Metal extrusion and expansion forming device and method based on extrusion and rotary expansion combination and product

Abstract

The invention discloses a metal extrusion and expansion forming device and method based on extrusion and rotary expansion combination and a product, and belongs to the technical field of metal plastic processing. The device comprises an extrusion system, an expansion forming system, a transition ring, a cutting system and a control system. The core of the method is as follows: after a metal casting blank is positively extruded by an extrusion die, the metal casting blank is immediately subjected to diameter expansion and extension deformation on the surface of a forming core die which is coaxially arranged to form a continuous product blank; single products are separated through fixed-length cutting, the core mold is moved to take out the products, and circulating production is achieved. And the forming core mold can be fixed or rotated. Short-process, near-net-shape and semi-continuous production from casting blanks to complex parts (such as conical parts and corrugated pipes) is achieved, and the method has the advantages of being high in performance, high in efficiency and low in cost and is a great innovation for a traditional spinning technology.

Description

Technical Field

[0001] This invention belongs to the field of metal plastic processing technology, specifically relating to a metal extrusion forming device, method, and product based on a combination of extrusion and spin expansion. Background Technology

[0002] Spin forming is an important method for manufacturing axisymmetric thin-walled rotating parts (such as conical and cylindrical parts). However, traditional spin forming technology usually uses pre-made sheet metal or tubes as blanks, which has the following inherent drawbacks: 1) Long production process, requiring pre-preparation of sheet metal or tube blanks, resulting in high material and energy consumption; 2) Relatively low material utilization rate; 3) Challenges in production efficiency and cost control; 4) Difficulty in producing asymmetric variable cross-section irregular parts.

[0003] Extrusion molding can achieve large plastic deformation of metals, refine grains, and is easy to connect with cast billets. However, traditional extrusion mainly produces profiles with constant cross-sections, and it is difficult to directly form complex rotating parts with variable cross-sections or asymmetric variable cross-section irregular parts.

[0004] Therefore, the industry urgently needs a new plastic processing technology that can integrate the advantages of extrusion and spinning technologies, directly use cast billets as raw materials, and efficiently, cost-effectively, and with high quality produce complex rotating parts or asymmetric variable cross-section irregular parts, and can adapt to continuous or semi-continuous production modes. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention aims to provide a metal extrusion forming apparatus, method, and products based on a combination of extrusion and spin-expansion. It is particularly suitable for the efficient and continuous manufacturing of conical, variable cross-section, and irregularly shaped cylindrical metal products. Its core lies in combining the advantages of short-process, large-deformation forward extrusion with the progressive forming and flexible variable cross-section capabilities of spin-expansion / diameter expansion. This achieves integrated near-net-shape forming from metal castings to high-performance, complex-shaped products, and enables continuous, separate production of the products through sawing and other methods. Another objective of this invention is to disclose the various product shapes that this method can produce and their corresponding production modes. It can not only produce axisymmetric rotating parts that can be manufactured using traditional spin forming, but also asymmetric variable cross-section irregularly shaped parts that cannot be manufactured using traditional spin forming.

