Manufacturing method of aluminum alloy flat cast ingot

Abstract

The invention discloses a manufacturing method of an aluminum alloy flat cast ingot, and relates to the field of manufacturing methods of aluminum alloy flat cast ingots. The technical problem that the strength of the 5xxx series aluminum alloy prepared through an existing method does not reach the standard is solved. The method comprises the following steps: 1, burdening; 2, smelting; and 3, casting. By controlling the content of Zr and Sc, the alloy has excellent mechanical properties. The yield of the cast ingot obtained 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 method is used for preparing the aluminum alloy flat cast ingot.

Description

Technical Field

[0001] The invention relates to the field of a method for manufacturing an aluminum alloy flat ingot. Background Art

[0002] The main components of 5xxx series aluminum alloys are Al and Mg. Most of their products have medium strength, certain plasticity, excellent wear resistance, corrosion resistance, good welding performance and other advantages. They are often used to process important parts such as pistons, aircraft skins, forgings, etc. In order to improve its comprehensive performance, researchers have a variety of options, among which microalloying is more widely used. Sc, as one of the best strengthening elements in aluminum alloy microalloying, is used in large quantities to improve the mechanical properties of aluminum alloys, but the Al3Sc particles formed by it and Al have poor thermal stability and are easy to grow and coarsen during heat treatment. Although the composite addition of Zr can solve this problem, the addition of Zr will also reduce the elongation of the alloy, so its addition amount needs to be controlled. Summary of the invention

[0003] The present invention aims to solve the technical problem that the strength of 5xxx series aluminum alloys prepared by the existing method does not meet the standard, and provides a method for manufacturing aluminum alloy flat ingots.

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

[0005] 1. Ingredients: 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 (the single content of impurity elements is allowed to be less than 0.05%, and the total content of impurity elements is less than 0.15%), weigh high-purity aluminum ingots, metal Cu, metal Mg, metal Zn, AlTi6 master alloy, AlZr3 master alloy and AlSc3 master alloy as smelting raw materials;

[0006] 2. Melting: first add the smelting raw materials weighed in step 1 to high-purity aluminum ingots in order, then add metal Cu, metal Zn, AlZr3 master alloy and AlSc3 master alloy, and then add metal Mg and AlTi6 master alloy into a natural gas melting furnace to melt into a melt. During the feeding process, the melting temperature is controlled to be 750-820°C; after the feeding is completed, the melt temperature is maintained at 800°C, and stirred once every 20 minutes, for a total of 2 times; use a coated tool to take samples, the melt temperature is ≥750°C during sampling, analyze the chemical composition, and after the chemical composition is qualified, cover it with flux to obtain an alloy melt;

[0007] 3. Casting: The alloy melt obtained in step 2 is introduced into a static furnace at a temperature of 740-780°C, and argon-chlorine mixed gas is introduced for refining for 30 minutes, and then the alloy melt refined in the static furnace is first flowed into an online degassing device, and then into a filtering device, and then injected into a crystallizer through a flow disk under the condition of online seeding of AlTi5B1A wire, and semi-continuous casting is performed, the casting speed is controlled to be 42mm / min-48mm / min, the casting temperature is 710-740°C, and the casting cooling water pressure is 0.01-0.05MPa, to obtain the aluminum alloy flat ingot, and the preparation is completed.

[0008] The present invention provides a method for preparing an aluminum alloy flat ingot, in which the contents of main constituent elements are adjusted. The method is characterized in that L12 type particles Al3 (Sc, Zr) (L12) type particles can be precipitated in the aluminum alloy by adding a certain amount of Zr and Sc at the same time; the process parameters for smelting and casting are designed, which not only avoids the generation of oxide film and surface defects, but also greatly improves the mechanical properties of the alloy, and at the same time has good plasticity, playing an important role in improving the comprehensive performance of the alloy.

