Preparation method of large-size spray-formed aluminum-magnesium-scandium alloy

Abstract

The invention relates to a preparation method of a large-size spray-formed aluminum-magnesium-scandium alloy. The preparation method comprises the following steps: step 1, preparing raw materials according to the mass percent of alloy components; 2, the proportioned raw materials are placed in an induction furnace to be smelted; step 3, after the raw materials are completely molten, adding a slag remover and carrying out electromagnetic stirring; 4, the liquid metal is subjected to standing, filtered and transferred to a preheated tundish, then a deslagging agent is added, electromagnetic stirring is carried out, and secondary refining deslagging and degassing treatment is carried out; the refining agent and the melt are fully reacted through reciprocating motion of the pressing cover; 5, standing and filtering the liquid metal subjected to secondary refining, and injecting the liquid metal into a ladle leakage crucible to wait for injection; and 6, under inert atmosphere protection, liquid metal is subjected to atomization treatment to form a particle jet flow, the particle jet flow is deposited on a base body at a high speed and solidified, a large-specification aluminum-magnesium-scandium alloy ingot blank material is obtained, the alloy is free of macrosegregation, fine equiaxed crystal grains are generated, the ingot casting yield is increased, and the alloy has good machinability.

Description

Technical Field

[0001] The present invention relates to the technical field of application of nonferrous metal aluminum alloys, and in particular to a method for preparing a large-scale spray-formed aluminum-magnesium-scandium alloy. Background Art

[0002] High-performance structural materials are the core foundation supporting my country's national defense, military, aerospace and other major equipment. The preparation and application of high-performance metal materials are of great significance to the development of my country's aerospace industry.

[0003] With the development of the aerospace industry, the demand for medium-strength weldable structural materials is increasing. Traditional Al-Mg alloys have two significant shortcomings: first, they cannot be strengthened by heat treatment, resulting in low strength; second, they are easily softened by heat after cold working. Soviet researchers discovered that adding trace amounts of Sc to aluminum alloys can significantly improve their properties. They developed a series of Al-Mg-Sc alloys based on Al-Mg alloys. These alloys not only maintain the excellent corrosion resistance and weldability of Al-Mg alloys, but also increase strength and overcome the disadvantage of easy softening by heat. Currently, research on Al-Mg-Sc alloys has attracted the attention of domestic materials researchers and has become a hot topic in domestic research on new aluminum alloys.

[0004] 5B70 aluminum-magnesium-scandium alloy does not require heat treatment strengthening and can achieve high-precision manufacturing of ultra-weak rigid structures. It has high strength, good plasticity and toughness, good corrosion resistance, high temperature resistance, good forming performance, high forming precision, and a welding strength of up to 90%. It is a new material that improves product performance and effectively reduces structural weight, and has significant application advantages.

[0005] Currently, the conventional process for preparing aluminum-magnesium-scB alloys is traditional casting. However, scandium has a low solubility in the melt, making it prone to segregation during casting, severely impacting the alloy's compositional uniformity and yield. Furthermore, 5B70 alloys contain a relatively high Mg content. Excessive β-phase precipitation along grain boundaries can easily become a source of cracks during subsequent plastic working, hindering processing. Spray forming, however, effectively addresses this elemental segregation issue in 5B70 alloys. Under the rapid solidification conditions of spray forming, the alloy exhibits no macrosegregation and produces fine, equiaxed grains. This not only addresses the low ingot yield issue but also ensures excellent workability during subsequent hot working. Furthermore, the spray forming process is not limited by melt volume, and its uniform, fine structure is inherited by the final product, creating a strengthening effect that provides a certain margin for performance in various product types, particularly those with large thicknesses. During the spray forming process, small droplets fully release dissolved hydrogen from the melt, resulting in superior solid hydrogen content in the finished product, effectively ensuring the airtightness of thin-walled components. Therefore, compared with traditional casting methods for producing 5B70 aluminum-magnesium-scandium alloy, the spray forming process offers significant advantages, making research into the preparation technology of this material a must. Summary of the Invention

[0006] In response to the above problems, the present invention discloses a method for preparing a large-scale spray-formed aluminum-magnesium-scandium alloy. The large-scale aluminum-magnesium-scandium alloy material is prepared by spray-forming technology to obtain an industrialized material with performance that meets the requirements.