[0006] In particular, compared with existing technologies, this invention integrates extrusion forming and spin-expansion forming in a spatiotemporal manner. By utilizing the high temperature and high strain energy state generated by extrusion, dynamic recrystallization in the spin-expansion zone is immediately triggered, which helps to achieve one-step microstructure optimization from metal casting to ultra-fine-grained high-performance products. The comprehensive mechanical properties of the products are significantly better than those of traditional step-by-step processes. At the same time, spin-expansion in the strong triaxial compressive stress field provided by extrusion will fundamentally inhibit crack initiation and heal original defects, greatly improving the forming limit of difficult-to-deform materials and the density of products. Moreover, it will achieve efficient recycling of deformation heat energy and mechanical stored energy, eliminating intermediate cooling and reheating processes, significantly reducing overall energy consumption, and forming a new green manufacturing model with extremely short process and low carbon emissions. In addition, starting with a highly uniform extruded billet, the final finishing through spin-expansion will achieve precise control of the wall thickness of complex variable cross-section products and simultaneous improvement of surface quality. In summary, this invention achieves a revolutionary breakthrough in product performance, forming capability, manufacturing efficiency, and energy consumption by deeply coupling and mutually promoting the two plastic deformation mechanisms of extrusion and spin expansion at the physical field (stress, strain, temperature) level. This breakthrough goes beyond the simple combination of the two existing technologies.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: According to a first aspect of the technical solution of the present invention, a metal extrusion forming apparatus is provided, comprising an extrusion system, an expansion forming system, a transition ring, a cutting system and a control system; The extrusion system includes an extrusion rod, an extrusion cylinder, and an extrusion die installed at the front end of the extrusion cylinder; The expansion forming system includes a forming core die coaxially disposed in front of the extrusion die outlet, a core die holder for mounting and fixing or driving the forming core die to rotate, and a translation mechanism for driving the core die holder to move axially. The transition ring is positioned between the extrusion die outlet and the forming core die so that it can be opened to facilitate the cutting of the extruded billet. The cutting system is installed next to the transition ring and is used to cut the billet extruded at the transition ring; The control system is used to coordinate and control the advancement of the extrusion rod, the movement (rotation and translation) of the forming mandrel, the opening and closing of the transition ring, and the operation of the cutting system.

[0008] Furthermore, the expansion forming system also includes a rotary drive mechanism for driving the forming core mold to rotate.

[0009] Furthermore, the cutting system is a flying saw, hydraulic shears, or a laser cutting head.

[0010] According to a second aspect of the present invention, a metal extrusion forming method employing a metal extrusion forming apparatus according to any one of the above aspects is provided, comprising the following steps: S1: Place the metal billet into the extrusion cylinder; S2: Apply axial pressure to the metal billet using an extrusion rod, causing it to be extruded forward through an extrusion die to form a billet with preliminary deformation; S3: Outside the outlet end of the extrusion die, the front end of the extruded billet passes through a coaxially arranged transition ring and then contacts a coaxially arranged forming core die. S4: Under the action of axial thrust, the extruded preform undergoes continuous plastic deformation on the contour surface of the forming mandrel, realizing a composite deformation of radial expansion and axial extension, forming a continuous target product preform. S5: After the blank of the required length of the product is formed, the transition ring is opened to separate and cut the blank located at the transition ring. S6: Move the forming core along the axial direction away from the cut product, remove the product, and then reset the forming core to prepare for the extrusion forming of the next product.

[0011] Furthermore, in step S4, the forming core mold is either in a fixed state or in a state of rotation about its axis.

[0012] Furthermore, the separation and cutting in step S5 is performed by sawing, shearing, or laser cutting.

[0013] Furthermore, the working surface of the forming core mold is a conical surface, a curved surface, a stepped surface, or a combination thereof.

[0014] Furthermore, the outlet of the extrusion die is an annular or solid die opening, which applies lubrication to the inner surface of the extrusion cylinder, the inner surface of the extrusion die, the inner surface of the transition ring, or the outer surface of the forming core mold.

[0015] According to a third aspect of the technical solution of the present invention, a metal article produced by the method described in any of the above aspects is provided, wherein the article is an axisymmetric rotating body part or an asymmetric variable cross-section irregular part having variable cross-section characteristics, formed by integral extrusion and expansion and then cut and separated.

[0016] Furthermore, the product is any one of the following: tapered part, variable diameter pipe part, flanged cylindrical part, stepped cylindrical part, corrugated pipe part, or asymmetric variable cross-section irregular part.

[0017] Beneficial effects of the present invention Compared with the prior art, the present invention has the following significant advantages: 1. Extremely short process and reduced cost: Direct use of low-cost cast billets eliminates the plate / tube billet prefabrication process required for traditional spinning, significantly shortening the process flow and reducing energy consumption and production costs.

