KR20190041593A - Surface strengthening method and surface strengthened mold formed by applying the same - Google Patents

Abstract

According to an embodiment of the present invention, a surface strengthening method comprises the following steps of: preparing a plate; forming a plurality of filling grooves on a surface of the plate; forming a filling unit by filling a filling material in the filling groove; and forming a reforming unit on a surface of the plate by stirring the plate surface on which the filling unit is formed with a friction stir machine. The reforming unit is formed by stirring the filling material and a component of the plate.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface strengthening method and a surface strengthening method,

The present invention relates to a surface strengthening method and a surface strengthening mold formed by applying the same. More particularly, it is possible to form a filling groove on the surface of a plate and fill the filling groove with a filler to uniformly distribute the filler on the surface of the plate And a surface strengthening method capable of maximizing the effect of surface modification by modifying the surface of the plate with a uniform reforming portion by friction stir, by enabling quantitative control of the filler.

Generally, friction stir welding refers to a welding method in which two materials to be welded are brought into contact with each other, and then a friction stir welding tool is contacted and rotated at a contact portion (welding portion) of the two materials to be welded to bond the two materials to be welded.

That is, friction stir welding is a technique that has been developed for solid state bonding to metal materials, generally as a solid state process.

Friction heat is generated between the friction stir welding tool and the welded portion by the high-speed rotation of the friction stir welding tool. The friction stir welding tool softens and agitates the welded portion with frictional heat generated by its rotation, and as a result, the two bonded materials are bonded.

The friction stir welding does not require any additional heat source, welding rod, or solvent, and does not emit harmful rays or harmful substances during the welding process. Therefore, it is evaluated as an economical and environmentally friendly welding method.

Since the friction stir welding is a method of welding with low heat as compared with the conventional fusion welding, it is a welding method suitable for joining between functionally unweldable materials such as aluminum and magnesium having high oxidation resistance at high temperatures.

In recent years, friction stir welding has also been used not only for lightweight alloys but also for bonding between high melting point materials such as titanium, stainless steel, and nickel alloys.

The above-mentioned friction stir welding is also used for a method of totally or locally modifying the surface by contacting a high-speed rotating tool to the surface of one material other than the welding method of joining the two materials to be bonded.

The surface modifying method using friction stir is a method to improve the surface characteristics of parts for mechanical structural parts. There are a method of refining a part of the surface of the material by using frictional heat and a method of modifying the surface with a reinforcing agent There is a way to do this. All of these can form a film that is refined on the surface of the material due to the frictional heat, or a film mixed with the reinforcing agent.

Here, the method of microstructuring using only frictional heat has a limitation in enhancing the surface characteristics only by the microstructure implementation.

In the method of strengthening the surface by providing the reinforcing agent on the surface, there is a problem that the reinforcing agent provided on the surface of the material is scattered by the high-speed rotation tool, and it is difficult to uniformly form the coating by simply applying the reinforcing agent to the surface of the material Can exist. In addition, when a reinforcing agent is used, there is a problem that the coating can be released.

As described above, when the surface of the material is strengthened by the friction stir, it is difficult to quantitatively control the reinforcing agent due to problems such as scattering of the functional reinforcing agent on the surface and scattering of the functional enhancer, so that the effect of the reinforcing agent is maximized There is a limit.

Therefore, it is necessary to quantitatively control the functional strengthening agent and improve the process to maximize the effect of the reinforcing agent by the homogeneous distribution of the strengthening agent.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for manufacturing a plate, which comprises filling grooves on a surface of a plate and filling a filler in the filling grooves to uniformly distribute the filler on the surface of the plate, Which is capable of modifying the surface of a substrate with a uniform reforming portion.

It is another object of the present invention to provide a surface strengthening method capable of maximizing the effect of surface modification by forming a uniform modified portion.

It is another object of the present invention to provide a surface strengthening mold capable of uniformly distributing a filler on the surface of a plate by the above surface strengthening method and capable of quantitatively controlling a filler to thereby improve productivity.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. There will be.

