Method for recycling of metals by eb melting rapid continuous casting extrusion severe deformation

Abstract

The present application relates to a kind of methods for recycling metal by EB smelting rapid continuous casting extrusion severe deformation, after washing and classification of recycled metal regenerative material, respectively, proportioning and mixing, adding electron beam cold bed furnace and smelting, the molten metal obtained is transferred into subsequent continuous casting extrusion severe plastic deformation device by electromagnetic pump heat preservation, the degree of severe plastic deformation is greater than 2, and special organization and defects in regenerative material are effectively eliminated, after short process rapid deformation, after subsequent heat treatment and surface treatment, regenerative metal is obtained, and then the scrap and machining allowance generated are recycled into the material recycling process again.The present application can recycle metal materials, significantly reduce the total process use cost of high value materials, comprehensively improve the service performance of metal materials, and save a lot of resources.

Description

Technical Field

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

[0002] With the development of technologies in aerospace, petrochemical, and shipbuilding industries, the demand for metallic materials such as aluminum and aluminum alloys, titanium and titanium alloys, high-strength steel, and high-temperature alloys has increased dramatically. Currently, over 60% of the titanium alloy processed materials used in the US aerospace industry incorporate recycled titanium alloy materials. Most aircraft structural load-bearing components and engine rotating parts have material specifications that explicitly allow the use of recycled materials, and corresponding standards have been established. To reduce material costs, various low-cost processing techniques are increasingly being used in the production of recycled materials.

[0003] The EB furnace, short for electron beam cold hearth furnace, is currently the main equipment for smelting recycled materials. Compared with traditional processing methods, it has the advantage of allowing direct processing after a single smelting, effectively reducing processing costs and shortening the process flow. Taking titanium alloys and high-temperature alloys as examples, traditional processing requires three VAR smelting or triple smelting processes to eliminate segregation and inclusions, such as the technologies in "A Preparation Method of High-Strength and Tough TA31 Titanium Alloy Material" (application number CN202210118404.5) and "Smelting Process of Large-Size Ingots of Nickel-Based Powder High-Temperature Alloy FGH4096" (application number CN202210287265.9), which involve a relatively long process flow.

[0004] Currently, a series of studies have been conducted on EB furnaces, such as the process methods of "Nickel-based alloy slabs and their preparation methods" provided by application number CN202210503939.4 and "A dual melting method of EB furnace and VAR furnace for titanium alloy ingots" provided by application number CN202210311452.6. Neither of these processes can produce continuously. At the same time, the EB furnace has a high temperature during the melting process, which will cause the volatilization of low melting point metals, resulting in more serious segregation. The mechanical properties of the workpiece are uneven, which can lead to scrapping in severe cases and cause serious economic losses.

[0005] As can be seen from the above description, most titanium scrap recycling products are limited to a single type, only suitable for preparing ingots or billets. Due to the limited product variety and shapes, there is still considerable room for improvement in terms of economic efficiency and recyclability. There is an urgent need to introduce new processes to simplify production procedures and expand the scope of metal material recycling and processing technologies. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for recovering metals by rapidly and continuously casting and extruding under severe deformation using EB melting.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for recovering metal using rapid continuous casting and extrusion with severe deformation via EB melting, comprising:

[0008] Step 1: Processing recycled materials: After sorting, cleaning, and drying the recycled metal materials, add volatile elements according to the needs of the recycled metal, press them into blocks according to the formula and dry them.

[0009] Step 2, Melting: The dried material blocks are fed into an electron beam cold hearth furnace to be melted into a molten body. The temperature in the molten pool is controlled by an electron gun, and the molten body is stirred until a metal liquid with a uniform structure and no segregation is obtained.

[0010] Step 3, Intense Plastic Deformation in Casting and Extrusion: Molten metal is pumped into the intense plastic deformation device for intense deformation using an electromagnetic pump. The degree of intense plastic deformation is greater than 2, which is used to effectively eliminate special structures and defects in recycled materials.

