CN117358767A - Device and method for preparing fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion - Google Patents
Device and method for preparing fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion Download PDFInfo
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- CN117358767A CN117358767A CN202311539093.0A CN202311539093A CN117358767A CN 117358767 A CN117358767 A CN 117358767A CN 202311539093 A CN202311539093 A CN 202311539093A CN 117358767 A CN117358767 A CN 117358767A
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- 238000001125 extrusion Methods 0.000 title claims abstract description 805
- 229910000861 Mg alloy Inorganic materials 0.000 title claims abstract description 161
- 238000000034 method Methods 0.000 title claims abstract description 32
- 238000005096 rolling process Methods 0.000 title claims abstract description 17
- 238000010008 shearing Methods 0.000 claims abstract description 19
- 230000009471 action Effects 0.000 claims abstract description 17
- 238000013329 compounding Methods 0.000 claims abstract description 10
- 230000005540 biological transmission Effects 0.000 claims description 57
- 238000004140 cleaning Methods 0.000 claims description 26
- 238000010438 heat treatment Methods 0.000 claims description 25
- 230000006835 compression Effects 0.000 claims description 20
- 238000007906 compression Methods 0.000 claims description 20
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 18
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 16
- 244000137852 Petrea volubilis Species 0.000 claims description 15
- 230000003746 surface roughness Effects 0.000 claims description 14
- 238000005498 polishing Methods 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 10
- 238000001035 drying Methods 0.000 claims description 8
- 229910002804 graphite Inorganic materials 0.000 claims description 8
- 239000010439 graphite Substances 0.000 claims description 8
- 239000011248 coating agent Substances 0.000 claims description 7
- 238000000576 coating method Methods 0.000 claims description 7
- 239000007788 liquid Substances 0.000 claims description 7
- 229910000831 Steel Inorganic materials 0.000 claims description 4
- 238000005461 lubrication Methods 0.000 claims description 4
- 239000010959 steel Substances 0.000 claims description 4
- 238000009434 installation Methods 0.000 claims description 3
- 230000001050 lubricating effect Effects 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 238000003756 stirring Methods 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 abstract description 5
- 239000002184 metal Substances 0.000 abstract description 5
- 230000003313 weakening effect Effects 0.000 abstract description 4
- 239000000243 solution Substances 0.000 description 8
- 239000003921 oil Substances 0.000 description 7
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 6
- 229910052749 magnesium Inorganic materials 0.000 description 6
- 239000011777 magnesium Substances 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 239000000956 alloy Substances 0.000 description 4
- 238000005275 alloying Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 238000004506 ultrasonic cleaning Methods 0.000 description 3
- 238000003723 Smelting Methods 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 235000019441 ethanol Nutrition 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000003672 processing method Methods 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000010705 motor oil Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
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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
- B21C23/001—Extruding metal; Impact extrusion to improve the material properties, e.g. lateral extrusion
-
- 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
-
- 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
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Extrusion Of Metal (AREA)
Abstract
The invention belongs to the technical field of light metal plastic processing and mechanical property increasing, and particularly relates to a device and a method for preparing a fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion compounding. The device comprises a power device, a reciprocating extrusion device, a differential rotary extrusion device, a horizontal extruder, an extrusion die and a bracket. The left extrusion channel, the differential rotation extrusion channel and the right extrusion channel jointly form a reciprocating rotation differential extrusion channel. According to the invention, the differential rotary extrusion channel deflects the C axis of the magnesium alloy, so that the basal plane texture of the magnesium alloy is effectively weakened, grains are refined, and the mechanical property of the magnesium alloy is improved; the thickness of the extrusion channel tends to be reduced, the pipe is subjected to pressure between the extrusion channel walls which are gradually thinned after entering from the feeding hole, and meanwhile, under the action of the internal and external rotary extrusion cylinders, the pipe is subjected to the action of shearing force along the radial direction, and the shearing force can be controlled by adjusting the friction coefficient of the outer wall of the extrusion cylinder. The weakening effect of the grain texture of the magnesium alloy bar is more obvious.
Description
Technical Field
The invention belongs to the technical field of light metal plastic processing and mechanical property increasing, and particularly relates to a device and a method for preparing a fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion compounding.
Background
In recent years, magnesium and magnesium alloys have received extensive attention for their unique and excellent comprehensive mechanical properties, and are currently the lightest metal structural materials. Because magnesium and magnesium alloys have excellent performance characteristics, for example: the magnesium alloy has excellent application prospect, and has been widely used in the fields of military, aerospace, digital electronic products and the like. Meanwhile, the high-performance magnesium alloy thin-wall pipe is widely applied to the fields of national defense, traffic and the like as a hollow section, is an important magnesium alloy structural member, can replace aluminum alloy and other metal thin-wall parts, and achieves the effects of quality reduction and energy conservation. However, due to crystal structure defects of magnesium and magnesium alloys themselves, such as: magnesium is in a close-packed hexagonal structure, the independent sliding system which can be started is less, deformation is difficult to occur, and the room-temperature mechanical property is poor; in addition, magnesium belongs to active metal, and is easy to be oxidized by chemical reaction and has poor corrosion resistance, so that popularization and application of magnesium and magnesium alloy are greatly limited. Therefore, the application range of the magnesium alloy material can be widened only when the magnesium alloy material with good comprehensive mechanical property is produced and processed.
According to the current research situation, in order to improve the comprehensive mechanical properties of magnesium alloy, two approaches of alloying and grain refinement are mainly adopted. Alloying refers to adding one or more elements through smelting on the basis of common magnesium alloy so as to improve the strength and hardness of the magnesium alloy. However, the alloying smelting process requires adding alloy elements or rare earth elements, so that the cost is high. The severe plastic deformation is a main mode of grain refinement, and can overcome the defects of the traditional processing method, so that the grain size of the material is refined to submicron or even nanometer, excellent comprehensive mechanical properties are obtained, and the common severe plastic deformation mainly comprises: equal channel angular extrusion, high pressure twisting, and cumulative rolling. The violent plastic deformation methods are characterized in that equal channel angular extrusion is the most widely applied method at present, the shape and the size of a sample before and after extrusion are not changed, and the large plastic deformation can be accumulated by repeated extrusion deformation for many times, but the single extrusion deformation is small; high pressure torquing can produce sheet samples with smaller grain sizes, but with small sample sizes and non-uniform texture. In summary, many severe plastic deformation methods have a number of technical problems and disadvantages. Therefore, the invention discloses a device and a method for effectively weakening deformation texture and refining grains of magnesium alloy, which are very important for expanding the application range of the magnesium alloy.
Disclosure of Invention
The invention aims at providing a device and a method for preparing a fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion compounding, aiming at the background art, by the device and the processing method, magnesium alloy pipe blanks enter a deformation extrusion channel at a feed inlet, the inner wall and the outer wall of the pipe are respectively subjected to radial friction force from an inner cylindrical roller and an outer cylindrical roller, the magnesium alloy pipe is unevenly deformed along the radial direction under the action of the radial friction force, and the c-axis of the magnesium alloy is deflected along the radial force direction, so that severe plastic deformation occurs. Thereby realizing weakening texture and grain refinement, improving the room temperature mechanical property of the magnesium alloy pipe and expanding the application range of the magnesium alloy pipe.