According to an aspect of the present invention, there is provided a surface strengthening method including preparing a plate, forming a plurality of fill grooves on a surface of the plate, filling the fill groove with the filler, And forming a modified portion on the surface of the plate by stirring the plate surface formed with the filler portion using a friction stirrer, wherein the modifying portion is formed by stirring the components of the filler and the plate .

The plate may be formed of at least one selected from a single metal, an alloy, a composite, and a mixture thereof.

The filling groove may be formed by a method of chemically etching a part of the surface of the plate, a method of drilling a part of the surface of the plate with a laser, , A method of diamond drilling, a method of using plastic deformation by pressure, and a mixed method thereof.

The filling grooves may be formed in the range of 15 탆 to 15 탆 from the surface of the plate toward the inside of the plate.

The spacing distance between the filling grooves and the adjacent filling grooves may be in the range of 10 탆 to 1 mm.

Wherein the filling agent is applied to the surface of the plate by a method selected from a blade, a squeegee, and a mixing method in which the filler is filled in the filling groove to form a filling part, Can be drawn into the filling groove.

The filler may be at least one selected from a metal material, a non-metal material, a carbon-based material, a metal carbide, a ceramic powder, and a mixture thereof.

The filler may be a material which is mixed with the components of the plate and strengthens at least one of mechanical strength, thermal conductive physical properties and chemical characteristics of the plate surface.

In the step of filling the filling groove with the filler to form the filling part, the exposed surface of the filling part may be formed flush with one surface of the plate.

The diameter of the filling part may be in the range of 100 μm to 10 mm.

The step of stirring the plate surface formed with the filling part using a friction stirrer to form a modified part on the surface of the plate may include stirring the plate surface at a speed of 0.1 mm / sec to 100 mm / sec have.

The friction stirrer may be rotated at a speed of 100 rpm to 2000 rpm.

The friction stirrer may include a body portion and a high-speed rotation tool protruding from the body portion to be inserted into the plate, wherein a depth of insertion of the high-speed rotation tool may be in a range of 10 탆 to 10 mm.

According to another aspect of the present invention, a surface strengthening mold is formed by the surface strengthening method.

The modifying portion may be formed on one surface of the plate in a range of 20 탆 to 20 탆.

According to another aspect of the present invention, there is provided a surface strengthening method comprising:

According to the embodiment of the present invention, the surface strengthening method can form fill grooves on the plate surface and fill the fill grooves in the fill grooves to uniformly distribute the fillers on the surface of the plate, and to control the fillers quantitatively, It is possible to modify the surface of the plate with a uniform reforming portion.

Further, by applying a surface strengthening method to form a uniform modified portion, the effect of surface modification can be maximized.

Also, by applying the surface strengthening method, the surface strengthening mold can uniformly distribute the filler on the surface of the plate, and it is possible to control the filler quantitatively, thereby improving the productivity.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a flowchart showing a surface strengthening method according to an embodiment of the present invention.
FIGS. 2 to 5 are process drawings showing a surface strengthening method according to an embodiment of the present invention.
6 is a cross-sectional view taken along line I-I 'of FIG.
7 is a sectional perspective view showing a surface strengthening mold to which the surface strengthening method according to Embodiment 1 of the present invention is applied.
8 is a cross-sectional perspective view showing a surface strengthening mold to which the surface strengthening method according to the second embodiment of the present invention is applied.
9 is a graph showing the hardness distributions of the surface strengthening molds according to the first and second embodiments of the present invention.
10 is a graph illustrating impact characteristics of a surface enhanced mold according to embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" (connected, connected, coupled) with another part, it is not only the case where it is "directly connected" "Is included. Also, when an element is referred to as " comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

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

FIG. 1 is a flow chart illustrating a surface strengthening method according to an embodiment of the present invention, FIGS. 2 to 5 are process charts illustrating a surface strengthening method according to an embodiment of the present invention, FIG. 6 is a cross- Fig.

