A method of manufacturing an aluminum alloy slab

Abstract

The application relates to a manufacturing method of an aluminum alloy flat ingot and relates to the field of a manufacturing method of an aluminum alloy flat ingot. In order to solve the technical problem that the strength of a 5xxx series aluminum alloy prepared by an existing method does not meet the standard, the application provides the method, which comprises the following steps: one, ingredient preparation; two, smelting; and three, casting. The application controls the content of Zr and Sc, so that the alloy has excellent mechanical properties. The finished product rate of the ingot prepared by the method is improved, and the problem that the strength and other indexes of the material prepared by the existing method do not meet the requirements is solved. The application is used for preparing an aluminum alloy flat ingot.

Description

Technical Field

[0001] This invention relates to the field of a method for manufacturing aluminum alloy flat castings. Background Technology

[0002] The main constituent elements of 5xxx series aluminum alloys are Al and Mg. These alloys generally possess moderate strength, certain plasticity, excellent wear resistance, corrosion resistance, and good weldability, making them commonly used to process important components such as pistons, aircraft skins, and forgings. To improve their overall performance, researchers have various options, among which microalloying is widely used. Sc, as one of the most effective strengthening elements in aluminum alloy microalloying, is extensively used to improve the mechanical properties of aluminum alloys. However, the Al3Sc particles formed by Sc and Al have poor thermal stability and tend to grow and coarsen during heat treatment. Although the addition of Zr can solve this problem, the addition of Zr also reduces the elongation of the alloy, so its addition amount needs to be controlled. Summary of the Invention

[0003] This invention addresses the technical problem of insufficient strength in existing methods for preparing 5xxx series aluminum alloys by providing a method for manufacturing flat aluminum alloy ingots.

[0004] A method for manufacturing an aluminum alloy flat ingot, characterized by the following steps:

[0005] I. Raw Materials: Based on the elemental mass percentages: Si < 0.20%, Fe < 0.25%, Cu < 0.20%, Mn: 0.15%–0.20%, Mg: 4.5%–5.0%, Cr < 0.10%, Zn < 0.20%, Ti: 0.05%–0.15%, Zr: 0.10%–0.12%, Sc: 0.16%–0.20%, and the balance aluminum (the individual impurity element content is allowed to be less than 0.05%, and the total impurity element content is allowed to be less than 0.15%), weigh out high-purity aluminum ingots, metallic Cu, metallic Mg, metallic Zn, AlTi6 master alloy, AlZr3 master alloy, and AlSc3 master alloy as smelting raw materials;

[0006] II. Melting: The smelting raw materials weighed in step one are added to high-purity aluminum ingots in sequence, followed by metallic Cu, metallic Zn, AlZr3 master alloy and AlSc3 master alloy, and then metallic Mg and AlTi6 master alloy. The mixture is then loaded into a natural gas melting furnace and melted into a molten body. The smelting temperature is controlled at 750-820℃ during the feeding process. After the feeding is completed, the molten body temperature is maintained at 800℃, and the mixture is stirred once every 20 minutes for a total of 2 times. Samples are taken using coated tools, and the molten body temperature is ≥750℃ at the time of sampling. The chemical composition is analyzed. After the chemical composition is qualified, the mixture is covered with flux to obtain the alloy melt.

[0007] III. Casting: The alloy melt obtained in step II is introduced into a static furnace at a temperature of 740-780 DEG C, argon-chlorine mixed gas is introduced for 30 minutes, then the alloy melt in the static furnace is allowed to stand for 30 minutes, then the refined alloy melt is first introduced into an on-line degassing device, then into a filtering device, and then into a crystallizer by flow disc injection under the condition of on-line seeding of AlTi5B1A wire, semi-continuous casting is carried out, the casting speed is controlled to be 42-48 mm / min, the casting temperature is 710-740 DEG C, the casting cooling water pressure is 0.01-0.05 MPa, and the aluminum alloy flat ingot is obtained, and the preparation is completed.