The invention is realized by the following technical scheme: a device for preparing fine-grain magnesium alloy pipes by polygonal reverse rolling and twisting extrusion compounding comprises a power device, a reciprocating extrusion device, a differential rotary extrusion device, a horizontal extruder, an extrusion die and a bracket;
the reciprocating extrusion device comprises a left pressure motor and a right pressure motor which are respectively positioned at the left side and the right side of the horizontal extruder, the left pressure motor is connected with a left extrusion telescopic cavity through a left pressure motor conveying belt, the right pressure motor is connected with a right extrusion telescopic cavity through a right pressure motor conveying belt, the left extrusion telescopic cavity and the right extrusion telescopic cavity are respectively provided with a left extrusion telescopic cavity connecting rod and a right extrusion telescopic cavity connecting rod which are oppositely arranged, and the left extrusion telescopic cavity connecting rod and the right extrusion telescopic cavity connecting rod are respectively connected with a left extrusion compression ring and a right extrusion compression ring;
The extrusion die comprises a left fixed extrusion male die, a fixed extrusion female die and a right fixed extrusion male die which are fixedly arranged between the left fixed bracket and the right fixed bracket; a cavity is formed in the fixed extrusion female die, and the left fixed extrusion male die and the right fixed extrusion male die are respectively and fixedly arranged at the left side and the right side of the cavity of the fixed extrusion female die; annular cavities are formed between the periphery of the left fixed extrusion male die and the inner wall of the fixed extrusion female die, and between the periphery of the right fixed extrusion male die and the inner wall of the fixed extrusion female die, annular openings are formed in positions, corresponding to the annular cavities, on the left fixed support and the right fixed support, and the left extrusion telescopic compression ring and the right extrusion telescopic compression ring can respectively extend into the two annular cavities from the annular openings; the periphery of the fixed extrusion female die is sleeved with a heating sleeve;
the differential rotary extrusion device comprises an upper outer rotary extrusion cylinder, a lower outer rotary extrusion cylinder, an inner rotary extrusion cylinder, upper and lower outer rotary extrusion cylinder transmission shafts, a left inner rotary extrusion cylinder transmission shaft and a right inner rotary extrusion cylinder transmission shaft; the upper rotating extrusion cylinder and the lower rotating extrusion cylinder have the same structure, the external outline of the cylinder is of an unequal diameter structure, and the cylinder is arranged up and down and is opposite in head-tail orientation during installation; the upper outer rotating extrusion cylinder and the lower outer rotating extrusion cylinder are respectively supported between the left fixed bracket and the right fixed bracket through upper outer rotating extrusion cylinder transmission shafts and positioned in a cavity between the left fixed extrusion male die and the right fixed extrusion male die, and a space is reserved between the upper outer rotating extrusion cylinder and the lower outer rotating extrusion cylinder; the left fixed extrusion punch and the left fixed extrusion round table are internally provided with an axial cavity and are rotatably provided with a left internal rotation extrusion round table transmission shaft, the right fixed extrusion punch and the right fixed extrusion round table are internally provided with an axial cavity and are rotatably provided with a right internal rotation extrusion round table transmission shaft; the left and right ends of the inner rotary extrusion cylinder respectively extend into the shaft cavities of the left and right fixed extrusion round tables and are supported by bearings arranged in the left and right fixed extrusion round tables, hemispherical gears are connected to the left and right ends of the inner rotary extrusion cylinder after penetrating through the bearings, and hemispherical gears meshed with the left and right ends of the inner rotary extrusion cylinder are respectively arranged at the front ends of transmission shafts of the left and right inner rotary extrusion cylinders; the upper outer rotary extrusion cylinder and the lower outer rotary extrusion cylinder are in clearance fit with the inner wall of the fixed extrusion die; the outer diameters of the left fixed extrusion round table and the right fixed extrusion round table are of unequal diameter structures, the inner rotary extrusion cylinder is axially and obliquely arranged, the outer walls of the inner rotary extrusion cylinder deviate from the horizontal plane, and the angle of deviation of the outer walls of the upper outer rotary extrusion cylinder, the lower outer rotary extrusion cylinder and the corresponding parts of the inner rotary extrusion cylinder from the horizontal plane is larger than that of the outer walls of the inner rotary extrusion cylinder from the horizontal plane; the differential rotary extrusion channel is formed between the inner rotary extrusion cylinder and the outer walls of the upper outer rotary extrusion cylinder, the lower outer rotary extrusion cylinder and the inner walls of the fixed extrusion die, a left unequal diameter channel for communicating the left annular cavity with the differential rotary extrusion channel is formed between the outer wall of the left fixed extrusion circular table and the outer walls of the upper outer rotary extrusion cylinder, the lower outer rotary extrusion circular table and the inner walls of the fixed extrusion die, and a right unequal diameter channel for communicating the right annular cavity with the differential rotary extrusion channel is formed between the outer wall of the right fixed extrusion circular table and the outer walls of the upper outer rotary extrusion cylinder, the lower outer rotary extrusion cylinder and the inner walls of the fixed extrusion die; the left unequal diameter channel and the left annular cavity form a left extrusion channel, and the right unequal diameter channel and the right annular cavity form a right extrusion channel; the left extrusion channel, the differential rotation extrusion channel and the right extrusion channel jointly form a reciprocating rotation differential extrusion channel, and the diameters of two sides of the internal rotation extrusion cylinder are smaller than the diameter of the middle part;
The power device comprises a first outer cylinder motor, a second outer cylinder motor and an inner cylinder motor positioned in the center of an extrusion telescopic cavity, wherein one ends of an upper outer rotary extrusion cylinder transmission shaft and a lower outer rotary extrusion cylinder transmission shaft extend out of the support and are respectively connected with the first outer cylinder motor and the second outer cylinder motor, and an inner rotary extrusion cylinder transmission shaft extends out of the support and a hollow extrusion telescopic cavity connecting rod and is connected with the inner cylinder motor.
The inner rotating extrusion cylinder and the outer rotating extrusion cylinder are driven by the power device to drive the transmission shaft to rotate in opposite directions, so that the magnesium alloy pipe in the cavity is subjected to radial shearing force and is subjected to shearing deformation.
The outer wall of the outer rotary extrusion cylinder deviates from the horizontal plane by an angle larger than that of the inner rotary extrusion cylinder, so that the thickness of the differential rotary extrusion channel is changed and becomes thinner gradually.
The reciprocating rotary differential extrusion channel comprises a left extrusion channel formed by a left feeding area, a fixed extrusion male die and a fixed extrusion female die, a differential rotary extrusion channel formed by an outer rotary extrusion cylinder and an inner rotary extrusion cylinder, and a right extrusion channel formed by the fixed extrusion male die and the fixed extrusion female die from left to right in sequence. The magnesium alloy blank is pushed by the left and right extrusion press rings to reciprocate, the pipe diameter of the magnesium alloy pipe is continuously changed in the reciprocating motion process, and the thickness of the magnesium alloy pipe is reduced.
Further, the materials of the fixed extrusion female die, the left fixed extrusion male die, the right fixed extrusion male die, the left fixed extrusion round table, the right fixed extrusion round table, the upper outer rotary extrusion cylinder, the lower outer rotary extrusion cylinder and the inner rotary extrusion cylinder are all 4Cr5MoSiV1 hot work die steel; the surface roughness of the fixed extrusion female die, the left fixed extrusion male die and the right fixed extrusion male die is Ra0.08-0.16 mu m, the surface roughness of the inner rotary extrusion cylinder is Ra0.16-0.4 mu m, and the surface roughness of the upper and lower outer rotary extrusion cylinders is Ra0.4-0.8 mu m. The surface roughness of the magnesium alloy pipe forms asymmetric distribution with the roughness difference between the inner rotary extrusion cylinder and the outer rotary extrusion cylinder, so that the difference between the extrusion process and the friction force generated by the inner wall and the outer wall of the pipe blank is formed, the differential flow difference of the blank is further promoted to generate shearing deformation, shearing extrusion deformation is generated, the c axis of the crystal grain of the magnesium alloy pipe deflects along the radial direction, the basal plane texture effect of the magnesium alloy pipe is weakened, and the mechanical property of the magnesium alloy is improved.
