Al-mg-zn series aluminum alloy flat ingot containing er element and manufacturing method thereof

Abstract

The application relates to an Al-Mg-Zn series aluminum alloy flat ingot containing an Er element and a manufacturing method thereof, and aims to improve the corrosion resistance of the existing Al-Mg-Zn series aluminum alloy. The alloy is composed of Mn, Mg, Zn, Ti, Zr, Er and the balance of Al. The manufacturing method comprises the following steps: batching and smelting, smelting pure aluminum ingots, metal Zn, metal Mg, Al-Mn intermediate alloy, Al-Ti intermediate alloy and Al-Zr intermediate alloy, adding Al-Er intermediate alloy at 780 DEG C or above, stirring after heat preservation at 780 DEG C or above for 20 min, a total of 2 times of heat preservation and 2 times of stirring, heating to 780 DEG C-800 DEG C to obtain a melt, refining and finally casting. The application improves the heat stability and corrosion resistance of the alloy, and enhances the tensile strength and hardness. The application is applied to the field of aluminum alloys.

Description

TECHNICAL FIELD

[0001] The present application relates to an Er-containing Al-Mg-Zn series aluminum alloy flat ingot and a manufacturing method thereof. BACKGROUND

[0002] Aluminum magnesium zinc alloy (Al-Mg-Zn) is an important light high-strength alloy, which is widely used in the fields of aviation, aerospace, automobile, electronics, etc. With the continuous improvement of the performance requirements of modern industry on materials, the research and application of aluminum magnesium zinc alloy has become a hot spot in the field of material science. Historically, the research of aluminum magnesium zinc alloy can be traced back to the early 20th century, when the research mainly focused on the phase diagram and related system of the alloy. With the continuous improvement of the performance requirements of the final product, the continuous emergence of new products, and the continuous improvement of the basic performance requirements of the raw materials, the existing Al-Mg-Zn series aluminum alloy has high strength, but poor corrosion resistance. SUMMARY

[0003] The purpose of the present application is to improve the corrosion resistance of the existing Al-Mg-Zn series aluminum alloy, and to provide an Er-containing Al-Mg-Zn series aluminum alloy flat ingot and a manufacturing method thereof.

[0004] The Er-containing Al-Mg-Zn series aluminum alloy flat ingot according to the present application is composed of Mn: 0.30-0.60%, Mg: 1.70%-2.20%, Zn: 5.3%-6.3%, Ti: 0.01-0.05%, Zr: 0.09-0.13%, Er: 0.10-0.25%, Si<0.08%, Fe<0.12%, Cu<0.1%, and the balance of Al, in terms of mass percentage.

[0005] The manufacturing method of the Er-containing Al-Mg-Zn series aluminum alloy flat ingot according to the present application is as follows:

[0006] I. batching: according to the mass percentage of each element: Mn: 0.30-0.60%, Mg: 1.70%-2.20%, Zn: 5.3%-6.3%, Ti: 0.01-0.05%, Zr: 0.09-0.13%, Er: 0.10-0.25%, and the balance of Al, pure aluminum ingot, metal Zn, metal Mg, Al-Mn intermediate alloy, Al-Ti intermediate alloy, Al-Zr intermediate alloy, and Al-Er intermediate alloy are weighed according to the ratio;

[0007] II. melting:

[0008] The raw materials weighed in step one are added in the order of pure aluminum ingot, Al-Mn intermediate alloy, Al-Zr intermediate alloy, and when the temperature of the melt is 680℃, metal Zn is added, and then when the temperature of the melt is raised to 720-740℃, metal Mg and Al-Ti intermediate alloy are added; when the temperature of the melt is greater than 780℃, Al-Er intermediate alloy is added, and then when the temperature of the melt is raised to >780℃, the melt is kept at this temperature, and then stirred, and then the temperature of the melt is raised to >780℃, and kept at this temperature, and then stirred, and then the temperature of the melt is raised to 780-800℃;

[0009] III. Casting:

[0010] At a temperature of 720-750℃, the melt obtained in step two is refined, allowed to stand, and then a flat ingot with a thickness of 420mm, a width of 1620mm, and a length of 5000-6000mm is obtained at a casting speed of 45-55mm / min, a casting temperature of 710-730℃, and a casting cooling water flow rate of 40-60m 3 / h. 3 / h.

[0011] The addition of trace amounts of Er element in the Al-Mg-Zn aluminum alloy can significantly refine the as-cast grains, inhibit recrystallization, thereby improving the thermal stability and intergranular corrosion resistance of the alloy, and enhancing the tensile strength and hardness. Meanwhile, the Er element can synergize with the Zr element to further improve the comprehensive performance of the aluminum alloy. In combination with production practice, the flat ingot of the Al-Mg-Zn aluminum alloy containing Er element and the manufacturing method thereof are formed.