[0007] The specific technical solutions are as follows:

[0008] A method for preparing a large-scale spray-formed aluminum-magnesium-scandium alloy comprises the following steps:

[0009] S1. Prepare raw materials: Prepare raw materials according to the mass percentage of alloy components. The aluminum ingot component is preferably Al 99.95 high-purity aluminum ingot;

[0010] S2. Melting temperature control: Place the proportioned raw materials in an induction furnace for melting treatment, and cover the surface of the melt with an aluminum alloy slag removal covering agent;

[0011] S3. Primary smelting and impurity removal: After the raw materials are completely melted, a slag remover is added to the melt and electromagnetic stirring is performed to complete the initial slag removal and degassing of the liquid metal;

[0012] S4, pressure hood refining: The liquid metal after primary refining is allowed to stand and filter, and then transferred to a preheated tundish. A slag remover is added again and electromagnetic stirring is performed for secondary refining, slag removal, and degassing. At the same time, a refining agent is added to the tundish and a pressure hood device is used to press the refining agent into the aluminum melt to a depth of 35 cm below the liquid surface. The reciprocating up and down motion of the pressure hood promotes a full reaction between the refining agent and the melt. After bubbles and scum are formed on the surface of the melt, the scum is removed.

[0013] S5, liquid transfer to wait for spraying: the liquid metal after secondary refinement is allowed to stand and filter, and then injected into the crucible through the pipette trough to wait for spraying;

[0014] S6. Spray forming: Under the protection of an inert atmosphere, the liquid metal is atomized to form a particle jet stream. The spray angle, atomization pressure, atomization temperature, receiving disk rotation speed, receiving disk descent rate and receiving disk spacing parameters are adjusted to control the flow rate of the particle jet stream and the ingot forming size. Ultimately, the particle jet stream is deposited on the substrate at a high speed and solidified to obtain a large-sized aluminum-magnesium-scandium alloy ingot material.

[0015] S7. Cooling and decompression: After the large-sized aluminum-magnesium-scandium alloy ingot to be spray-formed is naturally cooled to 200°C, residual stress relief treatment is performed, and then the ingot is taken out and air-cooled to room temperature.

[0016] After spray cooling and forming, a uniform cylindrical spray ingot is obtained with a diameter of about 800 mm, a height of 2000 mm, a weight of about 2.7 tons, a density of 98%, and a grain size of ≤50 μm.

[0017] Preferably, in step 1, the composition and weight percentage of the aluminum-magnesium-scandium alloy are:

[0018] Mg: 5.5%~6.5%, Mn: 0.15%~0.4%, Zr: 0.1%~0.2%, Sc: 0.2%~0.4%, Ti: 0.02%~0.05%, Cu≤0.05%, Fe≤0.2%, Si≤0.1%, Zn≤0.05%, and the balance is Al.

[0019] Preferably, the melting temperature of the induction furnace in step S2 is 730°C to 790°C.

[0020] Preferably, the standing time in steps S4 and S5 is 30 minutes.

[0021] Preferably, in step S6, the atomization pressure is 0.5-1.3 MPa; and the atomization temperature is 600° C.-950° C.

[0022] Preferably, in step S6, the receiving tray rotation speed is 20-60 rpm; the receiving tray descending speed is 1-6 mm / s; and the receiving distance of the receiving tray is 400-850 mm.

[0023] Preferably, in step S6, the deposition chamber of the spray forming is protected by nitrogen and the nitrogen pressure is maintained at 0.6 to 1.5 atmospheres during the spraying process.

[0024] The beneficial effects of the present invention are embodied in:

[0025] The present invention adopts a spray forming process to effectively solve the element segregation problem of the 5B70 alloy. Under the process conditions of rapid solidification of spray forming, the alloy has no macroscopic segregation, and at the same time, fine equiaxed grains can be generated, which not only improves the yield rate of the ingot, but also makes the alloy have good processability during the subsequent hot working process. At the same time, the spray forming process is not limited by the volume of the melt, so that the uniform and fine structure is inherited to the final product, forming a fine product strengthening effect, and a certain margin is brought to the performance of the thick material. In addition, during the spray forming process, the small molten droplets fully release the dissolved hydrogen in the melt, and the solid hydrogen content index in the finished product is more excellent, which effectively guarantees the airtightness of thin-walled components. Therefore, compared with the traditional casting method for producing 5B70 aluminum-magnesium-scandium alloy materials, the spray forming process has more significant advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention provides a flow chart of a method for preparing a large-scale spray-formed aluminum-magnesium-scandium alloy.

