CN116060468A - Device and process method for preparing high-performance magnesium alloy pipe by asymmetric internal rotation extrusion - Google Patents

Device and process method for preparing high-performance magnesium alloy pipe by asymmetric internal rotation extrusion Download PDF

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Publication number
CN116060468A
CN116060468A CN202211570734.4A CN202211570734A CN116060468A CN 116060468 A CN116060468 A CN 116060468A CN 202211570734 A CN202211570734 A CN 202211570734A CN 116060468 A CN116060468 A CN 116060468A
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China
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magnesium alloy
central rod
alloy pipe
female die
extrusion
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CN202211570734.4A
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Chinese (zh)
Inventor
王利飞
杨朝阳
田磊
张强
王红霞
张长江
江树勇
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Taiyuan University of Technology
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Taiyuan University of Technology
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Priority to CN202211570734.4A priority Critical patent/CN116060468A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00—Extruding metal; Impact extrusion
    • B21C23/21—Presses specially adapted for extruding metal
    • B21C23/217—Tube extrusion presses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00—Extruding metal; Impact extrusion
    • B21C23/21—Presses specially adapted for extruding metal
    • B21C23/212—Details
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00—Extruding metal; Impact extrusion
    • B21C23/21—Presses specially adapted for extruding metal
    • B21C23/212—Details
    • B21C23/215—Devices for positioning or centering press components, e.g. die or container
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00—Extruding metal; Impact extrusion
    • B21C23/32—Lubrication of metal being extruded or of dies, or the like, e.g. physical state of lubricant, location where lubricant is applied
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C25/00—Profiling tools for metal extruding
    • B21C25/02—Dies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C29/00—Cooling or heating work or parts of the extrusion press; Gas treatment of work
    • B21C29/003—Cooling or heating of work
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Abstract

The invention belongs to the technical field of plastic forming of light metal, and particularly relates to a device and a process method for preparing a high-performance magnesium alloy pipe by asymmetric internal rotation extrusion. According to the invention, the rotating cam rotates in the pipe, so that the c-axis of the crystal grains of the pipe deflects along the linear speed direction of the rotating cam, the texture of the strong base surface is weakened, and the upper and lower linear speeds of the rotating cam are opposite, so that the deflection directions of the c-axis of the crystal grains of the pipe are opposite, the texture is greatly weakened, the anisotropism is reduced, and the comprehensive mechanical property of the magnesium alloy pipe is improved. The cavity of the female die has different upper and lower shapes, and the material passes through the cavity in the extrusion process at different upper and lower flow rates, so that up-and-down asymmetric shearing is formed, and the grain refinement effect is obvious. The rotary cam rotates and moves rightwards, so that the shearing extrusion space formed by the rotary cam and the cavity of the female die is changed at moment, the end face area is changed at moment with the height, the material up-down flow velocity is different, the up-down asymmetric shearing deformation is aggravated, and the grains are thinned.

Description

Device and process method for preparing high-performance magnesium alloy pipe by asymmetric internal rotation extrusion
Technical Field
The invention belongs to the technical field of plastic forming of light metal, and particularly relates to a device and a process method for preparing a high-performance magnesium alloy pipe by asymmetric internal rotation extrusion.
Background
Magnesium and its alloy are the lightest metallic structure materials at present, have density little, specific strength high, specific rigidity high, damping shock attenuation good, thermal conductivity good, electromagnetic shielding effect good, machining performance good, part size is stable, easy advantage such as recovery processing, therefore it holds the important place in fields such as car, 3C, aerospace, military, etc., is more praised as "green energy material of 21 st century".
However, the magnesium alloy has only 3 sliding systems at room temperature due to the close-packed hexagonal crystal structure, does not meet the polycrystal plastic deformation coordination principle of 5 sliding systems, macroscopically shows poor room temperature mechanical properties, and moreover, the basal plane and non-basal plane sliding of the magnesium alloy are difficult to start at low temperature deformation due to large critical shear stress difference of the basal plane and the non-basal plane sliding, so that the grains in the deformed material have preferred orientation to form strong basal plane textures, the subsequent deformation is not facilitated, and the application of the magnesium alloy in various fields is limited. Grain refinement can significantly improve various mechanical properties of the metal material, as can magnesium alloys. The severe plastic deformation technique has been demonstrated to be effective in refining magnesium alloy grains such as High Pressure Torsion (HPT), multi-directional forging (MDF), equal channel angular Extrusion (ECAP), rotary extrusion (TE), which can extremely refine grains and even obtain ultra-fine grain structure.
Therefore, the device and the method for effectively weakening the deformation texture and refining the crystal of the magnesium alloy are very important to expanding the application range of the magnesium alloy.
Disclosure of Invention
The invention aims to solve the problems and provides a device and a process method for preparing a high-performance magnesium alloy pipe by asymmetric internal rotation extrusion. By the device and the processing method thereof, continuous and severe asymmetric shearing deformation of the magnesium alloy blank occurs in the processing process, thereby realizing grain refinement, weakening texture, reducing anisotropy, improving the room temperature mechanical property of the magnesium alloy and expanding the application range of the magnesium alloy.
The device is realized by the following technical scheme: the device for preparing the high-performance magnesium alloy pipe by asymmetric internal rotation extrusion comprises an external die carrier, an asymmetric internal rotation shearing device and a power device, wherein:
the external die carrier comprises a left baffle, a right baffle, a plurality of bolts and heating cotton;
the asymmetric internal rotation shearing device comprises an annular male die, a female die, a central rod, a rotary cam, a rack and a positioning frame; the female die is horizontally provided with a left and right through cavity; the rotary cam is arranged in the inner space of the central rod, the axial direction of the rotary cam is horizontal and vertical to the axial direction of the central rod, the inner space is communicated with the outside up and down, the inner space protrudes outwards at two sides of the axial direction of the rotary cam to form a protruding part, the axial direction of the rotary cam protrudes outwards, and the protruding part is provided with a gear; the inner space of the central rod also comprises a pair of long grooves which are formed in the direction parallel to the axial direction of the central rod, the right ends of the pair of long grooves respectively penetrate through the two protruding parts, and the central rod is provided with a left space communicated with the left end of the long groove; an opening is arranged at the bottom of the annular male die;
the power device comprises a horizontal extruder, a pressure motor, an extrusion telescopic cavity and an extrusion telescopic pressure head which is connected with the extrusion telescopic cavity and is horizontally arranged;
the left baffle plate and the right baffle plate are arranged on the horizontal extruder, the female die is fixed between the left baffle plate and the right baffle plate, the left baffle plate and the right baffle plate are connected together through a plurality of bolts, heating cotton is coated around the female die, and through holes are formed in the positions, corresponding to the inner cavities of the female die, of the left baffle plate and the right baffle plate; the annular male die is fixed with the extrusion telescopic pressure head, is coaxially arranged with the female die and can extend into the female die from the left end; the center rod extends into the annular male die from the right end and is coaxially arranged with the female die; the rack is transversely arranged in the long groove of the inner space of the central rod and meshed with the gear of the protruding part of the rotary cam; the positioning frame extends into the left space of the center rod from the opening at the bottom of the annular male die to fix the rack; the space among the female die, the annular male die, the central rod and the rotary cam jointly forms a shearing extrusion space.
