CN107671159B - Restrictive molding die and grain refinement method for ultrasonic vibration-assisted demolding - Google Patents

Abstract

The invention discloses a restrictive die pressing die for ultrasonic vibration assisted demoulding and a grain refining method, relates to die processing and manufacturing and a using method thereof, and particularly relates to a die capable of enabling a workpiece to obtain large accumulated strain and a technological method for liking the grain size of a material. The restrictive mold press includes: the device comprises a mould frame, an ultrasonic auxiliary demoulding device and a mould cavity; the ultrasonic auxiliary demoulding device and the mould cavity are arranged in the mould frame together; the invention has the characteristics of novel structure, simple and convenient processing, simple and convenient operation, good workpiece adaptability, uniform strain distribution, convenient demoulding, small abrasion and the like, thereby belonging to a novel ultrasonic vibration assisted demoulding restrictive mould and a grain refining method which integrate economy and practicability.

Description

Restrictive molding die and grain refinement method for ultrasonic vibration-assisted demolding

technical field

The limited molding die and the grain refinement method for ultrasonic vibration-assisted demolding of the present invention relate to the processing and manufacturing of the die and a method for using the die, in particular to a die capable of obtaining a large cumulative strain on a workpiece, and a die that favors the grains of the material. size process.

Background technique

With the rapid development of the automobile, aerospace and nuclear energy industries, materials with superior mechanical and processing properties have been widely valued. Reducing the average grain size of metal or alloy materials to the ultrafine grain range (submicron and below) is an important method to improve its mechanical and processing properties. The material specific strength of ultrafine grained metals or alloy materials at room temperature It is greatly improved and has high strain rate superplastic properties, which is conducive to the precision machining and plastic microforming of materials. There are two ways to manufacture ultrafine-grained materials, the bottom-up method and the top-down method. The bottom-up method generates nanostructures by arranging atoms and stacking layer-by-layer, but this method can easily lead to porous structure defects and is difficult to be suitable for industrial manufacturing; another top-down method uses severe plastic deformation to make metal crystals. The characteristics of grain refinement are one of the effective ways to manufacture ultra-fine grained materials. At present, the common severe plastic deformation methods include restricted molding, equal-diameter angular extrusion, high-pressure torsion, cumulative stacking, multi-directional forging and repeated upsetting. Most of the methods are still small samples, which are difficult to apply to industrialization.

Confined molding is a severe plastic deformation method, which makes the metal material repeatedly deform in the mold without changing the original size, so as to obtain a large cumulative strain, which is suitable for the manufacture of ultra-fine grain thin plates. At present, ordinary trapezoidal slot dies are usually used in restrictive molding, and the tooth profile distribution is generally non-rotationally symmetrical. The deformation is uniform by reversing the workpiece, and the grains are refined by subsequent heat treatment. This method is usually suitable for rectangular thin plate workpieces, but has greater limitations for circular thin plate workpieces, and the cost and difficulty of mold processing are relatively high.

The traditional demoulding methods in the restrictive molding are mostly contact methods, which bring greater damage or deformation to the workpieces with low hardness and rigidity. The invention proposes a new non-contact demoulding method using ultrasonic vibration to assist workpiece demoulding. Under the action of ultrasonic energy, the "ultrasonic cavitation" phenomenon occurs in the liquid lubricant, which produces a large impact force in an instant; in addition, the ultrasonic vibration will also bring about a friction reduction effect, which will change the contact between the two objects from continuous contact without vibration. It becomes intermittent contact, which reduces friction and facilitates automatic demolding of the workpiece.

In view of the above problems in the prior art, it is very necessary to study and design a new type of ultrasonic vibration-assisted mold release limited molding die and grain refinement method, so as to overcome the existing problems in the prior art.

SUMMARY OF THE INVENTION

In view of the above-mentioned shortcomings such as poor adaptability of the existing restrictive molding die, uneven strain distribution, difficulty in mold processing, poor economy, and difficulty in demolding, the present invention researches and designs a limited molding die with ultrasonic vibration assisted demoulding, and a The processing method of grain refinement is suitable for the processing of rectangular and circular thin plate workpieces, and effectively solves the shortcomings of the existing molds.

