Manufacturing method of heat-treatment-free high-strength aluminum alloy bar for stirring friction 3D printing welding material

Abstract

The invention discloses a manufacturing method of a heat-treatment-free high-strength aluminum alloy bar for a friction-stir 3D printing welding material. The technical problem that in the prior art, the higher and higher requirements of aerospace crafts for the strength of parts cannot be met is solved. The method comprises the following steps: casting a round cast ingot with the diameter of 162mm; heating is performed; performing extrusion; performing online water cooling; drawing is conducted; stretching is conducted; and interrupting. According to the friction stir welding 3D printing part manufactured through the bar, 90%-95% of the original strength of a welding material is reserved, deformation treatment and solid solution and quenching treatment are not needed any more, the strength of the part can reach 420 MPa or above, and the actually measured strength is equivalent to that of a conventional 2xxx series high-strength aluminum alloy such as 2024 for aerospace. The welding material manufactured through the method is used for manufacturing stirring friction 3D printing parts.

Description

Technical Field

[0001] The invention relates to the field of methods for manufacturing high-strength aluminum alloy bars. Background Art

[0002] Friction stir welding (3D printing) is a new additive manufacturing technology developed in recent years. It's used to manufacture complex, integrated components for aerospace applications. Compared to more common fusion welding (3D printing) techniques, it maximizes the preservation of the weld material's original microstructure and properties, avoiding the melting of the weld material in conventional additive manufacturing, which results in a completely cast microstructure (essentially prohibiting its application in the aerospace industry). The friction stir welding (3D printing) process also requires high temperatures, approximately 580°C-620°C, leaving the material in a semi-solid state. This high-temperature treatment of conventional aluminum alloys can compromise component performance. Depending on the material, heat-treatable 2-, 4-, 6-, and 7-series aluminum alloys can retain approximately 40%-50% of the weld material, while non-heat-treatable 5-series alloys can retain approximately 50%-60%. Furthermore, due to cost-effectiveness, this technology is more suitable for manufacturing complex, integrated components. To ensure dimensional accuracy, further deformation, solution treatment, and quenching to enhance strength are unsuitable. As a result, this technology is unable to adapt to the increasingly higher requirements for component strength in aerospace vehicles, and its promotion and application are severely restricted. Summary of the Invention

[0003] In order to solve the technical problem that the existing technology cannot adapt to the increasingly higher requirements of aerospace vehicles for the strength of components, the present invention provides a method for manufacturing heat-treatment-free high-strength aluminum alloy bars for stir friction 3D printing welding materials.

[0004] The present invention aims to solve the pain points in welding material selection during the promotion of stir friction welding 3D printing additive manufacturing technology in the aerospace field. Through research, the influence of high-temperature softening on the microstructure and properties of welding materials after hardening is clarified, and the deformation processing method of conventional extruded materials is improved to produce stir friction welding 3D printing additive manufacturing welding materials that meet the needs of the aerospace field.

[0005] A method for manufacturing a heat-treatment-free high-strength aluminum alloy bar for friction stir 3D printing welding materials, the method specifically comprising the following steps:

[0006] 1. Casting of round ingots with a diameter of 162 mm:

[0007] ① According to the weight percentage of Sc: 0.45% to 0.55%, Zr: 0.15% to 0.25%, Mn: 0.3% to 0.5%, Mg: 7.85% to 8.05%, Ti: 0.02% to 0.05%, individual impurities < 0.05%, total impurities ≤ 0.15%, and the balance is Al, pure aluminum ingot, aluminum-titanium master alloy, aluminum-chromium master alloy, cathode electrolytic copper, magnesium ingot and aluminum ingot for remelting are weighed respectively, and then added into a dry melting furnace, and the temperature is 780°C to 830°C to obtain an aluminum alloy melt;

[0008] ② The aluminum alloy melt obtained in step ① is introduced into a static furnace. When the melt temperature is 710°C to 760°C, Cl2 gas is introduced into the static furnace for refining, and then the melt is allowed to stand for 40 to 60 minutes to obtain a casting melt.

