A method for manufacturing 5 series thick plates for aerospace

Abstract

A method for manufacturing 5-series thick plates for aerospace applications relates to a method for manufacturing aluminum alloy plates. To address the problem of low alloy flaw detection pass rates due to voids in the melt, the present invention provides a method for manufacturing 5-series thick plates for aerospace applications. The present invention comprises the following steps: 1. Melting the aluminum alloy melt; 2. Casting; 3. Milling and sawing; 4. Heating; and 5. Rolling. By improving the rolling process, the present invention effectively addresses the problem of low flaw detection yield rates while ensuring various performance indicators, increasing the flaw detection yield rate to 80% to 85%. This application is applicable to the manufacturing of aluminum alloy plates.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a 5 series thick plate for aerospace. Background Art

[0002] 5XXX series aluminum alloys feature high strength, low density, excellent fatigue and weldability, and good resistance to marine atmospheric corrosion. They are widely used in key industrial sectors such as aerospace, shipbuilding, and bridge construction. In spacecraft manufacturing, 5XXX series aluminum alloys are primarily used to manufacture critical components such as skins, aircraft plate weldments, fuel tanks, and ducting systems. 5A06 aluminum alloy is a high-magnesium aluminum alloy that was widely used earlier. Currently, mainstream orders for 5A06 alloy require nondestructive testing (NDT). However, as a high-magnesium aluminum alloy, 5A06 alloy is highly susceptible to voids in the melt due to hydrogen absorption, resulting in a low NDT pass rate using conventional manufacturing methods. Summary of the Invention

[0003] In order to solve the problem of low flaw detection pass rate of alloy due to voids in the melt, the present invention provides a method for manufacturing 5 series thick plates for aerospace.

[0004] The manufacturing method of a 5 series aerospace thick plate of the present invention is carried out by the following steps:

[0005] 1. Weigh raw materials according to mass fractions of Si: ≤0.4%, Fe: 0.4%, Cu: 0.1%, Mn: 0.5%-0.8%, Mg: 5.8%-6.8%, Zn: 0.2%, Ti: ≤0.02%-0.1%, Be: 0.0001%-0.005% and the balance Al, and smelt the weighed raw materials at a temperature of 700° C.-750° C. for 5 h-7 h to obtain an aluminum alloy melt;

[0006] 2. Casting the aluminum alloy solution produced in step 1 into an ingot using a semi-continuous water-cooled casting method;

[0007] 3. Milling and sawing the ingot produced in step 2;

[0008] 4. Heat the ingot after step 3, set the heating temperature to 550°C, and the heating time to 6h~7h; change the heating temperature to 480°C, and the metal furnace temperature to 430°C~470°C;

[0009] 5. Roll the ingot heated in step 4, set the rolling temperature to 430° C. to 470° C., and the rolling speed to 1.2 m / s to 2.0 m / s; then shear, stretch, inspect for flaws, and perform precision sawing to obtain finished plates.

[0010] The present invention is based on actual production and designs a new heat treatment process system for 5A06 alloy with a thickness of more than 40 μm, which can effectively produce 5A06-H112 aluminum alloy plates that meet the requirements of GB / T3880 standard, and solve the problem of low yield of 5A06 alloy H112 state plates (hereinafter referred to as "5A06-H112" alloy plates) produced in my country.

[0011] Beneficial effects of the present invention:

[0012] 1. The present invention improves the ingot rolling process of 5A06-H112 alloy with a thickness greater than 40 mm.

[0013] 2. The flaw detection yield rate of the 5A06-H112 alloy produced by the present invention is compared with that of the 5A06-H112 alloy produced by the normal manufacturing process; its flaw detection yield rate is increased from the original 35% to 40% to 80% to 85%; at the same time, its tensile strength meets the standard requirement range of ≥295MPa, the yield strength meets the standard requirement range of ≥135MPa, and the elongation meets the standard requirement of 6%; other indicators also fully meet the standard requirements, and after the stretching process, the flatness of the produced plate can also be guaranteed, which can be applied to actual production.

