Preparation method of high-performance heat-resistant aluminum alloy and seamless pipe

Abstract

The invention discloses a high-performance heat-resistant aluminum alloy which comprises the following chemical components in percentage by mass: 4.5 to 6.5 percent of Cu, 0.5 to 2.3 percent of Mg, 0.5 to 1.5 percent of Si, 0.2 to 0.8 percent of Ni, 0.3 to 2.0 percent of Mn, 0.03 to 0.2 percent of Mo, 0.03 to 0.2 percent of Zr, 0.03 to 0.2 percent of Ag, 0.01 to 0.15 percent of Ti, less than or equal to 0.4 percent of Fe, 0.05 to 0.5 percent of La, 0.05 to 0.5 percent of Nd, 0.05 to 0.5 percent of Er, less than or equal to 0.03 percent of other inevitable single impurity elements, less than or equal to 0.15 percent of total impurity elements and the balance of aluminum. The aluminum alloy and the seamless pipe produced from the aluminum alloy have the comprehensive properties of high strength, high plasticity, high toughness and the like, also have excellent high temperature resistance, corrosion resistance and fatigue resistance, and can meet the requirements of long-term safe service under various extreme conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy materials and casting, and specifically relates to a preparation method of a high-performance heat-resistant aluminum alloy and a seamless pipe. Background Art

[0002] Aluminum alloy materials have been widely used in various fields of the national economy due to their low density and moderate mechanical properties. However, traditional aluminum alloy materials have poor heat resistance and are difficult to serve for a long time in an environment above 450°C, which limits the application of aluminum alloy materials in many environments. In the field of geological exploration, in order to obtain deeper drilling depths and faster drilling speeds, and at the same time reduce the risk of corrosion failure caused by underground corrosive media, aluminum alloy materials are needed to produce drill pipes. At present, foreign countries have used aluminum alloys of different grades such as 2014, 2618, and 7075 to produce drill pipes, but they still cannot solve the problem of poor heat resistance, resulting in insufficient service life of the drill pipe. Therefore, it is urgent to develop a new type of aluminum alloy material with excellent room temperature mechanical properties, excellent heat resistance, and good plasticity to meet the urgent demand for high-performance aluminum alloy pipes in the field of geological exploration. Summary of the invention

[0003] In view of the above-mentioned deficiencies, the present invention discloses a high-performance heat-resistant aluminum alloy having good mechanical properties, heat resistance and plasticity. The seamless pipe produced by using the high-performance heat-resistant aluminum alloy can be used as a drill rod for geological exploration, thereby solving the problem of insufficient service life of existing aluminum alloy drill rods.

[0004] The present invention is achieved by adopting the following technical solutions: A high performance heat-resistant aluminum alloy comprising the following chemical components in mass fractions: Cu: 4.5-6.5%, Mg: 0.5-2.3%, Si: 0.5-1.5%, Ni: 0.2-0.8%, Mn: 0.3-2.0%, Mo: 0.03-0.2%, Zr: 0.03-0.2%, Ag: 0.03-0.2%, Ti: 0.01-0.15%, Fe≤0.4%, La: 0.05-0.5%, Nd: 0.05-0.5%, Er: 0.05-0.5%, other unavoidable single impurity elements ≤0.03%, the total amount of impurity elements ≤0.15%, the balance is aluminum.

[0005] The present invention uses Cu, Mg and Si as main alloy elements. On the one hand, they can form a solid solution in the aluminum alloy matrix grains to produce a solid solution strengthening effect; on the other hand, during the artificial aging process, the solute atoms in the supersaturated solid solution are decomposed to form a nanometer-scale precipitation phase, which produces a precipitation strengthening effect.

[0006] At the same time, the added Fe, Mn, and Ni elements can form an intermediate phase with high thermal stability with the Al element, thereby improving the heat resistance of the alloy; the Mo, Zr elements form a series of complex intermediate phases with Al. These intermediate phases are small in size, which, on the one hand, have the effect of refining the grains; on the other hand, because the temperature required for their decomposition is high, they can stably exist at higher temperatures, thereby improving the heat resistance of the alloy material; the Ag element, on the one hand, promotes the precipitation of θ', making the precipitated phase small and evenly distributed; on the other hand, the Ag element is enriched on the θ' surface, hindering the growth of the Cu element in θ' at high temperatures, thereby improving the thermal stability of the θ' phase; the Ti element is added in the flow trough through an aluminum-titanium-boron alloy rod, and its main function is to refine the cast grains of the alloy and avoid the appearance of coarse grains.

[0007] Furthermore, La, Nd and Er used in the present invention are rare earth elements, which can form intermediate phases with Al, and can also form more complex intermediate phases with transition metal elements such as Mo and Zr, thereby refining grains and inhibiting abnormal recrystallization. At the same time, these intermediate phases have high thermal stability, thereby improving the heat resistance of the alloy.

[0008] Furthermore, the high performance heat-resistant aluminum alloy comprises the following chemical components in mass fractions: Cu: 4.6-6.3%, Mg: 0.6-2.0%, Si: 0.6-1.3%, Ni: 0.4-0.6%, Mn: 0.6-1.6%, Mo: 0.05-0.18%, Zr: 0.05-0.18%, Ag: 0.05-0.18%, Ti: 0.01-0.12%, Fe≤0.3%, La: 0.1-0.4%, Nd: 0.1-0.4%, Er: 0.1-0.4%, other unavoidable single impurity elements ≤0.03%, the total amount of impurity elements ≤0.15%, the balance is aluminum.

[0009] Furthermore, the total content of the three elements La, Nd and Er is not less than 0.25% and not more than 0.80%, and the content ratio of the three elements La, Nd and Er is (2-5): (1-4): (1-4). By controlling the content of the three elements La, Nd and Er and the usage ratio of the three elements, they can better form a suitable intermediate phase with Al and transition metal elements such as Mo and Zr, improve the effect of grain refinement and inhibit abnormal recrystallization, and thus improve the heat resistance of aluminum alloy products.