[0009] ③ The casting melt obtained in ② is degassed, and then cast into a round ingot with a diameter of 170 mm at a casting speed of 40 mm / min to 65 mm / min and a cooling water pressure of 0.05 MPa to 0.25 MPa, which is then machined to obtain a round ingot with a diameter of 162 mm;

[0010] 2. Place the 162 mm diameter round ingot obtained in step 1 into a heating furnace and heat it to a temperature of 450° C. to 480° C.

[0011] 3. Extruding the round ingot after the treatment in step 2 on a 1200-ton extrusion press at an extrusion speed of 0.01 mm / s to 0.1 mm / s, controlling the extrusion ratio to be ≥40, to obtain a rod with a diameter of 10 to 20 mm, and the temperature of the extruded rod is 470°C to 490°C;

[0012] 4. The rod obtained in step 3 is subjected to online water cooling;

[0013] 5. The rod obtained in step 4 is heated online to 100-150°C, the deformation is controlled to 20%-30%, and the rod is drawn to a diameter of 8mm-17mm using a drawing machine, and then cooled online with water to below 30°C, and the shrinkage rate is controlled to be ≥50°C / s;

[0014] 6. The rod obtained in step 5 is straightened by stretching process, and the stretching amount is controlled to be 1%~3%. After stretching, the straightness of the rod is ≤1mm / m;

[0015] 7. Cut the rod obtained in step 6 into a length of 990-1000 mm to obtain the heat-treatment-free high-strength aluminum alloy rod for stir friction 3D printing welding material, thereby completing the preparation.

[0016] The present invention discloses a heat-treatment-free high-strength aluminum alloy bar for friction stir welding 3D printing, which can address the pain points encountered in the promotion of friction stir welding 3D printing and greatly expand its application in the aerospace field. The manufacturing method disclosed herein, by modifying the processing technology, enables the parts manufactured by friction stir welding 3D printing to retain 90%-95% of the original strength of the welding material. Without the need for deformation, solution treatment, and quenching, the strength of the parts can reach over 420 MPa. The measured strength is comparable to that of conventional 2xxx series high-strength aluminum alloys such as 2024 used in aerospace.

[0017] Beneficial effects of the present invention:

[0018] The present invention, through a unique chemical composition ratio, controls the content of Sc and Zr elements, laying the foundation for the formation of high-temperature particle phases during subsequent deformation processing. The addition of Mg to the alloy not only improves the basic strength of the welding material, but also increases the processing performance during stir friction welding 3D printing, making the process smoother, and thirdly, ensures the corrosion resistance of the product. The manufacturing method of the present invention uses high-temperature and high-extrusion ratio deformation strengthening, and through rapid water cooling after extrusion, the high-temperature particle phase formed by the Sc and Zr elements in the structure is fully dissolved and dispersed into the matrix, achieving a combination of solid solution strengthening and deformation strengthening. Through medium and low temperature controlled cold deformation and rapid water cooling, it not only promotes the generation of a large number of dislocations in the matrix, but also promotes a greater pinning effect of the high-temperature particles relative to the dislocations, raising the recrystallization temperature of the structure (the recrystallization temperature is 580°C, and the temperature for rapid and full recrystallization is raised to 630°C), ensuring the high-temperature stability of the structure. Although the weld material temperature rises to a semi-solidified state during friction stir 3D printing (reaching 600-620°C), the actual temperature is significantly lower than the dissolution temperature of the high-temperature particle phase formed by Sc and Zr elements (which dissolves at temperatures above 680°C). Therefore, the high-temperature particle phase remains, maintaining a significant pinning effect on structural dislocations. Furthermore, due to the deformation of the weld material during friction stir 3D printing (primarily subject to compressive and tensile stresses), the vast majority of dislocations in the original weld material remain. Furthermore, while structural recrystallization occurs, the rate is slow, and the thickness of the 3D printed product increases by approximately 1-2 mm / s. This temperature can be reduced to below the recrystallization temperature within 15 seconds through natural air cooling. The weld material manufactured using the present invention and parts manufactured using friction stir 3D printing technology have a measured tensile strength exceeding 430 MPa. No further deformation, solution hardening, or quenching is required, and the measured strength is comparable to conventional 2xxx series high-strength aluminum alloys such as 2024 used in aerospace applications.

