KR20120058256A - Apparatus and Method for Continuous Shear Forming - Google Patents

Abstract

PURPOSE: An apparatus and a method for load-reduced continuous shear forming are provided to extend the life span of a die by reducing a load applied to the die using ultrasonic vibration. CONSTITUTION: An apparatus for load-reduced continuous shear forming comprises a rolling roll(10), a die(30), and a die vibration transfer unit(50). The rolling roll applied a compressive force for shear deformation of a material. The die implements shear deformation of a material passing through the rolling roll. The die vibration transfer unit reduces a load applied to the die. The die comprises a channel(32) having a cross-over region enabling shear deformation. The die vibration transfer unit comprises a vibrator(58) which is associated with an ultrasonic generator to transfer ultrasonic vibration to the die.

Description

Load-reducing continuous shearing apparatus and method {Apparatus and Method for Continuous Shear Forming}

The present invention relates to an apparatus and method for continuous shearing that enables rigid processing of materials, in particular for continuous machining, and more particularly to enabling an increase in cumulative strain values, and to (continuously) continuous shearing without material reduction. While enabling, in particular, the present invention relates to a load reduction continuous shearing apparatus and method for transmitting (applying) ultrasonic vibrations to a die to implement a reduction in load applied to the die, thereby extending the life of the die.

The method of improving the strength of the material is to refine the final austenite grain size (hereinafter referred to as 'AGS') using the controlled rolling and / or controlled cooling of the material.

By the way, such AGS microstructure is mainly implemented in the hot rolling and rapid cooling process, the size of the rolling or rapid cooling equipment is significant, there is a problem that the rolling load increases due to low temperature rolling, but continuous Because of the process, the benefits of enabling mass production are provided.

On the other hand, another method of miniaturizing AGS without going through such a large-scale facility or process, is that nano-size (nano-size) by imparting shear strain at room temperature without complex thermal changes (ie, cooling process) In order to intentionally create a microstructure of the () and to increase the strength, for example, there is a severe plastic deformation (hereinafter referred to as 'SPD').

For example, one of the methods of such an SPD, although not shown in a separate drawing, generates a compressive force of a material by using a punch to impart material shear deformation in the die, thereby making a uniform channel angular compression molding. (Equal Channel Angular Pressing) (hereinafter referred to as 'ECAP').

Such an ECAP method is known to improve various mechanical properties such as strength increase due to tissue miniaturization during shearing, formation of specific tissues, and improvement of fatigue properties.

However, the known ECAP processing method has a problem that continuous processing is difficult, for example, although not shown in a separate drawing, because the use of a punch, the processing length is limited and the size of the material that can be processed is limited, additional processing Extraction of materials for processing is also difficult.

On the other hand, another conventional method for solving the difficulty of such continuous processing during ECAP processing is a technique disclosed in Patent Application No. 10-2010-0115292 filed by the applicant of the present application, by adding a rolling step to ECAP processing In addition, the material processing through shear deformation is realized, and in particular, continuous processing is possible.

For example, the shearing processing method (ECAP-Rolling) given rolling in the patent application is a problem in the existing ECAP processing by generating a compressive force through rolling, and recovering the reduction of material during rolling through a recovery mechanism This allows for continuous machining.

However, the shearing method with the rolling disclosed in the patent application may cause a problem that the wear of the die is accelerated,

For example, the known drawing process is uniformly exempted by passing through an axisymmetric die, but the rolling additive ECAP process (EACP-Rolling) is based on the ECAP process described above, so the material is processed asymmetrically, This results in a locally large contact pressure at the channel intersection where the internal channels of the die intersect.

Accordingly, the applicant of the present invention proposes the present invention based on the ECAP processing that implements the compressive force for the shear deformation of the material in the die by rolling, and solves the problem of die wear, which occurs during rolling additive ECAP processing, in particular. It became.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned conventional problems, and enables the increase of the cumulative strain value and enables (high speed) continuous processing without material reduction, in particular, by transmitting ultrasonic vibration to the die to the die. SUMMARY OF THE INVENTION An object of the present invention is to provide a load reducing continuous shearing apparatus and method for reducing the load applied to prolong the life of a die.