[0010] The method for preparing the high-performance heat-resistant aluminum alloy comprises the following steps: (1) weighing raw materials in proportion, placing aluminum ingot, electrolytic copper, aluminum-nickel master alloy, aluminum-manganese master alloy, aluminum-molybdenum master alloy, aluminum-zirconium master alloy, aluminum-silver master alloy, aluminum-iron master alloy, aluminum-lanthanum master alloy, aluminum-neodymium master alloy, and aluminum-erbium master alloy in a melting furnace and heating them until they are melted, and then melting them at 760-860° C. to obtain a melt A; (2) taking the melt A obtained in step (1) and refining it once at 740-780° C. for 40-70 minutes, and then letting it stand and skimming off the slag to obtain melt B; (3) Adding industrial silicon and magnesium ingots to the melt B obtained in step (2) and smelting the melt at 720-820° C., taking samples from the melt for chemical composition analysis. If the composition is deviated, taking the raw materials in step (1) for composition adjustment and taking samples for analysis again until all elements reach the expected indexes, thereby obtaining melt C; (4) The melt C obtained in step (3) is subjected to secondary refining at 700-760° C. for 20-40 minutes, and then allowed to stand for slagging. Samples are taken from the melt for chemical composition analysis. If the composition is deviated, the raw material in step (1) is adjusted for composition, and then secondary refining is performed again and samples are taken for analysis again until all elements reach the expected indexes to obtain a melt D. The melt D is cast to obtain a high-performance heat-resistant aluminum alloy.

[0011] The performance parameters of the high-performance heat-resistant aluminum alloy meet the following standards: yield strength ≥460MPa, tensile strength ≥520MPa, and elongation after fracture ≥14%.

[0012] Furthermore, the time of heat preservation and melting in step (1) is 1 to 3 hours, and mechanical stirring is applied intermittently during the heat preservation and melting process, that is, stirring is performed once every 30 minutes, and each stirring lasts 10 to 20 minutes; the time of heat preservation and melting in step (3) is 1 to 2 hours, and mechanical stirring is applied intermittently during the heat preservation and melting process, that is, stirring is performed once every 30 minutes, and each stirring lasts 10 to 20 minutes. Intermittent application of mechanical stirring is conducive to promoting uniform melting of the charge.

[0013] Furthermore, the refining gases used in the primary refining and the secondary refining are both mixed gases consisting of high-purity argon gas with a concentration of 99.99% and high-purity chlorine gas with a concentration of 99.99%, wherein the content ratio of the high-purity argon gas to the high-purity chlorine gas is 99:1.

[0014] A method for preparing a seamless pipe comprises the following steps: S1, taking the above melt D, after double-stage filtration treatment, entering the casting mold plate for semi-continuous casting to obtain round rods; S2, taking the round rod obtained in step S1 and putting it into a heating furnace for homogenization treatment at 460-560° C. for 18-48 hours, then taking out the round rod and cooling it to room temperature, then sawing the round rod into the required length, and then putting the cut short round rod into an industrial frequency heating device and heating it to 400-500° C., then taking out the round rod and reversely extruding it into a seamless pipe, and cooling it to room temperature; S3, taking the seamless pipe obtained in step S2 and placing it in a vertical quenching furnace for solution treatment, the temperature of the solution treatment is 480-560°C, the time of the solution treatment is 2-8 hours, after the solution treatment, the seamless pipe is cooled to room temperature, and then the seamless pipe is stretched, straightened and pre-stretched, and after completion, it is placed in a straightening machine for straightening; S4, placing the seamless pipe processed in step S3 into an aging furnace for artificial aging, the artificial aging temperature is 150-205°C, the artificial aging time is 16-48 hours, after the artificial aging is completed, the seamless pipe is removed from the aging furnace and cooled to room temperature by strong wind, and then sent to the finished product warehouse for storage.

[0015] Furthermore, the furnace outlet temperature of the melt D in step S1 is 680-720°C. When the melt D is discharged from the smelting furnace and passes through the flow channel, an aluminum-titanium-boron alloy rod is added to refine the grains. Then, the melt D is subjected to double-stage filtration treatment and then passes through a crystallizer into a casting mold for semi-continuous casting to obtain round rods. The first stage of the double-stage filtration uses a 60-mesh ceramic filter plate, and the second stage uses an 80-mesh ceramic filter plate. The crystallizer descends at a speed of 40-150 mm / min.

[0016] Further, in step S2, after homogenization, the round rod is taken out and cooled to room temperature by spray-enhanced wind cooling, and the cooling rate is 5-50°C / minute; the seamless pipe obtained by reverse extrusion is cooled to room temperature by air cooling, and the cooling rate is 10-30°C / minute, and the extrusion speed is 2-8 meters / minute; in step S3, after the solution treatment, the seamless pipe is cooled to room temperature by water cooling, and the cooling rate is 200-800°C / minute; in step S4, after the artificial aging is completed, the seamless pipe is removed from the aging furnace and cooled to room temperature by strong wind, and the cooling rate is 50-100°C / minute. By adopting different cooling methods according to the characteristics of intermediate products at different stages, not only can the cooling efficiency be improved, but also the influence of improper cooling rate on product performance can be avoided.

[0017] Furthermore, in step S3, the seamless pipe is stretched, straightened and pre-stretched, and then placed in a straightening machine for straightening. The deformation applied by the stretching and straightening is 1 to 3%, and the deformation applied by the pre-stretching is 3 to 6%.

