Extrusion die for titanium alloy bar

Abstract

The utility model discloses an extrusion die for a titanium alloy bar. The extrusion die comprises a charging barrel, a thrust rod, a force transmission block, a base, a stop block and a split conical die, wherein a force application end of the thrust rod extends into the charging barrel from the right side; the force transmission block is arranged in the charging barrel and is positioned between a blank and the force application end of the thrust rod; the guide assembly is connected to the left side of the base and the left side of the check block and used for guiding extruded bars to improve the straightness. The inlet of the working area of the split conical die is a conical surface, and the edge of the inlet of the working area is attached to the inner wall of the charging barrel. According to the utility model, the defect that a plane die is easy to scratch a copper sleeve is overcome, the defects of large single piece, inflexible replacement and high die replacement cost of an integral conical die are overcome, and meanwhile, the problem that a bar formed by extrusion is easy to bend seriously is solved. The hot extrusion die is suitable for being used when titanium alloy bars are produced through the hot extrusion technology, and produced products are high in size precision, good in appearance quality and high in straightness.

Description

Technical Field

[0001] The utility model belongs to the technical field of nonferrous metal processing, and relates to the extrusion molding of titanium alloy bars, in particular to an extrusion die for titanium alloy bars. Background Art

[0002] Titanium alloy bar is a kind of slender parts made of titanium alloy. It has high strength, good corrosion resistance, high heat resistance, low density, and can be processed secondary. It is widely used in aerospace, military, automobile, medical, petrochemical and other fields.

[0003] The main forming processes for titanium alloy bars include open forging, die forging, and hot extrusion. Open forging requires multiple heating cycles, resulting in coarse microstructure and poor surface dimensional accuracy. Die forging produces flash and burrs, making the formed bar prone to cracking. Furthermore, the die investment for long shafts is high, placing high demands on the equipment. Hot extrusion, on the other hand, offers flexible die replacement, allows for large deformation in a single pass, fully exploits the material's plasticity, facilitates the deformation of low-plasticity materials, and is therefore suitable for the hot processing of titanium alloy bars. Consequently, hot extrusion has become the mainstream production process for titanium alloy bars.

[0004] The hot extrusion process of titanium alloy bars includes billet preparation, double jacketing, hot extrusion and other processes. Among them, the extrusion die types used in the hot extrusion process are mainly flat die 9 and integral cone die 12. However, both flat die 9 and integral cone die 12 have certain problems when used, as follows:

[0005] First, the structure of the existing plane mold 9 is as follows Figure 1 As shown, it is combined with the barrel, thrust rod, force transmission block and other components in cooperation with the die base 10 and the die support 11 to form an extrusion die. When used in the hot extrusion process, due to the presence of a long platform at the entrance of the extrusion die working area, the deformation "dead zone" is large, the metal deforms violently, and the copper sleeve wrapped around the surface of the blank is easily torn, resulting in the loss of lubrication, and thus causing cracks in the bar formed by the deformation of the blank.

[0006] Second, the structure of the existing integral cone mold 12 is as follows Figure 2 As shown, it is combined with the barrel, thrust rod, force transmission block and other components in conjunction with the housing 13 to form an extrusion die. When used in the hot extrusion process, because the entire working area entrance of the extrusion die is a conical surface without a platform, the flow velocity difference between the inner and outer surfaces of the blank is reduced, the deformation "dead zone" is minimized, the metal flows smoothly, and the copper sleeve wrapped around the surface of the blank can effectively lubricate it. However, the overall conical die 12 is large in size, heavy in weight, difficult to machine, and inflexible to replace. During use, the sizing area of ​​the extrusion die is subject to high friction, resulting in a high damage rate. Once damaged, the entire die needs to be replaced, which is costly.

[0007] In addition, when the extrusion die formed by the flat die 9 or the integral cone die 12 and other components is used, the extruded rods often have serious bending problems, which makes subsequent correction difficult and requires a large amount of secondary processing. Utility Model Content

[0008] The utility model provides an extrusion die for titanium alloy bars, which aims to solve the shortcomings of flat dies that easily scratch the copper sleeve, overcome the shortcomings of integral cone dies that are heavy, inflexible to replace, and high cost of die replacement, and solve the problem that extruded bars are prone to severe bending, thereby achieving the purpose of improving product quality.