The extrusion space comprises a material placing area I, an asymmetric internal rotation shearing area II and a material discharging area III which are sequentially arranged from left to right, the material placing area I is used for placing an original magnesium alloy pipe, the asymmetric internal rotation shearing area II is used for carrying out up-down asymmetric shearing, meanwhile, the rotating cam rotates and moves rightward to enable the up-down shearing end face to change at any moment, and the material discharging area III is used for extruding the magnesium alloy pipe in the asymmetric internal rotation shearing area II. When the extrusion telescopic pressure head pushes the annular male die and the central rod to move rightwards, the rack is fixed by the locating frame, the extending part of the rotary cam in the central rod is meshed with the rack to start rotating, the rotation angular speed is omega, at the moment, the upper part and the lower part of materials in the female die start to asymmetrically shear under the upper and lower asymmetric shapes of the channel, and the upper and lower materials are different in relative flow velocity. The rotating cam rotates and moves rightward at the same time, the die is fixed, so that the shearing end faces formed by the upper and lower rotating cams and the inner wall of the die are changed at the moment, the upper and lower linear speeds of the rotating cam rotate in opposite directions, and the upper and lower grains are reversely deflected while the texture is weakened.
The device can realize that the high-performance magnesium alloy pipe is prepared by asymmetric internal rotation extrusion through the built-in rotating cam.
Further, the inner space of the center rod is used for containing the part of the rotary cam and is in an arc shape along the two sides of the axial direction of the center rod to form a circular track, and the inner cavity of the female die is connected with the inner wall corresponding to the rotary cam in a wave-shaped mechanism in which multiple sections of arcs with different radiuses are connected.
When the central rod moves rightwards along with the annular male die, the rack is fixed by the locating frame, and the rotary cam rotates anticlockwise under the engagement of the rack. When the central rod moves rightwards, the rotation angle of the rotary cam is smaller because the central rod has limited movement distance, the boundary of the rotary cam can not extend out of the central rod, and the asymmetric shearing deformation extrusion is mainly carried out by the difference of the radiuses of the upper arc and the lower arc of the cavity of the female die; when the central rod moves for a certain distance, the two sides of the boundary of the rotary cam extend out of the central rod upwards and downwards respectively when the rotary cam rotates to a certain angle, and at the moment, the asymmetric shear deformation is greatly aggravated by the fact that the boundary of the rotary cam extends out of the central rod except that the radii of the upper arc and the lower arc of the cavity of the female die are different. The shape of the end face of the deformation space is formed by the cavity of the female die and the rotating cam, and the rotating angle of the rotating cam changes along with the movement of the central shaft, so that the end faces of all parts of the deformation area change along with the movement moment of the central rod at the moment; when the rotating cam rotates 90 degrees, the boundary extending distance of the internal rotating cam is longest, the height of the end face is smallest, and the asymmetric shearing caused by the built-in rotating cam is most severe; when the rotation angle of the rotating cam exceeds 90 degrees, the boundary extending part of the built-in rotating cam is gradually reduced, and the asymmetric shearing degree caused by the extending part is gradually reduced; when the built-in rotating cam rotates for a certain angle, the rotating boundary of the built-in rotating cam is completely rotated into the central rod, the asymmetric shearing degree caused by the built-in rotating cam is minimum, and the state of the built-in rotating cam is in mirror symmetry with the state at the beginning; as the center rod moves rightwards, the rotary cam continues to rotate, at the moment, the extending part of the rotary cam is in mirror symmetry with the extending part at 0-180 degrees, the movement state is the same, but the end face shape of the asymmetric shearing space formed by the different arc radiuses of the boundary of the rotary cam is different from the end face at 0-180 degrees, and the asymmetric shearing degree is different.
Further, the asymmetric internal rotation shearing area II is affected by the shape of the cavity of the female die to form asymmetric shearing, and the severe plastic deformation can effectively refine grains; meanwhile, the rotary cam rotates and moves rightwards, so that the shearing space of an asymmetric internal rotation shearing area II formed by the female die and the rotary cam is changed at moment, the end surface area is changed at moment with the height, the material in the deformation area is different in up-down flow velocity, asymmetric shearing is enhanced, and grains are greatly refined.
Further, the built-in rotating cam rotates in the pipe, so that the c-axis of the crystal grain deflects along the linear speed direction of the rotating cam, the texture of the strong base surface is effectively weakened, and meanwhile, the deflection directions of the c-axis of the crystal grain are opposite in the upper and lower directions of the pipe due to the opposite directions of the upper and lower linear speeds when the built-in rotating cam rotates, and the texture is greatly weakened.
Further, heating cotton is arranged outside the female die; the female die is connected with the left and right fixing plates through four bolts.
Further, the annular male die, the female die, the central rod, the rotary cam, the rack and the positioning frame are made of hot work die steel 4Cr5MoSiV1, wherein the inner diameter, the outer diameter, the length and the height of the annular male die, the female die, the central rod, the rotary cam and the positioning frame are different; the surface roughness of the annular male die, the female die, the central rod, the rotary cam, the rack and the positioning frame is Ra0.16-0.4 mu m.