[0027] Figure 2 This is a real picture of the ingot after injection molding in the present invention. DETAILED DESCRIPTION

[0028] In order to make the technical solution of the present invention clearer and more specific, the present invention is further described below with reference to the accompanying drawings. Any equivalent replacement of the technical features of the technical solution of the present invention and any solution derived by conventional reasoning shall fall within the scope of protection of the present invention.

[0029] Please see the attached Figure 1-2 This embodiment provides a method for preparing a large-scale spray-formed aluminum-magnesium-scandium alloy, comprising the following steps:

[0030] (1) Prepare raw materials: Prepare raw materials according to the mass percentage of alloy components: main alloying elements Mg (5.5-6.5%), Mn (0.15-0.4%), Zr (0.1-0.2%), Sc (0.2-0.4%), Ti (0.02-0.05%), Cu (≤0.05%), Fe (≤0.2%), Si (≤0.1%), Zn (≤0.05%), and the balance is Al. The aluminum ingot Al is preferably an Al 99.95 high-purity aluminum ingot.

[0031] (2) Melting temperature control: The alloy components according to the alloy formula ratio are melted in an induction furnace, covered with aluminum alloy slag removal covering agent, and the melting temperature is controlled at 730℃~790℃.

[0032] (3) Primary refining and impurity removal: After the metal raw materials are completely melted, a certain amount of slag remover is added to the melt and electromagnetic stirring is performed to perform preliminary slag removal and degassing of the liquid metal. The slag remover is preferably C2Cl6.

[0033] (4) Press-cover refining: The liquid metal after primary refining is allowed to stand for 30 minutes and then filtered. The liquid metal is then transferred to a preheated tundish, and a certain amount of slag remover is added again. Electromagnetic stirring is performed to carry out secondary refining, slag removal and degassing. At the same time, a refining agent (model HGJ-1A) is added to the tundish. The refining agent is then pressed into the aluminum melt at a depth of 35 cm below the liquid surface using a press-cover device. The reciprocating up and down motion of the press-cover promotes a full reaction between the refining agent and the melt. After bubbles and slag are generated on the surface of the melt, the slag is removed.

[0034] (5) Liquid transfer for spraying: The liquid metal after secondary refining is filtered and then injected into the crucible through the pipette to wait for spraying.

[0035] (6) Spray forming: Under the protection of inert atmosphere nitrogen, the liquid metal is atomized to form a particle jet flow, and the nozzle spray angle, atomization pressure, atomization temperature, receiving disk speed, receiving disk descent rate and receiving disk spacing parameters are adjusted to control the flow rate of the particle jet flow and the ingot forming size. Finally, the particle jet flow is deposited on the substrate at a high speed and solidified to obtain large-sized aluminum-magnesium-scandium alloy ingot material.

[0036] The spray deposition process parameters are: atomization pressure of 0.5 to 1.3 MPa, atomization temperature of 600°C to 950°C, receiving tray rotation speed of 20 to 60 rpm, receiving tray descent speed of 1 to 6 mm / s, and receiving distance of 400 to 850 mm. The spray deposition chamber is protected by nitrogen, and the nitrogen pressure is maintained at 0.6 to 1.5 atmospheres during the spraying process.

[0037] (7) Cooling and decompression: After the large-sized aluminum-magnesium-scandium alloy ingot to be spray-formed is naturally cooled to 200°C, residual stress relief treatment is performed, and then the ingot is taken out and air-cooled to room temperature to obtain a uniform cylindrical spray ingot with a diameter of about 800 mm, a height of 2000 mm, a weight of about 2.7 tons, a density of 98%, and a grain size of ≤50 μm.

