Method of forming a bent length of an extruded profile/section of a metal alloy

文档序号：1431483 发布日期：2020-03-17 浏览：30次中文

阅读说明：本技术 形成金属合金的挤出型材/部分的弯曲长度的方法 (Method of forming a bent length of an extruded profile/section of a metal alloy ) 是由周文彬林建国特雷弗·狄恩王礼良于 2018-05-10 设计创作，主要内容包括：一种挤出材料的方法,包括：将材料提供到挤出设备的挤出腔中,其中,所述挤出腔包括挤出孔,并且所述挤出设备包括与所述挤出腔的内部相通的第一压缩元件和第二压缩元件,所述第一压缩元件和所述第二压缩元件能够相对于所述挤出腔独立地移动,移动所述第一压缩元件和所述第二压缩元件中的至少一个以压缩所述挤出腔内的材料,并在穿过所述挤出孔的所述挤出材料中产生速度梯度；以及,通过所述挤出孔挤出所述材料,以使所述速度梯度形成具有弯曲轮廓的挤出物。(A method of extruding a material comprising: providing material into an extrusion chamber of an extrusion apparatus, wherein the extrusion chamber includes an extrusion orifice and the extrusion apparatus includes first and second compression elements in communication with an interior of the extrusion chamber, the first and second compression elements being independently movable relative to the extrusion chamber, moving at least one of the first and second compression elements to compress material within the extrusion chamber and create a velocity gradient in the extruded material passing through the extrusion orifice; and extruding the material through the extrusion orifice such that the velocity gradient forms an extrudate having a curved profile.)

1. A method of extruding a material comprising:

providing a material into an extrusion chamber of an extrusion apparatus, wherein the extrusion chamber comprises an extrusion orifice and the extrusion apparatus comprises a first compression element and a second compression element in communication with an interior of the extrusion chamber, the first compression element and the second compression element being independently movable relative to the extrusion chamber;

moving at least one of the first compression element and the second compression element to compress the material within the extrusion chamber and create a velocity gradient in the extruded material passing through the extrusion orifice; and

extruding the material through the extrusion orifice such that the velocity gradient forms an extrudate having a curved profile.

2. The method of claim 1, comprising moving both the first compression element and the second compression element to compress material within the extrusion chamber.

3. The method of claim 2, comprising moving the first and second compression elements at different speeds.

4. A method according to claim 2 or 3, wherein the first and second compression elements have different cross-sectional areas perpendicular to their direction of movement.

5. The method of any of claims 1-4, wherein moving the first and second compression elements comprises moving the first and second compression elements along a common axis.

6. The method of claim 5, wherein moving the first and second compression elements along a common axis comprises moving the first and second compression elements toward each other in opposite directions along the common axis.

7. The method of claim 5 or 6, wherein a cross-sectional plane of the extrusion orifice is parallel to the common axis such that extruding the material through the extrusion orifice comprises extruding the material through the extrusion orifice substantially perpendicular to the common axis.

8. The method of any of claims 1-4, wherein moving the first and second compression elements comprises: moving the first compression element along a first axis, and moving the second compression element along a second axis different from the first axis.

9. The method of claim 8, wherein the first axis and the second axis are parallel to each other.

10. The method of claim 9, wherein a cross-sectional plane of the extrusion orifice is perpendicular to the first axis and the second axis such that extruding the material through the extrusion orifice comprises extruding the material through the extrusion orifice substantially parallel to the first axis and the second axis.

11. The method of claim 8, wherein the first axis and the second axis are at an angle to each other.

12. The method of claim 11, wherein a cross-sectional plane of the extrusion orifice is perpendicular to a bisector of an angle between the first axis and the second axis, such that extruding the material through the extrusion orifice comprises extruding the material through the extrusion orifice substantially parallel to the bisector of the angle.

13. A method according to any preceding claim, wherein the material is a metal alloy.

14. The method of claim 13, wherein the metal alloy is an aluminum alloy or a magnesium alloy.

15. A method according to any preceding claim, wherein the extrusion orifice is provided by an extrusion die defining the geometry of the orifice.

