Round cast ingot for 5XXX aluminum alloy profile and preparation method of round cast ingot

Abstract

The invention provides a round cast ingot for a 5XXX aluminum alloy profile and a preparation method of the round cast ingot. The preparation method comprises the steps of burdening, smelting, solution purification, grain refinement, casting and soaking treatment. In the smelting process, the temperature of a melt is increased to 780-810 DEG C, an Sc source is added, the reaction time is longer than or equal to 40 min, the temperature of the melt is reduced to 730-750 DEG C, then an Mg source and a Zr source are added, and the rest is added along with a furnace; grain refinement is carried out by adopting an AlTi5B1 wire, and the dosage is 1.2 to 1.6 kg / t; the temperature rise speed of soaking treatment is 50-100 DEG C / h, the temperature rise time is 3-6 h, the heat preservation temperature is 300-350 DEG C, and the heat preservation time is 10-15 h. By optimizing the grain refinement process and adopting the low-temperature soaking treatment mode, the obtained product cast ingot is small in segregation, compounds are dispersed and distributed, the structure is uniform and fine, and the metallurgical quality of the 5XXX aluminum alloy round cast ingot is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy preparation, and in particular relates to a round ingot for 5XXX aluminum alloy profiles and a preparation method thereof. Background Art

[0002] 5XXX alloys have medium strength, good corrosion resistance and weldability, but the poor combination of strength and plasticity also limits its development. With the development of aerospace, aviation and shipbuilding technology, higher requirements are placed on the strength of 5XXX alloys. Currently, the commonly used 5XXX alloy extruded profiles have a maximum yield strength requirement of more than 160MPA and an elongation of more than 13% in the mechanical performance standards. With the development of the material field, users have put forward higher requirements for the yield strength and elongation of 5XXX extruded profiles, requiring a yield strength of more than 280MPA and an elongation of more than 12%. The comprehensive performance of existing 5XXX profiles cannot meet user requirements. Summary of the invention

[0003] The object of the present invention is to provide a round ingot for 5XXX aluminum alloy profile and a preparation method thereof. The aluminum alloy profile prepared by the preparation method of the present invention has a yield strength greater than 280MPA and an elongation greater than 12%, meeting the needs of users in different fields.

[0004] The present invention provides a method for preparing a round ingot for a 5XXX aluminum alloy profile, comprising batching, smelting, solution purification, grain refinement, casting, and soaking treatment;

[0005] The ingredients are prepared according to the following chemical composition ratio of the round ingot:

[0006] Si≤0.10%, Fe≤0.12%, Cu≤0.10%, Mg4.0~5.0%, Mn0.2~0.7%, Zn0.05~0.15%, Cr0.05~0.15%, Zr0.05~0.15%, Ti0.05~0.15%, Sc0.15~0.25%, the balance is Al;

[0007] During the smelting process, the melt temperature rises to 780-810°C, the Sc source is added, the reaction time is ≥40min, the melt temperature drops to 730-750°C, and then the Mg source and Zr source are added, and the rest are added with the furnace;

[0008] The melt purification includes furnace refining, online degassing and plate filtration;

[0009] The grain refinement adopts AlTi5B1 wire for grain refinement, and the amount used is 1.2-1.6kg / t;

[0010] The heating rate of the heat treatment is 50-100°C / h, the heating time is 3-6h, the insulation temperature is 300-350°C, and the insulation time is 10-15h.

[0011] Preferably, in the ingredients, the Mg source is metallic Mg, the Zn source is metallic Zn, the Mn source, Cr source, Zr source, Ti source and Sc source are intermediate alloys containing Mn, Cr, Zr, Ti and Sc respectively, and the Al source is an original aluminum ingot with an Al content of 99.95% or above.

[0012] Preferably, the Mn source is AlMn15, the Cr source is AlCr4, the Zr source is ALZr4, the Ti source is AlTi4, and the Sc source is AlSc2.

[0013] Preferably, the furnace refining first adopts powder spray refining, and then adopts argon gas or argon-chlorine mixed gas refining.

[0014] Preferably, in the furnace refining, the time of powder spray refining is 15 to 20 minutes; and the flow rate of the argon gas or argon-chlorine mixed gas is 3 to 5 L / min.

[0015] Preferably, the online degassing adopts argon or argon + chlorine mixed gas refining to reduce the hydrogen content of the melt to less than 0.15ml / 100gAl.

