CN111940525A - A rotary extrusion device for preparing ultra-fine crystal tubes - Google Patents

Abstract

The invention discloses a rotary extrusion device for preparing ultra-fine crystal tubes, comprising: an extrusion punch, including a bearing installation block, a spiral groove column, an extrusion block and a positioning mandrel, and an extrusion support is arranged on the bearing installation block The plate is connected by a horizontal bearing, and the outer surface of the spiral groove column is provided with a helical semicircular groove; the extrusion die is provided with an extrusion through hole corresponding to the position of the pipe; the screw nut is arranged on the extrusion die, The spiral groove column passes through the screw nut to press the pipe into the extrusion through hole. The inner surface of the screw nut is provided with a helical semicircular groove, which is consistent with the helix angle of the spiral groove column. The inner and outer grooves form a circular channel , The ball circulation channel is formed by setting the ball and the ball return tube, and the extrusion punch generates a twisting force under the action of the spiral ball, so that the extrusion punch drives the pipe to twist and extrude in the extrusion through hole. The device can realize the composite deformation of the positive extrusion and torsion of the pipe material by axial loading, and can obtain the high-performance pipe material with ultra-fine grain structure in one extrusion.

Description

A rotary extrusion device for preparing ultra-fine crystal tubes

technical field

The invention relates to the technical field of metal material extrusion, in particular to a rotary extrusion device for preparing ultra-fine crystal tubes.

Background technique

Pipes are widely used in aviation, automobile, petrochemical, construction and other industries. With the lightweight of engineering components and the society's higher and higher requirements for energy conservation and environmental protection, the application of high-performance pipes has received more and more attention. As we all know, grain refinement is one of the most effective means to improve the comprehensive properties of materials. Severe plastic deformation is the most promising method to realize the ultra-refinement of material structure. At present, common severe plastic deformation techniques include equal diameter angular extrusion (ECAP), high pressure torsion (HPT), and reciprocating extrusion (CEC). At present, sub-micron or even nano-scale structures have been prepared in rods, sheets and tubes through severe plastic deformation, which improves material properties.

The techniques used to prepare ultra-fine crystalline tubes include tube channel extrusion (TCP), tube channel corner extrusion (TCAP), tube parallel channel corner extrusion (PTCAP), tube reciprocating extrusion (TCEC), etc. When the structure of the pipe is modified, there are defects in the limited length of the pipe, the need for repeated deformation and multiple passes, resulting in low deformation efficiency and high requirements for molds, and it is difficult to achieve industrial application. Torsional deformation generates a large amount of shear strain inside the material, which is conducive to the movement of dislocations in the material. The material structure can be rapidly refined through dislocation interaction or mechanical crushing, and it has received more and more attention. It is applied to the refinement of pipe structure. , proposed the tube high pressure torsion (HPTT) technology, which can realize the relative shearing between the inner and outer walls of the tube, and has a good grain refinement effect. Rotation, etc. The friction stir back extrusion (FSBE), shear assisted extrusion (ShAPE), rotary extrusion (RE) and other technologies proposed based on the friction stir idea can make the material produce Rotation can realize the composite deformation of torsion and extrusion, which can not only reduce the forming load, but also obtain a better grain refinement effect, but in these technologies, one of the components needs to be rotated, and the equipment needs to have a rotating function or a separate set is provided. The power source is used for component rotation, and special equipment needs to be developed separately, which is costly and expensive. The common pipe extrusion equipment often does not have the function of rotation.

SUMMARY OF THE INVENTION

Purpose of the invention: In order to overcome the deficiencies of the background technology, the present invention discloses a rotary extrusion device for preparing ultra-fine crystal tubes, which realizes the extrusion and torsional deformation of the tubes at the same time under unidirectional loading without rotational drive.

