A marine corrosion-resistant plate aluminum alloy flat ingot and a manufacturing method thereof

Abstract

The application discloses an aluminum alloy flat ingot for ship corrosion-resistant plate and a manufacturing method thereof, and belongs to the field of alloy ingot manufacturing. The application solves the problem of low yield of the ingot caused by cracks in the casting process or the subsequent rolling process of the existing aluminum alloy flat ingot. The material is composed of Si, Fe, Mg, Mn, Zr, Er, Zn, Cu, Ti, impurities and the balance of Al. The method comprises the following steps: 1, weighing the smelting raw material; 2, smelting the raw material in sequence; and 3, placing the alloy melt into a natural gas holding furnace to obtain the aluminum alloy flat ingot. The application adopts the existing magnesium cage and pure magnesium ingot, reduces the burning loss of the magnesium ingot and the local temperature drop of the metal melt, adds aluminum-zirconium intermediate alloy to increase the crust thickness of the ingot, reduces the formation of vertical folds on the surface of the ingot, reduces the crack tendency of the ingot, and combines the adjustment of the casting process parameters and the fine operation in the production process, so that the yield of the aluminum alloy flat ingot reaches 80%.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of alloy ingot manufacturing, in particular to a kind of marine corrosion-resistant plate aluminum alloy flat ingot and manufacturing method thereof. BACKGROUND

[0002] Marine aluminum alloy can be divided into deformation aluminum alloy and casting aluminum alloy according to different manufacturing processes, and corrosion resistance is an important use performance of marine aluminum alloy, and the corrosion resistance of alloy directly affects the reliability and service life of ship. Since marine aluminum alloy has special requirements on strength, corrosion resistance, weldability and the like, therefore, marine aluminum alloy is mostly selected from aluminum-magnesium alloy, aluminum-magnesium-silicon alloy and aluminum-zinc-magnesium alloy. It has the characteristics of low density, high tensile strength, strong resistance to seawater and marine climate corrosion, and good welding performance. SUMMARY

[0003] The purpose of the present application is to solve the problem that the existing aluminum alloy flat ingot is prone to cracks during casting process or in subsequent rolling process, thereby resulting in low yield of ingot product, and to provide a kind of marine corrosion-resistant plate aluminum alloy flat ingot and manufacturing method thereof.

[0004] A kind of marine corrosion-resistant plate aluminum alloy flat ingot, which comprises Si<0.25%, Fe<0.25%, Mg: 5.30%~6.30%, Mn: 0.40%~1.00%, Zr: 0.05%~0.15%, Er: 0.10%~0.30%, Zn: 0.30%~0.90%, Cu<0.1%, Ti<0.25%, single impurity<0.05%, total impurities≤0.15%, and the balance is Al.

[0005] The manufacturing method of the above-mentioned marine corrosion-resistant plate aluminum alloy flat ingot is carried out by the following steps:

[0006] I. Weighing: according to the weight percentage composition of Si<0.25%, Fe<0.25%, Mg: 5.30%~6.30%, Mn: 0.40%~1.00%, Zr: 0.05%~0.15%, Er: 0.10%~0.30%, Zn: 0.30%~0.90%, Cu<0.1%, Ti<0.25%, single impurity<0.05%, total impurities≤0.15%, and the balance is Al; pure aluminum ingot, metal Zn, pure magnesium ingot, aluminum-manganese intermediate alloy, aluminum-zirconium intermediate alloy and aluminum-erbium intermediate alloy are weighed as smelting raw materials;

[0007] II. Melting: the weighed pure aluminum ingot, aluminum manganese intermediate alloy and aluminum zirconium intermediate alloy are added into a melting furnace, the melting temperature is 750-800℃, when the temperature of the melt reaches above 750℃, the metal Zn is added, and stirred once, when the temperature of the melt reaches above 780℃, the aluminum erbium intermediate alloy is added, and stirred once after 20 minutes of holding, when the temperature of the melt reaches above 780℃, the melt is stirred once again after 20 minutes of holding, then the melt is cooled, when the temperature of the melt drops to 750℃, the pure magnesium ingot is added using a magnesium cage, and after stirring, the No. 2 covering agent is added to obtain an aluminum alloy melt;