[0011] Step 4, Post-processing: After the metal undergoes severe plastic deformation by casting and extrusion, it is subjected to heat treatment, homogenization treatment and straightening in sequence. The oxide scale on the surface of the rough product is removed, and then it is ground and dephosphorized to obtain recycled metal.

[0012] Step 5, Regeneration and Recycling: After sorting and processing the waste parts and processing residues generated in the above process, put them into the electron beam cold hearth furnace for recycling.

[0013] Furthermore, in step one, the recycled metal material is metal in blocks, scraps, or powder.

[0014] Furthermore, in step one, the cleaning specifically includes:

[0015] 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 a temperature of 60-80°C.

[0016] When the metal recycled material is aluminum and aluminum alloy, it is washed with nitric acid for 20 to 40 minutes, rinsed with water, and dried at a temperature of 40 to 50°C.

[0017] When the recycled metal 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 a temperature of 60 to 80°C.

[0018] Furthermore, in step two, the electron beam cold hearth furnace is used for melting at least once, and there are multiple electron guns to meet the energy requirements of melting. At the same time, at least one electron gun is used for melting and heat preservation of the molten pool.

[0019] Furthermore, in step 2, the stirring device is an electromagnetic pump or a vibratory stirring device; the stirring current of the electromagnetic pump is adjusted in real time according to the magnetism and state of the metal material.

[0020] Furthermore, in step three, in the pipeline where the molten metal is pumped into the extrusion device for intense plastic deformation by an electromagnetic pump, an inductor 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.

[0021] Furthermore, in step three, the degree of severe plastic deformation specifically refers to:

[0022] When the recycled metal is a titanium alloy or a high-strength alloy, the degree of severe plastic deformation is greater than 2.5.

[0023] When the recycled metal material is a high-temperature alloy, the degree of severe plastic deformation is greater than 2.0; when the recycled metal material is an aluminum alloy, the degree of severe plastic deformation is greater than 3.5.

[0024] Furthermore, in step four,

[0025] When the metal recycled material is titanium and titanium alloy, the heat treatment is specifically carried out by holding at 700~980°C for 60min~120min, then air cooling, and then heating it to 450~800°C for 240min~480min and then air cooling.

[0026] When the metal recycled material is aluminum and aluminum alloy, the heat treatment is specifically as follows: after holding at 300°C to 700°C for 60 min to 120 min, it is cooled in the furnace to 200 to 400°C and then taken out and air-cooled.

[0027] When the metal recycled material is a high-temperature alloy, the heat treatment is specifically as follows: after holding at 950°C to 1200°C for 1 to 12 hours, it is air-cooled, and then heated to 600 to 800°C and held for 6 to 12 hours.

[0028] Furthermore, in step four, the removal of the oxide scale from the surface of the rough product is achieved by shot peening, specifically as follows:

[0029] 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 of less than 2 mm.

[0030] When the metal recycled material is aluminum and aluminum alloy, the shot peening abrasive is ceramic shot with a diameter of less than 2 mm.

[0031] Furthermore, in step three, after the recycled metal material undergoes intense casting and extrusion and plastic deformation, it is processed into crude products such as bars, wires, pipes, or profiles, which are used to obtain the corresponding recycled metal products after step four.

[0032] The beneficial effects of this invention are:

[0033] 1. This invention classifies and proportions titanium, aluminum, high-strength and high-temperature alloy scraps, compresses them into blocks, dries the prepared blocks, and then melts them to obtain recycled materials. These materials are then subjected to rapid, continuous, and short-process casting and extrusion with intense plastic deformation, which can achieve 100% recycling of high-value aerospace materials such as titanium, aluminum, high-strength and high-temperature alloys, thereby improving the utilization rate of metal materials.

[0034] 2. The process of this invention is controllable and adjustable, and the prepared recycled material has a uniform structure, fine grains, and excellent mechanical properties, which can effectively eliminate the harmful structures and defects unique to recycled materials.

