KR20140131596A - Void-formation method - Google Patents

Abstract

Provided is a rotation tool and a method of forming an air gap for forming voids which are less liable to collapse when the gap is formed inside the metal member by friction stir, and surface defects are less likely to occur. (1) for forming an air gap (M) inside a metal member (Z) while rotating the metal member (Z) while rotating the shoulder portion (2) Wherein a value obtained by dividing the outer diameter of the shoulder portion by the outer diameter of the tip of the agitating fin is 1.4 or more and 2.2 or less and the agitating fin 3 is vertically lowered from the stirring pin 3, Or less.

Description

Void formation method (VOID-FORMATION METHOD)

TECHNICAL FIELD The present invention relates to a rotating tool for forming voids that forms voids inside a metal member by friction stir, and a void forming method using the same.

Patent Document 1 discloses a tool for forming voids having a shoulder portion and a stirring pin vertically lowered on the bottom surface of the shoulder portion. On the outer peripheral surface of the stirring pin, screw grooves are formed. When the gap is formed inside the metal member, the rotating tool for forming voids, which is rotated in the retreating direction of the thread groove, is pressed into the surface of the flat metal member and moved relative to the metal member while maintaining the constant height . As a result, the plasticized fluidized metal is pushed to the vicinity of the bottom surface of the shoulder portion by the helical induction of the thread groove, and a part of the burnt metal is pressed by the bottom surface of the shoulder portion. Therefore, since the upper portion of the gap is covered with the metal member that has been plasticized by the friction stir, tunnel-like voids can be formed inside the metal member.

Japanese Laid-Open Patent Application No. 11-47961

However, depending on the configuration of the rotating tool for forming cavities, there is a possibility that the cavities may be crushed or holes (hereinafter also referred to as " surface defects ") may be caused to communicate with the surfaces of the cavities.

In view of the above, it is an object of the present invention to provide a method of forming a cavity and a rotary tool for forming voids in which voids are hardly crushed and surface defects are less likely to occur when cavities are formed in metal members by friction stir We will do it.

The present invention for solving such problems is a gap forming method for forming a gap in a metal member by using a rotating tool for forming voids, wherein the rotating tool for forming voids includes a shoulder portion and a shoulder portion vertically lowered Wherein a spiral groove is formed on the outer circumferential surface of the stirring pin and the spiral groove is formed so as to make a right rotation from the upper side to the lower side, and a value obtained by dividing the outer diameter of the shoulder portion by the outer diameter of the tip of the stirring pin 1.4 or more and 2.2 or less and an angle of the spiral groove with respect to a reference plane having a normal to the axial direction of the stirring pin is set to 20 degrees or more and 40 degrees or less, The distance between the surface of the metal member and the bottom surface of the shoulder portion is set to 0 to 3.0 mm, The metal fluidized by the friction stir is scraped to the surface side of the metal member by the helical groove and pressed by the bottom surface of the shoulder portion while turning the tool from the upper side to the right.

Further, the present invention is a gap forming method for forming a gap in a metal member by using a rotating tool for forming voids, wherein the rotating tool for forming voids has a shoulder portion and a stirring pin vertically lowered at the shoulder portion A spiral groove is formed on the outer circumferential surface of the stirring pin such that the spiral groove is turned counterclockwise from the upper side to the lower side and a value obtained by dividing the outer diameter of the shoulder portion by the outer diameter of the tip of the stirring pin is 1.4 to 2.2 And an angle of the spiral groove with respect to a reference plane having a normal to the axial direction of the agitating pin is set to be not less than 20 degrees and not more than 40 degrees and the rotating tool for forming voids is moved relative to the metal member The distance between the surface of the metal member and the bottom surface of the shoulder portion is set to 0 to 3.0 mm and the gap forming rotary tool is viewed from above While rotating, the metal-backed by friction agitation, it was raised by the helical groove to scrape the side of the surface of the metal member, characterized in that which is pressed by the bottom surface of the shoulder portion.

According to such a constitution, since the plastically fluidized metal can be adequately pushed out and the burnt metal can be pushed to the bottom surface of the shoulder portion, the pores are hard to crumble and surface defects are hardly caused in the metal member. If the value obtained by dividing the outer diameter of the shoulder portion by the outer diameter of the tip of the agitating fin is less than 1.4, the burnt metal is not pressed against the bottom surface of the shoulder portion, and surface defects are likely to occur. On the other hand, if the value obtained by dividing the outer diameter of the shoulder portion by the outer diameter of the tip of the stirring pin is set to be larger than 2.2, the metal is hard to be pushed in the shoulder portion, so that the pores in the metal member are liable to be crushed. In addition, the load applied to the main shaft motor of the friction stir device increases.

Further, it is preferable that the angle of the spiral groove with respect to the reference plane whose axis is the axial direction of the stirring pin is set to 20 degrees or more and 40 degrees or less. According to this configuration, the pores are harder to collapse. If the angle of the helical groove with respect to the reference plane is less than 20 degrees, the angle is shallow, so that the metal is hard to be pierced in the shoulder portion. Further, if the angle of the helical groove with respect to the reference plane is set to be larger than 40 degrees, the spiral groove length with respect to the agitating pin is shortened, so that the metal is hard to be buried in the shoulder portion. Therefore, in any case, there is a possibility that the pores are collapsed.

It is also preferable that the spiral groove is wound on the outer circumferential surface of the stirring pin for at least one week. If the number of turns of the helical groove is less than one week, there is a possibility that the plasticized fluidized metal remains on one of the side walls of the gap and the gap is crushed. However, according to this configuration, since the metal is plasticized and fluidized in a well- Can be avoided.

Preferably, the spiral groove portion in which the helical groove is formed and the flat surface portion in which the helical groove is not formed are formed in the stirring pin, and the helical groove portion is formed from the tip of the stirring pin. According to this configuration, a gap can be formed at a deep position of the metal member.