Referring to FIG. 1, a surface strengthening method according to an embodiment of the present invention includes preparing a plate (S100), forming a plurality of filling grooves 210 on the surface of the plate (S200) A step S300 of forming a filling part 400 by filling the filling groove 310 with the filler 310 and a step of stirring the surface of the plate 110 where the filling part 400 is formed by using a friction stirrer 500 And forming a reforming portion 600 on the surface of the plate 110 (S400).

Here, the reforming part 600 is formed by stirring the components of the filler 310 and the plate 110.

As described above, in the surface strengthening method according to the embodiment of the present invention, the fill groove 210 is formed on the surface of the plate 110, the filler 310 is filled in the fill groove 210, The surface of the plate 110 can be uniformly modified by the friction stir welding because the filler 310 can be uniformly distributed and the quantitative control of the filler 310 can be performed.

Further, by applying the surface strengthening method to form a uniform reforming portion 600, the effect of surface modification can be maximized.

Hereinafter, the process diagram and the flowchart will be described in detail by matching.

Referring to FIGS. 1 and 2, a surface strengthening method according to an embodiment of the present invention includes a step of preparing a plate 110 (S100).

The plate 110 may be at least one selected from a single metal, an alloy, a composite, and a mixture thereof. For example, a metal matrix composite, a ferrous alloy, such as steel and stainless steel, and non-ferrous materials.

The plate 110 may have a plate shape, a predetermined bent shape, a folded shape, or the like. However, the shape of the plate 110 is not limited thereto, and any shape having a surface capable of performing later- Shape.

Referring to FIGS. 1 and 3, a step S200 of forming a plurality of filling grooves 210 on the surface of the plate 110 is performed.

It is preferable that the filling groove 210 is formed with a plurality of grooves to control the filling amount of the filling agent 310 disposed in the filling groove 210 later. For example, when the shape of the filling groove 210 is large, it is difficult to uniformly form the reforming portion 600 due to the excessive placement of the filling agent 310 in a certain region. When the filling groove 210 is too small, It may be difficult to quantitatively control the filler 310 with the filler 310. Accordingly, it is preferable that the filling grooves 210 are formed in a predetermined shape and are arranged in plural to solve the above-mentioned problems.

A fill groove 210 is formed in the interior of the plate 110 at the surface of the plate 110. The filling groove 210 may be formed in the range of 15 to 15 mm in the inner direction of the plate 110 at the surface of the plate 110. The shape of the filling groove 210 will be described in detail later with the filling part 400 in FIG.

The filling groove 210 may be formed by a method of chemically etching a part of the surface of the plate 110, a method of drilling a part of the surface of the plate 110 with a laser, a method of physically drilling a part of the surface of the plate 110, A method of using plastic deformation by pressure, and a mixed method thereof.

For example, in the case of a method of chemically etching a part of the surface of the plate 110, a photosensitive photoresist may be applied on the surface of the plate 110 to form a photoresist layer. A portion of the photoresist layer can be cured by irradiating UV onto the photoresist layer using a mask. Thus, the photoresist layer can be divided into a hardened region and a non-hardened region.

Then, a portion of the surface of the plate 110 may be exposed by removing either the hardened region or the uncured region of the photoresist layer using a develop process. Wherein the fill groove 210 can be controlled by the shape of the exposed surface.

The exposed plate surface may be etched by providing an etchant on the exposed area of the surface of the plate 110 from the photoresist. Here, the kind of the etchant and the time for carrying the etchant are not particularly limited as they are different depending on the material of the plate 110.

Further, the depth of the filling groove 210 can be controlled by controlling the holding time of the etching liquid.

When the etchant is neutralized and the photoresist is removed on the surface of the plate 110, a filling groove 210 may be formed on the surface of the plate 110.

Alternatively, a non-contact energy such as a laser beam or an electron beam may be externally provided on the surface of the plate 110 to form the filling groove 210.

Here, the method of forming the filling grooves 210 by providing noncontact energy such as a laser beam or an electron beam may be performed after the high-purity reforming portion 600 is formed due to no foreign matter or physical / chemical impact on the surface of the plate 110. [ Can be formed. Hereinafter, a method of externally providing non-contact energy such as a laser or an electron beam is generally referred to as laser drilling.