[0012] The beneficial effects of the present application are as follows:

[0013] Compared with the general Al-Mg-Zn alloy, the flat ingot of the Al-Mg-Zn aluminum alloy containing Er element of the present application has trace amounts of Er element added, and the Zr element synergizes with the Er element, the grain refinement and recrystallization inhibition effects are significant, the grain size of the ingot can reach 1.5-2 levels, the thermal stability and corrosion resistance of the alloy are improved, and the tensile strength and hardness are enhanced. DETAILED DESCRIPTION

[0014] The technical solutions of the present application are not limited to the specific embodiments listed below, and also include any combination of the specific embodiments.

[0015] Specific embodiment one: the Al-Mg-Zn aluminum alloy flat ingot containing Er element is composed of Mn: 0.30-0.60%, Mg: 1.70%-2.20%, Zn: 5.3%-6.3%, Ti: 0.01-0.05%, Zr: 0.09-0.13%, Er: 0.10-0.25%, Si <0.08%, Fe <0.12%, Cu <0.1% and the balance of Al by mass percent.

[0016] Specific embodiment two: different from the specific embodiment one, the aluminum alloy flat ingot is composed of Mn: 0.50%, Mg: 2.0%, Zn: 5.80%, Ti: 0.025%, Zr: 0.12%, Er: 0.20%, Si <0.08%, Fe <0.12%, Cu <0.1% and the balance of Al by mass percent. The others are the same as the specific embodiment one.

[0017] Specific embodiment three: the manufacturing method of the Al-Mg-Zn aluminum alloy flat ingot containing Er element is as follows:

[0018] I. batching: the pure aluminum ingot, metal Zn, metal Mg, Al-Mn intermediate alloy, Al-Ti intermediate alloy, Al-Zr intermediate alloy and Al-Er intermediate alloy are weighed according to the mass percentage of each element: Mn: 0.30-0.60%, Mg: 1.70%-2.20%, Zn: 5.3%-6.3%, Ti: 0.01-0.05%, Zr: 0.09-0.13%, Er: 0.10-0.25% and the balance of Al;

[0019] II. melting:

[0020] the raw materials weighed in step I are added in the following order: the pure aluminum ingot, Al-Mn intermediate alloy, Al-Zr intermediate alloy, the metal Zn is added when the melt temperature is 680℃, the metal Mg and Al-Ti intermediate alloy are added when the melt temperature is increased to 720-740℃, the Al-Er intermediate alloy is added when the melt temperature is greater than 780℃, then the melt temperature is increased to >780℃ for holding, then stirring, then the melt temperature is increased to >780℃ for holding, then stirring, and then the melt temperature is increased to 780-800℃;

[0021] III. casting:

[0022] the melt obtained in step II is refined at a temperature of 720-750℃, then placed, then cast at a casting speed of 45-55mm / min, a casting temperature of 710-730℃ and a casting cooling water flow of 40-60m 3 / h. 3The alloy ingot with thickness of 420 mm, width of 1620 mm and length of 5000-6000 mm is obtained under the condition of 1.5 m / h.

[0023] The stirring in step two of the embodiment causes the temperature of the melt to decrease, and therefore the temperature needs to be increased to above 780°C again.

[0024] Specific embodiment four: different from the specific embodiment three, in step one, the elements are weighed according to the following mass percentage: Mn: 0.50%, Mg: 2.0%, Zn: 5.80%, Ti: 0.025%, Zr: 0.12%, Er: 0.20%, and the balance of Al. The other steps are the same as those in the specific embodiment three.

[0025] Specific embodiment five: different from the specific embodiment three or four, in step two, the melt is heated to 730°C, and then the metal Mg and Al-Ti intermediate alloy are added. The other steps are the same as those in the specific embodiment three or four.

[0026] Specific embodiment six: different from one of the specific embodiments three to five, in step two, the temperature is kept for 20 min. The other steps are the same as those in one of the specific embodiments three to five.

[0027] Specific embodiment seven: different from one of the specific embodiments three to six, in step three, the refining is performed for 30 min using argon-chlorine mixed gas. The argon-chlorine mixed gas is mixed by 96% argon and 4% chlorine according to the molar volume. The other steps are the same as those in one of the specific embodiments three to six.

[0028] Specific embodiment eight: different from one of the specific embodiments three to seven, in step three, the melt is kept for 30 min. The other steps are the same as those in one of the specific embodiments three to seven.

[0029] Specific embodiment nine: different from one of the specific embodiments two to eight, in step three, the casting speed is 50 mm / min. The other steps are the same as those in one of the specific embodiments two to eight.

[0030] Specific embodiment ten: different from one of the specific embodiments two to nine, in step three, the casting temperature is 716°C, and the cooling water is 45 m 3 / h. The other steps are the same as those in one of the specific embodiments two to nine.