16. The method of any preceding claim, further comprising providing a guide adjacent the extrusion orifice to control the curvature of the extruded material.

17. The method of any preceding claim, further comprising providing a mandrel in the extrusion chamber opposite the extrusion orifice.

18. The method of claim 17, wherein extruding the material through the extrusion orifice comprises extruding the material to have a hollow cross-section defined by the mandrel and orifice.

19. The method of any preceding claim, further comprising preheating the material prior to providing the material into the extrusion chamber.

20. A method according to any preceding claim, wherein the extrusion chamber is cylindrical.

21. The method of claim 20, wherein the cross-sectional area of the extrusion cavity is greater than the cross-sectional area of the extrusion orifice.

22. An apparatus for extruding material, the apparatus comprising:

an extrusion chamber for receiving an extruded material, the extrusion chamber including an extrusion orifice;

a first compression element and a second compression element in communication with an interior of the extrusion chamber and independently movable relative to the extrusion chamber.

23. The apparatus of claim 22, wherein the first and second compression elements are configured to move simultaneously.

24. The apparatus of claim 23, wherein the first and second compression elements are configured to move at different speeds.

25. The apparatus of claim 23 or 24, wherein the first and second compression elements have different cross-sectional areas perpendicular to their direction of movement.

26. The apparatus of any of claims 22-25, wherein the first and second compression elements are configured to move along a common axis.

27. The apparatus of claim 26, wherein the first and second compression elements are configured to move toward each other in opposite directions along the common axis.

28. Apparatus according to claim 26 or 27, wherein the cross-sectional plane of the extrusion orifice is parallel to the common axis.

29. The apparatus of any one of claims 22-25, wherein the first compression element is configured to move along a first axis and the second compression element is configured to move along a second axis different from the first axis.

30. The apparatus of claim 29, wherein the first axis and the second axis are parallel to each other.

31. The apparatus of claim 30, wherein a cross-sectional plane of the extrusion orifice is perpendicular to the first axis and the second axis.

32. The apparatus of claim 29, wherein the first axis and the second axis are at an angle to each other.

33. The apparatus of claim 32, wherein a cross-sectional plane of the extrusion orifice is perpendicular to a bisector of an angle between the first axis and the second axis.

34. The apparatus of any one of claims 22 to 32, wherein the extruded material is a metal alloy.

35. The apparatus of claim 24, wherein the metal alloy is an aluminum alloy or a magnesium alloy.

36. The apparatus of any one of claims 22 to 35, wherein the extrusion orifice is provided by an extrusion die defining the geometry of the orifice.

37. The apparatus of any one of claims 22 to 36, further comprising a guide adjacent the extrusion orifice to control the curvature of the extruded material.

38. The apparatus of any one of claims 22 to 37, further comprising a mandrel located in the extrusion chamber opposite the extrusion orifice.

39. The apparatus of any one of claims 22 to 38, wherein the extruded material is preheated.

40. The apparatus of any one of claims 22 to 39, wherein the extrusion chamber is cylindrical.

41. The apparatus of claim 40, wherein the cross-sectional area of the extrusion chamber is greater than the cross-sectional area of the extrusion orifice.

42. The method of any of claims 1 to 21, further comprising: varying the speed of movement of the first compression element and/or the second compression element to vary the speed ratio as the material is extruded.

43. The apparatus of any one of claims 22 to 41, wherein the first and/or second compression elements are configured to move at varying speeds.

Technical Field

The present application relates to a method and apparatus for forming curved metal alloy profiles (particularly aluminum alloy profiles having a pre-designed curvature) in a single extrusion-bending process.

Background

Reducing the weight of metal parts used in land, sea and air transportation can reduce fuel consumption and thereby reduce carbon dioxide emissions. Aluminium alloy profiles are widely used in industrial manufacturing as construction elements for producing ultra-light part structures with high profile complexity, comprising: seat tracks, stringers and frames in the aircraft industry, and window frames and Roof rails (Roof rails) in the automotive industry. Primarily because they contribute to the construction of a light, strong and rigid structure. In view of the need to reduce aerodynamic drag and improve aesthetics, there is a great need for the manufacture and use of high precision curved aluminum alloy sections with good adaptability.