Laser drilling can control the depth (reference P in FIG. 6) or diameter (Q in FIG. 6) of the filling groove 210 on the surface of the plate 110 by controlling the intensity of the laser. Here, the laser intensity of the laser drilling is not particularly limited as it depends on the material of the plate 110.

Meanwhile, the filling grooves 210 may be selectively disposed on the front surface or only a part of the surface of the plate 110. In other words, when the filling grooves are formed on the front surface of the plate, the surface is strengthened on the entire surface of the plate, and when filling grooves are formed on some of the plates, the surfaces having mechanical and chemical intensity concentrated on some areas are strengthened.

The spacing D between the filling grooves 210 and the adjacent filling grooves 210 may be in the range of 10 탆 to 1 mm.

If the spacing distance D between the filling grooves 210 is less than 10 탆, the number of forming the filling grooves 210 is increased and the process may be difficult to reduce the process efficiency. In the process of forming the filling grooves 210, The filling grooves 210 may be formed in a shape that is difficult to control the filling amount of the filling material 310 at a later time.

When the spacing distance D between the filling grooves 210 is more than 1 mm, the distance between the filling grooves 210 is increased, and the region where the filler 310 and the material of the plate 110 are mixed unevenly due to friction stir occurs later . That is, the components of the reforming unit 600 to be formed later may be non-uniformly formed, which may cause a decrease in efficiency of surface strengthening.

By forming the filling grooves 210 on the plate 110, a structure capable of physically quantifying the filler 310 can be provided.

Referring to FIGS. 1 and 4, a filler 310 is filled into a fill groove 210 to form a filler 400 (S300). Hereinafter, a more detailed description will be made with reference to FIG.

First, the filler 310 may be mixed with the components of the plate 110 to use a material capable of enhancing at least one of mechanical strength, thermal conductive physical properties, and chemical characteristics of the surface of the plate 110.

For example, the filler 310 may be at least one selected from a metal material, a non-metal material, a carbon-based material, a metal carbide, and a ceramic powder. As another example, the filler 310 includes, but is not limited to, any one selected from the group consisting of chromium, molybdenum, tungsten, aluminum, titanium, niobium, tantalum, and rhenium and mixtures thereof.

The filler filling method of the surface strengthening method according to an embodiment of the present invention may include filling the filler 210 on the surface of the plate 110 by any one of squeegee, blade, A method of pushing the filler 310 into the filling groove 310 can be used.

For example, a method of filling the filler 310 using the blade 900 will be described. First, a filler 310 formed of powder is applied to one surface of the plate 110. The blades 900 may be attached to the surface of the plate 110 and the blades 900 may be pushed in one direction to allow the filler 310 applied on the plate 110 to enter the fill grooves 210.

Here, the step of pushing the blade 900 can be repeatedly performed so that the filler 310 is sufficiently drawn into the fill groove 210, and the pushing direction can be set in various directions to increase the pull-in probability.

The filler 310 formed of powder may be easy to draw the filler 310 into the filler groove 210, but it may be difficult to quantitatively control the filler amount due to high scattering probability due to the powder shape.

As another example, there is a method of forming a viscous body by mixing a filler 310 formed of powder with a binder. A filler 310 modified to a viscous material by the binder may be applied to one surface of the plate 110 and the filler 310 may be introduced into the filler groove 210 through the blades 900.

The binder can be a binder that does not affect the components of the reforming unit 600 because of the ignition loss due to the frictional heat generated in the subsequent friction stir.

Thus, the filler 310 can be used to control the filler 310 quantitatively, and the filler 310 can be uniformly distributed on the surface of the plate 110.

Also, the filling amount of the filler 310 can be controlled by the filler 310 filling method of the surface strengthening method according to the embodiment of the present invention.

6, the filler 310 is filled in the fill groove 210 to form the filler 400. The exposed surface 450 of the filler 400 is exposed to the surface of the plate 110 And the second surface of the second substrate. In other words, one surface of the plate 110 may be formed such that the surface of the plate 110 and the filling part 400 are exposed and coplanar.

