Method for recovering metal through rapid continuous casting and extruding severe deformation of EB smelting

Abstract

The invention relates to a method for recovering metal by using EB (electron beam) smelting rapid continuous casting extrusion severe deformation, which comprises the following steps: cleaning and classifying recovered metal reworked materials, respectively proportioning and mixing, adding into an electron beam cold bed furnace for smelting, keeping the temperature of the obtained metal liquid by an electromagnetic pump, and transferring into a subsequent continuous casting extrusion severe plastic deformation device; the severe plastic deformation degree is larger than 2, special structures and defects in the regenerated material are effectively eliminated, after short-process rapid deformation is conducted, after follow-up heat treatment and surface treatment are conducted, regenerated metal is obtained, and then waste parts and machining allowance generated after recovery enter the recycling process of the material again. The metal material can be repeatedly utilized, the whole-process use cost of the high-value material is remarkably reduced, the service performance of the metal material is comprehensively improved, and a large number of resources are saved.

Description

Technical Field

[0001] The invention relates to the field of metal material recycling technology and processing. Background Art

[0002] With the development of technology in the fields of aerospace, petrochemicals and shipbuilding, the demand for metal materials such as aluminum and aluminum alloys, titanium and titanium alloys, high-strength steel and high-temperature alloys has increased dramatically. Currently, more than 60% of titanium alloy processed materials used in the US aviation field have added titanium alloy recycled materials. The material specifications of most aircraft structural main load-bearing components and engine rotating parts clearly stipulate that recycled materials can be used, and corresponding standards have been formed. In order to reduce material costs, a variety of low-cost processing technologies have been increasingly widely used in the production of recycled materials.

[0003] The full name of EB furnace is electron beam cooling furnace. It is the main equipment for smelting recycled materials. Compared with the traditional processing flow, it can be directly processed after one smelting, which can effectively reduce the processing cost and shorten the process flow. Taking titanium alloy and high-temperature alloy as an example, traditional processing requires three VAR smelting or triple smelting processes to eliminate segregation and inclusions, such as the "Preparation Method of High-Strength and Toughness TA31 Titanium Alloy Material" provided by application number CN202210118404.5 and the "Smelting Process of Large-Sized Ingots of Nickel-Based Powder High-Temperature Alloy FGH4096" provided by CN202210287265.9, the process flow is relatively long.

[0004] At present, a series of research has been carried out around the EB furnace, such as the "Nickel-based alloy slab and its preparation method" provided by application number CN202210503939.4 and the "A dual smelting method of EB furnace and VAR furnace for titanium alloy ingots" provided by application number CN202210311452.6. Both processes cannot be produced continuously. At the same time, the EB furnace has a high temperature during the smelting process, which will cause volatilization of low-melting-point metals, resulting in more serious segregation and uneven mechanical properties of the workpiece. In severe cases, it will lead to scrapping and cause serious economic losses.

[0005] From the above description, it can be seen that most titanium waste recycling products are single and can only be used to prepare ingots or billets. Due to the single category and limited shape, there is still a lot of room for optimization in terms of economy and recyclability. It is urgent to further introduce new processes to simplify the production process and expand the space for metal material recycling and processing technology. Summary of the invention

[0006] The purpose of the present invention is to avoid the shortcomings of the prior art and provide a method for recovering metal by using EB smelting, rapid and continuous casting, extrusion and severe deformation.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a method for recovering metal by rapid continuous casting and extrusion with severe deformation using EB smelting, comprising: Step 1: Processing recycled materials: After the recycled metal materials are classified, cleaned and dried, volatile elements are added according to the demand for recycled metals, and they are pressed into blocks according to the proportions and dried; Step 2, smelting: the dried material blocks are sent into an electron beam cooling furnace to be smelted into a melt, the temperature in the molten pool is controlled by an electron gun, and the melt is stirred until a metal liquid with uniform structure and no segregation is obtained; Step 3: Casting and extruding severe plastic deformation: The molten metal is transported into the casting and extruding severe plastic deformation device through an electromagnetic pump for severe deformation. The degree of severe plastic deformation is greater than 2, which is used to effectively eliminate special structures and defects in the recycled material; Step 4: Post-processing: heat treat, homogenize and straighten the metal after severe plastic deformation in casting and extrusion, remove the oxide scale on the surface of the rough product, and then grind and dephosphorize to obtain recycled metal; Step 5: Regeneration cycle: The waste parts and processing residues generated in the above process are sorted and put into the electron beam cooling furnace for recycling.