[0016] Preferably, the online degassing adopts double-rotor rotary degassing, and the gas flow rate of the online degassing is 3-4m 3 / h.

[0017] Preferably, the plate-type filtration adopts a two-stage filtration ceramic filter plate, the filtration accuracy of the first-stage ceramic filter plate is not less than 40PPI, and the filtration accuracy of the second-stage ceramic filter plate is not less than 50PPI.

[0018] Preferably, the casting speed is 90-95 mm / min, and the water flow rate is 140-160 m / min. 3 / h, the aluminum liquid temperature at the end of the flow plate is 695~715℃, and the water temperature is 18~30℃.

[0019] The present invention provides a round ingot for 5XXX aluminum alloy profiles, which is prepared according to the preparation method described above.

[0020] The invention provides a method for preparing a round ingot for a 5XXX aluminum alloy profile, comprising batching, smelting, solution purification, grain refinement, casting, and soaking treatment; the batching is performed according to the following chemical composition ratio of the round ingot: Si≤0.10%, Fe≤0.12%, Cu≤0.10%, Mg4.0-5.0%, Mn0.2-0.7%, Zn0.05-0.15%, Cr0.05-0.15%, Zr0.05-0.15%, Ti0.05-0.15%, Sc0.15-0.25%, and the balance is Al ; During the smelting process, the melt temperature rises to 780-810°C, Sc source is added, the reaction time is ≥40min, the melt temperature drops to 730-750°C, Mg source and Zr source are added, and the rest are added with the furnace; the melt purification includes furnace refining, online degassing and plate filtration; the grain refinement adopts AlTi5B1 wire for grain refinement, and the dosage is 1.2-1.6kg / t; the heating rate of the heat treatment is 50-100°C / h, the heating time is 3-6h, the insulation temperature is 300-350°C, and the insulation time is 10-15h. The present invention adjusts the chemical composition of the alloy by adding Sc and Zr elements. First, the fine grain strengthening produced by the primary Al3 (Sc, Zr) particles; second, the dispersion strengthening produced by the precipitation of secondary Al3 (Sc, Zr) particles during the homogenization process; third, the substructure strengthening caused by the Al3 (Sc, Zr) particles inhibiting the recrystallization during the subsequent processing heat treatment, etc., can significantly improve the strength of the alloy. The present invention optimizes the grain refinement process to ensure that the original grains of the ingot are small; adopts a low-temperature heat treatment method, the obtained product ingot has small segregation, the compound is dispersed, and the organization is uniform and fine, thereby improving the metallurgical quality of the 5XXX aluminum alloy round ingot and achieving the goal of improving the comprehensive performance of the profile. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0022] Figure 1 This is a metallographic diagram of the ingot structure in Example 1 of the present invention;

[0023] Figure 2 This is a metallographic diagram of the ingot structure in Example 1 of the present invention (enlarged view);

[0024] Figure 3 This is a metallographic diagram of the ingot structure in Comparative Example 2 of the present invention;

[0025] Figure 4It is the metallographic diagram 9 (enlarged view) of the ingot structure in Comparative Example 2 of the present invention;

[0026] Figure 5 This is a metallographic diagram of the ingot structure in Comparative Example 3 of the present invention;

[0027] Figure 6 It is the metallographic diagram 9 (enlarged view) of the ingot structure in Comparative Example 3 of the present invention;

[0028] Figure 7 This is a metallographic diagram of the ingot structure in Example 3 of the present invention;

[0029] Figure 8 This is a metallographic diagram of the ingot structure in Example 3 of the present invention (enlarged view). DETAILED DESCRIPTION

[0030] The present invention provides a method for preparing a round ingot for a 5XXX aluminum alloy profile, comprising batching, smelting, solution purification, grain refinement, casting, and soaking treatment;

[0031] The ingredients are prepared according to the following chemical composition ratio of the round ingot:

[0032] Si0.06%, Fe0.06%, Cu0.02%, Mg4.38%, Mn0.61%, Zn0.10%, Cr0.10%, Zr0.08%, Ti0.10%, Sc0.22%, the balance is Al;

[0033] During the smelting process, the melt temperature rises to 780-810°C, the Sc source is added, the reaction time is ≥40min, the melt temperature drops to 730-750°C, and then the Mg source and Zr source are added, and the rest are added with the furnace;

[0034] The melt purification includes furnace refining, online degassing and plate filtration;

[0035] The grain refinement adopts AlTi5B1 wire for grain refinement, and the amount used is 1.2-1.6kg / t;

[0036] The heating rate of the heat treatment is 50-100°C / h, the heating time is 3-6h, the insulation temperature is 300-350°C, and the insulation time is 10-15h.