In this way, the filling amount of the filler 310 can be controlled by forming the exposed surface 450 of the filling part 400 and one surface of the plate 110 to be flush with each other.

For example, the number of the filling grooves 210 and the shape of the filling grooves 210 can be controlled in step S200 of forming the filling grooves 210. [ Here, there is a limit to quantitatively control the filling amount (hereinafter referred to as " filling amount ") of the filling agent 310 only by the shape of the filling groove 210 and the number of the filling grooves 210. Therefore, in order to quantitatively control the filling amount, the amount of the filler 310 to be filled in the filling groove 210 may be important.

Here, the exposed surface 450 of the filling part 400 may be formed to be flush with one surface of the plate 110 to control the filling amount.

For example, when the filler 310 is partially filled in the filler groove 210, it may be difficult to realize the filler 310 to be partially filled. That is, only a part of the filler 310 may be filled in the fill groove 210, and a region where the filler 310 is not filled may occur in the fill groove 210 of another region.

In the opposite case, the filler 310 may be excessively filled in the filler groove 210. In the case of overfilling, some may become overfilled and some may be unfilled.

In this case, the reference is required for the filler 310 so that one surface of the plate 110 and the exposed surface of the filler 400 are flush with each other, So that the filling amount can be controlled. In other words, the surface of the plate 110 may be formed such that the filler 310 is exposed on a surface of the plate 110.

Meanwhile, the spacing D between the filling part 400 and the adjacent filling part 400 may be in the range of 10 탆 to 1 mm.

When the spacing distance D between the filling parts 400 is less than 10 mu m, the shape of the filling part 400 may be enlarged by being connected to the adjacent filling groove 210 in the process of forming the filling groove 210. [ That is, the filling part 400 may be formed in a shape difficult to control the filling amount of the filling material 310.

In other words, as the shape of the filling part 400 increases, the filler 310 is excessively supplied to the local area so that the filler 310 is not uniformly dispersed, and thus the modification part 600 different from the surrounding composition can be formed . That is, as the filler 310 is excessively supplied to a certain region, a relatively hardened region is generated, and the hardness of the peripheral region is relatively low, so that the modified portion 600 can be easily formed.

When the spacing distance D between the filling parts 400 is more than 1 mm, the distance between the filling parts 210 is increased, and there is a region where the filler 310 and the material of the plate 110 are unevenly mixed due to friction stir . That is, the components of the reforming unit 600 to be formed later may be non-uniformly formed, which may cause a decrease in efficiency of surface strengthening.

In other words, the hardness of a part of the area of the reforming part 600 is increased, while the mixing of the filler 310 and the material of the plate 110 does not occur in some areas, so that a relatively low hardness area may be generated. That is, the uniformity of the reinforced area is lowered, which may cause a decrease in the reinforcing efficiency.

As described above, the surface strengthening method according to the embodiment of the present invention can uniformly distribute the filler 210 at a spacing interval of the filler 400 and enable quantitative control of the filler 210.

Also, the filling part 400 may be formed in the range of 15 to 15 mm in the inner direction of the plate 110 at the surface of the plate 110. The forming depth P of the filling part 400 and the forming depth P of the filling groove 210 may be the same.

If the depth P of the filling part 400 is less than 15 mu m, the filler 310 may not be sufficiently filled due to the particle size of the filling material 310 disposed in the filling groove 210, A problem similar to that in the case of coating on In addition, filling amount of the filler 310 may be small in the filling part 400, so that it may be difficult to form the reforming part 600 having enhanced characteristics.

When the depth of the filler portion 400 exceeds 15 mm, the filler 210 (210 in FIG. 5) may be positioned more deeply than the depth at which the high speed rotation tool of the friction stir And the components of the plate 110 may be difficult to stir together.

In other words, there may be a region where the filler 210 and the plate 110 are not agitated due to the depth of the filler 400 despite the friction stir. Therefore, the filler 210 may cause the surface strengthening efficiency of the surface of the plate 110 to be lowered in the region where the filler 210 is not stirred.