[0008] The application provides a preparation method of an aluminum alloy flat ingot, the content of main component elements is adjusted, and the method is characterized in that a certain amount of Zr and Sc is added at the same time, so that L12 type particles Al3(Sc, Zr) (L12) are precipitated in the aluminum alloy; and the process parameters of smelting and casting are designed, so that the generation of an oxide film and surface defects is avoided, the mechanical properties of the alloy are greatly improved, the plasticity of the alloy is good, and the comprehensive performance of the alloy is improved.

[0009] In the aluminum alloy, a certain content of Zr and Sc is added. Zr, Sc and Al combine to form Al3(Sc, Zr) (L12) type particles. The shape of the particles is composed of an A13Sc inner core and an A13Zr outer shell, and the main strengthening mechanism is precipitation strengthening, fine-grain strengthening and substructure strengthening. The particles have good thermal stability and smaller lattice mismatch, can form a good coherent relationship due to the similar structure to the Al matrix, have a significant effect on grain refinement, greatly improve the mechanical properties of the alloy, can pin dislocations and grain boundaries, hinder the movement of dislocations and the migration of grain boundaries, and have a good fine-grain strengthening and substructure strengthening effect; and due to the segregation of Sc and Zr to the center and the outer edge of the dendrite during the solidification of the alloy, a relatively uniform distribution of precipitates can be finally obtained.

[0010] A small amount of Ti and B is added, which can significantly refine the alloy grains, reduce the crack tendency of the alloy, improve the strength of the alloy to a certain extent, and obtain good plasticity.

[0011] The application has the following beneficial effects:

[0012] The application designs a component of aluminum alloy, by adding a certain amount of Zr and Sc, the interaction of the two makes the alloy obtain excellent mechanical properties. According to the characteristics of the alloy, the adding sequence during smelting is designed, so that they can be uniformly distributed in the melt; the argon-chlorine mixed gas is blown for refining and the melt is statically placed for a sufficient time, so that the alkali metals and other harmful elements in the melt can be effectively reduced; the melt flows into the on-line degassing device, so that hydrogen can be effectively removed, and the possibility of defects such as oxide film and air hole is greatly reduced. The yield of the cast ingot obtained by the above method is improved, and the problem that the strength index of the material prepared by the existing method does not meet the requirements is solved.

[0013] The application is used for preparing aluminum alloy flat cast ingot. DETAILED DESCRIPTION

[0014] Specific embodiment one: the manufacturing method of the aluminum alloy flat cast ingot, the method comprises the following steps:

[0015] I. batching: according to the mass percentage of elements: Si < 0.20%, Fe < 0.25%, Cu < 0.20%, Mn: 0.15% ~ 0.20%, Mg: 4.5% ~ 5.0%, Cr < 0.10%, Zn < 0.20%, Ti: 0.05% ~ 0.15%, Zr: 0.10% ~ 0.12%, Sc: 0.16% ~ 0.20% and the balance of aluminum, high-purity aluminum ingot, metal Cu, metal Mg, metal Zn, AlTi6 intermediate alloy, AlZr3 intermediate alloy and AlSc3 intermediate alloy are weighed as smelting raw materials;

[0016] II. smelting: the smelting raw materials weighed in step I are sequentially added into the natural gas melting furnace in the order of high-purity aluminum ingot, then metal Cu, metal Zn, AlZr3 intermediate alloy and AlSc3 intermediate alloy, and then metal Mg and AlTi6 intermediate alloy, and the melt is formed by melting, the smelting temperature is controlled to be 750 ~ 820 ℃ during the feeding process; after the feeding is completed, the melt temperature is maintained at 800 ℃, and the melt is stirred once every 20 min, and the melt is stirred for a total of 2 times; the tool coated with a coating is used for sampling, the melt temperature is greater than or equal to 750 ℃ during sampling, the chemical composition is analyzed, and the alloy melt is obtained after the chemical composition is qualified and the flux is covered;

[0017] III. Casting: The alloy melt obtained in step II is introduced into a static furnace at a temperature of 740-780℃, argon-chlorine mixed gas is introduced for 30 minutes for refining, then the alloy melt in the static furnace is allowed to stand for 30 minutes, and then the refined alloy melt is first introduced into an on-line degassing device and then into a filtering device, and then is injected into a crystallizer through a flow disc under the condition of on-line seeding of AlTi5B1A wire to perform semi-continuous casting, the casting speed is controlled to be 42-48 mm / min, the casting temperature is 710-740℃, the casting cooling water pressure is 0.01-0.05 MPa, and the aluminum alloy flat ingot is obtained, and the preparation is completed.

