Waste aluminum regeneration rolling-in-situ alloying short-process technology

Abstract

The invention discloses a waste aluminum regeneration calendering-in-situ alloying short-process technology, and relates to the field of advanced nonferrous metal material preparation and resource recycling. The method comprises the following steps: after crushing and pretreating the waste aluminum, mixing the waste aluminum with Cu / Zn / Mg alloy powder, and carrying out cold press molding to obtain a precast block; carrying out hot extrusion by adopting a conventional hot extrusion machine, and synchronously breaking the film and alloying; continuously rolling and densifying an interface; and carrying out online T6 heat treatment to obtain the high-performance aluminum alloy. According to the method, special equipment and a smelting process are replaced by conventional hot extrusion and continuous calendering, the technical prejudice is broken through, special equipment does not need to be additionally arranged, the single-batch treatment capacity is 1.5 tons, and the production period is 2.2-2.5 hours. The oxygen content of the product is smaller than or equal to 0.1 at.%, the yield strength is larger than or equal to 262 MPa, the tensile strength is larger than or equal to 438 MPa, high-end regeneration of waste aluminum is achieved, the method is suitable for scenes such as automobile light weight, and economic and environment-friendly values are achieved.

Description

Technical Field

[0001] This invention relates to the intersection of advanced non-ferrous metal material preparation and resource recycling, and specifically proposes a short-process technology for waste aluminum recycling, rolling, and in-situ alloying. Background Technology

[0002] Currently, waste aluminum recycling technologies are mainly divided into two categories: smelting recycling and solid-state recycling. Smelting recycling involves multiple steps: "waste aluminum crushing - smelting and impurity removal - alloying element addition - ingot casting - hot rolling - offline heat treatment," a process that takes over 72 hours. The smelting stage accounts for over 60% of energy consumption, and the high-temperature environment easily leads to oxidation and burn-off, resulting in recycled aluminum with an oxygen content as high as 0.3-0.5 at.%, indicating low performance, suitable only for low-end products. Solid-state recycling eliminates the smelting step, but only achieves simple forming through "crushing - cold pressing - hot extrusion / rolling," without alloying treatment. The product is low-strength pure aluminum, and the scrap aluminum fragments are mechanically bonded, with interfaces prone to porosity and inclusions, failing to meet the material performance requirements of high-end equipment.

[0003] Existing in-situ alloying technologies are only applicable to primary metals with uniform composition, relying on high-temperature sintering or specialized friction extrusion equipment to dissolve alloying elements. They fail to consider the problem of element diffusion being hindered by the oxide film (Al2O3) on the surface of waste aluminum, making them unsuitable for direct application in waste aluminum recycling scenarios. A long-standing technical bias in this field holds that "waste aluminum must be smelted and impurity removed or rely on specialized friction extrusion equipment to achieve alloying." This leads to shortcomings in existing technologies, such as strong equipment dependence, difficulty in industrial mass production, and limited product forms (mostly small-diameter bars), hindering the upgrading and transformation of waste aluminum into high-end aluminum alloys. Summary of the Invention

[0004] In view of this, the present invention proposes a short process for waste aluminum recycling, rolling and in-situ alloying, aiming to break the equipment dependence and technical bias of the existing technology and realize the industrial integrated production of waste aluminum recycling and alloying.

[0005] The technical solution of this invention is achieved as follows: This invention provides a short-process technology for recycled aluminum rolling and in-situ alloying, comprising the following steps: (1) After being crushed and pretreated, the waste aluminum raw material is mixed with Cu / Zn / Mg alloy powder to obtain a mixed raw material; (2) The mixed raw materials are cold-pressed to form preforms; (3) The preform is hot-extruded using a conventional hot extrusion press to simultaneously break the oxide film on the surface of the waste aluminum and dissolve the alloying elements in situ to obtain the extruded billet; (4) The extruded billet is continuously rolled to obtain a rolled sheet; 5. The rolled sheet is subjected to online heat treatment to obtain a high-performance recycled aluminum alloy.

[0006] The conventional hot extrusion press is an industrial-grade extrusion equipment without a spiral groove die.

[0007] In some embodiments, in step 1, the waste aluminum raw material is waste aluminum from door and window profiles or industrial aluminum scraps, with a particle size of 1-5mm after crushing.