[0009] To achieve the above-mentioned object, the technical solution adopted by the present invention is as follows: an extrusion die for titanium alloy bars, comprising a barrel, a thrust rod with a force-applying end extending into the barrel from the right side, a force transmission block provided in the barrel and located between the blank and the force-applying end of the thrust rod, a base and a stopper assembled on the left side of the barrel, and a split cone die assembled in an inner cavity structure formed by the base and the stopper;

[0010] Also included is a guide assembly connected to the base and the left side of the stopper for guiding the extruded bar material to improve straightness;

[0011] The working area inlet of the split cone mold is a cone surface, and the edge of the working area inlet fits the inner wall of the barrel.

[0012] As a limitation of the present invention, the split cone mold is an annular structure, comprising a mold body and a mold core assembled into one body; the mold body has an assembly cavity adapted to the outer contour of the mold core and a first inlet conical surface connected to the assembly cavity, and the inner contour of the mold core includes a second inlet conical surface, a sizing area and an outlet counter-conical surface;

[0013] The cone angle γ1 of the first inlet cone surface is equal to the cone angle α1 of the second inlet cone surface, and the center lines of the mold body and the mold core are coaxial, so that the working area inlet of the split cone mold formed by the mold body and the mold core is a cone surface.

[0014] As a further limitation of the present invention, in the mold core, the cone angle α1 of the second inlet conical surface is 100-120°, the length of the sizing zone is 10-20 mm, and the cone angle α2 of the outlet counter-conical surface is 10-14°.

[0015] As a further limitation of the present invention, the sizing area of ​​the mold core is cylindrical, and the inner diameter of the sizing area is 1.014 times the outer diameter of the bar.

[0016] As a further limitation of the present invention, the second inlet conical surface of the mold core is connected to the sizing area with a fillet, and the fillet radius is 10 mm.

[0017] As a further limitation of the present invention, the outer contour of the mold core includes a first conical surface and a cylindrical surface; wherein the cone angle β of the first conical surface is 20-26°, and the length l1 is 20-30 mm; the length l2 of the cylindrical surface is 15-28 mm.

[0018] As a further limitation of the present invention, the outer contour of the right section of the mold body is a second conical surface, and the outer contour of the left section is a step surface; wherein the cone angle γ2 of the second conical surface is 60°.

[0019] As another limitation of the present invention, the guide assembly includes a support pad and a guide cylinder; wherein the support pad is a cylindrical structure assembled on the left side of the base, and a plurality of positioning grooves are evenly distributed along the edge of the inner hole on the right end surface of the support pad; the guide cylinder is a cylindrical structure inserted into the inner hole of the support pad, and a plurality of positioning blocks adapted to the positioning grooves are provided on the edge of the right end surface of the guide cylinder;

[0020] The length of the guide cylinder is greater than the length of the support pad, and the diameter of the inner hole of the guide cylinder is equal to the inner diameter of the stop block.

[0021] As a further limitation of the present invention, the stopper is a hollow cylinder, the outer diameter of which is equal to the maximum outer contour of the split cone die, and the inner diameter of which is 10 to 15 mm larger than the outlet end of the split cone die.

[0022] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0023] (1) The present invention designs a new extrusion die for use in the hot extrusion process of titanium alloy bars. It solves the problem that when using a flat die for extrusion, the platform at the entrance forms a deformation "dead zone", which causes the copper sleeve wrapping the blank to be easily scraped off. It also solves the problem that the integral cone die is heavy, bulky, inflexible to replace, and has high die replacement costs. Specifically, the present invention adopts a split cone die design (including a die body and a die core). The split structure is more convenient for processing. After the sizing area is worn, only the die core can be replaced, which is convenient for replacement and maintenance, and can also save expensive materials, thereby reducing the die replacement cost. In addition, the first inlet conical surface of the die body and the second inlet conical surface of the die core in the present invention adopt an equal cone angle design, so that the working area inlet of the split cone die formed by the die body and the die core is a cone surface, and after being assembled in the barrel, the edge of the working area inlet is in contact with the inner wall of the barrel, so that the entire inlet surface has a smooth transition. During hot extrusion, the metal flows smoothly, the copper sleeve wrapping the blank will not be scratched, and it can play a good lubricating role, thereby ensuring product quality.

[0024] (2) The present invention also adds a guide assembly (support pad and guide cylinder) at the discharge end, which can guide the extruded rod material to prevent it from bending, thereby improving the straightness of the discharge material.