[0018] Compared with the prior art, this technical solution has the following beneficial effects: The present invention uses Cu, Mg and Si as main alloy elements, optimizes the dosage of Fe, Mn, Ni, Mo, Zr, Ag, Ti and other elements, and uses La, Nd, Er and other rare earth elements as reinforcing agents to improve the performance of aluminum alloy, so that the aluminum alloy produced has excellent room temperature mechanical properties, heat resistance and plasticity. The seamless pipe obtained by using the high-performance heat-resistant aluminum alloy of the present invention after a series of forming processes and heat treatment has excellent high temperature resistance, corrosion resistance and fatigue resistance, and can be used as a drill pipe, solving the problem of short service life of the existing aluminum alloy drill pipe under heat exposure or high temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The metallographic phase diagram is 100 times that of the high performance heat-resistant aluminum alloy cast rod prepared in Example 1.

[0020] Figure 2 This is a 500-fold metallographic image of the seamless pipe prepared in Example 1. DETAILED DESCRIPTION

[0021] The present invention is further described by the following examples, but is not intended to be limiting of the present invention. Specific experimental conditions and methods not specified in the following examples are conventional methods commonly known to those skilled in the art.

[0022] Embodiment 1: A high performance heat-resistant aluminum alloy comprising the following chemical components in mass fractions: Cu: 5.2%, Mg: 0.75%, Si: 0.86%, Ni: 0.45%, Mn: 0.82%, Mo: 0.13%, Zr: 0.17%, Ag: 0.09%, Ti: 0.04%, Fe: 0.26%, La: 0.35%, Nd: 0.25%, Er: 0.16%, other unavoidable single impurity elements ≤ 0.03%, the total amount of impurity elements ≤ 0.15%, the balance is aluminum; the content ratio of the three elements La, Nd and Er is 3.5:2.5:1.6; The method for preparing the high-performance heat-resistant aluminum alloy described in this embodiment comprises the following steps: (1) weighing raw materials in proportion, placing aluminum ingots, electrolytic copper, aluminum-nickel master alloy, aluminum-manganese master alloy, aluminum-molybdenum master alloy, aluminum-zirconium master alloy, aluminum-silver master alloy, aluminum-iron master alloy, aluminum-lanthanum master alloy, aluminum-neodymium master alloy, and aluminum-erbium master alloy in a smelting furnace and heating them until they are melted, and then smelting them at 800° C. to obtain a melt A; the smelting time is 2.5 hours, and mechanical stirring is intermittently applied during the smelting process, that is, stirring is performed every 30 minutes, and each stirring lasts for 10 minutes; (2) taking the melt A obtained in step (1) and refining it once at 780° C. for 60 minutes, and then standing and skimming to obtain melt B; (3) Adding industrial silicon and magnesium ingots to the melt B obtained in step (2) and smelting the melt at 760° C., taking samples from the melt for chemical composition analysis, and if there is a deviation in the composition, taking the raw materials in step (1) for composition adjustment and taking samples for analysis again until all elements reach the expected indicators, thereby obtaining a melt C; the smelting time is 1.8 hours, and mechanical stirring is intermittently applied during the smelting process, that is, stirring once every 30 minutes, and each stirring lasts for 10 minutes; (4) The melt C obtained in step (3) is subjected to secondary refining at 740° C. for 20 minutes, and then allowed to stand for slagging. A sample is taken from the melt for chemical composition analysis. If the composition is deviated, the raw material in step (1) is adjusted for composition, and then secondary refining is performed again and sampling is performed again for analysis until all elements reach the expected indexes to obtain a melt D. The melt D is cast to obtain a high-performance heat-resistant aluminum alloy. The refining gas used in the primary refining and the secondary refining is a mixed gas composed of high-purity argon gas with a concentration of 99.99% and high-purity chlorine gas with a concentration of 99.99%, wherein the content ratio of the high-purity argon gas to the high-purity chlorine gas is 99:1.

[0023] The method for preparing the seamless pipe described in this embodiment comprises the following steps: S1, taking the melt D and subjecting it to double-stage filtration treatment, and then entering the casting mold plate for semi-continuous casting to obtain a round rod; the furnace temperature of the melt D is 680°C, and when the melt D is discharged from the smelting furnace and passes through the flow channel, an aluminum-titanium-boron alloy rod is added for grain refinement treatment, and then the melt D is subjected to double-stage filtration treatment and then passes through a crystallizer into a casting mold plate for semi-continuous casting to obtain a Φ220 mm round rod, the first stage of the double-stage filtration uses a 60-mesh ceramic filter plate, the second stage uses an 80-mesh ceramic filter plate, and the crystallizer descends at a speed of 86 mm / min; S2, take the round rod obtained in step S1 and put it into a heating furnace for homogenization treatment at 520°C for 24 hours, then take out the round rod and cool it to room temperature by spraying and strengthening wind cooling, the cooling rate is 15°C / min, then cut the round rod into the required length, and then put the cut short round rod into the power frequency heating equipment and heat it to 475°C, then take out the round rod and reverse extrude it to form a seamless pipe with a diameter of Φ90 and a thickness of 9mm, the extrusion speed is 4 meters / min, and the seamless pipe obtained by reverse extrusion is cooled to room temperature by air cooling, and the cooling rate is 25°C / min; S3, taking the seamless pipe obtained in step S2 and putting it into a vertical quenching furnace for solution treatment, the temperature of the solution treatment is 520°C, the time of the solution treatment is 3 hours, after the solution treatment, the seamless pipe is cooled to room temperature by water cooling, the cooling rate is 650°C / min, the seamless pipe is stretched, straightened and pre-stretched, and after completion, it is put into a straightening machine for straightening, the deformation applied by stretching and straightening is 2%, and the deformation applied by pre-stretching is 4%; S4. The seamless pipe treated in step S3 is placed in an aging furnace for artificial aging. The temperature of artificial aging is 165°C and the time of artificial aging is 18 hours. After the artificial aging is completed, the seamless pipe is removed from the aging furnace and cooled to room temperature by strong wind. The cooling rate is 60°C / minute, and then sent to the finished product warehouse for storage.