[0009] A certain amount of Zr and Sc are added to the aluminum alloy. Zr, Sc and Al combine to form Al3(Sc, Zr)(L12) type particles. Its shape is composed of an A13Sc core and an A13Zr shell, and the main strengthening mechanisms are precipitation strengthening, grain refinement and substructure strengthening. It has good thermal stability and a smaller lattice mismatch. Because its structure is similar to that of the Al matrix, it can form a good coherence relationship, which has a significant effect on grain refinement and greatly improves the mechanical properties of the alloy; nanoscale Al3(Sc, Zr) can also pin dislocations and grain boundaries, hinder dislocation movement and grain boundary migration, and inhibit the recrystallization ability from becoming stronger, playing a good role in grain refinement and substructure strengthening; and because during the solidification process of the alloy, Sc and Zr are respectively concentrated in the center and outer edge of the dendrite, a relatively uniform distribution of precipitates can be obtained in the end.

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

[0011] Beneficial effects of the present invention:

[0012] The present invention designs a composition of an aluminum alloy, and by adding a certain amount of Zr and Sc, the interaction between the two enables the alloy to obtain excellent mechanical properties. The order of addition during smelting is designed according to the characteristics of the alloy, so that they can be evenly distributed in the melt; the introduction of argon-chlorine mixed gas refining and sufficient time of standing can effectively reduce the alkali metals and other harmful elements in the melt; the melt flows into an online degassing device, which can effectively remove hydrogen and greatly reduce the possibility of defects such as oxide film and pores. The finished product rate of the ingot obtained according to 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 invention is used for preparing aluminum alloy flat ingot. DETAILED DESCRIPTION

[0014] Specific implementation method 1: This implementation method is a method for manufacturing an aluminum alloy flat ingot, the method comprising the following steps:

[0015] 1. Ingredients: 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, weigh high-purity aluminum ingots, metal Cu, metal Mg, metal Zn, AlTi6 master alloy, AlZr3 master alloy and AlSc3 master alloy as smelting raw materials;

[0016] 2. Melting: first add the smelting raw materials weighed in step 1 to high-purity aluminum ingots in order, then add metal Cu, metal Zn, AlZr3 master alloy and AlSc3 master alloy, and then add metal Mg and AlTi6 master alloy into a natural gas melting furnace to melt into a melt. During the feeding process, the melting temperature is controlled to be 750-820°C; after the feeding is completed, the melt temperature is maintained at 800°C, and stirred once every 20 minutes, for a total of 2 times; use a coated tool to take samples, the melt temperature is ≥750°C during sampling, analyze the chemical composition, and after the chemical composition is qualified, cover it with flux to obtain an alloy melt;

[0017] 3. Casting: The alloy melt obtained in step 2 is introduced into a static furnace at a temperature of 740-780°C, and argon-chlorine mixed gas is introduced for refining for 30 minutes, and then the alloy melt refined in the static furnace is first flowed into an online degassing device, and then into a filtering device, and then injected into a crystallizer through a flow disk under the condition of online seeding of AlTi5B1A wire, and semi-continuous casting is performed, the casting speed is controlled to be 42mm / min-48mm / min, the casting temperature is 710-740°C, and the casting cooling water pressure is 0.01-0.05MPa, to obtain the aluminum alloy flat ingot, and the preparation is completed.

[0018] Specific implementation method 2: This implementation method is different from the specific implementation method 1 in that the mass purity of the high-purity aluminum ingot in step 1 is 99.99%. The rest is the same as the specific implementation method 1.

[0019] Specific implementation method three: This implementation method is different from specific implementation methods one or two in that: in step one, the Zr content of the AlZr3 master alloy is 3% by mass, and the rest is Al;

[0020] The mass content of Sc in the AlSc3 master alloy is 3%, and the rest is Al. The rest is the same as the first or second specific implementation.

[0021] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the melt temperature is above 800° C. when the AlSc3 master alloy is added in step 2. The rest is the same as specific embodiments 1 to 3.

[0022] Specific embodiment 5: This embodiment is different from specific embodiments 1 to 4 in that the flux covered in step 2 is composed of 40% KCl, 45% MgCl2, 8% BaCl2 and 7% NaCl+CaCl2 by mass percentage, and the amount of solvent added is 5kg / ton of melt. Others are the same as specific embodiments 1 to 4.