[0008] Scrap aluminum from door and window profiles and industrial aluminum scraps are types of scrap aluminum with large output and stable recycling channels in the industrial field. Selecting this type of raw material can ensure the stability of the raw material supply for the process. Crushing the scrap aluminum to 1-5mm can avoid uneven distribution of alloy powder in the mixed raw materials due to excessively large particle size, and can also prevent excessively small particle size from increasing crushing energy consumption and oxidation risk, thus providing a uniform material basis for subsequent cold pressing and hot extrusion alloying.

[0009] In some embodiments, in step 1, the mass ratio of the mixed raw materials is: 88-92% waste aluminum, 5.6% Zn, 1.6% Cu, and 2.5% Mg, and the particle size of the Cu / Zn / Mg alloy powder is 10-50 μm. Principle analysis: This ratio precisely matches the compositional requirements of 7075 series high-performance aluminum alloys. Through the synergistic effect of Zn, Cu, and Mg elements, it lays the compositional foundation for the precipitation of the GP zone and η' strengthening phase during subsequent heat treatment. Controlling the alloy powder particle size to 10-50 μm balances dissolution efficiency and mixing uniformity: excessively small particle sizes easily agglomerate, while excessively large particle sizes are difficult to completely dissolve during hot extrusion. This particle size range ensures that the alloy elements diffuse rapidly and are evenly distributed within the aluminum matrix.

[0010] In some embodiments, in step 2, the cold pressing pressure is 110-120 MPa, and the density of the resulting preform is ≥2.5 g / cm³. 3 .

[0011] Cold pressing pressure of 110-120 MPa can create close contact between the mixed raw material particles, reduce porosity, and achieve a preform density ≥2.5 g / cm³. 3 It can avoid localized oxidation or forming defects caused by loose materials during hot extrusion, and at the same time provide a guarantee for the transmission of shear stress during hot extrusion, ensuring that the oxide film breakage and alloying reaction proceed simultaneously.

[0012] In some embodiments, in step 3, the temperature of the hot extrusion treatment is 400-450°C, the extrusion speed is 4-6 mm / min, and the extrusion ratio is 15-20:1.

[0013] 400-450℃ is the optimal temperature range for Cu / Zn / Mg alloy powder to dissolve in an aluminum matrix: below 400℃, the diffusion rate of alloying elements is slow, making full alloying impossible; above 450℃, scrap aluminum is prone to softening and deformation, affecting forming accuracy. An extrusion speed of 4-6 mm / min combined with an extrusion ratio of 15-20:1 can generate sufficient shear stress to effectively break the oxide film (Al2O3) on the surface of scrap aluminum, while simultaneously promoting interfacial fusion between the alloy powder and the aluminum matrix. This breaks the technical prejudice that "conventional hot extrusion cannot remove the oxide film from scrap aluminum," achieving simultaneous oxide film breaking and alloying.

[0014] In some embodiments, in step 3, the preform is preheated to 150-200°C before hot extrusion.

[0015] Preheating the preform can reduce the temperature gradient during hot extrusion, avoiding stress concentration and cracking caused by excessive internal and external temperature differences; a preheating temperature of 150-200℃ can reduce the deformation resistance during extrusion, improve the smoothness of forming, and prevent the alloy powder from oxidizing prematurely, ensuring the stability of the subsequent alloying effect.

[0016] In some implementations, in step 4, the continuous rolling process consists of 3-5 passes, and the rolling temperature is 380-420°C.

[0017] Continuous rolling in 3-5 passes can gradually refine the grains and densify the interface, avoiding cracking of the sheet caused by a large reduction rate in a single pass; the rolling temperature of 380-420℃ forms a connection with the hot extrusion temperature, maintaining the plastic state of the aluminum matrix, while providing temperature conditions for further diffusion of alloying elements, ensuring the tightness of the interface bonding.

[0018] In some embodiments, in step 4, the reduction rate of the continuous calendering increases with each pass and ranges from 20% to 35%, the calendering speed is 2-3 m / min, and the thickness of the calendered sheet is 3-5 mm.