[0037] The present invention preferably prepares ingredients according to the following element contents:

[0038] Si≤0.10%, Fe≤0.12%, Cu≤0.10%, Mg4.0~5.0%, Mn0.2~0.7%, Zn0.05~0.15%, Cr0.05~0.15%, Zr0.05~0.15%, Ti0.05~0.15%, Sc0.15~0.25%, the balance is Al;

[0039] Preferably, 0<Si≤0.08%, 0<Fe≤0.1%, 0<Cu≤0.05%, Mg4.2~4.8%, Mn0.4~0.7%, Zn0.05~0.12%, Cr0.08~0.12%, Zr0.08~0.12%, Ti0.06~0.12%, Sc0.18~0.24%, and the balance is Al;

[0040] More preferably, 0<Si≤0.06%, 0<Fe≤0.12%, 0<Cu≤0.02%, Mg4.4~4.6%, Mn0.6~0.7%, Zn0.05~0.09%, Cr0.09~0.10%, Zr0.09~0.10%, Ti0.07~0.10%, Sc0.2~0.24%, and the balance is Al.

[0041] The present invention preferably uses original aluminum ingots, intermediate alloys, and pure metal ingredients with an Al content of 99.95% or above. Mg and Zn elements are pure metal ingredients, and Mn, Cr, Zr, Ti, and Sc are intermediate alloy ingredients. In the present invention, the Mg source is metal Mg, the Zn source is metal Zn, and the Mn source, Cr source, Zr source, Ti source, and Sc source are intermediate alloys containing Mn, Cr, Zr, Ti, and Sc, respectively. Specifically, the Mn source is AlMn15, the Cr source is AlCr4 intermediate alloy, the Zr source is AlZr4 intermediate alloy, the Ti source is AlTi4 intermediate alloy, and the Sc source is AlSc2 intermediate alloy; the Si, Fe, and Cu are impurity elements brought into the above intermediate alloy raw materials.

[0042] The present invention preferably adds the original aluminum ingot, Mn source, Cr source and Ti source into the smelting furnace for melting, and when the melt temperature rises to 780-810°C, adds AlSc2 intermediate alloy, and the reaction time is ≥40min. When the melt temperature drops to 730-750°C, adds the original aluminum ingot with Al content of 99.95% or above and ALZr4 intermediate alloy to obtain alloy aluminum liquid.

[0043] After obtaining the alloy aluminum liquid, the present invention sequentially performs furnace refining, online degassing and plate filtration on the alloy aluminum liquid to purify the melt.

[0044] In the present invention, the furnace refining preferably first adopts powder spray refining, blowing the granular refining agent into the bottom of the melt to achieve the effect of degassing and slag removal, and then the alloy aluminum liquid is subjected to T-type refining, artificially introducing Ar gas, or a mixed gas of Ar gas and Cl2 gas, for refining.

[0045] In the present invention, the time of the powder spray refining is preferably 15 to 20 minutes, more preferably 16 to 18 minutes; the time of the T-type refining is preferably 13 to 18 minutes, more preferably 15 to 16 minutes; the gas flow rate of the T-type refining is preferably 3 to 5 L / min, more preferably 4 to 5 L / min.

[0046] In the present invention, the online degassing preferably adopts double rotor rotary degassing, and adopts argon or argon chlorine + chlorine mixed gas refining, and the gas flow rate of the online degassing is preferably 3-4m 3 / h, and after online degassing, a melt with hydrogen content reduced to less than 0.15ml / 100gAl was obtained.

[0047] In the present invention, the plate-type filtration adopts a double-stage filtration ceramic filter plate, the filtration accuracy of the first-stage ceramic filter plate is not less than 40PPI, and the filtration accuracy of the second-stage ceramic filter plate is not less than 50PPI.

[0048] After melt purification is completed, in order to refine the grain structure, the present invention uses AlTi5B1 wire online for grain refinement, and the amount of the AlTi5B1 wire is preferably 1.2-1.6 kg / t, more preferably 1.3-1.5 kg / t, and most preferably 1.4-1.5 kg / t.