The technical solution of the present invention is realized as follows:

The limiting molding die for ultrasonic vibration-assisted demoulding according to the present invention is characterized in that: the limiting molding die comprises: a mold base, an ultrasonic-assisted demolding device, and a mold cavity; the ultrasonic-assisted demolding device and the molding cavity are together installed in a mold base;

The mold base of the present invention includes: a mold handle, an upper fixing plate, an upper backing plate, a limit post, a guide post and a lower fixing plate; the die handle is connected with the upper fixing plate by bolts; the upper backing plate is fixed on the upper by means of bolts the lower part of the plate; the limit post is connected with the lower fixing plate through threads; the lower backing plate is placed in the groove on the upper part of the lower fixing plate; the upper fixing plate and the lower fixing plate are connected by the guide post;

The ultrasonic-assisted demoulding device of the present invention includes: an ultrasonic vibration generator, a limit block, and a rubber damping ring; the ultrasonic vibration generator is placed in the center hole of the upper part of the upper pad; the rubber damping ring is sleeved on the connection upper pad The bolts of the plate and the upper fixing plate are placed between the upper backing plate and the upper fixing plate; the limit block is fixed on the upper part of the upper backing plate by bolts;

The mold cavity of the present invention includes: a replaceable upper mold and a replaceable lower mold;

The replaceable upper die of the present invention is mounted on the lower part of the upper backing plate through bolts; the replaceable upper die includes three different groove types of concave die I, concave die II and concave die III; The end face is machined with a 45° trapezoidal tooth groove, and the ratio of the tooth height, the width of the tooth groove bottom and the distance between two adjacent grooves is 1:2:6; the concave die II is a flat die; the lower part of the concave die III is The end face is machined with 45° trapezoidal tooth grooves, and the ratio of tooth height, tooth groove bottom width and the spacing between adjacent two grooves is 1:1:3;

The replaceable lower die of the present invention is integrally connected with the lower backing plate and the lower fixing plate by means of bolts; the replaceable lower die includes punches I, punches II and punches III of three different groove types; the punches The die I has a convex model matched with the concave die I; the convex die II is a flat die; the convex die III has a convex model matched with the concave die III.

The ultrasonic vibration generator of the present invention converts a specific signal into ultrasonic mechanical vibration, the specific signal includes: current, voltage, magnetic field strength, and is converted into 20kHz mechanical vibration through the transducer, so that the lubricant cavitates, Reduce friction between workpiece and replaceable top touch.

Compared with the replaceable lower mold, the replaceable upper mold of the present invention has more contact area with the workpiece, so as to ensure that the workpiece is embedded in the replaceable upper mold after sufficient deformation. , so that the workpiece is automatically demolded under the action of gravity and ultrasonic vibration.

The grain refining method of the present invention is:

1) Assemble the mold cavity on the upper backing plate and the lower backing plate; choose the concave mold I and the punch I for the mold cavity, and evenly apply the liquid lubricant in the mold cavity;

2), put the workpiece into the mold cavity uniformly coated with liquid lubricant described in step 1); start the external pressure device to drive the mold base to press down the die I through the mold handle until the workpiece is fully deformed. The flat workpiece is processed into a deformed workpiece I, the shear strain in the deformation zone of the deformed workpiece I is ε, and no strain occurs in the undeformed zone;

3) Raise the die I through the external pressure device, and start the ultrasonic-assisted demoulding device to demould the workpiece;

4), replace the mold cavity, the mold cavity selects the concave mold II and the convex mold II; and evenly apply the liquid lubricant in the mold cavity;

5) Put the deformed workpiece I into the mold cavity replaced in step 3), and activate the external pressure device to drive the mold base to press down the die II through the mold handle (1) until the workpiece is flattened. Deformed workpiece I is processed into deformed workpiece II, the shear strain in the deformation zone of deformed workpiece II is 2ε, and no strain occurs in the undeformed zone;

6) Raise the die II through the external pressure device, and start the ultrasonic-assisted demoulding device to demould the workpiece;

7), replace the mold cavity, the mold cavity selects the concave mold III and the convex mold III; and evenly apply the liquid lubricant in the mold cavity;

8) Put the deformed workpiece II into the mold cavity for replacement in step 7); at this time, the undeformed part after processing in step 2) is in the deformation zone, and the part that has obtained 2ε shear strain is in the non-deformation zone, start The external pressure device drives the mold base to press down the die III through the die handle until the workpiece is fully deformed. In the above processing process, the workpiece is processed from the deformed workpiece II to the deformed workpiece III, and the shear strain in the deformation area of the deformed workpiece III is ε, which is not The deformation zone does not produce strain;

9) Raise the die III through the external pressure device, and start the ultrasonic auxiliary demolding device to demold the workpiece;

10), replace the cavity, the cavity chooses the concave die II and the punch II; and evenly apply the liquid lubricant in the cavity;