[0024] Embodiment 2: A high performance heat-resistant aluminum alloy comprising the following chemical components in mass fractions: Cu: 6.1%, Mg: 0.18%, Si: 1.1%, Ni: 0.52%, Mn: 0.53%, Mo: 0.16%, Zr: 0.14%, Ag: 0.08%, Ti: 0.02%, Fe: 0.28%, La: 0.28%, Nd: 0.17%, Er: 0.29%, other unavoidable single impurity elements ≤ 0.03%, the total amount of impurity elements ≤ 0.15%, the balance is aluminum; the content ratio of the three elements La, Nd and Er is 2.8:1.7:2.9; The method for preparing the high-performance heat-resistant aluminum alloy described in this embodiment comprises the following steps: (1) weighing raw materials in proportion, placing aluminum ingots, electrolytic copper, aluminum-nickel master alloy, aluminum-manganese master alloy, aluminum-molybdenum master alloy, aluminum-zirconium master alloy, aluminum-silver master alloy, aluminum-iron master alloy, aluminum-lanthanum master alloy, aluminum-neodymium master alloy, and aluminum-erbium master alloy in a smelting furnace and heating them until they are melted, and then smelting them at 820° C. to obtain a melt A; the smelting time is 3 hours, and mechanical stirring is intermittently applied during the smelting process, that is, stirring is performed every 30 minutes, and each stirring lasts for 10 minutes; (2) taking the melt A obtained in step (1) and refining it once at 760° C. for 65 minutes, and then standing and skimming to obtain melt B; (3) Adding industrial silicon and magnesium ingots to the melt B obtained in step (2) and smelting at 780°C, taking samples from the melt for chemical composition analysis. If the composition is deviated, taking the raw materials in step (1) for composition adjustment and taking samples for analysis again until all elements reach the expected indicators, thereby obtaining a melt C; the smelting time is 2 hours, and mechanical stirring is intermittently applied during the smelting process, that is, stirring once every 30 minutes, and each stirring lasts for 10 minutes; (4) The melt C obtained in step (3) is subjected to secondary refining at 730° C. for 30 minutes, and then allowed to stand for slag removal. Samples are taken from the melt for chemical composition analysis. If the composition is deviated, the raw material in step (1) is adjusted for composition, and then secondary refining is performed again and samples are taken for analysis again until all elements reach the expected indexes to obtain a melt D. The melt D is cast to obtain a high-performance heat-resistant aluminum alloy. The refining gas used in the primary refining and the secondary refining is a mixed gas composed of high-purity argon gas with a concentration of 99.99% and high-purity chlorine gas with a concentration of 99.99%, wherein the content ratio of the high-purity argon gas to the high-purity chlorine gas is 99:1.

[0025] The method for preparing the seamless pipe described in this embodiment comprises the following steps: S1, taking the melt D and subjecting it to double-stage filtration treatment, and then entering the casting mold for semi-continuous casting to obtain round rods; the furnace temperature of the melt D is 720°C, and when the melt D is discharged from the smelting furnace and passes through the flow channel, an aluminum-titanium-boron alloy rod is added for grain refinement treatment, and then the melt D is subjected to double-stage filtration treatment and then passes through a crystallizer into a casting mold for semi-continuous casting to obtain a Φ254mm round rod, the first stage of the double-stage filtration uses a 60-mesh ceramic filter plate, the second stage uses an 80-mesh ceramic filter plate, and the crystallizer descends at a speed of 70 mm / min; S2, take the round rod obtained in step S1 and put it into a heating furnace for homogenization treatment at 500°C for 30 hours, then take out the round rod and cool it to room temperature by spraying and strengthening wind cooling, the cooling rate is 10°C / min, then cut the round rod into the required length, and then put the cut short round rod into the power frequency heating equipment and heat it to 455°C, then take out the round rod and reverse extrude it to make a seamless pipe with a diameter of Φ100 and a thickness of 12 mm, the extrusion speed is 6 meters / min, and the seamless pipe obtained by reverse extrusion is cooled to room temperature by air cooling, and the cooling rate is 25°C / min; S3, taking the seamless pipe obtained in step S2 and putting it into a vertical quenching furnace for solution treatment, the temperature of the solution treatment is 500°C, the time of the solution treatment is 3.5 hours, after the solution treatment, the seamless pipe is cooled to room temperature by water cooling, the cooling rate is 700°C / min, the seamless pipe is stretched, straightened and pre-stretched, and after completion, it is put into a straightening machine for straightening, the deformation applied by stretching and straightening is 1-3%, and the deformation applied by pre-stretching is 3-6%; S4. The seamless pipe treated in step S3 is placed in an aging furnace for artificial aging. The temperature of artificial aging is 160°C and the time of artificial aging is 26 hours. After the artificial aging is completed, the seamless pipe is removed from the aging furnace and cooled to room temperature by strong wind. The cooling rate is 70°C / minute, and then sent to the finished product warehouse for storage.