[0018] Specific embodiment II: The difference between this embodiment and specific embodiment I is that the mass purity of the high-purity aluminum ingot in step I is 99.99%. The others are the same as specific embodiment I.

[0019] Specific embodiment III: The difference between this embodiment and specific embodiment I or II is that the mass content of Zr in the AlZr3 intermediate alloy in step I is 3%, and the rest is Al.

[0020] The mass content of Sc in the AlSc3 intermediate alloy is 3%, and the rest is Al. The others are the same as specific embodiment I or II.

[0021] Specific embodiment IV: The difference between this embodiment and one of specific embodiments I to III is that the melt temperature is above 800℃ when the AlSc3 intermediate alloy is added in step II. The others are the same as one of specific embodiments I to III.

[0022] Specific embodiment V: The difference between this embodiment and one of specific embodiments I to IV is that the flux covered in step II is composed of 40% KCl, 45% MgCl2, 8% BaCl2 and 7% NaCl+CaCl2 by mass percentage, and the addition amount of the solvent is 5 kg / ton of melt. The others are the same as one of specific embodiments I to IV.

[0023] Specific embodiment VI: The difference between this embodiment and one of specific embodiments I to V is that the composition of the argon-chlorine mixed gas introduced in step III is 95% argon and 5% chlorine by volume content.

[0024] The rate of the argon-chlorine mixed gas introduced is 0.06-0.018 m 3 / h. The others are the same as one of specific embodiments I to V.

[0025] Specific embodiment VII: The difference between this embodiment and one of specific embodiments I to VI is that the shape of the melt injected into the crystallizer in step III is a rectangle of 420 mm x 1620 mm. The others are the same as one of specific embodiments I to VI.

[0026] Eighth Embodiment: The difference between this embodiment and any one of the first through seventh embodiments is that the precision of the ceramic sheet in the step three flowing filter device is 30 ppi + 50 ppi. The others are the same as any one of the first through seventh embodiments.

[0027] Ninth Embodiment: The difference between this embodiment and any one of the first through eighth embodiments is that the mass content of Ti in the AlTi5B1A wire in the step three in-line seeding is 5%, the mass content of B is 1%, and the rest is Al, and the control seeding speed is 370 mm / min. The others are the same as any one of the first through eighth embodiments.

[0028] Tenth Embodiment: The difference between this embodiment and any one of the first through ninth embodiments is that the size of the aluminum alloy flat ingot obtained by the step three semi-continuous casting is 420 mm x 1620 mm x (3000 mm ~ 6000 mm). The others are the same as any one of the first through ninth embodiments.

[0029] The content of the present application is not limited to the content of the above-mentioned embodiments, and the combination of one or more of the embodiments can also achieve the purpose of the present application.

[0030] Example One:

[0031] The present embodiment is a method for manufacturing an aluminum alloy flat ingot, which comprises the following steps:

[0032] I. According to the mass percentage of elements: Si < 0.20%, Fe < 0.25%, Cu < 0.20%, Mn: 0.17%, Mg: 4.7% ~ 5.0%, Cr < 0.10%, Zn < 0.20%, Ti: 0.10% ~ 0.15%, Zr: 0.10%, Sc: 0.18%, and the balance of aluminum, high-purity aluminum ingot, metal Cu, metal Mg, metal Zn, AlTi6 intermediate alloy, AlZr3 intermediate alloy and AlSc3 intermediate alloy are weighed as smelting raw materials;