A method for preparing a fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion compounding comprises the following steps:
s1, magnesium alloy blank pretreatment:
s1-1, processing a magnesium alloy blank into a magnesium alloy pipe, polishing the surface of the 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 inner surface and the outer surface of the magnesium alloy pipe are 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 a cleaning tank on an ultrasonic cleaning machine to ultrasonically clean the magnesium alloy pipe for 60min, taking out the magnesium alloy pipe material 36, 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 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 350-450 ℃, and after the heating furnace temperature reaches the set temperature, placing the magnesium alloy pipe into the heating furnace, and preserving heat for 12-48 hours;
s3, lubricating, assembling and preheating the differential rotary extrusion device:
s3-1, lubrication: coating graphite oil solution on the surfaces of the transmission shaft of the outer rotary extrusion cylinder, the contact part of the hemispherical gears, the inner rotary extrusion cylinder, the upper outer rotary extrusion cylinder, the outer surface of the lower outer rotary extrusion cylinder, the left extrusion telescopic cavity connecting rod, the right extrusion telescopic cavity connecting rod and the inner surface of the reciprocating differential rotary extrusion channel;
s3-2, assembling:
the horizontal extruder is provided with a left fixed bracket and a right fixed bracket, an upper outer rotating extrusion cylinder and a lower outer rotating extrusion cylinder are assembled with a fixed extrusion die, the upper outer rotating extrusion cylinder and the lower outer rotating extrusion cylinder are arranged in the fixed extrusion die, and the outer rotating extrusion cylinder is in clearance fit with the inner wall of the fixed extrusion die; the inner rotary extrusion cylinder is assembled with the left and right fixed extrusion convex dies after being connected with the left and right inner rotary extrusion cylinder transmission shafts through hemispherical gears, and the inner rotary extrusion cylinder is tightly connected with the left and right inner rotary extrusion cylinder transmission shafts in the left and right fixed extrusion convex dies; the left fixed extrusion male die and the right fixed extrusion female die are assembled between the left fixed bracket and the right fixed bracket and are tightly connected; connecting the installed upper, lower and outer rotary extrusion cylinder transmission shafts and the inner rotary extrusion cylinder transmission shaft with a power device; the left extrusion press ring and the right extrusion press ring are respectively connected with the left extrusion telescopic cavity and the right extrusion telescopic cavity, and the left extrusion press ring and the right extrusion press ring are matched with the left extrusion channel and the right extrusion channel;
S3-3, preheating: controlling the temperature of the heating sleeve to be 300-500 ℃, and preserving heat for 2-4 hours after the temperature reaches the set temperature for later use;
s4, rotary differential extrusion forming: the fixed extrusion female die, the left fixed extrusion male die, the right fixed extrusion male die, the upper outer rotary extrusion cylinder, the lower outer rotary extrusion cylinder and the inner extrusion cylinder form a reciprocating rotary differential extrusion channel; the reciprocating rotary differential extrusion channel comprises a left extrusion channel, a rotary differential extrusion channel and a right extrusion channel;
s4-1, placing a magnesium alloy pipe at a feed inlet of a left extrusion channel, fixing a left extrusion press ring and a right extrusion press ring, and starting a power device to enable an upper outer rotary extrusion cylinder, a lower outer rotary extrusion cylinder and an inner rotary extrusion cylinder to rotate in the opposite direction under the drive of a transmission shaft; starting a left pressure motor, sequentially passing through a left extrusion channel, a differential rotary extrusion channel and a right extrusion channel by the magnesium alloy pipe under the action of a left extrusion compression ring, wherein the included angles between the channel walls at two sides of the differential rotary extrusion channel and the horizontal direction are different, the extrusion channel is gradually thinned, the diameters at two sides of the inner rotary extrusion cylinder are smaller than the diameter of the middle part, and the diameter of the magnesium alloy pipe is firstly enlarged and then reduced after entering the extrusion channel to restore the diameter of the original pipe; in the rotating differential extrusion channel part, the rotating extrusion of the magnesium alloy pipe is started under the drive of friction force, and as the friction coefficients of the outer walls of the upper rotating extrusion cylinder, the lower rotating extrusion cylinder and the inner rotating extrusion cylinder are different, the inner wall and the outer wall are subjected to opposite radial friction forces with different magnitudes when the magnesium alloy pipe passes through the differential rotating extrusion channel, and the shearing deformation occurs; when the magnesium alloy pipe finishes left extrusion, after the magnesium alloy pipe reaches the right extrusion channel, the left pressure motor is closed, the right pressure motor is opened, under the action of the right extrusion press ring, the magnesium alloy pipe moves leftwards and passes through the differential rotation extrusion channel again, and after a few reciprocating periods, the right pressure motor and the right extrusion press ring 29 are disassembled, and the fine-grain magnesium alloy pipe is returned at the material returning opening;
S4-2, taking out the magnesium alloy pipe manufactured in the step S4-1, 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 fine-grain weak texture magnesium alloy pipe which can be directly put into use.
Compared with the prior art, the invention has the beneficial effects that:
1. the differential rotary extrusion channel deflects the C axis of the magnesium alloy, so that the basal plane texture of the magnesium alloy is effectively weakened, grains are refined, and the mechanical property of the magnesium alloy is improved;
2. the thickness of the extrusion channel tends to be reduced, the pipe is subjected to pressure between the extrusion channel walls which are gradually thinned after entering from the feeding hole, and meanwhile, under the action of the internal and external rotary extrusion cylinders, the pipe is subjected to the action of shearing force along the radial direction, and the shearing force can be controlled by adjusting the friction coefficient of the outer wall of the extrusion cylinder. The weakening effect of the grain texture of the magnesium alloy bar is more obvious.
Drawings
FIG. 1 is a state diagram of reciprocating differential extrusion processing of fine grain and weak texture magnesium alloy tubing in accordance with the present invention;
FIG. 2 is a schematic cross-sectional view of an extrusion channel;
FIG. 3 is a schematic outline view of the corresponding parts of the fixed extrusion die and the outer rotary extrusion cylinder;
FIG. 4 is a top view of the junction of the inner rotating extrusion cylinder and the drive shaft;
FIG. 5 is a cross-sectional view of the junction of the rotating extrusion cylinder and the drive shaft;
the list of reference numerals shown in the figures is as follows:
1-pilot lamp, 2-heating jacket switch, 3-power switch, 4-left extrusion telescopic ring switch, 5-left extrusion telescopic ring switch, 6-horizontal extruder base, 7-display screen, 8-horizontal extruder, 9-left connection wire, 10-left pressure motor base, 11-left pressure motor, 12-left pressure motor drive belt, 13-left internal rotation extrusion cylinder drive shaft, 14-left extrusion telescopic cavity, 15-left extrusion telescopic cavity link, 16-left fixed extrusion punch, 17-left extrusion press ring, 18-left extrusion channel, 19-left fixed support, 20-heating jacket, 21-upper external rotation extrusion cylinder drive shaft, 22-left fixed extrusion round table, 23-upper external rotation extrusion cylinder, 24-fixed extrusion die, 25-internal rotation extrusion cylinder, 26-right fixed extrusion round table, 27-right extrusion channel, 28-right fixed support, 29-right extrusion telescopic cavity link, 30-right extrusion telescopic cavity link, 31-first outer cylinder motor, 32-right extrusion telescopic cavity, 33-right internal rotation extrusion cylinder drive shaft, 34-right fixed extrusion motor, 35-right extrusion cylinder drive shaft, 35-lower rotation extrusion cylinder drive shaft, 36-outer rotation extrusion cylinder drive shaft, 22-left external rotation extrusion cylinder drive shaft, 27-right rotation extrusion cylinder, 25-right rotation extrusion cylinder drive shaft, 40-outer rotation guide wire, 40-outer rotation spherical drive shaft, 40-outer rotation alloy drive shaft, 40-outer rotation rotary extrusion cylinder, 40-outer rotation drive shaft, 40-outer rotation spherical drive shaft, 40-outer rotation extrusion cylinder drive shaft, and 40-outer rotation extrusion rotary extrusion cylinder drive shaft, and electric motor.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples.