[0026] Embodiment 3: A high performance heat-resistant aluminum alloy comprising the following chemical components in mass fractions: Cu: 4.9%, Mg: 0.92%, Si: 0.87%, Ni: 0.58%, Mn: 1.27%, Mo: 0.16%, Zr: 0.13%, Ag: 0.10%, Ti: 0.02%, Fe: 0.21%, La: 0.24%, Nd: 0.18%, Er: 0.12%, other unavoidable single impurity elements ≤ 0.03%, the total amount of impurity elements ≤ 0.15%, the balance is aluminum; the content ratio of the three elements La, Nd and Er is 2.1:1.8:1.2; The method for preparing the high-performance heat-resistant aluminum alloy described in this embodiment comprises the following steps: (1) weighing raw materials in proportion, placing aluminum ingots, electrolytic copper, aluminum-nickel master alloy, aluminum-manganese master alloy, aluminum-molybdenum master alloy, aluminum-zirconium master alloy, aluminum-silver master alloy, aluminum-iron master alloy, aluminum-lanthanum master alloy, aluminum-neodymium master alloy, and aluminum-erbium master alloy in a melting furnace and heating them to melt, and then melting them at 780° C. to obtain a melt A; the melting time is 2.5 hours, and mechanical stirring is intermittently applied during the melting process, that is, stirring is performed every 30 minutes, and each stirring lasts for 15 minutes; (2) taking the melt A obtained in step (1) and refining it once at 770° C. for 70 minutes, and then standing and skimming to obtain melt B; (3) Adding industrial silicon and magnesium ingots to the melt B obtained in step (2) and smelting the melt at 780°C, taking samples from the melt for chemical composition analysis. If the composition is deviated, adjusting the composition of the raw materials in step (1) and taking samples for analysis again until all elements reach the expected indexes, thereby obtaining a melt C; the smelting time is 1 hour, and mechanical stirring is intermittently applied during the smelting process, i.e. stirring once every 30 minutes, and each stirring lasts for 15 minutes; (4) The melt C obtained in step (3) is subjected to secondary refining at 730° C. for 30 minutes, and then allowed to stand for slag removal. Samples are taken from the melt for chemical composition analysis. If the composition is deviated, the raw material in step (1) is adjusted for composition, and then secondary refining is performed again and samples are taken for analysis again until all elements reach the expected indexes to obtain a melt D. The melt D is cast to obtain a high-performance heat-resistant aluminum alloy. The refining gas used in the primary refining and the secondary refining is a mixed gas composed of high-purity argon gas with a concentration of 99.99% and high-purity chlorine gas with a concentration of 99.99%, wherein the content ratio of the high-purity argon gas to the high-purity chlorine gas is 99:1.

[0027] The method for preparing the seamless pipe described in this embodiment comprises the following steps: S1, taking the melt D and subjecting it to double-stage filtration treatment, and then entering the casting mold plate for semi-continuous casting to obtain round rods; the furnace temperature of the melt D is 715°C, and when the melt D is discharged from the smelting furnace and passes through the flow channel, an aluminum-titanium-boron alloy rod is added for grain refinement treatment, and then the melt D is subjected to double-stage filtration treatment and then passes through a crystallizer into a casting mold plate for semi-continuous casting to obtain a Φ178mm round rod, the first stage of the double-stage filtration uses a 60-mesh ceramic filter plate, the second stage uses an 80-mesh ceramic filter plate, and the crystallizer descends at a speed of 82 mm / min; S2, take the round rod obtained in step S1 and put it into a heating furnace for homogenization treatment at 540°C for 18 hours, then take out the round rod and cool it to room temperature by spraying and strengthening wind cooling, the cooling rate is 11°C / min, then cut the round rod into required lengths, and then put the cut short round rods into a power frequency heating device and heat them to 460°C, then take out the round rod and reverse extrude it to form a seamless pipe with a diameter of Φ70 and a thickness of 9 mm, the extrusion speed is 3 meters / min, and the seamless pipe obtained by reverse extrusion is cooled to room temperature by air cooling, and the cooling rate is 30°C / min; S3, taking the seamless pipe obtained in step S2 and putting it into a vertical quenching furnace for solution treatment, the temperature of the solution treatment is 540°C, the time of the solution treatment is 3 hours, after the solution treatment, the seamless pipe is cooled to room temperature by water cooling, the cooling rate is 660°C / min, the seamless pipe is stretched, straightened and pre-stretched, and after completion, it is put into a straightening machine for straightening, the deformation applied by stretching and straightening is 2%, and the deformation applied by pre-stretching is 4%; S4. The seamless pipe treated in step S3 is placed in an aging furnace for artificial aging. The temperature of artificial aging is 165°C and the time of artificial aging is 18 hours. After the artificial aging is completed, the seamless pipe is removed from the aging furnace and cooled to room temperature by strong wind. The cooling rate is 80°C / minute, and then sent to the finished product warehouse for storage.

[0028] Embodiment 4: A high performance heat-resistant aluminum alloy comprising the following chemical components in mass fractions: Cu: 4.5%, Mg: 0.5%, Si: 0.5%, Ni: 0.2%, Mn: 0.3%, Mo: 0.03%, Zr: 0.03%, Ag: 0.03%, Ti: 0.01%, Fe: 0.35%, La: 0.05%, Nd: 0.05%, Er: 0.05%, other unavoidable single impurity elements ≤ 0.03%, the total amount of impurity elements ≤ 0.15%, the balance is aluminum; the content ratio of the three elements La, Nd and Er is 1:1:1; The method for preparing the high-performance heat-resistant aluminum alloy described in this embodiment comprises the following steps: (1) weighing raw materials in proportion, placing aluminum ingots, electrolytic copper, aluminum-nickel master alloy, aluminum-manganese master alloy, aluminum-molybdenum master alloy, aluminum-zirconium master alloy, aluminum-silver master alloy, aluminum-iron master alloy, aluminum-lanthanum master alloy, aluminum-neodymium master alloy, and aluminum-erbium master alloy in a smelting furnace and heating them to melt, and then smelting them at 760° C. to obtain a melt A; the smelting time is 2.5 hours, and mechanical stirring is intermittently applied during the smelting process, that is, stirring is performed every 30 minutes, and each stirring lasts for 10 minutes; (2) taking the melt A obtained in step (1) and refining it once at 760° C. for 40 minutes, and then letting it stand and skimming off the slag to obtain melt B; (3) Adding industrial silicon and magnesium ingots to the melt B obtained in step (2) and melting them at 745°C, taking samples from the melt for chemical composition analysis. If the composition is deviated, taking the raw materials in step (1) for composition adjustment and taking samples for analysis again until all elements reach the expected indicators, thereby obtaining a melt C; the melting time is 2 hours, and mechanical stirring is intermittently applied during the melting process, that is, stirring once every 30 minutes, and each stirring lasts for 10 minutes; (4) The melt C obtained in step (3) is subjected to secondary refining at 735° C. for 20 minutes, and then allowed to stand for slag removal to obtain melt D. Samples are taken from the melt for chemical composition analysis. If the composition is deviated, the raw material in step (1) is taken for composition adjustment, and then secondary refining is performed again and samples are taken for analysis again until all elements reach the expected indexes to obtain melt D; The refining gas used in the primary refining and the secondary refining is a mixed gas composed of high-purity argon gas with a concentration of 99.99% and high-purity chlorine gas with a concentration of 99.99%, wherein the content ratio of the high-purity argon gas to the high-purity chlorine gas is 99:1.