[0014] 3. The present invention provides a new 5A06-H112 alloy manufacturing method, which effectively solves the problem of low flaw detection yield while ensuring various indicators by improving the rolling process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A is a physical diagram of a thick plate prepared in the embodiment;

[0016] Figure 2 Figure B is a physical picture of a thick plate prepared in Example;

[0017] Figure 3 Figure C is a physical picture of the thick plate prepared in Example. DETAILED DESCRIPTION

[0018] Specific embodiment 1: In this embodiment, a method for manufacturing a 5 series aerospace thick plate is carried out according to the following steps:

[0019] 1. Weigh raw materials according to mass fractions of Si: ≤0.4%, Fe: 0.4%, Cu: 0.1%, Mn: 0.5%-0.8%, Mg: 5.8%-6.8%, Zn: 0.2%, Ti: ≤0.02%-0.1%, Be: 0.0001%-0.005% and the balance Al, and smelt the weighed raw materials at a temperature of 700° C.-750° C. for 5 h-7 h to obtain an aluminum alloy melt;

[0020] 2. Casting the aluminum alloy solution produced in step 1 into an ingot using a semi-continuous water-cooled casting method;

[0021] 3. Milling and sawing the ingot produced in step 2;

[0022] 4. Heat the ingot after step 3, set the heating temperature to 550°C, and the heating time to 6h~7h; change the heating temperature to 480°C, and the metal furnace temperature to 430°C~470°C;

[0023] 5. Roll the ingot heated in step 4, set the rolling temperature to 430° C. to 470° C., and the rolling speed to 1.2 m / s to 2.0 m / s; then shear, stretch, inspect for flaws, and perform precision sawing to obtain finished plates.

[0024] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the thickness of the crystallizer used in step 2, semi-continuous water-cooled casting, is 520 mm and the width is 1620 mm. Other aspects are the same as specific embodiment 1.

[0025] Specific embodiment 3: This embodiment differs from specific embodiments 1 or 2 in that, in step 3, the milling surface is performed with the following conditions: the hardness of the casting circulating water is less than 8dH, the pH value is 7-8, the casting water temperature is ≤24°C, the suspended solids are less than 10mg / L, and the solid particle size is less than 1.5mm. Other aspects are the same as specific embodiments 1 or 2.

[0026] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 4 in that the casting process parameters are: casting temperature of 710°C to 730°C, casting speed of 40mm / min to 50mm / min, liquid level of 60mm to 70mm, and water flow rate of 95t / h to 105t / h. Other parameters are the same as specific embodiments 1 to 4.

[0027] Specific embodiment 5: This embodiment differs from specific embodiments 2 to 4 in that: in step 3, the ingot surface is milled, the ingot milling amount is 5mm to 30mm, and the maximum milling amount is ≤40mm. Other aspects are the same as specific embodiments 2 to 4.

[0028] Specific embodiment 6: This embodiment differs from specific embodiments 2 to 5 in that step 4 is heated in a pusher-type heating furnace or a trolley-type heating furnace. Other aspects are the same as specific embodiments 2 to 5.

[0029] Specific embodiment 7: This embodiment differs from specific embodiments 2 to 6 in that, during step 5, the steel is rolled to 250 mm with a reduction of 8 to 20 mm per pass, then rolled to a thickness of 250 to 210 mm, 170 mm, 130 mm, 120 mm, and 110 mm; and finally rolled to the desired thickness with a reduction of 20 to 30 mm per pass. Other aspects are the same as specific embodiments 2 to 6.

[0030] The reduction amount per pass of 8 to 20 mm in this embodiment is rolled to 250 mm. As the number of passes increases, the reduction amount also increases.

[0031] Specific embodiment 8: This embodiment differs from specific embodiments 2 to 7 in that three passes are randomly selected from the 6th, 8th, 10th, and 12th passes for rolling, with each pass being rolled 6 times, and each rolling amount being 5 mm to 10 mm. Other aspects are the same as specific embodiments 2 to 7.

[0032] Specific embodiment 9: This embodiment differs from specific embodiments 2 to 8 in that in step 5, the length is cut to length using a rolling mill with heavy shearing or light shearing, and the length shearing error is controlled to be ≤100mm. Other aspects are the same as specific embodiments 2 to 8.

[0033] Specific embodiment 10: This embodiment differs from specific embodiments 2 to 9 in that the stretching amount in step 5 is ≤ 1.5%. Other aspects are the same as specific embodiments 2 to 9.

[0034] The content of the present invention is not limited to the content of the above-mentioned embodiments. The combination of one or more specific embodiments can also achieve the purpose of the invention.

[0035] The present application is described in detail below with reference to specific embodiments:

[0036] Example 1

[0037] A method for manufacturing a 5 series aerospace thick plate is carried out in the following steps:

[0038] 1. Weigh raw materials according to mass fractions of Si: ≤0.4%, Fe: 0.4%, Cu: 0.1%, Mn: 0.5%-0.8%, Mg: 5.8%-6.8%, Zn: 0.2%, Ti: ≤0.02%-0.1%, Be: 0.0001%-0.005% and the balance Al, and smelt the weighed raw materials at a temperature of 730° C. for 6 hours to obtain an aluminum alloy melt;

[0039] 2. Casting the aluminum alloy solution produced in step 1 into an ingot using a semi-continuous water-cooled casting method;

[0040] 3. Milling and sawing the ingot produced in step 2;