[0018] 2. Near-net-shape forming with high material utilization: The metal flow lines are continuous during the forming process, with no or very little cutting, resulting in high material utilization.

[0019] 3. Excellent microstructure and properties: The large plastic deformation brought about by extrusion fully refines the as-cast microstructure; during subsequent expansion, the metal continues to undergo plastic deformation, thereby further improving the microstructure and resulting in excellent mechanical properties of the product.

[0020] 4. Flexible and efficient production mode: Through the cycle of "extrusion-expansion-sawing", semi-continuous production from continuous deformed body to discrete product is achieved, with efficiency far exceeding that of traditional spinning for single-piece production. The design of the mandrel, which can be rotated or fixed, provides room for process optimization.

[0021] 5. Flexible production capability: By changing the forming mandrel with different contours, a variety of products with different cross-sections can be flexibly produced on the same device. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of an embodiment of the metal extrusion forming apparatus of the present invention (rotatable core mold mode).

[0024] Among them, 1-extrusion rod, 2-extrusion cylinder, 3-metal casting billet, 4-extrusion die, 5-transition ring, 6-forming core mold, 7-core mold base, 8-translation mechanism, 9-forming billet, 10-cutting system, 11-separated product, 12-control system.

[0025] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0026] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0027] The terms "first," "second," etc., used in this disclosure are for distinguishing similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that the embodiments of this disclosure described herein can be implemented, for example, in orders other than those illustrated or described herein.

[0028] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0029] Multiple, including two or more.

[0030] And / or, it should be understood that, for the purposes of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0031] The technical solution of this invention first provides a metal extrusion forming apparatus, including an extrusion system, an expansion forming system, a transition ring, a cutting system, and a control system; The extrusion system includes an extrusion rod, an extrusion cylinder, and an extrusion die installed at the front end of the extrusion cylinder; The expansion forming system includes a forming core die coaxially disposed in front of the extrusion die outlet, a core die holder for mounting and fixing or driving the forming core die to rotate, and a translation mechanism for driving the core die holder to move axially. The transition ring is positioned between the extrusion die outlet and the forming core die so that it can be opened to facilitate the cutting of the extruded billet. The cutting system is installed next to the transition ring and is used to cut the billet extruded at the transition ring; The control system is used to coordinate and control the advancement of the extrusion rod, the movement (rotation and translation) of the forming mandrel, the opening and closing of the transition ring, and the operation of the cutting system.

[0032] The present invention further provides a metal extrusion forming method based on the above-mentioned device, comprising the following steps: S1: Place the metal billet into the extrusion cylinder; S2: Apply axial pressure to the metal billet using an extrusion rod, causing it to be extruded forward through an extrusion die with a specific outlet shape to form a billet with preliminary deformation; S3: A transition ring and a forming core are sequentially and coaxially arranged outside the outlet end of the extrusion die; the front end of the billet extruded from the extrusion die contacts the forming core after passing through the transition ring; S4: Under the action of axial thrust, the extruded preform undergoes continuous plastic bending and expansion deformation on the contour surface of the forming mandrel, realizing a composite deformation of radial expansion and axial extension, and finally conforms to the surface of the forming mandrel to form a continuous preform of the target product. S5: After the blank of the required length of the product is formed, the transition ring is opened to separate and cut the blank located at the transition ring. S6: Move the forming core along the axial direction away from the cut product, remove the product, and then reset the forming core to prepare for the extrusion forming of the next product.

[0033] Furthermore, the forming mandrel can be in a fixed state or a rotating state around its axis in step S4. When the forming mandrel rotates, its function is closer to active spinning, which helps to reduce deformation resistance, improve surface quality and wall thickness uniformity; when the forming mandrel is fixed, its function is mainly to guide and expand the diameter, and the equipment is more simplified.

[0034] Furthermore, the separation and cutting are performed using sawing, shearing, or laser cutting methods.