[0049] After grain refinement, casting is performed. In the present invention, the casting speed is preferably 90 to 95 mm / min, more preferably 92 to 93 mm / min, and the water flow rate is preferably 140 to 160 m 3 / h, more preferably 145 to 155 m / h 3 / h, most preferably 150-155m 3 / h, the aluminum liquid temperature at the end of the flow disk is preferably 695-715°C, more preferably 700-710°C, and the water temperature is preferably 18-30°C, more preferably 20-25°C.

[0050] After the melt is cast, an ingot is obtained. In order to eliminate the ingot stress, reduce the segregation of the ingot and obtain a dispersedly distributed compound, the present invention performs a low-temperature homogenization annealing heat treatment, i.e., a soaking treatment, on the ingot. The heating rate of the soaking treatment is preferably 50 to 100°C / h, more preferably 60 to 90°C / h, and most preferably 70 to 80°C / h. The heating time of the soaking treatment is preferably 3 to 6 hours, more preferably 4 to 5 hours. The holding temperature of the soaking treatment is preferably 300 to 350°C, more preferably 320 to 340°C, and the holding time of the soaking treatment is preferably 10 to 15 hours, more preferably 12 to 14 hours.

[0051] The present invention also provides a round ingot for 5XXX aluminum alloy profiles, which is prepared according to the preparation method described above, and the chemical composition of the round ingot is as follows:

[0052] Si≤0.10%, Fe≤0.12%, Cu≤0.10%, Mg4.0~5.0%, Mn0.2~0.7%, Zn0.05~0.15%, Cr0.05~0.15%, Zr0.05~0.15%, Ti0.05~0.15%, Sc0.15~0.25%, and the balance is Al.

[0053] The invention provides a method for preparing a round ingot for a 5XXX aluminum alloy profile, comprising batching, smelting, solution purification, grain refinement, casting, and soaking treatment; batching is performed according to the following chemical composition ratio of the round ingot: Si 0.06%, Fe 0.06%, Cu 0.02%, Mg 4.38%, Mn 0.61%, Zn 0.10%, Cr 0.10%, Zr 0.08%, Ti 0.10%, Sc 0.22%, and the balance is Al; during the smelting process, the melt temperature is raised to 78 0~810℃, add Sc source, reaction time ≥40min, melt temperature drops to 730~750℃, then add Mg source and Zr source, and the rest are added with the furnace; the melt purification includes furnace refining, online degassing and plate filtration; the grain refinement adopts AlTi5B1 wire for grain refinement, and the dosage is 1.2~1.6kg / t; the heating rate of the heat treatment is 50~100℃ / h, the heating time is 3~6h, the insulation temperature is 300~350℃, and the insulation time is 10~15h. The present invention adjusts the chemical composition of the alloy by adding Sc and Zr elements, first, the fine grain strengthening produced by the primary Al3(Sc, Zr) particles; second, the dispersion strengthening produced by the precipitation of secondary Al3(Sc, Zr) particles during the homogenization process; third, the substructure strengthening caused by the Al3(Sc, Zr) particles inhibiting the recrystallization during the subsequent processing heat treatment, etc., which can significantly improve the strength of the alloy. The present invention optimizes the grain refining process to ensure that the original grains of the ingot are fine; adopts a low-temperature soaking treatment method to obtain a product ingot with small segregation, dispersed distribution of compounds, uniform and fine structure, improve the metallurgical quality of 5XXX aluminum alloy round ingots, and achieve the goal of improving the comprehensive performance of profiles.

[0054] In order to further illustrate the present invention, a method for preparing a round ingot for a 5XXX aluminum alloy profile provided by the present invention is described in detail below in conjunction with embodiments, but it should not be construed as limiting the scope of protection of the present invention.

[0055] Example 1

[0056] Chemical composition: Si0.06%, Fe0.06%, Cu0.02%, Mg4.38%, Mn0.61%, Zn0.10%, Cr0.10%, Zr0.08%, Ti0.10%, Sc0.22%, and the balance is Al.