[0023] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that: in step 3, the argon-chlorine mixed gas is introduced with a volume content of 95% argon and 5% chlorine;

[0024] The rate of introducing argon-chlorine mixed gas is 0.06~0.018m 3 / h. The rest is the same as that of the first to fifth embodiments.

[0025] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that: the shape of the crystallizer in step 3 where the melt is injected is a rectangle of 420 mm×1620 mm. The rest is the same as specific embodiments 1 to 6.

[0026] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that the precision of the ceramic sheets flowing into the filter device in step 3 is 30ppi+50ppi. The rest is the same as specific embodiments 1 to 7.

[0027] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that: in step 3, the mass content of Ti in the online sowing AlTi5B1A wire is 5%, the mass content of B is 1%, and the balance is Al, and the sowing speed is controlled to be 370 mm / min. The rest is the same as specific embodiments 1 to 8.

[0028] Specific embodiment 10: This embodiment is different from specific embodiments 1 to 9 in that the size of the aluminum alloy flat ingot obtained by semi-continuous casting in step 3 is 420mm×1620mm×(3000mm~6000mm). Others are the same as specific embodiments 1 to 9.

[0029] The content of the present invention is not limited to the content of the above-mentioned embodiments. The combination of one or several specific embodiments can also achieve the purpose of the invention.

[0030] Embodiment 1:

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

[0032] 1. 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 ingots, metal Cu, metal Mg, metal Zn, AlTi6 master alloy, AlZr3 master alloy and AlSc3 master alloy are weighed as smelting raw materials;

[0033] 2. Add the smelting raw materials weighed in step 1 to high-purity aluminum ingots in order, then add metal Cu, metal Zn, AlZr3 master alloy and AlSc3 master alloy, and then add metal Mg and AlTi6 master alloy into a natural gas melting furnace to melt into a melt. During the feeding process, the smelting temperature is controlled to be 750-820°C; after the feeding is completed, the melt temperature is maintained at 800°C, and stirred once every 20 minutes, for a total of 2 times; use a coated tool to take samples, the melt temperature is 750°C during sampling, and the chemical composition is analyzed. After the chemical composition is qualified, it is covered with flux to obtain an alloy melt;

[0034] 3. The alloy melt obtained in step 2 is introduced into a static furnace at a temperature of 750°C, and an argon-chlorine mixed gas is introduced for refining for 30 minutes, and then the alloy melt refined in the static furnace is first flowed into an online degassing device, and then into a filtering device, and then injected into a crystallizer through a flow disk under the condition of online seeding of AlTi5B1A wire for semi-continuous casting. The casting speed is controlled to be 42 mm / min, the casting temperature is 720°C, and the casting cooling water pressure is 0.03 MPa to obtain the aluminum alloy flat ingot, thereby completing the preparation.

[0035] The flux used in step 2 is composed of 40% KCl, 45% MgCl2, 8% BaCl2 and 7% NaCl+CaCl2 by mass percentage, and the added amount is 5kg / ton of melt.

[0036] Step 3: introducing an argon-chlorine mixed gas having a volume content of 95% argon and 5% chlorine.

[0037] Step 3: The rate of introducing argon-chlorine mixed gas is 0.06-0.018 m / s. 3 / h.

[0038] Step 3: The precision of the ceramic sheet flowing into the filtration device is 30ppi+50ppi.

[0039] Step 3: Online seeding of AlTi5B1A wire in which the mass content of Ti is 5%, the mass content of B is 1%, and the balance is Al. The seeding speed is controlled to 370 mm / min.

[0040] The aluminum alloy flat ingot obtained in this embodiment has qualified chemical composition, qualified flaw detection, no oxide film, no surface defects such as cracks and slag inclusions, and the strength is increased by 38MPa.

