Manufacturing method of 5-series thick plate for aerospace

Abstract

The invention discloses a manufacturing method of a 5-series thick plate for aerospace, relates to a manufacturing method of an aluminum alloy plate, and provides the manufacturing method of the 5-series thick plate for aerospace in order to solve the problem that the flaw detection passing rate of alloy is low due to gaps in melt. The method comprises the following steps: 1, smelting an aluminum alloy melt; 2, casting; 3, milling and sawing; 4, heating; 5, rolling; by improving the rolling process, the problem that the flaw detection yield is too low is effectively solved while various indexes are guaranteed, and the flaw detection yield is increased to 80%-85%. The method is applied to the field of manufacturing of aluminum alloy plates.

Description

Technical Field

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

[0002] 5XXX series aluminum alloys have the characteristics of high strength, low density, good fatigue and welding performance, good resistance to marine atmospheric corrosion, etc., and are widely used in important industrial fields such as aerospace, shipbuilding, and bridge construction. In the manufacture of spacecraft, 5xxx series aluminum alloys are mainly used to manufacture important parts such as skins, aircraft plate welded parts, fuel tanks, and ducts. 5A06 aluminum alloy is an early and widely used high-magnesium aluminum alloy. At present, the mainstream ordering requirements for 5A06 alloy require flaw detection. However, as a high-magnesium aluminum alloy, 5A06 alloy is very easy to produce voids in the melt due to hydrogen absorption, and the flaw detection pass rate of conventional manufacturing methods is not high. 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 aerospace thick plates.

[0004] The manufacturing method of a 5 series aerospace thick plate of the present invention is carried out according to 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 5h-7h 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-cooling casting method;

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

[0008] 4. Heat the ingot after the treatment in 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 heated ingot in step 4, set the rolling temperature to 430°C to 470°C, and the rolling speed to 1.2m / s to 2.0m / s; then shear, stretch, inspect and then perform precision sawing to obtain finished plates.

[0010] The present invention is combined with actual production, and designs a new heat treatment process system for 5A06 alloy with a thickness of more than 40 μm, so as to practically produce 5A06-H112 aluminum alloy plates that meet the requirements of GB / T3880 standard, thereby solving 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 of more than 40 mm.

[0013] 2. The flaw detection yield rate of the 5A06-H112 alloy prepared 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 obtained 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 rate while ensuring various indicators by improving the rolling process. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0018] Specific implementation method 1: In this implementation method, a 5 series aerospace thick plate manufacturing method 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 5h-7h 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-cooling casting method;

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

[0022] 4. Heat the ingot after the treatment in 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 heated ingot in step 4, set the rolling temperature to 430°C to 470°C, and the rolling speed to 1.2m / s to 2.0m / s; then shear, stretch, inspect and then perform precision sawing to obtain finished plates.

[0024] Specific embodiment 2: This embodiment is different 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 those of specific embodiment 1.

[0025] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that the milling surface in step 3 is: 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. The rest is the same as specific implementation method 1 or 2.

[0026] Specific embodiment 4: This embodiment is different from specific embodiments 1 to 4 in that the casting process parameters are: casting temperature is 710℃~730℃, casting speed is 40mm / min~50mm / min, liquid level is 60mm~70mm, water flow is 95t / h~105t / h. Others are the same as specific embodiments 1 to 4.

[0027] Specific implementation method 5: This implementation method is different from specific implementation methods 2 to 4 in that: in step 3, the surface of the ingot is milled, the ingot milling amount is 5mm to 30mm, and the maximum milling amount is ≤40mm. The rest is the same as specific implementation methods 2 to 4.

[0028] Specific implementation method 6: This implementation method is different from specific implementation methods 2 to 5 in that step 4 is heated in a pusher type heating furnace or a trolley type heating furnace. The rest is the same as specific implementation methods 2 to 5.

[0029] Specific embodiment 7: This embodiment differs from specific embodiments 2 to 6 in that: in step 5, the rolling is performed at a reduction of 8 to 20 mm per pass to 250 mm, and then the rolling is performed at 250 mm to 210 mm to 170 mm to 130 mm to 120 mm to 110 mm; and then the rolling is performed at a reduction of 20 to 30 mm per pass to the required thickness. The rest is the same as specific embodiments 2 to 6.

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

[0031] Specific embodiment 8: This embodiment is different from specific embodiments 2 to 7 in that three passes are selected at random from the 6th, 8th, 10th and 12th passes for rolling edge, and each pass is rolled edged 6 times, and the amount of each rolling edge is 5mm to 10mm. The rest is 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 by heavy shearing or light shearing with a rolling mill, and the length shearing error is controlled to be ≤100mm. The rest is 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%. The rest is 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 several 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 according to 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-cooling casting method;

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

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

[0042] Fifth, the heated ingot in step 4 is rolled, and the rolling temperature is set to 450°C and the rolling speed is 1.7m / s; during rolling, the ingot is rolled to 250mm with a reduction of 8-20mm per pass, and then rolled to 250mm-210mm-170mm-130mm-120mm-110mm; and then rolled to 80mm with a reduction of 20-30mm per pass. Roll edge is performed in the 6th, 8th and 12th passes, and the roll edge is rolled 6 times per pass, and the roll edge amount is 10mm each time, and then shearing, stretching (stretching amount ≤1.5%), flaw detection and precision sawing are performed to obtain the finished plate.

[0043] The 5A06-H112 alloy obtained in this embodiment is compared with the flaw detection yield rate of the 5A06-H112 alloy produced by the normal manufacturing process of uniformly increasing the number of rolling passes from small to large without adding roller edges; 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 obtained plate 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 5h-7h to obtain an aluminum alloy melt; 2. Casting the aluminum alloy solution produced in step 1 into an ingot using a semi-continuous water-cooling casting method; 3. milling and sawing the ingot produced in step 2; 4. Heat the ingot after the treatment in 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 heated ingot in step 4, set the rolling temperature to 430°C to 470°C, and the rolling speed to 1.2m / s to 2.0m / s; then shear, stretch, inspect and then perform precision sawing to obtain finished plates.

2. A method for manufacturing a 5-series aerospace thick plate according to claim 1, characterized in that: The crystallizer used in the semi-continuous water-cooled casting in step 2 has a thickness of 520 mm and a width of 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 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 three: 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 aerospace thick plate according to claim 1, characterized in that: During step 5 rolling, the steel is rolled to 250 mm with a reduction of 8 to 20 mm per pass, and then rolled to 250 to 210 mm to 170 mm to 130 mm to 120 mm to 110 mm; and then rolled to the required thickness with a reduction of 20 to 30 mm per pass.

8. A method for manufacturing a 5-series aerospace thick plate according to claim 1 or 7, characterized in that: Randomly select three passes from the 6th, 8th, 10th and 12th passes for rolling edge, and roll edge 6 times in each pass, with each rolling edge amount being 5mm to 10mm.

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

10. 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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