There are several widely recognized methods for bending aluminum alloy sections. Generally, they first produce straight profiles by means of profile rolling or extrusion, followed by a subsequent secondary bending process, such as stretch bending, rotary-draw bending, press bending or roll bending (three-roll bending, four-roll bending or six-roll bending). However, these processes have disadvantages because: (i) more than one process is required to obtain a profile with the desired curvature, which greatly reduces manufacturing productivity; (ii) spring back and cross-sectional deformation often occur due to the high external bending strain applied in the secondary bending process; (iii) for the hollow section, various fillers and mandrels are used in the secondary bending process to avoid potential cross-sectional deformation and buckling; (iv) heavy machinery is required because bending the profile requires a large force; and, (v) many hollow profiles cannot be bent if the shell is too thin or the curvature is too large.

The challenge of improving production is to produce curved profiles with precise curvature, non-deformable cross-section and well-defined properties at higher production rates.

Disclosure of Invention

According to an aspect of the present application, there is provided a method of extruding a material, comprising: providing material into an extrusion chamber of an extrusion apparatus, wherein the extrusion chamber includes an extrusion orifice and the extrusion apparatus includes first and second compression elements in communication with an interior of the extrusion chamber, the first and second compression elements being independently movable relative to the extrusion chamber, moving at least one of the first and second compression elements to compress material within the extrusion chamber and create a velocity gradient in the extruded material passing through the extrusion orifice; and extruding the material through the extrusion orifice such that the velocity gradient forms an extrudate having a curved profile.

According to an aspect of the present application, there is provided an apparatus for extruding material, the apparatus comprising: an extrusion chamber for receiving an extruded material, the extrusion chamber including an extrusion orifice; a first compression element and a second compression element in communication with an interior of the extrusion chamber and independently movable relative to the extrusion chamber.

The method may include moving both the first compression element and the second compression element to compress the material within the extrusion chamber. The method may include moving the first compression element and the second compression element at different speeds.

Moving the first and second compression elements may include moving the first and second compression elements along a common axis. Moving the first and second compression elements along a common axis may include moving the first and second compression elements toward each other in opposite directions along the common axis. A cross-sectional plane of the extrusion orifice may be parallel to the common axis such that extruding the material through the extrusion orifice includes extruding the material through the extrusion orifice substantially perpendicular to the common axis.

Moving the first and second compression elements may comprise: moving the first compression element along a first axis, and moving the second compression element along a second axis different from the first axis. The first axis and the second axis may be parallel to each other. A cross-sectional plane of the extrusion orifice may be perpendicular to the first axis and the second axis such that extruding the material through the extrusion orifice includes extruding the material through the extrusion orifice substantially parallel to the first axis and the second axis.

The first axis and the second axis may be at an angle to each other. A cross-sectional plane of the extrusion orifice may be perpendicular to a bisector of an angle between the first axis and the second axis such that extruding the material through the extrusion orifice includes extruding the material through the extrusion orifice substantially parallel to the bisector of the angle.

The method may further comprise providing a guide adjacent to the extrusion orifice to control the curvature of the extruded material. The method may further include providing a mandrel in the extrusion chamber opposite the extrusion orifice. Extruding the material through the extrusion orifice may include extruding a material having a hollow cross-section defined by the mandrel and orifice. A cross-sectional plane of the mandrel defining a hollow cross-section of the extruded material may be parallel to a cross-sectional plane of the extrusion orifice.

The method may further comprise preheating the material prior to providing the material into the extrusion chamber.

The first compression element and the second compression element may be configured to move simultaneously. The first compression element and the second compression element may be configured to move at different speeds. The first compression element and the second compression element may have different cross-sectional areas perpendicular to their direction of movement.

The first and second compression elements may be configured to move along a common axis. The first and second compression elements may be configured to move toward each other in opposite directions along the common axis. The cross-sectional plane of the extrusion orifice may be parallel to the common axis.

The first compression element may be configured to move along a first axis and the second compression element may be configured to move along a second axis different from the first axis. The first axis and the second axis may be parallel to each other. A cross-sectional plane of the extrusion orifice may be perpendicular to the first axis and the second axis.