Preferably, a protrusion is provided on the bottom surface of the shoulder portion and the protrusion is formed in a spiral shape around the stirring pin. According to this constitution, the formed voids become a relatively ordered shape.

It is preferable that the protrusion is formed with a notch cut in the radial direction of the bottom surface of the shoulder. According to this configuration, the plasticized fluidized metal tends to collect around the proximal end portion of the stirring pin, and the metal tends to be pushed out from the cutout portion. Thereby, a comparatively large gap can be formed.

It is preferable that the stirring pin is formed to have a constant outer diameter from the tip end to the base end. According to this configuration, the width of the gap can be made constant.

According to such a method, a relatively large gap can be formed. When the bottom surface of the shoulder portion is press-fitted below the surface of the metal member, the plastically fluidized metal is harder to bite, so that the pores are prone to collapse. On the other hand, if the distance between the surface of the metal member and the bottom surface of the shoulder portion is larger than 3.0 mm, the burnt metal is not pressed against the bottom surface of the shoulder portion, and surface defects easily occur in the metal member. The " surface " of the metal member here refers to the surface of the metal member before friction stir.

According to the rotation tool for forming cavities and the method of forming voids according to the present invention, voids are hardly crushed and surface defects on the metal member are less likely to occur when cavities are formed in the metal members by friction stir.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a side view and a bottom view of a tool for forming voids according to an embodiment of the present invention. FIG.
Fig. 2 is a diagram showing a void forming method according to the present embodiment, wherein (a) is a side sectional view and (b) is a II vertical cross-sectional view of (a).
Fig. 3 (a) is a side view showing a first modified example, and Fig. 3 (b) is a bottom view of a shoulder portion showing a second modified example.
4 is a side view showing the third modification.
5 (a) shows a side view and a bottom view of a tool NO.S1, (b) shows a tool NO.S2, and FIG. 5 (c) shows a side view and a bottom view of a tool NO.S3 .
Fig. 6 is a plan view of a metal member showing a test result of a spiral groove angle test, in which (a) shows the result of the tool No. S. 1, (b) shows the result of the tool No. S. 2, Results are shown.
6 (b) is a cross-sectional view taken along the line II-II in Fig. 6 (b), and Fig. 7 (c) Sectional view.
8 is a graph showing the relationship between the air gap area and the clearance in the spiral groove angle test for each tool.
9 is a graph showing the relationship between the air gap area and the clearance in the spiral groove angle test by the moving speed.
Fig. 10 is a graph showing the relationship between the pore area and the moving speed in the spiral groove angle test by gap.
Fig. 11 shows a tool for rotating a tool for forming an air gap used in the shoulder portion outer diameter test. Fig. 11 (a) shows the tool number T.T, (b) shows the tool number.T2, .
Fig. 12 is a plan view of a metal member showing a test result of a shoulder portion outer diameter test. Fig. 12 (a) shows the result of the tool No. T1, Results are shown.
Fig. 13 is a sectional view taken along line III-III of Fig. 12 (a), Fig. 13 (b) is a sectional view taken along the line III- to be.
14 is a graph showing the relationship between the air gap area and the clearance in the outer diameter test of the shoulder portion for each tool.
15 is a graph showing the relationship between the air gap area and the clearance in the outer diameter test of the shoulder portion for each tool.
Fig. 16 is a graph showing the relationship between the clearance area in the shoulder portion outer diameter test and the outer diameter of the shoulder portion by clearance.
Fig. 17 is a graph showing the relationship between the clearance area in the shoulder portion outer diameter test and the outer diameter of the shoulder portion by clearance.
Fig. 18 is a rotation tool for forming voids used in the ridge test. Fig. 18A is a side view of the tool Nos. 3-1 to 3-3, Fig. Fig.
Fig. 19 is a cross-sectional view of a metal member showing a test result of the ruggedness test. Fig. 19 (a) shows the results of tool Nos. The results of S3-3 are shown.
20 is a graph showing the relationship between the gap area and the clearance in the roughness test for each tool.
Fig. 21 is a rotation tool for forming voids used in an agitating pin outer diameter test. Fig. 21 (a) shows the tool No.U1, (b) shows the tool No.U2, (c) shows the tool No.U3, and Fig. Side view and a bottom view of U4.
Fig. 22 is a cross-sectional view showing a test result of the stirring pin outer diameter test. Fig. 22A shows the result of the tool NO.U1, Fig. 22B shows the result of the tool NO.U2, d) shows the result of tool NO. U4.
23 is a graph showing the relationship between the pore area and the clearance in the stirring pin outer diameter test for each tool.
24 is a graph showing the relationship between the pore area and the clearance in the stirring pin outer diameter test for each tool.
25 is a graph showing the relationship between the pore area in the stirring pin outer diameter test and the outer diameter of the stirring pin by clearance.
Fig. 26 is a rotation tool for forming voids used in the cavity depth test. Fig. 26 (a) shows the tool No. T2, Fig. 26 (b) / RTI >
Fig. 27 is a cross-sectional view showing a test result of the pore depth test, (a) and (b) show the results of tool No. T2, and Figs.
Fig. 28 is a sectional view showing the test result of the cavity depth test, and Figs. 28A and 28B show the results of the tool Nos. T.2-2.
FIG. 29 is a graph showing the relationship between the gap depth and the height of the flat surface portion in the cavity depth test on a clearance basis. FIG.
30 is a graph showing the relationship between the gap depth in the cavity depth test and the height of the flat surface portion by gap.
31 is a graph showing the relationship between the air gap area and the gap in the cavity depth test by the height of the spiral groove portion.
32 is a graph showing the relationship between the pore area and the gap in the pore depth test by the height of the spiral groove portion.
Fig. 33 is a table showing the states of the gaps formed with the respective tools in the embodiment. Fig.
Fig. 34 is a table showing the state of each tool and voids formed in the embodiment. Fig.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail with reference to the drawings. As shown in Fig. 1, the cavity forming rotary tool 1 according to the present embodiment has a shoulder portion 2 and a stirring pin 3. The cavity forming rotary tool 1 is formed of, for example, a tool steel or the like. The cavity forming rotary tool 1 is a tool for forming tunnel-like voids inside a metal member by rotating while moving in a metal member. For example, a metal member can be used as a cooling plate by flowing a fluid such as a gas or a liquid to a tunnel-shaped gap formed by the tool.