[0008] Furthermore, in step one, the metal recycled material is metal blocks, scraps or powder.

[0009] Furthermore, in step 1, the cleaning is specifically: When the metal recycled material is titanium and titanium alloy, it is washed with a mixed acid solution of nitric acid and hydrofluoric acid for 30 to 40 minutes, rinsed with water and then dried at a temperature of 60 to 80°C; When the metal recycled material is aluminum and aluminum alloy, it is washed with nitric acid for 20-40 minutes, rinsed with water and dried at 40-50°C; When the metal recycled material is a high-temperature alloy, it is washed with a mixed solution of hydrochloric acid, hydrofluoric acid and hydrogen peroxide for 20 to 40 minutes, rinsed with water and then dried at 60 to 80°C.

[0010] Furthermore, in step 2, the electron beam cooling furnace is melted at least once, and a plurality of electron guns are used to meet the energy demand for melting. At the same time, at least one electron gun is used for melting and molten pool insulation.

[0011] Furthermore, in step 2, the device used for stirring is an electromagnetic pump or a vibration stirring device; the stirring current of the electromagnetic pump is adjusted in real time according to the magnetism and state of the metal material.

[0012] Furthermore, in the step three, when the molten metal is transported by the electromagnetic pump into the pipeline in the casting and extrusion severe plastic deformation device, an induction coil is used to stir and keep the melt warm to ensure that the molten metal is in a flowing state and still maintain a uniform structure of the molten metal without segregation.

[0013] Furthermore, in step 3, the degree of severe plastic deformation is specifically: When the metal recycled material is titanium alloy or high-strength alloy, the degree of severe plastic deformation is greater than 2.5; When the metal recycled material is a high-temperature alloy, the degree of severe plastic deformation is greater than 2.0; when the metal recycled material is an aluminum alloy, the degree of severe plastic deformation is greater than 3.5.

[0014] Furthermore, in step 4, When the metal recycled material is titanium and titanium alloy, the heat treatment is specifically to keep it at 700-980°C for 60-120 minutes, then air-cool it, then heat it to 450-800°C for 240-480 minutes, then air-cool it; When the metal recycled material is aluminum and aluminum alloy, the heat treatment is specifically as follows: keep the temperature at 300°C to 700°C for 60min to 120min, cool it to 200 to 400°C with the furnace, and then take it out for air cooling; When the metal recycled material is a high-temperature alloy, the heat treatment is specifically: keeping it at 950°C~1200°C for 1h~12h, then air cooling it, and then heating it to 600~800°C and keeping it at 6h~12h.

[0015] Furthermore, in step 4, the oxide scale on the surface of the crude product is removed by shot peening, specifically: When the metal recycled material is titanium and titanium alloy or high temperature alloy, the shot peening abrasive is cast iron shot or cast steel shot with a diameter less than 2mm; When the metal recycled material is aluminum and aluminum alloy, the shot peening abrasive is ceramic shot with a diameter less than 2 mm.

[0016] Furthermore, in step three, the metal recycled materials are processed into crude products such as rods, wires, tubes or profiles after severe casting, extrusion and severe plastic deformation, so as to obtain corresponding recycled metal products after step four.

[0017] The beneficial effects of the present invention are: 1. The present invention classifies titanium, aluminum, high-strength and high-temperature alloy waste materials and then performs proportioning and briquetting. The prepared material blocks are dried and then melted to obtain recycled materials for rapid, continuous, short-process casting, extrusion and severe plastic deformation processing, which can achieve 100% recovery of high-value aviation materials such as titanium, aluminum, high-strength and high-temperature alloys, and improve the utilization rate of metal materials; 2. The process of the present invention is controllable and adjustable, and the prepared recycled material has balanced organization, fine grains, and excellent mechanical properties, and can effectively eliminate harmful organizations, structures and defects unique to recycled materials.