The extruded material may be a metal alloy. The metal alloy may be an aluminum alloy or a magnesium alloy. The extrusion orifice may be provided by an extrusion die that defines the geometry of the orifice.

The apparatus may further comprise a guide adjacent to the extrusion orifice to control the curvature of the extruded material. The apparatus may also include a mandrel positioned in the extrusion chamber opposite the extrusion orifice.

The extruded material may be preheated. The extrusion chamber may be cylindrical. The cross-sectional area of the extrusion chamber may be greater than the cross-sectional area of the extrusion orifice.

According to the present application, there is provided a method of forming a curved metal alloy profile, comprising:

(i) providing a lateral extrusion arrangement, a forward extrusion arrangement, or an angled extrusion arrangement;

(ii) preheating a metal alloy billet and then conveying it into an extrusion vessel for hot extrusion; alternatively, the unheated metal alloy billet is directly transferred to an extrusion vessel for cold extrusion;

(iii) pressing the metal alloy billet against an extrusion die and through a die opening by simultaneously applying pressure to two extrusion pads (Dummy blocks) through respective two punches; and

(iv) the speeds of the two punches are adjusted so as to form a speed gradient through the die orifice and produce a curved profile of the long extruded section.

It has the following advantages:

(i) resulting in a curved profile without defects such as cross-sectional deformation or thinning, spring back, wrinkling and folding. Bending is inherent to the process itself, based on internal differential material flow rather than external bending forces.

(ii) For cold extrusion, profiles with ultra-fine grain size are formed and thus the mechanical properties are improved due to Severe Plastic Deformation (SPD) caused by shear stress in the cross-deformed region of the container.

(iii) The profile with adjustable arbitrary curvature is formed in one extrusion-bending process, so that the manufacturing efficiency is greatly improved; and

(iv) no filler or additional heavy machinery is required in the bending process, which greatly reduces the production cost.

Drawings

Exemplary embodiments of the present application will now be described with reference to the accompanying drawings, in which:

fig. 1a is a schematic representation of an extrusion apparatus known in the art;

FIG. 1b is a schematic representation of another extrusion apparatus known in the art;

FIG. 2 is a schematic representation of an extrusion apparatus according to an embodiment;

FIG. 3a is a schematic representation of another extrusion apparatus according to an embodiment;

FIG. 3b is a cross-sectional view taken along line m-m in FIG. 3 a;

FIG. 4 is a schematic illustration of yet another extrusion apparatus according to an embodiment;

fig. 5 is a schematic illustration of the orientation of the first, second and third axes of an extrusion apparatus according to an embodiment.

Like reference numerals refer to like parts throughout the specification and drawings.

Detailed Description

Figure 1a shows an extrusion apparatus known in the art. The cylindrical extrusion chamber 102 has two open ends 104 and 106. An extrusion die 108 having a designed orifice 110 is mounted at the first open end 104. The geometry of the orifice 110 is designed to form the extruded material into a selected shape. A hot or cold billet 112 is placed into the extrusion chamber 102 from the second open end 106.

A punch 114 is positioned at the second open end 106. Its working surface 116 will typically be protected by a squeeze pad 118. The ram 114 together with the pressing pad 118 act as a compression element and are operated at a speed v₁Moving along the extrusion chamber 102, the billet 112 is pushed through the die orifice 110, thereby producing a straight extrudate 120.

Fig. 1b shows another extrusion device known in the art. In this case, the extrusion chamber 130 has an L-shaped cross section, rather than a straight cylindrical shape. In this way, the blank 132 is pushed along the straight portion 134 to form a straight extrudate 136. The straight portion 134 has a sufficient length to ensure that the extrudate 136 is formed straight.

Once a straight extrudate 120 or 136 is produced, a bending process (e.g., stretch bending, rotary draw bending, press bending, or roll bending) is used to form the curved piece. However, forming the curved portion of the extrudate in this manner has disadvantages as described above, such as: reduced manufacturing productivity, spring back, cross-sectional deformation, and the need for various fillers, mandrels, and heavy machinery.

