using high-purity nitrogen, the second aluminum alloy melt obtained in step S3 is refined and stirred, and after the refining is completed, the dross on the surface of the second aluminum alloy melt is removed;

[0083] S5, the second aluminum alloy melt treated in step S4 is left for 30 min, and the temperature of the second aluminum alloy melt is kept above 740°C, then sampling analysis is carried out, and it is confirmed that the mass percentage of each element in the second aluminum alloy melt meets the requirements of the present embodiment;

[0084] S6, the second aluminum alloy melt treated by standing in the holding furnace is poured into a flow guide groove, the second aluminum alloy melt is filtered by using foamed ceramic in the flow guide groove, and electromagnetic stirring and purification treatment are carried out, and the temperature of the melt after purification treatment is adjusted, when the temperature is adjusted to 740-760°C, the melt is transferred to a wheel type casting machine for continuous casting, and a heat-resistant aluminum alloy cast strip with a cross-sectional area of 2000mm 2 is obtained;

[0085] S7, the rolling-in temperature of the heat-resistant aluminum alloy cast strip obtained in step S6 is kept at 480-510°C, then it is rolled into a rolling mill to obtain a heat-resistant aluminum alloy rod blank with a diameter of 9.5mm;

[0086] S8, the heat-resistant aluminum alloy rod blank obtained in step S7 is heat treated, wherein the heat treatment temperature is 180°C and the time is 2h, and a high-conductivity high-strength heat-resistant aluminum alloy rod blank is obtained;

[0087] S9, the high-conductivity high-strength heat-resistant aluminum alloy rod blank obtained in step S8 is continuously drawn by using a non-sliding wire drawing machine, wherein the wire drawing speed of continuous drawing is 10m / s, and the cross-sectional change rate of each pass is 17%, and a high-conductivity high-strength heat-resistant aluminum alloy wire with a diameter of 3.5mm is obtained.

[0088] The prepared high-conductivity high-strength heat-resistant aluminum alloy wire with a diameter of 3.5mm has an electrical conductivity of 59% IACS, a tensile strength of 270Pa, an elongation of 2%, and a strength residual rate of 92.0% after 230°C holding for 1h.

[0089] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, without departing from the technical principles of the present application, a number of improvements and substitutions can be made, and these improvements and substitutions should also be considered as the protection scope of the present application.

Claims

1. A high-conductivity high-strength heat-resistant aluminum alloy wire, characterized by comprising, in mass %, 0.02-0.04% of zirconium, 0.3-0.5% of iron, 0.15-0.4% of copper, 0.03-0.06% of magnesium, 0.01-0.03% of boron, <0.07% of silicon, <0.005% of zinc, <0.005% of nickel, the sum of the contents of manganese, titanium, vanadium and chromium being less than or equal to 0.004%, and the total amount of impurity elements other than aluminum, zirconium, iron, copper, magnesium and boron being less than 0.10%, and the rest being aluminum; the high-conductivity high-strength heat-resistant aluminum alloy wire has an electrical conductivity ranging from 58.5% to 61.5% IACS, a tensile strength ranging from 230 MPa to 270 MPa, an elongation ranging from 2% to 4%, and a strength residual rate of more than 90% after being kept at 230℃ for 1h or after being kept at 180℃ for 400h.

2. The high-conductivity high-strength heat-resistant aluminum alloy wire of claim 1, wherein: 0.02% of zirconium, 0.5% of iron, 0.4% of copper, 0.04% of magnesium, 0.015% of boron, <0.07% of silicon, and the sum of the contents of manganese, titanium, vanadium and chromium being less than or equal to 0.004%.

3. The high-conductivity high-strength heat-resistant aluminum alloy wire of claim 1, wherein: 0.03% of zirconium, 0.4% of iron, 0.3% of copper, 0.05% of magnesium, 0.01% of boron, <0.07% of silicon, and the sum of the contents of manganese, titanium, vanadium and chromium being less than or equal to 0.004%.

4. The high-conductivity high-strength heat-resistant aluminum alloy wire of claim 1, wherein: 0.04% of zirconium, 0.3% of iron, 0.2% of copper, 0.06% of magnesium, 0.01% of boron, <0.07% of silicon, and the sum of the contents of manganese, titanium, vanadium and chromium being less than or equal to 0.004%.

