Method for preparing large-size ultrahigh-strength aluminum alloy round ingot through spray forming

Abstract

The invention provides a method for preparing a large-size ultrahigh-strength aluminum alloy round ingot through spray forming, which comprises the following steps of: (A) determining the components of an aluminum alloy, and calculating the dosage of raw materials according to the determined components of the aluminum alloy; (B) the raw materials in the step (A) are placed in an induction furnace to be intensively smelted, and an aluminum alloy slag removal covering agent is used for covering; (C) after the aluminum alloy in the step (B) is fully and intensively molten, adding a deslagging agent into the molten aluminum alloy, carrying out electromagnetic stirring, carrying out primary deslagging and degassing on the liquid metal, standing, and filtering; and (D), the liquid metal filtered in the step (C) is poured into at least one preheated tundish to be transferred, the structure is reasonable, the mode that concentrated spraying, tundish transferring, continuous production and melt melting and spraying deposition can be conducted at the same time is adopted, the production efficiency, the productivity and the equipment utilization rate are greatly improved, and the production cost is saved.

Description

Technical Field

[0001] The present application relates to the field of aluminum alloy preparation technology, and specifically, to a method for preparing large-scale ultra-high-strength aluminum alloy ingots by using injection molding. Background Art

[0002] Aluminum alloy is the most widely used lightweight metal material in the national defense industry. How to reduce density, improve strength and toughness in material modification, and how to improve corrosion resistance, weldability and formability in application technology are the current research focuses at home and abroad, especially the development of ultra-high-strength aluminum alloys and aluminum-lithium alloys, which can replace conventional aluminum alloys and even steel materials with not too high load-bearing capacity with high specific strength, and the weight reduction can reach more than 20% to 40%. Ultra-high-strength aluminum alloys often have a high alloy content, and there are technical bottlenecks in the semi-continuous casting process of ingots. The chemical composition of the ingots is severely macroscopically segregated, the structure is coarse, the thermal stress is large, the ingot cracking tendency is prominent, and the yield rate is very low.

[0003] The emergence of spray forming technology has provided a new idea for the development of large-scale ultra-high strength aluminum alloy materials. The alloy grains of spray forming technology are significantly refined, and various macro and micro segregations are suppressed. It can effectively control the internal thermal cracking of the deposited blank during solidification. At the same time, due to the accelerated solidification rate, the supersaturation of various alloy elements in the deposited blank is increased, which can make the precipitation of various deposited phases in the subsequent heat treatment process more sufficient and obtain better mechanical properties. Spray forming concentrates the large-scale advantages of casting technology and the high alloying advantages of powder metallurgy. At the same time, the effect of refining the organization is more significant than microalloying, electromagnetic stirring casting, etc. Therefore, spray forming is the best process technology for developing ultra-high strength aluminum alloys.

[0004] In the prior art, in the existing spray deposition production process, after the preparation of an ingot is completed, the residual melt in the ladle, the intermediate ladle, the transfer trough, and the liquid guide tube quickly oxidizes and solidifies to form residue, and it is necessary to wait for the corresponding equipment to cool down and then carry out slag cleaning in preparation for the next batch of production. Only "one batch per day" can be produced, with low production efficiency, low equipment utilization, low production capacity, and high cost. Therefore, there is an urgent need for a method for preparing large-scale ultra-high strength aluminum alloy round ingots using spray forming to solve the above-mentioned problems. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of this application is to provide a method for preparing large-scale ultra-high strength aluminum alloy ingots by spray forming, so as to solve the problems raised in the above background technology.

[0006] In order to achieve the above object, the present application provides a method for preparing large-scale ultra-high strength aluminum alloy ingots by spray forming, comprising the following steps:

[0007] Step (A) determining the composition of the aluminum alloy, and calculating the amount of raw materials based on the determined aluminum alloy composition;

[0008] Step (B) placing the raw materials in step (A) in an induction furnace for centralized smelting, and covering them with an aluminum alloy slag removal covering agent;

[0009] Step (C) After the aluminum alloy in step (B) is fully and centrally melted, a slag remover is added thereto, electromagnetic stirring is performed, and the liquid metal is preliminarily slag removed and degassed, and then the liquid metal is allowed to stand and then filtered;