[0029] The method for preparing the seamless pipe described in this embodiment comprises the following steps: S1, taking the melt D and subjecting it to double-stage filtration treatment, and then entering the casting mold plate for semi-continuous casting to obtain round rods; the furnace temperature of the melt D is 680°C, and when the melt D is discharged from the smelting furnace and passes through the flow channel, an aluminum-titanium-boron alloy rod is added for grain refinement treatment, and then the melt D is subjected to double-stage filtration treatment and then passes through a crystallizer into a casting mold plate for semi-continuous casting to obtain round rods, the first stage of the double-stage filtration uses a 60-mesh ceramic filter plate, the second stage uses an 80-mesh ceramic filter plate, and the crystallizer descends at a speed of 40 mm / min; S2, taking the round rod obtained in step S1 and putting it into a heating furnace for homogenization treatment at 460°C for 18 hours, then taking out the round rod and cooling it to room temperature by spraying and strengthening wind cooling, the cooling rate is 9°C / min, then sawing the round rod into the required length, and then putting the cut short round rod into the power frequency heating equipment and heating it to 400°C, then taking out the round rod and reversely extruding it to form a seamless pipe with a diameter of Φ70 and a thickness of 9mm, the extrusion speed is 2 meters / min, and the seamless pipe obtained by reverse extrusion is cooled to room temperature by air cooling, and the cooling rate is 25°C / min; S3, taking the seamless pipe obtained in step S2 and putting it into a vertical quenching furnace for solution treatment, the temperature of the solution treatment is 480°C, the time of the solution treatment is 8 hours, after the solution treatment, the seamless pipe is cooled to room temperature by water cooling, the cooling rate is 500°C / min, the seamless pipe is stretched, straightened and pre-stretched, and after completion, it is put into a straightening machine for straightening, the deformation applied by stretching and straightening is 1%, and the deformation applied by pre-stretching is 3%; S4. The seamless pipe treated in step S3 is placed in an aging furnace for artificial aging. The temperature of artificial aging is 150°C and the time of artificial aging is 36 hours. After the artificial aging is completed, the seamless pipe is removed from the aging furnace and cooled to room temperature by strong wind. The cooling rate is 90°C / minute, and then sent to the finished product warehouse for storage.

[0030] Embodiment 5: A high performance heat-resistant aluminum alloy comprising the following chemical components in mass fractions: Cu: 6.5%, Mg: 2.3%, Si: 1.5%, Ni: 0.8%, Mn: 2.0%, Mo: 0.2%, Zr: 0.2%, Ag: 0.2%, Ti: 0.15%, Fe: 0.4%, La: 0.5%, Nd: 0.5%, Er: 0.5%, other unavoidable single impurity elements ≤ 0.03%, the total amount of impurity elements ≤ 0.15%, the balance is aluminum; the content ratio of the three elements La, Nd and Er is 1:1:1; The method for preparing the high-performance heat-resistant aluminum alloy described in this embodiment comprises the following steps: (1) weighing raw materials in proportion, placing aluminum ingots, electrolytic copper, aluminum-nickel master alloy, aluminum-manganese master alloy, aluminum-molybdenum master alloy, aluminum-zirconium master alloy, aluminum-silver master alloy, aluminum-iron master alloy, aluminum-lanthanum master alloy, aluminum-neodymium master alloy, and aluminum-erbium master alloy in a smelting furnace and heating them to melt, and then smelting them at 860° C. to obtain a melt A; the smelting time is 2.5 hours, and mechanical stirring is intermittently applied during the smelting process, that is, stirring is performed every 30 minutes, and each stirring lasts for 15 minutes; (2) taking the melt A obtained in step (1) and refining it once at 765° C. for 70 minutes, and then letting it stand and skimming off the slag to obtain melt B; (3) Adding industrial silicon and magnesium ingots to the melt B obtained in step (2) and smelting the melt at 820° C., taking samples from the melt for chemical composition analysis, and if there is a deviation in the composition, taking the raw materials in step (1) for composition adjustment and taking samples for analysis again until all elements reach the expected indicators, thereby obtaining a melt C; the smelting time is 1.8 hours, and mechanical stirring is intermittently applied during the smelting process, that is, stirring once every 30 minutes, and each stirring lasts for 15 minutes; (4) The melt C obtained in step (3) is subjected to secondary refining at 740° C. for 40 minutes, and then allowed to stand for slag removal. Samples are taken from the melt for chemical composition analysis. If the composition is deviated, the raw material in step (1) is adjusted for composition, and then secondary refining is performed again and samples are taken for analysis again until all elements reach the expected indexes to obtain a melt D. The melt D is cast to obtain a high-performance heat-resistant aluminum alloy. The refining gas used in the primary refining and the secondary refining is a mixed gas composed of high-purity argon gas with a concentration of 99.99% and high-purity chlorine gas with a concentration of 99.99%, wherein the content ratio of the high-purity argon gas to the high-purity chlorine gas is 99:1.