[0008] III. The above-mentioned aluminum alloy melt is introduced into a natural gas holding furnace at 770-780℃, argon-chlorine mixed gas is introduced for 30 minutes, and then the melt is held for 30 minutes, then the semi-continuous casting is carried out under the conditions that the casting speed is 45-55 mm / min, the casting temperature is 750-770℃, the casting cooling water flow is 35-45 m 3 / h, and the crystallizer metal liquid level is 80-90 mm, to obtain an aluminum alloy flat ingot with a thickness of 420 mm, a width of 1620 mm, and a length of 5500-6500 mm, i.e. the manufacturing is completed.

[0009] Further, the purity of the pure aluminum ingot in step one is 99.7%.

[0010] Further, the amount of the No. 2 covering agent in step two is 0.4-0.6% of the total mass of the metal in the melting furnace.

[0011] Further, the No. 2 covering agent in step two is composed of 45% KCl, 30% NaCl and 25% Na3AlF6 by mass percentage.

[0012] Further, the introduction rate of the argon-chlorine mixed gas in step two is 0.15-0.20 m 3 / min.

[0013] Further, the volume ratio of argon and chlorine in the argon-chlorine mixed gas in step two is 1:1.

[0014] Advantages of the present application:

[0015] The present application uses the existing magnesium cage and pure magnesium ingot, reduces the burning loss of the magnesium ingot and the local temperature drop of the metal melt, adds the aluminum zirconium intermediate alloy to increase the shell thickness of the ingot, reduces the formation of vertical folds on the surface of the ingot, and reduces the tendency of cracks in the ingot, in combination with the adjustment of the casting process parameters and the fine operation in the production process, so that the yield of the aluminum alloy flat ingot reaches 80%.

[0016] The aluminum alloy flat ingot prepared by the present application has the thickness of 420mm, the width of 1620mm, and the length of 5500mm-6500mm, and has no cracks, slag inclusion, coarse grains and other defects on the surface, and has high ingot yield, and is suitable for ship and boat corrosion-resistant plate.

[0017] The present application is suitable for manufacturing the aluminum alloy flat ingot for ship and boat corrosion-resistant plate. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is the physical drawing of the aluminum alloy flat ingot in Example 4. DETAILED DESCRIPTION

[0019] The technical scheme of the present application is not limited to the following specific embodiments, and also includes any combination of the specific embodiments.

[0020] Specific embodiment one: the aluminum alloy flat ingot for ship and boat corrosion-resistant plate according to the present embodiment has the following composition by weight percentage: Si<0.25%, Fe<0.25%, Mg: 5.30%-6.30%, Mn: 0.40%-1.00%, Zr: 0.05%-0.15%, Er: 0.10%-0.30%, Zn: 0.30%-0.90%, Cu<0.1%, Ti<0.25%, single impurity<0.05%, total impurities≤0.15%, and the balance is Al.

[0021] Specific embodiment two: the aluminum alloy flat ingot for ship and boat corrosion-resistant plate according to the present embodiment has the following composition by weight percentage: Si<0.25%, Fe<0.25%, Mg: 6.0%, Mn: 0.70%, Zr: 0.11%, Er: 0.18%, Zn: 0.80%, Cu<0.1%, Ti<0.25%, single impurity<0.05%, total impurities≤0.15%, and the balance is Al. The other aspects are the same as those of specific embodiment one.