11), put the deformed workpiece III (8-4) into the mold cavity for replacement in step 10); start the external pressure device to drive the mold base to press the die II through the mold handle until the workpiece is flattened. During the above processing process The workpiece is processed from the deformed workpiece III to the deformed workpiece IV. The shear strain in the deformation zone of the deformed workpiece IV is 2ε, and no strain occurs in the undeformed zone. At this time, the entire workpiece obtains a uniformly distributed shear strain with a value of 2ε;

12), repeat steps 1)-11) until the workpiece obtains the ideal cumulative strain;

Since the workpiece of the present invention has different accumulated strains, it should be heat treated at different temperatures and times to obtain grain structures with different degrees of refinement.

The workpiece according to the present invention, which is a rectangular or circular thin plate, can obtain symmetrical and uniform deformation after being processed in the above steps 1)-11), and suffer less damage during demolding.

The advantages of the present invention are obvious, mainly manifested in:

Compared with the existing devices and technologies, the limited molding die and the grain refining method for ultrasonic-assisted demolding according to the present invention have the following advantages:

1. Through the redesign of the die groove, the processing cost of the die can be greatly reduced. The die can be processed not only into straight grooves, but also into rotary grooves, corresponding to the processing of rectangular and circular workpieces respectively; secondly, Compared with the existing mold, the mold of the present invention can make the workpiece obtain a more uniform strain distribution, so that the recrystallization distribution and the microstructure distribution of the workpiece are more uniform.

2. The demolding device uses the cavitation effect of ultrasonic vibration on the liquid lubricant and the friction reduction effect of ultrasonic vibration, so that the workpiece can be demolded by itself under the action of its own gravity, which minimizes the traditional demoulding process of the workpiece as much as possible. The damage received simplifies the complex demolding structure of the existing mold, reduces the mold manufacturing cost, and improves the processing efficiency.

3. The grain refinement method uses the ultrasonic vibration assisted demoulding limited molding die, which can accurately control the equivalent strain value of the processed workpiece by controlling the number of repeated processing; through the existing heat treatment process data , respectively, using different heat treatment temperatures and holding times to obtain the desired grain size accurately, thereby changing the mechanical and processing properties of the material to meet specific needs.

Poor adaptability, uneven strain distribution, difficult mold processing and poor economy, difficult demolding

The invention has the advantages of novel structure, simple processing, simple operation, good adaptability of the workpiece, uniform strain distribution, convenient demoulding, low wear and the like.

Description of drawings

The present invention has a total of accompanying drawings, wherein:

Accompanying drawing 1 is the structure schematic diagram of the present invention;

Accompanying drawing 2 is three kinds of concave and convex dies described in the embodiment of the present invention, and processing sequence;

Accompanying drawing 3 is the enlarged view of A part of accompanying drawing 2;

Accompanying drawing 4 is the enlarged view of B part of accompanying drawing 2;

5 is a schematic diagram of the structure and strain accumulation process of the workpiece of the present invention after processing in different working steps;

Accompanying drawing 6 is the C part enlarged view of accompanying drawing 5;

Accompanying drawing 7 is the enlarged view of D part of accompanying drawing 5;

FIG. 8 is a flow chart of the grain refining method according to the embodiment of the present invention.

In the picture: 1 Die handle 2 Ultrasonic vibration generator 3 Upper fixed plate 4 Limit block 5 Rubber shock absorbing ring 6 Upper die 6-1, Die Ⅰ 6-2, Die Ⅱ 6-3, Die Ⅲ 7 Upper backing plate 8 workpiece 8-1, flat workpiece 8-2, deformed workpiece Ⅰ 8-3, deformed workpiece Ⅱ 8-4, deformed workpiece Ⅲ 8-5, deformed workpiece Ⅳ 9 limit column 10 lower die 10-1, Punch I 10-2, Punch II 10-3, Punch III 11 Lower backing plate 12 Guide post 13 Lower fixed plate a, undeformed area b, shear deformation area, shear strain is εc, shear deformation area, The shear strain is 2ε.