The shoulder portion 2 has a cylindrical shape and is connected to a friction stir device (not shown). On the bottom surface 2a of the shoulder portion 2, a ridge 2b is formed. As shown in Fig. 1 (b), the projections 2b are formed in the shape of a spiral around the agitating fin 3. The cross-sectional shape of the ridge 2b is not particularly limited, but it is rectangular in the present embodiment. Although the number of times of winding of the protrusion 2b is not particularly limited, in the present embodiment, the winding is wound for about one and a half weeks or more. By providing the ridges 2b, the plasticized material (base material) is liable to flow around the proximal end side of the agitating fin 3 at the time of friction stir.

(The distance P1 from the proximal end of the agitating fin 3 to the start position of the protuberance 2b) and the scroll pitch of the protuberance 2b (the distance P2 between the protuberances 2b) Is not particularly limited and may be appropriately set. The ridge 2b may not be provided.

The stirring pin 3 is concentric with the shoulder portion 2 and is vertically lowered to the bottom surface 2a of the shoulder portion 2. Further, the stirring pin 3 has a thinner end in the present embodiment. The length of the agitating pin 3 is not particularly limited and may be suitably set.

In the present embodiment, the outer diameter X1 of the shoulder portion 2 and the outer diameter Y2 of the tip end of the stirring pin 3 are set so that X1 / Y2 = 1.4 to 2.2. In this case, when the gap is formed in the metal member by the friction stir, it is difficult for the gap to be crushed and surface defects are hardly caused in the metal member. In addition, the load imposed on the friction stir device can be reduced. The grounds are as follows.

A spiral groove 3a is formed on the outer peripheral surface of the stirring pin 3 from the tip end of the stirring pin 3 to the base end. In the present embodiment, the helical groove 3a is formed by grooving with a ball end mill. The cross-sectional shape of the helical groove 3a is not particularly limited, but is semicircular in the present embodiment. In this embodiment, the helical groove 3a is formed as a right turn (right screw) when it goes from downward to downward.

The angle (lead angle)? Of the helical groove 3a with respect to the reference plane having the axial direction of the agitating pin 3 as a normal is preferably set appropriately between 20 and 40 degrees. If the angle alpha of the helical groove 3a is less than 20 degrees, the angle is too shallow so that the plasticized metal from the shoulder portion 2 is hard to be buried. On the other hand, if the angle? Of the spiral groove 3a is larger than 40 degrees, the length of the spiral groove 3a with respect to the stirring pin 3 is shortened, so that the metal which has been plastically fluidized from the shoulder portion 2 Loses. Therefore, in any case, the voids tend to collapse.

The number of turns of the helical groove 3a in the axial direction is not particularly limited, but is preferably at least one turn or more. If it is wrapped around for more than one week, it can form a large gap. If the number of turns of the spiral groove 3a is less than one week, the position of the spiral groove 3a with respect to the stirring pin 3 is biased, and therefore the possibility that the plasticized metal remains in either side wall of the gap .

The spiral groove 3a is configured as described above in the present embodiment, but it may be formed in a left turn when it is strolled downward from above (left screw).

Next, the void forming method according to the present embodiment will be described. As shown in Fig. 2, the present embodiment exemplifies the case of machining a flat metal member Z. Fig. The material of the metal member Z is not particularly limited, but may be selected from metals capable of friction stirrer such as aluminum, aluminum alloy, copper, copper alloy, titanium, titanium alloy, magnesium, and magnesium alloy.

The rotating tool 1 for forming voids is rotated above the metal member Z so that the stirring pin 3 is pressed into the surface Za of the metal member Z and held at a constant height, Z) relative to the rotating tool 1 for forming voids. The rotating speed of the rotating tool 1 for forming voids is not particularly limited, but is set between 700 and 1300 RPM, for example. The moving speed of the rotating tool 1 for forming voids is set to, for example, 200 to 400 mm / min. The bottom surface 2a of the shoulder portion 2 and the surface Za of the metal member Z may be moved in contact with each other or may be moved with a gap therebetween. The distance (distance) K between the bottom surface 2a of the shoulder portion 2 and the surface Za of the metal member Z may be appropriately set between 0 and 3.0 mm, for example.

As shown in Fig. 2A, in the present embodiment, since the spiral groove 3a is formed at the right turn from the upper side toward the lower side, in the void forming method, Thereby rotating the rotating tool 1. That is, the void forming rotary tool 1 is rotated and moved in the direction in which the metal plastified and fluidized by the helical groove 3a is scratched on the surface Za of the metal member Z.

In addition, in the case where the helical groove 3a is formed in a left-turning direction from the upper side to the lower side, the plasticized fluidized metal can be wound around the surface Za of the metal member Z, The rotary tool 1 for use is rotated.

In the void forming method, the metal member Z is frictionally agitated by the void forming rotary tool 1, and the upward flow of plastic is generated by the helical groove 3a. Thereby, the fluidized metal is guided to the spiral groove 3a and is spread toward the surface Za side of the metal member Z. The burnt metal is pressed by the urging force of the cavity forming rotary tool 1 while being in contact with the bottom surface 2a. A tunnel-like void M formed by the metal being spread is formed in the trace passing through the gap forming rotary tool 1, and a plasticizing zone Z2 is formed on the gap M.