The invention relates to a method for preparing a high-performance magnesium alloy pipe by asymmetric internal rotation extrusion, which comprises the following steps:
s1-1, polishing the inner surface and the outer surface of a magnesium alloy pipe by using 600-mesh sand paper to remove greasy dirt, and sequentially polishing by using 800-mesh, 1000-mesh and 1200-mesh sand paper until the surface of the magnesium alloy pipe is smooth;
s1-2, mixing acetone and absolute ethyl alcohol in a cleaning tank according to a volume ratio of 3:2, and uniformly stirring to prepare cleaning liquid;
s1-3, immersing the magnesium alloy pipe prepared in the step S1-1 into the cleaning solution prepared in the step S1-2, placing the cleaning tank on an ultrasonic cleaner to ultrasonically clean the magnesium alloy pipe for 60min, taking out the magnesium alloy pipe, cleaning the magnesium alloy pipe with absolute ethyl alcohol, and finally drying the magnesium alloy pipe by a blower;
s1-4, coating graphite oil solution on the inner and outer surfaces of the magnesium alloy pipe prepared in the step S1-3, and reserving for later use;
s2, preheating the magnesium alloy pipe: setting the heating temperature of a vacuum atmosphere heating furnace to be 450 ℃, and after the heating furnace temperature reaches the set temperature, placing the magnesium alloy pipe into the heating furnace, and preserving the heat for 3 hours;
s3, lubricating, assembling and preheating the asymmetric internal rotation extrusion forming device:
s3-1, lubrication: smearing graphite oil solution on the inner cavity of the female die, the inner surface and the outer surface of the annular male die, the inner surface and the outer surface of the central rod, the outer surface of the rack, the outer surface of the positioning frame and the outer surface of the rotary cam;
s3-2, assembling:
firstly, a female die is connected with a left baffle plate and a right baffle plate through bolts, the female die is mounted on a horizontal extruder, and heating cotton is surrounded around the female die; fixing an extrusion telescopic pressure head with an annular male die, extending the annular male die into a female die, and coaxially placing the annular male die and the female die; placing a rack into the center rod, then placing a rotary cam into a space corresponding to the inside of the center rod, meshing with the rack, and then stretching the center rod into the annular male die from the right end and contacting with the extrusion telescopic pressure head; connecting the positioning frame with the rack, extending out from the lower parts of the female die and the central rod, and fixing the positioning frame on the horizontal extruder;
s3-3, preheating: controlling the heating temperature to be 300-500 ℃, and preserving heat for 2-4 hours after the heating temperature reaches the set temperature for later use;
s4, asymmetric internal rotation extrusion forming: the space among the female die, the annular male die, the central rod and the rotary cam jointly forms a shearing extrusion space; the shearing extrusion space comprises a material placing area I, an asymmetric internal rotation shearing area II and a material discharging area III which are sequentially arranged from left to right;
s4-1, placing the magnesium alloy pipe on the right side of the annular male die and contacting the annular male die, then extruding the telescopic pressure head to push the annular male die, the central rod and the pipe into the female die rightwards, starting the motor to extrude the pipe into the shearing extrusion space when the pipe reaches the material placing area I, and enabling the central rod to move rightwards while enabling the rotary cam to start rotating under the meshing of the rack and the extending part of the rotary cam due to the fact that the rack is fixed; because the upper and lower shapes of the cavity of the female die are different, asymmetric shearing is formed, the rotating cam rotates and moves rightwards, so that the time of the up and down shearing extrusion space is changed, the end surface area and the height of the shearing extrusion space are changed, the asymmetric shearing is aggravated, and the heating temperature is controlled to be 300-500 ℃ in the asymmetric internal rotation extrusion forming process;
s4-2, controlling the pipe to be placed in a placing area I through a press, performing up-down asymmetric shearing deformation in an asymmetric internal rotation shearing area II, and finally finishing discharging in a discharging area III; asymmetric internal rotation extrusion deformation occurs, so that grains of each section of the magnesium alloy pipe are thinned and the texture is weakened; after the annular male die moves to the right to a certain distance, then a stop button is pressed to finish asymmetric internal rotation extrusion deformation of the magnesium alloy pipe, so that uniform high-performance magnesium alloy pipe with finer grains is obtained;
s4-3, taking out the magnesium alloy pipe manufactured in the step S4-2, polishing the surface of the magnesium alloy pipe by using sand paper, cleaning the magnesium alloy pipe by using the cleaning liquid manufactured in the step S1-2, and finally, secondarily cleaning by using absolute ethyl alcohol, and drying by using a blower to manufacture the high-performance magnesium alloy pipe capable of being directly put into use.
Compared with the prior art, the invention has the beneficial effects that:
1. the rotating cam rotates in the pipe, so that the c axis of the crystal grain of the pipe deflects along the linear speed direction of the rotating cam, the texture of the strong base surface is weakened, and the opposite direction of the upper and lower linear speeds of the rotating cam leads the c axis of the crystal grain of the pipe to deflect in opposite directions, so that the texture is greatly weakened, the anisotropism is reduced, and the comprehensive mechanical property of the magnesium alloy pipe is improved.
2. The cavity of the female die has different upper and lower shapes, and the material passes through the cavity in the extrusion process at different upper and lower flow rates, so that the cavity is sheared asymmetrically up and down, severe plastic deformation occurs, the grain refinement effect is obvious, and the obtained magnesium alloy pipe has more uniform structure.
3. The rotary cam rotates and moves rightwards, so that the shearing extrusion space formed by the rotary cam and the cavity of the female die is changed at moment, the end face area is changed at moment with the height, the material is different in flow velocity up and down, the up-down asymmetric shearing deformation is aggravated, the plastic deformation is more severe, crystal grains are thinned, the texture can be weakened effectively, and the mechanical property of the magnesium alloy pipe is improved.
Drawings
FIG. 1 is a schematic diagram of an apparatus for producing a high performance magnesium alloy pipe by asymmetric internal rotation extrusion in accordance with the present invention;
FIG. 2 is a graph showing the distribution of the deformed regions of FIG. 1;
FIG. 3 is a diagram showing the variation of the cavity in the deformation zone during the extrusion process;
FIG. 4 is a block diagram of an annular punch;
FIG. 5 is a block diagram of a rotating cam;
FIG. 6 is a block diagram of the right half of the center pole;
FIG. 7 is a block diagram of the left half of the center pole;
FIG. 8 is a block diagram of the cavity of the female die;
FIG. 9 is a view showing the internal and external states of the magnesium alloy pipe blank.
In the figure: 1-base, 2-horizontal extruder, 3-display screen, 4-pilot lamp, 5-switch, 6-heating switch, 7-flexible pressure head switch, 8-emergency brake switch, 9-connecting wire, 10-pressure motor base, 11-pressure motor, 12-pressure motor driving belt, 13-extrusion flexible cavity, 14-extrusion flexible pressure head, 15-annular male die, 16-locating rack, 17-rack, 18-center rod, 19-left baffle, 20-heating cotton, 21-female die, 22-rotating cam, 23-right baffle, 24-bolt, 25-magnesium alloy pipe.
I-a material placing area; II, an asymmetric internal rotation shearing area II; III-discharge zone.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples.
The device for preparing the high-performance magnesium alloy pipe by asymmetric internal rotation extrusion comprises an external die carrier, an asymmetric internal rotation shearing device and a power device, wherein:
the outer die carrier comprises a left baffle 19, a right baffle 23, a plurality of bolts 24 and heating cotton 20;
the asymmetric internal rotation shearing device comprises an annular male die 15, a female die 21, a central rod 18, a rotary cam 22, a rack 17 and a positioning frame 16; the female die 21 is horizontally provided with a left and right through cavity; the central rod 18 is provided with an inner space, the rotary cam 22 is arranged in the inner space of the central rod 18, the rotary cam 22 is axially horizontal and is axially vertical to the central rod, the inner space is vertically communicated with the outside, the inner space protrudes outwards at two axial sides of the rotary cam 22 to form a protruding part, the rotary cam 22 protrudes outwards axially, and a gear is arranged at the protruding part; the inner space of the central rod 18 also comprises a pair of long grooves which are formed in the direction parallel to the axial direction of the central rod, the right ends of the long grooves penetrate through the two protruding parts, and the central rod 18 is provided with a left space communicated with the left ends of the long grooves; the bottom of the annular male die 15 is provided with an opening;
the power device comprises a horizontal extruder 2, a pressure motor 11, an extrusion telescopic cavity 13 and an extrusion telescopic pressure head 14 which is connected with the extrusion telescopic cavity 13 and is horizontally arranged;
the left baffle plate and the right baffle plate are arranged on the horizontal extruder 2, the female die 21 is fixed between the left baffle plate and the right baffle plate, the left baffle plate and the right baffle plate are connected together through a plurality of bolts 24, the heating cotton 20 is coated around the female die 21, and through holes are formed in the positions, corresponding to the through holes of the female die 21, of the left baffle plate and the right baffle plate; the annular male die 15 is fixed with the extrusion telescopic pressure head 14, is coaxially arranged with the female die 21 and can extend into the female die 21 from the left end; the central rod 18 extends from the right end into the annular male die 15 and is placed coaxially with the female die 21; the rack 17 is transversely arranged in the long groove of the inner space of the central rod 18 and is meshed with a gear of the protruding part of the rotary cam 22; the positioning frame 16 extends into the left space of the center rod 18 from the opening at the bottom of the annular male die 15 to fix the rack 17; the spaces between the die 21, the annular punch 15, the central rod 18 and the rotating cam 22 together constitute a shear compression space.