The present invention as a technical aspect for achieving the above object, the rolling roll provided to apply a compressive force for shear deformation of the material;

A die provided to shear deformation of the material subjected to the rolling roll; And,

Vibration transmission means of the die provided to reduce the load on the die;

It provides a load reduction continuous shearing device configured to include.

Preferably, the die includes a channel having an intersection to enable shear deformation, and the vibration transmitting means of the die includes a vibrator provided to transmit ultrasonic vibration to the die in association with the ultrasonic generator.

More preferably, the material rolling step of providing a compressive force for shear deformation of the material; And,

A material processing step in which the material is sheared at the die;

Including continuous processing,

Vibration transmission step of the die is carried out in at least the material processing step of the rolling step and the material processing step;

Provides a continuous shear processing method further comprises a.

In another aspect, the present invention, in the material rolling step, using the rolling roll of the ball roll or flat roll is inserted into the intersection of the die to the intersection of the die, while applying the compressive force to the inserted material, Deformation is made, in the material processing step, after the preceding deformation of the material, the shear deformation of the material is made at the channel intersection of the die during rolling, and sufficient contact with the die is made by the repulsive force of the material at the channel intersection, the initial cross-sectional area To recover.

Preferably, the vibration transmission step of the die is to transmit the ultrasonic vibration to the die through a vibrator disposed in close contact with the die.

More preferably, in the vibration transmission step of the die, the ultrasonic vibration is applied to the channel intersection of the die after the die filling of the material, the ultrasonic vibration is applied in the horizontal or vertical direction of the material traveling direction.

According to such a load-reducing continuous shearing apparatus and method of the present invention, in spite of the ECAP processing, it is possible to increase the cumulative strain value of the material by applying the compressive force during rolling, while enabling continuous processing through rolling It is.

Thus, the present invention allows for continuous (high speed) machining without reduction of material in spite of shearing, while at least reducing the local load on the die through reduction of friction between the die and the material through vibration transfer of the die. It is possible to further extend the life of the die.

In addition, the present invention can use the existing die for ECAP processing as it is, and can also use the existing roll roll for wire rods, etc., while extending the die life, it is possible to reduce the cost.

1 is an overall configuration diagram showing a continuous shearing apparatus given rolling in accordance with the present invention
2 and 3 is a schematic diagram showing a continuous shearing step through the rolling according to the present invention.
Figure 4 is a stress distribution diagram showing a detailed die stress distribution during continuous shearing through rolling of the present invention
5 is a schematic diagram showing the relationship between the material and the die according to the ultrasonic vibration transmission.
6 is a graph showing an example of ultrasonic vibration transmission (applied) of a die according to the present invention.
Figure 7 is a photograph showing a part excluding a rolling roll in the present invention device

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

First, Figure 1 shows the overall configuration of the load reduction type continuous shearing apparatus 1 according to the present invention.

That is, as shown in Figure 1, the load reduction type continuous shearing apparatus 1 according to the present invention, as an example of the configuration, while providing a compressive force for shear deformation to the material while providing continuous processing during shearing Vibration of the die provided to reduce the load applied to the die roll 10, the die 30 is provided to shear deformation of the material subjected to the rolling roll, and the die during machining by applying vibration to the die It may be configured to include a delivery means (50).

That is, the continuous shearing apparatus 1 of the present invention is a rolling roll 10 configured to face each other to enable the application of the compressive force by rolling the workpiece (2), and finally the material processing through the shear deformation Implementing die 30 may be provided, for example, as the die for ECAP described above.

At this time, the ECAP die 30 has a predetermined crossing angle Θ that intersects between the entry and exit sides of the channel 32, which is a material passage formed therein, in order to enable shearing. The channel includes an intersection.

Therefore, the continuous shearing apparatus 1 of the present invention can basically use a ball roll, a flat roll, or the like used during wire rod rolling as it is, without changing the special structure, and the die 30 also uses an existing die for ECAP. Enable to use without modification.