[0019] The progressively increasing reduction rate transforms the mechanical bonding interface of scrap aluminum into dense grain boundaries. A reduction rate range of 20%-35% balances the densification effect with the forming precision of the sheet, avoiding insufficient bonding due to an excessively low reduction rate or warping caused by an excessively high reduction rate. A rolling speed of 2-3 m / min is suitable for continuous industrial production, and a sheet thickness of 3-5 mm meets the needs of high-end applications such as lightweight automotive materials and high-end window and door profiles, overcoming the limitations of existing technologies that primarily produce small-diameter bars.

[0020] In some implementations, in step 5, the online heat treatment adopts the T6 process, specifically: solution treatment at 480°C for 45 minutes, followed by water quenching and cooling, and then aging treatment at 120°C for 24 hours.

[0021] Solution treatment at 480℃ allows alloying elements to fully dissolve and distribute evenly in the aluminum matrix, while a holding time of 45 minutes ensures sufficient solution. Water quenching can quickly suppress the precipitation of alloying elements and obtain a supersaturated solid solution. Aging treatment at 120℃ for 24 hours can induce the uniform precipitation of GP zone and η' strengthening phase, significantly improving the mechanical properties of the material and ultimately enabling the recycled aluminum alloy to reach the high-performance level of 7075.

[0022] In some embodiments, in step 1, the mixing time of the mixed raw materials is 15-20 minutes; in step 3, the conventional hot extruder is an industrial-grade extrusion equipment without a spiral groove die.

[0023] A mixing time of 15-20 minutes ensures that scrap aluminum fragments and alloy powder are mixed evenly, avoiding local component segregation that could affect product performance consistency. Choosing an industrial-grade conventional hot extrusion press without spiral groove molds can be directly adapted to the company's existing production equipment, eliminating the need for additional specialized equipment, reducing industrialization promotion costs, and solving the mass production problems caused by the reliance on specialized friction extrusion equipment in existing technologies.

[0024] The present invention has the following advantages over the prior art: This invention breaks away from the technical prejudice that scrap aluminum must be smelted or rely on specialized equipment for alloying through an integrated short-process design encompassing pretreatment, cold pressing, conventional hot extrusion, continuous rolling, and online heat treatment. It achieves simultaneous recycling and alloying of scrap aluminum. The combined process of conventional hot extrusion and continuous rolling solves the problems of high energy consumption and severe oxidation loss in existing smelting processes, while overcoming the shortcomings of poor performance and insufficient interfacial bonding in solid-state regeneration processes. All process parameters are compatible with industrial-grade equipment, and the single-batch processing capacity can reach 1-2 tons, meeting the needs of large-scale production. Simultaneously, through the synergistic optimization of raw material ratios and process parameters, low-value scrap aluminum is transformed into high-performance aluminum alloy sheets, expanding the high-end application scenarios of recycled aluminum and possessing significant economic, environmental, and industrial upgrading value. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1 Step 1: Select scrap aluminum from door and window profiles as raw material. Its composition is Al 99.2%, Fe 0.5%, and Si 0.3%. After removing surface oil and coating, crush it into 2-3mm pieces and screen to remove impurities such as iron filings and plastic. Weigh 90% scrap aluminum, 5.6% Zn, 1.6% Cu, and 2.5% Mg according to the mass ratio. The particle size of Cu / Zn / Mg alloy powder is 20-30μm. Put the scrap aluminum pieces and alloy powder into a mixing device and mix for 18 minutes to obtain mixed raw materials.

[0027] Step 2: The mixed raw materials are fed into a hydraulic press and cold-pressed under a pressure of 115 MPa to obtain precast blocks with dimensions of Φ100mm × 300mm. The density of the precast blocks is measured to be 2.55 g / cm³. 3 .

[0028] Step 3: Preheat the preform to 180℃, then feed it into an industrial-grade conventional hot extrusion press without a spiral groove mold. Control the hot extrusion temperature to 420℃, the extrusion speed to 5mm / min, and the extrusion ratio to 18:1. Perform hot extrusion treatment on the preform, simultaneously breaking the oxide film on the surface of the waste aluminum and dissolving the alloying elements in situ to obtain the extruded billet.