[0018] 3. The present invention combines EB smelting with cast extrusion severe plastic deformation process, which has no special requirements on the form, composition and size of the recycled materials, short process cycle and low energy consumption. It is a new high-value metal material recycling process with low production cost in the whole process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a process flow chart of the present invention; Figure 2 Schematic diagram of stirring and transporting involved in step 2 of the present invention; Figure 3 It is a schematic diagram of step 2-step 3 of the present invention.

[0020] In the figure: 1. inductor coil, 2. electron beam cooling furnace molten pool, 3. heat transport pipe, 4. electron gun, 5. electromagnetic pump, 6. severe plastic deformation device, 7. mold, 8. product. DETAILED DESCRIPTION

[0021] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0022] Example 1: Figure 1 As shown, a method for recovering metal by rapid continuous casting and extrusion with severe deformation using EB smelting, comprising: Step 1: Processing recycled materials: After the recycled metal materials are classified, cleaned and dried, volatile elements are added according to the demand for recycled metals, and the materials are pressed into blocks according to the proportions and dried; the recycled metal materials are blocks, scraps or powders of metals; When the metal recycled material is titanium and titanium alloy, it is washed with a mixed acid solution of nitric acid and hydrofluoric acid for 30-40 minutes, rinsed with water and dried at 60-80°C; Step 2, smelting: the dried material blocks are sent into an electron beam cooling furnace to be smelted into a melt, the temperature in the molten pool is controlled by an electron gun, and the melt is stirred until a metal liquid with uniform structure and no segregation is obtained; The electron beam cold hearth furnace is used for melting at least once, and multiple electron guns are used to meet the energy demand for melting. At the same time, at least one electron gun is used for melting and molten pool insulation.

[0023] The device used for stirring is an electromagnetic pump or a vibration stirring device; the stirring current of the electromagnetic pump is adjusted in real time according to the magnetism and state of the metal material.

[0024] Step 3: Casting and extruding severe plastic deformation: The molten metal is transported into the casting and extruding severe plastic deformation device through an electromagnetic pump for severe deformation. The severe plastic deformation degree is greater than 2.5, which is used to effectively eliminate special structures and defects in the recycled material; In the pipeline where the molten metal is transported by the electromagnetic pump into the casting and extrusion severe plastic deformation device, an induction coil is used to stir and keep the melt warm to ensure that the molten metal is in a flowing state and still maintains a uniform structure without segregation.

[0025] Step 4: Post-processing: heat treat, homogenize and straighten the metal after severe plastic deformation in casting and extrusion, remove the oxide scale on the surface of the rough product, and then grind and dephosphorize to obtain recycled metal; Specifically, the heat treatment is to keep it at 700-980°C for 60-120 minutes, then air-cool it, then heat it to 450-800°C for 240-480 minutes, and then air-cool it; the shot peening abrasive is cast iron shot or cast steel shot with a diameter of less than 2 mm.

[0026] Step 5: Regeneration cycle: The waste parts and processing residues generated in the above process are sorted and put into the electron beam cooling furnace for recycling.

[0027] Embodiment 2: Same as Embodiment 1, except that, The specific cleaning in step 1 is as follows: if the metal recycled material is aluminum and aluminum alloy, wash it with nitric acid for 20-40 minutes, rinse it with water and then dry it at 40-50°C; In step 3, the metal recycled material is aluminum alloy, and the degree of severe plastic deformation is greater than 3.5.

[0028] In step 4, the metal recycled materials are aluminum and aluminum alloys, and the specific heat treatment is: after keeping warm at 300°C~700°C for 60min~120min, cool to 200~400°C with the furnace and then take out and air cool; the shot peening abrasive is ceramic balls with a diameter of less than 2mm.

[0029] Embodiment 3: Same as Embodiment 1, except that: The cleaning in step 1 is as follows: if the metal recycled material is a high-temperature alloy, it is washed with a mixed solution of hydrochloric acid, hydrofluoric acid and hydrogen peroxide for 20 to 40 minutes, rinsed with water and then dried at 60 to 80°C.