[0031] The beneficial effects of the present application are verified by the following examples:

[0032] Example one: the manufacturing method of the Al-Mg-Zn series aluminum alloy flat ingot containing Er element, which is performed according to the following steps:

[0033] I. Ingredients: according to the mass percentage of each element: Mn: 0.50%, Mg: 2.0%, Zn: 5.80%, Ti: 0.025%, Zr: 0.12%, Er: 0.20%, the balance being Al. Weighing pure aluminum ingot, metal Zn, metal Mg, Al-Mn intermediate alloy, Al-Ti intermediate alloy, Al-Zr intermediate alloy and Al-Er intermediate alloy;

[0034] II. Melting:

[0035] A. The raw materials weighed in step I are added in the order of pure aluminum ingot, Al-Mn intermediate alloy, Al-Zr intermediate alloy, and when the melt temperature is 680°C, metal Zn is added;

[0036] B. When the melt temperature is 725°C, metal Mg and Al-Ti intermediate alloy are added;

[0037] C. When the melt temperature is 782°C, Al-Er intermediate alloy is added;

[0038] D. After the melt temperature reaches 785°C, heat preservation for 20 min, stirring once;

[0039] E. After the melt temperature reaches 783°C, heat preservation for 20 min, stirring again;

[0040] F. The melt temperature is raised to 796°C to obtain an aluminum alloy melt.

[0041] III. Casting

[0042] The melt obtained in step II is passed through argon-chlorine gas refining at a temperature of 728°C for 30 min, and then placed for 30 min, and then cast at a casting speed of 50 mm / min, a casting temperature of 716°C, and a casting cooling water of 45 m 3 / h to obtain an alloy ingot with a thickness of 420 mm, a width of 1620 mm, and a length of 5820 mm.

[0043] Compared with the general Al-Mg-Zn alloy, the Er element-containing Al-Mg-Zn aluminum alloy flat ingot of the present embodiment has a trace amount of Er element added, and cooperates with Zr element, so that the grain refinement and recrystallization inhibition effect are remarkable, the ingot grain size can reach 1.5-2 grade, thereby improving the thermal stability and corrosion resistance of the alloy, and enhancing the tensile strength and hardness.

Claims

1. An Er element-containing Al-Mg-Zn system aluminum alloy slab, characterized by comprising, in mass %, The aluminum alloy flat ingot is composed of Mn: 0.50%, Mg: 2.0%, Zn: 5.80%, Ti: 0.025%, Zr: 0.12%, Er: 0.20%, Si < 0.08%, Fe < 0.12%, Cu < 0.1% and the balance of Al in terms of mass percentage; The manufacturing method of the Er-containing Al-Mg-Zn aluminum alloy flat ingot is as follows: I. Ingredients: pure aluminum ingot, metal Zn, metal Mg, Al-Mn intermediate alloy, Al-Ti intermediate alloy, Al-Zr intermediate alloy and Al-Er intermediate alloy are weighed according to the mass percentage of each element; II. Melting: The raw materials weighed in step I are added in the following order: pure aluminum ingot, Al-Mn intermediate alloy, Al-Zr intermediate alloy, metal Zn when the melt temperature is 680℃, metal Mg and Al-Ti intermediate alloy when the melt temperature is raised to 720-740℃, Al-Er intermediate alloy when the melt temperature is greater than 780℃, and then the melt temperature is raised to >780℃ for holding, followed by stirring, and then the melt temperature is raised to >780℃ for holding, followed by stirring, and then the melt temperature is raised to 780-800℃. III. Casting: The melt obtained in Step 2 was refined at a temperature of 720 to 750°C, allowed to stand, and then cast at a casting speed of 45 to 55 mm / min, a casting temperature of 710 to 730°C, and a casting cooling water of 40 to 60 m 3 / h to obtain an alloy ingot having a thickness of 420 mm, a width of 1620 mm, and a length of 5000 to 6000 mm. 3 / h to obtain an alloy ingot having a thickness of 420 mm, a width of 1620 mm, and a length of 5000 to 6000 mm.

2. The Er-containing Al-Mg-Zn series aluminum alloy flat ingot according to claim 1, characterized in that, The melt temperature is raised to 730℃ in step II, and metal Mg and Al-Ti intermediate alloy are added.

3. The Er-containing Al-Mg-Zn series aluminum alloy flat ingot according to claim 1, characterized in that, The holding time in step II is 20 min.

4. The Er-containing Al-Mg-Zn series aluminum alloy flat ingot according to claim 1, characterized in that, In step III, argon-chlorine mixed gas is used for 30 minutes of refining, and the argon-chlorine mixed gas is composed of 96% argon and 4% chlorine by mole volume.

5. The Er-containing Al-Mg-Zn series aluminum alloy flat ingot according to claim 1, characterized in that, In step III, the melt is left to stand for 30 min.

6. The Er-containing Al-Mg-Zn series aluminum alloy flat ingot according to claim 1, characterized in that, The casting speed in step III is 50 mm / min.

7. The Er-containing Al-Mg-Zn series aluminum alloy flat ingot according to claim 1, characterized in that, Step three casting temperature 716°C, casting cooling water 45 m 3 / h.