Carbon fiber winding prestress extrusion die

Abstract

The invention discloses a carbon fiber winding prestress extrusion die which comprises an inner die, a lining supporting ring and a split type prestress ring, the lining supporting ring is arranged on the outer side of the inner die and is in clearance fit with the inner die, and the split type prestress ring is arranged on the outer side of the lining supporting ring and is in clearance fit with the inner die. A carbon fiber winding layer is arranged on the outer side of the split type prestress ring. Compared with the prior art, the carbon fiber winding prestress is adopted to replace a traditional steel wire, the manufacturing and assembling difficulty of the large-size prestress mold structure is remarkably reduced, and the overall performance of the mold is improved. Due to the excellent mechanical property, anti-fatigue property, thermal stability and high-temperature stability of the carbon fibers, the mold structure can stably work for a long time in a high-stress and high-temperature environment, the fatigue cracking problem of traditional materials is avoided, and the service life of the mold is remarkably prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of prestressed extrusion dies, in particular to a carbon fiber winding prestressed extrusion die. Background Art

[0002] During the metal extrusion process, when the inner mold extrude the blank, the deformation of the blank will cause the inner mold cavity to be subjected to internal pressure. Under the action of this internal pressure, the inner mold cavity usually undergoes elastic deformation, causing the cavity size to change with the change of the internal pressure. In severe cases, fatigue cracking may occur in the inner mold. For this reason, a multi-layer composite structure of a prestressed ring or a stress ring is often used in the prior art to protect the inner mold. The specific method is to press the inner mold into the prestressed ring by cold or hot installation, and apply tangential compressive prestress. This prestress can effectively offset the tangential tensile stress generated by the inner mold under the action of internal pressure, eliminate tangential strain, and then improve the bearing capacity of the inner mold and prevent cracking. In the production of small and medium-sized metal extrusions, the above structure has been widely used. However, for the extrusion forming of large workpieces, the increase in the size specifications of the inner mold and the prestressed ring will bring both technical and economic difficulties to the realization of processing accuracy and press-fit assembly.

[0003] Patent CN201940433U discloses a wire-wound prestressed extrusion die structure, which reduces the manufacturing cost and assembly difficulty of large-size prestressed die structures, can effectively improve the life of the die, prevent the die from failure and cracking, and realize the forming of large extrusion parts.

[0004] However, the traditional wire winding technology has exposed some limitations in the actual production process, especially in terms of precision and strength. Although steel wire (such as 65Mn material) has high strength, it is prone to stress relaxation under high temperature and high pressure environment, resulting in gradual failure of prestress, thus affecting the precision and performance of the mold. The rigidity of steel wire is low, especially when subjected to high internal pressure, it may not be able to effectively offset the elastic deformation of the inner mold, thereby affecting the dimensional accuracy and surface quality of the formed part. In addition, the high density of steel wire increases the overall weight of the mold and increases the load on the production equipment. In the design and assembly of large molds, the use of steel wire also brings about an increase in technical difficulty and economic cost. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a carbon fiber winding prestressed extrusion die, which uses carbon fiber winding to compensate for the stress and strain generated by the forming inner die during operation, reduce the stress concentration and fatigue damage of the die, and thus improve the deformation resistance and service life of the die. Compared with traditional metal materials, carbon fiber has higher strength, can maintain excellent performance under high loads, and significantly improves the stability and forming accuracy of the die.

[0006] To achieve this technical purpose, the present invention adopts the following scheme: A carbon fiber winding prestressed extrusion die comprises an inner die, an inner liner support ring and a petal prestressed ring. The inner liner support ring is arranged on the outer side of the inner die, and a small clearance is adopted between the inner liner support ring and the inner die. The petal prestressed ring is arranged on the outer side of the inner liner support ring, and a carbon fiber winding layer is arranged on the outer side of the petal prestressed ring.

[0007] Compared with the prior art, the present invention has the following beneficial effects: The use of carbon fiber winding prestressing instead of traditional steel wire not only significantly reduces the difficulty of manufacturing and assembling large-size prestressed mold structures, but also improves the overall performance of the mold. The excellent mechanical properties, fatigue resistance, thermal stability and high-temperature stability of carbon fiber enable the mold structure to work stably for a long time in a high-stress, high-temperature environment, avoiding the fatigue cracking problem of traditional materials and significantly extending the service life of the mold. This technical solution not only improves the accuracy and stability of the mold, but also reduces the cost of the production enterprise, meeting the production needs of large-scale, high-precision metal extrusion parts.

[0008] Furthermore, a first vertical slot is provided on the outer side of the inner mold, and a second vertical slot is provided on the outer side of the liner support ring, which are used to control the vertical position when the mold is assembled.

[0009] Furthermore, the split-petal prestressed ring is composed of 2 to 8 parts, preferably four parts, six parts or eight parts, and the parts are centrally symmetrically arranged.

[0010] Furthermore, a positioning key is provided at the bottom of the split-petal prestressed ring.

[0011] Furthermore, a groove is arranged on the outer side of the split-petal prestressed ring, and the carbon fiber winding layer is arranged in the groove.