Fig. 2 shows an extrusion apparatus 200 according to the present application. The cylindrical extrusion chamber 202 has two open ends 204 and 206. A hot or cold billet 208 is placed into the extrusion chamber 202 from the first open end 204 and/or the second open end 206. For example, the aluminum alloy billet may be preheated to 350-. A first punch 210 is positioned at the first open end 204. A second punch 212 is positioned at second open end 206. The working surfaces 214 and 216 of the first punch 210 and the second punch 212, respectively, are protected by respective pressing pads 218 and 220. An extrusion die 222 having a defined orifice 224 is mounted in the side wall of the extrusion chamber 202.

The first punch 210 and the pressing pad 218 together serve as a first compression element, and the second punch 212 and the pressing pad 220 together serve as a second compression element. Those skilled in the art will appreciate that these compression elements may be replaced by other suitable compression devices. The first compression element and the second compression element may be independently movable relative to the extrusion chamber 202. This allows the profile of the extrudate to be controlled, particularly with respect to its curvature, as described below.

In operation, pressure is applied to both of the compression pads 218 and 220 simultaneously by the respective two punches 210 and 212. The velocity of the first punch 210 is v₁The speed of the second punch 212 is v₂. As the punches move toward each other, the billet 208 is pushed laterally out of the extrusion cavity 202 through the die holes 224. The discharge direction of the punch is perpendicular to the moving direction of the punch.

To produce a curved extrudate, the mass flow Rate (Rate of flow) provided by each compression element may be adjusted. In one embodiment, the speed of the punches 210 and 212 may be adjusted to provide a curved extrudate. When one punch moves faster than the other, a flow velocity gradient through the die bore 224 is created. Thus, the extruded profile is bent towards the side of the extrusion chamber 202 having the lower extrusion speed. In fig. 2, the speed v of the first punch 210₁Greater than the speed v of second punch 212₂. Thus, the extrudate 226 is bent toward the second open end 206. In another embodiment, the area of the first compression pad 218 is greater than the area of the second compression pad 220. In this case, the extruded profile will bend downward as shown in FIG. 2, even at v₁＝v₂The same is true in the case of (2).

The key is to control the amount of material flowing into the die outlet 222 per unit time, which may be expressed as Q ═ Sv. Here, S is the cross-sectional area and v is the velocity. Thus, the velocity v is increased₁And/or the area of the first crush pad 218, may result in moreThe material flows into the upper side (as compared to the lower side) of the die exit 222.

By using two extrusion punches to create a controlled flow velocity gradient through the exit of the extrusion die orifice, the extrusion and bending operations can be performed simultaneously. This eliminates the need for subsequent processing of the straight extrusion to provide curvature, overcoming the problems described above.

By adjusting the speed ratio of the two punches (or more generally, the material flow rate Q), the curvature of the extrudate 226 can be adjusted. If the velocity ratio is defined as v₂/v₁Then a lower velocity ratio tends to increase the material flow velocity gradient at the die exit and result in a greater curvature. When the speed ratio is less than 1/3, the bending curvature increases significantly with decreasing speed ratio. The lower punch 212 will produce the maximum curvature when the speed is zero. The speed ratio can be varied during extrusion. This will enable the curvature of the extrudate 226 to change as extrusion progresses, allowing for more complex extrusion.

In addition, the relative cross-sectional areas of extrusion cavity 202 and orifice 224 may be adjusted to vary the curvature. The extrusion ratio is defined as the ratio of the cross-sectional area of the billet to the cross-sectional area of the extruded profile. These areas are controlled by adjusting the cross-sectional areas of the extrusion chamber 202 and the extrusion orifice 224, respectively. For extrusion of a solid round bar, the extrusion ratio may be defined as the square of the ratio of the diameter of the extrusion cavity 202 to the orifice 224. For tubular round extrusion (hollow rod), it can be defined as D₁ ²/(D₂ ²-D₃ ²) Wherein D is₁，D₂，D₃Respectively, the diameter of extrusion chamber 202, bore 224, and a mandrel secured to the inner wall of the extrusion chamber opposite the die exit to define the wall thickness of the tube.