The diameter Q of the filling part 400 may be in the range of 100 μm to 10 mm. Here, the diameter Q of the filling part 400 may be the same as the diameter of the filling groove 210. Also, the diameter of the filling part 400 may not be a circle but may be a square or a triangle. The average size of the filling part 400 is defined as a diameter.

If the diameter Q of the filling part 400 is less than 100 탆, the efficiency of drawing the filling material 310 into the filling groove 210 may be lowered and the uniform dispersion of the filling material 310 may be lowered.

When the diameter Q of the filling part 400 is more than 10 mm, it is difficult to realize the characteristics such as the uniform target hardness of the reforming part 600 because the filler 310 disposed in the filling part 400 is excessively supplied . That is, due to the filling amount of the filler 310 supplied in an excess amount, it is difficult to realize a uniform hardness due to a relatively low hardness and the like in a part of the modified part 600, The overall hardness and the like may be lowered.

As described above, according to the surface strengthening method of the present invention, the filling groove (210) is formed on the surface of the plate (110), and the filler (310) The filler 310 can be uniformly distributed on the surface of the plate 110 and quantitative control of the filler 310 can be performed.

1 and 5, a step of stirring a surface of a plate 110 on which a filling part 400 is formed using a friction stirrer 500 to form a modified part 600 on the surface of the plate 110 S400).

First, the friction stirrer 500 may include a body portion and a high-speed rotation tool 550 protruding from the body portion. The high-speed rotation tool 550 may be inserted into a part of the surface of the plate 110. [

The inserted high-speed rotation tool 550 rotates to generate frictional heat to synthesize the material of the filler 310 and the plate 110 to form the reforming part 600. In other words, the reforming unit 600 may be formed of an alloy, a metal complex, or the like in which the material of the filler 310 and the material of the plate 110 are combined.

Here, the rotation speed of the high-speed rotation tool 550 of the friction stirrer 500 may be rotated at a speed of 100 rpm to 2000 rpm. If the rotation speed of the high-speed rotation tool 550 is less than 100 rpm, the generation of frictional heat due to rotation is insignificant and may be agitated. If the rotation speed of the high-speed rotation tool 550 exceeds 2000 rpm, One can consume more energy.

Meanwhile, the depth of insertion of the high-speed rotation tool 550 may be in the range of 10 μm to 10 mm. When the depth of insertion of the high-speed rotation tool 550 is similar to the depth P of the filling groove 210, the uniform reforming portion 600 can be formed. However, it is practically difficult to form the depth of insertion of the high-speed rotation tool 550 and the depth P of the filling groove 210 as described above.

The depth P of the filling groove 210 may be larger than the depth of the high-speed rotation tool 550 inserted. This is because the material of the plate 110 and the material of the filler 310 are mixed with each other due to frictional heat generated by the high-speed rotation tool 550 and diffusion of the material occurs, As shown in FIG.

Therefore, it is preferable that the depth of insertion of the high-speed rotation tool 550 is in the range of 10 to 10 mm.

When the insertion depth of the high-speed rotation tool 550 is less than 10 占 퐉, the insertion depth at which frictional heat may occur is low, and frictional heat may not be sufficiently generated. Moreover, there may be a difficulty in stirring the filler 310 disposed in the filler part 400 by inserting it at a lower depth as compared with the forming depth P of the filling groove 210.

In other words, the region where the filler 310 is not stirred may remain because the insertion depth of the high-speed rotation tool 550 is low. The remaining filler 310 may cause defects of the reforming unit 600 and may deteriorate the performance of the reforming unit 600.

If the insertion depth of the high-speed rotation tool 550 is more than 10 mm, the amount of material of the plate 110, which is deeply inserted and stirred into the plate 110, may increase. The density of the filler 310 in the reforming unit 600 is lowered and the density of the filler 310 in the reforming unit 600 is lowered as compared with the amount of the filler 310 in the filler 400, May be deteriorated.

Therefore, in the surface strengthening method according to the embodiment of the present invention, the depth of insertion of the high-speed rotation tool 550 is controlled to be in the range of 10 탆 to 10 mm to form a uniform reforming part 600, thereby maximizing the effect of surface modification .