[0033] II. The smelting raw materials weighed in step I are sequentially added into the natural gas melting furnace in the order of high-purity aluminum ingot, then metal Cu, metal Zn, AlZr3 intermediate alloy and AlSc3 intermediate alloy, and then metal Mg and AlTi6 intermediate alloy, and the molten bath is formed by melting, and the smelting temperature is controlled to be 750 ~ 820°C during the feeding process; After the feeding is completed, the molten bath temperature is maintained at 800°C, and each 20 min is stirred once, and a total of 2 times; The tool coated with paint is used for sampling, and the sampling temperature of the molten bath is 750°C, and the chemical composition is analyzed, and after the chemical composition is qualified, the alloy melt is obtained by covering the flux;

[0034] III. The alloy melt obtained in step II is introduced into a static furnace at a temperature of 750℃, argon-chlorine mixed gas is introduced for 30 minutes, and then the alloy melt in the static furnace is allowed to stand for 30 minutes. The refined alloy melt is first introduced into an on-line degassing device, and then into a filtering device. The alloy melt is then injected into a crystallizer through a flow plate under the condition of on-line seeding of AlTi5B1A wires to perform semi-continuous casting. The casting speed is controlled at 42 mm / min, the casting temperature is 720℃, the casting cooling water pressure is 0.03 MPa, and the aluminum alloy flat ingot is obtained.

[0035] The flux covered in step II is composed of 40% KCl, 45% MgCl2, 8% BaCl2 and 7% NaCl+CaCl2 by mass percentage, and the amount of addition is 5 kg / ton of melt.

[0036] The argon-chlorine mixed gas introduced in step III has a composition of 95% argon and 5% chlorine by volume.

[0037] The rate of the argon-chlorine mixed gas introduced in step III is 0.06-0.018 m 3 / h.

[0038] The precision of the ceramic sheet introduced into the filtering device in step III is 30 ppi+50 ppi.

[0039] The mass content of Ti in the AlTi5B1A wires seeded on-line in step III is 5%, the mass content of B is 1%, and the balance is Al. The seeding speed is controlled at 370 mm / min.

[0040] The aluminum alloy flat ingot obtained in this example has qualified chemical composition and flaw detection, no oxide film, no surface cracks, no slag inclusion and other defects, and the strength is improved by 38 MPa.

[0041] Example II

[0042] The manufacturing method of the aluminum alloy flat ingot in this example comprises the following steps:

[0043] I. The high-purity aluminum ingot, metal Cu, metal Mg, metal Zn, AlTi6 intermediate alloy, AlZr3 intermediate alloy and AlSc3 intermediate alloy are weighed as smelting raw materials according to the mass percentage of the following elements: Si <0.15%, Fe <0.20%, Cu <0.15%, Mn: 0.15-0.17%, Mg: 4.5%-4.8%, Cr <0.10%, Zn <0.20%, Ti: 0.10%-0.15%, Zr: 0.12%, Sc: 0.20% and the balance of aluminum.

[0044] II. The smelting raw materials weighed in step I are sequentially added into a natural gas melting furnace in the order of high-purity aluminum ingot, metal Cu, metal Zn, AlZr3 intermediate alloy and AlSc3 intermediate alloy, and then metal Mg and AlTi6 intermediate alloy, to form a melt, with the smelting temperature controlled at 750-820 ℃ during the feeding process; after the feeding is completed, the melt temperature is maintained at 810 ℃, with stirring once every 20 min, for a total of 2 times; the sample is taken using a coated tool, with the melt temperature being 775 ℃ during sampling, and the chemical composition is analyzed; after the chemical composition is qualified, the alloy melt is obtained by covering a flux;

[0045] III. The alloy melt obtained in step II is introduced into a static furnace at a temperature of 760 ℃, argon-chlorine mixed gas is introduced for 30 min for refining, and then the alloy melt refined in the static furnace is first flowed into an online degassing device, and then flowed into a filtering device, and then injected into a crystallizer through a flow disc under the condition of online seeding of AlTi5B1A wire for semi-continuous casting, with the casting speed controlled at 46 mm / min, the casting temperature controlled at 725 ℃, and the casting cooling water pressure controlled at 0.025 MPa, to obtain the aluminum alloy flat ingot, and the preparation is completed.

[0046] The flux covered in step II is composed of 40% KCl, 45% MgCl2, 8% BaCl2 and 7% NaCl+CaCl2 by mass percentage, and the addition amount is 5 kg / ton of melt.