[0019] The welding material manufactured by the present invention is used for manufacturing stir friction 3D printing parts. DETAILED DESCRIPTION

[0020] Specific embodiment 1: This embodiment provides a method for manufacturing a heat-treatment-free high-strength aluminum alloy bar for friction stir 3D printing welding materials, which is specifically carried out in the following steps:

[0021] 1. Casting of round ingots with a diameter of 162 mm:

[0022] ① According to the weight percentage of Sc: 0.45% to 0.55%, Zr: 0.15% to 0.25%, Mn: 0.3% to 0.5%, Mg: 7.85% to 8.05%, Ti: 0.02% to 0.05%, individual impurities < 0.05%, total impurities ≤ 0.15%, and the balance is Al, pure aluminum ingot, aluminum-titanium master alloy, aluminum-chromium master alloy, cathode electrolytic copper, magnesium ingot and aluminum ingot for remelting are weighed respectively, and then added into a dry melting furnace, and the temperature is 780°C to 830°C to obtain an aluminum alloy melt;

[0023] ② The aluminum alloy melt obtained in step ① is introduced into a static furnace. When the melt temperature is 710°C to 760°C, Cl2 gas is introduced into the static furnace for refining, and then the melt is allowed to stand for 40 to 60 minutes to obtain a casting melt.

[0024] ③ The casting melt obtained in ② is degassed, and then cast into a round ingot with a diameter of 170 mm at a casting speed of 40 mm / min to 65 mm / min and a cooling water pressure of 0.05 MPa to 0.25 MPa, which is then machined to obtain a round ingot with a diameter of 162 mm;

[0025] 2. Place the 162 mm diameter round ingot obtained in step 1 into a heating furnace and heat it to a temperature of 450° C. to 480° C.

[0026] 3. Extruding the round ingot after the treatment in step 2 on a 1200-ton extrusion press at an extrusion speed of 0.01 mm / s to 0.1 mm / s, controlling the extrusion ratio to be ≥40, to obtain a rod with a diameter of 10 to 20 mm, and the temperature of the extruded rod is 470°C to 490°C;

[0027] 4. The rod obtained in step 3 is subjected to online water cooling;

[0028] 5. The rod obtained in step 4 is heated online to 100-150°C, the deformation is controlled to 20%-30%, and the rod is drawn to a diameter of 8mm-17mm using a drawing machine, and then cooled online with water to below 30°C, and the shrinkage rate is controlled to be ≥50°C / s;

[0029] 6. The rod obtained in step 5 is straightened by stretching process, and the stretching amount is controlled to be 1%~3%. After stretching, the straightness of the rod is ≤1mm / m;

[0030] 7. Cut the rod obtained in step 6 into a length of 990-1000 mm to obtain the heat-treatment-free high-strength aluminum alloy rod for stir friction 3D printing welding material, thereby completing the preparation.

[0031] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that step ② is refined for 30-35 minutes. Other aspects are the same as specific embodiment 1.

[0032] Specific embodiment 3: This embodiment differs from specific embodiment 1 or 2 in that step 3 is performed at a casting speed of 50 mm / min to 60 mm / min and a cooling water pressure of 0.08 MPa to 0.20 MPa. The rest is the same as specific embodiment 1 or 2.

[0033] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that: in step 2, the temperature of the round ingot is heated to 470° C. to 480° C. The rest is the same as specific embodiments 1 to 3.

[0034] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that: in step 3, the extrusion ratio is controlled to be ≥ 50. The rest is the same as specific embodiments 1 to 4.

[0035] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the temperature of the extruded rod is controlled to be 480° C. to 490° C. in step 3. The rest is the same as specific embodiments 1 to 5.