Further, when the extrusion telescopic ram 14 pushes the annular male die 15 and the central rod 18 to move rightwards, the rack 17 is fixed by the positioning frame 16, the protruding part of the rotary cam 22 in the central rod 18 is meshed with the rack 17 to start rotating, the rotation angular velocity is omega, at this time, the upper and lower materials in the female die 21 start to perform asymmetric shearing under the condition that the upper and lower asymmetric shapes of the channel, and the relative flow rates of the upper and lower materials are different. The rotary cam 22 rotates and moves rightward at the same time, and the die 21 is fixed so that the shearing end face formed by the upper and lower parts of the rotary cam 22 and the inner wall of the die 21 is changed at any time. Because the rotation of the rotary cam 22 causes the pipe to be sheared up and down in the opposite direction, the shearing is promoted in the same direction as the movement of the central rod 18, and the shearing is restrained in the opposite direction as the central rod 18, so that the texture of the strong base surface is weakened effectively, unlike the shearing degree in the up and down direction.
Further, the inner space of the central rod 18 is used for accommodating the part of the rotary cam 22, and the part of the inner space is in an arc shape along the two sides of the axial direction of the central rod 18 to form a circular track, and the inner cavity of the female die 21 is connected with the inner wall corresponding to the rotary cam 22 in a wave-shaped mechanism in which a plurality of sections of arcs with different radiuses are formed.
When the center rod 18 moves rightward with the annular punch 15, the rack 17 is fixed by the positioning frame 16, and the rotating cam 22 rotates counterclockwise under engagement of the rack 17. At the beginning, because the right movement distance of the central rod 18 is limited, the rotation angle of the rotary cam 22 is smaller, the boundary of the rotary cam 22 can not extend out of the central rod 18, and at the moment, asymmetric shearing deformation extrusion is mainly carried out by the difference of the upper arc radius and the lower arc radius of the inner cavity of the female die 21; when the central rod 18 moves a certain distance, the two sides of the boundary of the rotary cam 22 extend upwards and downwards out of the central rod 18 respectively when the rotary cam 22 rotates to a certain angle, and at the moment, the asymmetric shear deformation is greatly aggravated by the fact that the boundary of the rotary cam 22 extends out of the central rod 18 except that the radii of the upper arc and the lower arc of the inner cavity of the female die 21 are different. The shape of the end face of the deformation space is formed by the inner cavity of the female die 21 and the rotary cam 22, and the rotation angle of the rotary cam 22 changes along with the movement of the central shaft, so that the end faces of all parts of the deformation area change along with the movement moment of the central rod 18 at the moment; when the rotating cam 22 rotates 90 degrees, the boundary of the inner rotating cam 22 extends out the longest distance, the height of the end face is the smallest, and the asymmetric shearing caused by the inner rotating cam 22 is the most severe; when the rotation angle of the rotating cam 22 exceeds 90 degrees, the protruding part of the boundary of the built-in rotating cam 22 is gradually reduced, and the degree of asymmetric shearing caused by the protruding part is gradually reduced; when the built-in rotary cam 22 rotates for a certain angle, the rotation boundary of the built-in rotary cam 22 is completely turned into the center rod 18, and the asymmetric shearing degree caused by the built-in rotary cam 22 is minimum at the moment, and the state of the built-in rotary cam is in mirror symmetry with the state at the beginning; as the center rod 18 moves rightward, the rotating cam 22 continues to rotate, and at this time, the protruding portion of the rotating cam 22 is mirror-symmetrical to the protruding portion at 0 ° to 180 °, and the moving state is the same, but the end face shape of the asymmetric shearing space formed by the difference of the radius of the boundary circular arc of the rotating cam 22 is different from the end face at 0 ° to 180 ° of rotation, so that the degree of asymmetric shearing is different.
Further, the extrusion space comprises a material placing area I, an asymmetric internal rotation shearing area II and a discharging area III which are sequentially arranged from left to right, the material placing area I is used for placing the original magnesium alloy pipe 25, the symmetric shearing area II is used for carrying out up-down asymmetric shearing, meanwhile, the rotating cam 22 is rotated and moves rightward so that the up-down shearing end face is changed at any time, and the discharging area III is used for extruding the magnesium alloy pipe 25 in the asymmetric internal rotation shearing area II. The device can realize the deformation preparation of the high-performance magnesium alloy pipe by asymmetric internal rotation extrusion preparation of the high-performance magnesium alloy pipe.
Further, the asymmetric internal rotation shearing area II is affected by the shape of the inner cavity of the female die 21 to form asymmetric shearing, and the severe plastic deformation can effectively refine grains; meanwhile, the rotary cam 22 rotates and moves rightwards, so that the shearing space of an asymmetric internal rotation shearing area II formed by the female die 21 and the rotary cam 22 is changed at moment, the end surface area and the height are changed at moment, the material in the deformation area is different in up-down flow velocity, asymmetric shearing is enhanced, and grains are greatly refined.
Further, the built-in rotating cam 22 rotates inside the magnesium alloy pipe 25, so that the c-axis of the crystal grains deflects along the linear speed direction of the rotating cam 22, the strong base surface texture is effectively weakened, and meanwhile, the c-axis deflection directions of the upper and lower crystal grains of the magnesium alloy pipe 25 are opposite due to the opposite upper and lower linear speed directions when the built-in rotating cam 22 rotates, and the texture is greatly weakened.
Further, heating cotton is arranged outside the female die 21; the female die 21 is connected with the left and right fixing plates through four bolts.
Further, the annular male die 15, the female die 21, the central rod 18, the rotary cam 22, the rack 17 and the positioning frame 16 are made of hot work die steel 4Cr5MoSiV1, wherein the inner diameter, the outer diameter, the length and the height of the annular male die 15, the female die 21, the central rod 18, the rotary cam 22 and the positioning frame 16 are different; the surface roughness of the annular male die 15, the female die 21, the central rod 18, the rotary cam 22, the rack 17 and the positioning frame 16 is Ra0.16-0.4 mu m.