At this time, as shown in Figure 1, the rolling roll 10 is used in rolling when the ball or the ball having a circular ball portion 12 is used in the rolling of the wire rod having a circular cross-section mainly of the square material The flat roll 10 'can be used. In the following description of the present embodiment, however, the rolling roll 10 will be described collectively.

On the other hand, as shown in FIG. 1, since the present invention uses the rolling roll 10, the rolling roll is preferably arranged as close as possible to the channel inlet side of the die 30. As shown in FIG. Thus, when the prior deformation of the material, that is, compression through rolling as shown in FIG. 1, the material is exited into the exit channel 32 while additional shear deformation of the material is further generated at the channel intersections of the die.

Next, as shown in Figure 1, the continuous shearing apparatus 1 of the present invention, in particular, by implementing the vibration transmission (applied) of the die, as described in detail in the die cross section by using a rolling roll as described in detail below It is provided to prevent wear of the die by application of load due to excessive material and die contact.

For example, the vibration transmission means 50 of the die of the present invention, as shown in FIGS. 1 and 7, includes an oscillator 58 associated with the ultrasonic generator 52 and disposed to contact the die. It can be provided as a (ultrasonic) vibration transmission means of the die configured to implement the die vibration via.

At this time, more preferably, the transducer 54 and the amplifier 56 for applying the ultrasonic wave are connected between the ultrasonic generator 52 and the vibrator 58, and the vibrator 58 is a fastening means, that is, a fastening bolt 58a. ) May be provided at the distal end to allow the die transfer of ultrasonic vibrations while being closely fixed to the die.

Next, the continuous shearing method using the load-reducing continuous shearing apparatus 1 of the present invention as described above, as shown in Figures 1 to 3, basically by rolling the material (2) to provide a compressive force In particular, including the material rolling step, and the material processing step of shearing the material passed through the rolling step to enable the continuous processing.

In addition, the processing method of the present invention further includes a vibration transmission step of the die using the vibration transmission means 50 of the die described above, which is further performed in at least the material processing step of the rolling step and the material processing step.

Therefore, the continuous shearing method of the present invention, as described above, while performing the rolling step to generate a compressive force, the reduction of the reduction during processing is to enable the continuous processing that is a problem in the existing ECAP processing method. For example, the reduction of the cross section of the raw material occurs due to rolling, but the rebound force is generated by the unrolled portion that tries to escape from the channel intersection as it enters the channel, thereby recovering the cross section.

On the other hand, Figures 2a to 2d shows that in the processing of the material through the continuous shearing process according to the present invention, in particular, the cross-section of the material is reduced in cross section by the compressive force by rolling to the cross-sectional area of the initial material.

For example, as shown in FIG. 2A, first, the workpiece 2 enters into the inlet channel 32 of the die 30 and contacts at the channel intersection of the die to align to an initial position, as shown in FIG. 2B, without rolling deformation. A simple compressive force in the z-direction is applied (applied) to the workpiece, and this spreading of the workpiece is formed in the x-direction by applying a simple compressive force in the z-direction, thereby reducing the cross section of the workpiece. In this case, in FIG. 2B, the unrolled region is a region up to the material compressed portion and the material front portion.

However, as shown in FIG. 2C, when the material having the z-direction compression and the x-direction width spreading is formed, when the rolling roll 10 starts to rotate, the unrolled region is the intersection of the channel 32, that is, the entrance side. The shear deformation of the material starts at the portion having the intersection angle Θ where the channel and the exit channel intersect, and finally, as shown in FIG. 2D, when the rolling roll 10 is continuously rotated, the unrolled region At the same time a large portion exits the exit channel, at the same time a repulsion occurs in the material in the positive y direction, and when the rolled area begins to penetrate the entry channel, the spreading portion is re-deformed to fit the channel inlet size.

At this time, due to the repulsive force generated at the channel intersection and the compressive force by the rolling roll is filled into the rolled area into the side channel, and as a result sufficient contact between the die and the material is generated to recover the initial cross-sectional area.

In addition, in Fig. 3A and Fig. 3B, the cross-sectional recovery of the raw material 2 which has passed through the rolling roll is shown in more detail.