[0010] Step (D) pouring the liquid metal filtered in step (C) into at least one preheated tundish for transfer, adding a slag remover, and electromagnetic stirring for secondary refining, slag removal, and degassing, while adding a refining agent into the tundish, and pressing the refining agent into the liquid metal 20-40 cm below the liquid surface with a pressure cover, and moving the pressure cover up and down to generate a large number of bubbles and scum on the surface of the liquid metal, and then removing the scum on the surface of the liquid metal;

[0011] Step (E) the liquid metal from which the scum is removed in step (D) is allowed to stand for filtration, and then poured into a plurality of leaking crucibles through a pipette tank to wait for injection;

[0012] Step (F) delivers the liquid metal in the plurality of crucibles to the corresponding spray forming equipment and atomizes it in an inert atmosphere to form a particle jet, and deposits the particle jet onto a substrate at high speed to solidify into a large-sized, ultra-high-strength aluminum alloy ingot.

[0013] Preferably, the composition of the aluminum alloy in step (A) is as follows in weight percentage: Cu 0.8-1.2%, Mg 2.0-3.0%, Zr 0.08-0.3%, Zn 11.0-12.0%, Mn≤0.25%, Ti≤0.05%, Fe≤0.12%, Si≤0.1%, Cr≤0.2%, V≤0.05%, other impurities individually ≤0.05%, total ≤0.15%, and the balance is Al.

[0014] Preferably, the melting temperature of the induction furnace in step (B) is 730°C-780°C.

[0015] Preferably, the standing time in step (C) and step (E) is 20-40 min.

[0016] Preferably, the inert atmosphere in step (F) is nitrogen.

[0017] Preferably, the spray deposition process parameters of the spray forming equipment in step (F) are: spray angle 10-50°, atomization pressure 0.5-1.3 MPa, atomization temperature 600°C-950°C, receiving plate rotation speed 20-60rpm, receiving plate descending speed 1-6mm / s, and receiving distance 400-850mm.

[0018] Preferably, in step (F), the deposition chamber of the spray forming on the spray forming equipment is protected by nitrogen and the nitrogen pressure is maintained at 0.6 to 1.5 atmospheres during the spraying process.

[0019] Preferably, the large-sized, ultra-high-strength aluminum alloy ingot formed by spray solidification in step (F) has a diameter of ≥800 mm and a weight of ≥3 tons.

[0020] According to a method of preparing large-sized ultra-high-strength aluminum alloy ingots by spray forming in the present application, by adopting centralized aluminum, centralized spraying, ladle transfer, and continuous production, melt melting and spray deposition can be carried out simultaneously, so that the production capacity of a single spray forming equipment can be increased from the current domestic and foreign production efficiency of "one furnace per day" to "multiple furnaces in one shift", greatly improving production efficiency, production capacity, equipment utilization, and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0022] Figure 1 The present invention is a flow chart of a method for preparing large-sized ultra-high-strength aluminum alloy ingots by spray forming according to one embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the technical means, creative features, objectives and effects achieved by this application easy to understand, this application is further explained below in conjunction with specific implementation methods.

[0024] like Figure 1 As shown, the present application provides a technical solution: a method for preparing large-scale ultra-high-strength aluminum alloy ingots by spray forming, comprising the following steps:

[0025] Step (A) determining the composition of the aluminum alloy, and calculating the amount of raw materials based on the determined aluminum alloy composition;

[0026] Step (B) placing the raw materials in step (A) in an induction furnace for centralized smelting, and covering them with an aluminum alloy slag removal covering agent;

[0027] Step (C) After the aluminum alloy in step (B) is fully and centrally melted, a slag remover is added thereto, electromagnetic stirring is performed, and the liquid metal is preliminarily slag removed and degassed, and then the liquid metal is allowed to stand and then filtered;

[0028] Step (D) pouring the liquid metal filtered in step (C) into at least one preheated tundish for transfer, adding a slag remover, and electromagnetic stirring for secondary refining, slag removal, and degassing, while adding a refining agent into the tundish, and pressing the refining agent into the liquid metal 20-40 cm below the liquid surface with a pressure cover, and moving the pressure cover up and down to generate a large number of bubbles and scum on the surface of the liquid metal, and then removing the scum on the surface of the liquid metal;

[0029] Step (E) the liquid metal from which the scum is removed in step (D) is allowed to stand for filtration, and then poured into a plurality of leaking crucibles through a pipette tank to wait for injection;

[0030] Step (F) delivers the liquid metal in the plurality of crucibles to the corresponding spray forming equipment and atomizes it in an inert atmosphere to form a particle jet, and deposits the particle jet onto a substrate at high speed to solidify into a large-sized, ultra-high-strength aluminum alloy ingot.