The outer diameter of the annular male die 15 is D 1 An inner diameter of D 2 Length ofl 1 The opening length of the annular male die 15 isl 2 Wide isl 3 The method comprises the steps of carrying out a first treatment on the surface of the The length of the rotary cam 22 isl 4 Wide asl 5 The width of the protruding part rack isl 6 The outer diameter of the protruding part is D 3 An inner diameter of D 4 The external circle radius is R respectively 1 And R is 2 The method comprises the steps of carrying out a first treatment on the surface of the The central rod 18 has a length ofl 8 The inner space portion accommodating the rotary gear 22 has a length ofl 7 The length of the central rod 18 isl 9 The radius of the circular track inside the central rod 18 is R 3 The radius of the protruding portion of the inner space of the central rod 18 is R 4 The method comprises the steps of carrying out a first treatment on the surface of the The radius of the upper part of the cavity of the female die 21 is R respectively 5 、R 6 、R 7 The lower radius is R 8 、R 9 And R is 10 The movement distance length of the annular male die 18 in the female die 21 isl 10 The method comprises the steps of carrying out a first treatment on the surface of the Wherein R is 1 ≠R 2 ≠R 3 ≠R 4 ≠R 5 ≠R 6 ≠R 7 ≠R 8 ≠R 9 ≠R 10 ，R 3 ＞R 2 ＞R 1 ，D 1 ≠D 2 ≠D 3 ≠D 4 ，l 1 ≠l 2 ≠l 3 ≠l 4 ≠l 5 ≠l 6 ≠l 7 ≠l 8 ≠l 9 ≠l 10 。
In the specific embodiment, materials and chemical reagents required in the preparation process are selected before the asymmetric internal rotation extrusion is carried out to prepare the high-performance magnesium alloy pipe:
1. magnesium alloy pipe 25: AZ31 is selected as a pipe material, 96% of magnesium, 3% of aluminum and 1% of zinc are contained;
2. sand paper, solid solids;
3. graphite oil solution, viscous liquid;
4. absolute ethyl alcohol, liquid with purity of 99.5%;
5. acetone, liquid, 99% pure.
A method for preparing a high-performance magnesium alloy pipe by adopting the asymmetric internal rotation extrusion device comprises the following steps:
s1, pretreatment of a magnesium alloy pipe 25:
s1-1, polishing the surface of the magnesium alloy pipe 25 by using 600-mesh sand paper to remove greasy dirt, and sequentially polishing the surface of the magnesium alloy pipe 25 by using 800-mesh, 1000-mesh and 1200-mesh sand paper until the surface of the magnesium alloy pipe 25 is smooth;
s1-2, mixing acetone and absolute ethyl alcohol in a cleaning tank according to a volume ratio of 3:2, and uniformly stirring to prepare cleaning liquid;
s1-3, immersing the magnesium alloy pipe 25 prepared in the step S1-1 into the cleaning solution prepared in the step S1-2, placing a cleaning tank on an ultrasonic cleaner to ultrasonically clean the magnesium alloy pipe 25 for 60min, taking out the magnesium alloy pipe 25, cleaning with absolute ethyl alcohol, and finally drying with a blower;
s1-4, coating graphite oil solution on the surface of the magnesium alloy pipe 25 prepared in the step S1-3 for later use;
s2, preheating the magnesium alloy pipe 25: setting the heating temperature of a vacuum atmosphere heating furnace to 450 ℃, and after the heating furnace temperature reaches the set temperature, placing the magnesium alloy pipe 25 into the heating furnace, and preserving the heat for 3 hours;
s3, lubricating, assembling and preheating the asymmetric internal rotation extrusion forming device:
s3-1, lubrication: the inner and outer surfaces of the annular male die 15, the inner cavity of the female die 21, the inner and outer surfaces of the center rod 18, the outer surface of the rotary cam 22 and the surface of the rack 17 are coated with graphite oil solution;
s3-2, assembling:
firstly, the female die 21 is connected with the left baffle 19 and the right baffle 23 by bolts 24 and fixed on the horizontal extruder 2, the annular male die 15 is fixed on the extrusion telescopic ram 14, the rotary cam 22 is assembled into the central rod 18, meanwhile, the right end of the rack 17 extends into the inner space of the central rod 18, the central rod 18 extends into the leftmost end from the right end of the annular male die 15, the left end of the rack 17 is fixed on the positioning frame 16, the positioning frame 16 extends out of the inner space of the central rod 18 and the annular male die 15 and is fixed on the horizontal extruder 2, the original magnesium alloy pipe 25 is sleeved in from the right end of the central rod 18, the magnesium alloy pipe 25 is contacted with the female die 21, the annular male die 15 and the female die 21 are coaxially placed, and the heating cotton 20 is wound around the female die 21.
S3-3, preheating: operating a heating switch 6 to control the temperature of the heating cotton 20 to be 300-500 ℃, and preserving heat for 2-4 hours after the temperature reaches a set temperature for later use;
s4, asymmetric internal rotation extrusion forming: the female die 21, the central rod 18, the rotary cam 22 and the annular male die 15 are connected together to form an asymmetric shearing extrusion space; the torsion extrusion space comprises a material placing area I, an asymmetric internal rotation shearing area II and a material discharging area III which are sequentially arranged from left to right;
s4-1, pushing the annular male die 15 rightwards to enable the magnesium alloy pipe 25 to be placed in the material placing area I, and then continuing to operate the annular male die 15 to push the annular male die rightwards at the speed v; in the extrusion process, the shape of the cavity of the female die 21 is different from the shape of the cavity of the female die, and the magnesium alloy pipe 25 is subjected to up-down asymmetric shear deformation; simultaneously, the center rod 18 moves rightwards under the drive of the annular male die 15, the rotary cam 22 moves rightwards under the drive of the center rod 18, and the rotary cam rotates under the engagement of the protruding parts of the rack 17 and the rotary cam 22 due to the fact that the rack 17 is fixed by the positioning frame 16, and the rotation angular speed is omega. The rotation of the rotary cam 22 and the rightward movement of the rotary cam 22 driven by the central rod 18 change the up-down asymmetric shearing space moment, exacerbate the asymmetric shearing and refine the grains; because the rotation of the rotary cam 22 causes the pipe to generate a reverse shearing action up and down, the c axis of the crystal grains of the magnesium alloy pipe 25 deflects along the linear speed direction of the rotary cam 22, the shearing in the same direction as the movement of the central rod 18 is promoted, the shearing in the reverse direction as the central rod 18 is restrained, the deflection degree of the upper crystal grains and the lower crystal grains of the magnesium alloy pipe 25 is different, and the strong basal plane texture is effectively weakened. In the asymmetric internal rotation extrusion forming process, controlling the temperature of the heating switch 6 to be 300-500 ℃;
s4-2, controlling the pipe to perform asymmetric shearing extrusion deformation in an asymmetric internal rotation shearing area II through a press, and finally finishing discharging in a discharging area III. Asymmetric shearing extrusion deformation occurs, so that grains of each section of the magnesium alloy pipe are thinned; after the annular male die 15 is displaced to a certain extent, a stop button is pressed, and the deformation process of the pipe into a thin-wall pipe is completed.