Detailed ways

A specific embodiment of the present invention is shown in the accompanying drawings, a limited molding die for ultrasonic vibration-assisted demoulding, including: a mold base, an ultrasonic-assisted demolding device, and a mold cavity; the ultrasonic-assisted demolding device and the mold cavity are installed in the mold base together. ;

The mold base includes: a mold handle 1, an upper fixing plate 3, an upper backing plate 7, a limit post 9, a guide post 12 and a lower fixing plate 13; the die handle 1 is connected with the upper fixing plate 3 by bolts; the upper backing plate 7 is connected by bolts It is mounted on the lower part of the upper fixing plate 3; the limit post 9 is connected with the lower fixing plate 13 through threads; the lower backing plate 11 is placed in the groove on the upper part of the lower fixing plate 13; 12 connected;

The ultrasonic auxiliary demoulding device includes: an ultrasonic vibration generator 2, a limit block 4, and a rubber damping ring 5; the ultrasonic vibration generator 2 is placed in the central hole of the upper part of the upper backing plate 7; the rubber damping ring 5 is sleeved on the connection The backing plate 7 and the bolts of the upper fixing plate 3 are placed between the upper backing plate 7 and the upper fixing plate 3; the limit block 4 is fixed on the upper part of the upper backing plate 7 by bolts;

The mold cavity includes: replaceable upper mold 6 and replaceable lower mold 10;

The replaceable upper die 6 is mounted on the lower part of the upper backing plate 7 through bolts; the replaceable upper die 6 includes three different groove types of concave die I6-1, concave die II6-2 and concave die III6-3; The lower end face of the die I6-1 is machined with a 45° trapezoidal tooth slot, and the ratio of the tooth height, the width of the tooth slot bottom and the spacing between two adjacent slots is 1:2:6; the female die II6-2 is a flat die; The lower end face of the female die III6-3 is machined with a 45° trapezoidal tooth slot, and the ratio of the tooth height, the tooth slot bottom width and the distance between two adjacent slots is 1:1:3;

The replaceable lower die 10 is integrally connected with the lower backing plate 11 and the lower fixing plate 13 by bolts; the replaceable lower die 10 includes three different groove types of punches I10-1, punches II10-2 and punches III10-3 ; The punch I10-1 has a convex model that matches with the concave die I6-1; the punch II10-2 is a flat die; the punch III10-3 has a concave die III6-3 Matching raised models.

The ultrasonic vibration generator 2 converts a specific signal into ultrasonic mechanical vibration. The specific signal includes: current, voltage, and magnetic field strength, and is converted into 20kHz mechanical vibration through the transducer, so that the lubricant cavitates and reduces the workpiece and the possible vibration. Replace the friction on touch 6.

Compared with the replaceable lower mold 10, the replaceable upper mold 6 has more contact area with the workpiece, so as to ensure that the workpiece is embedded in the replaceable upper mold 6 after sufficient deformation. The workpiece is automatically demolded under the action of gravity and ultrasonic vibration.

A method for refining grains of a restricted molding die with ultrasonic vibration assisted demoulding: characterized in that the method for refining grains is:

1) Assemble the mold cavity on the upper backing plate 7 and the lower backing plate 11; for the mold cavity, select the concave mold I6-1 and the punch I10-1, and apply liquid lubricant evenly in the mold cavity;

2), put the workpiece 8 into the mold cavity uniformly coated with the liquid lubricant described in step 1); start the external pressure device to drive the mold base to press down the die I6-1 through the mold handle 1 until the workpiece is fully deformed, and the above processing is performed. In the process, the workpiece 8 is processed from the flat workpiece 8-1 into a deformed workpiece I8-2, the shear strain in the deformation area of the deformed workpiece I8-2 is ε, and no strain is generated in the undeformed area;

3) Raise the die I6-1 through the external pressure device, and start the ultrasonic-assisted demoulding device to demold the workpiece;

4), replace the mold cavity, the mold cavity selects the concave die II6-2 and the punch II10-2; and evenly apply the liquid lubricant in the mold cavity;

5) Put the deformed workpiece I8-2 into the mold cavity replaced in step 3), start the external pressure device through the mold handle (1) to drive the mold base to press down the female mold II6-2 until the workpiece is flattened, and then process the above-mentioned process. In the process, the workpiece 8 is processed from the deformed workpiece I8-2 to the deformed workpiece II8-3, the shear strain in the deformation zone of the deformed workpiece II8-3 is 2ε, and no strain is generated in the undeformed zone;

6) Raise the die II6-2 through the external pressure device, and start the ultrasonic-assisted demoulding device to demold the workpiece;

7), replace the cavity, the cavity chooses the concave die III6-3 and the punch III10-3; and evenly apply the liquid lubricant in the cavity;

8) Put the deformed workpiece II8-3 into the mold cavity for replacement in step 7); at this time, the undeformed part after step 2) is in the deformation zone, and the part that has obtained 2ε shear strain is in the non-deformation zone , start the external pressure device and drive the die base to press the die III6-3 through the die handle 1 until the workpiece is fully deformed. During the above processing process, the workpiece 8 is processed from the deformed workpiece II8-3 to the deformed workpiece III8-4. The shear strain of the deformed region of 4 is ε, and the undeformed region does not produce strain;

