Al-Si-Mg-Sc aluminum alloy wire for electric arc additive manufacturing and preparation method of Al-Si-Mg-Sc aluminum alloy wire

Abstract

The invention discloses a preparation method of an Al-Si-Mg-Sc aluminum alloy wire for electric arc additive manufacturing. The preparation method comprises the following steps that S1, molten aluminum is smelted; s2, electromagnetic stirring; s3, refining and degassing; s4, carrying out online filtration; s5, continuous casting is conducted, specifically, the aluminum melt obtained in the step S4 is quantitatively guided into a crystallization wheel and cooled and solidified through the crystallization wheel, and an aluminum rod blank is obtained; the aluminum rod blank obtained in the step S5 is transferred into continuous extrusion equipment, the aluminum rod blank is straightened, oxide skin is scraped off, the aluminum rod blank is washed and then guided into an extrusion wheel groove to be subjected to radial extrusion, and a wire blank is obtained; s7, intermediate annealing; and S8, cleaning and layer winding. According to the Al-Si-Mg-Sc aluminum alloy wire 3D printed part obtained through the method, through T6 heat treatment, the tensile strength is larger than or equal to 340 MPa, the yield strength is larger than or equal to 300 MPa, the ductility is larger than or equal to 8%, chemical components are evenly distributed, the room-temperature mechanical property and high-temperature stability are good, and the isotropic performance is not different.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing metal materials, and in particular to an Al-Si-Mg-Sc aluminum alloy wire for arc additive manufacturing and a preparation method thereof, which is suitable for printing large and complex parts in the aerospace field. Background Art

[0002] Due to its excellent casting performance and good processing performance, Al-Si-Mg aluminum alloy has a wide range of applications in the fields of automobiles, building materials, aerospace, rail transportation, etc. It is the most widely used cast aluminum alloy, and its usage accounts for more than 80% of the total output of aluminum alloy castings. However, with the development of science and technology, modern high-end equipment is rapidly developing in the direction of large-scale, high parameters, high reliability under extremely harsh conditions, and long service life, resulting in the increasing size of key aluminum alloy metal components, increasingly complex structures, and increasing performance requirements. The requirements for aluminum alloy material strength and manufacturing technology are getting higher and higher, and the challenges are becoming increasingly severe. Many large and complex shell parts use aluminum-silicon alloy integral castings. These parts have complex structures, large sizes, and a large difference in wall thickness. The overall performance requirements of the castings are high, and the qualified rate of casting products is low. Therefore, how to ensure the consistency and stability of the overall performance of the castings is the foundation and core key technology of the high-end equipment manufacturing industry.

[0003] With the continuous development of welding technology, various new welding technologies and processes have emerged, especially the development of CMT arc additive manufacturing process, which has greatly improved the 3D printing process of aluminum alloys, making it possible to use Al-Si-Mg aluminum alloy wire for arc additive manufacturing.

[0004] The Chinese patent with publication number CN113649415B discloses a high-strength aluminum alloy welding wire preparation process, which includes: aluminum liquid smelting, furnace refining, online refining, continuous casting, continuous rolling, wire drawing, scraping, ultrasonic cleaning and vacuum packaging; the online refining process controls the hydrogen content in the aluminum liquid to ≤0.1ml / 100g Al, and the electromagnetic filtration device is used for online filtration to effectively remove the inclusions with a size of more than 1μm in the aluminum liquid, which greatly improves the purity of the aluminum liquid, ensures that the internal structure of the alloy is uniform and dense, improves the wire breaking problem in the drawing process, and reduces the formation of inclusions and pore defects in the weld. The casting process adopts a liquid level automatic control system, and the crystallization wheel is cooled independently in different zones to ensure that the metallurgical structure of the cast alloy is uniform and stable. The high-strength aluminum alloy welding wire prepared by this method has stable mechanical properties, uniform and dense structure, and high surface quality, and is suitable for automated welding processes. 1. Equipment: Continuous rolling is a common production process for large aluminum processing enterprises. Compared with continuous extrusion, the equipment investment cost is high. 2. Process: Continuous casting, continuous rolling and drawing are adopted. First, a T-shaped billet (cross-sectional area 3000mm 2), and then transferred to the rolling mill for rolling reduction. The deformation of a single rolling process is small (10-15%), and multiple rolling passes (5-10 passes) are required. Multiple drawing (5-10 passes) are also required to reach φ1.6-1.65mm welding wire. Compared with continuous extrusion, the process route is long. Continuous rolling has a large cross-sectional area of ​​the continuous casting ingot, and the subsequent continuous rolling has many rolling passes, a large investment in rolling mill equipment, a long process route, and high production costs. Summary of the invention