Technical solution: The rotary extrusion device for preparing ultra-fine crystal tube materials according to the present invention includes:

An extrusion punch, the extrusion punch includes a bearing mounting block, a spiral groove column, an extrusion block and a positioning mandrel that are spliced in sequence, the bearing mounting block is provided with an extrusion support plate, and the extrusion support plate It is connected with the bearing mounting block through a horizontal bearing, the outer surface of the spiral groove column is provided with a helical semicircular groove, and the pipe is sleeved on the positioning mandrel and moves with the extrusion punch;

an extrusion die, wherein an extrusion through hole is opened at the position of the extrusion die corresponding to the pipe;

Screw nut, the screw nut is arranged on the extrusion die, the spiral groove column of the extrusion punch passes through the screw nut to press the pipe into the extrusion through hole, and the inner surface of the screw nut is opened A helical semi-circular groove whose helix angle is consistent with the groove on the outer surface of the spiral groove column. After the spiral groove column is inserted into the screw nut, the inner and outer grooves form a circular channel, and the circular channel is provided with balls. There is a ball return tube on the screw nut, which is respectively connected with the upper and lower ends of the groove on the inner surface of the screw nut to form a ball circulation channel, which applies pressure to the extrusion support plate, and the extrusion punch generates a torsion force under the action of the spiral ball, so that the The extrusion punch drives the pipe material to perform torsional extrusion in the extrusion through hole.

When in use, insert the pipe to be extruded on the positioning mandrel, align the extrusion through hole, the hydraulic press or the power source of the extruder loads the upper end of the extrusion support plate, the extrusion punch moves downward from this, and the spiral groove column Under the action of the ball channel, the torsional force is generated, and at the same time, under the action of the horizontal bearing, the extrusion punch and the extrusion support plate rotate relative to the central vertical axis, thereby realizing the rotation of the pipe while extruding.

Further, the helix angle of the helical semicircular groove ranges from 30° to 70°.

Further, the extrusion through hole is a stepped through hole, including a pipe material placement area, an extrusion area and a sizing belt area that are spliced in sequence, and the pipe material passes through the pipe material placing area, the extrusion area and the sizing belt area in sequence.

Further, the outer diameter of the extrusion block is smaller than the diameter of the spiral groove column and the pipe placement area of the extrusion through hole.

Further, the surface of the extrusion zone is roughened to improve the rotary extrusion effect.

Further, a guide post is provided at the bottom of the lead screw nut, the guide post is fixed on the lead screw nut by interference fit, and a guide hole is provided at the position of the extrusion die corresponding to the guide post.

Further, the positioning mandrel is covered with a squeeze pad, the squeeze pad and the squeeze block are positioned through the concave-convex structure of the contact surface, and the contact surface between the squeeze pad and the pipe is a wave structure, which can improve the billet. Twist effect.

Beneficial effects: Compared with the prior art, the advantages of the present invention are: firstly, the device of the present invention can simultaneously realize the axial feeding motion and the rotational motion around the axial direction under the condition of unidirectional loading of a single power source, relative to the feeding motion. The device for separate control of motion and rotation has the advantages of simple structure, low cost, and convenient operation; secondly, the combination of positive extrusion and torsional deformation of the pipe, the degree of deformation in a single pass is large, and the loading mode acting on the pipe is more Diverse, the stress state of the material is more complex, which is conducive to accelerating the tissue refinement of the material; furthermore, by adjusting the helix angle of the helical groove, the diameter of the helical groove column and the extrusion ratio of the pipe, different degrees can be obtained. The combination of extrusion and torsional deformation can realize the regulation of material structure and properties.

Description of drawings

Fig. 1 is the assembly drawing before extrusion of the present invention;

Fig. 2 is the structural schematic diagram of extrusion punch of the present invention;

Fig. 3 is the structure schematic diagram of the screw nut of the present invention;

Fig. 4 is the structure schematic diagram of the squeeze pad of the present invention;

FIG. 5 is an assembly view of the present invention in a squeezed state.

Detailed ways

The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments.

As shown in Figure 1, the rotary extrusion device for preparing ultra-fine crystal tubes includes:

As shown in FIG. 2 , the extrusion punch 1 includes a bearing mounting block 101 , a spiral groove column 102 , an extrusion block 103 and a positioning mandrel 104 spliced in sequence. An extrusion support plate 2 is provided, and a bearing installation groove is provided on the opposite surface of the extrusion support plate 2 and the bearing installation block 101, and is connected by the horizontal bearing 201. The extrusion punch 1 can perform horizontal angle under the action of the horizontal bearing 201. turn. The outer surface of the helical groove column 102 is provided with a helical semicircular groove, the helix angle is α, and the pipe is sleeved on the positioning mandrel 104. When the extrusion punch 1 moves downward, the extrusion block 103 is opposite to the positioning core. The tubing on rod 104 is extruded.