For example, as shown in FIG. 3A, the spreading portion is deformed again as the rolling region S1 is introduced into the channel, and sufficient contact S2 occurs with the surface of the entry channel, while maintaining sufficient contact between the material and the die. It can be seen that the shear deformation S3 takes place. However, FIG. 3A shows the process for the wire rod which is a circular raw material in cross section, and FIG. 3B shows the case where the material which is the same shear deformation process is a square material.

That is, a sufficient contact is generated means that the area of the portion reduced by rolling is recovered, and this process occurs continuously, thereby enabling continuous rigid plastic processing without cross-sectional reduction.

After all, the conventional rigid plastic processing is intended to maintain the initial cross-sectional area to the maximum, but the present invention is to induce the cross-sectional change to generate the compression force required for shear deformation.

By the way, during the continuous shearing process using such a rolling wear of the die occurs. For example, in the case of drawing, the reduction is made uniformly through the die of the axisymmetric shape, but the ECAP processing with the addition of rolling as in the present invention is basically based on the shear deformation at the channel intersection. Since the ECAP process is based on, the material is processed asymmetrically.

As a result, a locally large contact pressure is applied at the channel intersection of the die 30, which, according to the wear equation (Equation 1) below, directly affects the wear pressure. It can be seen that.

[Equation 1]

W = ∫ (K × ((P ^a v ^b ) / H ^c )) dt

Where W is the loss volume, P is the internal pressure, v is the slip coefficient, H is the hardness, and a, b, c, and K are constants.

On the other hand, Figure 4 shows the distribution of the tensile stress value generated in the die during continuous shearing (ECAP-Rolling) processing with the rolling of the present invention, the channel 32 of the die 30 cross It can be seen that the largest tensile stress acts at the inner corners (edges) even in the region of

Therefore, if the tensile stress value applied at the die, particularly at the corner of the channel intersection, is greater than the tensile strength of the material of the die, fracture occurs, and in particular, wear of the die is rapidly amplified.

However, in the case of continuous shearing using the load-reducing continuous shearing apparatus 1 of the present invention, since the fine vibration is generated by applying ultrasonic waves to the die through the vibration transmitting means 50 of the die, the die To suppress wear.

For example, at the time of shearing the raw material to which the rolling of the present invention is added, as shown in FIGS. 2 and 3, since the reduction of the raw material 2 does not occur, the shape of the die is changed to suppress wear. In this case, since the advantages obtained in the continuous processing of the present invention are lost, the present invention suppresses die wear without changing the shape of the die through the vibration (ultrasound vibration) transmission to the die.

On the other hand, Figure 5a to 5c corresponds to the case of drawing (drawing), schematically showing the principle according to the die transfer of the ultrasonic vibration, for example, in the case that the die is not applied in Figure 5a 5 (b) and (c) show a case where ultrasonic vibration is transmitted (applied) to the die in the material traveling direction and the vertical direction of the material traveling direction, respectively.

5A to 5C are described, for example, in the reference "M. Murakawa, M. Jin, The utility of radially and ultrasonically vibrated dies in the wire drawing process, Journal of Materials Processing Technology 113 (2001) 81-86". It is presented.

Thus, as shown in FIG. 5A, when ultrasonic vibration is not transmitted, the channel 32 of the die 30 and the material 2 are in continuous contact during processing, while as shown in FIGS. 5B and 5C, several micrometers are used. It can be seen that when the ultrasonic vibration having an amplitude of about a meter acts in the direction in which the material proceeds or perpendicular to the direction of travel, the contact between the die 30 and the material 2 is momentarily dropped and then contacted again.

By transmitting ultrasonic vibration to the die such that the process of contact-> non-contact-> re-contact between the die and the material occurs continuously during processing, the die frictional force of the material is reduced, and as a result, the load applied to the die is reduced. To reduce. In this case, in FIG. 5, D0 to D4 and W0 to W4 represent the inner diameter of the channel and the width of the material, respectively.

As a result, in the case of using the load-reducing continuous shearing apparatus 1 of the present invention, as shown in Figs. 1 and 7 (Fig. 7 is a photograph showing a portion excluding a rolling roll in the apparatus of the present invention), the material 2 Is entrained by rolling at the inlet side of the die 30.