[0005] The present invention aims to provide an Al-Si-Mg-Sc aluminum alloy wire for arc additive manufacturing and a preparation method thereof, which has a short process route, low equipment investment cost and low production cost.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for preparing an Al-Si-Mg-Sc aluminum alloy wire for arc additive manufacturing comprises the following steps:

[0008] S1. Aluminum liquid smelting: adding alloy raw materials into a medium frequency furnace, heating and melting, stirring and fully melting to obtain aluminum liquid, wherein the alloy raw materials include aluminum, silicon, magnesium and scandium;

[0009] S2, electromagnetic stirring: Turn on the electromagnetic stirring power supply to electromagnetically stir the aluminum liquid in S1;

[0010] S3, refining and degassing: the aluminum liquid is refined and degassed;

[0011] S4, online filtration: online degassing, deslagging and filtering of the aluminum melt;

[0012] S5, continuous casting: quantitatively introducing the aluminum melt obtained in S4 into a crystallization wheel, cooling and solidifying through the crystallization wheel to obtain an aluminum rod blank;

[0013] S6, continuous extrusion: the aluminum rod blank obtained in S5 is transferred to a continuous extrusion device, the aluminum rod blank is straightened, the oxide scale is scraped off, the aluminum rod blank is cleaned, and then introduced into the wheel groove of the extrusion wheel for radial extrusion to obtain a wire blank;

[0014] S7, intermediate annealing: annealing, drawing and scraping the wire blank;

[0015] S8, cleaning and layer winding: cleaning the surface of the wire blank, coating with a reagent, and layer winding and packaging to obtain a 3D printing wire;

[0016] Preferably, the rotation speed of the extrusion wheel in the continuous extrusion in S6 is 9-10 rpm; further preferably, a wire blank with a diameter of 2-4 mm is obtained in S6.

[0017] In the step of S6 continuous extrusion, the aluminum rod blank is continuously extruded by a continuous extrusion device. The aluminum rod is scraped to remove the surface oxide scale, cleaned and preheated, and then pressed into the wheel groove of the extrusion wheel by a compacting wheel to establish friction. Driven by the friction, the aluminum material enters the cavity to form a metal fluid, which is extruded and solidified by a mold to obtain the wire blank.

[0018] Compared with the existing technology, the S6 continuous extrusion method has the following differences: the S6 continuous extrusion method has fewer steps, a shorter process, high production efficiency and material utilization rate; an additional step of scraping off the surface oxide scale is added to improve the purity of the aluminum rod blank and the quality of the wire blank is better; friction heat is utilized to eliminate heating and reduce energy consumption.

[0019] Compared with the existing technology, the S6 continuous extrusion step has the following improvements: no heating and pickling are required in the step, no pollutant emissions are generated, and it is green and environmentally friendly; the equipment has a high degree of automation and low operating costs; the equipment is compact, occupies a small area, and requires low investment in equipment and plant construction; the product has uniform performance, high dimensional accuracy, and good finish.

[0020] First, an extrusion process (based on the principle of continuous extruder) can produce wire billets of φ1.6-2.5mm, which are characterized by large deformation (deformation of up to 95%), short process, and low equipment investment cost. Secondly, due to the large torque and low speed of the extrusion wheel of the continuous extruder (the continuous extrusion equipment is specially customized with the manufacturer when purchased. In contrast to the high speed and low torque of the equipment on the market, it has low speed and high torque, but the energy consumption is basically the same). The aluminum rod billets produced by continuous casting can be directly pressed into the wheel groove of the extrusion wheel without annealing, and the solid aluminum material is crushed into a semi-solid state. In general wire billet production, the aluminum rod billets need to be annealed before the continuous extrusion process.

[0021] The aluminum rod is softened and then pressed into the extrusion wheel. After the continuous extrusion process is completed, annealing is performed again, which reduces one annealing process. In addition, this annealing process can achieve intermediate annealing and low-temperature annealing at the same time. This results in a short process route, low equipment investment cost, and low production cost.