The extrusion die 3 cooperates with the extrusion punch 1. The extrusion die 3 has an extrusion through hole 301 at the position corresponding to the pipe, and the extrusion through hole 301 is a stepped through hole. The hole includes the pipe placement area 311, the extrusion area 321 and the sizing belt area 331 that are spliced in sequence. The inner diameter of the pipe placement area 311 transitions to the sizing belt area 331 through the inclined extrusion area 321, and the pipe to be pressed is subjected to the extrusion block 103. The extrusion is performed through the pipe placement area 311, the extrusion area 321 and the sizing belt area 331 in sequence, and the surface of the extrusion area 321 is roughened to improve the effect of rotary extrusion.

As shown in FIG. 3 , the screw nut 4 is arranged on the extrusion die 3 , and the inner diameter of the screw nut 4 is slightly larger than the spiral groove column 102 of the extrusion die 3 . The slot column 102 can pass through the screw nut 4 to press the pipe into the extrusion through hole 301 . The groove and the spiral groove on the inner surface of the screw nut 4 have the same helix angle, that is, α=β, and the value range is preferably 30° to 70°. After the spiral groove column 102 is inserted into the screw nut 4, the inner and outer grooves A circular channel is formed, a ball 401 is arranged in the circular channel, and a ball return tube 402 is arranged on the screw nut 4, which is respectively connected with the upper and lower ends of the groove on the inner surface of the screw nut 4 to form a ball circulation channel. The pressing support plate 2 exerts pressure, and the extrusion punch 1 generates a twisting force under the action of the spiral ball, so that the extrusion punch 1 drives the pipe to perform twist extrusion in the extrusion through hole 301 . By adjusting the helix angle of the helical groove, the diameter of the helical groove column and the extrusion ratio of the pipe, various combinations of extrusion and torsional deformation can be obtained, thereby realizing the regulation of the material structure and properties.

In order to ensure the normal operation of the whole device, the outer diameter of the extrusion block 103 is smaller than the diameter of the spiral groove column 102 and the diameter of the pipe placement area 311 of the extrusion through hole 301 .

The lead screw nut 4 is arranged on the extrusion die 3, and two guide posts 401 are arranged at the bottom of the lead screw nut 4. The guide posts 403 are fixed on the lead screw nut 4 through interference fit. The female die 3 is provided with a guide hole 302 at a position corresponding to the guide post 403 , and the lead screw nut 4 is fixed by inserting the guide post 403 into the guide hole 302 , and can move up and down.

In order to make the position of the pipe more stable during rotary extrusion, the positioning mandrel 104 is covered with a pressing pad 105 as shown in FIG. 4 , and the pressing pad 105 and the pressing block 103 pass through the concave-convex structure of the contact surface. To achieve positioning, the concave-convex structure can be a fan-shaped groove and a fan-shaped boss structure that cooperate with the two, and the contact surface of the squeeze pad 105 and the pipe is a wave structure, which can improve the twisting effect of the pipe; the squeeze pad 105 is in the positioning The mandrel 104 is movably arranged so that the formed pipe can be easily removed.

When using the rotary extrusion device for preparing the ultrafine crystal tube material of the present invention to extrude the pipe material, follow the following steps:

S1. Put the extrusion punch 1 into the screw nut 4, the helical groove column 102 of the extrusion punch 1 and the helical groove of the inner hole of the screw nut form a circular channel, and the ball 401 is loaded into the circular channel from the upper end The ball-returning tube 402 is installed in the shaped channel, and the ball-returning tube 402 is matched to form a ball circulation channel, and the guide post 403 is fixed on the lower end of the screw nut 4;