[0047] The composition of the argon-chlorine mixed gas introduced in step III is 95% argon and 5% chlorine by volume content.

[0048] The flow rate of the argon-chlorine mixed gas introduced in step III is 0.06-0.018 m 3 / h.

[0049] The precision of the ceramic sheet flowed into the filtering device in step III is 30 ppi+50 ppi.

[0050] In the online seeding of AlTi5B1A wire in step III, the mass content of Ti is 5%, the mass content of B is 1%, and the balance is Al, with the seeding speed controlled at 370 mm / min.

[0051] The aluminum alloy flat ingot obtained in this example has qualified chemical composition, qualified flaw detection, no oxide film, and no surface cracks, slag inclusions and other defects, with the strength improved by 43 MPa.

[0052] Example Three:

[0053] The manufacturing method of the aluminum alloy flat ingot in this example comprises the following steps:

[0054] I. According to the element mass percentage: Si < 0.10%, Fe < 0.15%, Cu < 0.20%, Mn: 0.15-0.18%, Mg: 4.7%-4.9%, Cr < 0.10%, Zn < 0.20%, Ti: 0.12%-0.15%, Zr: 0.12%, Sc: 0.16%, and the balance of aluminum, high-purity aluminum ingot, metal Cu, metal Mg, metal Zn, AlTi6 intermediate alloy, AlZr3 intermediate alloy and AlSc3 intermediate alloy are weighed as smelting raw materials;

[0055] II. The smelting raw materials weighed in step I are sequentially added into the natural gas melting furnace in the order of high-purity aluminum ingot, then metal Cu, metal Zn, AlZr3 intermediate alloy and AlSc3 intermediate alloy, and then metal Mg and AlTi6 intermediate alloy, and melted into a melt, and the smelting temperature is controlled to be 750-820°C during the feeding process; after the feeding is completed, the melt temperature is maintained at 815°C, and stirring is performed once every 20 min, for a total of 2 times; sampling is performed using a coated tool, the melt temperature during sampling is 800°C, chemical composition is analyzed, and after the chemical composition is qualified, the alloy melt is obtained after being covered with a flux;

[0056] III. The alloy melt obtained in step II is introduced into a static furnace at a temperature of 770°C, argon-chlorine mixed gas is introduced for 30 min for refining, and then the alloy melt refined in the static furnace is first flowed into an online degassing device, and then flowed into a filtering device, and then injected into a crystallizer through a flow disc under the condition of online seeding of AlTi5B1A wire for semi-continuous casting, the casting speed is controlled to be 48 mm / min, the casting temperature is 730°C, and the casting cooling water pressure is 0.035 MPa, to obtain the aluminum alloy flat ingot, and the preparation is completed.

[0057] The flux covered in step II is composed of 40% KCl, 45% MgCl2, 8% BaCl2 and 7% NaCl+CaCl2 by mass percentage, and the addition amount is 5 kg / ton of melt.

[0058] The composition of the argon-chlorine mixed gas introduced in step III is 95% argon and 5% chlorine by volume content.

[0059] The flow rate of the argon-chlorine mixed gas introduced in step III is 0.06-0.018 m 3 / h.

[0060] The precision of the ceramic sheet flowed into the filtering device in step III is 30 ppi+50 ppi.

[0061] The mass content of Ti in the AlTi5B1A wire seeded online in step III is 5%, the mass content of B is 1%, and the balance is Al, and the seeding speed is controlled to be 370 mm / min.

[0062] The aluminum alloy flat ingot obtained by the embodiment has qualified chemical composition, qualified flaw detection, no oxide film, and no defects such as cracks and slag inclusions on the surface, and the strength is increased by 40 MPa.

[0063] The above content cannot be regarded as the limitation of the embodiments of the present application, and for those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or substitutions can be made, which should be regarded as belonging to the patent protection range determined by the submitted claims.