[0035] 3. This invention combines EB melting with intense plastic deformation casting and extrusion processes, achieving a new high-value metal material recycling process with low overall production costs, as it does not have special requirements on the form, composition, or size of the recycled material, has a short process cycle, and consumes less energy. Attached Figure Description

[0036] Figure 1 This is a process flow diagram of the present invention;

[0037] Figure 2 This is a schematic diagram of the stirring and transport involved in step 2 of the present invention;

[0038] Figure 3 This is a schematic diagram of steps 2-3 of the present invention.

[0039] In the diagram: 1. Inductor coil, 2. Electron beam cold hearth furnace molten pool, 3. Heat transport pipe, 4. Electron gun, 5. Electromagnetic pump, 6. Violent plastic deformation device, 7. Mold, 8. Product. Detailed Implementation

[0040] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0041] Example 1: As Figure 1 As shown, a method for recovering metal using rapid continuous casting and extrusion with severe deformation via EB melting includes:

[0042] Step 1: Processing recycled materials: After sorting, cleaning, and drying the recycled metal materials, add volatile elements according to the needs of the recycled metal, press them into blocks according to the ratio, and dry them; the recycled metal materials are metal blocks, scraps, or powders.

[0043] When the recycled metal material is titanium and titanium alloy, it is washed with a mixture of nitric acid and hydrofluoric acid for 30-40 minutes, rinsed with water, and then dried at 60-80°C.

[0044] Step 2, Melting: The dried material blocks are fed into an electron beam cold hearth furnace to be melted into a molten body. The temperature in the molten pool is controlled by an electron gun, and the molten body is stirred until a metal liquid with a uniform structure and no segregation is obtained.

[0045] The electron beam cold hearth furnace is used for melting at least once, and there are multiple electron guns to meet the energy requirements of melting. At the same time, at least one electron gun is used for melting and heat preservation of the molten pool.

[0046] The stirring device used is an electromagnetic pump or a vibratory stirring device; the stirring current of the electromagnetic pump is adjusted in real time according to the magnetism and state of the metal material.

[0047] Step 3, Intense Plastic Deformation in Casting and Extrusion: Molten metal is pumped into the intense plastic deformation device for intense deformation using an electromagnetic pump. The degree of intense plastic deformation is greater than 2.5, which is used to effectively eliminate special structures and defects in recycled materials.

[0048] In the pipeline where the molten metal is pumped into the extrusion device for intense plastic deformation by an electromagnetic pump, an inductive 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.

[0049] Step 4, Post-processing: After the metal undergoes severe plastic deformation by casting and extrusion, it is subjected to heat treatment, homogenization treatment and straightening in sequence. The oxide scale on the surface of the rough product is removed, and then it is ground and dephosphorized to obtain recycled metal.

[0050] Specifically, the heat treatment involves holding the material at 700~980°C for 60min~120min, followed by air cooling, and then heating it to 450~800°C and holding it for 240min~480min before air cooling. The shot peening abrasive is cast iron shot or cast steel shot with a diameter of less than 2mm.

[0051] Step 5, Regeneration and Recycling: After sorting and processing the waste parts and processing residues generated in the above process, put them into the electron beam cold hearth furnace for recycling.

[0052] Example 2: Same as Example 1, except that...

[0053] The cleaning process in step one is as follows: If the recycled metal material is aluminum or aluminum alloy, it is washed with nitric acid for 20 to 40 minutes, rinsed with water, and then dried at 40 to 50°C.

[0054] In step three, the recycled metal material is an aluminum alloy with a severe degree of plastic deformation greater than 3.5.

[0055] In step four, the recycled metal material is aluminum and aluminum alloy. The heat treatment is as follows: after holding at 300°C to 700°C for 60 to 120 minutes, it is cooled in the furnace to 200 to 400°C and then taken out and air-cooled. The shot peening abrasive is ceramic shot with a diameter of less than 2 mm.

[0056] Example 3: Same as Example 1, except that:

[0057] The cleaning process in step one is as follows: If the recycled metal 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 a temperature of 60 to 80°C.

[0058] In step three, the recycled metal material is a high-temperature alloy with a severe degree of plastic deformation greater than 2.0;

[0059] In step four, the recycled metal material is a high-temperature alloy. The heat treatment is as follows: after holding at 950°C to 1200°C for 1 to 12 hours, it is air-cooled and then heated to 600 to 800°C and held for 6 to 12 hours. The shot peening abrasive is cast iron shot or cast steel shot with a diameter of less than 2 mm.