[0012] Furthermore, the carbon fiber winding layer adopts carbon fiber T700. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is an elevation view of a carbon fiber winding prestressed extrusion die according to an embodiment of the present invention; Figure 2 This is a cross-sectional view of the carbon fiber winding prestressed extrusion die according to an embodiment of the present invention; Figure 3 This is a cross-sectional view of a carbon fiber winding prestressed extrusion die according to an embodiment of the present invention; Marked in the figure are: 1. inner mold; 2. liner support ring; 3. petal prestressed ring; 4. carbon fiber winding layer; 5. positioning key; 6. first vertical slot; 7. second vertical slot. DETAILED DESCRIPTION

[0014] In order to fully understand the purpose, features and effects of the present invention, the present invention is described in detail through the following specific implementation methods, but the present invention is not limited thereto.

[0015] See also Figures 1 to 3 The present invention provides a carbon fiber winding prestressed extrusion die, comprising an inner die 1, an inner liner support ring 2, a petal prestressed ring 3 and a carbon fiber winding layer 4 arranged from the inside to the outside. The tops of the inner die 1 and the inner liner support ring 2 are provided with protrusions for die assembly; the petal prestressed ring 3 is composed of 2 to 8 parts, each part is centrally symmetrically arranged, and a positioning key 5 is arranged at the bottom of the petal prestressed ring 3 for positioning each part of the petal prestressed ring 3. A groove is arranged on the outer side of the petal prestressed ring 3, and the carbon fiber winding layer 4 is arranged in the groove. The carbon fiber winding layer 4 uses carbon fiber (T700).

[0016] In a specific embodiment, the inner mold 1 and the inner liner support ring 2 are assembled through a small gap to control the horizontal position. The outer side of the inner mold 1 is provided with a first vertical slot 6, and the height of the first vertical slot 6 is equal to the height of the inner liner support ring 2. The outer side of the inner liner support ring 2 is provided with a second vertical slot 7, and the height of the second vertical slot 7 is equal to the height of the split-type prestressed ring 3. When the mold is assembled, the vertical position is controlled by the vertical slots set on the inner mold 1 and the inner liner support ring 2. The multiple components of the split-type prestressed ring 3 present a central symmetrical structure and fit tightly around the outer surface of the inner liner support ring 2. The position of the mold is accurately positioned by several positioning keys 5. A certain gap is maintained between the various components of the split-type prestressed ring 3. Subsequently, a carbon fiber winding machine is used to pre-tighten the outer surface of the split-type prestressed ring 3 with carbon fiber to form a carbon fiber winding layer 4.

[0017] The carbon fiber winding layer 4 can provide a uniform and efficient external prestressing force for the split-type prestressed ring 3. Through the high-strength characteristics of carbon fiber, the carbon fiber winding layer 4 can not only effectively eliminate the gaps between the components of the split-type prestressed ring 3, but also enable it to apply uniform prestress to the liner support ring 2, ensuring that the gap between the inner mold 1 and the liner support ring 2 is completely eliminated, and can remain stable under a greater pressure load than steel wire, and has good stability. In addition, the low thermal expansion coefficient and high-temperature stability of carbon fiber materials enable the carbon fiber winding layer 4 to maintain high strength and stability in high-temperature environments, thereby avoiding prestress relaxation caused by temperature changes. The anti-fatigue properties of carbon fiber also ensure that even during long-term use, the carbon fiber winding layer 4 can still maintain a relatively stable prestress, preventing deformation, cracks and other problems in the mold.

[0018] The carbon fiber winding layer 4 not only effectively improves the function of the split prestressed ring 3, but also further protects the inner mold 1 and avoids cracking by eliminating the possible tangential strain of the inner mold 1, thereby significantly improving the load-bearing capacity and service life of the inner mold 1.

[0019] Compared with the prior art, the present invention has the following improvements and advantages: 1. Reduce the difficulty of manufacturing and assembly: Traditional large-size prestressed mold structures usually use steel wire (such as 65Mn steel wire) for prestressed winding, which not only increases the weight of the material, but also makes the assembly and fastening of the steel wire more complicated. The present invention uses carbon fiber winding instead of steel wire, which not only effectively reduces the weight of the material, but also simplifies the assembly process, which can significantly improve the construction efficiency and safety. In addition, carbon fiber is in a state of oversupply. With the further improvement of its manufacturing process, it is expected to achieve further reduction in material costs.

[0020] 2. Comparison of specific strength and specific stiffness: Carbon fiber (T700) has excellent specific strength and specific stiffness. Compared with the commonly used 65Mn steel wire, the tensile strength of carbon fiber reaches about 3500 MPa and the elastic modulus is 230 GPa, while the tensile strength of 65Mn steel wire is about 1500 MPa and the elastic modulus is 200 GPa. Therefore, carbon fiber has higher load-bearing capacity and better rigidity performance, and can more effectively maintain the prestressed state when facing large loads. Under high working load conditions, the elastic deformation of the carbon fiber winding prestressed mold cavity is small, and the products produced have higher dimensional accuracy and are more suitable for precision plastic forming of metals. See Table 1 for specific performance indicators.