[0036] Specific embodiment 7: This embodiment differs from any one of specific embodiments 1 to 6 in that: in step 4, the online water cooling is performed to below 30°C, and the shrinkage rate is controlled to be ≥100°C / s. Other aspects are the same as any one of specific embodiments 1 to 6.

[0037] Specific embodiment eight: This embodiment differs from specific embodiments one to seven in that: in step five, the online water cooling is controlled to have a cooling speed of ≥50°C / s and a cooling temperature of ≤30°C. Other aspects are the same as specific embodiments one to seven.

[0038] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that step 5 is online heating to 100-120° C. The rest is the same as specific embodiments 1 to 8.

[0039] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that the stretching amount in step 6 is controlled to be 1.5% to 2.5%. Other aspects are the same as specific embodiments 1 to 9.

[0040] 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.

[0041] Example 1:

[0042] A method for manufacturing a heat-treatment-free high-strength aluminum alloy bar for friction stir 3D printing welding materials is specifically carried out in the following steps:

[0043] 1. Casting of round ingots with a diameter of 162 mm:

[0044] ① According to the weight percentage of Sc: 0.50% to 0.55%, Zr: 0.20% to 0.25%, Mn: 0.40% to 0.50%, Mg: 7.95% to 8.05%, Ti: 0.02% to 0.05%, individual impurities < 0.05%, total impurities ≤ 0.15%, and the balance being Al, pure aluminum ingot, aluminum-titanium master alloy, aluminum-chromium master alloy, cathode electrolytic copper, magnesium ingot and aluminum ingot for remelting are weighed respectively, and then added into a dry melting furnace, and the temperature is 780° C. to 830° C. to obtain an aluminum alloy melt;

[0045] ② The aluminum alloy melt obtained in step ① is introduced into a static furnace. When the melt temperature is 710°C to 760°C, Cl2 gas is introduced into the static furnace for refining for 30 to 35 minutes, and then the mixture is allowed to stand for 40 to 60 minutes to obtain a casting melt.

[0046] ③ The casting melt obtained in ② is degassed, and then cast into a round ingot with a diameter of 170 mm at a casting speed of 40 mm / min to 65 mm / min and a cooling water pressure of 0.05 MPa to 0.25 MPa, which is then machined to obtain a round ingot with a diameter of 162 mm;

[0047] 2. Place the round ingot with a diameter of 162 mm obtained in step 1 into a heating furnace and heat it to a temperature of 470° C. to 480° C.;

[0048] 3. The round ingot (measured temperature of 470-480°C) after the treatment in step 2 was extruded on a 1200-ton extrusion press at an extrusion speed of 0.01 mm / s to 0.1 mm / s, with an extrusion ratio of 90.8, to obtain a rod with a diameter of 17 mm. The temperature of the extruded rod was 470-490°C.

[0049] 4. The rod obtained in step 3 is subjected to online water cooling, rapidly cooled to below 30°C, and the shrinkage rate is controlled to be ≥50°C / s;

[0050] 5. The rod obtained in step 4 is heated online to 100-120°C, the deformation is controlled to 20%-30%, and the rod is drawn to a diameter of 15 mm using a drawing machine, and then water-cooled online, the shrinkage speed is controlled to be ≥50°C / s, and the rod is cooled to a temperature of ≤30°C;

[0051] 6. The rod obtained in step 5 is straightened by stretching process, and the stretching amount is controlled to be 1%~3%. After stretching, the straightness of the rod is ≤1mm / m;

[0052] 7. Cut the rod obtained in step 6 into a length of 990-1000 mm to obtain the heat-treatment-free high-strength aluminum alloy rod for stir friction 3D printing welding material, thereby completing the preparation.