[0022] Specific embodiment three: the manufacturing method of the aluminum alloy flat ingot for ship and boat corrosion-resistant plate according to the present embodiment is carried out by the following steps:

[0023] I. weighing: the aluminum alloy flat ingot has the following composition by weight percentage: Si<0.25%, Fe<0.25%, Mg: 5.30%-6.30%, Mn: 0.40%-1.00%, Zr: 0.05%-0.15%, Er: 0.10%-0.30%, Zn: 0.30%-0.90%, Cu<0.1%, Ti<0.25%, single impurity<0.05%, total impurities≤0.15%, and the balance is Al; pure aluminum ingot, metal Zn, pure magnesium ingot, aluminum-manganese intermediate alloy, aluminum-zirconium intermediate alloy and aluminum-erbium intermediate alloy are weighed as smelting raw materials;

[0024] II. Melting: Put the weighed pure aluminum ingot, aluminum manganese intermediate alloy and aluminum zirconium intermediate alloy into the melting furnace, the melting temperature is 750-800℃, when the temperature of the melt reaches 750℃ or above, add the metal Zn, stir once, when the temperature of the melt reaches 780℃ or above, add the aluminum erbium intermediate alloy, after 20 minutes of holding, stir once, when the temperature of the melt reaches 780℃, after 20 minutes of holding, stir once again, then cool the melt, when the temperature of the melt drops to 750℃, add the pure magnesium ingot using the magnesium cage, after stirring, add the No. 2 covering agent to obtain the aluminum alloy melt;

[0025] III. Introduce the above-mentioned aluminum alloy melt into the natural gas holding furnace at 770-780℃, pass the argon-chlorine mixed gas for 30 minutes, then stand for 30 minutes, then perform semi-continuous casting under the conditions of casting speed of 45-55 mm / min, casting temperature of 750-770℃, casting cooling water flow of 35-45 m 3 / h, crystallizer metal liquid level of 80-90 mm to obtain the aluminum alloy flat ingot with thickness of 420 mm, width of 1620 mm and length of 5500-6500 mm, i.e. the manufacturing is completed.

[0026] Specific embodiment four: The difference between this embodiment and the specific embodiment three is that the purity of the pure aluminum ingot in step one is 99.7%. The other steps and parameters are the same as those in the specific embodiment three.

[0027] Specific embodiment five: The difference between this embodiment and the specific embodiment three is that the amount of the No. 2 covering agent in step two is 0.4%-0.6% of the total mass of the metal in the melting furnace. The other steps and parameters are the same as those in the specific embodiment three.

[0028] Specific embodiment six: The difference between this embodiment and the specific embodiment three is that the No. 2 covering agent in step two is composed of 45% KCl, 30% NaCl and 25% Na3AlF6 by mass percentage. The other steps and parameters are the same as those in the specific embodiment three.

[0029] Specific embodiment seven: The difference between this embodiment and the specific embodiment three is that the passing rate of the argon-chlorine mixed gas in step two is 0.15-0.20 m 3 / min. The other steps and parameters are the same as those in the specific embodiment three.

[0030] Specific embodiment eight: The difference between this embodiment and the specific embodiment three is that the volume ratio of argon to chlorine in the argon-chlorine mixed gas in step two is 1:1. The other steps and parameters are the same as those in the specific embodiment three.

[0031] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method Three in that, in step three, the casting speed is 48 mm / min, the casting temperature is 750–770℃, and the casting cooling water flow rate is 45 m³ / min. 3 Semi-continuous casting is carried out under the condition that the molten metal level in the crystallizer is 85 mm / h. Other steps and parameters are the same as in specific implementation method three.

[0032] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Three in that, in step three, the recasting speed is 50 mm / min, the casting temperature is 750–770℃, and the casting cooling water flow rate is 45 m³ / min. 3 Semi-continuous casting is performed at a temperature of 90 mm / h in the crystallizer. Other steps and parameters are the same as in Specific Implementation Method Three.