[0057] Batching and smelting: Use raw aluminum ingots with Al99.95% or higher grade, intermediate alloys, pure metals, and additives. Mn elements are batched with aluminum-based Mn agents, Mg and Zn elements are batched with pure metals, and Mn, Cr, Zr, and Ti are batched with intermediate alloys. The raw aluminum ingots and intermediate alloys such as AlMn15, AlCr4, and AlTi4 are added to the smelting furnace for melting. When the melt temperature rises to 785°C, add the AlSc2 intermediate alloy, and the reaction time is 40 minutes. When the melt temperature drops to 734°C, add Mg ingots with a purity of 99.99% and AlZr4 intermediate alloys to obtain alloy aluminum liquid with elements that meet the requirements of the present invention.

[0058] Melt purification: The smelting furnace performs powder spray refining on the alloy aluminum liquid. The powder spray refining time is 15 minutes. The powder spray refining equipment is used to blow the granular refining agent into the bottom of the melt to achieve the effect of degassing and slag removal. The static furnace performs T-type refining on the alloy aluminum liquid. Ar gas and Cl2 gas mixture are manually introduced. The gas flow rate is 3.5L / min and the refining time is 15min. The online degassing uses double rotor rotation degassing for the alloy aluminum liquid passing through the box at a certain rate. The argon gas flow rate is 3.5m 3 / h, and obtain the alloy aluminum liquid with liquid hydrogen content of 0.131ml / 100gAl. After degassing, it is filtered using a 40+50PP ceramic filter plate.

[0059] Grain refinement: The present invention adopts AlTi5B1 wire online for grain refinement, using 1.4kg / t, ingot grain level 1.

[0060] Casting: Ingot specifications: diameter 172mm, casting 37 ingots, casting speed 90mm / min, water flow 158m 3 / h, the aluminum liquid temperature at the end of the flow plate is 695~715℃, and the cooling water temperature is 24℃

[0061] Heat annealing: The ingot is subjected to low temperature homogenization annealing treatment. The ingot of the present invention has a heating time of 4.5 hours, a holding temperature of 350°C, and a holding time of 12 hours.

[0062] Mechanical properties after extrusion:

[0063] The ingot has a first-grade grain size, fine grains, fine compounds and dispersed distribution. After extrusion, the yield strength is 310MPA and the elongation is 13%.

[0064] Example 2

[0065] Chemical composition: Si0.04%, Fe0.10%, Cu0.01%, Mg4.48%, Mn0.65%, Zn0.09%, Cr0.10%, Zr0.08%, Ti0.08%, Sc0.21%, and the balance is Al.

[0066] Batching and smelting: The present invention uses raw aluminum ingots with a grade of Al99.95% or above, intermediate alloys, pure metals, and additives. Mn elements are batched with aluminum-based Mn agents, Mg and Zn elements are batched with pure metals, and Mn, Cr, Zr, and Ti are batched with intermediate alloys. The raw aluminum ingots and intermediate alloys such as AlMn15, AlCr4, and AlTi4 are added to a smelting furnace for melting. When the melt temperature rises to 797°C, AlSc2 intermediate alloy is added, and the reaction time is 50 minutes. When the melt temperature drops to 745°C, Mg ingots with a purity of 99.99% and AlZr4 intermediate alloy are added to obtain alloy aluminum liquid whose elements meet the requirements of the present invention.

[0067] Melt purification: The smelting furnace performs powder spray refining on the alloy aluminum liquid. The powder spray refining time is 20 minutes. The powder spray refining equipment is used to blow the granular refining agent into the bottom of the melt to achieve the effect of degassing and slag removal. The static furnace performs T-type refining on the alloy aluminum liquid. Ar gas and Cl2 gas mixture are manually introduced. The gas flow rate is 4.5L / min and the refining time is 15min. The online degassing uses double rotors to degas the alloy aluminum liquid passing through the box at a certain rate. The argon flow rate is 3.5m 3 / h, and obtain the alloy aluminum liquid with liquid hydrogen content of 0.136ml / 100gAl. After degassing, it is filtered using a 40+50PP ceramic filter plate.

[0068] Grain refinement: The present invention adopts AlTi5B1 wire online for grain refinement, using 1.4kg / t, ingot grain level 1.

[0069] Casting: Ingot specifications: diameter 172mm, casting 40 ingots, casting speed 92mm / min, water flow 160m3 / h, aluminum liquid temperature at the end of the flow plate 695~715℃, cooling water temperature 23℃

[0070] Heat annealing: The ingot is subjected to low temperature homogenization annealing treatment. The ingot of the present invention has a heating time of 5 hours, a holding temperature of 350°C, and a holding time of 12 hours.