Also, the stirring speed of the friction stirrer 500 may be such that the surface of the plate 110 is stirred at a speed of 0.1 mm / sec to 100 mm / sec.

If the stirring speed of the friction stirrer 500 is less than 0.1 mm / sec, the stirring speed is too slow to lower the productivity. If the stirring speed of the friction stirrer 500 is more than 100 mm / sec, Stirred regions may be present.

As described above, according to the embodiment of the present invention, the surface strengthening method includes forming the fill groove 210 on the surface of the plate 110, filling the fill groove 210 with the filler 310, The filler 310 can be uniformly distributed and the filler 310 can be quantitatively controlled so that the surface of the plate 110 can be modified into the uniform reformer 600 by friction stir.

Further, by applying the surface strengthening method to form a uniform reforming portion 600, the effect of surface modification can be maximized.

FIG. 7 is a sectional perspective view showing a surface strengthening mold to which the surface strengthening method according to Embodiment 1 of the present invention is applied, FIG. 8 is a sectional perspective view showing a surface strengthening mold applying the surface strengthening method according to Embodiment 2 of the present invention And FIG. 9 is a graph showing the hardness distribution of the surface strengthening mold according to the first and second embodiments of the present invention, and FIG. 10 is a graph showing the impact characteristics of the surface strengthening mold according to the embodiments of the present invention to be.

7 to 10 will be described with reference to Figs. 1 to 6 for ease of explanation while avoiding redundant description.

Fig. 7 shows a surface strengthening mold 10 formed by applying a surface strengthening method according to embodiment 1 of the present invention. The surface strengthening mold 10 includes a plate 110 and a reforming portion 600 formed on one surface of the plate 110. The plate 110 is made of a metal. Here, the reforming part 600 is formed in a part of the surface of the plate 110.

Here, the reforming portion 600 may be formed on one surface of the plate 110 in a range of 20 to 20 mm.

8, the mold 1000 of the second embodiment is shown. In the mold 1000, the reinforcing layer 700 is formed on the surface of the plate 110. Here, the reinforcing layer 700 is formed by applying a reinforcing agent to the filling grooves 210 formed on the surface of the plate 110, and by friction-stirring the surface of the plate 110 coated with the reinforcing agent.

Referring to FIG. 9, the hardness distribution of the surface-strengthening mold 10 according to the embodiments of the present invention is compared with the hardness distribution of the comparative example. Here, the hardnesses of the reforming part 600, the reinforcing layer 700 and the comparative example plate 110 formed on the plate 110 according to the embodiment of the present invention are compared.

Here, in order to compare the hardness distributions of the surface strengthening molds 10, 1000 according to the embodiments of the present invention, the hardness of the surface of the plate 110 was measured as a comparative example.

In Comparative Examples and Examples 1 and 2, the measurement was carried out at the same specimen size in order to increase the accuracy of the comparison data. In Comparative Examples and Examples 1 and 2, the friction stirrer 500 was rubbed at a rotation speed of 800 rpm to 200 mm per minute Lt; / RTI >

First, as a comparative example, the hardness of the plate 110 was measured from 270 HV to 330 HV.

In Example 2, the hardness of the reinforcing layer 700 formed on the plate 110 was measured from 470 HV to 530 HV.

The hardness of the modified portion 600 formed on the surface strengthening mold according to Example 1 of the present invention was measured from 480 HV to 600 HV.

In Example 1, the hardness was measured to be rather high, but in the case of the hardness uniformity, the uniform hardness was not exhibited. On the other hand, in Example 2, the hardness was measured to be uniform hardness.

In Example 2, it was judged that uniform hardness was measured due to uniform stirring and quantitative filling. In Example 1, it was judged that uniform stirring or quantitative filling did not occur and uniformity was slightly lowered do. However, as compared with the comparative example, it can be seen that the hardness is effectively increased in Examples 1 and 2.

Therefore, the surface strengthening molds 10 and 1000 according to the embodiments of the present invention can homogeneously distribute the filler 310 on the surface of the plate 110 and enable quantitative control of the filler 310, The surface of the plate 110 can be reformed into the reforming portion 600 or the strengthening layer 700 having uniform hardness.