[0031] Preferably, the composition of the aluminum alloy in step (A) is as follows in weight percentage: Cu 0.8-1.2%, Mg 2.0-3.0%, Zr 0.08-0.3%, Zn 11.0-12.0%, Mn≤0.25%, Ti≤0.05%, Fe≤0.12%, Si≤0.1%, Cr≤0.2%, V≤0.05%, other impurities individually ≤0.05%, total ≤0.15%, and the balance is Al.

[0032] Preferably, the melting temperature of the induction furnace in step (B) is 730°C-780°C.

[0033] Preferably, the standing time in step (C) and step (E) is 20-40 min.

[0034] Preferably, the inert atmosphere in step (F) is nitrogen.

[0035] Preferably, the spray deposition process parameters of the spray forming equipment in step (F) are: spray angle 10-50°, atomization pressure 0.5-1.3 MPa, atomization temperature 600°C-950°C, receiving plate rotation speed 20-60rpm, receiving plate descending speed 1-6mm / s, and receiving distance 400-850mm.

[0036] Preferably, in step (F), the deposition chamber of the spray forming on the spray forming equipment is protected by nitrogen and the nitrogen pressure is maintained at 0.6 to 1.5 atmospheres during the spraying process.

[0037] Preferably, the large-sized, ultra-high-strength aluminum alloy ingot formed by spray solidification in step (F) has a diameter of ≥800 mm and a weight of ≥3 tons.

[0038] A specific embodiment is introduced below according to a method of preparing large-sized ultra-high strength aluminum alloy ingots by spray forming according to the present invention.

[0039] Embodiment 1: Step (A1) determines the composition of the aluminum alloy, and calculates the amount of raw materials based on the determined aluminum alloy composition, wherein the composition of the aluminum alloy is as follows in weight percentage: Cu 1.0%, Mg 2.5%, Zr 0.16%, Zn 11.5%, Mn ≤ 0.25%, Ti ≤ 0.05%, Fe ≤ 0.12%, Si ≤ 0.1%, Cr ≤ 0.2%, V ≤ 0.05%, other impurities individually ≤ 0.05%, total ≤ 0.15%, and the balance is Al;

[0040] Step (B1) placing the raw materials in step (A1) in an induction furnace for centralized smelting, and covering them with an aluminum alloy slag removal covering agent, wherein the smelting temperature is 750° C.;

[0041] Step (C1) After the aluminum alloy in step (B1) is fully and centrally melted, a slag remover is added thereto, electromagnetic stirring is performed, and the liquid metal is preliminarily deslaged and degassed, and then the liquid metal is allowed to stand for 30 minutes and then filtered;

[0042] Step (D1) pouring the liquid metal filtered in step (C1) into at least one preheated tundish for transfer, adding a slag remover, and electromagnetic stirring for secondary refining, slag removal, and degassing, while adding a refining agent into the tundish, and pressing the refining agent into the 30 cm below the liquid metal surface with a pressure cover, and moving the pressure cover up and down to generate a large number of bubbles and scum on the surface of the liquid metal, and then removing the scum on the surface of the liquid metal;

[0043] Step (E1) The liquid metal from which the scum is removed in step (D1) is allowed to stand for 30 minutes and then filtered, and then poured into a plurality of leaking crucibles through a pipette tank to wait for injection;

[0044] Step (F1) delivers the liquid metal inside the multiple leaky crucibles to the corresponding connected injection molding equipment and atomizes it in an inert atmosphere to form a particle jet stream, and adjusts the injection angle of the injection molding equipment to 30°, the atomization pressure to 1MPa, the atomization temperature to 800°C, the receiving plate rotation speed to 40rpm, the receiving plate descending speed to 4mm / s, and the receiving distance to 600mm to control the flow rate of the particle jet stream and the size of the final injection ingot, and make the particle jet stream deposited on the substrate at a high speed, solidified to form a large-size, ultra-high-strength aluminum alloy ingot, wherein the injection molding deposition chamber on the injection molding equipment is protected by nitrogen and the nitrogen pressure is maintained at 1 atmosphere during the injection process.