A device for preparing fine-grain magnesium alloy pipes by polygonal reverse rolling and twisting extrusion composite comprises a power device, a reciprocating extrusion device, a differential rotary extrusion device, a horizontal extruder 8, an extrusion die and a bracket;
the reciprocating extrusion device comprises a left pressure motor 11 and a right pressure motor 38 which are respectively positioned at the left side and the right side of the horizontal extruder 8, the left pressure motor 11 is connected with a left extrusion telescopic cavity 14 through a left pressure motor conveying belt 12, the right pressure motor 38 is connected with a right extrusion telescopic cavity 32 through a right pressure motor conveying belt 46, the left extrusion telescopic cavity and the right extrusion telescopic cavity are respectively provided with a left extrusion telescopic cavity connecting rod 15 and a right extrusion telescopic cavity connecting rod 30 which are oppositely arranged, and the left extrusion telescopic cavity connecting rod 15 and the right extrusion telescopic cavity connecting rod 30 are respectively connected with a left extrusion compression ring 17 and a right extrusion compression ring 29;
the bracket comprises a left fixed bracket 19 and a right fixed bracket 28 which are arranged above the horizontal extruder 8, and the extrusion die comprises a left fixed extrusion male die 16, a fixed extrusion female die 24 and a right fixed extrusion male die 34 which are fixedly arranged between the left fixed bracket and the right fixed bracket; the inside of the fixed extrusion die 24 is provided with a cavity, and the left fixed extrusion punch 16 and the right fixed extrusion punch 34 are respectively and fixedly arranged at the left side and the right side of the cavity of the fixed extrusion die 24; annular cavities are formed between the periphery of the left fixed extrusion male die 16 and the inner wall of the fixed extrusion female die 24 and between the periphery of the right fixed extrusion male die 34 and the inner wall of the fixed extrusion female die 24, annular openings are formed in positions corresponding to the annular cavities on the left and right fixed brackets, and the left extrusion press ring 17 and the right extrusion press ring 29 can extend into the two annular cavities respectively from the annular openings; the periphery of the fixed extrusion female die 24 is sleeved with a heating sleeve 20;
The differential rotary extrusion device comprises an upper outer rotary extrusion cylinder 23, a lower outer rotary extrusion cylinder 39, an inner rotary extrusion cylinder 25, upper and lower outer rotary extrusion cylinder transmission shafts 21, 37, a left inner rotary extrusion cylinder transmission shaft 13 and a right inner rotary extrusion cylinder transmission shaft 33; the upper rotating extrusion cylinder and the lower rotating extrusion cylinder have the same structure, the external outline of the cylinder is of an unequal diameter structure, and the cylinder is arranged up and down and is opposite in head-tail orientation during installation; the upper outer rotary extrusion cylinder and the lower outer rotary extrusion cylinder are respectively supported between the left fixed support and the right fixed support through an outer rotary extrusion cylinder transmission shaft and positioned in a cavity between the left fixed extrusion male die and the right fixed extrusion male die, and a space is reserved between the upper outer rotary extrusion cylinder and the lower outer rotary extrusion cylinder; the two outer rotary extrusion cylinder transmission shafts are respectively positioned above and below the left fixed extrusion convex mould and the right fixed extrusion convex mould, the right side of the left fixed extrusion convex mould 16 extends out of the left fixed extrusion round platform 22 and stretches into the space between the left sides of the upper outer rotary extrusion cylinder and the lower outer rotary extrusion cylinder, the left side of the right fixed extrusion convex mould 34 extends out of the right fixed extrusion round platform 26 and stretches into the space between the right sides of the upper outer rotary extrusion cylinder and the lower outer rotary extrusion cylinder, an axial cavity is formed in the left fixed extrusion convex mould 16 and the left fixed extrusion round platform 22, a left inner rotary extrusion cylinder transmission shaft 13 is rotatably arranged in the left fixed extrusion convex mould 34 and the right fixed extrusion round platform 26, an axial cavity is formed in the right fixed extrusion round platform 26, and a right inner rotary extrusion cylinder transmission shaft 33 is rotatably arranged in the right fixed extrusion round platform; the inner rotary extrusion cylinder 25 is positioned in the middle of the interval between the upper rotary extrusion cylinder and the lower rotary extrusion cylinder, the left end and the right end of the inner rotary extrusion cylinder 25 respectively extend into the shaft cavities of the left fixed extrusion round table and the right fixed extrusion round table and are supported by bearings arranged in the left fixed extrusion round table and the right fixed extrusion round table, the left end and the right end of the inner rotary extrusion cylinder 25 pass through the bearings and are respectively connected with a hemispherical gear 35, and the front ends of transmission shafts of the left and the right rotary extrusion cylinders are respectively provided with hemispherical gears 35 meshed with the left end and the right end of the inner rotary extrusion cylinder 25; the upper and lower outer rotary extrusion cylinder outer contours and the inner rotary extrusion cylinder 25 are in clearance fit with the inner wall of the fixed extrusion die 24; the outer diameters of the left fixed extrusion round table and the right fixed extrusion round table are of unequal diameter structures, the inner rotary extrusion cylinder 25 is axially and obliquely arranged, the outer walls of the inner rotary extrusion cylinder 25 deviate from the horizontal plane, and the angle of deviation of the outer walls of the upper outer rotary extrusion cylinder, the lower outer rotary extrusion cylinder and the corresponding part of the inner rotary extrusion cylinder 25 from the horizontal plane is larger than that of the outer wall of the inner rotary extrusion cylinder 25 from the horizontal plane; the inner rotary extrusion cylinder 25 forms a differential rotary extrusion channel with the outer walls of the upper and lower outer rotary extrusion cylinders 23 and 39 and the inner wall of the fixed extrusion die 24, a left unequal diameter channel for communicating the left annular cavity with the differential rotary extrusion channel is formed between the outer wall of the left fixed extrusion round table 22 and the outer walls of the upper and lower outer rotary extrusion cylinders and between the inner wall of the fixed extrusion die 24, and a right unequal diameter channel for communicating the right annular cavity with the differential rotary extrusion channel is formed between the outer wall of the right fixed extrusion round table 26 and the outer walls of the upper and lower outer rotary extrusion cylinders and between the outer walls of the fixed extrusion die 24; the left unequal diameter channel and the left annular cavity form a left extrusion channel 18, and the right unequal diameter channel and the right annular cavity form a right extrusion channel 27; the left extrusion channel 18, the differential rotation extrusion channel and the right extrusion channel 27 jointly form a reciprocating rotation differential extrusion channel; the diameters of the two sides of the inner rotary extrusion cylinder 25 are smaller than the diameter of the middle part, and the friction coefficients of the upper and lower outer rotary extrusion cylinders 23 and 39 and the outer wall of the inner rotary extrusion cylinder 25 are different;
The power device comprises a first outer cylinder motor 31, a second outer cylinder motor and an inner cylinder motor positioned in the center of an extrusion telescopic cavity, wherein one ends of upper and lower outer rotary extrusion cylinder transmission shafts extend out of the support and are respectively connected with the first outer cylinder motor 31 and the second outer cylinder motor, and an inner rotary extrusion cylinder transmission shaft extends out of the support and a hollow extrusion telescopic cavity connecting rod and is connected with the inner cylinder motor.
The inside of the left extrusion telescopic cavity and the right extrusion telescopic cavity are connected with the left telescopic compression ring and the right telescopic compression ring so as to realize the reciprocating motion of the pipe in the deformation cavity.
The inner rotary extrusion cylinder 25 is driven to rotate by the transmission shaft of the inner rotary extrusion cylinder, the upper and lower outer rotary extrusion cylinders 23 and 39 are driven by the transmission device to rotate in opposite directions by the transmission shafts 21 and 37 of the upper and lower outer rotary extrusion cylinders, so that the magnesium alloy pipe 36 in the cavity is subjected to radial shearing force and is subjected to shearing deformation.
The outer walls of the upper and lower outer rotary extrusion cylinders 23, 39 deviate from the horizontal plane by an angle larger than that of the inner rotary extrusion cylinder 25, so that the thickness of the differential rotary extrusion channel is changed and becomes thinner gradually.
The upper and lower outer rotary extrusion cylinders 23, 39 are disposed in the fixed extrusion die 24, and the upper and lower outer rotary extrusion cylinders 23, 39 are in clearance engagement with the fixed extrusion die 24. The left and right internal rotation extrusion cylinder transmission shafts 13, 33 are arranged in the fixed extrusion male die 34, and the left and right internal rotation extrusion cylinder transmission shafts 13, 33 are respectively in clearance joint with the left and right fixed extrusion male dies 13, 34.
The reciprocating rotary differential extrusion channel comprises a left extrusion channel 18 formed by a left fixed extrusion male die 16 and a fixed extrusion female die 24, a differential rotary extrusion channel formed by upper and lower outer rotary extrusion cylinders 23 and 39 and an inner rotary extrusion cylinder 25, a right extrusion channel 27 formed by a right fixed extrusion male die 34 and a fixed extrusion female die 24, and a discharge region from left to right. The magnesium alloy pipe 36 reciprocates under the pushing of the left and right extrusion press rings 17 and 29, the pipe diameter of the magnesium alloy pipe 36 is continuously changed and the thickness is reduced in the reciprocating process.
Further, the outer diameter of the upper outer rotary extrusion cylinder 23 is divided into three parts from left to right, namely an expanding section, a diameter collecting section and a horizontal section, and the outer diameter of the lower outer rotary extrusion cylinder 39 is divided into three parts from right to left, namely an expanding section, a diameter collecting section and a horizontal section, which correspond to the horizontal section, the diameter collecting section and the expanding section of the upper outer rotary extrusion cylinder 23; the bottom of the left fixed extrusion round table 22 is consistent with the horizontal section trend of the lower outer rotary extrusion cylinder 39, and the top is consistent with the expanding section trend of the upper outer rotary extrusion cylinder 23; the bottom of the right fixed extrusion round table 26 is consistent with the expanding section of the lower outer rotary extrusion cylinder 39, and the top is consistent with the horizontal section of the upper outer rotary extrusion cylinder 23.
Further, the materials of the fixed extrusion die 24, the left fixed extrusion punch 16, the right fixed extrusion punch 34, the left fixed extrusion round table 22, the right fixed extrusion round table 26, the upper outer rotary extrusion cylinder 23, the lower outer rotary extrusion cylinder 39 and the inner rotary extrusion cylinder 25 are all 4Cr5MoSiV1 hot work die steel; the surface roughness of the fixed extrusion die 24, the left fixed extrusion punch 16 and the right fixed extrusion punch 34 is Ra0.08-0.16 mu m, the surface roughness of the inner rotary extrusion cylinder 25 is Ra0.16-0.4 mu m, and the surface roughness of the upper and lower outer rotary extrusion cylinders is Ra0.4-0.8 mu m.
The surface roughness of the magnesium alloy pipe 36 and the roughness difference of the inner rotary extrusion cylinder 25, the upper rotary extrusion cylinder 23, the lower rotary extrusion cylinder 39 form asymmetric distribution, so that the difference is formed between the extrusion process and the friction force generated by the inner wall and the outer wall of the pipe blank, and the differential flow differential shear deformation of the magnesium alloy pipe 36 is further promoted, and the shear extrusion deformation is generated to weaken the basal surface texture of the magnesium alloy pipe.