[0033] The beneficial effects of the present invention are verified through the following embodiments:

[0034] Example 1:

[0035] A method for manufacturing aluminum alloy flat ingots for corrosion-resistant steel plates for boats, comprising the following steps:

[0036] I. Weighing: The raw materials are composed of the following weight percentages: Si < 0.25%, Fe < 0.25%, Mg: 5.5%, Mn: 0.6%, Zr: 0.10%, Er: 0.20%, Zn: 0.40%, Cu < 0.1%, Ti < 0.25%, individual impurities < 0.05%, total impurities ≤ 0.15%, and the balance is Al; pure aluminum ingots, metallic Zn, pure magnesium ingots, aluminum-manganese master alloy, aluminum-zirconium master alloy, and aluminum-erbium master alloy are weighed as smelting raw materials;

[0037] II. Melting: Weigh out pure aluminum ingots, aluminum-manganese master alloy, and aluminum-zirconium master alloy and add them to the melting furnace. Melt at 750-800℃. When the melt temperature reaches above 750℃, add metallic Zn and stir once. When the melt temperature reaches above 780℃, add aluminum-erbium master alloy and hold for 20 minutes, then stir once. When the melt temperature rises to 780℃, hold for 20 minutes and stir again. When the melt temperature rises to 780℃, hold for 20 minutes and stir once more. Then cool the melt. When the melt temperature drops to 750℃, add pure magnesium ingots using a magnesium cage, stir, and then add No. 2 covering agent to obtain aluminum alloy melt.

[0038] 3. The above-mentioned aluminum alloy melt is introduced into a natural gas holding furnace at 770-780℃, refined by argon-chlorine mixed gas for 30 minutes, and then allowed to stand for 30 minutes. Then, the casting speed is 45-55 mm / min, the casting temperature is 750-770℃, and the casting cooling water flow rate is 40 m³ / min. 3The aluminum alloy flat ingot is obtained by semi-continuous casting under the condition that the h is 80 mm and the crystallizer metal liquid level is 80 mm, and the aluminum alloy flat ingot has a thickness of 420 mm, a width of 1620 mm and a length of 5500 mm, i.e. the manufacturing is completed.

[0039] The purity of the pure aluminum ingot in step one of the embodiment is 99.7%.

[0040] The amount of the No. 2 covering agent in step two of the embodiment is 0.5% of the total mass of the metal in the smelting furnace.

[0041] The No. 2 covering agent in step two of the embodiment is composed of 45% of KCl, 30% of NaCl and 25% of Na3AlF6 by mass percentage.

[0042] The feeding rate of the argon-chlorine mixed gas in step two of the embodiment is 0.20 m 3 / min.

[0043] The volume ratio of argon and chlorine in the argon-chlorine mixed gas in step two of the embodiment is 1:1.

[0044] The aluminum alloy flat ingot in the embodiment has no cracks, slag inclusions, coarse grains and other defects on the surface, and the yield rate reaches 67%, which is suitable for the manufacturing of ship and boat corrosion-resistant plates.

[0045] Embodiment 2:

[0046] A manufacturing method of a ship and boat corrosion-resistant plate aluminum alloy flat ingot, which is performed according to the following steps:

[0047] I. Weighing: the raw materials for smelting are pure aluminum ingot, metal Zn, pure magnesium ingot, aluminum-manganese intermediate alloy, aluminum-zirconium intermediate alloy and aluminum-erbium intermediate alloy, and the composition is as follows by weight percentage: Si <0.25%, Fe <0.25%, Mg: 5.80%, Mn: 0.70%, Zr: 0.12%, Er: 0.20%, Zn: 0.60%, Cu <0.1%, Ti <0.25%, single impurity <0.05%, total impurities ≤0.15%, and the balance is Al;

[0048] II. Smelting: the weighed pure aluminum ingot, aluminum-manganese intermediate alloy and aluminum-zirconium intermediate alloy are added to a smelting furnace, the smelting temperature is 750-800℃, the metal Zn is added when the smelting temperature reaches above 750℃, and stirred once, the aluminum-erbium intermediate alloy is added when the smelting temperature reaches above 780℃, and stirred once after 20 min of holding, the smelting temperature is increased to 780℃, and stirred once after 20 min of holding, the smelting temperature is increased to 780℃, and stirred once after 20 min of holding, and then the smelting is cooled, the pure magnesium ingot is added using a magnesium cage when the smelting temperature is reduced to 750℃, and the No. 2 covering agent is added after stirring to obtain an aluminum alloy smelting;