[0045] Embodiment 2: Step (A2) determines the composition of the aluminum alloy, and calculates the amount of raw materials based on the determined aluminum alloy composition, wherein the composition of the aluminum alloy is as follows in weight percentage: Cu 0.8%, Mg 2.0%, Zr 0.08%, Zn 11.0%, Mn ≤ 0.25%, Ti ≤ 0.05%, Fe ≤ 0.12%, Si ≤ 0.1%, Cr ≤ 0.2%, V ≤ 0.05%, other impurities individually ≤ 0.05%, total ≤ 0.15%, and the balance is Al;

[0046] Step (B2) placing the raw materials in step (A2) in an induction furnace for centralized smelting, and covering them with an aluminum alloy slag removal covering agent, wherein the smelting temperature is 730° C.;

[0047] Step (C2) After the aluminum alloy in step (B2) is fully and centrally melted, a slag remover is added thereto, electromagnetic stirring is performed, and the liquid metal is preliminarily deslaged and degassed, and then the liquid metal is allowed to stand for 20 minutes and then filtered;

[0048] Step (D2) pouring the liquid metal filtered in step (C2) into at least one preheated tundish for transfer, adding a slag remover, and electromagnetic stirring to perform secondary refining, slag removal, and degassing, while adding a refining agent into the tundish, and using a pressure cover to press the refining agent into the liquid metal 20 cm below the liquid surface, and moving the pressure cover up and down to generate a large number of bubbles and scum on the surface of the liquid metal, and then removing the scum on the surface of the liquid metal;

[0049] Step (E2) The liquid metal from which the scum is removed in step (D2) is allowed to stand for 20 minutes and then filtered, and then poured into a plurality of leaking crucibles through a pipette tank to wait for injection;

[0050] Step (F2) delivers the liquid metal inside the multiple leaky crucibles to the corresponding connected injection molding equipment and atomizes it in an inert atmosphere to form a particle jet stream, and adjusts the injection angle of the injection molding equipment to 10°, the atomization pressure to 0.5MPa, the atomization temperature to 600°C, the receiving plate rotation speed to 30rpm, the receiving plate descending speed to 2mm / s, and the receiving distance to 450mm to control the flow rate of the particle jet stream and the size of the final injection ingot, and make the particle jet stream deposited on the substrate at a high speed, solidified to form a large-size, ultra-high strength aluminum alloy ingot, wherein the injection molding deposition chamber on the injection molding equipment is protected by nitrogen and the nitrogen pressure is maintained at 0.6 atmospheres during the injection process.

[0051] Embodiment 3: Step (A3) determines the composition of the aluminum alloy, and calculates the amount of raw materials based on the determined aluminum alloy composition, wherein the composition of the aluminum alloy is as follows in weight percentage: Cu 1.2%, Mg 3.0%, Zr 0.3%, Zn 12.0%, Mn ≤ 0.25%, Ti ≤ 0.05%, Fe ≤ 0.12%, Si ≤ 0.1%, Cr ≤ 0.2%, V ≤ 0.05%, other impurities individually ≤ 0.05%, total ≤ 0.15%, and the balance is Al;

[0052] Step (B3) placing the raw materials in step (A3) in an induction furnace for centralized smelting, and covering them with an aluminum alloy slag removal covering agent, wherein the smelting temperature is 780° C.;

[0053] Step (C3) After the aluminum alloy in step (B3) is fully and centrally melted, a slag remover is added thereto, electromagnetic stirring is performed, and the liquid metal is preliminarily deslaged and degassed, and then the liquid metal is allowed to stand for 40 minutes and then filtered;

[0054] Step (D3) pouring the liquid metal filtered in step (C3) into at least one preheated tundish for transfer, adding a slag remover, and electromagnetic stirring for secondary refining, slag removal, and degassing, while adding a refining agent into the tundish, and pressing the refining agent into the 35 cm below the liquid metal surface with a pressure cover, and moving the pressure cover up and down to generate a large number of bubbles and scum on the surface of the liquid metal, and then removing the scum on the surface of the liquid metal;

[0055] Step (E3) The liquid metal from which the scum is removed in step (D3) is allowed to stand for 40 minutes and then filtered, and then poured into a plurality of leaking crucibles through a pipette tank to wait for injection;

[0056] Step (F3) delivers the liquid metal inside the multiple leaky crucibles to the corresponding connected injection molding equipment and atomizes it in an inert atmosphere to form a particle jet stream, and adjusts the injection angle of the injection molding equipment to 50°, the atomization pressure to 1.2MPa, the atomization temperature to 900°C, the receiving tray rotation speed to 50rpm, the receiving tray descending speed to 5mm / s, and the receiving distance to 800mm to control the flow rate of the particle jet stream and the size of the final injection ingot, and make the particle jet stream deposited on the substrate at a high speed, solidified to form a large-size, ultra-high strength aluminum alloy ingot, wherein the injection molding deposition chamber on the injection molding equipment is protected by nitrogen and the nitrogen pressure is maintained at 1.2 atmospheres during the injection process.