[0025] In summary, the present invention has an ingenious structural design. When used in a hot extrusion process, the product produced has high dimensional accuracy, good appearance quality, and high straightness, which can reduce the subsequent finishing work and processing volume, thereby improving the utilization rate of raw materials. The present invention is suitable for use in the production of titanium alloy bars using a hot extrusion process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0027] Figure 1 This is a cross-sectional view of the structural relationship of the plane mold assembly in the background technology of the present utility model;

[0028] Figure 2 A cross-sectional view of the structural relationship of the integral cone mold assembly in the background technology of the present utility model;

[0029] Figure 3 A cross-sectional view showing the structure of an embodiment of the present utility model;

[0030] Figure 4 A cross-sectional view of the structural relationship of the split cone mold assembly in an embodiment of the present utility model;

[0031] Figure 5 This is a cross-sectional view of the structural relationship of the split cone mold in the embodiment of the utility model;

[0032] Figure 6 This is a cross-sectional view of the structure of the mold core in the embodiment of the present utility model;

[0033] Figure 7 This is a schematic diagram of the structure of the support pad in the embodiment of the utility model; Figure 7 a is a cross-sectional view of the structural relationship of the support pad, Figure 7 b is a side view of the structural relationship of the support pad;

[0034] Figure 8 This is a schematic diagram of the structure of the guide cylinder in the embodiment of the utility model; Figure 8 a is the structural relationship sectional view of the guide cylinder, Figure 8 b is a side view of the structural relationship of the guide cylinder.

[0035] In the figure: 1. Barrel; 2. Thrust rod; 3. Force transmission block; 4. Base; 5. Stopper; 6. Split cone die; 7. Support pad; 8. Guide cylinder; 9. Flat die; 10. Die base; 11. Die support; 12. Integral cone die; 13. Shell; 14. Blank; 15. Titanium alloy bar; 16. Die body; 17. Die core; 18. First lifting hole; 19. Positioning slot; 20. Second lifting hole; 21. Positioning block;

[0036] 101. First inlet conical surface; 102. Second conical surface; 103. Step surface;

[0037] 201. Second inlet conical surface; 202. Sizing zone; 203. Outlet counter-conical surface; 204. First conical surface; 205. Cylindrical surface. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and understand the present invention and are not intended to limit the present invention.

[0039] This embodiment discloses an extrusion die for titanium alloy bars, such as Figure 3 and Figure 4 As shown, the extrusion die comprises a barrel 1, a thrust rod 2 with its force-applying end extending from the right side into the barrel 1, a force-transmitting block 3 disposed within the barrel 1 and positioned between the billet 14 and the force-applying end of the thrust rod 2, a base 4 and a stopper 5 assembled on the left side of the barrel 1, a split cone die 6 assembled within the inner cavity formed by the base 4 and the stopper 5, and a guide assembly connected to the left side of the base 4 and the stopper 5. During operation, the titanium alloy billet 14 is loaded into the barrel 1, and the thrust rod 2 applies a thrust to the titanium alloy billet 14 via the force-transmitting block 3. Under this thrust, the titanium alloy billet 14 passes through the core 17 of the split cone die 6 and becomes a titanium alloy bar 15.

[0040] It should be noted that the directional terms such as left and right defined in this embodiment are based on the symbols in the accompanying drawings, which are only for the convenience of describing this embodiment and are not used to limit this embodiment.

[0041] The barrel 1, thrust rod 2, and force transmission block 3 in this embodiment are all conventional. The base 4 and stopper 5 are only adaptively designed in terms of their contour structure based on the split-cone die 6. Specifically, after the base 4 and stopper 5 are assembled on the left side of the barrel 1, they cooperate with the left end of the barrel 1 to form an inner cavity. The inner contour of this inner cavity is adapted to the outer contour of the split-cone die 6, allowing the split-cone die 6 to fit within this inner cavity and thus be secured to the left side of the barrel 1.

[0042] like Figure 5 As shown, the working area entrance of the split cone mold 6 is a cone surface, and as shown in FIG. Figure 3 As shown, after being assembled on the left side of the barrel 1, the edge of the working area entrance of the split cone die 6 fits the inner wall of the barrel 1, so that the deformation "dead zone" formed at the entrance of the working area is very small, the metal flow is smoother during hot extrusion, and the copper sleeve wrapped around the blank 14 will not be scratched, which can play a good lubricating role, thereby ensuring product quality.

[0043] Specifically, the split cone mold 6 in this embodiment is an annular structure, comprising an integral mold body 16 and a mold core 17. In this embodiment, the mold body 16 and the mold core 17 are both made of hot-working die steel 4Cr5MoSiV1, with a Rockwell hardness of HRC45 to HRC55 after quenching and tempering.