[0035] Furthermore, the working surface of the forming core mold is a conical surface, a curved surface, a stepped surface, or a combination thereof, and its shape matches the inner cavity shape of the product.

[0036] Furthermore, the outlet shape of the extrusion die is annular to extrude tubular blanks; or it is solid in cross-section to extrude solid bar stock, which is then expanded into a hollow part on the forming mandrel.

[0037] Furthermore, lubrication is applied to the inner surface of the extrusion cylinder, the inner surface of the extrusion die, the inner surface of the transition ring, or the outer surface of the forming core mold.

[0038] The present invention also provides a metal product produced by the above method. The product is an axisymmetric rotating body part or an asymmetrical irregular part with variable cross-section characteristics, which is integrally formed by extrusion and expansion and then cut and separated.

[0039] Furthermore, the product is any one of the following: tapered part, variable diameter pipe fitting, flanged cylindrical part, stepped cylindrical part, or corrugated pipe fitting.

[0040] Example 1: Production of high-strength aluminum alloy conical shells (core mold rotation mode) like Figure 1 As shown, the forming core mold 6 is frustoconical in shape and is connected to the core mold base 7 via a main shaft. Under the action of the control system 12, it can both rotate and move axially.

[0041] A homogenized 6061 aluminum alloy round ingot is placed as billet 3 into a preheated extrusion cylinder 2. The extrusion rod 1 advances at a constant speed, and the billet 3 is extruded into a thick-walled tubular billet through the extrusion die 4 (annular die). The front end of the billet passes through a transition ring 5 and then contacts a high-speed rotating conical mandrel 6. Under the frictional drive and axial thrust of the rotating mandrel 6, the extruded tubular billet undergoes spin forming and expansion on the conical surface of the mandrel 6, forming a continuous conical billet 9. When the billet 9 reaches the predetermined length, the transition ring 5 opens, and the cutting system 10 (such as a flying saw) is activated to cut it off from the transition ring 5. Subsequently, the translation mechanism 8 moves the mandrel 6 forward, causing the product 11 to separate from the mandrel 6. After the product 11 is removed, the mandrel 6 is reset, and the next cycle begins.

[0042] Example 2: Production of large-diameter copper flared-mouth pipe fittings (core mold fixing mode) This embodiment uses a fixed cone-shaped core mold 6.

[0043] Using a copper ingot as the billet 3, the extrusion die 4 has an annular outlet. Under axial thrust, the extruded tubular billet passes through a transition ring 5 and is forced to bend and expand on the conical surface of a fixed mandrel 6, which has a lubricated outer surface, similar to "upsetting to expand the bell mouth," forming a continuous conical tubular billet 9. This process requires no rotary drive, simplifying the equipment. A sawing process 10 is used for fixed-length separation, and a translation mechanism 8 moves the mandrel 6 to remove the product 11, enabling cyclic production. This method is particularly suitable for non-ferrous metals with good plasticity.

[0044] Example 3: Production of stainless steel corrugated pipes Replace the forming core mold 6 with a non-circular core mold (rotatable or fixed) with a periodic wave profile on the surface.

[0045] The tubular billet extruded from the stainless steel casting 3 is expanded on this shaped mandrel 6 to form a continuous corrugated tube blank 9. Individual corrugated tube products 11 can be obtained by precise fixed-length sawing. This method is particularly suitable for manufacturing thick-walled, high-performance metal corrugated tubes.