[0071] Mechanical properties after extrusion:

[0072] The ingot grain size is first grade, the grains are fine, the compounds are fine and dispersed, the extruded profile has a yield strength of 322MPA and an elongation of 14%.

[0073] Example 3

[0074] Chemical composition: Si0.025%, Fe0.032%, Cu0.01%, Mg4.59%, Mn0.66%, Zn0.046%, Cr0.10%, Zr0.10%, Ti0.075%, Sc0.24%, and the balance is Al.

[0075] Batching and smelting: The present invention uses raw aluminum ingots with a grade of Al99.95% or above, intermediate alloys, pure metals, and additives. Mn elements are batched with aluminum-based Mn agents, Mg and Zn elements are batched with pure metals, and Mn, Cr, Zr, and Ti are batched with intermediate alloys. The raw aluminum ingots and intermediate alloys such as AlMn15, AlCr4, and AlTi4 are added to a smelting furnace for melting. When the melt temperature rises to 802°C, AlSc2 intermediate alloys are added, and the reaction time is 50 minutes. When the melt temperature drops to 747°C, Mg ingots with a purity of 99.99% and AlZr4 intermediate alloys are added to obtain alloy aluminum liquid whose elements meet the requirements of the present invention.

[0076] Melt purification: The smelting furnace performs powder spray refining on the alloy aluminum liquid. The powder spray refining time is 18 minutes. The powder spray refining equipment is used to blow the granular refining agent into the bottom of the melt to achieve the effect of degassing and slag removal. The static furnace performs furnace bottom air brick refining on the alloy aluminum liquid. The gas introduced is Ar gas. The gas flow rate is 12-15L / min / block and the refining time is 30 minutes. The online degassing uses double rotors to degas the alloy aluminum liquid passing through the box at a certain rate. The argon gas flow rate is 2.6-3.6m 3 / h, and obtain the alloy aluminum liquid with liquid hydrogen content of 0.120ml / 100gAl. After degassing, filter with 40+50PP ceramic filter plate.

[0077] Grain refinement: The present invention adopts AlTi5B1 wire online for grain refinement, using 1.4kg / t, ingot grain level 1.

[0078] Casting: Ingot specifications: diameter 172mm, casting 40 ingots, casting speed 94mm / min, water flow 158m3 / h, aluminum liquid temperature at the end of the flow plate 695~715℃, cooling water temperature 22℃

[0079] Heat annealing: The ingot is subjected to low temperature homogenization annealing treatment. The ingot of the present invention has a heating time of 4.8 hours, a holding temperature of 350°C, and a holding time of 12 hours.

[0080] Mechanical properties after extrusion:

[0081] The ingot grain size is first grade, the grains are fine, the compounds are fine and dispersed, the extruded profile has a yield strength of 315MPA and an elongation of 14.5%.

[0082] Comparative Example 1

[0083] Chemical composition: Si0.06%, Fe0.13%, Cu0.02%, Mg4.36%, Mn0.66%, Zn0.02%, Cr0.08%, Zr0.04%, Ti0.02%, the balance is Al

[0084] The rest of the production process is the same as in Example 3

[0085] Heat annealing: The ingot is subjected to low temperature homogenization annealing treatment. The ingot of the present invention has a heating time of 6.5 hours, a holding temperature of 470°C, and a holding time of 24 hours.

[0086] Mechanical properties after extrusion:

[0087] Extruded profile, yield strength 178MPA, elongation 19%.

[0088] Comparative Example 2

[0089] A round ingot for 5XXX aluminum alloy profiles was prepared according to the method in Example 1, except that a high-temperature homogenization annealing treatment was used in the equalization step of Comparative Example 2, and the holding temperature of the high-temperature homogenization annealing treatment was 470° C. and the holding time was 24 h.

[0090] In Example 1, after low-temperature homogenization treatment, Al3(Sc, Zr) particles are uniformly precipitated in the ingot structure, with small size and uniform distribution. Figure 1 and Figure 2 As shown. In comparative example 2, the Al3(Sc, Zr) particles in the ingot structure after treatment are coarsened. Figure 3 and Figure 4 Therefore, the low temperature homogenization treatment system is better.

[0091] Comparative Example 3

[0092] Chemical composition: Si0.025%, Fe0.032%, Cu0.01%, Mg4.59%, Mn0.66%, Zn0.046%, Cr0.10%, Zr0.10%, Ti0.075%, Sc0.24%, and the balance is Al.