A larger extrusion ratio tends to increase the material flow velocity gradient at the die exit and results in a larger curvature. For a constant diameter extrusion chamber 202, the curvature of the extrudate 226 increases as the diameter of the orifice 224 decreases. Conversely, the curvature of the extrudate 226 decreases as the diameter of the aperture 224 increases. The effect of varying the extrusion ratio is less than the effect of varying the speed ratioEspecially when the speed ratio is greater than 0.5. Below this value, the influence of the extrusion ratio is dependent on the velocity ratio v₂/v₁Is increased.

Fig. 3a shows an alternative extrusion device 300 according to the present application. The apparatus 300 is similar to the apparatus 100 of FIG. 1a, except that two adjacent punches are used instead of one single punch. The cylindrical extrusion chamber 302 has two open ends 304 and 306. A hot or cold billet 308 is placed into the extrusion chamber 302 from the second open end 306. A first punch 310 and a second punch 312 are positioned adjacent to each other at the second open end 306. The working faces 314 and 316 of the first punch 310 and the second punch 312, respectively, are protected by pressing pads 318 and 320, respectively. An extrusion die 322 having a designed orifice 324 is mounted at the first open end 304.

The length of the first compression pad 318 is shown to be longer than the length of the second compression pad 320. In the case where the second pressing pad 320 moves faster than the first pressing pad 318, the second pressing pad 320 may completely pass over the first pressing pad 318. In this case, the billet 308 may flow out of the extrusion chamber 302 from the gap between the first extrusion pad 318 and the second extrusion pad 320. This can be alleviated by implementing a longer profile first press pad.

In operation, pressure is applied to the two compression pads 318 and 320 simultaneously by the respective two punches 310 and 312. The speed of the first punch 310 is v₁The speed of the second punch 312 is v₂. As the punches move alongside each other, the billet 308 is pushed out of the extrusion chamber 302 through the die holes 324.

In the embodiment described above, when one punch moves faster than the other, a flow velocity gradient through the die holes 324 is created. Thus, the extruded profile is curved toward the side of the extrusion chamber 302 having the lower extrusion speed. In fig. 3a, the velocity v of the first punch 310₁Greater than the speed v of the second punch 312₂. Thus, extrudate 326 is bent towards the side of cylindrical extrusion chamber 302 having second punch 312. Additionally or alternatively, the area of the squeeze pads 318 and 320 may be adjusted to provide this effect. FIG. 3b shows the tool in a direction perpendicular to their direction of movementThere are different cross-sectional areas of the crush pads 318 and 320.

Fig. 4 shows a further alternative extrusion apparatus 400 according to the present application. The apparatus includes a Y-shaped extrusion chamber 402 having a first aperture 404, a second aperture 405 and a central reservoir 406. The first aperture 404 and the second aperture 405 are positioned at an angle to each other and converge to meet the central receptacle 406 to form a Y-shape. Each of the first aperture 404, the second aperture 405 and the central receptacle 406 has an open end opposite the convergence point.

A hot or cold first billet 407 is placed into the open end of the first aperture 404. A hot or cold second blank 408 is placed into the open end of the second aperture 405. A first punch 410 is positioned at the open end of the first bore 404. A second punch 412 is positioned at the open end of the second bore 405. The working surfaces 414 and 416 of the first punch 410 and the second punch 412, respectively, are protected by respective pressing pads 418 and 420. An extrusion die 422 having a designed orifice 424 is mounted at the open end of the central vessel 406.

In operation, pressure is applied to the two squeeze pads 418 and 420 simultaneously by the respective two punches 410 and 412. The velocity of the first punch 410 is v₁The speed of the second punch 412 is v₂. As the punches move toward each other, the billet 408 is pushed out of the extrusion cavity 402 from the side through the die holes 424.

In the embodiment described above, a flow velocity gradient through the die bore 424 is created when one punch moves faster than the other. Thus, the extruded profile is curved toward the side of the extrusion chamber 302 having the lower extrusion speed. In fig. 4, the speed v of the first punch 410₁Greater than the speed v of the second punch 412₂. Accordingly, the extrudate 426 is bent toward the second orifice 405. Additionally or alternatively, the area of the crush pads 418 and 420 may be adjusted to provide this effect.