[0029] Step 4: The extruded billet is directly fed into a continuous rolling mill and subjected to four consecutive rolling passes at a rolling temperature of 380-420℃. The reduction rates are 20%, 25%, 30%, and 35% respectively, and the rolling speed is 2.5m / min, to obtain a rolled sheet with a thickness of 4mm.

[0030] Step 5: The rolled sheet is sent to an online heat treatment device and treated with the T6 process, specifically solution treatment at 480℃ for 45 minutes, followed by water quenching (cooling rate ≥20℃ / s), and then aging treatment at 120℃ for 24 hours to obtain a high-performance recycled aluminum alloy.

[0031] Example 2 Step 1: Completely consistent with Step 1 of Example 1.

[0032] Step 2: Completely consistent with Step 2 of Example 1.

[0033] Step 3: Completely consistent with Step 3 of Example 1.

[0034] Step 4: The extruded billet is directly fed into a continuous rolling mill and subjected to three consecutive rolling passes at a rolling temperature of 380-420℃, with reduction rates of 25%, 30%, and 35% respectively, and a rolling speed of 2.5m / min, to obtain a rolled sheet with a thickness of 5mm.

[0035] Step 5: Completely consistent with Step 5 of Example 1.

[0036] Example 3 Step 1: Completely consistent with Step 1 of Example 1.

[0037] Step 2: Completely consistent with Step 2 of Example 1.

[0038] Step 3: Preheat the preform to 180℃, then feed it into an industrial-grade conventional hot extrusion press without a spiral groove mold. Control the hot extrusion temperature to 440℃, the extrusion speed to 4.5mm / min, and the extrusion ratio to 18:1. Perform hot extrusion treatment on the preform, simultaneously breaking the oxide film on the surface of the waste aluminum and dissolving the alloying elements in situ to obtain the extruded billet.

[0039] Step 4: Completely consistent with Step 4 of Example 1.

[0040] Step 5: Completely consistent with Step 5 of Example 1.

[0041] Example 4 Step 1: Select industrial aluminum scrap as raw material, with the composition of Al 98.8%, Fe 0.6%, Cu 0.2%, and Si 0.4%. After removing surface oil and coating, crush it into 1-4mm pieces and screen to remove impurities such as iron filings and plastic. Weigh 90% waste aluminum, 5.6% Zn, 1.6% Cu, and 2.5% Mg according to the mass ratio. The particle size of the Cu / Zn / Mg alloy powder is 20-30μm. Put the waste aluminum scrap and alloy powder into a mixing device and mix for 18 minutes to obtain mixed raw materials.

[0042] Step 2: The mixed raw materials are fed into a hydraulic press and cold-pressed under a pressure of 115 MPa to obtain precast blocks with dimensions of Φ100mm × 300mm. The density of the precast blocks is measured to be 2.52 g / cm³. 3 .

[0043] Step 3: Completely consistent with Step 3 of Example 1.

[0044] Step 4: Completely consistent with Step 4 of Example 1.

[0045] Step 5: Completely consistent with Step 5 of Example 1.

[0046] Example 5 Step 1: Completely consistent with Step 1 of Example 1.

[0047] Step 2: Completely consistent with Step 2 of Example 1.

[0048] Step 3: The preform is directly fed into an industrial-grade conventional hot extrusion press without a spiral groove mold. No preheating is required. The hot extrusion temperature is controlled at 420℃, the extrusion speed is 5mm / min, and the extrusion ratio is 18:1. The preform is hot extruded, and the oxide film on the surface of the waste aluminum is broken and the alloying elements are dissolved in situ to obtain the extruded billet.

[0049] Step 4: Completely consistent with Step 4 of Example 1.

[0050] Step 5: Completely consistent with Step 5 of Example 1.

[0051] Comparative Example 1 Step 1: Completely consistent with Step 1 of Example 1.

[0052] Step 2: The mixed raw materials are fed into a hydraulic press and cold-pressed under a pressure of 110 MPa to obtain preforms with dimensions of Φ50mm × 100mm. The density of the preforms is measured to be 2.5 g / cm³. 3 .

[0053] Step 3: Using a special friction extrusion equipment with spiral grooves, the extrusion temperature is controlled at 400℃ and the extrusion time is 5 minutes to perform friction extrusion treatment on the preform to obtain a 5mm diameter rod-shaped billet without a continuous rolling step.