5. A method for preparing a high-conductivity, high-strength, heat-resistant aluminum alloy wire according to any one of claims 1-4, characterized in that, The method comprises the following steps: S1, melting aluminum ingots to obtain an aluminum melt; S2, adding an aluminum-boron intermediate alloy to the aluminum melt obtained in step S1 and stirring to obtain a first aluminum alloy melt, and removing dross on the surface of the first aluminum alloy melt; S3, adding an aluminum-zirconium intermediate alloy, an aluminum-iron intermediate alloy, an aluminum-copper intermediate alloy and pure magnesium ingots to the first aluminum alloy melt after removing the dross in step S2 and stirring to obtain a second aluminum alloy melt; S4, refining the second aluminum alloy melt obtained in step S3, and removing dross on the surface of the second aluminum alloy melt after the refining is completed; S5, continuously casting the second aluminum alloy melt treated in step S4 to obtain a heat-resistant aluminum alloy cast strip; S6, rolling the heat-resistant aluminum alloy cast strip obtained in step S5 to obtain a heat-resistant aluminum alloy rod blank; S7, heat treating the heat-resistant aluminum alloy rod blank obtained in step S6, wherein the heat treatment is performed at a temperature of 150-190℃ and for a time of 1-2h to obtain a high-conductivity high-strength heat-resistant aluminum alloy rod blank; S8, continuously drawing the high-conductivity high-strength heat-resistant aluminum alloy rod blank obtained in step S7 by using a wire drawing machine to obtain a high-conductivity high-strength heat-resistant aluminum alloy wire.

6. The method according to claim 5, wherein step S1 is specifically melting aluminum ingots in a melting furnace to obtain an aluminum melt, and transferring the aluminum melt to a holding furnace and adjusting the temperature of the aluminum melt to 720-750℃. ​ The step S4 specifically comprises: using high-purity nitrogen gas to spray the powder refining agent to refine and stir the second aluminum alloy melt obtained in the step S3, and removing the dross on the surface of the second aluminum alloy melt after the refining is completed.

7. The method according to claim 5, wherein the method further comprises the following steps: after the step S4, the second aluminum alloy melt is kept for 30-60 minutes, and the temperature of the second aluminum alloy melt is kept at 730-750 ℃, and then the second aluminum alloy melt is sampled and analyzed to confirm that the mass percentage of each element in the second aluminum alloy melt meets the requirements. The step S4 and the step S5 further comprise the following steps: the second aluminum alloy melt treated in the step S4 is kept for 30-60 minutes, and the temperature of the second aluminum alloy melt is kept at 730-750 ℃, and then the second aluminum alloy melt is sampled and analyzed to confirm that the mass percentage of each element in the second aluminum alloy melt meets the requirements. The step S5 specifically comprises: pouring the second aluminum alloy melt after the standing treatment into a flow guide groove, filtering the second aluminum alloy melt by using a foamed ceramic in the flow guide groove, and performing electromagnetic stirring and purification treatment, and adjusting the temperature of the melt after the purification treatment, when the temperature is adjusted to 740-760 DEG C, transferring the melt to a wheel type casting machine for continuous casting to obtain a heat-resistant aluminum alloy cast strip with a cross-sectional area of 1600-3000 mm 2 .

8. The method for preparing a high-conductivity, high-strength, heat-resistant aluminum alloy wire according to claim 5, characterized in that, The step S6 specifically comprises: the rolling-in temperature of the heat-resistant aluminum alloy cast strip obtained in the step S5 is kept at 450-510 ℃, and then the heat-resistant aluminum alloy cast strip is rolled in a rolling mill to obtain a heat-resistant aluminum alloy rod blank with a diameter of 9-12 mm.

9. The method of claim 5, wherein the high-conductivity high-strength heat-resistant aluminum alloy wire is prepared by the steps of: preparing a high-conductivity high-strength heat-resistant aluminum alloy ingot; homogenizing the ingot; hot extruding the ingot; cold drawing the extruded ingot; and annealing the cold-drawn ingot. The step S8 specifically comprises: using a sliding type wire drawing machine or a non-sliding type wire drawing machine to continuously draw the heat-resistant aluminum alloy rod blank obtained in the step S7, wherein the wire drawing speed of the continuous drawing is 5-15 m / s, and the cross-section change rate of each pass is 13-17%, until the heat-resistant aluminum alloy wire with the required specification is drawn.

10. The method for preparing a high-conductivity, high-strength, heat-resistant aluminum alloy wire according to claim 9, characterized in that, In the step S8, the diameter of the drawn heat-resistant aluminum alloy wire is 2-6 mm.