Claims

1. A method for manufacturing an aluminum alloy flat casting ingot with a Mg content of 4.5% to 5.0%, characterized in that... The method includes the following steps: I. Raw Materials: Based on the elemental mass percentages: Si < 0.20%, Fe < 0.25%, Cu < 0.20%, Mn: 0.15%–0.20%, Mg: 4.5%–5.0%, Cr < 0.10%, Zn < 0.20%, Ti: 0.05%–0.15%, Zr: 0.10%–0.12%, Sc: 0.16%–0.20%, and the balance aluminum, weigh out high-purity aluminum ingots, metallic Cu, metallic Mg, metallic Zn, AlTi6 master alloy, AlZr3 master alloy, and AlSc3 master alloy as smelting raw materials; II. Melting: The smelting raw materials weighed in step one are added to high-purity aluminum ingots in sequence, followed by metallic Cu, metallic Zn, AlZr3 master alloy and AlSc3 master alloy, and then metallic Mg and AlTi6 master alloy. The mixture is then loaded into a natural gas melting furnace and melted into a molten body. The smelting temperature is controlled at 750-820℃ during the feeding process. After the feeding is completed, the molten body temperature is maintained at 800℃, and the mixture is stirred once every 20 minutes for a total of 2 times. Samples are taken using coated tools, and the molten body temperature is ≥750℃ at the time of sampling. The chemical composition is analyzed. After the chemical composition is qualified, the mixture is covered with flux to obtain the alloy melt. III. Casting: The alloy melt obtained in step II is introduced into a holding furnace at a temperature of 740-780℃ and refined by argon-chlorine mixed gas for 30 minutes. Then it is held for 30 minutes. The refined alloy melt in the holding furnace is first flowed into an online degassing device, then into a filtration device, and then injected into a crystallizer through a flow plate under the condition of online seeding of AlTi5B1A wire for semi-continuous casting. The casting speed is controlled at 42mm / min-48mm / min, the casting temperature is 710-740℃, and the casting cooling water pressure is 0.01-0.05MPa to obtain the aluminum alloy flat ingot, thus completing the preparation. The flux used in step two consists of 40% KCl, 45% MgCl2, 8% BaCl2, and 7% NaCl+CaCl2 by mass percentage, with a solvent addition of 5 kg / ton of melt. In step three, the AlTi5B1A filament is seeded online with a Ti mass content of 5%, a B mass content of 1%, and the balance being Al, and the seeding speed is controlled at 370 mm / min.

2. The method for manufacturing an aluminum alloy flat ingot with a Mg content of 4.5% to 5.0% according to claim 1, characterized in that... The purity of the high-purity aluminum ingot in step one is 99.99%.

3. The method for manufacturing an aluminum alloy flat ingot with a Mg content of 4.5% to 5.0% according to claim 1, characterized in that... The AlZr3 master alloy described in step one contains 3% Zr by mass, with the remainder being Al; The AlSc3 master alloy contains 3% Sc by mass, with the remainder being Al.

4. The method for manufacturing an aluminum alloy flat ingot with a Mg content of 4.5% to 5.0% according to claim 1, characterized in that... When AlSc3 master alloy is added in step two, the melt temperature is above 800℃.

5. The method for manufacturing an aluminum alloy flat ingot with a Mg content of 4.5% to 5.0% according to claim 1, characterized in that... Step 3: Introduce an argon-chlorine mixed gas with a volume composition of 95% argon and 5% chlorine. The rate at which the argon-chlorine mixed gas is introduced is 0.06–0.018 m / s. 3 / h.

6. The method for manufacturing an aluminum alloy flat ingot with a Mg content of 4.5% to 5.0% according to claim 1, characterized in that... Step 3: The shape of the melt injection crystallizer is a rectangle of 420mm × 1620mm.

7. The method for manufacturing an aluminum alloy flat ingot with a Mg content of 4.5% to 5.0% according to claim 1, characterized in that... In step three, the ceramic discs flowing into the filter device have a resolution of 30ppi + 50ppi.

8. The method for manufacturing an aluminum alloy flat ingot with a Mg content of 4.5% to 5.0% according to claim 1, characterized in that... The dimensions of the aluminum alloy flat ingot obtained from the semi-continuous casting in step three are 420mm×1620mm×(3000mm~6000mm).