[0053] Example 2:

[0054] A method for manufacturing a heat-treatment-free high-strength aluminum alloy bar for friction stir 3D printing welding materials is specifically carried out in the following steps:

[0055] 1. Casting of round ingots with a diameter of 162 mm:

[0056] ① According to the weight percentage of Sc: 0.50% to 0.55%, Zr: 0.20% to 0.25%, Mn: 0.40% to 0.50%, Mg: 7.95% to 8.05%, Ti: 0.02% to 0.05%, individual impurities < 0.05%, total impurities ≤ 0.15%, and the balance being Al, pure aluminum ingot, aluminum-titanium master alloy, aluminum-chromium master alloy, cathode electrolytic copper, magnesium ingot and aluminum ingot for remelting are weighed respectively, and then added into a dry melting furnace, and the temperature is 780° C. to 830° C. to obtain an aluminum alloy melt;

[0057] ② The aluminum alloy melt obtained in step ① is introduced into a static furnace. When the melt temperature is 710°C to 760°C, Cl2 gas is introduced into the static furnace for refining for 30 to 35 minutes, and then the mixture is allowed to stand for 40 to 60 minutes to obtain a casting melt.

[0058] ③ The casting melt obtained in ② is degassed, and then cast into a round ingot with a diameter of 170 mm at a casting speed of 40 mm / min to 65 mm / min and a cooling water pressure of 0.05 MPa to 0.25 MPa, which is then machined to obtain a round ingot with a diameter of 162 mm;

[0059] 2. Place the round ingot with a diameter of 162 mm obtained in step 1 into a heating furnace and heat it to a temperature of 470° C. to 480° C.;

[0060] 3. The round ingot (measured temperature of 470-480°C) after the treatment in step 2 was extruded on a 1200-ton extrusion press at an extrusion speed of 0.01 mm / s to 0.1 mm / s, with an extrusion ratio of 66.1, to obtain a rod with a diameter of 11.5 mm. The temperature of the extruded rod was 470-490°C.

[0061] 4. The rod obtained in step 3 is subjected to online water cooling, rapidly cooled to below 30°C, and the shrinkage rate is controlled to be ≥50°C / s;

[0062] 5. The rod obtained in step 4 is heated online to 100-120°C, the deformation is controlled to 20%-30%, and the rod is drawn to a diameter of 10.0 mm using a drawing machine, and then water-cooled online, the shrinkage rate is controlled to be ≥50°C / s, and the rod is cooled to a temperature of ≤30°C;

[0063] 6. The rod obtained in step 5 is straightened by stretching process, and the stretching amount is controlled to be 1%~3%. After stretching, the straightness of the rod is ≤1mm / m;

[0064] 7. Cut the rod obtained in step 6 into a length of 990-1000 mm to obtain the heat-treatment-free high-strength aluminum alloy rod for stir friction 3D printing welding material, thereby completing the preparation.

[0065] The rods prepared in the embodiment were tested according to the GB / T 16865-2013 test standard, and the results are shown in Table 1.

[0066] Table 1

[0067] From the above results, it can be seen that the aluminum alloy rods prepared in the embodiment are used as welding materials, and the products prepared by stir friction 3D printing technology, without deformation treatment and solid solution and quenching treatment, have measured strength and measured tensile strength of more than 430 MPa, which is comparable to conventional 2024 and other 2xxx series high-strength aluminum alloys used in aerospace, and meets the strength performance requirements of most complex structural parts in the aerospace field, greatly expanding the application scope of stir friction 3D printing technology in the aerospace field.

Claims

1. A method for manufacturing heat-treatment-free high-strength aluminum alloy bars for friction stir 3D printing welding materials, characterized in that The method is specifically carried out in the following steps:

1. Casting of round ingots with a diameter of 162 mm: ① According to the weight percentage of Sc: 0.45% to 0.55%, Zr: 0.15% to 0.25%, Mn: 0.3% to 0.5%, Mg: 7.85% to 8.05%, Ti: 0.02% to 0.05%, individual impurities < 0.05%, total impurities ≤ 0.15%, and the balance is Al, pure aluminum ingot, aluminum-titanium master alloy, aluminum-chromium master alloy, cathode electrolytic copper, magnesium ingot and aluminum ingot for remelting are weighed respectively, and then added into a dry melting furnace, and the temperature is 780°C to 830°C to obtain an aluminum alloy melt; ② The aluminum alloy melt obtained in step ① is introduced into a static furnace. When the melt temperature is 710°C to 760°C, Cl2 gas is introduced into the static furnace for refining, and then the melt is allowed to stand for 40 to 60 minutes to obtain a casting melt. ③ The casting melt obtained in ② is degassed, and then cast into a round ingot with a diameter of 170 mm at a casting speed of 40 mm / min to 65 mm / min and a cooling water pressure of 0.05 MPa to 0.25 MPa, which is then machined to obtain a round ingot with a diameter of 162 mm; 2. Place the 162 mm diameter round ingot obtained in step 1 into a heating furnace and heat it to a temperature of 450° C. to 480° C.

3. Extruding the round ingot after the treatment in step 2 on a 1200-ton extrusion press at an extrusion speed of 0.01 mm / s to 0.1 mm / s, controlling the extrusion ratio to be ≥40, to obtain a rod with a diameter of 10 to 20 mm, and the temperature of the extruded rod is 470°C to 490°C; 4. The rod obtained in step 3 is subjected to online water cooling; 5. The rod obtained in step 4 is heated online to 100-150°C, the deformation is controlled to 20%-30%, and the rod is drawn to a diameter of 8mm-17mm using a drawing machine, and then cooled online with water to below 30°C, and the shrinkage rate is controlled to be ≥50°C / s; 6. The rod obtained in step 5 is straightened by stretching process, and the stretching amount is controlled to be 1%~3%. After stretching, the straightness of the rod is ≤1mm / m; 7. Cut the rod obtained in step 6 into a length of 990-1000 mm to obtain the heat-treatment-free high-strength aluminum alloy rod for stir friction 3D printing welding material, thereby completing the preparation.

2. The method for manufacturing a heat-treatment-free high-strength aluminum alloy bar for friction stir 3D printing welding materials according to claim 1, characterized in that Step ②: Refine for 30-35 minutes.

3. The method for manufacturing a heat-treatment-free high-strength aluminum alloy bar for friction stir 3D printing welding materials according to claim 1, characterized in that Step ③ Casting is carried out at a casting speed of 50 mm / min to 60 mm / min and a cooling water pressure of 0.08 MPa to 0.20 MPa.

4. The method for manufacturing a heat-treatment-free high-strength aluminum alloy bar for friction stir 3D printing welding materials according to claim 1, characterized in that Step 2: Heat the round ingot to a temperature of 470°C to 480°C.

5. The method for manufacturing a heat-treatment-free high-strength aluminum alloy bar for friction stir 3D printing welding materials according to claim 1, characterized in that Step 3: Control the extrusion ratio to be ≥50.

6. The method for manufacturing a heat-treatment-free high-strength aluminum alloy bar for friction stir 3D printing welding materials according to claim 1, characterized in that Step 3: Control the temperature of the extruded rod to be 480°C~490°C.

7. The method for manufacturing a heat-treatment-free high-strength aluminum alloy bar for friction stir 3D printing welding materials according to claim 1, characterized in that In step 4, the online water cooling is performed to below 30° C., and the shrinkage speed is controlled to be ≥100° C. / s.

8. The method for manufacturing a heat-treatment-free high-strength aluminum alloy bar for friction stir 3D printing welding materials according to claim 1, characterized in that In step 5, the online water cooling is performed, and the shrinkage rate is controlled to be ≥50°C / s, and the temperature is cooled to ≤30°C.

9. The method for manufacturing a heat-treatment-free high-strength aluminum alloy bar for friction stir 3D printing welding materials according to claim 1, characterized in that Step 5: Online heating to 100~120℃.

10. The method for manufacturing a heat-treatment-free high-strength aluminum alloy bar for friction stir 3D printing welding materials according to claim 1, characterized in that Step 6: Control the stretching amount to 1.5%~2.5%.

Images