In the specific embodiment, materials and chemical reagents required in the preparation process are selected before the magnesium alloy with fine grain and weak texture is prepared by reciprocating torsional extrusion deformation: the preparation amounts of the magnesium alloy bar, the acetone, the absolute ethyl alcohol, the high-temperature graphite powder, the engine oil and the sand paper are as follows: in units of millimeter, milliliter, gram and tension
Magnesium alloy pipe: AZ31, phi 10mm multiplied by 100mm, and 3mm in thickness;
acetone: C3H6O,1000ml;
absolute ethyl alcohol: CH3CH2OH,2000ml;
high-temperature graphite powder: c,600g;
oil: SN 0W-40, 1500ml; sand paper: siC,800 meshes, 3 sheets; 2400 mesh, 4 sheets;
a method for preparing a fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion compounding comprises the following steps:
s1, magnesium alloy blank pretreatment:
s1-1, processing a magnesium alloy blank into a magnesium alloy pipe 36, polishing the surface of the magnesium alloy pipe 36 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 inner surface and the outer surface of the magnesium alloy pipe are 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 36 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 36, 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 36 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 350-450 ℃, and after the heating furnace temperature reaches the set temperature, placing the magnesium alloy pipe 36 into the heating furnace, and preserving the heat for 12-48 hours;
s3, lubricating, assembling and preheating the differential rotary extrusion device:
s3-1, lubrication: coating graphite oil solution on the surfaces of the transmission shafts 21 and 37 of the upper and lower outer rotary extrusion cylinders, the contact part of the hemispherical gears 35, the inner rotary extrusion cylinder 25, the upper outer rotary extrusion cylinder 23, the outer surface of the lower outer rotary extrusion cylinder 39, the left extrusion telescopic cavity connecting rod 15, the right extrusion telescopic cavity connecting rod 30 and the inner surface of the differential rotary extrusion channel;
s3-2, assembling:
the horizontal extruder 8 is provided with left and right fixed brackets 19 and 28, upper and lower outer rotary extrusion cylinders 23 and 39 are assembled with the fixed extrusion die 24, the upper and lower outer rotary extrusion cylinders 23 and 39 are arranged in the fixed extrusion die 24, and the outer rotary extrusion cylinders are in clearance fit with the inner wall of the fixed extrusion die 24; the inner rotary extrusion cylinder 25 is assembled with the left and right inner rotary extrusion cylinder transmission shafts 13 and 33 through hemispherical gears 35 and then is assembled with the left and right fixed extrusion male dies 16 and 34, and the inner rotary extrusion cylinder 25 and the left and right inner rotary extrusion cylinder transmission shafts 13 and 33 are arranged in the left and right fixed extrusion male dies 16 and 34 to be tightly connected; the left and right fixed extrusion male dies 16, 34 and the fixed extrusion female die 24 are assembled between the left fixed bracket 19 and the right fixed bracket 28 and are tightly connected; connecting the installed upper and lower outer rotary extrusion cylinder transmission shafts 21 with a power device; the left and right extrusion press rings 17, 29 are respectively connected with the left and right extrusion telescopic cavities 14, 32 and the left and right extrusion press rings 17, 29 are matched with the left and right extrusion channels 18, 27;
S3-3, preheating: controlling the temperature of the heating sleeve 20 to be 300-500 ℃, and preserving heat for 2-4 hours after the temperature reaches the set temperature for later use;
s4, rotary differential extrusion forming: the fixed extrusion die 24, the left and right fixed extrusion punches 16, 34, the upper and lower outer rotary extrusion cylinders 23, 39 and the inner rotary extrusion cylinder 25 form a reciprocating rotary differential extrusion channel; the reciprocating rotary differential extrusion channel comprises a left extrusion channel 18, a rotary differential extrusion channel and a right extrusion channel 27;
s4-1, placing a magnesium alloy pipe 36 at a feed port of the left extrusion channel 18, fixing the left extrusion press rings 17 and the right extrusion press rings 29, starting a power device, and enabling the upper outer rotary extrusion cylinders 23 and the lower outer rotary extrusion cylinders 39 and the inner rotary extrusion cylinder 25 to rotate in opposite directions under the drive of a transmission shaft; starting a left pressure motor 11, enabling a magnesium alloy pipe 36 to sequentially pass through a left extrusion channel 18, a differential rotary extrusion channel and a right extrusion channel 27 under the action of a left extrusion compression ring 17, wherein the included angles between the channel walls at two sides of the differential rotary extrusion channel and the horizontal direction are different, the extrusion channel is gradually thinned, the diameters at two sides of the inner rotary extrusion cylinder 25 are smaller than the diameter of the middle part, and the diameter of the magnesium alloy pipe 36 is firstly enlarged and then reduced after entering the extrusion channel to restore the diameter of the original pipe; in the rotating differential extrusion channel part, the magnesium alloy pipe 36 is driven by friction force to start rotating extrusion, and as the friction coefficients of the upper and lower outer rotating extrusion cylinders 23, 39 and the outer wall of the inner rotating extrusion cylinder 25 are different, when the magnesium alloy pipe 36 passes through the differential rotating extrusion channel, the inner wall and the outer wall are subjected to opposite radial friction forces with different magnitudes, and shearing deformation occurs; when the magnesium alloy pipe 36 completes left extrusion, after the magnesium alloy pipe reaches the right extrusion channel 27, the left pressure motor 11 is closed, the right pressure motor 38 is opened, under the action of the right extrusion press ring 29, the magnesium alloy pipe 36 moves leftwards and passes through the differential rotation extrusion channel again, and reciprocates in this way, after a few reciprocation periods, the right pressure motor 38 and the right extrusion press ring 29 are disassembled, and the fine-grain magnesium alloy pipe is returned at a material return port;
S4-2, taking out the magnesium alloy pipe 36 prepared in the step S4-1, 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 fine-grain weak texture magnesium alloy pipe capable of being directly put into use.
Further details are: in FIG. 2, the thickness t at the top inlet of the left unequal diameter channel 1 The method comprises the steps of carrying out a first treatment on the surface of the The thickness of the top inlet of the differential rotary extrusion channel is t 2 The thickness of the middle section at the top of the channel is t 3 The thickness of the outlet at the top of the channel is t 4 The method comprises the steps of carrying out a first treatment on the surface of the The thickness of the bottom inlet of the left unequal-diameter channel is t 5 The method comprises the steps of carrying out a first treatment on the surface of the The thickness of the bottom inlet of the differential rotary extrusion channel is t 6 The thickness of the middle section at the bottom of the channel is t 7 The thickness of the outlet at the bottom of the channel is t 8 The method comprises the steps of carrying out a first treatment on the surface of the The thicknesses have the following relation: t is t 1 ＞t 2 ＞t 3 ＞t 4 ，t 5 ＞t 6 ＞t 7 ＞t 8 The method comprises the steps of carrying out a first treatment on the surface of the The thickness of the area between the top and the bottom of the inlet of the left unequal diameter channel is between t 1 、t 5 Between the two, the thickness value of the area between the top and the bottom of the inlet of the differential rotary extrusion channel is t 2 、t 6 The thickness of the area between the top and the bottom of the middle section of the differential rotary extrusion channel is between t 3 、t 7 The thickness of the area between the top and the bottom of the outlet of the differential rotary extrusion channel is between t 4 、t 8 Between them; the thickness between the inlet and the outlet of the left unequal-diameter channel is equal to the thickness of the left unequal-diameter channel at the inlet and the outlet of the left unequal-diameter channel at the interval of t 1 、t 5 To t 2 、t 4 Is in a linear variation trend; the thickness from the inlet of the differential rotary extrusion channel to the middle section is equal to t 2 、t 6 To t 3 、t 7 The thickness from the middle section of the differential rotary extrusion channel to the outlet part is in a linear variation trend and is all according to the ratio of t 3 、t 7 To t 4 、t 8 Is in a linear variation trend;
the included angle between the outer wall of the upper outer rotary extrusion cylinder 23 at the top inlet of the left unequal diameter channel and the horizontal plane is theta 1 Here, the left fixed extrusion round table 22 forms an angle θ with the horizontal plane 2 The method comprises the steps of carrying out a first treatment on the surface of the The included angle between the outer wall of the upper outer rotary extrusion cylinder 23 at the top inlet of the differential rotary extrusion channel and the horizontal plane is theta 3 The included angle theta between the outer wall of the inner rotary extrusion cylinder 25 at the top inlet of the differential rotary extrusion channel and the horizontal plane is 4 The included angle between the outer wall of the upper outer rotary extrusion cylinder 23 at the middle section of the top of the differential rotary extrusion channel and the horizontal plane is theta 5 The included angle theta between the outer wall of the inner rotary extrusion cylinder 25 at the middle section of the top of the differential rotary extrusion channel and the horizontal plane is 6 The included angle between the outer wall of the left fixed extrusion round table 22 at the bottom of the left unequal-diameter channel and the horizontal plane is theta 7 The outer wall of the lower outer rotary extrusion cylinder 39 at the bottom of the left unequal diameter channel forms an included angle theta with the horizontal plane 8 The included angle between the outer wall of the lower outer rotary extrusion cylinder 39 at the bottom inlet of the differential rotary extrusion channel and the horizontal plane is theta 9 The included angle theta between the outer wall of the inner rotary extrusion cylinder 25 at the bottom inlet of the differential rotary extrusion channel and the horizontal plane is the same as the angle theta 10 The included angle theta between the outer wall of the lower outer rotary extrusion cylinder 39 at the middle section of the bottom of the differential rotary extrusion channel and the horizontal plane is 11 The included angle theta between the outer wall of the inner rotary extrusion cylinder 25 at the middle section of the bottom of the differential rotary extrusion channel and the horizontal plane is 12 The included angles have the following relation: θ 1 ＞θ 2 ，θ 4 ＞θ 3 ，θ 5 ＞θ 6 ，θ 8 ＞θ 7 ，θ 9 ＞θ 10 ，θ 11 ＞θ 12 。
The method for preparing the fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion compounding comprises the following steps of: (1) The power device, the reciprocating extrusion device, the differential rotary extrusion device, the horizontal extruder, the hemispherical turning transmission device (hemispherical gear), the base and the bracket are firmly installed, and the connection relation of the positions of the parts is correct and the parts are operated in sequence;
(2) Polishing the outer surface of an AZ31 magnesium alloy plate 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 surface is 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 plate and pipe blank, wherein the preset temperature is 400 ℃, and continuously placing the magnesium alloy plate and pipe blank into the heating furnace to keep the temperature for 3 hours when the preset temperature is reached;
(4) Heating the pipe, 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 inner surface and the outer surface of the magnesium alloy plate pipe for lubrication, wherein the diameter of the pipe is consistent with the diameter of the feed inlet. And (5) placing the pipe at the feeding hole regularly.