[0093] Batching and smelting: The present invention uses raw aluminum ingots with a grade of Al99.95% or above, intermediate alloys, pure metals, and additives. Mn elements are batched with aluminum-based Mn agents, Mg and Zn elements are batched with pure metals, and Mn, Cr, Zr, and Ti are batched with intermediate alloys. The raw aluminum ingots and intermediate alloys such as AlMn15, AlCr4, and AlTi4 are added to a smelting furnace for melting. When the melt temperature rises to 735°C, AlSc2 intermediate alloys are added, and the reaction time is 50 minutes. When the melt temperature drops to 747°C, Mg ingots with a purity of 99.99% and AlZr4 intermediate alloys are added to obtain alloy aluminum liquid whose elements meet the requirements of the present invention.

[0094] The rest of the production process is the same as in Example 3

[0095] In this comparative example 3, AlSc2 master alloy was added at a low temperature of 735°C, and the primary phase in the ingot structure was seriously aggregated. Figure 5 and Figure 6 As shown. In Example 3, the primary phase of the AlSc2 master alloy added at 802°C is more finely distributed and dispersed. Figure 7 and Figure 8 Therefore, the process of adding AlSc2 master alloy at high temperature is better.

[0096] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a round ingot for a 5XXX aluminum alloy profile, comprising batching, smelting, solution purification, grain refinement, casting, and soaking treatment; The ingredients are prepared according to the following chemical composition ratio of the round ingot: Si≤0.10%, Fe≤0.12%, Cu≤0.10%, Mg4.0~5.0%, Mn0.2~0.7%, Zn0.05~0.15%, Cr0.05~0.15%, Zr0.05~0.15%, Ti0.05~0.15%, Sc0.15~0.25%, the balance is Al; During the smelting process, the melt temperature rises to 780-810°C, the Sc source is added, the reaction time is ≥40min, the melt temperature drops to 730-750°C, and then the Mg source and Zr source are added, and the rest are added with the furnace; The melt purification includes furnace refining, online degassing and plate filtration; The grain refinement adopts AlTi5B1 wire for grain refinement, and the amount used is 1.2-1.6kg / t; The heating rate of the heat treatment is 50-100°C / h, the heating time is 3-6h, the insulation temperature is 300-350°C, and the insulation time is 10-15h.

2. The preparation method according to claim 1, characterized in that: In the ingredients, the Mg source is metal Mg, the Zn source is metal Zn, the Mn source, Cr source, Zr source, Ti source and Sc source are intermediate alloys containing Mn, Cr, Zr, Ti and Sc respectively, and the Al source is original aluminum ingots with an Al content of 99.95% or above.

3. The preparation method according to claim 2, characterized in that: The Mn source is AlMn15, the Cr source is AlCr4, the Zr source is ALZr4, the Ti source is AlTi4, and the Sc source is AlSc2.

4. The preparation method according to claim 1, characterized in that: The furnace refining first adopts powder spray refining, and then adopts argon gas or argon-chlorine mixed gas refining.

5. The preparation method according to claim 4, characterized in that: In the furnace refining, the powder spray refining time is 15 to 20 minutes; the flow rate of the argon gas or argon-chlorine mixed gas is 3 to 5 L / min.

6. The preparation method according to claim 1, characterized in that: The online degassing adopts argon or argon + chlorine mixed gas refining to reduce the hydrogen content of the melt to less than 0.15ml / 100gAl.

7. The preparation method according to claim 6, characterized in that: The online degassing adopts double rotor rotary degassing, and the gas flow rate of the online degassing is 3-4m 3 / h.

8. The preparation method according to claim 1, characterized in that: The plate filtration adopts a two-stage filtration ceramic filter plate, the filtration accuracy of the first-stage ceramic filter plate is not less than 40PPI, and the filtration accuracy of the second-stage ceramic filter plate is not less than 50PPI.

9. The preparation method according to claim 1, characterized in that: The casting speed is 90-95 mm / min, and the water flow rate is 140-160 m 3 / h, the aluminum liquid temperature at the end of the flow plate is 695~715℃, and the water temperature is 18~30℃.

10. A round ingot for 5XXX aluminum alloy profiles, prepared according to the preparation method according to any one of claims 1 to 9.

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