[0049] III. The aluminum alloy melt is introduced into a natural gas holding furnace at 770-780°C, argon-chlorine mixed gas is introduced for 30 minutes, and then the melt is left for 30 minutes. Then, semi-continuous casting is carried out at a casting speed of 48 mm / min, a casting temperature of 750-770°C, a casting cooling water flow of 45 m 3 / h, and a crystallizer metal level of 85 mm to obtain an aluminum alloy flat ingot with a thickness of 420 mm, a width of 1620 mm, and a length of 5700 mm, i.e. the manufacturing is completed.

[0050] The purity of the pure aluminum ingot in Step I of this example is 99.7%.

[0051] The amount of the No. 2 covering agent used in Step II of this example is 0.5% of the total mass of the metal in the smelting furnace.

[0052] The No. 2 covering agent used in Step II of this example is composed of 45% KCl, 30% NaCl, and 25% Na3AlF6 by mass percentage.

[0053] The rate of introduction of the argon-chlorine mixed gas used in Step II of this example is 0.20 m 3 / min.

[0054] The volume ratio of argon to chlorine in the argon-chlorine mixed gas used in Step II of this example is 1:1.

[0055] The aluminum alloy flat ingot of this example has no cracks, slag inclusions, coarse grains, and other defects on the surface, and the yield rate reaches 75%, which is suitable for the manufacture of ship and boat corrosion-resistant plates.

[0056] Example 3:

[0057] A method for manufacturing an aluminum alloy flat ingot for ship and boat corrosion-resistant plates is carried out according to the following steps:

[0058] I. Weighing: pure aluminum ingot, metallic Zn, pure magnesium ingot, aluminum-manganese intermediate alloy, aluminum-zirconium intermediate alloy, and aluminum-erbium intermediate alloy are weighed as smelting raw materials according to the following weight percentage composition: Si < 0.25%, Fe < 0.25%, Mg: 6.30%, Mn: 0.8%, Zr: 0.13%, Er: 0.25%, Zn: 0.75%, Cu < 0.1%, Ti < 0.25%, individual impurities < 0.05%, total impurities ≤ 0.15%, and the balance being Al;

[0059] II. Melting: Put the weighed pure aluminum ingot, aluminum manganese intermediate alloy and aluminum zirconium intermediate alloy into a melting furnace, the melting temperature is 750-800°C, when the temperature of the melt reaches above 750°C, add metal Zn, stir once, when the temperature of the melt reaches above 780°C, add aluminum erbium intermediate alloy, after 20 minutes of holding, stir once, when the temperature of the melt reaches above 780°C, after 20 minutes of holding, stir once, then cool the melt, when the temperature of the melt drops to 750°C, add pure magnesium ingot using a magnesium cage, after stirring, add No. 2 covering agent to obtain an aluminum alloy melt;

[0060] III. Put the above aluminum alloy melt into a natural gas holding furnace at 770-780°C, pass argon-chlorine mixed gas for 30 minutes, then stand for 30 minutes, then perform semi-continuous casting at a casting speed of 52 mm / min, a casting temperature of 750-770°C, a casting cooling water flow of 45 m 3 / h, and a crystallizer metal liquid level of 90 mm to obtain an aluminum alloy flat ingot with a thickness of 420 mm, a width of 1620 mm, and a length of 6000 mm, i.e. the manufacturing is completed.

[0061] The purity of the pure aluminum ingot in step I of the example is 99.7%.

[0062] The amount of the No. 2 covering agent in step II of the example is 0.5% of the total mass of the metal in the melting furnace.