[0022] The main improvement of this application is that the continuous extrusion equipment is specially customized to have a low speed of 0-12r / min and high torque according to the continuous extrusion process technology requirements. The speed of this application invention for continuous extrusion of Al-Si-Mg-Sc aluminum rods is 9-10r / min. The continuous extrusion equipment on the market has a high speed, basically 0-30r / min, and low torque. Due to the characteristics of high torque, the aluminum rod billet produced by continuous casting can be pressed into the extrusion wheel to produce wire billets without annealing.

[0023] The continuous extrusion process parameter indicators are rotation speed, extrusion gap, cooling water, and the extrusion speed is determined by preparing wire billets at different rotation speeds. Through the accumulation of data from multiple tests, it is found that the metallographic quality, mechanical properties, and production efficiency of the wire billets prepared at 9-10r / min are relatively excellent. After analysis, it is found that this is the result obtained under the combined action of Al-Si-Mg-Sc element formula, extrusion speed, extrusion gap, and cooling water. If a parameter indicator is changed at random, the above results cannot be obtained.

[0024] According to the embodiments of the present invention, the present invention can be further optimized. The following is the technical solution formed after optimization:

[0025] In one of the preferred embodiments, the casting temperature in S5 ranges from 690°C to 710°C, the crystallization wheel has its own water cooling system, the cooling water temperature ranges from 15°C to 30°C, and the aluminum liquid is cooled and solidified by the crystallization wheel to obtain an aluminum rod blank; preferably, the diameter of the aluminum rod blank is 9.5-10.5 mm.

[0026] In one preferred embodiment, the alloy raw material includes the following components in mass percentage: Si 6.7% to 7.7%, Mg 0.6% to 0.8%, Ti 0.12% to 0.18%, Sc 0.04% to 0.12%, Zr 0.04% to 0.07%, Er 0.04% to 0.07%, Sr 0.04% to 0.07%, Fe ≤ 0.15%, and the rest are Al and other inevitable impurity elements, the content of each element in the inevitable impurity elements is ≤ 0.05%, and the total amount of other inevitable impurity elements is ≤ 0.15%.

[0027] In one preferred embodiment, the electromagnetic stirring frequency in S2 is 20 Hz to 30 Hz.

[0028] The aluminum liquid is made to move irregularly by the emitted traveling wave magnetic field, and the elemental composition is adjusted by pre-furnace analysis to obtain aluminum liquid with uniform elemental composition.

[0029] In one of the preferred embodiments, the temperature range of refining and degassing in S3 is 710°C to 730°C, aluminum strontium alloy is added for modification, and argon is used to blow the refining agent into the aluminum liquid through a rotating rotor for furnace refining. The time range of furnace refining is 20 minutes to 30 minutes, and the hydrogen content in the aluminum melt after refining and degassing is ≤0.1ml / 100gAl.

[0030] In one preferred embodiment, the S7 annealing treatment is to keep the wire billet at a temperature range of 300° C. to 350° C. for 1 to 2 hours, and then keep the wire billet at a temperature range of 200° C. to 250° C. for 3 to 4 hours.

[0031] The annealing process of the national standard brand ZL114A wire billet with similar alloy composition is to keep the temperature at 300℃-400℃ for 2-3 hours. The existing annealing temperature range is relatively large, 300-400℃, which belongs to complete annealing. The annealing temperature range of this application is a temperature range optimized according to the addition of Sc and Zr alloy elements and the arrangement of production process procedures. The first section belongs to intermediate annealing, the purpose is to obtain a balanced and uniform structure, which is 300-350℃. The second section belongs to low-temperature annealing, which eliminates processing residual stress, which is 200-250℃. The purpose is to anneal through the temperature parameters in this range so that its various properties reach the best state.

[0032] In one of the preferred embodiments, the drawing and scraping in S7 is specifically to draw the annealed wire blank to a nearly finished product size, then remove surface scratches and fatigue layer through two consecutive scraping passes, and obtain Al-Si-Mg-Sc aluminum alloy wire through cleaning layer winding.

[0033] In one preferred embodiment, S4 specifically adopts degassing bricks for online degassing and slag removal, and adopts a two-stage filtration system to control the removal rate of inclusions with a particle size greater than 5 μm in the aluminum melt to be greater than 90%.

[0034] Preferably, the diameter of the wire blank in S6 is 2.0-2.7 mm.