S4-3, taking out the magnesium alloy pipe 25 prepared in the step S4-2, polishing the surface of the magnesium alloy pipe by using sand paper, cleaning the magnesium alloy pipe 25 by using the cleaning liquid prepared in the step S1-2, and finally, secondarily cleaning by using absolute ethyl alcohol, and drying by using a blower to prepare the high-performance magnesium alloy pipe capable of being directly put into use.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
A process method for preparing high-performance magnesium alloy pipe by asymmetric internal rotation extrusion adopts the following steps:
(1) The external die carrier and the asymmetric internal rotation shearing device are arranged on the horizontal hydraulic extruder, the installation is firm, the positions of all parts are required to be correctly connected, and the sequential operation is required;
(2) Polishing the inner and outer surfaces of an AZ31 magnesium alloy pipe blank by using 600-mesh sand paper to remove greasy dirt, and then sequentially polishing by using 1000, 1200 and 2500-mesh sand paper to ensure that the surfaces are clean and smooth; placing the polished magnesium alloy block blank into a mixed solution of acetone and absolute ethyl alcohol in a volume ratio of 3:2 for ultrasonic cleaning for 30min, and then cleaning with alcohol and drying with a blower;
(3) Starting a vacuum atmosphere heating furnace to preheat the magnesium alloy pipe blank, wherein the preset temperature is 400 ℃, and continuously placing the magnesium alloy block blank into the heating furnace to keep the temperature for 3 hours when the preset temperature is reached;
(4) Starting a heating device to heat the asymmetric internal rotation shearing area, wherein the heating temperature is preset to 400 ℃, and keeping the temperature for 3 hours after the heating temperature reaches the preset temperature;
(5) And (3) coating a high-temperature graphite oil solution on the surface of the magnesium alloy block pipe blank for lubrication, and starting the motor to place the preheated magnesium alloy pipe blank in a material placing area I by using an annular male die. The materials of the annular male die 15, the female die 21, the central rod 18, the rotary cam 22, the rack 17 and the positioning frame 16 are all hot work die steel 4Cr5MoSiV1, and the surface roughness of the annular male die 15, the female die 21, the central rod 18, the rotary cam 22, the rack 17 and the positioning frame 16 is Ra0.3μm.
(6) The motor is started, the annular male die 15 moves rightwards under the action of the pressure motor 11, and the speed of the annular male die is higher than that of the annular male dievAbout 200mm/min; in extrusionIn the process, the shape of the cavity of the female die 21 is different from the shape of the cavity of the female die, and the magnesium alloy pipe 25 is subjected to up-down asymmetric shearing deformation; simultaneously, the center rod 18 moves rightwards under the drive of the annular male die 15, the rotary cam 22 moves rightwards under the drive of the center rod 18, and the rotary cam rotates under the engagement of the protruding parts of the rack 17 and the rotary cam 22 due to the fact that the rack 17 is fixed by the positioning frame 16, and the rotation angle speed is about 40r/min. The rotation of the rotary cam 22 and the rightward movement of the rotary cam 22 driven by the central rod 18 change the asymmetric internal rotation shearing space moment, thereby exacerbating the asymmetric shearing; because the rotation of the rotary cam 22 causes the pipe to be sheared up and down in the opposite direction, the shearing is promoted in the same direction as the movement of the central rod 18, and the shearing is restrained in the opposite direction as the central rod 18, so that the texture of the strong base surface is weakened effectively, unlike the shearing degree in the up and down direction.
(7) After the annular male die 15 is displaced to a certain extent, a stop button is pressed, and the deformation process of the pipe into a thin-wall pipe is completed. The heating switch is turned off and the annular punch 15 is withdrawn.
(8) Taking out the magnesium alloy pipe 25, polishing the surface of the magnesium alloy pipe by using sand paper, then placing the magnesium alloy pipe in a mixed solution of acetone and absolute ethyl alcohol in a volume ratio of 3:2 for ultrasonic cleaning, and finally cleaning the magnesium alloy pipe by using alcohol and drying the magnesium alloy pipe by using a blower to blow.
Conclusion: the invention relates to a device and a process method for preparing a high-performance magnesium alloy pipe by asymmetric internal rotation extrusion, which are characterized in that the average grain size of a magnesium alloy blank is greatly reduced compared with that of a conventional magnesium alloy through up-and-down asymmetric shearing and severe plastic deformation, the original grain size is reduced to 1.52 mu m from 33 mu m, the up-and-down texture is asymmetrically weakened, the base surface texture is changed from a strong base surface texture to a deflected weak base surface texture, and the texture is effectively weakened compared with that of an initial magnesium alloy pipe.
The materials and chemical reagents used are as follows: AZ31 magnesium alloy tube stock, with an outer diameter d=100 mm, and an inner diameter d=60 mm; sand paper: siC,600 meshes, 2 sheets; 1000 meshes, 2 sheets; 1200 meshes, 2 sheets; 2500 meshes, 2 sheets; high temperature graphite oil solution: c,500g; absolute ethyl alcohol: CH (CH) 3 CH 2 OH,1200ml; acetone: c (C) 3 H 6 O，800ml。
The principle of the invention for obtaining the high-performance magnesium alloy pipe through the steps is described in detail below with reference to the accompanying drawings:
starting a motor, enabling the annular male die 15 to move rightward under the action of the pressure motor 11, enabling the speed of the annular male die to be v, and pushing the original magnesium alloy pipe 25 into an asymmetric internal rotation shearing area II; in the extrusion process, the magnesium alloy pipe 25 is subjected to up-down asymmetric shearing deformation and asymmetric shearing plastic deformation under the different upper and lower shapes of the cavity of the female die 21, and the grain structure is subjected to severe plastic deformation and grain refinement. Simultaneously, the center rod 18 moves rightwards under the drive of the annular male die 15, the rotary cam 22 moves rightwards under the drive of the center rod 18, and the rotary cam rotates under the engagement of the protruding parts of the rack 17 and the rotary cam 22 due to the fact that the rack 17 is fixed by the positioning frame 16, and the rotation angular speed is omega. The rotation of the rotary cam 22 and the rightward movement of the rotary cam 22 driven by the central rod 18 cause the change of the up-down asymmetric shearing space moment, which aggravates the asymmetric shearing; because the rotation of the rotary cam 22 causes the pipe to perform the up-down reverse shearing action, the shearing action in the same direction as the movement of the central rod 18 is promoted, the shearing action in the reverse direction as the central rod 18 is restrained, the up-down shearing degree is different, the texture of the strong base surface is effectively weakened, the anisotropism is reduced, the performance of the magnesium alloy material is improved, the mechanical property is effectively improved, and the high-performance magnesium alloy pipe is obtained.