2 (b), the metal member Z after the friction stir has the main body Z1, the gap M formed inside the main body Z1, the gap M, And a plasticizing zone Z2 covering the upper portion of the mold. The plasticizing zone Z2 is a portion formed by hardening after the metal is plastic-fluidized by friction stir. In the present embodiment, the plasticizing zone Z2 is formed so as to cover the upper side of the gap M with a cross-sectional trapezoidal shape. The plasticizing zone Z2 is formed by pressing the metal frictionally agitated by the stirring pin 3 by the bottom surface 2a of the shoulder 2. [ The metal overflowing from the bottom surface 2a of the shoulder portion 2 becomes burr V and is exposed on the surface Za. The burr V is preferably removed by cutting or the like.

In the present embodiment, the air gap M is formed in a substantially rectangular shape when cross sectioned. The space M is a closed space in the present embodiment and is a space communicating with the space M in the interior of the plasticizing zone Z2 or the boundary between the main body Z1 and the plasticizing zone Z2 No surface defects are formed. The distance from the upper end of the gap M to the surface Za is referred to as " gap depth D ".

Depending on the shape of the rotating tool 1 for forming voids, there is a possibility that the metal is not adequately crowded and the void M is crushed. On the other hand, when the metal is excessively sputtered, the plasticizing zone Z2 becomes thin, and the inside of the plasticizing zone Z2 and the space M between the main body Z1 and the plasticizing zone Z2 are communicated There is a possibility that surface defects are formed.

However, according to the rotating tool 1 for forming voids, the metal can be adequately pushed out and the burnt metal can be pressed against the bottom surface 2a of the shoulder portion 2, so that the gap M is hard to crush, Further, surface defects are unlikely to occur in the metal member (Z). In addition, the load imposed on the friction stir device can be reduced. The conditions such as the ratio of the outer diameter X1 of the shoulder portion 2 to the outer diameter Y2 of the front end of the stirring pin 2 and the numerical value of the angle alpha of the helical groove will be described in the embodiment.

Further, since the agitating fin 3 according to the present embodiment has a tapered shape, it is possible to reduce the push-in resistance at the time of press fitting into the metal member (Z).

<First Modification>

Next, a first modification of the present invention will be described. The void forming rotary tool 1A according to the first modification is different from the above-described embodiment in that the stirring pin 3 is provided with the flat surface portion 11 and the helical groove portion 12.

3 (a), on the outer peripheral surface of the agitating fin 3 according to the first modified example, a flat surface portion 11 in which no grooves are formed and a helical groove portion in which a helical groove 3a is formed 12). The outer peripheral surface of the flat surface portion 11 is flat and is formed from the proximal end of the stirring pin 3 to the substantially central portion of the stirring pin 3.

On the other hand, on the outer circumferential surface of the helical groove portion 12, a helical groove 3a is formed from the tip to substantially the center (from the flat surface portion 11). It is preferable that the helical groove 3a is rolled at least one week or more. The height H1 of the helical groove portion 12 may be appropriately set in accordance with the depth of the gap M to be formed with respect to the metal member Z. For example, (The height of the flat surface portion 11 is 70% to 30% of the length of the agitating fin 3) with respect to the length of the stirring pin 3.

Since the spiral groove 3a is formed from the tip end of the stirring pin 3 to the proximal end portion of the rotating tool 1 for forming voids shown in Fig. 1, the metal tends to be relatively easily pushed out, Tends to be shallow.

However, according to the rotation tool 1A for forming voids according to the first modified example, the metal is pushed by the helical groove portion 12 to form the gap M, but the metal, which is frictionally stirred by the flat surface portion 11, It is difficult to be pushed out from the part (2). Therefore, since the thickness of the plasticizing zone Z2 is increased, the gap depth D can be increased (deepened). As a result, a large gap M can be formed at a deep position of the metal member Z, and at the same time, inside the plasticizing zone Z2 or at the boundary between the main body Z1 and the plasticizing zone Z2 Surface defects are more difficult to form.

&Lt; Second Modified Example &

Next, a second modification of the present invention will be described. 3 (b), in the cavity forming rotary tool 1B according to the second modification, a ridge 2b formed on the bottom surface 2a of the shoulder portion 2 is intermittently formed Which is different from the above-described embodiment.

The ridge 2b according to the second modification has a plurality of cutouts 2c for dividing the ridge 2. [ The metal that has been plastically fluidized in the radial direction of the bottom surface 2a of the shoulder portion 2 is liable to flow because the plastically fluidized metal passes through the cutout portion 2c by providing the cutout portion 2c. As a result, the metal tends to collect around the proximal end portion of the agitating fin 3, and the plastically fluidized metal from the notch portion 2c tends to be buried. Thus, a relatively large gap M can be formed. The number and size of the cutouts 2c may be set appropriately.

&Lt; Third Modified Example &

Next, a third modification of the present invention will be described. As shown in Fig. 4, the gap forming rotation tool 1C according to the third modification is different from the above-described embodiment in that the outer diameter of the agitating fin 3 is constant.

The outer diameter Y1 of the base end portion of the stirring pin 3 of the void forming rotary tool 1C is equal to the outer diameter Y2 of the tip end. The outer diameter of the stirring pin 3 may be made constant. Thereby, the void M formed by the void forming method can be formed with a constant width.

Although the embodiments and the modifications of the present invention have been described above, it is possible to appropriately change the design within the scope of the present invention.

Example

<Test Overview>

Next, an embodiment of the present invention will be described. In the examples, the voids were formed by changing the shapes, sizes, ratios, and the like of the respective elements constituting the void forming rotary tool, and the formed voids were observed. For the sake of convenience of explanation, the void forming rotary tool is hereinafter also simply referred to as a &quot; tool &quot;.