[0041] Embodiment 2:

[0042] The present embodiment provides a method for manufacturing an aluminum alloy flat ingot, the method comprising the following steps:

[0043] 1. According to the mass percentage of 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, high-purity aluminum ingots, metal Cu, metal Mg, metal Zn, AlTi6 master alloy, AlZr3 master alloy and AlSc3 master alloy are weighed as smelting raw materials;

[0044] 2. Add the smelting raw materials weighed in step 1 to high-purity aluminum ingots in order, then add metal Cu, metal Zn, AlZr3 master alloy and AlSc3 master alloy, and then add metal Mg and AlTi6 master alloy into a natural gas melting furnace to melt into a melt. The smelting temperature is controlled at 750-820° C. during the feeding process; after the feeding is completed, the melt temperature is maintained at 810° C., and stirred once every 20 minutes, for a total of 2 times; use a coated tool to take samples, the melt temperature is 775° C. during sampling, analyze the chemical composition, and after the chemical composition is qualified, cover it with flux to obtain an alloy melt;

[0045] 3. The alloy melt obtained in step 2 is introduced into a static furnace at a temperature of 760°C, and an argon-chlorine mixed gas is introduced for refining for 30 minutes, and then the alloy melt refined in the static furnace is first flowed into an online degassing device, and then into a filtering device, and then injected into a crystallizer through a flow disk under the condition of online seeding of AlTi5B1A wire for semi-continuous casting. The casting speed is controlled to be 46 mm / min, the casting temperature is 725°C, and the casting cooling water pressure is 0.025 MPa to obtain the aluminum alloy flat ingot, thereby completing the preparation.

[0046] The flux used in step 2 is composed of 40% KCl, 45% MgCl2, 8% BaCl2 and 7% NaCl+CaCl2 by mass percentage, and the added amount is 5kg / ton of melt.

[0047] Step 3: introducing an argon-chlorine mixed gas having a volume content of 95% argon and 5% chlorine.

[0048] Step 3: The rate of introducing argon-chlorine mixed gas is 0.06-0.018 m / s. 3 / h.

[0049] Step 3: The precision of the ceramic sheet flowing into the filtration device is 30ppi+50ppi.

[0050] Step 3: Online seeding of AlTi5B1A wire in which the mass content of Ti is 5%, the mass content of B is 1%, and the balance is Al. The seeding speed is controlled to 370 mm / min.

[0051] The aluminum alloy flat ingot obtained in this embodiment has qualified chemical composition, qualified flaw detection, no oxide film, no surface defects such as cracks and slag inclusions, and the strength is increased by 43MPa.

[0052] Embodiment three:

[0053] The present embodiment provides a method for manufacturing an aluminum alloy flat ingot, the method comprising the following steps:

[0054] 1. According to the mass percentage of elements: 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 ingots, metal Cu, metal Mg, metal Zn, AlTi6 master alloy, AlZr3 master alloy and AlSc3 master alloy are weighed as smelting raw materials;

[0055] 2. Add the smelting raw materials weighed in step 1 to high-purity aluminum ingots in order, then add metal Cu, metal Zn, AlZr3 master alloy and AlSc3 master alloy, and then add metal Mg and AlTi6 master alloy into a natural gas melting furnace to melt into a melt. During the feeding process, the smelting temperature is controlled to be 750-820°C; after the feeding is completed, the melt temperature is maintained at 815°C, and stirred once every 20 minutes, for a total of 2 times; use a coated tool to take samples, the melt temperature is 800°C during sampling, and the chemical composition is analyzed. After the chemical composition is qualified, it is covered with flux to obtain an alloy melt;

[0056] 3. The alloy melt obtained in step 2 is introduced into a static furnace at a temperature of 770°C, and an argon-chlorine mixed gas is introduced for refining for 30 minutes, and then the alloy melt refined in the static furnace is first flowed into an online degassing device, and then into a filtering device, and then injected into a crystallizer through a flow disk 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, thereby completing the preparation.

[0057] The flux used in step 2 is composed of 40% KCl, 45% MgCl2, 8% BaCl2 and 7% NaCl+CaCl2 by mass percentage, and the added amount is 5kg / ton of melt.

[0058] Step 3: introducing an argon-chlorine mixed gas having a volume content of 95% argon and 5% chlorine.

[0059] Step 3: The rate of introducing argon-chlorine mixed gas is 0.06-0.018 m / s. 3 / h.

[0060] Step 3: The precision of the ceramic sheet flowing into the filtration device is 30ppi+50ppi.