[0046] In summary, this invention provides a metal extrusion forming apparatus, method, and product based on a combination of extrusion and spin-expansion. The apparatus includes an extrusion system, an expansion forming system, a transition ring, a cutting system, and a control system. The core of the method is as follows: after a metal billet is extruded forward through an extrusion die, it is immediately expanded and extended on the surface of a coaxially arranged forming mandrel to form a continuous product billet; individual products are separated by fixed-length cutting, and the mandrel is moved to remove the products, achieving cyclic production. The forming mandrel can be fixed or rotated. This invention realizes short-process, near-net-shape, semi-continuous production from billets to complex parts (such as conical parts, bellows, etc.), combining the advantages of high performance, high efficiency, and low cost, representing a significant innovation in traditional spinning technology. Therefore, the "extrusion forming" technology disclosed in this invention, by designing forming mandrels with corresponding profiles, can directly produce high-performance metal products from cast billets, including but not limited to the following shapes: tapered parts, variable cross-section pipes (narrowing pipes, flared pipes), irregular cylindrical parts (flared cylinders), stepped cylindrical parts, and special contour parts (parabolic shells, spherical head near-net-shape billets, corrugated pipes), etc. This demonstrates the versatility and strong potential of this invention as a novel basic plastic processing technology.

[0047] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0048] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0049] Through the above description of the embodiments, those skilled in the art can clearly understand that the above implementation methods can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0050] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A metal extrusion forming apparatus, characterized in that, Includes extrusion system, expansion forming system, transition ring, cutting system and control system; The extrusion system includes an extrusion rod, an extrusion cylinder, and an extrusion die installed at the front end of the extrusion cylinder; The expansion forming system includes a forming core die coaxially disposed in front of the extrusion die outlet, a core die holder for mounting and fixing or driving the forming core die to rotate, and a translation mechanism for driving the core die holder to move axially. The transition ring is positioned between the extrusion die outlet and the forming core die so that it can be opened to facilitate the cutting of the extruded billet. The cutting system is installed next to the transition ring and is used to cut the billet extruded at the transition ring; The control system is used to coordinate and control the advancement of the extrusion rod, the movement of the forming mandrel, the opening and closing of the transition ring, and the operation of the cutting system.

2. The apparatus according to claim 1, characterized in that, The expansion forming system also includes a rotary drive mechanism for driving the forming core mold to rotate.

3. The apparatus according to claim 1, characterized in that, The cutting system is a flying saw, hydraulic shears, or laser cutting head.

4. A metal extrusion forming method based on the apparatus according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1: Place the metal billet into the extrusion cylinder; S2: Apply axial pressure to the metal billet using an extrusion rod, causing it to be extruded forward through an extrusion die to form a billet with preliminary deformation; S3: Outside the outlet end of the extrusion die, the front end of the extruded billet passes through a coaxially arranged transition ring and then contacts a coaxially arranged forming core die. S4: Under the action of axial thrust, the extruded preform undergoes continuous plastic deformation on the contour surface of the forming mandrel, realizing a composite deformation of radial expansion and axial extension, forming a continuous target product preform. S5: After the blank of the required length of the product is formed, the transition ring is opened to separate and cut the blank located at the transition ring. S6: Move the forming core along the axial direction away from the cut product, remove the product, and then reset the forming core to prepare for the extrusion forming of the next product.

5. The metal extrusion forming method according to claim 4, characterized in that, In step S4, the forming core mold is either in a fixed state or in a state of rotation about its axis.

6. The metal extrusion forming method according to claim 4, characterized in that, The separation and cutting in step S5 is performed by sawing, shearing or laser cutting.

7. The metal extrusion forming method according to claim 4, characterized in that, The working surface of the forming core mold is a conical surface, a curved surface, a stepped surface, or a combination thereof.

8. The metal extrusion forming method according to claim 4, characterized in that, The outlet of the extrusion die is an annular or solid die, which applies lubrication to the inner surface of the extrusion cylinder, the inner surface of the extrusion die, the inner surface of the transition ring, or the outer surface of the forming core die.

9. A metal article produced by the method according to any one of claims 4 to 8, characterized in that, The product is an axisymmetric rotating body part or an asymmetric variable cross-section irregular part that is integrally formed by extrusion and expansion and then cut and separated.

10. The metal article according to claim 9, characterized in that, The product is any one of the following: tapered part, variable diameter pipe fitting, flanged cylindrical part, stepped cylindrical part, or corrugated pipe fitting.

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