In the examples, five kinds of tests were roughly divided. A "spiral groove angle test" for examining the influence of the angle of the spiral groove of the tool (lead angle), a "shoulder portion outer diameter test" for examining the influence of the outer diameter of the shoulder portion, "Stirring pin outer diameter test" for examining the influence of the outer diameter of the stirring pin, and "pore depth test" for examining the pore depth of the formed firing area.

For the pore depth test, an A1050 alloy plate was used, and for the other tests, an A1100 alloy plate was used. The cross-sectional shape of the helical groove formed in the agitating pin is semicircular, and its radius is 1.5 mm. The starting position (distance P1 in Fig. 1 (b)) of the protrusion was 3.0 mm, and the scroll pitch (distance P2 in Fig. 1 (b)) was 2.5 mm.

In the void formation method, a tool rotated on the alloy plate was press-fitted and moved a predetermined distance. The number of revolutions of the tool was set to 800 RPM, and in the cavity depth test, friction stir was performed at 1275 RPM to investigate the influence of the number of revolutions of the tool.

The moving speed of the tool was 100 mm / min or 300 mm / min. In the spiral groove angle test, the influence of the moving speed was also investigated by changing the moving speed between 50 and 300 mm / min.

In each test, the clearance (distance K in FIG. 2A) between the surface of the metal member and the bottom of the shoulder was changed to 0 mm, 1.0 mm, 2.0 mm and 3.0 mm, Frictional agitation was performed on the members to compare the voids formed respectively. In either alloy plate (test body), the central portion of the alloy plate was cut, polished and etched, and then the shape of the formed voids was observed. Further, the cross-sectional area of the gap formed by using the image device was measured.

&Lt; Spiral groove angle test &

In the spiral groove angle test, the influence of the angle of the spiral groove 3a of the stirring pin 3 was examined. As shown in Fig. 5, three kinds of tools NO.S1 to S3 were used in this test. The angle with the horizontal plane of the helical groove 3a was set at 40 degrees in the tool Nos. 1, 30 degrees in the tool Nos. 2, and 20 degrees in the tool Nos. 3. The number of turns of the stirring pin 3 in the axial direction of the spiral groove of each tool is about 0.8 week for tool No. S .1, about 1.3 weeks for tool No. S .2, and about 2.3 for tool No. S. .

The outer diameter of the shoulder portion 2 is 22 mm, the outer diameter of the base end portion of the stirring pin 3 is 10 mm, the outer diameter of the tip end is 7 mm, The length of the pin 3 was set to 11 mm. In addition, in any tool, the bottom surface 2a of the shoulder portion 2 is provided with a spiral-shaped ridge 2b. The height of the ridge 2b was 1 mm.

Fig. 6 is a plan view of the metal member showing the test result of the helical groove angle test. Fig. 6 (a) shows the result of the tool No. S. 1, Fig. All of the plasticizing zones Z2 are formed on the surface Za of the metal member Z (main body Z1) in Figs. 6A, 6B and 6C. The plasticizing zone Z2 is set to 2.0 when the clearance between the surface Za of the metal member Z and the bottom surface 2a of the shoulder portion 2 is 0 mm, And the case of 3.0 mm is shown in the case of mm.

6 (b) is a sectional view taken along the line II-II in FIG. 6 (b), and FIG. 6 (c) is a sectional view taken along the line II- Sectional view.

6 (a) to 6 (c), the entire surface of the bottom surface 2a of the shoulder portion 2 is brought into contact with the plasticized fluidized metal under the conditions of 0 mm and 1.0 mm of clearance, V) are generated. At the gap of 2.0 mm, the entire surface of the bottom surface 2a of the shoulder portion 2 was in contact with the plasticized fluidized metal, but the burr V was relatively small. At the gap of 3.0 mm, the width of the plasticizing zone Z2 formed by plasticizing and fluidizing was shorter than the outer diameter X1 of the shoulder 2 (see Fig. 1 (a)).

6 and 7, the side to which the moving speed of the tool is added to the rotational speed of the tool is referred to as &quot; Advancing side &quot; (hereinafter also referred to as &quot; Ad side &quot;), The side on which the speed is subtracted is called a &quot; retreating side &quot; (hereinafter, also referred to as &quot; Re side &quot;). In the present embodiment, since the tool is moved from the left side to the right side in Fig. 6 while being rotated to the right, the left side in the advancing direction is the Ad side and the right side is the Re side.

As shown in Fig. 7 (a), the gap M in the tool Nos. 1 has a rectangular and elongated rectangular shape. The plasticizing zone Z2 covers the space M, but a part of the plasticizing zone Z2 remains on the sidewall of the Re side of the cavity M. [

On the other hand, under the conditions of the tool No. S 2. and the tool No. S 3, the gap M of approximately the same shape is formed under the condition of the gap of 1.0 to 3.0, and the sintered fluidized metal does not remain on the sidewall of the gap M , And is discharged to the outside.

In the tools Nos. 1 to S3, it has been found that as the gap increases, the height position of the gap M moves to the upper side of the metal member Z and the height of the gap M increases. As the gap between the tools NO.S1 to S3 increases, the sectional area of the plasticizing zone Z2 becomes smaller and the gap depth D from the upper end of the gap M to the surface Za of the metal member Z ) Becomes smaller.

In tool NO.S2 and tool NO.S3, the width of the gap M formed and the outer diameter of the front end of the stirring pin 2 were substantially equal to each other. However, in tool NO.S1, ). As shown in Fig. 7 (a), a part of the plasticizing zone Z2 remains on the sidewall on the Re side of the gap M. Fig. This is believed to be attributable to the angle of the spiral groove 3a of the NO.S1 tool and the number of turns.

In the tool Nos. 1, since the angle of the helical groove 3a is 40 degrees, the length of the helical groove with respect to the agitating pin 3 is short. Therefore, it is considered that the plasticized fluidized metal is difficult to discharge. In Tool No. 1, since the number of turns of the spiral groove 3a is less than one week, the position of the spiral groove 3a with respect to the stirring pin 3 is shifted. As a result, it is considered that the fired metal remains on one sidewall (here, Re side) of the formed void M.