[0021] Table 1 Comparison of mechanical properties of steel wire and carbon fiber

[0022] 3. Anti-fatigue performance: Carbon fiber has high anti-fatigue strength, can stably maintain the prestressing effect under high temperature and high pressure environment, and effectively prevent stress relaxation. Compared with traditional steel wire, carbon fiber has better fatigue performance under long-term load or high stress environment, reducing the risk of cracks or failure of molds due to fatigue.

[0023] 4. Lightweight and high efficiency: The density of carbon fiber is only 1.6 g / cm³, which is much lower than 7.8 g / cm³ of 65Mn steel wire. Therefore, the use of carbon fiber winding can not only significantly reduce the overall weight of the mold, but also reduce the load of the mold during use, thereby reducing wear on the equipment and increasing the service life of the mold.

[0024] 5. High temperature stability: Carbon fiber materials have excellent high temperature stability and can maintain high strength and stiffness in high temperature environments, ensuring that the prestressing effect does not relax due to high temperatures. This is particularly important in the metal extrusion process, which can improve the bearing capacity and processing accuracy of the mold.

[0025] 6. Low thermal expansion coefficient: Carbon fiber (T700) has significant advantages in thermal stability compared to traditional steel wire materials (such as 65Mn steel wire). Specifically, the thermal stability of carbon fiber is as follows: Carbon fiber (T700) has a very low thermal expansion coefficient of about 0.5×10 -6 / ℃, which means that its dimensional change when the temperature changes is very small, which can effectively maintain the accuracy of the mold. In contrast, the thermal expansion coefficient of 65Mn steel wire is 11.5×10⁻ 6 / ℃, which means that in a high temperature environment, the size of the steel wire changes greatly, which may lead to prestress relaxation or mold failure. The maximum operating temperature of carbon fiber material (T700) can reach 300°C, while the maximum operating temperature of 65Mn steel wire is usually 200°C. Above this temperature, the strength and stiffness of the steel wire will decrease significantly, and stress relaxation is likely to occur, affecting the performance and service life of the mold. For specific thermal expansion coefficients, see Table 2.

[0026] Table 2 Comparison of thermal expansion coefficients of steel wire and carbon fiber

[0027] As can be seen from the table above, carbon fiber (T700) has a significant advantage in thermal stability. The low thermal expansion coefficient and high operating temperature range of carbon fiber enable it to work stably for a long time in a high temperature environment without producing thermal expansion and contraction effects, which is crucial for the stability of the mold in high temperature processing environments such as metal extrusion.

[0028] In summary, the use of carbon fiber winding prestressing instead of traditional steel wire not only significantly reduces the difficulty of manufacturing and assembling large-size prestressed mold structures, but also improves the overall performance of the mold. The excellent mechanical properties, fatigue resistance, thermal stability and high-temperature stability of carbon fiber enable the mold structure to work stably for a long time in a high-stress, high-temperature environment, avoiding the fatigue cracking problem of traditional materials and significantly extending the service life of the mold. This technical solution not only improves the accuracy and stability of the mold, but also reduces the cost of the production enterprise, meeting the production needs of large-scale, high-precision metal extrusion parts.

[0029] Finally, it should be noted that the above are only preferred embodiments of the present invention. Of course, those skilled in the art can make changes and modifications to the present invention. If these modifications and variations fall within the scope of the claims of the present invention and their equivalent technologies, they should be considered to be within the scope of protection of the present invention.

Claims

1. A carbon fiber winding prestressed extrusion die, comprising an inner die (1), an inner liner support ring (2) and a split-type prestressed ring (3), characterized in that: The liner support ring (2) is arranged on the outside of the inner mold (1), and a clearance fit is adopted between the liner support ring (2) and the inner mold (1). The petal-type prestressed ring (3) is arranged on the outside of the liner support ring (2), and a carbon fiber winding layer (4) is arranged on the outside of the petal-type prestressed ring (3).

2. The carbon fiber winding prestressed extrusion die according to claim 1, characterized in that: A first vertical slot (6) is provided on the outer side of the inner mould (1), and a second vertical slot (7) is provided on the outer side of the inner liner support ring (2), which are used to control the position in the vertical direction when the mould is assembled.

3. The carbon fiber winding prestressed extrusion die according to claim 1, characterized in that: The split-type prestressed ring (3) is composed of 2 to 8 parts, and each part is arranged in a centrally symmetrical manner.

4. The carbon fiber winding prestressed extrusion die according to claim 1, characterized in that: A positioning key (5) is provided at the bottom of the split-flap prestressed ring (3).

5. The carbon fiber winding prestressed extrusion die according to claim 1, characterized in that: A groove is arranged on the outer side of the split-type prestressed ring (3), and the carbon fiber winding layer (4) is arranged in the groove.

6. The carbon fiber winding prestressed extrusion die according to claim 1, characterized in that: The carbon fiber winding layer (4) is made of carbon fiber T700.

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