[0038] The spray forming process effectively addresses the elemental segregation problem in the 5B70 alloy. Under the rapid solidification conditions of spray forming, the alloy exhibits no macrosegregation while simultaneously producing fine equiaxed grains. This not only improves the ingot yield rate but also ensures excellent workability during subsequent hot working. Furthermore, the spray forming process is unrestricted by melt volume, allowing for the inheritance of a uniform, fine structure into the final product, resulting in a strengthening effect for fine products and a margin in the performance of thicker materials. Furthermore, the small molten droplets during spray forming fully release dissolved hydrogen from the melt, resulting in a superior solid hydrogen content in the finished product, effectively ensuring the airtightness of thin-walled components. Therefore, compared to traditional casting methods for producing 5B70 aluminum-magnesium-scandium alloy, the spray forming process offers significant advantages.

[0039] Example 1

[0040] (1) Prepare raw materials: Prepare the raw materials according to the mass percentage of the alloy components: main alloying elements Mg (6%), Mn (0.275%), Zr (0.15%), Sc (0.3%), Ti (0.035%), Cu (≤0.05%), Fe (≤0.2%), Si (≤0.1%), Zn (≤0.05%), and the balance is Al. The aluminum ingot Al is preferably an Al 99.95 high-purity aluminum ingot.

[0041] (2) Melting temperature control: The alloy components according to the alloy formula ratio are melted in an induction furnace, covered with an aluminum alloy slag removal covering agent, and the melting temperature is controlled at 760°C.

[0042] (3) Primary smelting and impurity removal: After the metal raw materials are completely melted, a certain amount of slag remover is added to the melt and electromagnetic stirring is performed to perform preliminary slag removal and degassing of the liquid metal.

[0043] (4) Press-cover refining: The liquid metal after primary refining is allowed to stand for 30 minutes and then filtered. The liquid metal is then transferred to a preheated tundish, and a certain amount of slag remover is added again. Electromagnetic stirring is performed to carry out secondary refining, slag removal and degassing. At the same time, a refining agent is added to the tundish, and the refining agent is pressed into the aluminum melt at a depth of 35 cm below the liquid surface using a press-cover device. The reciprocating up and down motion of the press-cover promotes the full reaction between the refining agent and the melt. After bubbles and slag are generated on the surface of the melt, the slag is removed.

[0044] (5) Liquid transfer for spraying: The liquid metal after secondary refining is filtered and then injected into the crucible through the pipette to wait for spraying.

[0045] (6) Spray forming: Under the protection of inert atmosphere nitrogen, the liquid metal is atomized to form a particle jet flow, and the nozzle spray angle, atomization pressure, atomization temperature, receiving disk speed, receiving disk descent rate and receiving disk spacing parameters are adjusted to control the flow rate of the particle jet flow and the ingot forming size. Finally, the particle jet flow is deposited on the substrate at a high speed and solidified to obtain large-sized aluminum-magnesium-scandium alloy ingot material.

[0046] The spray deposition process parameters are: atomization pressure of 0.8 MPa, atomization temperature of 710°C, receiving tray rotation speed of 45 rpm, receiving tray descent speed of 3 mm / s, and receiving distance of 800 mm. The spray deposition chamber is protected by nitrogen, and the nitrogen pressure is maintained at 0.9 atmospheres during the spraying process.

[0047] Cooling and pressure relief: After the large-sized aluminum-magnesium-scandium alloy ingot to be spray-formed is naturally cooled to 200°C, residual stress relief treatment is carried out, and then the ingot is taken out and air-cooled to room temperature to obtain a uniform cylindrical spray ingot.

[0048] Example 2

[0049] (1) Prepare raw materials: Prepare raw materials according to the mass percentage of alloy components: main alloying elements Mg (5.5%), Mn (0.15%), Zr (0.1%), Sc (0.2%), Ti (0.02%), Cu (≤0.05%), Fe (≤0.2%), Si (≤0.1%), Zn (≤0.05%), and the balance is Al. The aluminum ingot Al is preferably an Al 99.95 high-purity aluminum ingot.

[0050] (2) Melting temperature control: The alloy components according to the alloy formula ratio are melted in an induction furnace, covered with an aluminum alloy slag removal covering agent, and the melting temperature is controlled at 730°C.

[0051] (3) Primary smelting and impurity removal: After the metal raw materials are completely melted, a certain amount of slag remover is added to the melt and electromagnetic stirring is performed to perform preliminary slag removal and degassing of the liquid metal.

