JP6103086B2 - Gap formation method - Google Patents

Description

  The present invention relates to a void forming method for forming a void in a metal member by friction stirring.

  Patent Document 1 describes a gap forming rotary tool including a shoulder portion and a stirring pin suspended from the bottom surface of the shoulder portion. A thread groove is formed on the outer peripheral surface of the stirring pin. When forming a gap inside the metal member, the gap forming rotary tool rotated in the backward direction of the screw groove is pushed into the surface of the flat metal member, and the metal member is kept at a certain height. Move relative to it. As a result, the plastic fluidized metal is scraped to the vicinity of the bottom surface of the shoulder portion by the spiral guidance of the screw groove, and a part of the scraped metal is pressed by the bottom surface of the shoulder portion. Accordingly, since the upper part of the gap is covered with the metal member plasticized by friction stirring, a tunnel-like gap can be formed inside the metal member.

JP 11-47961 A

  However, depending on the configuration of the gap forming rotary tool, the gap may be crushed or a hole communicating with the gap and the surface of the metal member (hereinafter also referred to as “surface defect”) may be formed.

  From such a viewpoint, an object of the present invention is to provide a void forming method in which, when a void is formed in a metal member by friction stirring, the void is hardly crushed and a surface defect is not easily generated.

In order to solve such a problem, the present invention provides a void forming method for forming a void having a substantially rectangular shape in cross section in an aluminum alloy member using a void forming rotary tool, the void forming rotating tool. Has a shoulder portion and a stirring pin hanging from the shoulder portion, and a spiral groove is formed on the outer peripheral surface of the stirring pin so that the spiral groove turns clockwise as it goes from the top to the bottom. The reference plane is set such that a value obtained by dividing the outer diameter of the shoulder portion by the outer diameter of the tip end of the stirring pin is 1.4 or more and 3.1 or less, and the axial direction of the stirring pin is a normal line The angle of the spiral groove with respect to is set to 20 degrees or more and 40 degrees or less, a protrusion is provided on the bottom surface of the shoulder portion, the protrusion is formed in a spiral shape around the stirring pin, and the gap is formed. said the use rotating tool a When moved relative to Miniumu alloy member, characterized in that to clockwise as viewed from above the void-forming rotary tool.
Further, the present invention is a void forming method for forming a void having a substantially rectangular shape in cross section in an aluminum alloy member using a void forming rotary tool, wherein the void forming rotary tool includes a shoulder portion and the shoulder. A stirring pin that hangs down from the portion, and a spiral groove is formed on the outer peripheral surface of the stirring pin, and the spiral groove is formed to turn counterclockwise as it goes downward from above, and the outer diameter of the shoulder portion Is divided by the outer diameter of the tip of the stirring pin to be 1.4 or more and 3.1 or less, and the angle of the spiral groove with respect to a reference plane with the axial direction of the stirring pin as a normal line 20 degrees or more and 40 degrees or less is set, a protrusion is provided on the bottom surface of the shoulder portion, the protrusion is spirally formed around the stirring pin, and the gap forming rotary tool is used as the aluminum alloy. For members The gap forming rotation tool is rotated counterclockwise when viewed from above.

  According to such a configuration, the plastic fluidized metal is suitably scraped, and the scraped metal can be pressed by the bottom surface of the shoulder portion, so that the gap is not easily crushed and surface defects are unlikely to occur in the metal member. . If the value obtained by dividing the outer diameter of the shoulder portion by the outer diameter of the tip end of the stirring pin is less than 1.4, the scraped metal cannot be held by 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 larger than 2.2, it is difficult for the metal to be scraped from the shoulder portion, so that the voids in the metal member are easily crushed. Moreover, the load applied to the spindle motor of the friction stirrer increases. In addition, by forming a protrusion on the bottom surface of the shoulder portion, the formed gap has a relatively well-formed shape.

  Further, it is preferable that the spiral groove is wound around the outer peripheral surface of the agitation pin one or more times. If the winding of the spiral groove is less than one turn, the plasticized metal may remain on one of the side walls of the gap, and the gap may be crushed. Therefore, the gap can be prevented from being crushed.

  Moreover, it is preferable to form the said stirring pin with a fixed outer diameter from the front-end | tip to a base end. According to such a configuration, the width of the gap can be made constant.

  According to the void forming method of the present invention, when the void is formed inside the metal member by frictional stirring, the void is not easily crushed and surface defects are hardly formed on the metal member.