[0063] The No. 2 covering agent in step II of the example is composed of 45% KCl, 30% NaCl, and 25% Na3AlF6 by mass percentage.

[0064] The passing rate of the argon-chlorine mixed gas in step II of the example is 0.20 m 3 / min.

[0065] The volume ratio of argon to chlorine in the argon-chlorine mixed gas in step II of the example is 1:1.

[0066] The aluminum alloy flat ingot in the example has no cracks, slag inclusions, coarse grains, etc. on the surface, and the yield reaches 70%, which is suitable for the manufacture of ship and boat corrosion-resistant plates.

[0067] Example 4:

[0068] A manufacturing method of a ship and boat corrosion-resistant plate aluminum alloy flat ingot, which is performed according to the following steps:

[0069] I. Weighing: the composition by weight percentage is Si < 0.25%, Fe < 0.25%, Mg: 6.0%, Mn: 0.70%, Zr: 0.11%, Er: 0.18%, Zn: 0.80%, Cu < 0.1%, Ti < 0.25%, single impurity < 0.05%, total impurities ≤ 0.15%, and the balance is Al; pure aluminum ingot, metal Zn, pure magnesium ingot, aluminum manganese master alloy, aluminum zirconium master alloy and aluminum erbium master alloy are weighed as smelting raw materials;

[0070] II. Smelting: the weighed pure aluminum ingot, aluminum manganese master alloy and aluminum zirconium master alloy are added to the smelting furnace, the smelting temperature is 750-800℃, when the melt temperature reaches above 750℃, metal Zn is added, and stirred once, when the melt temperature reaches above 780℃, aluminum erbium master alloy is added, and stirred once after holding for 20 min, when the melt temperature rises to 780℃, holding for 20 min, and then stirring once again, then the melt is cooled, when the melt temperature drops to 750℃, pure magnesium ingot is added using a magnesium cage, and after stirring, No. 2 covering agent is added to obtain an aluminum alloy melt;

[0071] III. The above-mentioned aluminum alloy melt is introduced into a natural gas holding furnace at 770-780℃, argon-chlorine mixed gas is introduced for 30 min, and then static for 30 min, then semi-continuous casting is carried out under the conditions of casting speed 48 mm / min, casting temperature 750-770℃, casting cooling water flow rate 45 m 3 / h, crystallizer metal level 85 mm, to obtain an aluminum alloy flat ingot with thickness 420 mm, width 1620 mm and length 6500 mm, i.e. the manufacturing is completed.

[0072] The purity of the pure aluminum ingot in step I of the embodiment is 99.7%.

[0073] The amount of the No. 2 covering agent in step II of the embodiment is 0.5% of the total mass of the metal in the smelting furnace.

[0074] The No. 2 covering agent in step II of the embodiment is composed of 45% KCl, 30% NaCl and 25% Na3AlF6 by mass percentage.

[0075] The introduction rate of the argon-chlorine mixed gas in step II of the embodiment is 0.20 m 3 / min.

[0076] The volume ratio of argon to chlorine in the argon-chlorine mixed gas in step II of the embodiment is 1:1.

[0077] In the embodiment, the aluminum alloy flat ingot has no cracks, slag inclusions, coarse grains and other defects on the surface, and the yield reaches 80%, for example, Figure 1The shown aluminum alloy flat ingot is well formed and suitable for manufacturing corrosion-resistant plate for boats and ships.