[0057] According to the present application, a method for preparing large-sized ultra-high strength aluminum alloy ingots by using spray forming adopts centralized aluminum, centralized spraying, tundish transfer, and continuous production. Melt melting and spray deposition can be carried out simultaneously, so that the production capacity of a single spray forming equipment can be increased from the current domestic and foreign production efficiency of "one furnace per day" to "multiple furnaces in one shift", which greatly improves production efficiency, production capacity, equipment utilization, and reduces production costs.

[0058] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing large-size ultra-high strength aluminum alloy ingots by spray forming, characterized in that: The following steps are involved: Step (A) determining the composition of the aluminum alloy, and calculating the amount of raw materials based on the determined aluminum alloy composition; Step (B) placing the raw materials in step (A) in an induction furnace for centralized smelting, and covering them with an aluminum alloy slag removal covering agent; Step (C) After the aluminum alloy in step (B) is fully and centrally melted, a slag remover is added thereto, electromagnetic stirring is performed, and the liquid metal is preliminarily slag removed and degassed, and then the liquid metal is allowed to stand and then filtered; Step (D) pouring the liquid metal filtered in step (C) into at least one preheated tundish for transfer, adding a slag remover, and electromagnetic stirring for secondary refining, slag removal, and degassing, while adding a refining agent into the tundish, and pressing the refining agent into the liquid metal 20-40 cm below the liquid surface with a pressure cover, and moving the pressure cover up and down to generate a large number of bubbles and scum on the surface of the liquid metal, and then removing the scum on the surface of the liquid metal; Step (E) the liquid metal from which the scum is removed in step (D) is allowed to stand for filtration, and then poured into a plurality of leaking crucibles through a pipette tank to wait for injection; Step (F) delivers the liquid metal in the plurality of crucibles to the corresponding spray forming equipment and atomizes it in an inert atmosphere to form a particle jet, and deposits the particle jet onto a substrate at high speed to solidify into a large-sized, ultra-high-strength aluminum alloy ingot.

2. The method for preparing large-sized ultra-high strength aluminum alloy ingots by spray forming according to claim 1, characterized in that: The components of the aluminum alloy in the step (A) are as follows in weight percentage: Cu 0.8-1.2%, Mg 2.0-3.0%, Zr 0.08-0.3%, Zn 11.0-12.0%, Mn≤0.25%, Ti≤0.05%, Fe≤0.12%, Si≤0.1%, Cr≤0.2%, V≤0.05%, other impurities are individually ≤0.05%, the total amount is ≤0.15%, and the balance is Al.

3. The method for preparing large-sized ultra-high strength aluminum alloy ingots by spray forming according to claim 1, characterized in that: The melting temperature of the induction furnace in the step (B) is 730°C-780°C.

4. The method for preparing large-sized ultra-high strength aluminum alloy ingots by spray forming according to claim 1, characterized in that: The standing time in step (C) and step (E) is 20-40 minutes.

5. The method for preparing large-size ultra-high strength aluminum alloy ingots by spray forming according to claim 1, characterized in that: The inert atmosphere in the step (F) is nitrogen.

6. The method for preparing large-sized ultra-high strength aluminum alloy ingots by spray forming according to claim 1, characterized in that: The spray deposition process parameters of the spray forming equipment in the step (F) are: spray angle 10-50°, atomization pressure 0.5-1.3 MPa, atomization temperature 600°C-950°C, receiving tray rotation speed 20-60rpm, receiving tray descending speed 1-6mm / s, and receiving distance 400-850mm.

7. The method for preparing large-sized ultra-high strength aluminum alloy ingots by spray forming according to claim 1, characterized in that: In the step (F), the deposition chamber of the spray forming equipment is protected by nitrogen and the nitrogen pressure is maintained at 0.6 to 1.5 atmospheres during the spraying process.

8. The method for preparing large-size ultra-high strength aluminum alloy round ingots by spray forming according to claim 1, characterized in that: The large-sized, ultra-high-strength aluminum alloy ingot formed by spray solidification in the step (F) has a diameter of ≥800 mm and a weight of ≥3 tons.

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