[0052] (4) Press-cover refining: The liquid metal after primary refining is allowed to stand for 30 minutes and then filtered. The liquid metal is then transferred to a preheated tundish, and a certain amount of slag remover is added again. Electromagnetic stirring is performed to carry out secondary refining, slag removal and degassing. At the same time, a refining agent is added to the tundish, and the refining agent is pressed into the aluminum melt at a depth of 35 cm below the liquid surface using a press-cover device. The reciprocating up and down motion of the press-cover promotes the full reaction between the refining agent and the melt. After bubbles and slag are generated on the surface of the melt, the slag is removed.

[0053] (5) Liquid transfer for spraying: The liquid metal after secondary refining is filtered and then injected into the crucible through the pipette to wait for spraying.

[0054] (6) Spray forming: Under the protection of inert atmosphere nitrogen, the liquid metal is atomized to form a particle jet flow, and the nozzle spray angle, atomization pressure, atomization temperature, receiving disk speed, receiving disk descent rate and receiving disk spacing parameters are adjusted to control the flow rate of the particle jet flow and the ingot forming size. Finally, the particle jet flow is deposited on the substrate at a high speed and solidified to obtain large-sized aluminum-magnesium-scandium alloy ingot material.

[0055] The spray deposition process parameters are: atomization pressure of 0.5 MPa, atomization temperature of 600°C, receiving tray rotation speed of 30 rpm, receiving tray descent speed of 2 mm / s, and receiving distance of 450 mm. The spray deposition chamber is protected by nitrogen, and the nitrogen pressure is maintained at 0.6 atmospheres during the spraying process.

[0056] Cooling and pressure relief: After the large-sized aluminum-magnesium-scandium alloy ingot to be spray-formed is naturally cooled to 200°C, residual stress relief treatment is carried out, and then the ingot is taken out and air-cooled to room temperature to obtain a uniform cylindrical spray ingot.

[0057] Example 3

[0058] (1) Prepare raw materials: Prepare raw materials according to the mass percentage of alloy components: main alloying elements Mg (6.5%), Mn (0.4%), Zr (0.2%), Sc (0.4%), Ti (0.05%), Cu (≤0.05%), Fe (≤0.2%), Si (≤0.1%), Zn (≤0.05%), and the balance is Al. The aluminum ingot Al is preferably an Al 99.95 high-purity aluminum ingot.

[0059] (2) Melting temperature control: The alloy components according to the alloy formula ratio are melted in an induction furnace, covered with an aluminum alloy slag removal covering agent, and the melting temperature is controlled at 790°C.

[0060] (3) Primary smelting and impurity removal: After the metal raw materials are completely melted, a certain amount of slag remover is added to the melt and electromagnetic stirring is performed to perform preliminary slag removal and degassing of the liquid metal.

[0061] (4) Press-cover refining: The liquid metal after primary refining is allowed to stand for 30 minutes and then filtered. The liquid metal is then transferred to a preheated tundish, and a certain amount of slag remover is added again. Electromagnetic stirring is performed to carry out secondary refining, slag removal and degassing. At the same time, a refining agent is added to the tundish, and the refining agent is pressed into the aluminum melt at a depth of 35 cm below the liquid surface using a press-cover device. The reciprocating up and down motion of the press-cover promotes the full reaction between the refining agent and the melt. After bubbles and slag are generated on the surface of the melt, the slag is removed.

[0062] (5) Liquid transfer for spraying: The liquid metal after secondary refining is filtered and then injected into the crucible through the pipette to wait for spraying.

[0063] (6) Spray forming: Under the protection of inert atmosphere nitrogen, the liquid metal is atomized to form a particle jet flow, and the nozzle spray angle, atomization pressure, atomization temperature, receiving disk speed, receiving disk descent rate and receiving disk spacing parameters are adjusted to control the flow rate of the particle jet flow and the ingot forming size. Finally, the particle jet flow is deposited on the substrate at a high speed and solidified to obtain large-sized aluminum-magnesium-scandium alloy ingot material.