[0030] In step 3, the metal recycled material is a high temperature alloy, and the degree of severe plastic deformation is greater than 2.0; In step 4, the metal recycled material is a high temperature alloy, and the specific heat treatment is: keep it at 950°C~1200°C for 1h~12h, then air cool it, and then heat it to 600~800°C and keep it for 6h~12h; the shot peening abrasive is cast iron shot or cast steel shot with a diameter less than 2mm; Example 4: The same as Example 1, except that in step 3, the metal recycled material is processed into a crude product of rods, wires, tubes or profiles after severe casting, extrusion and severe plastic deformation, so as to obtain the corresponding recycled metal product after step 4.

[0031] In order to further illustrate the technical scheme and technical effects of the present invention, the following specific examples are provided. The metal scraps used in the specific embodiments are all derived from the scraps, trimmings and scrapped materials generated during the processing of plates, bars, forgings, castings, etc., as well as disassembled parts, physical and chemical materials, etc. Specific embodiment 1: like Figure 2-3 As shown, a method for recovering metal by using EB smelting, rapid continuous casting, extrusion and severe deformation, the specific steps are as follows: Step 1, processing recycled materials: pickling the received titanium alloy with a mixed acid solution of nitric acid and hydrofluoric acid for 30 to 40 minutes. Pickling is a conventional technique in the art. The specific pickling solution concentration is determined according to the received material form and surface state. After pickling, rinse with water; the drying temperature is 60 to 80°C; an X-ray component analyzer is used to determine the composition of the recycled material, and the mixing ratio is calculated according to the nominal chemical composition of the titanium alloy to be prepared; The raw materials include block-shaped recycled materials and titanium shells used to wrap the blocks, with a total mass of 3,000 kg, of which 94.13% are TC4 titanium alloy recycled materials and 5.87% are pure aluminum residues. The sorted metal materials are supplemented with volatile elements according to the needs of the finished products. 2,823.9 kg of TC4 titanium alloy recycled materials and 176.1 kg of aluminum recycled materials are weighed and pressed into blocks.

[0033] Step 2, smelting: see Figure 2-3 , the dried material blocks are sent to the EB furnace through the conveyor device for smelting once, and the temperature in the molten pool is controlled by an electron gun. The number of electron guns is 7, which are set according to the smelting energy requirements, of which 6 electron guns are used for smelting and 1 is used for smelting and molten pool insulation. The melt is introduced into the electromagnetic pump and stirred to obtain a metal liquid with uniform structure and no segregation. The stirring current is 200~500 A; during the transportation and transfer process, the inductor coil 1 is wrapped on the heat transport pipe 3 to stir and keep the melt warm.

[0034] Step 3, cast extrusion severe plastic deformation: the molten metal is introduced into the cast extrusion severe plastic deformation device 6, and after severe deformation, the crude product of TC4 titanium alloy recycled rod is obtained in one step, the deformation amount per pass is 60%, the extrusion rate is 100 mm / s, and the cumulative deformation degree of the cycle is greater than 2.5.

[0035] Step 4, matching post-processing: heat-treat the obtained TC4 recycled titanium alloy bar crude product, specifically: keep at 900°C for 60 minutes and then air-cool, keep at 650°C for 240 minutes and then air-cool; then perform homogenization treatment, straightening and shaping. Then use shot peening to remove the oxide scale produced on the surface after heat treatment, and the shot peening abrasive is cast iron shot with a diameter of <2mm; then perform grinding, dephosphorization and cutting to obtain TC4 titanium alloy recycled bar.

[0036] Step 5, Regeneration cycle: The waste parts and processing residues generated during the production process enter the cycle again, and after classification and cleaning, they are pressed into blocks and put into the EB furnace.