[0054] Step 4: The bar billet is fed into a heat treatment device and treated using the T6 process, specifically solution treatment at 480℃ for 45 minutes, followed by water quenching and cooling, and then aging treatment at 120℃ for 24 hours to obtain recycled aluminum alloy bars.

[0055] Comparative Example 2 Step 1: Completely consistent with Step 1 of Example 1.

[0056] Step 2: Completely consistent with Step 2 of Example 1.

[0057] Step 3: Completely consistent with Step 3 of Example 1.

[0058] Step 4: The extruded billet obtained by hot extrusion is not subjected to continuous rolling treatment, but is directly sent to an online heat treatment device and treated with the T6 process, specifically solution treatment at 480℃ for 45 minutes, followed by water quenching and cooling, and then aging treatment at 120℃ for 24 hours to obtain recycled aluminum alloy profiles.

[0059] Comparative Example 3 Step 1: Completely consistent with Step 1 of Example 1.

[0060] Step 2: Completely consistent with Step 2 of Example 1.

[0061] Step 3: Preheat the preform to 180°C, then feed it into an industrial-grade conventional hot extrusion press without a spiral groove die. Control the hot extrusion temperature to 380°C, the extrusion speed to 3mm / min, and the extrusion ratio to 18:1 to perform hot extrusion treatment on the preform to obtain the extruded billet.

[0062] Step 4: Completely consistent with Step 4 of Example 1.

[0063] Step 5: Completely consistent with Step 5 of Example 1.

[0064] Comparative Example 4 Step 1: Completely consistent with Step 1 of Example 1.

[0065] Step 2: Completely consistent with Step 2 of Example 1.

[0066] Step 3: Completely consistent with Step 3 of Example 1.

[0067] Step 4: Completely consistent with Step 4 of Example 1.

[0068] Step 5: The rolled sheet is not subjected to online heat treatment, but is directly cooled naturally to obtain recycled aluminum alloy sheet.

[0069] Comparative Example 5 Step 1: Select the same scrap aluminum door and window profiles as in Example 1 as raw material, remove surface oil and coating, crush into 10-20mm pieces, and screen to remove impurities.

[0070] Step 2: The scrap aluminum pieces are fed into a smelting furnace and smelted at 720°C to remove impurities. Then, alloying elements of Zn 5.6%, Cu 1.6%, and Mg 2.5% are added according to the mass ratio. After stirring evenly, the mixture is cast into an ingot to obtain an aluminum alloy ingot.

[0071] Step 3: Heat the aluminum alloy ingot to 450℃ and send it into the rolling mill for rolling to obtain a plate with a thickness of 4mm.

[0072] Step 4: The sheet material is sent to a heat treatment device and processed using the offline T6 process, specifically solution treatment at 480℃ for 45 minutes, followed by water quenching and cooling, and then aging treatment at 120℃ for 24 hours to obtain recycled aluminum alloy sheet material.

[0073] Performance verification 1. Oxygen content test: Using an oxygen and nitrogen analyzer, three test points were selected in the central and edge areas of each example and comparative example product. The oxygen content of each test point was measured, and the average value of the six test points was taken as the final oxygen content data.

[0074] 2. Grain size test: The product is made into a metallographic sample, and after grinding, polishing and etching, it is observed with a metallographic microscope. Five different fields of view are selected, and the grain size is measured by image analysis software. The average value is taken as the final grain size data.

[0075] 3. Mechanical property testing: In accordance with GB / T228.1-2010 standard, standard tensile specimens were prepared and tensile tests were conducted using a universal testing machine to determine the yield strength and tensile strength. Each sample was tested 3 times, and the average value was taken as the final mechanical property data.

[0076] 4. Interface porosity test: The product is made into a scanning electron microscope sample, and the microstructure of the interface is observed using a scanning electron microscope. Five different fields of view are selected, and the interface porosity is calculated using image analysis software. The average value is taken as the final interface porosity data.

[0077] 5. Oxide film breakage rate test: The surface and cross-sectional morphology of the billet after hot extrusion were observed by scanning electron microscopy. The area of ​​oxide film breakage was counted. Five different fields of view were selected, and the average value was taken as the oxide film breakage rate data.