It is a figure which shows the rotation tool for space | gap formation which concerns on this embodiment, Comprising: (a) is a side view, (b) shows a bottom view. It is a figure which shows the space | gap formation method which concerns on this embodiment, Comprising: (a) is a sectional side view, (b) shows the II longitudinal cross-sectional view of (a). (A) is a side view which shows a 1st modification, (b) is a bottom view of the shoulder part which shows a 2nd modification. It is a side view which shows a 3rd modification. It is the rotation tool for void formation used in the spiral groove angle test, (a) shows tool NO.S1, (b) shows tool NO.S2, and (c) shows a side view and a bottom view of tool NO.S3. . It is a top view of the metal member which shows the test result of a spiral groove angle test, (a) is a result of tool NO.S1, (b) is a result of tool NO.S2, (c) is a result of tool NO.S3 Indicates. 6A is a sectional view taken along line II-II in FIG. 6A, FIG. 6B is a sectional view taken along line II-II in FIG. 6B, and FIG. 6C is a sectional view taken along line II-II in FIG. FIG. It is a graph which shows the relationship between the space | gap area and clearance gap in a spiral groove angle test according to a tool. It is a graph which shows the relationship between the space | gap area and clearance gap in a spiral groove angle test according to moving speed. It is a graph which shows the relationship between the space | gap area in a spiral groove angle test, and a moving speed according to a clearance gap. It is the rotation tool for gap formation used in the shoulder part outer diameter test, and (a) is a tool NO.T1, (b) is a tool NO.T2, and (c) is a side view and a bottom view of the tool NO.T3. Show. It is a top view of the metal member which shows the test result of a shoulder part outer diameter test, (a) is the result of tool NO.T1, (b) is the result of tool NO.T2, (c) is the result of tool NO.T3. Results are shown. 12A is a sectional view taken along line III-III in FIG. 12A, FIG. 12B is a sectional view taken along line III-III in FIG. 12B, and FIG. 12C is a sectional view taken along line III-III in FIG. It is. It is a graph which shows the relationship between the space | gap area and clearance gap in a shoulder part outer diameter test according to a tool. It is a graph which shows the relationship between the space | gap area and clearance gap in a shoulder part outer diameter test according to a tool. It is a graph which shows the relationship between the space | gap area in a shoulder part outer diameter test, and the outer diameter of a shoulder part according to a clearance gap. It is a graph which shows the relationship between the space | gap area in a shoulder part outer diameter test, and the outer diameter of a shoulder part according to a clearance gap. It is the rotation tool for gap formation used in the ridge test, where (a) is a tool NO.S3-1, (b) is a tool NO.S3-2, and (c) is a side view of the tool NO.S3-3. And a bottom view. It is sectional drawing of the metal member which shows the test result of a ridge test, Comprising: (a) is a result of tool NO.S3-1, (b) is a result of tool NO.S3-2, (c) is tool NO. The result of S3-3 is shown. It is a graph which shows the relationship between the space | gap area and clearance gap in a protrusion test according to a tool. Rotating tool for forming a gap used in the agitating pin outer diameter test, wherein (a) is tool NO.U1, (b) is tool NO.U2, (c) is tool NO.U3, (d) is tool NO.U3 . Shows side and bottom views of U4. It is sectional drawing which shows the test result of a stirring pin outer diameter test, (a) is a result of tool NO.U1, (b) is a result of tool NO.U2, (c) is a result of tool NO.U3, d) shows the result of tool No. U4. It is a graph which shows the relationship between the space | gap area and clearance gap in a stirring pin outer diameter test according to a tool. It is a graph which shows the relationship between the space | gap area and clearance gap in a stirring pin outer diameter test according to a tool. It is a graph which shows the relationship between the space | gap area in the stirring pin outer diameter test and the outer diameter of a stirring pin according to a clearance gap. The gap forming rotary tool used in the gap depth test, where (a) is a tool NO.T2, (b) is a tool NO.T2-1, (c) is a side view of the tool NOT.T2-2, A bottom view is shown. It is sectional drawing which shows the test result of a space | gap depth test, Comprising: (a) And (b) shows the result of tool NO.T2, (c) And (d) shows the result of tool NO.T2-1. It is sectional drawing which shows the test result of a space | gap depth test, Comprising: (a) And (b) shows the result of tool NO.T2-2. It is the graph which represented the relationship between the space | gap depth and the height of a flat surface part in a space | gap depth test according to the clearance gap. It is the graph which represented the relationship between the space | gap depth and the height of a flat surface part in a space | gap depth test according to the clearance gap. It is the graph which represented the relationship between the space | gap area and clearance gap in a space | gap depth test according to the height of a spiral groove part. It is the graph which represented the relationship between the space | gap area and clearance gap in a space | gap depth test according to the height of a spiral groove part. It is the table | surface showing each tool in the Example, and the condition of the space | gap formed. It is the table | surface showing each tool in the Example, and the condition of the space | gap formed.

  Embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the gap forming rotary tool 1 according to this embodiment includes a shoulder portion 2 and a stirring pin 3. The gap forming rotary tool 1 is made of, for example, tool steel. The gap forming rotary tool 1 is a tool for forming a tunnel-like gap inside a metal member by rotating and rotating the metal member. For example, a metal member can be used as a cooling plate by flowing a fluid such as gas or liquid through a tunnel-shaped gap formed by this tool.

  The shoulder portion 2 has a cylindrical shape and is connected to a friction stirrer (not shown). On the bottom surface 2a of the shoulder portion 2, a ridge 2b is formed. The protrusion 2b is formed in a spiral around the stirring pin 3, as shown in FIG. The cross-sectional shape of the protrusion 2b is not particularly limited, but is rectangular in this embodiment. The number of windings of the ridge 2b is not particularly limited, but in the present embodiment, it is wound about one and a half times or more. By providing the ridge 2b, the plastic fluidized metal (base material) is easily flowed around the proximal end side of the stirring pin 3 during friction stirring.

  The start position of the protrusion 2b (distance P1 from the base end of the stirring pin 3 to the start position of the protrusion 2b) and the scroll pitch of the protrusion 2b (distance P2 between the protrusions 2b) are not particularly limited. What is necessary is just to set suitably. Further, the protrusion 2b may not be provided.

  The stirring pin 3 is concentric with the shoulder portion 2 and is suspended from the bottom surface 2 a of the shoulder portion 2. Further, the stirring pin 3 is tapered in this embodiment. The length of the stirring pin 3 is not particularly limited and may be set as appropriate.

  In the present embodiment, the outer diameter X1 of the shoulder portion 2 and the outer diameter Y2 of the tip of the stirring pin 3 are set to satisfy X1 / Y2 = 1.4 to 2.2. When it does in this way, when forming a space | gap inside a metal member by friction stirring, a space | gap is hard to be crushed and it is hard to make a surface defect in a metal member. Moreover, the load given to the friction stirrer can be reduced. The reason will be described later.

  A spiral groove 3 a is formed on the outer peripheral surface of the stirring pin 3 from the distal end to the proximal end of the stirring pin 3. In this embodiment, the spiral groove 3a is formed by groove processing with a ball end mill. The cross-sectional shape of the spiral groove 3a is not particularly limited, but is a semicircle in the present embodiment. In the present embodiment, the spiral groove 3a is formed clockwise when it is traced downward from above (right screw).

  It is preferable that the angle (lead angle) α of the spiral groove 3a with respect to a reference plane with the axial direction of the stirring pin 3 as a normal line is appropriately set between 20 and 40 degrees. When the angle α of the spiral groove 3a is less than 20 degrees, the angle is too shallow, and the plastic fluidized metal from the shoulder portion 2 is hardly scraped. On the other hand, when the angle α 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 plastic fluidized metal is hardly scraped out from the shoulder portion 2. Therefore, in any case, the voids tend to be crushed.

The number of turns of the spiral groove 3a in the axial direction is not particularly limited, but it is preferable that the spiral groove 3a is wound at least once. If it is wound more than once, the gap can be formed larger. If the number of turns of the spiral groove 3a is less than one turn, the position of the spiral groove 3a with respect to the agitation pin 3 is biased, so that the plastic fluidized metal may remain on either side wall of the formed gap. There is.
In the present embodiment, the spiral groove 3a is configured as described above. However, the spiral groove 3a may be formed counterclockwise when traced from above to below (left-hand thread).

  Next, the void forming method according to this embodiment will be described. As shown in FIG. 2, in this embodiment, the case where the flat metal member Z is processed is illustrated. The material of the metal member Z is not particularly limited, but may be selected from metals capable of friction stir, such as aluminum, aluminum alloy, copper, copper alloy, titanium, titanium alloy, magnesium, magnesium alloy.

  The gap forming rotary tool 1 is rotated above the metal member Z, the agitation pin 3 is pushed into the surface Za of the metal member Z, and the gap relative to the metal member Z is maintained at a constant height. The forming rotary tool 1 is moved. The rotational speed of the gap forming rotary tool 1 is not particularly limited, but is set, for example, between 700 and 1300 rpm. Further, the moving speed of the gap forming rotary tool 1 is set, for example, between 200 mm / min and 400 mm / min. The bottom surface 2a of the shoulder portion 2 and the surface Za of the metal member Z may be moved while being in contact with each other, or may be moved with a gap. What is necessary is just to set suitably the clearance gap (distance) K between the bottom face 2a of the shoulder part 2 and the surface Za of the metal member Z between 0-3.0 mm, for example.