As described above, the surface strengthening mold according to the embodiment of the present invention can maximize the effect of the surface modification by forming the uniform reforming portion 600 by applying the surface strengthening method.

10, in the comparative example, the impact absorption energy of the plate 110 was measured to be 18J.

In Example 2, the impact absorption energy of the reinforcing layer 700 formed on the plate 110 was measured to be 22J.

In Example 1, the impact absorption energy of the reforming portion 600 formed in the surface strengthening mold 10 was measured to be 24J.

Therefore, the surface strengthening molds 10 and 1000 according to the embodiments of the present invention can uniformly distribute the filler 210 on the surface of the plate 110 and enable quantitative control of the filler 210, The surface of the plate 110 can be reformed into the reforming portion 600 or the strengthening layer 700 having uniform hardness.

As described above, the surface strengthening mold according to the embodiment of the present invention can maximize the effect of the surface modification by forming the uniform reforming portion by applying the surface strengthening method.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

10: Surface strengthened mold
110: Plate
210: filling groove
310: filler
400: filling part
500: Friction stirrer
550: High-speed rotation tool
600:
D: Distance between filling parts
P: Depth of filling part
Q: Diameter of filling part

Claims (16)

Preparing a plate;
Forming a plurality of fill grooves on the surface of the plate;
Filling the filling groove with a filler to form a filling part;
Stirring the plate surface formed with the filling part using a friction stirrer to form a modified part on the surface of the plate; Lt; / RTI >
Wherein the modifying unit comprises:
Wherein the filler and the components of the plate are agitated. The method according to claim 1,
Wherein the plate is formed of at least one selected from a single metal, an alloy, a composite, and a mixture thereof. The method according to claim 1,
Forming a fill groove on the surface of the plate,
The filling groove
A method of chemically etching a part of the surface of the plate, a method of drilling a part of the surface of the plate with a laser, a method of physically drilling a part of the surface of the plate, a diamond drilling method, a method of using plastic deformation by pressure, Wherein the surface strengthening method is formed by any one selected from a mixed method. The method according to claim 1,
Wherein the filling groove is formed in a range of 15 탆 to 15 탆 from the surface of the plate toward the inside of the plate. The method according to claim 1,
Wherein the spacing distance between the fill grooves and the adjacent fill grooves is in the range of 10 탆 to 1 탆. The method according to claim 1,
In the step of filling the filling groove with the filler to form the filling part,
Preferably,
Wherein the filler applied to the surface of the plate is introduced into the filling groove by a method selected from a blade, a squeegee, and a mixing method of mixing them. The method according to claim 1,
Wherein the filler is at least one selected from a metal material, a nonmetal material, a carbon-based material, a metal carbide, a ceramic powder, and a mixture thereof. The method according to claim 1,
Wherein the filler is a material which is mixed with the components of the plate and strengthens at least one of the mechanical strength, thermal conductive physical properties and chemical characteristics of the plate surface. The method according to claim 1,
In the step of filling the filling groove with the filler to form the filling part,
Wherein the exposed surface of the filler is coplanar with a surface of the plate. The method according to claim 1,
And the diameter of the filling part is in the range of 100 탆 to 10 탆. The method according to claim 1,
Stirring the plate surface formed with the filling part using a friction stirrer to form a modified part on the surface of the plate,
Wherein the friction stirrer agitates the plate surface at a rate of 0.1 mm / sec to 100 mm / sec. The method according to claim 1,
Wherein the friction stirrer is rotated at a speed of 100 rpm to 2000 rpm. The method according to claim 1,
The friction stirrer includes:
A body part,
And a high-speed rotation tool protruding from the body part to be inserted into the plate,
Wherein the depth of insertion of the high-speed rotation tool is in the range of 10 탆 to 10 mm. A surface strengthening mold formed by the surface strengthening method of claim 1. 15. The method of claim 14,
Wherein the modifying portion is formed in a range of 20 to 20 mm on one surface of the plate. A surface strengthening sheet formed by the surface strengthening method of claim 1.

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