(6) The surface roughness of the fixed extrusion die 24, the left and right fixed extrusion punches 16, 34 is Ra0.08-0.16 μm, the surface roughness of the inner rotary extrusion cylinder 25 is Ra0.16-0.4 μm, and the surface roughness of the upper and lower outer rotary extrusion cylinders 23, 39 is Ra0.4-0.8 μm. The materials of the fixed extrusion female die, the fixed extrusion male die, the outer rotary extrusion cylinder and the inner rotary extrusion cylinder are all 4Cr5MoSiV1 hot work die steel.
(7) Starting a motor, setting the pressure to 400MPa, simultaneously starting a press machine and a motor at the left side and the right side, driving an inner rotary extrusion cylinder and an outer rotary extrusion cylinder to rotate by the motor, enabling a magnesium alloy pipe to pass through a deformation channel under the action of a compression ring, sequentially passing through a left extrusion channel, a differential rotary extrusion channel and a right extrusion channel, enabling the inner wall and the outer wall of the pipe in the differential rotary extrusion channel to bear shearing force in opposite directions, forcing the c-axis of the magnesium alloy blank to deflect, and refining grains. Further aggravate the plastic deformation of magnesium alloy blank, weaken the fine grain of texture, reciprocal extrusion is many times, finally through the bleeder zone, under fixed extrusion terrace die, fixed extrusion die, extrusion drum combined action, realize the course of working of magnesium alloy plate tubular product.
(8) Taking out the magnesium alloy pipe, 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 by using alcohol and drying by using a blower to blow. Conclusion: according to the method for preparing the fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion, the average grain size of the magnesium alloy pipe blank is greatly reduced compared with that of a conventional magnesium alloy, the basal plane texture is effectively weakened compared with that of an initial magnesium alloy pipe, and the mechanical property of the magnesium alloy is effectively improved. The materials and chemical reagents used are as follows: AZ31 magnesium alloy block-shaped billet with diameter d=50mm; 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: CH3CH2OH, 1200ml; acetone: C3H6O,800ml.
The principle of the invention for obtaining the fine-grain weak texture magnesium alloy through the steps is described in detail below with reference to the accompanying drawings: 1) FIG. 2 shows that the feed rate of the feed inlet is v and the angular velocity of the drive shaft of the outer rotary extrusion cylinder is ω 1， Internal rotation extrusion cylinder transmission shaft rotation angular velocity omega 2 The rotational angular velocity of the internal rotation extrusion cylinder is omega 3 ，ω 1 ≠ω 3 The included angle theta between the outer wall of the extrusion channel and the horizontal direction 1 ＞θ 2 ，θ 4 ＞θ 3 ，θ 5 ＞θ 6 ，θ 8 ＞θ 7 ，θ 9 ＞θ 10 ，θ 11 ＞θ 12 . Channel thickness t 1 ＞t 2 ＞t 3 ＞t 4 ，t 5 ＞t 6 ＞t 7 ＞t 8 。
2) Differential rotary extrusion process: starting a left extrusion press ring, extruding a magnesium alloy pipe blank which is placed in a die cavity of an extrusion die in advance, enabling the magnesium alloy pipe blank to enter an irregular shearing extrusion channel from the left extrusion channel under the action of the left extrusion press ring, enabling the diameter of the magnesium alloy pipe blank to gradually become larger along with the shape of an inner die, gradually become smaller and recover to an initial size, enabling the wall thickness to continuously change, enabling the blank flow rate to be different under the action of shearing force generated by differential rotation of an inner rotary extrusion cylinder in the middle and an upper outer rotary extrusion cylinder in the opposite direction, enabling the blank flow rate to be subjected to shearing deformation for multiple times, enabling grain structures to be thinned, and enabling grain c axes to be inclined and weakened in basal plane textures; when the left extrusion press ring completely enters the left extrusion channel of the extrusion die, the left extrusion telescopic press ring stops pushing; starting a right extrusion telescopic compression ring, extruding a magnesium alloy pipe blank arranged in a die cavity of an extrusion die, enabling the magnesium alloy pipe blank to enter an irregular differential rotary extrusion channel from a right extrusion channel under the action of the right extrusion compression ring, enabling the diameter of the magnesium alloy pipe blank to gradually become larger along with the shape of an inner die, gradually become smaller and restore to an initial state, enabling the wall thickness to continuously change, enabling the magnesium alloy pipe blank to repeatedly generate shearing deformation under the action of differential reverse extrusion of an inner extrusion cylinder and an outer extrusion cylinder, enabling a grain structure to be continuously thinned, and enabling a basal plane texture to be continuously weakened; and (5) circularly reciprocating to obtain the high-performance superfine crystal magnesium alloy pipe.
Through the principle, the magnesium alloy pipe blank is subjected to a large amount of shearing extrusion deformation, and the high-performance magnesium alloy pipe with the weak basal plane texture is obtained.
