Split cone die and titanium alloy pipe forming die applying same

Abstract

The utility model discloses a split cone die and a titanium alloy pipe forming die applying the split cone die, the split cone die is of an annular structure, and comprises a die base and a die insert which are assembled into a whole; the mold base is provided with an inner cavity matched with the outer contour of the mold insert and a first inlet conical surface connected with the inner cavity. The inner contour of the mold insert comprises a second inlet conical surface, a sizing area and an outlet reverse conical surface. And the taper angle gamma 1 of the first inlet conical surface is equal to the taper angle alpha 1 of the second inlet conical surface, so that the whole working area inlet formed by the die base and the die insert is a conical surface. The titanium alloy pipe forming die comprises a charging barrel, a pushing system, a force transmission block, an inner die, a shell, a baffle and the split cone die. According to the utility model, the defect that a plane die and a flat cone die are easy to scratch a copper sleeve is overcome, the defects of large unit weight, inflexible replacement and high die replacement cost of an integral cone die are overcome, and when the die is used in a hot extrusion process, a produced product is high in dimensional accuracy and good in appearance quality.

Description

Technical Field

[0001] The utility model belongs to the technical field of nonferrous metal processing, and relates to the forming of titanium alloy pipes, in particular to a split cone die and a titanium alloy pipe forming die using the split cone die. Background Art

[0002] Metal pipe forming processes include: bar boring, sheet coil welding, hot piercing, forging, and hot extrusion. Among them, bar boring has a low material utilization rate; sheet coil welding results in welds, resulting in inconsistent overall performance of the formed pipe; hot piercing has high heating temperatures, making microstructure difficult to control, resulting in poor stability and prone to defects; forging is slow and suffers from poor dimensional accuracy; while hot extrusion subjects the billet to a triaxial compressive stress state, enabling large deformation in a single pass, facilitating the deformation of low-plasticity materials and making it suitable for the hot working of titanium alloys. Therefore, hot extrusion has become the mainstream production process for blanking titanium alloy pipes.

[0003] The hot extrusion process includes billet preparation, hot expansion, copper sleeve wrapping and lubrication, and hot extrusion. The types of extrusion dies used in the hot extrusion process include the flat die 12, the flat cone die 13, and the integral cone die 16. However, the flat die 12, the flat cone die 13, and the integral cone die 16 all have certain problems when used, as follows:

[0004] First, the structure of the existing plane mold 12 is as follows Figure 1 As shown, it is combined with the barrel, thrust system, force transmission block, inner die and other components in cooperation with the die base 14 and the die support 15 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 pipe formed by the deformation of the blank.

[0005] Second, the structure of the existing flat cone die 13 is as follows Figure 2 As shown, it is combined with the barrel, thrust system, force transmission block, inner die and other components in cooperation with the die base 14 and the die support 15 to form an extrusion die. When used in the hot extrusion process, the inlet of the extrusion die working area is a cone surface, and the deformation "dead zone" is reduced. However, since there is still a platform on one side of the extrusion die inlet, the flow of the outer surface metal is blocked, and the copper sleeve wrapped around the surface of the blank is still easy to be torn;

[0006] Third, the structure of the existing integral cone mold 16 is as follows Figure 3As shown, it is combined with the outer shell 8, the barrel, thrust system, force transmission block, inner mold, and other components to form an extrusion die. When used in the hot extrusion process, the entire working area of ​​the extrusion die is a conical surface at the entrance, without a platform. This reduces the flow velocity difference between the inner and outer surfaces of the billet, minimizes the deformation "dead zone", and smoothes the flow of metal. The copper sleeve wrapped around the billet surface provides excellent lubrication. However, the integral conical die 16 is large in size, heavy in weight, difficult to machine, and inflexible to replace. The sizing area is the part with the highest damage rate. Once damaged, the entire die must be replaced, which is costly. Utility Model Content

[0007] The utility model provides a split cone die and a titanium alloy pipe forming die using the same, aiming to solve the shortcomings of flat dies and flat cone dies that easily scratch the copper sleeve, and overcome the shortcomings of the integral cone die being heavy, inflexible to replace, and high die replacement cost, thereby ensuring a smooth extrusion process and guaranteeing product quality.

[0008] To achieve the above-mentioned object, the technical solution adopted by the present invention is as follows: a split cone mold, which is an annular structure and includes a mold base and a mold insert assembled into one body; the mold base has an inner cavity adapted to the outer contour of the mold insert and a first inlet conical surface connected to the inner cavity; the inner contour of the mold insert includes a second inlet conical surface, a sizing area, and an outlet counter-conical surface;

[0009] The cone angle γ1 of the first inlet conical surface is equal to the cone angle α1 of the second inlet conical surface, so that the entire working area inlet formed by the mold base and the mold insert is a cone surface.