[0035] Preferably, the diameter of the Al-Si-Mg-Sc aluminum alloy wire in S7 is 1.2-1.8 mm.

[0036] Preferably, the alloy raw materials in S1 include aluminum ingots, aluminum silicon alloys, aluminum titanium alloys, aluminum erbium alloys, aluminum zirconium alloys, aluminum scandium alloys and magnesium ingots.

[0037] Preferably, after S1 is heated and melted, the element composition is analyzed and adjusted for the first time before the furnace to obtain qualified aluminum liquid.

[0038] Preferably, after S2 electromagnetic stirring, the element composition is analyzed and adjusted for the second time before the furnace to obtain aluminum liquid with uniform element composition.

[0039] Preferably, S3 uses 99.999% Ar gas to fill the aluminum liquid for refining and degassing, and after refining and degassing, the aluminum liquid is allowed to stand and adjust the temperature.

[0040] Preferably, in S5, the aluminum melt is first introduced into a flow control box and then quantitatively introduced into a crystallization wheel.

[0041] The invention also discloses an Al-Si-Mg-Sc aluminum alloy wire prepared according to the preparation method of the Al-Si-Mg-Sc aluminum alloy wire.

[0042] The invention also discloses an Al-Si-Mg-Sc aluminum alloy wire material, which has a tensile strength of ≥340MPa, a yield strength of ≥300MPa and an elongation of ≥8% after T6 heat treatment.

[0043] The chemical composition is evenly distributed, with good room temperature mechanical properties and high temperature stability, and no difference in isotropic properties.

[0044] Al-Si-Mg-Sc completes continuous casting and becomes aluminum rod billet. The aluminum rod structure is mainly composed of α-Al matrix, (α-Al+Si) eutectic, Mg2Si phase, Al3Ti phase and AlSc2Si2 phase, and then enters the continuous extrusion process. Due to the large continuous extrusion deformation, reaching 95%, at a speed of 9-10r / min, with large torque, the cast dendrite structure is severely broken, and the eutectic phase is gradually broken into small and uniform round particles, distributed along the grain elongation direction. Mg2Si, Al3Ti, and AlSc2Si2 are dispersed in the aluminum alloy matrix, thereby effectively pinning grain boundaries and dislocations, preventing the migration and merging of subgrain boundaries in the alloy, and effectively stabilizing the subgrain structure, thereby refining the structure and obtaining a fine and uniformly distributed Al-Si-Mg-Sc aluminum alloy microstructure. In addition, the experiment shows that the crushing and refinement of the Al-Si-Mg-Sc aluminum rod billet structure through continuous extrusion shear deformation is very critical to controlling the excellent terminal product structure.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) The preparation method of Al-Si-Mg-Sc aluminum alloy wire provided in the present application adopts a continuous casting process to directly obtain a wire rod blank from an aluminum melt. The process flow is short, the crystallization inside the rod blank is uniform and refined, there is no element segregation, the surface of the rod blank is smooth, and there are no scratches visible to the naked eye, oxide scale inclusions and other defects.

[0047] (2) The preparation method of Al-Si-Mg-Sc aluminum alloy wire provided in the present application is that the wire rod blank produced by the continuous extrusion process has its structure fully broken after severe shear deformation, and has a dense and fine shear deformed grain structure. The wire rod blank has good drawing processability and only needs one intermediate annealing in the subsequent processing to be drawn and scraped to the finished product size, thereby improving production efficiency and reducing costs.

[0048] (3) The preparation method of the Al-Si-Mg-Sc aluminum alloy wire provided in the present application adopts continuous casting and continuous extrusion technology, the manufacturing process is simple, and the yield rate is ≥80%.

[0049] (4) The Al-Si-Mg-Sc aluminum alloy wire provided in the present application contains 0.04%-0.12% Sc element. The Sc, Zr, and Ti elements work together to refine the grains, thereby reducing structural defects and significantly improving the mechanical properties of the printed body of the Al-Si-Mg-Sc aluminum alloy. DETAILED DESCRIPTION

[0050] The present invention will be described in detail below in conjunction with the embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0051] Example:

[0052] Aluminum ingots, pure magnesium, aluminum silicon alloy, aluminum titanium alloy, aluminum zirconium alloy, aluminum scandium alloy, aluminum erbium alloy, and aluminum strontium alloy were weighed, and alloys were smelted, and continuous casting, continuous extrusion, intermediate annealing, drawing and scraping, cleaning and layer winding, and sample printing were performed to obtain printed parts. Table 1 shows the chemical element contents in each printed part in Examples 1-3.