The assembly of the asymmetric internal rotation extrusion die is shown in fig. 1. In the extrusion process, the shape of the cavity of the female die 21 is different from the upper and lower shapes, the magnesium alloy pipe 25 is subjected to up-down asymmetric shearing deformation, asymmetric shearing plastic deformation and grain refinement of the grain structure due to severe plastic deformation. Simultaneously, the center rod 18 moves rightwards under the drive of the annular male die 15, the rotary cam 22 moves rightwards under the drive of the center rod 18, and the rotary cam rotates under the engagement of the protruding parts of the rack 17 and the rotary cam 22 due to the fact that the rack 17 is fixed by the positioning frame 16, and the rotation angular speed is omega. The deformation area is composed of an annular male die 15, a female die 21 and a rotary cam 22, and is provided with a material placing area I, an asymmetric internal rotation shearing area II and a material discharging area III which are arranged in sequence from left to right as shown in figure 2Three regions. As shown in fig. 3, the movement speed of the annular punch 15 and the central rod 18 is v in the extrusion process, and the movement direction is shown in the figure; the angular velocity of the rotating cam 22 is ω and the direction of rotation is shown; as the central rod 18 moves to the right, the rotary cam 22 rotates, from top to bottom, by the deformation zones of 0 °, 45 °, 90 °,120 ° and 180 °, respectively, of the rotary cam 22, x 1 、x 2 、x 3 、x 4 And x 5 The distance x between the female die 21 and the left end face of the central rod 18 when the rotary cam 22 rotates by 0 °, 45 °, 90 °,120 ° and 180 °, respectively 1 、x 2 、x 3 、x 4 And x 5 The difference between (a) and (b) is the distance of movement of the center rod 18 when the rotating cam 22 rotates by a corresponding angle. FIG. 4 is a block diagram of the annular punch 15 and shows the relative movement space of the reserved retainer 16 inside the annular punch 15, of lengthl 2 . FIG. 6 is a block diagram of the right half of the center pole 18, showing a space view of the rack 17 inside the center pole 18, the rack 17 being of a lengthl 9 . Fig. 7 is a block diagram of the left half of the center rod 18 with openings for placement of the locating clip and rack. In fig. 9, the blank diagrams of the magnesium alloy pipe when the center rod 18 moves different distances and the rotating cam 22 rotates by different angles in the moving process are A, B, C, D and E respectively the blank diagrams when the rotating cam 22 rotates by 0 °, 45 °, 90 °,120 ° and 180 °, and the asymmetric shearing space time changes and the shearing end face also changes along with the rotation and the movement of the rotating cam 22. The rotating cam 22 rotates clockwise, so that the c axis of the crystal grain of the pipe deflects along the linear speed direction of the rotating cam 22, and as the rotating linear speed of the rotating cam 22 is opposite to the rotating linear speed, the acting forces on the two sides of the pipe are opposite, so that the deflection degree of the crystal grain on the two sides is larger, the shearing in the same direction with the movement of the central rod 18 is promoted, the shearing in the opposite direction with the central rod 18 is restrained, the deflection degree of the crystal grain on the side with the movement of the central rod 18 is larger, the deflection degree of the crystal grain on the side with the movement of the central rod 18 is smaller, and the weakening effect of the texture is more obvious.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present invention should be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (5)

1. The device for preparing the high-performance magnesium alloy pipe by asymmetric internal rotation extrusion is characterized by comprising an external die carrier, an asymmetric internal rotation shearing device and a power device, wherein:
the external die carrier comprises a left baffle (19), a right baffle (23), a plurality of bolts (24) and heating cotton (20);
the asymmetric internal rotation shearing device comprises an annular male die (15), a female die (21), a central rod (18), a rotary cam (22), a rack (17) and a positioning frame (16); the female die (21) is horizontally provided with a cavity which is penetrated left and right; the central rod (18) is provided with an inner space, the rotary cam (22) is arranged in the inner space of the central rod (18), the rotary cam (22) is axially horizontal and is axially vertical to the central rod (18), the inner space is vertically communicated with the outside, the inner space protrudes outwards to form protruding parts at two sides of the axial direction of the rotary cam (22), and the rotary cam (22) protrudes outwards axially and the protruding parts are provided with gears; the inner space of the central rod (18) also comprises a pair of long grooves which are formed in the direction parallel to the axial direction of the central rod (18), the right ends of the pair of long grooves respectively penetrate through the two protruding parts, and the central rod (18) is provided with a left space communicated with the left ends of the long grooves; an opening is arranged at the bottom of the annular male die (15);
the power device comprises a horizontal extruder (2), a press motor (11), an extrusion telescopic cavity (13) and an extrusion telescopic pressure head (14) which is connected with the extrusion telescopic cavity (13) and is horizontally arranged;
the left baffle plate and the right baffle plate are arranged on the horizontal extruder (2), the female die (21) is fixed between the left baffle plate and the right baffle plate, the left baffle plate and the right baffle plate are connected together through a plurality of bolts (24), the heating cotton (20) is coated around the female die (21), and through holes are formed in the positions, corresponding to the inner cavities of the female die (21), of the left baffle plate and the right baffle plate; the annular male die (15) is fixed with the extrusion telescopic pressure head (14), is coaxially arranged with the female die (21) and can extend into the female die (21) from the left end; the center rod (18) extends into the annular male die (15) from the right end and is coaxially arranged with the female die (21); the rack (17) is transversely arranged in the long groove of the inner space of the central rod (18) and is meshed with the gear of the protruding part of the rotary cam (22); the positioning frame (16) extends into the left space of the center rod (18) from the opening at the bottom of the annular male die (15) to fix the rack (17); the spaces among the female die (21), the annular male die (15), the central rod (18) and the rotary cam (22) jointly form a shearing extrusion space.
2. The device for preparing the high-performance magnesium alloy pipe by asymmetric internal rotation extrusion according to claim 1, wherein the inner space of the central rod (18) is used for accommodating the part of the rotary cam (22) and is in an arc shape along the two axial sides of the central rod (18) to form a circular track, and the inner cavity of the female die (21) and the inner wall corresponding to the rotary cam (22) are in a wavy structure with multiple sections of arc connection with different radiuses.