[0010] As a limitation of the present invention, in the die insert, the cone angle α1 of the second inlet conical surface is 100-120°, the length of the sizing zone is 8-16 mm, and the cone angle α2 of the outlet counter-conical surface is 8-10°.

[0011] As a further limitation of the present invention, in the die insert, the second inlet conical surface is connected to the sizing zone with a fillet, and the fillet radius r is 12.5 mm.

[0012] As another limitation of the present invention, the outer contour of the mold insert includes a first conical surface and a cylindrical surface; wherein the cone angle β of the first conical surface is 24-26°, and the length l1 is 11-30 mm; the length l2 of the cylindrical surface is 25-30 mm.

[0013] As a further limitation of the present invention, the mold insert is coaxial with a centerline of the mold base.

[0014] As a further limitation of the present invention, the front section outer contour of the mold base is a second conical surface, and the rear section outer contour is a step surface; wherein the cone angle γ2 of the second conical surface is 60°.

[0015] The utility model also discloses a titanium alloy pipe forming die, comprising a barrel, a pushing system with a force-applying end extending into the barrel, a force-transmitting block arranged in the barrel and located between the blank and the force-applying end of the pushing system, an inner die passing through the pushing system and the force-transmitting block, and an outer shell and a baffle assembled at the discharge end of the barrel, and also comprising a split cone die;

[0016] The outer shell cooperates with the baffle to form an assembly cavity at the discharge end of the barrel for assembling the split cone mold;

[0017] The inlet edge of the mold base of the split cone mold is in contact with the inner wall of the barrel.

[0018] As a limitation of the present invention, the baffle is a hollow cylinder with an outer diameter equal to the maximum outer contour size of the split cone mold middle mold base and an inner diameter 6 to 20 mm larger than the port size of the outlet counter-cone surface of the split cone mold middle mold insert.

[0019] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0020] The present invention designs a new extrusion die for use in hot extrusion processes. This solves the drawback of using flat dies and flat cone dies, which suffer from the tendency of the copper sleeve enveloping the blank to be easily scraped off due to the deformation "dead zone" formed by the platform at the inlet. It also addresses the drawbacks of the monolithic cone die, which is heavy, bulky, inflexible to replace, and high die replacement costs. Specifically, the present invention employs a split cone die design (comprising a die insert and a die base). This split structure facilitates processing, and when the sizing zone is worn or damaged, only the die insert needs to be replaced, facilitating replacement and maintenance, saving expensive materials and reducing die replacement costs. Furthermore, the first inlet conical surface of the die base and the second inlet conical surface of the die insert adopt equal taper angles, resulting in the entire working area inlet formed by the die base and the die insert forming a single conical surface. When assembled into the barrel, the inlet edge of the conical surface abuts the barrel inner wall, ensuring a smooth transition between the inlet surfaces. This ensures smooth metal flow during hot extrusion, prevents the copper sleeve enveloping the blank from being scratched, and provides excellent lubrication, thereby ensuring product quality.

[0021] In summary, the structural design of the utility model is ingenious. When the utility model is used in the hot extrusion process, the products produced have high dimensional accuracy and good appearance quality. It is particularly suitable for promotion and application when using the hot extrusion process to produce titanium alloy pipes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0023] 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;

[0024] Figure 2 This is a cross-sectional view of the structural relationship of the flat cone mold assembly in the background technology of the present utility model;

[0025] Figure 3 A cross-sectional view of the structural relationship of the integral cone mold assembly in the background technology of the present utility model;

[0026] Figure 4 This is a cross-sectional view of the structural relationship of the split cone mold in the embodiment of the utility model;

[0027] Figure 5 This is a cross-sectional view of the structural relationship of the mold insert in the embodiment of the present utility model;

[0028] Figure 6 A cross-sectional view of the structural relationship of the split cone mold assembly in an embodiment of the present utility model;

[0029] Figure 7 This is a cross-sectional view of the structure of the titanium alloy pipe forming die in the embodiment of the present utility model;

[0030] Figure: 1. Die base; 2. Die insert; 3. Split cone die; 4. Barrel; 5. Pusher system; 6. Force transfer block; 7. Inner die; 8. Outer shell; 9. Baffle; 10. Blank; 11. Titanium alloy tube; 12. Flat die; 13. Flat cone die; 14. Die base; 15. Die support; 16. Integral cone die.

[0031] 101. First inlet conical surface; 102. Second conical surface; 103. Step surface;

[0032] 201. Second inlet conical surface; 202. Sizing zone; 203. Outlet counter-conical surface; 204. First conical surface; 205. Cylindrical surface. DETAILED DESCRIPTION

[0033] 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.