[0061] Step 3: Online seeding of AlTi5B1A wire in which the mass content of Ti is 5%, the mass content of B is 1%, and the balance is Al. The seeding speed is controlled to 370 mm / min.

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

[0063] The above content cannot be used to determine that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, they can make several simple deductions or substitutions without departing from the concept of the present invention, which should be regarded as belonging to the scope of patent protection of the present invention determined by the submitted claims.

Claims

1. A method for manufacturing an aluminum alloy flat ingot, characterized in that The method comprises the following steps:

1. Ingredients: 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, weigh high-purity aluminum ingots, metal Cu, metal Mg, metal Zn, AlTi6 master alloy, AlZr3 master alloy and AlSc3 master alloy as smelting raw materials; 2. Melting: first add the smelting raw materials weighed in step 1 to high-purity aluminum ingots in order, then add metal Cu, metal Zn, AlZr3 master alloy and AlSc3 master alloy, and then add metal Mg and AlTi6 master alloy into a natural gas melting furnace to melt into a melt. During the feeding process, the melting temperature is controlled to be 750-820°C; after the feeding is completed, the melt temperature is maintained at 800°C, and stirred once every 20 minutes, for a total of 2 times; use a coated tool to take samples, the melt temperature is ≥750°C during sampling, analyze the chemical composition, and after the chemical composition is qualified, cover it with flux to obtain an alloy melt; 3. Casting: The alloy melt obtained in step 2 is introduced into a static furnace at a temperature of 740-780°C, and argon-chlorine mixed gas is introduced for refining for 30 minutes, and then the alloy melt refined in the static furnace is first flowed into an online degassing device, and then into a filtering device, and then injected into a crystallizer through a flow disk under the condition of online seeding of AlTi5B1A wire, and semi-continuous casting is performed, the casting speed is controlled to be 42mm / min-48mm / min, the casting temperature is 710-740°C, and the casting cooling water pressure is 0.01-0.05MPa, to obtain the aluminum alloy flat ingot, and the preparation is completed.

2. The method for manufacturing an aluminum alloy flat ingot according to claim 1, characterized in that Step 1 The mass purity of the high-purity aluminum ingot is 99.99%.

3. The method for manufacturing an aluminum alloy flat ingot according to claim 1, characterized in that The AlZr3 master alloy in step 1 has a Zr content of 3% by mass and the rest is Al; The mass content of Sc in the AlSc3 master alloy is 3%, and the rest is Al.

4. The method for manufacturing an aluminum alloy flat ingot according to claim 1, characterized in that When the AlSc3 master alloy is added in step 2, the melt temperature is above 800°C.

5. The method for manufacturing an aluminum alloy flat ingot according to claim 1, characterized in that The flux used in step 2 is composed of 40% KCl, 45% MgCl2, 8% BaCl2 and 7% NaCl+CaCl2 in terms of mass percentage, and the amount of solvent added is 5kg / ton of melt.

6. The method for manufacturing an aluminum alloy flat ingot according to claim 1, characterized in that Step 3: introducing an argon-chlorine mixed gas having a volume content of 95% argon and 5% chlorine; The rate of introducing argon-chlorine mixed gas is 0.06~0.018m 3 / h.

7. The method for manufacturing an aluminum alloy flat ingot according to claim 1, characterized in that Step 3: The shape of the melt injected into the crystallizer is a rectangle of 420 mm × 1620 mm.

8. The method for manufacturing an aluminum alloy flat ingot according to claim 1, characterized in that Step 3: The precision of the ceramic sheet flowing into the filtration device is 30ppi+50ppi.

9. The method for manufacturing an aluminum alloy flat ingot according to claim 1, characterized in that Step 3: Online seeding of AlTi5B1A wire in which the mass content of Ti is 5%, the mass content of B is 1%, and the balance is Al. The seeding speed is controlled to 370 mm / min.

10. The method for manufacturing an aluminum alloy flat ingot according to claim 1, characterized in that The size of the aluminum alloy flat ingot obtained by the semi-continuous casting in step three is 420mm×1620mm×(3000mm~6000mm).