[0060] Example 4: Similar to Example 1, except that in step three, the recycled metal material is processed into crude products such as bars, wires, pipes or profiles after intense casting and extrusion and plastic deformation, so that the corresponding recycled metal products can be obtained after step four.

[0061] To further illustrate the technical solution and effects of the present invention, the following specific examples are provided. The metal scraps used in the specific embodiments are all derived from the scrap, trimmings, and waste materials generated during the processing of plates, bars, forgings, castings, etc., as well as dismantled parts, physical and chemical materials, etc. Specific Implementation Example 1:

[0063] like Figure 2-3 As shown, a method for recovering metal using rapid continuous casting and extrusion with intense deformation via EB melting is described, with the following specific steps:

[0064] Step 1, Processing the recycled material: The received titanium alloy is pickled with a mixed acid solution of nitric acid and hydrofluoric acid for 30-40 minutes. Pickling is a conventional technique in this field. The specific concentration of the pickling solution is determined based on the morphology and surface condition of the received material. After pickling, the material is rinsed with water. The drying temperature is 60-80°C. The composition of the recycled material is determined using an X-ray composition analyzer, and the mixing ratio is calculated according to the nominal chemical composition of the titanium alloy to be prepared.

[0065] The raw materials include lumpy recycled materials and titanium shells used to wrap the materials, with a total weight of 3000 kg. Among them, 94.13% is TC4 titanium alloy recycled material and 5.87% is pure aluminum residue. The sorted metal materials are supplemented with volatile elements according to the finished product requirements. 2823.9 kg of TC4 titanium alloy recycled material and 176.1 kg of aluminum recycled material are weighed out and the metal recycled materials are pressed into blocks.

[0066] Step 2, Smelting: See Figure 2-3 The dried material blocks are conveyed into the EB furnace for one melting cycle via a conveyor device. The temperature inside the molten pool is controlled by electron guns; seven electron guns are used, determined according to the melting energy requirements. Six electron guns are used for melting, and one is used for melting and maintaining the temperature of the molten pool. The melt is then introduced into an electromagnetic pump and stirred to obtain a uniform, segregated molten metal. The stirring current is 200-500 A. During the transfer process, an inductor coil 1 is wrapped around the heat transfer pipe 3 to stir and maintain the temperature of the melt.

[0067] Step 3, intense plastic deformation by casting and extrusion: The molten metal is introduced into the intense plastic deformation device 6 by casting and extrusion. After intense deformation, a crude product of TC4 titanium alloy recycled bar is obtained in one step. The deformation per pass is 60%, the extrusion rate is 100 mm / s, and the cumulative deformation degree of the cycle is greater than 2.5.

[0068] Step 4, Post-processing: The obtained TC4 recycled titanium alloy bar rough is heat-treated, specifically by holding at 900°C for 60 minutes followed by air cooling, and then holding at 650°C for 240 minutes followed by air cooling. Then, homogenization, straightening, and shaping are performed. Next, shot peening is used to remove the oxide scale generated on the surface after heat treatment, using cast iron shot with a diameter <2mm. Finally, grinding, descaling, and cutting are performed to obtain the TC4 recycled titanium alloy bar.

[0069] Step 5, Recycling: Waste parts and processing residues generated during the production process re-enter the recycling process. After being sorted, cleaned, and pressed into blocks, they are fed into the EB furnace.

[0070] Mechanical properties of TC4 titanium alloy recycled bars were tested, and the comparison results of the mechanical properties of the original titanium alloy and the recycled titanium alloy are shown in Table 1.