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 fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion is characterized by comprising a power device, a reciprocating extrusion device, a differential rotary extrusion device, a horizontal extruder (8), an extrusion die and a bracket;
the reciprocating extrusion device comprises a left pressure motor (11) and a right pressure motor (38) which are respectively positioned at the left side and the right side of the horizontal extruder (8), the left pressure motor (11) is connected with a left extrusion telescopic cavity (14) through a left pressure motor conveying belt (12), the right pressure motor (38) is connected with a right extrusion telescopic cavity (32) through a right pressure motor conveying belt (46), the left extrusion telescopic cavity and the right extrusion telescopic cavity are respectively provided with a left extrusion telescopic cavity connecting rod (15) and a right extrusion telescopic cavity connecting rod (30) which are oppositely arranged, and the left extrusion telescopic cavity connecting rod (15) and the right extrusion telescopic cavity connecting rod (30) are respectively connected with a left extrusion compression ring (17) and a right extrusion compression ring (29);
The support comprises a left fixed support (19) and a right fixed support (28) which are arranged above the horizontal extruder (8), and the extrusion die comprises a left fixed extrusion male die (16), a fixed extrusion female die (24) and a right fixed extrusion male die (34) which are fixedly arranged between the left fixed support and the right fixed support; a cavity is formed in the fixed extrusion female die (24), and the left fixed extrusion male die (16) and the right fixed extrusion male die (34) are respectively and fixedly arranged at the left side and the right side of the cavity of the fixed extrusion female die (24); annular cavities are formed between the periphery of the left fixed extrusion male die (16) and the inner wall of the fixed extrusion female die (24) and between the periphery of the right fixed extrusion male die (34) and the inner wall of the fixed extrusion female die (24), annular openings are formed in positions, corresponding to the annular cavities, on the left fixed support and the right fixed support, and the left extrusion compression ring (17) and the right extrusion compression ring (29) can extend into the two annular cavities respectively through the annular openings; the periphery of the fixed extrusion female die (24) is sleeved with a heating sleeve (20);
the differential rotary extrusion device comprises an upper outer rotary extrusion cylinder (23), a lower outer rotary extrusion cylinder (39), an inner rotary extrusion cylinder (25), upper and lower outer rotary extrusion cylinder transmission shafts, a left inner rotary extrusion cylinder transmission shaft (13) and a right inner rotary extrusion cylinder transmission shaft (33); the upper rotating extrusion cylinder and the lower rotating extrusion cylinder have the same structure, the external outline of the cylinder is of an unequal diameter structure, and the cylinder is arranged up and down and is opposite in head-tail orientation during installation; the upper outer rotating extrusion cylinder and the lower outer rotating extrusion cylinder are respectively supported between the left fixed bracket and the right fixed bracket through upper outer rotating extrusion cylinder transmission shafts and positioned in a cavity between the left fixed extrusion male die and the right fixed extrusion male die, and a space is reserved between the upper outer rotating extrusion cylinder and the lower outer rotating extrusion cylinder; the two outer rotary extrusion cylinder transmission shafts are respectively positioned above and below the left fixed extrusion convex mould and the right fixed extrusion convex mould, the right side of the left fixed extrusion convex mould (16) extends out of the left fixed extrusion round table (22) and stretches into the space between the left sides of the upper outer rotary extrusion cylinder and the lower outer rotary extrusion cylinder, the left side of the right fixed extrusion convex mould (34) extends out of the right fixed extrusion round table (26) and stretches into the space between the right sides of the upper outer rotary extrusion cylinder and the lower outer rotary extrusion cylinder, an axial cavity is formed in the left fixed extrusion convex mould (16) and the left fixed extrusion round table (22) and is rotatably provided with a left inner rotary extrusion cylinder transmission shaft (13), and the right fixed extrusion convex mould (34) and the right fixed extrusion round table (26) are internally provided with an axial cavity and are rotatably provided with a right inner rotary extrusion cylinder transmission shaft (33); the inner rotating extrusion cylinder (25) is positioned in the middle of the interval between the upper rotating extrusion cylinder and the lower rotating extrusion cylinder, the left end and the right end of the inner rotating extrusion cylinder (25) respectively extend into the shaft cavities of the left fixed extrusion round table and the right fixed extrusion round table and are supported by bearings arranged in the left fixed extrusion round table and the right fixed extrusion round table, the left end and the right end of the inner rotating extrusion cylinder (25) penetrate through the bearings and are respectively connected with a hemispherical gear (35), and the front ends of transmission shafts of the left rotating extrusion cylinder and the right rotating extrusion cylinder are respectively provided with hemispherical gears (35) meshed with the left end and the right end of the inner rotating extrusion cylinder (25); the upper outer rotary extrusion cylinder and the lower outer rotary extrusion cylinder are in clearance fit with the inner wall of the fixed extrusion die (24) by the inner rotary extrusion cylinder (25); the outer diameters of the left fixed extrusion round table and the right fixed extrusion round table are of unequal diameter structures, the inner rotary extrusion cylinder (25) is axially and obliquely arranged, the outer walls of the inner rotary extrusion cylinder and the corresponding parts of the upper outer rotary extrusion cylinder, the lower outer rotary extrusion cylinder and the inner rotary extrusion cylinder (25) deviate from the horizontal plane by an angle larger than the angle of the outer wall of the inner rotary extrusion cylinder (25) deviating from the horizontal plane; differential rotary extrusion channels are formed between the inner rotary extrusion cylinder (25) and the outer walls of the upper and lower outer rotary extrusion cylinders and between the inner walls of the fixed extrusion die (24), left unequal diameter channels for communicating a left annular cavity and the differential rotary extrusion channels are formed between the outer walls of the left fixed extrusion round table (22) and the outer walls of the upper and lower outer rotary extrusion cylinders and between the inner walls of the fixed extrusion die (24), and right unequal diameter channels for communicating a right annular cavity and the differential rotary extrusion channels are formed between the outer walls of the right fixed extrusion round table (26) and the outer walls of the upper and lower outer rotary extrusion cylinders and between the inner walls of the fixed extrusion die (24); the left unequal diameter channel and the left annular cavity form a left extrusion channel (18), and the right unequal diameter channel and the right annular cavity form a right extrusion channel (27); the left extrusion channel (18), the differential rotation extrusion channel and the right extrusion channel (27) jointly form a reciprocating rotation differential extrusion channel; the diameters of the two sides of the inner rotating extrusion cylinder (25) are smaller than the diameter of the middle part;
The power device comprises a first outer cylinder motor (31), a second outer cylinder motor and an inner cylinder motor positioned in the center of an extrusion telescopic cavity, wherein one ends of upper and lower outer rotary extrusion cylinder transmission shafts extend out of the support and are respectively connected with the first outer cylinder motor (31) and the second outer cylinder motor, and an inner rotary extrusion cylinder transmission shaft extends out of the support and a hollow extrusion telescopic cavity connecting rod and is connected with the inner cylinder motor.
2. The device for preparing the fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion compounding according to claim 1, wherein the outer diameter of the upper outer rotary extrusion cylinder (23) is divided into three parts from left to right, namely an expanding section, a diameter-collecting section and a horizontal section, the outer diameter of the lower outer rotary extrusion cylinder (39) is divided into three parts from right to left, namely an expanding section, a diameter-collecting section and a horizontal section, and the three parts correspond to the horizontal section, the diameter-collecting section and the expanding section of the upper outer rotary extrusion cylinder (23); the bottom of the left fixed extrusion round table (22) is consistent with the trend of the horizontal section of the lower outer rotary extrusion cylinder (39), and the top is consistent with the trend of the expanding section of the upper outer rotary extrusion cylinder (23); the bottom of the right fixed extrusion round table (26) is consistent with the trend of the expanding section of the lower outer rotary extrusion cylinder (39), and the top is consistent with the trend of the horizontal section of the upper outer rotary extrusion cylinder (23).