[0053] Table 1 Chemical element analysis sheet of printed parts of Examples 1-3

[0054]

[0055] The production process of aluminum alloy wire is:

[0056] (1) Aluminum liquid smelting: add aluminum ingots, aluminum silicon alloy, aluminum titanium alloy, aluminum erbium alloy, aluminum zirconium alloy, and aluminum scandium alloy into the medium frequency furnace and heat and melt. The aluminum liquid temperature is 720-730℃, mechanical stirring is carried out for 25 minutes, and the speed is 300r / min. The element composition is adjusted for the first time before the furnace to obtain qualified aluminum liquid;

[0057] (2) Electromagnetic stirring: Turn on the electromagnetic stirring power supply, set the traveling wave frequency to vary from 20 Hz to 30 Hz, and stir the aluminum liquid electromagnetically for 25 minutes. Perform a second analysis and adjustment of the elemental composition before the furnace to obtain aluminum liquid with uniform elemental composition;

[0058] (3) Refining and degassing: The aluminum liquid is transferred into a refining furnace for refining and degassing. 99.999% Ar gas is filled into the aluminum liquid for refining and degassing. The Ar gas flow rate is 18L / min. The refining is performed for 30 minutes. After refining and degassing, the aluminum liquid is allowed to stand and the temperature is adjusted. The hydrogen content in the aluminum melt after treatment is ≤0.1ml / 100g Al.

[0059] (4) Online filtration: A two-stage filtration device is used to perform online degassing, deslagging and filtration on the aluminum melt; and the removal rate of inclusions with a particle size greater than 1 μm in the aluminum melt is controlled to be greater than 90%.

[0060] (5) Continuous casting: The casting temperature ranges from 690°C to 710°C. The crystallization wheel has its own water cooling system. The cooling water temperature ranges from 15°C to 30°C. The aluminum liquid is cooled and solidified by the crystallization wheel. The casting speed is 110-150kg / h to obtain the Φ9.5mm aluminum rod blank. The temperature range of the aluminum rod blank is 350°C to 400°C.

[0061] (6) Continuous extrusion: The wire rod blank is continuously extruded, and the aluminum rod is scraped to remove the surface oxide scale, cleaned and preheated, and then pressed into the wheel groove of the extrusion wheel by a compacting wheel. The speed of the extrusion wheel is 9 rpm, and a wire wire blank with a diameter of 2.7 mm is obtained;

[0062] (7) Intermediate annealing: the wire rod blank is annealed, and the annealing process of the wire rod blank is as follows: heating to 320° C. for 2 hours, keeping at 320° C. for 1.5 hours, cooling to 270° C. for 2 hours, keeping at 270° C. for 3.5 hours, and air cooling after being taken out of the furnace.

[0063] (8) Drawing and scraping: The annealed wire blank is drawn to a nearly finished product size at a speed of 4-6 m / s, and then the surface scratches and fatigue layer are scraped off by two consecutive stripping steps at a speed of 3-5 m / s.

[0064] (9) Cleaning and layer winding: The wire blank is subjected to surface cleaning, chemical coating, and layer winding packaging to obtain the finished Al-Si-Mg-Sc aluminum alloy wire with a diameter of 1.2 mm and a single coil weight of 7 kg.

[0065] The wires prepared in Examples 1, 2, and 3 were printed using CMT arc additive manufacturing equipment, and processed into three groups of test pieces after T6 heat treatment. The mechanical properties of the printed parts were tested in accordance with GB / T 228.1-2021 standard, and the test results are shown in Table 2:

[0066] Table 2 Mechanical properties test results of printed parts

[0067]

[0068]

[0069] Comparative Example:

[0070] Aluminum ingots, pure magnesium, aluminum silicon alloy, aluminum titanium alloy, aluminum zirconium alloy, aluminum erbium alloy, and aluminum strontium alloy were weighed, and alloys were smelted, and continuous casting, continuous extrusion, intermediate annealing, drawing and scraping, cleaning and layer winding, and sample printing were performed to obtain printed parts. Table 3 shows the chemical element contents in each printed part in Comparative Examples 1-3.