Claims

1. A corrosion resistant plate for marine vessels, an aluminum alloy slab ingot, characterized by It is composed of Si < 0.25%, Fe < 0.25%, Mg: 5.30%~6.30%, Mn: 0.40~1.00%, Zr: 0.05%~0.15%, Er: 0.10%~0.30%, Zn: 0.30%~0.90%, Cu < 0.1%, Ti < 0.25%, single impurity < 0.05%, total impurities ≤ 0.15%, and the balance of Al by weight percentage; The boat corrosion-resistant plate aluminum alloy flat ingot is manufactured by the following steps: I. Weighing: pure aluminum ingot, metal Zn, pure magnesium ingot, aluminum manganese intermediate alloy, aluminum zirconium intermediate alloy and aluminum erbium intermediate alloy are weighed as smelting raw materials according to the above weight percentage composition of Si < 0.25%, Fe < 0.25%, Mg: 5.30%~6.30%, Mn: 0.40%~1.00%, Zr: 0.05%~0.15%, Er: 0.10%~0.30%, Zn: 0.30%~0.90%, Cu < 0.1%, Ti < 0.25%, single impurity < 0.05%, total impurities ≤ 0.15%, and the balance of Al; II. Smelting: the weighed pure aluminum ingot, aluminum manganese intermediate alloy and aluminum zirconium intermediate alloy are added to the smelting furnace, the smelting temperature is 750~800℃, when the melt temperature reaches 750℃ or above, the metal Zn is added, and stirred once, when the melt temperature reaches 780℃ or above, the aluminum erbium intermediate alloy is added, and stirred once after 20min of holding, when the melt temperature rises to 780℃, and stirred once after 20min of holding, when the melt temperature rises to 780℃, and stirred once after 20min of holding, then the melt is cooled, when the melt temperature drops to 750℃, the pure magnesium ingot is added using a magnesium cage, and then 2# covering agent is added after stirring to obtain an aluminum alloy melt; III. The aluminum alloy melt is introduced into a natural gas holding furnace at 770-780°C, argon-chlorine mixed gas is introduced for 30 minutes for refining, and then the melt is left for 30 minutes. Then, semi-continuous casting is performed at a casting speed of 45-55 mm / min, a casting temperature of 750-770°C, a casting cooling water flow rate of 35-45 m 3 / h, and a crystallizer metal level of 80-90 mm to obtain an aluminum alloy flat cast ingot with a thickness of 420 mm, a width of 1620 mm, and a length of 5500-6500 mm, thereby completing the manufacturing.

2. The marine corrosion-resistant plate aluminum alloy slab ingot according to claim 1, characterized in that It is composed of Si < 0.25%, Fe < 0.25%, Mg: 6.0%, Mn: 0.70%, Zr: 0.11%, Er: 0.18%, Zn: 0.80%, Cu < 0.1%, Ti < 0.25%, single impurity < 0.05%, total impurities ≤ 0.15%, and the balance of Al by weight percentage.

3. The marine corrosion resistant sheet aluminum alloy flat ingot of claim 1 wherein The purity of the pure aluminum ingot in step one is 99.7%.

4. The corrosion resistant plate for marine use according to claim 1, wherein The amount of the 2# covering agent in step two is 0.4%~0.6% of the total mass of the metal in the smelting furnace.

5. The corrosion resistant marine plate aluminum alloy slab ingot of claim 1 wherein The 2# covering agent in step two is composed of 45% KCl, 30% NaCl and 25% Na3AlF6 by mass percentage.

6. The corrosion resistant marine plate aluminum alloy slab ingot of claim 1 wherein The argon-chlorine mixed gas is introduced at a rate of 0.15 to 0.20 m 3 / min in step two.

7. The corrosion resistant marine plate aluminum alloy slab ingot of claim 1 wherein The volume ratio of argon and chlorine in the argon-chlorine mixed gas in step two is 1:

1.

8. The corrosion resistant marine plate aluminum alloy slab ingot of claim 1 wherein The semi-continuous casting was performed in Step 3 at a casting speed of 48 mm / min, a casting temperature of 750 to 770 °C, a casting cooling water flow rate of 45 m 3 / h, and a crystallizer metal level of 85 mm.

9. The corrosion resistant marine plate aluminum alloy slab ingot of claim 1 wherein The semi-continuous casting was performed at a recasting speed of 50 mm / min, a casting temperature of 750 to 770 °C, a casting cooling water flow rate of 45 m 3 / h, and a crystallizer metal level of 90 mm.

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