Fig. 8 is a graph showing the relationship between the gap area and the clearance in the spiral groove angle test on a tool-by-tool basis. As shown in Figs. 7 and 8, the pore area of the gap M formed by the tool NO.S2 and the tool NO.S3 was substantially the same, but the pore area obtained by the tool NO.S1 was smaller than that of the tool NO.S2 And tool NO.S3.

Further, as shown in Fig. 8, as the gap increases from tool Nos. 1 to S3, the void area (cross-sectional area of the gap M) increases. As a result, it has been found that if the tool is separated from the metal member Z and the plastically fluidized metal is easy to be poured, the void area of the void M can be increased. The rate of increase in the pore area (slope of the graph) of the tool Nos. S 1 to S 3 was about 7 mm 2 / mm and almost equal to the outer diameter of the tip of the agitating fin 3.

9 is a graph showing the relationship between the air gap area and the clearance in the spiral groove angle test by the moving speed. Since the tools NO.S1 to S3 have almost the same results, FIG. 9 shows the result of the tool NO.S2 as a representative example.

Fig. 10 is a graph showing the relationship between the air gap area and the moving speed in the spiral groove angle test by gap. Fig. 10 shows the relationship between the pore area and the moving speed obtained by the tool NO.S3.

As is clear from Figs. 9 and 10, it was found that the pore area was not significantly influenced by the change of the moving speed.

<Shoulder portion outer diameter test>

In the outer diameter test of the shoulder portion, the influence of the outer diameter of the shoulder portion 2 was examined. As shown in Fig. 11, three kinds of tools Nos. 1 to 3 are used in this test. The outer diameter of the shoulder portion 2 was set at 20 mm in the tool No. T 1, 18 mm in the tool No. T 2, and 16 mm in the tool No. T 3. The configuration except for the outer diameter of the shoulder portion 2 is the same for all three types. The outer diameter of the proximal end of the stirring pin 3 is 10 mm, the outer diameter of the distal end is 7 mm, and the length of the stirring pin 3 is set to 11 mm did. In addition, in any tool, the bottom surface 2a of the shoulder portion 2 is provided with a spiral-shaped ridge 2b. The height of the ridge 2b was 1 mm.

Fig. 12 is a plan view of a metal member showing a test result of the outer diameter test of the shoulder portion. Fig. 12 (a) is a result of the tool number T.T1, (b) is the result of the tool number.T2, Fig. 12 (b) is a cross-sectional view taken along the line III-III of FIG. 12 (b), and FIG. 12 (c) is a cross- III sectional view. As shown in Fig. 5 (c), the tool No. S. 3 described above has an outer diameter of 22 mm of the shoulder portion 2 and the other configurations are equal to the tools Nos. T 1 to T 3, (c) and Fig. 7 (c).

It was found that even though the clearance was 2.0 mm, the plasticized fluidized metal contacted the bottom surface 2a of the shoulder portion 2 and the burr V was largely discharged from the Re side by reducing the outer diameter of the shoulder portion 2. At the gap of 3.0 mm, the burr (V) was discharged to the Re side, but the surface defect E communicating with the gap M due to the shortage of metal in the tool NO.T1 and the metalization area Z2 in the tool NO.T3 .

On the other hand, as the outer diameter of the shoulder portion 2 becomes smaller, the height of the gap M increases. By reducing the outer diameter of the shoulder portion 2, the amount of metal that can be restrained by the bottom surface 2a of the shoulder portion 2 is reduced. As a result, it is considered that the plasticized fluidized metal is liable to be buried and the height of the gap M is increased.

Figs. 14 and 15 are graphs showing the relationship between the air gap area and the clearance in the shoulder portion outer diameter test for each tool. Fig. 14 is a graph showing a moving speed of 100 mm / min, min. &lt; / RTI &gt;

As shown in Figs. 14 and 15, as the gap increases in all the tools, the pore area increases. As a result, it has been found that if the tool is separated from the metal member Z and the plastically fluidized metal is easy to be poured, the void area of the void M can be increased. The increment ratio (slope of increase) of the pore area of the tool NO.S3 and the tools NO.T1 to T3 was about 7 mm2 / mm and was equal to the outer diameter of the tip of the agitating pin 3. [

16 and 17 are graphs showing the relationship between the air gap area in the shoulder portion outer diameter test and the outer diameter of the shoulder portion by the clearances in FIG. 16, the moving speed is 100 mm / min, the moving speed is 300 Mm / min. &Lt; / RTI &gt;

As shown in Figs. 16 and 17, when the gap is 2.0 mm, the gap area obtained by the outer diameter of the shoulder portion 2 of 22 mm and the gap area obtained by the outer diameter of the shoulder portion 2 of 20 mm are almost equal to each other Equal. As the outer diameter of the shoulder portion 2 was reduced in the range of the outer diameter of the shoulder portion 2 from 20 mm to 16 mm, the void area increased. The rate of increase of the pore area (slope of the increase) was about 5 mm 2 / mm.

As shown in Fig. 16, under the condition that the moving speed is 100 mm / min and the clearance is 3.0 mm, as the outer diameter of the shoulder portion 2 becomes smaller in the range of the outer diameter of the shoulder portion 2 from 22 mm to 16 mm , The pore area increased linearly. This is considered to be because the pressure from the shoulder portion 2 decreases as the outer diameter of the shoulder portion 2 becomes smaller and the amount of discharged metal increases.

On the other hand, as shown in Fig. 17, under the condition that the moving speed is 300 mm / min and the gap is 3.0 mm, surface defects have occurred in the plasticizing region at the outer diameter of 16 mm and 18 mm of the shoulder portion 2 The pore area decreased.