At this time, the vibration transmitting means 50 of the die, that is, the ultrasonic vibration transmitting means of the die generates ultrasonic waves in the ultrasonic generator 52, converts the ultrasonic vibration in the associated transducer 54, and the associated amplifier 56 When amplified to the desired amplitude at, it is transmitted to the vibrator 58 connected to the amplifier to apply vibration to the wall of the die 30.

On the other hand, as shown in Figure 1, the front end of the vibrator 58 has a thread is attached to the wall (outer wall surface) of the die by the fastening bolt (58a), the actual vibration is transmitted to the die 30 by the vibrator (58). .

Preferably, the vibration is such that the inlet and outlet channels of the die 30 are located on the same line as the intersection where the intersections of the dies 30 intersect with each other. to be.

More preferably, the direction in which the vibration is applied to the die is such that it is horizontal in the direction in which the material proceeds or is perpendicular to the direction in which the material travels, which is a periodic contact between the die 30 and the material due to the principle of ultrasonic vibration. Since it is repeated to reduce the friction, it is to maximize the effect.

On the other hand, Figure 6 is a graph showing the load reduction effect through the die transfer of the ultrasonic vibration of the present invention, for example, the cross-sectional diameter of the die channel 32 is 10 mmφ, the diameter of the material 2 9.8 mmφ, In the case of processing the material with 0.8% C carbon steel in the die 30 of the present invention (e.g., ECAP die) having a channel cross angle Θ of 120 °, the ultrasonic vibration is transmitted to the die (vibration section), It can be seen that the maximum decrease from 152 kN to 126 kN.

For example, in FIG. 6, it can be seen that the load is reduced to 126 kN in the vibration application section (vibration section) of the dotted line for applying ultrasonic vibration to the die.

Accordingly, during continuous shearing of the present invention through the load-reducing continuous shearing apparatus 1 of the present invention described above, material reduction is not generated while generating a compressive force through rolling, so that shear deformation and continuous This allows for (fast) machining, in particular to reduce the load on the die, in particular the channel intersections of the die, thereby extending the life of the die.

As a result, the present invention utilizes an existing ECAP die, a ball rolling roll, and the like, and extends the die life without changing the die structure, thereby enabling cost reduction in terms of equipment or process.

1 .... continuous shearing apparatus of the present invention 10 .... rolling roll
30 ... die 32 ... channels
50 .... means of transmitting vibration of die 52 .... ultrasonic generator
54 .... Converter 56 .... Amplifier
58 .... vibrator

Claims (6)

A rolling roll provided to apply a compressive force for shear deformation of the material;
A die provided to shear deformation of the material subjected to the rolling roll; And,
Vibration transmission means of the die provided to reduce the load on the die;
Continuous shearing device configured to include.
The method of claim 1,
The die includes a channel having a cross section to enable shear deformation, and the vibration transmitting means of the die includes a vibrator provided to transmit ultrasonic vibration to the die in association with the ultrasonic generator. Device .
Rolling material to provide a compressive force for shear deformation of the material; And,
A material processing step in which the material is sheared at the die;
Including continuous processing,
Vibration transmission step of the die is carried out in at least the material processing step of the rolling step and the material processing step;
Continuous shear processing method configured to further comprise.
The method of claim 3,
In the material rolling step, using the rolling roll of the ball roll or flat roll is inserted into the rolling material to the intersection of the die, while applying a compressive force to the inserted material, the preceding deformation of the material is made,
In the material processing step, after the preceding deformation of the material, the shear deformation of the material is made at the channel cross-section of the die during rolling, and the initial cross-sectional area is restored by making sufficient contact with the die by the repulsive force of the material at the channel cross-section. Continuous shearing method.
The method according to claim 3 or 4,
The vibration transmission step of the die, continuous shearing method characterized in that for transmitting the ultrasonic vibration to the die through a vibrator disposed in close contact with the die.
The method of claim 5,
In the vibration transmission step of the die, the ultrasonic vibration is applied to the channel intersection of the die after the die filling of the material,
The ultrasonic vibration is continuous shearing method characterized in that applied in the horizontal or vertical direction of the material traveling direction.

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