[0031] The method for preparing the seamless pipe described in this embodiment comprises the following steps: S1, taking the melt D and subjecting it to double-stage filtration treatment, and then entering the casting mold for semi-continuous casting to obtain round rods; the outlet temperature of the melt D is 720°C, and when the melt D is discharged from the smelting furnace and passes through the launder, an aluminum-titanium-boron alloy rod is added for grain refinement treatment, and then the melt D is subjected to double-stage filtration treatment and then passes through a crystallizer into a casting mold for semi-continuous casting to obtain round rods, the first stage of the double-stage filtration uses a 60-mesh ceramic filter plate, the second stage uses an 80-mesh ceramic filter plate, and the crystallizer descends at a speed of 150 mm / min; S2, take the round rod obtained in step S1 and put it into a heating furnace for homogenization treatment at 560°C for 18 hours, then take out the round rod and cool it to room temperature by spraying and strengthening wind cooling, the cooling rate is 18°C / min, then cut the round rod into required lengths, and then put the cut short round rods into a power frequency heating device and heat them to 480°C, then take out the round rod and reverse extrude it to form a seamless pipe with a diameter of Φ100 and a thickness of 12 mm, the extrusion speed is 8 m / min, and the seamless pipe obtained by reverse extrusion is cooled to room temperature by air cooling, and the cooling rate is 25°C / min; S3, taking the seamless pipe obtained in step S2 and putting it into a vertical quenching furnace for solution treatment, the temperature of the solution treatment is 560°C, the time of the solution treatment is 2 hours, after the solution treatment, the seamless pipe is cooled to room temperature by water cooling, the cooling rate is 450°C / min, the seamless pipe is stretched, straightened and pre-stretched, and after completion, it is put into a straightening machine for straightening, the deformation applied by stretching and straightening is 3%, and the deformation applied by pre-stretching is 6%; S4. The seamless pipe treated in step S3 is placed in an aging furnace for artificial aging. The temperature of artificial aging is 205°C and the time of artificial aging is 16 hours. After the artificial aging is completed, the seamless pipe is removed from the aging furnace and cooled to room temperature by strong wind. The cooling rate is 70°C / minute, and then sent to the finished product warehouse for storage.

[0032] Comparative Example 1: A seamless pipe is produced using conventional 2014-T6 aluminum alloy material, that is, 2014-T6 aluminum alloy is smelted to obtain an alloy melt, and then the alloy melt is cast, homogenized, reverse extruded, stretched and straightened, pre-stretched, straightened, solution treated, and artificially aged according to the preparation method of the seamless pipe in Example 1 to obtain a seamless pipe product.

[0033] Comparative Example 2: A seamless pipe is produced using conventional 2024-T4 aluminum alloy material, that is, 2024-T4 aluminum alloy is used to obtain an alloy melt after smelting, and then the alloy melt is cast, homogenized, reverse extruded, stretched and straightened, pre-stretched, straightened, solution treated, and artificially aged according to the preparation method of the seamless pipe in Example 1 to obtain a seamless pipe product.

[0034] Experimental Example 1: A seamless pipe was prepared according to the methods described in Examples 1 to 5 and Comparative Examples 1 to 2, and the following tests were performed: Room temperature mechanical properties test: According to GB / T 228.1-2010 “Tensile tests on metallic materials Part 1: Room temperature test methods”, samples were randomly taken from seamless pipes and machined into tensile specimens, which were then tested on a tensile testing machine. The results are shown in Table 1.

[0035] Table 1 Mechanical properties test results of seamless pipes

[0036] Heat resistance test: The seamless pipe was kept at 175℃ and 200℃ for 500 hours respectively. After cooling to room temperature, samples were taken for tensile test according to GB / T 228.1-2010 "Tensile test of metallic materials Part 1: Room temperature test method". The results are shown in Table 2.

[0037] Table 2 Performance test results of seamless pipes after heat exposure

[0038] It can be seen from Table 1 that the yield strength, tensile strength and elongation of the seamless pipe prepared by the present invention are higher than those of 2014-T6 and 2024-T4 aluminum alloys; it can be seen from Table 2 that the mechanical properties of the seamless pipe prepared by the present invention at room temperature are higher than those of 2014-T6 and 2024-T4 aluminum alloys after 500 hours of heat exposure at 200°C and 175°C.

[0039] Experimental Example 2: A high-performance heat-resistant aluminum alloy was prepared according to the method described in Examples 1 to 5 and the aluminum alloy materials described in Comparative Examples 1 to 2 were taken for comparison. Their performances were tested. The specific results are shown in Table 3.

[0040] Table 3 Test results of high performance heat-resistant aluminum alloys prepared by different methods

[0041] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A high performance heat-resistant aluminum alloy, characterized in that: The chemical components include the following mass fractions: Cu: 4.5-6.5%, Mg: 0.5-2.3%, Si: 0.5-1.5%, Ni: 0.2-0.8%, Mn: 0.3-2.0%, Mo: 0.03-0.2%, Zr: 0.03-0.2%, Ag: 0.03-0.2%, Ti: 0.01-0.15%, Fe≤0.4%, La: 0.05-0.5%, Nd: 0.05-0.5%, Er: 0.05-0.5%, other unavoidable single impurity elements ≤0.03%, the total amount of impurity elements ≤0.15%, the balance is aluminum.

2. The high performance heat-resistant aluminum alloy according to claim 1, characterized in that: The high performance heat-resistant aluminum alloy comprises the following chemical components in mass fraction: Cu: 4.6-6.3%, Mg: 0.6-2.0%, Si: 0.6-1.3%, Ni: 0.4-0.6%, Mn: 0.6-1.6%, Mo: 0.05-0.18%, Zr: 0.05-0.18%, Ag: 0.05-0.18%, Ti: 0.01-0.12%, Fe≤0.3%, La: 0.1-0.4%, Nd: 0.1-0.4%, Er: 0.1-0.4%, other unavoidable single impurity elements ≤0.03%, the total amount of impurity elements ≤0.15%, the balance is aluminum.