[0044] like Figure 5 and Figure 6 As shown, the inner profile of the mold core 17 includes a second inlet conical surface 201, a sizing zone 202, and an outlet counter-conical surface 203. The cone angle α1 of the second inlet conical surface 201 is 100-120°, the length of the sizing zone 202 is 10-20 mm, and the cone angle α2 of the outlet counter-conical surface 203 is 10-14°. The second inlet conical surface 201 and the sizing zone 202 are connected by a rounded corner, which makes the transition smoother. In this embodiment, the fillet radius r is 10 mm. In this embodiment, the sizing zone 202 of the mold core 17 is cylindrical and serves as the primary working area for forming the titanium alloy bar 15. The inner diameter of the sizing zone 202 is 1.014 times the outer diameter of the bar. The outer contour of mold core 17 includes a first conical surface 204 and a cylindrical surface 205. The first conical surface 204 has a taper angle β of 20 to 26 degrees and a length l1 of 20 to 30 mm. The cylindrical surface 205 has a length l2 of 15 to 28 mm. In this embodiment, the maximum thickness h of mold core 17 is 35 to 50 mm, and the surface roughness of mold core 17 is no greater than 0.8 μm.

[0045] In this embodiment, the cone angle α1 of the second inlet conical surface 201 of the inner contour of the mold core 17 is 110°, the length of the sizing zone 202 is 18 mm, and the cone angle α2 of the outlet counter-conical surface 203 is 12°; the cone angle β of the first conical surface 204 of the outer contour of the mold core 17 is 23°, and the length l1 is 30 mm; the length l2 of the cylindrical surface 205 is 25 mm; and the maximum thickness h of the mold core 17 is 50 mm.

[0046] like Figure 5 As shown, the mold body 16 has an assembly cavity and a first inlet conical surface 101 that connects to the inlet of the assembly cavity. The assembly cavity contour matches the outer contour of the mold core 17, allowing the mold core 17 to be assembled into the mold body 16 through the assembly cavity. The taper angle γ1 of the first inlet conical surface 101 is 100-120°. The outer contour of the mold body 16 includes a second conical surface 102 on the right section and a stepped surface 103 on the left section. The taper angle γ2 of the second conical surface 102 is 60° (i.e., the assembly angle at which the mold body 16 is fixed to the barrel 1 is 60°).

[0047] In this embodiment, the cone angle γ1 of the first inlet conical surface 101 of the mold body 16 is equal to the cone angle α1 of the second inlet conical surface 201 of the mold core 17, and after the mold body 16 and the mold core 17 are assembled into one, the center lines of the two are coaxial, so that the working area entrance of the split cone mold 6 formed by the mold body 16 and the mold core 17 is a smoothly transitioned cone surface.

[0048] In this embodiment, the cone angle γ1 of the first inlet conical surface 101 of the mold body 16 is 110°.

[0049] If additional explanation is needed, such as Figure 3 and Figure 4 As shown, the inner contour of the base 4 is also a stepped surface, designed to correspond to the stepped surface 103 of the mold body 16 of the split cone mold 6, forming a concave-convex assembly relationship between the two. A conical surface is provided at the left discharge end of the barrel 1, designed to correspond to the second conical surface 102 of the mold body 16 of the split cone mold 6. The fixed assembly angle between the two is the taper angle γ2 of the second conical surface 102. The baffle is a hollow cylinder with an outer diameter equal to the maximum outer contour of the mold body 16 of the split cone mold 6 and an inner diameter 10-15 mm larger than the port size of the outlet counter-conical surface 203 of the mold core 17 of the split cone mold 6. In this embodiment, the inner diameter of the baffle is 10 mm larger than the port size of the outlet counter-conical surface 203 of the mold core 17 of the split cone mold 6. In actual use, a support system is provided on the outside of the baffle to withstand thrust.

[0050] In this embodiment, a first hoisting hole 18 is further provided on the top of the base 4 for hoisting.

[0051] The guide assembly is used to guide the extruded bar to improve its straightness. Figure 3 As shown, the guide assembly includes a support pad 7 and a guide cylinder 8.

[0052] The support pad 7 is a cylindrical structure assembled on the left side of the base 4. Figure 7 As shown, four positioning grooves 19 are evenly distributed along the inner hole edge on the right end surface of the support pad 7 in the circumferential direction. The positioning grooves 19 are rectangular. The top of the support pad 7 is provided with a second lifting hole 20 for lifting. Figure 8 As shown, the guide cylinder 8 is a cylindrical structure that is inserted into the inner hole of the support pad 7. Four positioning blocks 21 are evenly distributed along the circumference of the outer edge of the right end surface of the guide cylinder 8. The positioning blocks 21 are rectangular and match the shape of the positioning grooves 19. In this embodiment, the four positioning grooves 19 of the support pad 7 are evenly distributed at 90° intervals (as shown in FIG. Figure 7 As shown in b), the four positioning blocks 21 of the guide cylinder 8 are evenly distributed at 90° intervals (as shown in Figure 8 As shown in FIG. 2 , when the guide cylinder 8 is inserted into the inner hole of the support pad 7 , the positioning block 21 is located in the corresponding positioning groove 19 .