[0071] Table 1

[0072]

[0073] The table shows that the tensile strength, yield strength, and maximum elongation of the recycled metal are all improved, indicating a good recycling effect. Specific Implementation Example 2:

[0075] A method for recovering metal using rapid, continuous casting and extrusion with intense deformation via EB melting, comprising the following steps:

[0076] Step 1, Processing the Recycled Material: The received high-temperature alloy is pickled using a mixed solution of hydrochloric acid, hydrofluoric acid, and hydrogen peroxide for 30-40 minutes. Pickling is a standard technique in this field. The specific concentration of the pickling solution is determined based on the morphology and surface condition of the received material. After pickling, the material is rinsed with water. The drying temperature is 60-80°C. The composition of the recycled material is determined using an X-ray composition analyzer. The mixing ratio is calculated according to the nominal chemical composition of the high-temperature alloy to be prepared. The raw materials include blocky recycled material and the titanium shell used to wrap the material blocks, with a total mass of 4000 kg, of which 99.5% is GH4169 high-temperature alloy recycled material, a small amount of aluminum briquettes, and Ni powder. The sorted metal materials are supplemented with volatile elements according to the finished product requirements. 3980 kg of GH4169 alloy recycled material, 15 kg of aluminum briquettes, and 5 kg of nickel powder are weighed out, and the metal recycled material is pressed into blocks.

[0077] Step 2, Smelting: See Figure 2-3 The dried material blocks are conveyed into the EB furnace for one melting cycle via a conveyor device. The temperature inside the molten pool is controlled by seven electron guns, the number determined according to the melting energy requirements. Six guns are used for melting, and one is used for both melting and maintaining the molten pool temperature. The melt is then introduced into an electromagnetic pump and stirred to obtain a uniform, segregated molten metal. The stirring current is 400-600 A. During the transfer process, an inductor coil 1 is wrapped around the heat transfer pipe 3 to stir and maintain the temperature of the melt.

[0078] Step 3, intense plastic deformation by casting and extrusion: The molten metal is introduced into the intense plastic deformation device 6 and processed in one step after intense deformation to obtain the crude product of GH4169 high temperature alloy recycled bar. The deformation amount per pass is 40%, the extrusion rate is 60 mm / s, and the cumulative deformation degree of the cycle is greater than 2.0.

[0079] Step 4, Post-processing: The crude GH4169 high-temperature alloy recycled bar stock undergoes heat treatment. Specifically, it is heated to 1020°C for 60 minutes and then air-cooled; then heated to 720°C for 480 minutes and furnace-cooled to 620°C for 480 minutes, followed by air cooling. Then, homogenization, straightening, and shaping are performed. Shot peening is used to remove the oxide scale generated on the surface after heat treatment. The abrasive used is cast steel shot with a diameter <2mm. Subsequently, grinding, descaling, and cutting are performed to obtain the GH4169 high-temperature alloy recycled bar stock.

[0080] Step 5, Recycling: Waste parts and processing residues generated during the production process re-enter the recycling process. After being sorted, cleaned, and pressed into blocks, they are fed into the EB furnace.

[0081] Mechanical properties of recycled GH4169 high-temperature alloy bars were tested. The comparison results of the mechanical properties of original GH4169 and recycled GH4169 are shown in Table 2.

[0082] Table 2

[0083]

[0084] The table shows that the tensile strength, yield strength, and maximum elongation of the recycled metal are all improved, indicating a good recycling effect.