3. The high performance heat-resistant aluminum alloy according to claim 1, characterized in that: The total content of the three elements La, Nd and Er is not less than 0.25% and not more than 0.80%, and the content ratio of the three elements La, Nd and Er is (2-5):(1-4):(1-4).

4. The method for preparing a high performance heat-resistant aluminum alloy according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) weighing raw materials in proportion, placing aluminum ingot, electrolytic copper, aluminum-nickel master alloy, aluminum-manganese master alloy, aluminum-molybdenum master alloy, aluminum-zirconium master alloy, aluminum-silver master alloy, aluminum-iron master alloy, aluminum-lanthanum master alloy, aluminum-neodymium master alloy, and aluminum-erbium master alloy in a melting furnace and heating them until they are melted, and then melting them at 760-860° C. to obtain a melt A; (2) taking the melt A obtained in step (1) and refining it once at 740-780° C. for 40-70 minutes, and then letting it stand and skimming off the slag to obtain melt B; (3) Adding industrial silicon and magnesium ingots to the melt B obtained in step (2) and smelting the melt at 720-820° C., taking samples from the melt for chemical composition analysis. If the composition is deviated, taking the raw materials in step (1) for composition adjustment and taking samples for analysis again until all elements reach the expected indexes, thereby obtaining melt C; (4) The melt C obtained in step (3) is subjected to secondary refining at 700-760° C. for 20-40 minutes, and then allowed to stand for slag removal. Samples are taken from the melt for chemical composition analysis. If the composition deviates, the raw material in step (1) is adjusted for composition, and then secondary refining is performed again and samples are taken for analysis again until all elements reach the expected indexes to obtain a melt D. The melt D is cast to obtain a high-performance heat-resistant aluminum alloy.

5. The method for preparing a high performance heat-resistant aluminum alloy according to claim 4, characterized in that: The time for heat preservation and melting in step (1) is 1 to 3 hours, and mechanical stirring is applied intermittently during the heat preservation and melting process, that is, stirring is performed once every 30 minutes, and each stirring lasts 10 to 20 minutes; the time for heat preservation and melting in step (3) is 1 to 2 hours, and mechanical stirring is applied intermittently during the heat preservation and melting process, that is, stirring is performed once every 30 minutes, and each stirring lasts 10 to 20 minutes.

6. The method for preparing a high performance heat-resistant aluminum alloy according to claim 4, characterized in that: The refining gas used in the primary refining and the secondary refining is a mixed gas composed of high-purity argon gas with a concentration of 99.99% and high-purity chlorine gas with a concentration of 99.99%, wherein the content ratio of the high-purity argon gas to the high-purity chlorine gas is 99:

1.

7. A method for preparing a seamless pipe, characterized in that: The following steps are involved: S1, taking the melt D described in claim 4, after double-stage filtration treatment, entering the casting mold plate for semi-continuous casting to obtain round rods; S2, taking the round rod obtained in step S1 and putting it into a heating furnace for homogenization treatment at 460-560° C. for 18-48 hours, then taking out the round rod and cooling it to room temperature, then sawing the round rod into the required length, and then putting the cut short round rod into an industrial frequency heating device and heating it to 400-500° C., then taking out the round rod and reversely extruding it into a seamless pipe, and cooling it to room temperature; S3, taking the seamless pipe obtained in step S2 and placing it in a vertical quenching furnace for solution treatment, the temperature of the solution treatment is 480-560°C, the time of the solution treatment is 2-8 hours, after the solution treatment, the seamless pipe is cooled to room temperature, and then the seamless pipe is stretched, straightened and pre-stretched, and after completion, it is placed in a straightening machine for straightening; S4, placing the seamless pipe processed in step S3 into an aging furnace for artificial aging, the artificial aging temperature is 150-205°C, the artificial aging time is 16-48 hours, after the artificial aging is completed, the seamless pipe is removed from the aging furnace and cooled to room temperature by strong wind, and then sent to the finished product warehouse for storage.

8. The method for preparing a seamless pipe according to claim 7, characterized in that: The furnace outlet temperature of the melt D in step S1 is 680-720°C. When the melt D is discharged from the smelting furnace and passes through the flow channel, an aluminum-titanium-boron alloy rod is added to refine the grains. Then, the melt D is subjected to double-stage filtration treatment and then passes through a crystallizer into a casting mold for semi-continuous casting to obtain round rods. The first stage of the double-stage filtration uses a 60-mesh ceramic filter plate, and the second stage uses an 80-mesh ceramic filter plate. The crystallizer descends at a speed of 40-150 mm / min.

9. The method for preparing a seamless pipe according to claim 7, characterized in that: In step S2, after homogenization, the round rod is taken out and cooled to room temperature by spray-enhanced wind cooling, and the cooling rate is 5-50°C / minute; the seamless pipe obtained by reverse extrusion is cooled to room temperature by air cooling, and the cooling rate is 10-30°C / minute, and the extrusion speed is 2-8 meters / minute; in step S3, after the solution treatment is completed, the seamless pipe is cooled to room temperature by water cooling, and the cooling rate is 200-800°C / minute; in step S4, after artificial aging is completed, the seamless pipe is removed from the aging furnace and cooled to room temperature by strong wind, and the cooling rate is 50-100°C / minute.

10. The method for preparing a seamless pipe according to claim 7, characterized in that: In step S3, the seamless pipe is stretched, straightened and pre-stretched, and then put into a straightening machine for straightening. The deformation applied by stretching and straightening is 1-3%, and the deformation applied by pre-stretching is 3-6%.

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