[0041] 4. Heat the ingot after step 3, set the heating temperature to 550℃, and the heating time to 6h~7h; change the heating temperature to 480℃, heat for 4h, and the metal out of the furnace temperature is 450℃;

[0042] Fifth, the heated ingot from step 4 is rolled at a temperature of 450°C and a speed of 1.7 m / s. The ingot is rolled to a thickness of 250 mm with a reduction of 8 to 20 mm per pass. The ingot is then rolled to a thickness of 250 mm to 210 mm to 170 mm to 130 mm to 120 mm to 110 mm. The ingot is then rolled to a thickness of 80 mm with a reduction of 20 to 30 mm per pass. The ingot is then edged in the sixth, eighth, and twelfth passes, with six edged passes per pass, each edged by 10 mm. The ingot is then sheared, stretched (stretching ≤ 1.5%), inspected for flaws, and precision sawn to produce the finished plate.

[0043] The flaw detection yield rate of the 5A06-H112 alloy prepared in this embodiment is compared with that of the 5A06-H112 alloy produced by the normal manufacturing process in which the number of rolling passes is uniformly increased from small to large and no roll edge is added. The flaw detection yield rate is increased from the original 35% to 40% to 80% to 85%. At the same time, its tensile strength meets the standard requirement range of ≥295MPa, the yield strength meets the standard requirement range of ≥135MPa, and the elongation meets the standard requirement of 6%. Other indicators also fully meet the standard requirements, and after the stretching process, the flatness of the obtained sheet can also be guaranteed (such as Figure 1 、 2 and 3), can be applied to actual production.

Claims

1. A method for manufacturing a 5 series aerospace thick plate, characterized in that: The method proceeds as follows:

1. Weigh raw materials according to mass fractions of Si: ≤0.4%, Fe: 0.4%, Cu: 0.1%, Mn: 0.5%-0.8%, Mg: 5.8%-6.8%, Zn: 0.2%, Ti: ≤0.02%-0.1%, Be: 0.0001%-0.005% and the balance Al, and smelt the weighed raw materials at a temperature of 700° C.-750° C. for 5 h-7 h to obtain an aluminum alloy melt; 2. Casting the aluminum alloy solution produced in step 1 into an ingot using a semi-continuous water-cooled casting method; 3. Milling and sawing the ingot produced in step 2; 4. Heat the ingot after step 3, set the heating temperature to 550°C, and the heating time to 6h~7h; change the heating temperature to 480°C, and the metal furnace temperature to 430°C~470°C; 5. Roll the ingot heated in step 4, set the rolling temperature to 430℃~470℃, the rolling speed to 1.2m / s~2.0m / s, and roll it to 250mm according to the reduction of 8~20mm per pass, and then roll it according to 250mm~210mm~170mm~130mm~120mm~110mm; then roll it to the required thickness according to the reduction of 20-30mm per pass; randomly select three passes from the 6th, 8th, 10th and 12th passes for rolling edge, and roll edge 6 times per pass, with each rolling edge amount of 10mm; after rolling, shear, stretch, inspect and then perform precision sawing to obtain the finished plate.

2. The method for manufacturing a 5 series aerospace thick plate according to claim 1, characterized in that: The thickness of the crystallizer used in the semi-continuous water-cooled casting in step 2 is 520 mm and the width is 1620 mm.

3. The method for manufacturing a 5 series aerospace thick plate according to claim 1, characterized in that: Step 2: The hardness of the circulating water for casting is less than 8dH, the pH value is 7-8, the casting water temperature is ≤24°C, the suspended matter is less than 10mg / L, and the solid particle size is less than 1.5mm.

4. The method for manufacturing a 5 series aerospace thick plate according to claim 1, characterized in that: The casting process parameters of step 2 are: casting temperature of 710°C to 730°C, casting speed of 40mm / min to 50mm / min, liquid level of 60mm to 70mm, and water flow rate of 95t / h to 105t / h.

5. The method for manufacturing a 5 series aerospace thick plate according to claim 1, characterized in that: Step 3: Milling the surface of the ingot, the ingot milling amount is 5mm to 30mm, and the maximum milling amount is ≤40mm.

6. The method for manufacturing a 5 series aerospace thick plate according to claim 1, characterized in that: Step 4: Heating in a pusher type heating furnace or a trolley type heating furnace.

7. The method for manufacturing a 5 series thick plate for aerospace according to claim 1, characterized in that: In step five, heavy shearing or light shearing is performed by a rolling mill to cut to a fixed length, and the length shearing error is controlled to be ≤100mm.

8. The method for manufacturing a 5 series aerospace thick plate according to claim 1, characterized in that: Step 5: The stretching amount is ≤1.5%.

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