[0037] The mechanical properties of the TC4 titanium alloy recycled rod were tested, and the mechanical properties comparison results between the original titanium alloy and the recycled titanium alloy are shown in Table 1. Table 1

[0038] It can be seen from the table that the tensile strength, yield strength and maximum elongation of the recycled metal are all improved, and the regeneration effect is good. Specific embodiment 2: A method for recovering metal by using EB smelting, rapid continuous casting, extrusion and severe deformation, the specific steps are as follows: Step 1, processing recycled materials: pickle the received high-temperature alloy with a mixed solution of hydrochloric acid, hydrofluoric acid and hydrogen peroxide for 30 to 40 minutes. Pickling is a conventional technique in the art. The specific pickling solution concentration is determined according to the received material form and surface state. Rinse with water after pickling; the drying temperature is 60 to 80 ° C. Use an X-ray component analyzer to determine the composition of the recycled material. Calculate the mixing ratio according to the nominal chemical composition of the required high-temperature alloy; the raw materials include block recycled materials and titanium shells used to wrap the blocks, with a total mass of 4000 kg, including 99.5% GH4169 high-temperature alloy recycled materials, a small amount of aluminum beans, and Ni powder. The classified metal materials are supplemented with volatile elements according to the needs of the finished products. 3980 kg of GH4169 alloy recycled materials, 15 kg of aluminum beans, and 5 kg of nickel powder are weighed, and the metal recycled materials are pressed into blocks.

[0040] Step 2, smelting: see Figure 2-3, the dried material blocks are sent to the EB furnace through the conveyor device for smelting once, and the temperature in the molten pool is controlled by an electron gun. The number of electron guns is 7, which are set according to the smelting energy requirements, of which 6 are used for smelting and 1 is used for smelting and molten pool insulation. The melt is introduced into the electromagnetic pump and stirred to obtain a metal liquid with uniform structure and no segregation. The stirring current is 400~600 A; during the transportation and transfer process, the inductor coil 1 is wrapped on the heat transport pipe 3 to stir and keep the melt warm.

[0041] Step 3, cast extrusion severe plastic deformation: the molten metal is introduced into the cast extrusion severe plastic deformation device 6, and after severe deformation, the GH4169 high-temperature alloy recycled rod rough product is obtained in one step, the pass deformation amount is 40%, the extrusion rate is 60mm / s, and the cyclic cumulative deformation degree is greater than 2.0.

[0042] Step 4, matching post-processing: heat-treat the crude GH4169 high-temperature alloy recycled bar, specifically: keep at 1020°C for 60 minutes and then air-cool, keep at 720°C for 480 minutes and then furnace-cool to 620°C and keep at 480 minutes and then air-cool; then perform homogenization, straightening and shaping. Shot peening is used to remove the oxide scale produced on the surface after heat treatment, and the shot peening abrasive is cast steel shot with a diameter of <2mm; then perform grinding, dephosphorization and cutting to obtain GH4169 high-temperature alloy recycled bar.

[0043] Step 5, Regeneration cycle: The waste parts and processing residues generated during the production process enter the cycle again, and after classification and cleaning, they are pressed into blocks and put into the EB furnace.

[0044] The mechanical properties of the recycled GH4169 high-temperature alloy rod were tested, and the mechanical properties comparison results of the original GH4169 and the recycled GH4169 are shown in Table 2. Table 2

[0045] It can be seen from the table that the tensile strength, yield strength and maximum elongation of the recycled metal are all improved, and the regeneration effect is good.

[0046] The following description is only an example of a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and improved concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for recovering metals by rapid continuous casting and extrusion with severe deformation using EB smelting, characterized in that: include: Step 1: Processing recycled materials: After the recycled metal materials are classified, cleaned and dried, volatile elements are added according to the demand for recycled metals, and they are pressed into blocks according to the proportions and dried; Step 2, smelting: the dried material blocks are sent into an electron beam cooling furnace to be smelted into a melt, the temperature in the molten pool is controlled by an electron gun, and the melt is stirred until a metal liquid with uniform structure and no segregation is obtained; Step 3: Casting and extruding severe plastic deformation: The molten metal is transported into the casting and extruding severe plastic deformation device through an electromagnetic pump for severe deformation. The degree of severe plastic deformation is greater than 2, which is used to effectively eliminate special structures and defects in the recycled material; Step 4: Post-processing: heat treat, homogenize and straighten the metal after severe plastic deformation in casting and extrusion, remove the oxide scale on the surface of the rough product, and then grind and dephosphorize to obtain recycled metal; Step 5: Regeneration cycle: The waste parts and processing residues generated in the above process are sorted and put into the electron beam cooling furnace for recycling.