[0034] This embodiment discloses a split cone mold, such as Figure 4 As shown, the split cone mold 3 has an annular overall structure, comprising an integrally assembled mold base 1 and mold insert 2. In this embodiment, both the mold base 1 and the mold insert 2 are constructed from 4Cr5MoSiV1 hot-working die steel, achieving a Rockwell hardness of HRC45-HRC55 after quenching and tempering. Alternatively, the mold insert 2 may be constructed from 4Cr5MoSiV1 hot-working die steel, while the mold base 1 may be constructed from a more economical alloy steel.

[0035] like Figure 4 and Figure 5As shown, the inner contour of the die insert 2 includes a second inlet conical surface 201, a sizing zone 202, and an outlet counter-conical surface 203. The second inlet conical surface 201 has a taper angle α1 of 100-120°, the sizing zone 202 is 8-16 mm long (the sizing zone 202 is cylindrical and serves as the primary working area for forming the titanium alloy tube 11), and the outlet counter-conical surface 203 has a taper angle α2 of 8-10°. The second inlet conical surface 201 and the sizing zone 202 are connected by a rounded corner for a smoother transition. In this embodiment, the fillet radius r is 12.5 mm. The outer contour of the die insert 2 includes a first conical surface 204 and a cylindrical surface 205. The first conical surface 204 has a taper angle β of 24-26° and a length l1 of 11-30 mm; the cylindrical surface 205 has a length l2 of 25-30 mm. In this embodiment, the maximum thickness h of the mold insert 2 is 30-50 mm, and the surface roughness of the mold insert 2 is not greater than 1.0 μm.

[0036] In this embodiment, the cone angle α1 of the second inlet conical surface 201 of the inner contour of the mold insert 2 is 120°, the length of the sizing zone 202 is 16 mm, and the cone angle α2 of the outlet counter-conical surface 203 is 10°; the cone angle β of the first conical surface 204 of the outer contour of the mold insert 2 is 26°, 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 insert 2 is 50 mm.

[0037] like Figure 4 As shown, the mold base 1 has an inner cavity and a first inlet conical surface 101 that connects to the inner cavity entrance. The inner cavity contour matches the outer contour of the mold insert 2, allowing the mold insert 2 to be assembled into the mold base 1 through the inner cavity. The taper angle γ1 of the first inlet conical surface 101 is 100-120°. The outer contour of the mold base 1 includes a second conical surface 102 at the front and a stepped surface 103 at the rear. The taper angle γ2 of the second conical surface 102 is 60° (i.e., the assembly angle between the mold base 1 and the barrel 4 described below, when connected and fixed, is 60°).

[0038] In this embodiment, the cone angle γ1 of the first inlet conical surface 101 of the mold base 1 is equal to the cone angle α1 of the second inlet conical surface 201 of the mold insert 2, and after the mold base 1 and the mold insert 2 are assembled into one, the center lines of the two are coaxial, so that the entire working area inlet formed by the mold base 1 and the mold insert 2 is a smoothly transitioned cone surface.

[0039] In this embodiment, the cone angle γ1 of the first inlet conical surface 101 of the mold base 1 is 120°.

[0040] This embodiment also discloses a titanium alloy pipe forming die, which uses the split cone die 3 as described above. Figure 6 and Figure 7As shown, the titanium alloy tube forming die also includes a barrel 4, a pushing system 5 whose force-applying end extends into the barrel 4, a force transmission block 6 arranged in the barrel 4 and located between the blank 10 and the force-applying end of the pushing system 5, an inner mold 7 passing through the pushing system 5 and the force transmission block 6, and an outer shell 8 and a baffle 9 assembled at the discharge end of the barrel 4.

[0041] The barrel 4, thrust system, force transmission block 6 and inner mold 7 are all existing technologies, and the outer shell 8 and baffle 9 are adaptively designed in terms of contour structure based on the split cone mold 3. Specifically, after the outer shell 8 and baffle 9 are assembled at the discharge end of the barrel 4, the two cooperate to form an assembly cavity. The contour shape of the assembly cavity is compatible with the outer contour of the mold base 1 of the split cone mold 3, so that the split cone mold 3 can be assembled in the assembly cavity, and combined with the barrel 4, the pushing system 5, the force transmission block 6, the inner mold 7, the outer shell 8 and the baffle 9 to form a titanium alloy pipe forming mold. During operation, the titanium alloy blank 10 is loaded into the barrel 4, and the pushing system 5 applies thrust to the titanium alloy blank 10 through the force transmission block 6, so that the titanium alloy blank 10 passes through the cavity formed by the inner mold 7 and the split cone mold 3 to form a titanium alloy pipe 11.