[0078] 6. Statistics on single batch processing capacity and production cycle: Record the entire process time from raw material pretreatment to finished product output for each example and comparative example as the production cycle; calculate the maximum processing capacity of a single feeding as the single batch processing capacity.

[0079] Performance verification results

[0080] Based on the performance verification results of Examples 1-5 and Comparative Examples 1-5, it can be seen that the present invention, through a short-process technology of "conventional hot extrusion + continuous rolling + online T6 heat treatment", can stably produce high-performance aluminum alloy sheets with oxygen content ≤0.1 at.%, yield strength ≥262MPa, and tensile strength ≥438MPa, regardless of the type of waste aluminum raw material, whether the rolling passes are adjusted, or whether the preheating step of the preform is omitted. Moreover, the single batch processing capacity reaches 1.5 tons, the production cycle is only 2.2-2.5 hours, it is compatible with existing industrial equipment, and the equipment investment cost is low.

[0081] Compared with the dedicated friction extrusion scheme of Comparative Example 1, this invention does not rely on special equipment, can achieve mass production of sheet metal with significantly lower oxygen content; after Comparative Example 2 omitted the continuous rolling step, the interfacial porosity soared to 8%, and the mechanical properties dropped significantly, proving that rolling is the core of interfacial densification; after the hot extrusion parameters of Comparative Example 3 deviated from the limits of this invention, the oxide film breakage rate was only 75%, indicating insufficient alloying; after Comparative Example 4 omitted online heat treatment, the yield strength was less than 180MPa, highlighting the synergistic strengthening effect of the process combination; the traditional smelting process of Comparative Example 5 is comprehensively inferior in terms of energy consumption, cycle time, and performance.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A short-process technology for recycled aluminum rolling-in-situ alloying, characterized in that, Includes the following steps: (1) After being crushed and pretreated, waste aluminum raw materials are mixed with Cu / Zn / Mg alloy powder to obtain mixed raw materials; (2) The mixed raw materials are cold-pressed into preforms to obtain preforms; (3) The preform is hot-extruded using a hot extrusion press to simultaneously break the oxide film on the surface of waste aluminum and dissolve alloying elements in situ to obtain extruded billets. (4) The extruded billet is subjected to continuous rolling to obtain a rolled sheet; (5) The rolled sheet is subjected to online heat treatment to obtain a high-performance recycled aluminum alloy.

2. The process according to claim 1, characterized in that, In step 1, the waste aluminum raw material is waste aluminum from door and window profiles or industrial aluminum scraps, with a particle size of 1-5mm after crushing.

3. The process according to claim 1 or 2, characterized in that, In step 1, the mass ratio of the mixed raw materials is: 88-92% waste aluminum, 5.6% Zn, 1.6% Cu, and 2.5% Mg, and the particle size of the Cu / Zn / Mg alloy powder is 10-50 μm.

4. The process according to claim 1, characterized in that, In step 2, the cold pressing pressure is 110-120 MPa, and the density of the resulting preform is ≥2.5 g / cm³. 3 .

5. The process according to claim 1, characterized in that, In step 3, the temperature of the hot extrusion treatment is 400-450℃, the extrusion speed is 4-6mm / min, and the extrusion ratio is 15-20:

1.

6. The process according to claim 1 or 5, characterized in that, In step 3, the preform is preheated to 150-200°C before hot extrusion.

7. The process according to claim 1, characterized in that, In step 4, the continuous rolling process consists of 3-5 passes, and the rolling temperature is 380-420℃.

8. The process according to claim 1 or 7, characterized in that, In step 4, the reduction rate of the continuous calendering increases with each pass and ranges from 20% to 35%, the calendering speed is 2-3 m / min, and the thickness of the calendered sheet is 3-5 mm.

9. The process according to claim 1, characterized in that, In step 5, the online heat treatment adopts the T6 process, which is: solution treatment at 480℃ for 45 minutes, followed by water quenching and cooling, and then aging treatment at 120℃ for 24 hours.

10. The process according to claim 1, characterized in that, In step 1, the mixing time of the mixed raw materials is 15-20 minutes; in step 3, the conventional hot extrusion press is an industrial-grade extrusion equipment without a spiral groove die.

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