3. The device for preparing the fine-grain magnesium alloy pipe by multi-side reverse rolling and twisting extrusion compounding according to claim 2, wherein the thickness of the top inlet of the left unequal-diameter channel is t 1 The method comprises the steps of carrying out a first treatment on the surface of the The thickness of the top inlet of the differential rotary extrusion channel is t 2 The thickness of the middle section at the top of the channel is t 3 The thickness of the outlet at the top of the channel is t 4 The method comprises the steps of carrying out a first treatment on the surface of the The thickness of the bottom inlet of the left unequal-diameter channel is t 5 The method comprises the steps of carrying out a first treatment on the surface of the The thickness of the bottom inlet of the differential rotary extrusion channel is t 6 The thickness of the middle section at the bottom of the channel is t 7 The thickness of the outlet at the bottom of the channel is t 8 The method comprises the steps of carrying out a first treatment on the surface of the The thicknesses have the following relation: t is t 1 ＞t 2 ＞t 3 ＞t 4 ，t 5 ＞t 6 ＞t 7 ＞t 8 The method comprises the steps of carrying out a first treatment on the surface of the Between the top and the bottom of the inlet of the left unequal-diameter channelThe thickness of the region is between t 1 、t 5 Between the two, the thickness value of the area between the top and the bottom of the inlet of the differential rotary extrusion channel is t 2 、t 6 The thickness of the area between the top and the bottom of the middle section of the differential rotary extrusion channel is between t 3 、t 7 The thickness of the area between the top and the bottom of the outlet of the differential rotary extrusion channel is between t 4 、t 8 Between them; the thickness between the inlet and the outlet of the left unequal-diameter channel is equal to the thickness of the left unequal-diameter channel at the inlet and the outlet of the left unequal-diameter channel at the interval of t 1 、t 5 To t 2 、t 4 Is in a linear variation trend; the thickness from the inlet of the differential rotary extrusion channel to the middle section is equal to t 2 、t 6 To t 3 、t 7 The thickness from the middle section of the differential rotary extrusion channel to the outlet part is in a linear variation trend and is all according to the ratio of t 3 、t 7 To t 4 、t 8 Is in a linear variation trend;
the included angle between the outer wall of the upper outer rotary extrusion cylinder (23) at the top inlet of the left unequal-diameter channel and the horizontal plane is theta 1 The left fixed extrusion round table (22) has an included angle theta with the horizontal plane 2 The method comprises the steps of carrying out a first treatment on the surface of the The included angle between the outer wall of the upper outer rotary extrusion cylinder (23) at the top inlet of the differential rotary extrusion channel and the horizontal plane is theta 3 The included angle between the outer wall of the inner rotary extrusion cylinder (25) at the top inlet of the differential rotary extrusion channel and the horizontal plane is theta 4 The included angle between the outer wall of the upper outer rotary extrusion cylinder (23) at the middle section of the top of the differential rotary extrusion channel and the horizontal plane is theta 5 The included angle between the outer wall of the inner rotary extrusion cylinder (25) at the middle section of the top of the differential rotary extrusion channel and the horizontal plane is theta 6 The included angle between the outer wall of the left fixed extrusion round table (22) at the bottom of the left unequal-diameter channel and the horizontal plane is theta 7 The included angle between the outer wall of the lower outer rotary extrusion cylinder (39) at the bottom of the left unequal-diameter channel and the horizontal plane is theta 8 The included angle between the outer wall of the lower outer rotary extrusion cylinder (39) at the bottom inlet of the differential rotary extrusion channel and the horizontal plane is theta 9 The included angle between the outer wall of the inner rotary extrusion cylinder (25) at the bottom inlet of the differential rotary extrusion channel and the horizontal plane is theta 10 Lower outer rotary extrusion cylinder at middle section of bottom of differential rotary extrusion channel (39) The included angle between the outer wall and the horizontal plane is theta 11 The included angle between the outer wall of the inner rotary extrusion cylinder (25) at the middle section of the bottom of the differential rotary extrusion channel and the horizontal plane is theta 12 The included angles have the following relation: θ 1 ＞θ 2 ，θ 4 ＞θ 3 ，θ 5 ＞θ 6 ，θ 8 ＞θ 7 ，θ 9 ＞θ 10 ，θ 11 ＞θ 12 。
4. A device for preparing a fine-grain magnesium alloy pipe by multi-side reverse rolling and twisting extrusion compounding according to any one of claims 1-3, which is characterized in that the fixed extrusion die (24), the left fixed extrusion punch (16), the right fixed extrusion punch (34), the left fixed extrusion round table (22), the right fixed extrusion round table (26), the upper outer rotary extrusion cylinder (23), the lower outer rotary extrusion cylinder (39) and the inner rotary extrusion cylinder (25) are all made of 4Cr5MoSiV1 hot work die steel; the surface roughness of the fixed extrusion female die (24), the left fixed extrusion male die (16) and the right fixed extrusion male die (34) is Ra0.08-0.16 mu m, the surface roughness of the inner rotary extrusion cylinder (25) is Ra0.16-0.4 mu m, and the surface roughness of the upper and lower outer rotary extrusion cylinders is Ra0.4-0.8 mu m.
5. The method for preparing the fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion is characterized by comprising the following steps of:
s1, magnesium alloy blank pretreatment:
S1-1, processing a magnesium alloy blank into a magnesium alloy pipe (36), polishing the surface of the magnesium alloy pipe (36) 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 inner surface and the outer surface of the magnesium alloy pipe are 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 (36) 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 (36) for 60min, then taking out the magnesium alloy pipe (36) and 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 (36) 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 350-450 ℃, and after the heating furnace temperature reaches the set temperature, placing a magnesium alloy pipe (36) into the heating furnace, and preserving heat for 12-48 h;
s3, lubricating, assembling and preheating the differential rotary extrusion device:
s3-1, lubrication: coating graphite oil solution on the surfaces of a transmission shaft of an upper outer rotating extrusion cylinder, the surfaces of a transmission shaft of a lower outer rotating extrusion cylinder, the contact position of a hemispherical gear (35), an inner rotating extrusion cylinder (25), the outer surfaces of the upper outer rotating extrusion cylinder (23), the lower outer rotating extrusion cylinder (39), the surfaces of a left extrusion telescopic cavity connecting rod (15), the surfaces of a right extrusion telescopic cavity connecting rod (30) and the inner surfaces of differential rotating extrusion channels;
S3-2, assembling:
the horizontal extruder (8) is provided with a left fixed bracket and a right fixed bracket, an upper external rotating extrusion cylinder and a lower external rotating extrusion cylinder are assembled with a fixed extrusion female die (24), the upper external rotating extrusion cylinder and the lower external rotating extrusion cylinder are arranged in the fixed extrusion female die (24), and the external rotating extrusion cylinder is in clearance fit with the inner wall of the fixed extrusion female die (24); the inner rotating extrusion cylinder (25) is connected with a left inner rotating extrusion cylinder transmission shaft and a right inner rotating extrusion cylinder transmission shaft through a hemispherical gear (35) and then assembled with a left fixed extrusion male die and a right fixed extrusion male die, and the inner rotating extrusion cylinder (25) is tightly connected with the left inner rotating extrusion cylinder transmission shaft and the right inner rotating extrusion cylinder transmission shaft in the left fixed extrusion male die and the right fixed extrusion male die; the left fixed extrusion male die, the right fixed extrusion female die (24) are assembled between the left fixed bracket (19) and the right fixed bracket (28) and are tightly connected; connecting the installed upper, lower outer rotary extrusion cylinder transmission shafts with a power device; the left extrusion press ring and the right extrusion press ring are respectively connected with the left extrusion telescopic cavity and the right extrusion telescopic cavity, and the left extrusion press ring and the right extrusion press ring are matched with the left extrusion channel and the right extrusion channel;
s3-3, preheating: controlling the temperature of the heating sleeve (20) to be 300-500 ℃, and preserving heat for 2-4 hours after the temperature reaches the set temperature for later use;
S4, rotary differential extrusion forming: the fixed extrusion female die (24), the left and right fixed extrusion male dies, the upper and lower outer rotary extrusion cylinders and the inner rotary extrusion cylinder (25) form a reciprocating rotary differential extrusion channel; the reciprocating rotary differential extrusion channel comprises a left extrusion channel (18), a rotary differential extrusion channel and a right extrusion channel (27);
s4-1, placing a magnesium alloy pipe (36) at a feed inlet of a left extrusion channel (18), fixing a left extrusion compression ring and a right extrusion compression ring, starting a power device, and enabling an upper outer rotary extrusion cylinder, a lower outer rotary extrusion cylinder and an inner rotary extrusion cylinder (25) to rotate in opposite directions under the drive of a transmission shaft; starting a left pressure motor (11), enabling a magnesium alloy pipe (36) to sequentially pass through a left extrusion channel (18), a differential rotary extrusion channel and a right extrusion channel (27) under the action of a left extrusion compression ring (17), wherein the included angles between the channel walls at two sides of the differential rotary extrusion channel and the horizontal direction are different, the extrusion channel is gradually thinned, the diameters of two sides of an inner rotary extrusion cylinder (25) are smaller than the diameter of the middle part, and the diameter of the magnesium alloy pipe (36) is firstly enlarged and then reduced after entering the extrusion channel to restore the diameter of the original pipe; in the rotating differential extrusion channel part, the rotating extrusion of the magnesium alloy pipe (36) is started under the drive of friction force, and as the friction coefficients of the upper outer rotating extrusion cylinder, the lower outer rotating extrusion cylinder and the outer wall of the inner rotating extrusion cylinder (25) are different, when the magnesium alloy pipe (36) passes through the differential rotating extrusion channel, the inner wall and the outer wall are subjected to opposite radial friction forces with different magnitudes, and shearing deformation occurs; when the magnesium alloy pipe (36) completes left extrusion, after the magnesium alloy pipe reaches the right extrusion channel (27), the left pressure motor (11) is closed, the right pressure motor (38) is opened, under the action of the right extrusion press ring (29), the magnesium alloy pipe (36) moves leftwards and passes through the differential rotation extrusion channel again, and thus reciprocates, after a few reciprocation periods, the right pressure motor (38) and the right extrusion press ring (29) are disassembled, and the fine-grain magnesium alloy pipe is returned at the material returning opening;
S4-2, taking out the magnesium alloy pipe (36) prepared in the step S4-1, polishing the surface of the magnesium alloy pipe by sand paper, cleaning the magnesium alloy pipe by the cleaning liquid prepared in the step S1-2, and finally, secondarily cleaning by absolute ethyl alcohol, and drying by a blower to prepare the fine-grain weak texture magnesium alloy pipe which can be directly put into use.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311539093.0A CN117358767A (en) | 2023-11-17 | 2023-11-17 | Device and method for preparing fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311539093.0A CN117358767A (en) | 2023-11-17 | 2023-11-17 | Device and method for preparing fine-grain magnesium alloy pipe by polygonal reverse rolling and twisting extrusion |
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