[0042] If necessary, Figure 7 As shown, after the split cone die 3 is assembled in the above-mentioned assembly cavity, the inlet edge of the mold base 1 of the split cone die 3 fits the inner wall of the barrel 4, so that the inlet of the entire working area is a cone surface, the deformation "dead zone" is small, the metal flows smoothly during hot extrusion, and the copper sleeve wrapped around the blank 10 will not be scratched, which can play a good lubricating role, thereby ensuring product quality.

[0043] Further, such as Figure 6 As shown, the inner contour of the housing 8 is also a stepped surface, and is designed to correspond to the stepped surface 103 of the mold base 1 of the split cone mold 3, so that a concave-convex assembly relationship is formed between the two; Figure 7 As shown, the discharge end of the barrel 4 is provided with a tapered surface, designed to correspond to the second conical surface 102 of the mold base 1 of the split cone mold 3. The fixed connection angle between the two is 60°. The baffle 9 is a hollow cylinder with an outer diameter equal to the maximum outer contour of the mold base 1 of the split cone mold 3 and an inner diameter 6 to 20 mm larger than the port size of the outlet counter-conical surface 203 of the mold insert 2 of the split cone mold 3. In this embodiment, the inner diameter of the baffle 9 is 10 mm larger than the port size of the outlet counter-conical surface 203 of the mold insert 2 of the split cone mold 3. In actual use, a support system is provided on the outside of the baffle 9 to withstand thrust.

[0044] The forming process of producing the titanium alloy tube 11 using the tube forming mold disclosed in this embodiment is as follows: after installing the outer shell 8, baffle 9, split cone die 3, barrel 4 and inner die 7 on the hot extruder, heat it to 350°C and evenly apply graphite lubricant; heat the copper-sheathed titanium alloy billet 10 to 850°C~930°C, load it into the barrel 4, insert the inner die 7 into the inner cavity of the titanium alloy billet 10, and move it to the position of the split cone die 3; then the pushing system 5 pushes the force transmission block 6 to move in the extrusion direction, and the force transmission block 6 pushes the titanium alloy billet 10, and the titanium alloy billet 10 passes through the cavity formed by the inner die 7 and the split cone die 3 to become a titanium alloy tube 11.

[0045] 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. A split cone mold, characterized in that: The split cone mold is an annular structure, comprising a mold base and a mold insert assembled in one body; The mold base has an inner cavity adapted to the outer contour of the mold insert and a first inlet conical surface connected to the inner cavity. The inner contour of the mold insert includes a second inlet conical surface, a sizing area and an outlet counter-conical surface. The cone angle γ1 of the first inlet conical surface is equal to the cone angle α1 of the second inlet conical surface, so that the entire working area inlet formed by the mold base and the mold insert is a cone surface.

2. The split cone mold according to claim 1, characterized in that: In the die insert, the cone angle α1 of the second inlet cone surface is 100-120°, the length of the sizing zone is 8-16 mm, and the cone angle α2 of the outlet counter-cone surface is 8-10°.

3. The split cone mold according to claim 2, characterized in that: In the die insert, the second inlet conical surface is connected to the sizing zone with a fillet, and the fillet radius r is 12.5 mm.

4. The split cone mold according to any one of claims 1 to 3, characterized in that: The outer contour of the mold insert includes a first conical surface and a cylindrical surface; the cone angle β of the first conical surface is 24-26 degrees, and the length l1 is 11-30 mm; the length l2 of the cylindrical surface is 25-30 mm.

5. The split cone mold according to claim 4, characterized in that: The mold insert is coaxial with the center line of the mold base.

6. The split cone mold according to claim 5, characterized in that: The front section outer contour of the mold base is a second conical surface, and the rear section outer contour is a step surface; wherein the cone angle γ2 of the second conical surface is 60°.

7. A titanium alloy tube forming die, characterized by: The invention comprises a barrel, a pushing system with a force-applying end extending into the barrel, a force-transmitting block provided in the barrel and located between the blank and the force-applying end of the pushing system, an inner mold provided through the pushing system and the force-transmitting block, and a housing and a baffle assembled at the discharge end of the barrel, and also comprises the split cone mold according to claim 1; The outer shell cooperates with the baffle to form an assembly cavity at the discharge end of the barrel for assembling the split cone mold; The inlet edge of the mold base of the split cone mold is in contact with the inner wall of the barrel.

8. The titanium alloy tube forming die according to claim 7, characterized in that: The baffle is a hollow cylinder with an outer diameter equal to the maximum outer contour size of the split cone mold middle mold base and an inner diameter 6 to 20 mm larger than the port size of the outlet counter-cone surface of the split cone mold middle mold insert.

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