[0071] Table 3 Chemical element analysis of the printouts of Comparative Examples 1-3

[0072]

[0073] The production process of aluminum alloy wire is:

[0074] (1) Aluminum liquid smelting: add aluminum ingots, aluminum silicon alloy, aluminum titanium alloy, aluminum erbium alloy, and aluminum zirconium alloy into the medium frequency furnace and heat and melt. The aluminum liquid temperature is 720-730℃, mechanically stirred for 25 minutes, and the speed is 300r / min. The element composition is adjusted for the first time before the furnace to obtain qualified aluminum liquid;

[0075] (2) Electromagnetic stirring: Turn on the electromagnetic stirring power supply, set the traveling wave frequency to vary from 20 Hz to 30 Hz, and stir the aluminum liquid electromagnetically for 25 minutes. Perform a second analysis and adjustment of the elemental composition before the furnace to obtain aluminum liquid with uniform elemental composition;

[0076] (3) Refining and degassing: The aluminum liquid is transferred into a refining furnace for refining and degassing. 99.999% Ar gas is filled into the aluminum liquid for refining and degassing. The Ar gas flow rate is 18L / min. The refining is performed for 30 minutes. After refining and degassing, the aluminum liquid is allowed to stand and the temperature is adjusted. The hydrogen content in the aluminum melt after treatment is ≤0.1ml / 100g Al.

[0077] (4) Online filtration: A two-stage filtration device is used to perform online degassing, deslagging and filtration on the aluminum melt; and the removal rate of inclusions with a particle size greater than 1 μm in the aluminum melt is controlled to be greater than 90%.

[0078] (5) Continuous casting: The casting temperature ranges from 690°C to 710°C. The crystallization wheel has its own water cooling system. The cooling water temperature ranges from 15°C to 30°C. The aluminum liquid is cooled and solidified by the crystallization wheel. The casting speed is 110-150kg / h to obtain the Φ9.5mm aluminum rod blank. The temperature range of the aluminum rod blank is 350°C to 400°C.

[0079] (6) Continuous extrusion: The wire rod blank is continuously extruded, and the aluminum rod is scraped to remove the surface oxide scale, cleaned and preheated, and then pressed into the wheel groove of the extrusion wheel by a compacting wheel. The speed of the extrusion wheel is 9 rpm, and a wire wire blank with a diameter of 2.7 mm is obtained;

[0080] (7) Intermediate annealing: the wire rod blank is annealed, and the annealing process of the wire rod blank is as follows: heating to 320° C. for 2 hours, keeping at 320° C. for 1.5 hours, cooling to 270° C. for 2 hours, keeping at 270° C. for 3.5 hours, and air cooling after being taken out of the furnace.

[0081] (8) Drawing and scraping: The annealed wire blank is drawn to a nearly finished product size at a speed of 4-6 m / s, and then the surface scratches and fatigue layer are scraped off by two consecutive stripping steps at a speed of 3-5 m / s.

[0082] (9) Cleaning and layer winding: The wire blank is subjected to surface cleaning, chemical coating, and layer winding packaging to obtain the finished Al-Si-Mg-Sc aluminum alloy wire with a diameter of 1.2 mm and a single coil weight of 7 kg.

[0083] The wires prepared in Comparative Examples 1, 2, and 3 were printed using CMT arc additive manufacturing equipment and processed into three groups of test pieces after T6 heat treatment. The mechanical properties of the printed parts were tested in accordance with GB / T 228.1-2021 standard, and the test results are shown in Table 4:

[0084] Table 4 Mechanical properties test results of printed parts

[0085] Example Average tensile strength (MPa) Average yield strength (MPa) Average elongation (%) Comparative Example 1 307 258 6.9 Comparative Example 2 301 261 7.3 Comparative Example 3 298 277 8.1

[0086] The contents explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the embodiments made by those skilled in the art fall within the scope defined by the claims attached to the present invention.