[0053] Furthermore, the length of the guide cylinder 8 is greater than the length of the support pad 7 , and the diameter of the inner hole of the guide cylinder 8 is equal to the inner diameter of the stopper 5 .

[0054] The forming process of producing the titanium alloy bar 15 using this embodiment is as follows: after installing the base 4, the block 5, the split cone die 6, the barrel 1, the support pad 7 and the guide cylinder 8 on the hot extruder, the graphite lubricant is evenly applied to the barrel 1 and the split cone die 6; the copper-sheathed titanium alloy billet 14 is heated to 840°C~1000°C in an electric furnace, loaded into the barrel 1, and then the pushing system is used to push the thrust rod 2 and the force transmission block 3 to move in the extrusion direction. The force transmission block 3 pushes the titanium alloy billet 14, and the titanium alloy billet 14 passes through the core 17 cavity of the split cone die 6 to become a titanium alloy bar 15.

[0055] It should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art may still modify the technical solutions described in the above embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An extrusion die for titanium alloy bars, characterized by: It includes a barrel, a thrust rod with a force-applying end extending into the barrel from the right side, a force-transmitting block provided in the barrel and located between the blank and the force-applying end of the thrust rod, a base and a stopper assembled on the left side of the barrel, and a split cone die assembled in an inner cavity structure formed by the base and the stopper; Also included is a guide assembly connected to the base and the left side of the stopper for guiding the extruded bar material to improve straightness; The working area inlet of the split cone mold is a cone surface, and the edge of the working area inlet fits the inner wall of the barrel.

2. The extrusion die for titanium alloy bars according to claim 1, characterized in that: The split cone mold is an annular structure, comprising a mold body and a mold core assembled into one body; the mold body has an assembly cavity adapted to the outer contour of the mold core and a first inlet conical surface connected to the assembly cavity; the inner contour of the mold core includes a second inlet conical surface, a sizing area and an outlet counter-conical surface; The cone angle γ1 of the first inlet cone surface is equal to the cone angle α1 of the second inlet cone surface, and the center lines of the mold body and the mold core are coaxial, so that the working area inlet of the split cone mold formed by the mold body and the mold core is a cone surface.

3. The extrusion die for titanium alloy bars according to claim 2, characterized in that: In the mold core, the cone angle α1 of the second inlet cone surface is 100-120 degrees, the length of the sizing zone is 10-20 mm, and the cone angle α2 of the outlet counter-cone surface is 10-14 degrees.

4. The extrusion die for titanium alloy bars according to claim 3, characterized in that: The sizing area of ​​the mold core is cylindrical, and the inner diameter of the sizing area is 1.014 times the outer diameter of the bar.

5. The titanium alloy bar extrusion die according to claim 4, characterized in that: The second inlet conical surface of the mold core is connected to the sizing area with a fillet, and the fillet radius is 10 mm.

6. The titanium alloy bar extrusion die according to any one of claims 2 to 5, characterized in that: The outer contour of the mold core includes a first conical surface and a cylindrical surface; the cone angle β of the first conical surface is 20-26°, and the length l1 is 20-30 mm; the length l2 of the cylindrical surface is 15-28 mm.

7. The extrusion die for titanium alloy bar according to claim 6, characterized in that: The outer contour of the right section of the mold body is a second conical surface, and the outer contour of the left section is a step surface; the cone angle γ2 of the second conical surface is 60°.

8. The titanium alloy bar extrusion die according to any one of claims 1 to 5 and 7, characterized in that: The guide assembly includes a support pad and a guide cylinder; wherein the support pad is a cylindrical structure assembled on the left side of the base, and a plurality of positioning grooves are evenly distributed along the edge of the inner hole on the right end surface of the support pad; the guide cylinder is a cylindrical structure inserted into the inner hole of the support pad, and a plurality of positioning blocks are provided on the edge of the right end surface of the guide cylinder to adapt to the positioning grooves; The length of the guide cylinder is greater than the length of the support pad, and the diameter of the inner hole of the guide cylinder is equal to the inner diameter of the stop block.

9. The titanium alloy bar extrusion die according to claim 8, characterized in that: The stopper is a hollow cylinder, the outer diameter of which is equal to the maximum outer contour of the split cone die, and the inner diameter of which is 10 to 15 mm larger than the outlet end of the split cone die.

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