2. The method for recovering metal by rapid continuous casting and extrusion with severe deformation using EB smelting as claimed in claim 1, characterized in that: In step 1, the metal recycled material is metal blocks, scraps or powder.

3. The method for recovering metal by rapid continuous casting and extrusion with severe deformation using EB smelting as claimed in claim 1, characterized in that: In step 1, the cleaning is specifically: When the metal recycled material is titanium and titanium alloy, it is washed with a mixed acid solution of nitric acid and hydrofluoric acid for 30 to 40 minutes, rinsed with water and then dried at a temperature of 60 to 80°C; When the metal recycled material is aluminum and aluminum alloy, it is washed with nitric acid for 20-40 minutes, rinsed with water and dried at 40-50°C; When the metal recycled material is a high-temperature alloy, it is washed with a mixed solution of hydrochloric acid, hydrofluoric acid and hydrogen peroxide for 20 to 40 minutes, rinsed with water and then dried at 60 to 80°C.

4. The method for recovering metal by rapid continuous casting and extrusion with severe deformation using EB smelting as claimed in claim 1, characterized in that: In step 2, the electron beam cold hearth furnace is melted at least once, and there are multiple electron guns to meet the energy demand for melting. At the same time, at least one electron gun is used for melting and molten pool insulation.

5. The method for recovering metals by rapid continuous casting and extrusion with severe deformation using EB smelting as claimed in claim 1, characterized in that: In step 2, the device used for stirring is an electromagnetic pump or a vibration stirring device; the stirring current of the electromagnetic pump is adjusted in real time according to the magnetism and state of the metal material.

6. The method for recovering metals by rapid continuous casting and extrusion with severe deformation using EB smelting as claimed in claim 1, characterized in that: In the step three, when the molten metal is transported by the electromagnetic pump into the pipeline in the casting and extrusion severe plastic deformation device, an induction coil is used to stir and keep the melt warm to ensure that the molten metal is in a flowing state and still maintains a uniform structure of the molten metal without segregation.

7. The method for recovering metals by rapid continuous casting and extrusion with severe deformation by EB smelting as claimed in claim 1, characterized in that: In step 3, the degree of severe plastic deformation is specifically: When the metal recycled material is titanium alloy or high-strength alloy, the degree of severe plastic deformation is greater than 2.5; When the metal recycled material is a high-temperature alloy, the degree of severe plastic deformation is greater than 2.0; when the metal recycled material is an aluminum alloy, the degree of severe plastic deformation is greater than 3.

5.

8. The method for recovering metals by rapid continuous casting and extrusion with severe deformation by EB smelting as claimed in claim 1, characterized in that: In step four, When the metal recycled material is titanium and titanium alloy, the heat treatment is specifically to keep it at 700-980°C for 60-120 minutes, then air-cool it, then heat it to 450-800°C for 240-480 minutes, then air-cool it; When the metal recycled material is aluminum and aluminum alloy, the heat treatment is specifically as follows: keep the temperature at 300°C to 700°C for 60min to 120min, cool it to 200 to 400°C with the furnace, and then take it out for air cooling; When the metal recycled material is a high-temperature alloy, the heat treatment is specifically: keeping it at 950°C~1200°C for 1h~12h, then air cooling it, and then heating it to 600~800°C and keeping it at 6h~12h.

9. The method for recovering metals by rapid continuous casting and extrusion with severe deformation using EB smelting as claimed in claim 1, characterized in that: In step 4, the oxide scale on the surface of the crude product is removed by shot peening, specifically: When the metal recycled material is titanium and titanium alloy or high temperature alloy, the shot peening abrasive is cast iron shot or cast steel shot with a diameter less than 2mm; When the metal recycled material is aluminum and aluminum alloy, the shot peening abrasive is ceramic shot with a diameter less than 2 mm.

10. The method for recovering metals by rapid continuous casting and extrusion with severe deformation by EB smelting as claimed in any one of claims 1 to 9, characterized in that: In step three, the metal recycled materials are processed into crude products such as rods, wires, tubes or profiles after severe casting, extrusion and severe plastic deformation, so as to obtain corresponding recycled metal products after step four.

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