<Rolling test>

In the ruggedness test, the influence of the rug 2b formed on the bottom surface 2a of the shoulder portion 2 was examined. As shown in Fig. 18, in this test, three types of rotating tool tools NO.S3-1 to S3-3 for forming voids were used. The width of the notch 2c of the ridge 2b was set to 2 mm in the tool Nos. 3-1 and 6 mm in the tool Nos. 3-2. No tools were installed in Tool No. S.3-3. The outer diameter of the shoulder portion 2 is 22 mm, the outer diameter of the base end portion of the stirring pin 3 is 10 mm, the outer diameter of the tip end is 7 mm, the length of the stirring pin 2 Was set at 11 mm.

Fig. 19 is a cross-sectional view of a metal member showing a test result of a rugged test. Fig. 19 (a) shows the results of tool Nos. . The results of .S3-3 are shown. 20 is a graph showing the relationship between the gap area and the clearance in the roughness test for each tool. As shown in Fig. 5C, the void forming rotary tool NO.S3 described above is provided with the ridge 2b without the cutout 2c, and the other configuration is the tool NO.S3 -1 to S3-3. Therefore, consideration will be given to both FIGS. 6 (c) and 7 (c).

As shown in Figs. 7 (c), 19 (a) and 20, the pore areas of the tool No. 3, the tool No. 3-1, and the tool No. 3-3 were substantially equal. When the result of Tool No. 3 is compared with the result of Tool No. 3 - 3, it is found that there is no influence on the result of the void area in the presence or absence of the ridge 2b. However, in contrast to FIG. 7 (c) and FIG. 19 (c), it has been found that the shape of the gap M of the tool No. 3 having the protuberance 2b is adjusted. This is thought to be due to the fact that the plastically fluidized metal tends to collect around the proximal end side of the agitating fin 3 because there is the ridge 2b.

As in Tool No. 3-2, if the length of the notch portion 2c is 6 mm and the length is relatively large, the pore area is also large. This is considered to be due to the fact that the plasticized fluidized metal is liable to flow in the radial direction of the bottom surface 2a of the shoulder portion 2 and the metal tends to be pushed out if the length of the notch portion 2c is large.

&Lt; Stirring pin outer diameter test &

In the stirring pin outer diameter test, the shoulder portion 2 having the same outer diameter is used, and the outer diameter of the stirring pin 3 from the proximal end to the distal end is set to be constant, and the outer diameter of each stirring pin 3 is changed, The influence of the outer diameter of the pin 3 was examined. As shown in Fig. 21, in this test, four types of rotating tool tools No. U1 to U4 for forming voids were used. The outer diameter of the agitating pin 3 was set to 10 mm in the tool No. U1, 12 mm in the tool No. U2, 14 mm in the tool No. U3, and 16 mm in the tool No. U4. All of the components other than the outer diameter of the agitating pin 3 were set to be equal to each other, the outer diameter of the shoulder portion 2 was set at 22 mm and the agitating pin 3 was set at 11 mm in length. In addition, in any tool, the bottom surface 2a of the shoulder portion 2 is provided with a spiral-shaped ridge 2b. The height of the ridge 2b was 1 mm.

As shown in Fig. 22 (d), it was found that the surface defect E occurs under the condition of the gap 3.0 mm between the tool No. U4. As shown in Figs. 22 and 23, it has been found that the pore area becomes larger as the gap becomes larger in the tool Nos. U1 to U4. The increase rate of the void area of the tool Nos. U1 to U3 (inclination of the graph) became close to the outer diameter of the agitating pin 3 of each tool.

That is, the rate of increase of the void area of the tool No. U1 (slope of the graph) is 10 mm 2 / mm in FIG. 23, 10.7 mm 2 / mm in FIG. 24, / Mm in Fig. 23, 12.5 mm &lt; 2 &gt; / mm in Fig. 24, and 13.7 mm &lt; 2 &gt; / mm in Fig. 23 and 14.4 mm & This is considered to be because the air gap M is increased by the outer diameter of the agitating fin 3 if the clearance of each tool is increased by 1 mm.

Also, as shown in Figs. 23 and 24, it was found that the difference in the moving speed did not affect the pore area. As shown in Fig. 25, as the outer diameter of the agitating fin 3 increases, the pore area also increases, but the increase tendency is quadratic.

<Void Depth Test>

In the pore depth test, as shown in Fig. 3A, using the pore forming rotary tool having the flat surface portion 11 on which the helical groove 3a is not formed, And the depth position of the test piece was examined. As shown in Fig. 26, in this test, three types of pore forming rotary tools were used. The tool No. T2 is a comparative example and is equivalent to the tool shown in Fig. 11 (b).

As shown in Fig. 27 (a), the height of the spiral groove portion 12 of the tool NO.T2 is equal to the length of the stirring pin 3 and is 11.0 mm. As shown in Fig. 27 (c), the height of the flat surface portion 11 of the tool Nos. 2-1 is 3.5 mm and the height of the helical groove portion 12 is 7.5 mm. As shown in Fig. 28 (a), the height of the flat surface portion 11 of the tool No. T2-2 is 6.0 mm, and the height of the helical groove portion 12 is 5.0 mm.

The outer diameter of the shoulder portion 2 was 18 mm, the outer diameter of the base end portion of the stirring pin 3 was 10 mm, and the outer diameter of the tip end was 7 mm . Both of the tools are provided with a spiral-shaped ridge 2b on the bottom surface 2a of the shoulder portion 2. The height of the ridge 2b was 1 mm. In the pore depth test, three kinds of clearances were defined as 0 mm, 1.0 mm and 2.0 mm from the surface Za of the metal member Z to the bottom surface 2a of the shoulder portion 2. Further, in each tool, the test was performed with two types of revolutions of 800RPM and 1275RPM.