9) Raise the die III6-3 through the external pressure device, and start the ultrasonic-assisted demoulding device to demold the workpiece;

10), replace the cavity, the cavity selects the female die II 6-2 and the punch II 10-2; and evenly apply the liquid lubricant in the cavity;

11), put the deformed workpiece III8-4 into the mold cavity for replacement in step 10); start the external pressure device to drive the mold base to press down the die II6-2 through the mold handle 1 until the workpiece is flattened. During the above processing process Workpiece 8 is processed from deformed workpiece III8-4 to deformed workpiece IV8-5. The shear strain in the deformation zone of deformed workpiece IV8-5 is 2ε, and no strain occurs in the undeformed zone. At this time, the entire workpiece is uniformly distributed and the value is 2ε shear strain;

12), repeat steps 1)-11) until the workpiece 8 obtains the ideal cumulative strain;

Since the workpiece 8 has different accumulated strains, heat treatment at different temperatures and times should be performed to obtain grain structures with different degrees of refinement.

The workpiece 8 is a rectangular or circular thin plate, which can obtain symmetrical and uniform deformation after processing in the above steps 1)-11), and suffer less damage during the demolding process.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. The equivalent replacement or change of the solution and the concept of the present invention shall be included within the protection scope of the present invention.

Claims (1)

1. A restrictive molding die for ultrasonic vibration-assisted demolding, comprising: a die base and an ultrasonic-assisted demolding device; the die set comprises: a die handle (1), an upper fixing plate (3), an upper backing plate (7), The limit post (9), the guide post (12) and the lower fixing plate (13); the die handle (1) is connected with the upper fixing plate (3) by bolts; the upper backing plate (7) is mounted on the upper fixing plate ( 3); the limit post (9) is connected with the lower fixing plate (13) through threads; the lower backing plate (11) is placed in the groove on the upper part of the lower fixing plate (13); the upper fixing plate (3) is connected with the lower The fixing plate (13) is connected by a guide post (12); the ultrasonic auxiliary demolding device comprises: an ultrasonic vibration generator (2), a limit block (4), a rubber shock absorbing ring (5); an ultrasonic vibration generator (2) ) in the upper center hole of the upper backing plate (7); the rubber shock absorbing ring (5) is sleeved on the bolts connecting the upper backing plate (7) and the upper fixing plate (3), and is placed on the upper backing plate (7) ) and the upper fixing plate (3); the limit block (4) is fixed on the upper part of the upper backing plate (7) by bolts; the ultrasonic vibration generator (2) converts the specific signal into ultrasonic mechanical vibration, and the specific The signals include: current, voltage, and magnetic field strength, which are converted into 20 kHz mechanical vibration through the transducer, cavitating the lubricant and reducing the friction between the workpiece and the replaceable upper die (6); It is characterized in that: the restrictive molding die further comprises: a mold cavity composed of a replaceable upper mold (6) and a replaceable lower mold (10); The replaceable upper die (6) is mounted on the lower part of the upper backing plate (7) by means of bolts; the replaceable upper die (6) includes three types of concave die I (6-1) and concave die II ( 6-2) and concave die III (6-3); the lower end face of the concave die I (6-1) is machined with a 45° trapezoidal tooth groove, and the tooth height, the width of the tooth groove bottom and the distance between two adjacent grooves are processed. The ratio is 1:2:6; the concave die II (6-2) is a flat die; the lower end face of the concave die III (6-3) is machined with a 45° trapezoidal tooth groove, and the tooth height, The ratio of the bottom width of the tooth slot and the distance between two adjacent slots is 1:1:3; The replaceable lower die (10) is integrally connected with the lower backing plate (11) and the lower fixing plate (13) through bolts; the replaceable lower die (10) includes three punches I (10- 1), punch II (10-2) and punch III (10-3); the punch I (10-1) has a convex model matching the punch I (6-1); The punch II (10-2) is a flat die; the punch III (10-3) has a convex model matched with the punch III (6-3); Compared with the replaceable lower mold (10), the replaceable upper mold (6) has more contact area with the workpiece, so as to ensure that the workpiece is embedded in the replaceable upper mold (6) after being sufficiently deformed. , The workpiece is automatically demolded under the action of gravity and ultrasonic vibration through the ultrasonic-assisted demoulding device.

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