[0064] The spray deposition process parameters are: atomization pressure of 1.2 MPa, atomization temperature of 900°C, receiving tray rotation speed of 60 rpm, receiving tray descent speed of 4 mm / s, and receiving distance of 600 mm. The spray deposition chamber is protected by nitrogen, and the nitrogen pressure is maintained at 1.2 atmospheres during the spraying process.

[0065] Cooling and pressure relief: After the large-sized aluminum-magnesium-scandium alloy ingot to be spray-formed is naturally cooled to 200°C, residual stress relief treatment is carried out, and then the ingot is taken out and air-cooled to room temperature to obtain a uniform cylindrical spray ingot.

[0066] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a large-scale spray-formed aluminum-magnesium-scandium alloy, comprising the following steps: S1. Prepare raw materials: Prepare raw materials according to the mass percentage of alloy components. The aluminum ingot component is preferably Al 99.95 high-purity aluminum ingot; S2. Melting temperature control: Place the proportioned raw materials in an induction furnace for melting, and use an aluminum alloy slag removal covering agent to cover the melt surface; S3. Primary smelting and impurity removal: After the raw materials are completely melted, a slag remover is added to the melt and electromagnetic stirring is performed to complete the initial slag removal and degassing of the liquid metal; S4, pressure hood refining: The liquid metal after primary refining is allowed to stand and filter, and then transferred to a preheated tundish. A slag remover is added again and electromagnetic stirring is performed for secondary refining, slag removal, and degassing. At the same time, a refining agent is added to the tundish and a pressure hood device is used to press the refining agent into the aluminum melt to a depth of 35 cm below the liquid surface. The reciprocating up and down motion of the pressure hood promotes a full reaction between the refining agent and the melt. After bubbles and scum are formed on the surface of the melt, the scum is removed. S5, liquid transfer to wait for spraying: the liquid metal after secondary refinement is allowed to stand and filter, and then injected into the crucible through the pipette to wait for spraying; S6. Spray forming: Under the protection of an inert atmosphere, the liquid metal is atomized to form a particle jet stream. The spray angle, atomization pressure, atomization temperature, receiving disk rotation speed, receiving disk descent rate and receiving disk spacing parameters are adjusted to control the flow rate of the particle jet stream and the ingot forming size. Ultimately, the particle jet stream is deposited on the substrate at a high speed and solidified to obtain a large-sized aluminum-magnesium-scandium alloy ingot material. S7. Cooling and decompression: After the large-sized aluminum-magnesium-scandium alloy ingot to be spray-formed is naturally cooled to 200°C, residual stress relief treatment is performed, and then the ingot is taken out and air-cooled to room temperature.

2. The method for preparing a large-scale spray-formed aluminum-magnesium-scandium alloy according to claim 1, characterized in that: In step 1, the composition and weight percentage of the aluminum-magnesium-scandium alloy are: Mg: 5.5%~6.5%, Mn: 0.15%~0.4%, Zr: 0.1%~0.2%, Sc: 0.2%~0.4%, Ti: 0.02%~0.05%, Cu≤0.05%, Fe≤0.2%, Si≤0.1%, Zn≤0.05%, and the balance is Al.

3. The method for preparing a large-scale spray-formed aluminum-magnesium-scandium alloy according to claim 1, wherein: The melting temperature of the induction furnace in step S2 is 730° C. to 790° C.

4. The method for preparing a large-scale spray-formed aluminum-magnesium-scandium alloy according to claim 1, wherein: The standing time in steps S4 and S5 is 30 minutes.

5. The method for preparing a large-scale spray-formed aluminum-magnesium-scandium alloy according to claim 1, wherein: In step S6, the atomization pressure is 0.5-1.3 MPa; the atomization temperature is 600° C.-950° C.

6. The method for preparing a large-scale spray-formed aluminum-magnesium-scandium alloy according to claim 1, wherein: In step S6, the receiving tray rotates at a speed of 20 to 60 rpm; the receiving tray descends at a speed of 1 to 6 mm / s; and the receiving distance of the receiving tray is 400 to 850 mm.

7. The method for preparing a large-scale spray-formed aluminum-magnesium-scandium alloy according to claim 1, wherein: In step S6, the deposition chamber of the spray forming is protected by nitrogen and the nitrogen pressure is maintained at 0.6 to 1.5 atmospheres during the spraying process.

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