3. An apparatus for producing a high-performance magnesium alloy pipe by asymmetric internal rotation extrusion as claimed in claim 1 or 2, wherein the annular male die (15) has an outer diameter D 1 An inner diameter of D 2 Length ofl 1 The opening length of the annular male die (15) isl 2 Wide isl 3 The method comprises the steps of carrying out a first treatment on the surface of the The length of the rotary cam (22) isl 4 Wide asl 5 The width of the protruding part rack isl 6 The outer diameter of the protruding part is D 3 An inner diameter of D 4 The external circle radius is R respectively 1 And R is 2 The method comprises the steps of carrying out a first treatment on the surface of the The length of the central rod (18) isl 8 The inner space part for accommodating the rotary gear (22) has a length ofl 7 The length of the long groove of the central rod (18) isl 9 The radius of the circular orbit inside the central rod (18) is R 3 The radius of the inner protruding part of the central rod (18) is R 4 The method comprises the steps of carrying out a first treatment on the surface of the The inner cavity of the female die (21) and the radius of the upper part of the inner wall corresponding to the rotary cam (22) are respectively R 5 、R 6 、R 7 The lower radius is R 8 、R 9 And R is 10 The movement distance length of the annular male die (18) on the female die (21) is as followsl 10 The method comprises the steps of carrying out a first treatment on the surface of the Wherein R is 1 ≠R 2 ≠R 3 ≠R 4 ≠R 5 ≠R 6 ≠R 7 ≠R 8 ≠R 9 ≠R 10 ，R 3 ＞R 2 ＞R 1 ，D 1 ≠D 2 ≠D 3 ≠D 4 ，l 1 ≠l 2 ≠l 3 ≠l 4 ≠l 5 ≠l 6 ≠l 7 ≠l 8 ≠l 9 ≠l 10 。
4. The device for preparing the high-performance magnesium alloy pipe by asymmetric internal rotation extrusion according to claim 3, wherein the annular male die (15), the female die (21), the central rod (18), the rotary cam (22), the rack (17) and the positioning frame (16) are made of hot work die steel 4Cr5MoSiV1; the surface roughness of the annular male die (15), the female die (21), the central rod (18), the rotary cam (22), the rack (17) and the positioning frame (16) is Ra0.16-0.4 mu m.
5. A process method for preparing a high-performance magnesium alloy pipe by asymmetric internal rotation extrusion is characterized by comprising the following steps of S1, preprocessing the magnesium alloy pipe:
s1-1, polishing the inner surface and the outer surface of a magnesium alloy pipe (25) by using 600-mesh sand paper to remove greasy dirt, and sequentially polishing by using 800-mesh sand paper, 1000-mesh sand paper and 1200-mesh sand paper until the surface of the magnesium alloy pipe (25) is smooth;
s1-2, mixing acetone and absolute ethyl alcohol in a cleaning tank according to a volume ratio of 3:2, and uniformly stirring to prepare cleaning liquid;
s1-3, immersing the magnesium alloy pipe (25) prepared in the step S1-1 into the cleaning liquid prepared in the step S1-2, placing the cleaning tank on an ultrasonic cleaner to ultrasonically clean the magnesium alloy pipe (25) for 60min, then taking out the magnesium alloy pipe (25), cleaning with absolute ethyl alcohol, and finally drying with a blower;
s1-4, coating graphite oil solution on the inner and outer surfaces of the magnesium alloy pipe (25) prepared in the step S1-3 for later use;
s2, preheating the magnesium alloy pipe: setting the heating temperature of a vacuum atmosphere heating furnace to be 450 ℃, and after the heating furnace temperature reaches the set temperature, placing a magnesium alloy pipe (25) into the heating furnace, and preserving the heat for 3 hours;
s3, lubricating, assembling and preheating the asymmetric internal rotation extrusion forming device:
s3-1, lubrication: smearing graphite oil solution on the inner cavity of the female die (21), the inner and outer surfaces of the annular male die (15), the inner and outer surfaces of the central rod (18), the outer surface of the rack (17), the outer surface of the positioning frame (16) and the outer surface of the rotary cam (22);
s3-2, assembling:
firstly, connecting a female die (21) with a left baffle plate (19) and a right baffle plate (23) by bolts (24), installing the female die on a horizontal extruder (2), and surrounding a heating cotton (20) around the female die (21); fixing an extrusion telescopic pressure head (14) with an annular male die (15), extending the annular male die (15) into a female die (21), and coaxially placing the annular male die and the female die (21); placing a rack (17) into the central rod (18), then placing a rotary cam (22) into a space corresponding to the interior of the central rod (18) and meshed with the rack (17), and then extending the central rod (18) into the annular male die (15) from the right end and contacting with the extrusion telescopic pressure head (14); the positioning frame (16) is connected with the rack (17) and extends out from the lower parts of the female die (21) and the central rod (18) and is fixed on the horizontal extruder (2);
s3-3, preheating: controlling the heating temperature to be 300-500 ℃, and preserving heat for 2-4 hours after the heating temperature reaches the set temperature for later use;
s4, asymmetric internal rotation extrusion forming: the space among the female die (21), the annular male die (15), the central rod (18) and the rotary cam (22) jointly forms a shearing extrusion space; the shearing extrusion space comprises a material placing area I, an asymmetric internal rotation shearing area II and a material discharging area III which are sequentially arranged from left to right;
s4-1, placing a magnesium alloy pipe (25) on the right side of an annular male die (15) and contacting the annular male die, then extruding a telescopic pressure head (14) to push the annular male die (15), a central rod (18) and the pipe into a female die (21) rightwards, stopping when the pipe reaches a material placing area I, starting a motor to extrude the pipe into a shearing extrusion space, enabling the central rod (18) to move rightwards, and simultaneously enabling a rotating cam (22) to start rotating under the engagement of a protruding part of the rotating cam (22) and a rack (17) due to the fact that the rack (17) is fixed; because the upper and lower shapes of the inner cavity of the female die (21) are different, asymmetric shearing is formed, the rotary cam (22) rotates and moves rightwards, so that the time of the up and down shearing extrusion space is changed, the end surface area and the height of the shearing extrusion space are changed, the asymmetric shearing is aggravated, and the heating temperature is controlled to be 300-500 ℃ in the asymmetric internal rotation extrusion forming process;
s4-2, controlling the pipe to be placed in a placing area I through a press, performing up-down asymmetric shearing deformation in an asymmetric internal rotation shearing area II, and finally finishing discharging in a discharging area III; asymmetric internal rotation extrusion deformation occurs, so that each section of crystal grain of the magnesium alloy pipe (25) is thinned and the texture is weakened; after the annular male die (15) moves to the right to a certain distance, then a stop button is pressed to finish asymmetric internal rotation extrusion deformation of the magnesium alloy pipe (25) so as to obtain a uniform high-performance magnesium alloy pipe (25) with finer grains;
s4-3, taking out the magnesium alloy pipe (25) prepared in the step S4-2, polishing the surface of the magnesium alloy pipe by using sand paper, cleaning the magnesium alloy pipe by using the cleaning liquid prepared in the step S1-2, and finally, secondarily cleaning by using absolute ethyl alcohol, and drying by using a blower to prepare the high-performance magnesium alloy pipe capable of being directly put into use.
CN202211570734.4A 2022-12-08 2022-12-08 Device and process method for preparing high-performance magnesium alloy pipe by asymmetric internal rotation extrusion Pending CN116060468A (en)

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