[0085] The following descriptions are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solutions and improved concepts of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for recycling metals by EB melting, rapid continuous casting, extrusion and severe deformation, characterized in that, The application relates to a method for recycling metal materials, which comprises the following steps: Step 1, processing the recycled materials: after the recycled metal materials are classified, cleaned and dried, volatile elements are supplemented according to the requirements of the recycled metals, the materials are pressed into blocks according to the proportion and dried; Step 2, smelting: the dried blocks are sent into an electron beam cold bed furnace to be smelted into a melt, the temperature in the smelting pool is controlled by using an electron gun, and the melt is stirred until the metal liquid with uniform structure and without segregation is obtained; Step 3, casting-extruding severe plastic deformation: the metal liquid is transported into a casting-extruding severe plastic deformation device by using an electromagnetic pump to be severely deformed, and the severe plastic deformation degree is greater than 2, so that special structures and defects in the recycled materials can be effectively eliminated; Step 4, matched post-processing: after the metal subjected to the casting-extruding severe plastic deformation is sequentially subjected to heat treatment, homogenization treatment and straightening, the oxide skin on the surface of the crude product is removed, and then the crude product is subjected to grinding and dephosphorization treatment, so that the recycled metal is obtained; when the metal recycled materials are titanium and titanium alloy, the heat treatment is specifically as follows: after being kept at 700-980 DEG C for 60-120 min, the metal is air-cooled, and then the metal is heated to 450-800 DEG C and kept for 240-480 min and then air-cooled; when the metal recycled materials are aluminum and aluminum alloy, the heat treatment is specifically as follows: after being kept at 300-700 DEG C for 60-120 min, the metal is air-cooled after being cooled to 200-400 DEG C in the furnace; when the metal recycled materials are high-temperature alloy, the heat treatment is specifically as follows: after being kept at 950-1200 DEG C for 1-12 h, the metal is air-cooled, and then the metal is heated to 600-800 DEG C and kept for 6-12 h; Step 5, recycling: after the waste pieces and machining scraps generated in the above process are classified and treated, the waste pieces and machining scraps are put into the electron beam cold bed furnace for recycling. In step 1, the metal recycled materials are block materials, scrap materials or powder materials. In step 1, the cleaning is specifically as follows: when the metal recycled materials are titanium and titanium alloy, the metal is washed by using mixed acid liquid of nitric acid and hydrofluoric acid for 30-40 min, and then the metal is washed by water and dried at 60-80 DEG C; when the metal recycled materials are aluminum and aluminum alloy, the metal is washed by using nitric acid for 20-40 min, and then the metal is washed by water and dried at 40-50 DEG C; when the metal recycled materials are high-temperature alloy, the metal is washed by using mixed solution of hydrochloric acid, hydrofluoric acid and hydrogen peroxide for 20-40 min, and then the metal is washed by water and dried at 60-80 DEG C. In step 2, the number of smelting in the electron beam cold bed furnace is at least 1, and the number of electron guns is multiple, so that the energy requirement of smelting can be met, and at least one electron gun is used for smelting and smelting pool heat preservation. In step 2, the stirring device is an electromagnetic pump or a vibration stirring device; and the stirring current of the electromagnetic pump is adjusted in real time according to the magnetism and state of the metal material. In step 3, an inductance coil is used to stir and heat the melt in the pipeline through which the metal liquid is transported into the casting-extruding severe plastic deformation device, so that the metal liquid is kept in a flowing state and the structure of the metal liquid is kept uniform and non-segregated. In step 3, the severe plastic deformation degree is specifically as follows: ​ ​ 2. The method of recycling metals by EB melting and rapid continuous casting-extrusion severe deformation according to claim 1, wherein ​ 3. The method of claim 1, wherein the method is characterized by: ​ ​ ​ ​ 4. The method of claim 1, wherein the method is characterized by: ​ 5. The method of claim 1, wherein the method is characterized by: ​ 6. The method of claim 1, wherein the method is characterized by: ​ 7. The method of claim 1, wherein the method is characterized by: ​ When the metal recycled material is titanium alloy, the degree of severe plastic deformation is greater than 2.5; When the metal recycled material is high-temperature alloy, the degree of severe plastic deformation is greater than 2.0; when the metal recycled material is aluminum alloy, the degree of severe plastic deformation is greater than 3.

5.

8. The method of claim 1, wherein the method is characterized by: In step four, the oxide skin on the surface of the crude product is removed by shot blasting, specifically: When the metal recycled material is titanium and titanium alloy, the shot blasting abrasive is cast iron shot or cast steel shot with a diameter less than 2 mm; When the metal recycled material is aluminum and aluminum alloy, the shot blasting abrasive is ceramic shot with a diameter less than 2 mm.

9. The method of recycling metals by EB melting and rapid continuous casting-extrusion severe deformation according to any one of claims 1-8, characterized in that, In step three, the metal recycled material is processed into a crude product in the form of a rod, wire, tube or profile after severe casting and extrusion and severe plastic deformation, so as to obtain the corresponding recycled metal product after step four.

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