S2. Fix the extrusion die 3 on the hydraulic press or extruder, put the pipe into the pipe placement area 311, put the extrusion pad 105 on the front end of the extrusion punch 1 to locate the mandrel 104, and insert the guide post 403 into the extrusion In the guide hole 302 corresponding to the pressing die 3, the positioning mandrel 104 of the pressing die 1 is inserted into the central hole of the pipe;

S3, install the plane bearing 201 in the bearing installation groove of the extrusion punch 1 and the extrusion support plate 2;

S4. The hydraulic press or the power source of the extruder loads the upper end of the extrusion support plate 2, and the extrusion punch 1 moves downward under the guidance of the ball 401, as shown in FIG. Shear deformation occurs between the inner and outer walls, and the material structure is refined; by heating the pipe and the parts in contact with the pipe, warm extrusion or hot extrusion can be realized;

S5 , lift the screw nut 4 upward, pull out the extrusion punch 1 from the pipe, and take out the extrusion pad 105 .

Repeat S2-S5.

Claims (7)

1. A rotary extrusion device for preparing an ultra-fine grained pipe is characterized by comprising:

the extrusion male die (1) comprises a bearing mounting block (101), a spiral groove column (102), an extrusion block (103) and a positioning core rod (104) which are sequentially spliced, wherein an extrusion supporting plate (2) is arranged on the bearing mounting block (101), the extrusion supporting plate (2) is connected with the bearing mounting block (101) through a horizontal bearing (201), a spiral semicircular groove is formed in the outer surface of the spiral groove column (102), and a pipe is sleeved on the positioning core rod (104) and moves along with the extrusion male die (1);

the pipe fitting extruding die comprises an extruding female die (3), wherein an extruding through hole (301) is formed in the position, corresponding to the pipe, of the extruding female die (3);

the screw rod nut (4), the screw rod nut (4) is arranged on the extrusion concave die (3), the spiral groove column (102) of the extrusion convex die (1) penetrates through the feed screw nut (4) to press the pipe in the extrusion through hole (301), a spiral semicircular groove with a lead angle consistent with that of the groove on the outer surface of the spiral groove column (102) is formed in the inner surface of the screw rod nut (4), after the spiral groove column (102) is inserted into the screw rod nut (4), the inner groove and the outer groove form a circular channel, a ball (401) is arranged in the circular channel, the screw nut (4) is provided with a ball returning pipe (402) which is communicated with the upper end and the lower end of the groove on the inner surface of the screw nut (4) to form a ball circulation channel, pressure is applied to the extrusion support plate (2), the extrusion male die (1) generates torsional force under the action of spiral balls, and the extrusion male die (1) drives the pipe to be twisted and extruded in the extrusion through hole (301).

2. The rotary extrusion apparatus for manufacturing ultra-fine grained pipe according to claim 1, wherein: the spiral angle of the spiral semicircular groove ranges from 30 degrees to 70 degrees.

3. The rotary extrusion apparatus for manufacturing ultra-fine grained pipe according to claim 1, wherein: the extrusion through hole (301) is a step-shaped through hole and comprises a pipe placing area (311), an extrusion area (321) and a sizing belt area (331) which are sequentially spliced.

4. The rotary extrusion apparatus for manufacturing ultra-fine grained pipe according to claim 3, wherein: the outer diameter of the extrusion block (103) is smaller than the diameters of the spiral groove column (102) and the pipe placing area (311) of the extrusion through hole (301).

5. The rotary extrusion apparatus for manufacturing ultra-fine grained pipe according to claim 3, wherein: the surface of the extrusion area (321) is roughened, so that the rotary extrusion effect is improved.

6. The rotary extrusion apparatus for manufacturing ultra-fine grained pipe according to claim 1, wherein: the bottom of the screw rod nut (4) is provided with a guide post (403), and the position of the extrusion female die (3) corresponding to the guide post (403) is provided with a guide hole (302).

7. The rotary extrusion apparatus for manufacturing ultra-fine grained pipe according to claim 1, wherein: the positioning core rod (104) is sleeved with an extrusion pad (105), the extrusion pad (105) and the extrusion block (103) are positioned through a concave-convex structure of a contact surface, and the contact surface of the extrusion pad (105) and the pipe is of a wave structure.

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