In the above embodiments described with reference to fig. 2-4, the first and second compression elements may be positioned at an angle α, as shown in fig. 5, the first and second axes correspond to the first and second compression elements, and the third axis bisects the angle between the first and second axes and corresponds to the direction of extrusion from the die orifice.

The first axis is at an angle β of 180 ° - α/2 to the direction of flow of extrudate from the extrusion apparatus (i.e., the third axis) and likewise, the second axis is at an angle β of 180 ° - α/2 to the third axis.

The shear stress applied at the intersection between the first axis and the third axis (and, likewise, at the intersection between the second axis and the third axis) causes Severe Plastic Deformation (SPD) of the billet at the intersection of the axes.

The first and second axes may be oriented at an angle 0 ° ≦ α ≦ 360 °. the extrusion apparatus schematically shown in fig. 2 corresponds to an angle α ≦ 180 °. the extrusion apparatus schematically shown in fig. 3 corresponds to an angle α ≦ 0 °. the extrusion apparatus schematically shown in fig. 4 may have any angle from 0 ° to 360 °.

By using any of the embodiments described above, a curved portion with an undeformed cross-section can be obtained by using an asymmetric flow in the extrusion die. Since it is a natural bending process based on internal dissimilar material flow rather than external bending forces, defects such as cross-sectional deformation and thinning are avoided. The extrusion process and the bending process are combined into one process, thereby avoiding the complexity of additional external bending equipment.

The effect of this is the speed v of the compression element (formed by the punch and the pressing pad)₁And v₂Is implemented by the variation of (1). However, in some embodiments, the compression elements may move at the same speed, with the extrusion orifices passing therethroughIs a function of the geometric characteristics (e.g., one press pad/compression element has a larger surface area than the other press pad/compression element). In other embodiments, the combination of the geometry characteristics and the velocity of the compression element may result in a desired velocity gradient at the extrusion orifice.

In any of the embodiments described above, a guide external to die orifice 224 may be employed to ensure accurate curve accuracy. Any of the embodiments described above may be used for extrusion of solid rods or tubes. For hollow extrusion, the mandrel may be secured to an inner wall of the extrusion chamber opposite the die exit. The size of the mandrel relative to the size of the die hole will define the wall thickness of the extruded tube. The curvature of the tube decreases as the wall thickness of the tube increases. However, the effect of wall thickness on curvature is small compared to the effect of velocity ratio on curvature. In addition, the extrusion of round tubes also shows a similar tendency to that of the extrusion of round rods described above.

Any of the above embodiments may be used to produce curved profiles of any material that can be manufactured by conventional extrusion processes. The main application is the extrusion of metal alloys. These include aluminum, magnesium, copper, steel, titanium and nickel. The system has been described in connection with aluminum, since aluminum is the most commercially viable application, but its implementation is not limited to only that associated with aluminum.

Any of the above embodiments may be used for hot extrusion or cold extrusion. In the case of hot extrusion, the hot metal billet used may be virtually any metal alloy billet that is heated to the temperatures typically used in hot extrusion processes. True Temperature Technology ("3T") equipment is used to record the exit Temperature of the extruded part. The exit temperature is maintained at a reasonable temperature for Solution heat treatment ("SHT") by adjusting the extrusion speeds of the two punches while keeping the extrusion speed ratio constant. The target exit temperature of the extruded part is determined by the metal alloy. For 6xxx series aluminum alloys, temperatures in the range of 500 ℃ > 530 ℃ for the solution heat treatment should be achieved at the die exit to achieve optimum mechanical properties. The extruded part may be quenched after SHT using water, spray or air cooling depending on the alloy and final mechanical property requirements.

In the foregoing, although fig. 2-4 describe embodiments including two compression elements, it will be appreciated that other compression elements may be included to control curvature in other planes.

Other embodiments of the present application are listed in the following items:

1. a method of extruding a material comprising:

moving at least one of the first compression element and the second compression element to compress material within the extrusion chamber and create a velocity gradient in the extruded material passing through the extrusion orifice; and