Claims

1. A method for preparing Al-Si-Mg-Sc aluminum alloy wire for arc additive manufacturing, characterized in that The following steps are involved: S1. Aluminum liquid smelting: adding alloy raw materials into a medium frequency furnace, heating and melting, stirring and fully melting to obtain aluminum liquid, wherein the alloy raw materials include aluminum, silicon, magnesium and scandium; S2, electromagnetic stirring: Turn on the electromagnetic stirring power supply to electromagnetically stir the aluminum liquid in S1; S3, refining and degassing: the aluminum liquid is refined and degassed; S4, online filtration: online degassing, deslagging and filtering of the aluminum melt; S5, continuous casting: quantitatively introducing the aluminum melt obtained in S4 into a crystallization wheel, cooling and solidifying through the crystallization wheel to obtain an aluminum rod blank; S6, continuous extrusion: the aluminum rod blank obtained in S5 is transferred to a continuous extrusion device, the aluminum rod blank is straightened, the oxide scale is scraped off, the aluminum rod blank is cleaned, and then introduced into the wheel groove of the extrusion wheel for radial extrusion to obtain a wire blank; S7, intermediate annealing: annealing, drawing and scraping the wire blank; S8, cleaning and layer winding: cleaning the surface of the wire blank, coating with a reagent, and layer winding and packaging to obtain a 3D printing wire; Preferably, the rotation speed of the extrusion wheel in the continuous extrusion in S6 is 9-10 rpm; further preferably, a wire blank with a diameter of 2-4 mm is obtained in S6.

2. The method for preparing the Al-Si-Mg-Sc aluminum alloy wire according to claim 1, characterized in that: The casting temperature in S5 ranges from 690°C to 710°C, the crystallization wheel has its own water cooling system, the cooling water temperature ranges from 15°C to 30°C, and the aluminum liquid is cooled and solidified by the crystallization wheel to obtain an aluminum rod blank; preferably, the diameter of the aluminum rod blank is 9.5-10.5 mm.

3. The method for preparing the Al-Si-Mg-Sc aluminum alloy wire according to claim 1, characterized in that: The alloy raw material includes the following components in mass percentage: Si 6.7%-7.7%, Mg 0.6%-0.8%, Ti 0.12%-0.18%, Sc 0.04%-0.12%, Zr 0.04%-0.07%, Er 0.04%-0.07%, Sr 0.04%-0.07%, Fe≤0.15%, and the rest are Al and other inevitable impurity elements, the content of each element in the inevitable impurity elements is ≤0.05%, and the total amount of other inevitable impurity elements is ≤0.15%.

4. The method for preparing the Al-Si-Mg-Sc aluminum alloy wire according to claim 1, characterized in that: The electromagnetic stirring frequency in S2 is 20 Hz to 30 Hz.

5. The method for preparing the Al-Si-Mg-Sc aluminum alloy wire according to claim 1, characterized in that: The temperature range of refining and degassing in S3 is 710°C to 730°C, aluminum strontium alloy is added for modification, and argon is used to blow the refining agent into the aluminum liquid through a rotating rotor for furnace refining. The time range of furnace refining is 20 minutes to 30 minutes, and the hydrogen content in the aluminum melt after refining and degassing is ≤0.1ml / 100g Al.

6. The method for preparing the Al-Si-Mg-Sc aluminum alloy wire according to claim 1, characterized in that: S7 annealing treatment is to keep the wire billet at a temperature range of 300° C. to 350° C. for 1 to 2 hours, and then keep the wire billet at a temperature range of 200° C. to 250° C. for 3 to 4 hours.

7. The method for preparing the Al-Si-Mg-Sc aluminum alloy wire according to claim 1, characterized in that: The drawing and scraping in S7 specifically involves drawing the annealed wire blank to a size close to the finished product, and then removing surface scratches and fatigue layers through two consecutive scraping passes, and then obtaining a cleaning layer. Al-Si-Mg-Sc aluminum alloy wire.

8. The method for preparing the Al-Si-Mg-Sc aluminum alloy wire according to claim 1, characterized in that: S4 specifically adopts degassing bricks for online degassing and slag removal, and adopts a two-stage filtration system to control the removal rate of inclusions with a particle size greater than 5 μm in the aluminum melt to be greater than 90%.

9. An Al-Si-Mg-Sc aluminum alloy wire prepared according to the method for preparing an Al-Si-Mg-Sc aluminum alloy wire according to any one of claims 1 to 8.

10. An Al-Si-Mg-Sc aluminum alloy wire, characterized in that: After T6 heat treatment, the tensile strength is ≥340MPa, the yield strength is ≥300MPa, and the elongation is ≥8%. The chemical composition is evenly distributed, with good room temperature mechanical properties and high temperature stability, and no difference in isotropic properties.

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