Fig. 27 is a cross-sectional view showing a test result of the cavity depth test, (a) and (b) show the results of the tool No. T2, and (c) and (d) . 28 is a cross-sectional view showing a test result of the cavity depth test, and (a) and (b) show the results of the tool Nos. TW2-2. 29 is a graph showing the relationship between the gap depth in the cavity depth test and the height of the flat surface portion by gap. 30 is a graph showing the relationship between the gap depth in the pore depth test and the height of the flat surface portion by gap. 29 and 30 are different in the number of revolutions of the tool, the number of revolutions of the test in FIG. 29 is 800 RPM, and the number of revolutions of the test in FIG. 30 is 1275 RPM.

As shown in FIGS. 29 and 30, it has been found that the larger the height of the flat surface portion 11 (the length of the stirring pin 3 - the height of the spiral groove portion 12), the larger the gap depth D is. It was also found that the gap depth D becomes larger as the gap becomes smaller. 29 and 30, it is found that the gap depth D becomes slightly larger when the rotation speed of the tool is higher.

31 is a graph showing the relationship between the air gap area and the gap in the cavity depth test by the height of the spiral groove portion. 32 is a graph showing the relationship between the air gap area and the gap in the cavity depth test by the height of the spiral groove portion. 31 and 32 are different in the number of revolutions of the tool, the number of revolutions of the test in FIG. 31 is 800 RPM, and the number of revolutions of the test in FIG. 32 is 1275 RPM.

As shown in Figs. 31 and 32 and Figs. 27 and 28, it was found that the larger the height of the helical groove portion 11, the larger the pore area. 31 and 32, it is found that the number of revolutions of the tool has little influence on the increase or decrease of the pore area.

As described above, according to the gap test, it has been found that the air gap M can be formed at a deep position by increasing the height of the flat surface portion 11. On the other hand, it has been found that if the height of the flat surface portion 11 is excessively increased, the air gap area of the air gap M becomes small.

&Lt; outer diameter of shoulder portion / outer diameter of tip of stirring pin and comparison with test result >

Figs. 33 and 34 are tables showing the states of the gaps formed with the respective tools in the embodiment. Fig. Indicates that the state of the gap M is good, and &quot; x &quot; shows the state in which the surface defect E occurs.

As shown in Figs. 33 and 34, when the value obtained by dividing the outer diameter of the shoulder portion by the outer diameter of the tip of the agitating fin is 1.4 to 2.2, surface defects E do not occur and the state of the gap M is substantially good did. If this value is less than 1.4, the burnt metal can not be pressed against the bottom surface 2a of the shoulder portion 2, and surface defects E are likely to occur. On the other hand, if this value is larger than 2.2, the plastically fluidized metal from the shoulder portion 2 becomes difficult to be buried, so that the pores are prone to collapse. If this value is larger than 2.2, the load on the main shaft motor of the friction stir device becomes large, which is not preferable.

1 Rotary tool for pore formation
2 shoulder part
2a Bottom
2b bump
2c
3 stirring pin
3a Spiral groove
D Cavity depth
K clearance
M air gap
V burr
Z metal member
Z1 body portion
Z2 plasticization zone
Za surface

Claims (7)

A void forming method for forming voids in a metal member by using a rotating tool for forming voids,
Wherein the gap forming rotary tool comprises:
And has a shoulder portion and a stirring pin that vertically descends at the shoulder portion,
A spiral groove is formed on the outer circumferential surface of the stirring pin and the spiral groove is formed so as to make a right turn from the upper side to the lower side,
The angle formed by dividing the outer diameter of the shoulder portion by the outer diameter of the front end of the stirring pin is 1.4 or more and 2.2 or less and the angle of the spiral groove with respect to the reference plane having the axial direction of the stirring pin as a normal, Or less,
Wherein a distance between the surface of the metal member and the bottom surface of the shoulder portion is set to 0 to 3.0 mm when the cavity forming rotary tool is relatively moved with respect to the metal member, Wherein the metal fluidized by the friction stir is scraped to the surface side of the metal member by the spiral groove and is pressed by the bottom surface of the shoulder portion while making a right turn as viewed from the viewpoint of the metal member. A void forming method for forming voids in a metal member by using a rotating tool for forming voids,
Wherein the gap forming rotary tool comprises:
And has a shoulder portion and a stirring pin that vertically descends at the shoulder portion,
A spiral groove is formed on the outer circumferential surface of the stirring pin and the spiral groove is formed so as to make a left turn as it goes downward from above,
The angle formed by dividing the outer diameter of the shoulder portion by the outer diameter of the front end of the stirring pin is 1.4 or more and 2.2 or less and the angle of the spiral groove with respect to the reference plane having the axial direction of the stirring pin as a normal, Or less,
Wherein a distance between the surface of the metal member and the bottom surface of the shoulder portion is set to 0 to 3.0 mm when the cavity forming rotary tool is relatively moved with respect to the metal member, Wherein the metal fluidized by the friction stir is scraped toward the surface side of the metal member by the spiral groove while being pressed by the bottom surface of the shoulder portion while making a left turn as viewed from the side of the metal member. The gap forming method according to claim 1 or 2, wherein the spiral groove is wound on the outer circumferential surface of the stirring pin for one or more turns. The stirring pin according to claim 1 or 2, wherein a helical groove portion in which the helical groove is formed and a flat surface portion in which the helical groove is not formed are formed in the stirring pin,
And the spiral groove portion is formed from the tip end of the stirring pin. The shoulder according to claim 1 or 2, wherein a protrusion is provided on the bottom surface of the shoulder portion,
Characterized in that the ridge is formed in a spiral shape around the stirring pin. 6. The method according to claim 5, characterized in that the protrusions are formed with notches in the radial direction of the bottom surface of the shoulder. The gap forming method according to claim 1 or 2, wherein the stirring pin is formed to have a constant outer diameter from the tip end to the base end.

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