  As shown in FIG. 2A, in this embodiment, since the spiral groove 3a is formed clockwise as it goes from the top to the bottom, in the gap formation method, the gap is formed clockwise as viewed from above. The rotary tool 1 is rotated. That is, the gap forming rotary tool 1 is rotated and moved in a direction in which the metal plastically fluidized by the spiral groove 3a is scraped up onto the surface Za of the metal member Z.

  Incidentally, when the spiral groove 3a is formed in the counterclockwise direction from the top to the bottom, the gap forming rotary tool 1 is formed in the direction in which the plastic fluidized metal is wound up on the surface Za of the metal member Z, that is, counterclockwise. Rotate.

  In the gap forming method, the metal member Z is frictionally stirred by the gap forming rotary tool 1, and an upward plastic flow is generated by the spiral groove 3a. Thereby, the molten metal is guided to the spiral groove 3a and scraped out to the surface Za side of the metal member Z. The scraped metal is pressed by the pressing force of the gap forming rotary tool 1 while being in contact with the bottom surface 2a. A tunnel-like gap M formed by scraping out the metal is formed on the trace where the gap-forming rotary tool 1 has passed, and a plasticized region Z2 is formed on the gap M.

  Here, as shown in FIG. 2 (b), the metal member Z after the friction stir consists of a main body part Z1, a gap M formed inside the main body part Z1, and a plasticized region covering the upper part of the gap M. Z2. The plasticized region Z2 is a portion formed by hardening after the metal is plastic fluidized by friction stirring. In the present embodiment, the plasticized region Z2 has an inverted frustum shape in cross section and is formed so as to cover the space M. The plasticized region Z2 is formed by pressing the metal frictionally stirred by the stirring pin 3 by the bottom surface 2a of the shoulder portion 2. Of the metal subjected to friction stirring, the metal overflowing from the bottom surface 2a of the shoulder portion 2 becomes a 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 gap M is formed in a substantially rectangular shape in sectional view. In the present embodiment, the gap M is a sealed space, and no surface defects communicating with the gap M are formed in the plasticized region Z2 or in the boundary portion between the main body Z1 and the plasticized region Z2. The distance from the upper end of the gap M to the surface Za is defined as “gap depth D”.

Depending on the shape of the gap-forming rotary tool 1, the gap M may be crushed without the metal being scraped suitably. On the other hand, the metal is scraped too much, and the plasticized region Z2 becomes thin, and surface defects communicating with the gap M are formed in the plasticized region Z2 or in the boundary portion between the main body Z1 and the plasticized region Z2. there is a possibility.
However, according to the gap forming rotary tool 1, the metal is suitably scraped and the scraped metal can be pressed by the bottom surface 2 a of the shoulder portion 2, so that the gap M is not easily crushed and the metal member Z Difficult to make surface defects. Moreover, the load given to the friction stirrer can be reduced. The conditions such as the ratio between the outer diameter X1 of the shoulder portion 2 and the outer diameter Y2 of the tip of the stirring pin 2 and the numerical value of the angle α of the spiral groove will be described in Examples.

  Moreover, since the stirring pin 3 according to the present embodiment has a tapered shape, the press-fit resistance when being pushed into the metal member Z can be reduced.

<First modification>
Next, a first modification of the present invention will be described. The gap forming rotary tool 1A according to the first modified example is different from the above-described embodiment in that the stirring pin 3 includes the flat surface portion 11 and the spiral groove portion 12.

  As shown in FIG. 3A, the outer peripheral surface of the stirring pin 3 according to the first modification has a flat surface portion 11 in which no groove is formed and a spiral groove portion 12 in which the spiral groove 3 a is formed. . The outer peripheral surface of the flat surface portion 11 is flat and is formed from the base end of the stirring pin 3 to almost the center of the stirring pin 3.

  On the other hand, a spiral groove 3a is formed on the outer peripheral surface of the spiral groove portion 12 from the tip to almost the center (up to the flat surface portion 11). The spiral groove 3a is preferably wound at least once. The height H1 of the spiral groove portion 12 may be appropriately set according to the depth of the gap M to be formed with respect to the metal member Z. For example, the height H1 is 30 to 70% with respect to the length of the stirring pin 3. (The height of the flat surface portion 11 is preferably 70% to 30% with respect to the length of the stirring pin 3).

In the gap forming rotary tool 1 shown in FIG. 1, since the spiral groove 3a is formed from the tip end to the base end of the stirring pin 3, the metal is relatively easily scraped, and the gap depth D is relatively small (shallow). ).
However, according to the rotation tool 1 </ b> A for gap formation according to the first modification, the metal is scraped by the spiral groove portion 12 to form the gap M, but the metal that is frictionally stirred by the flat surface portion 11 is from the shoulder portion 2. Hard to be scraped to the outside. Accordingly, since the thickness of the plasticized region Z2 is increased, the gap depth D can be increased (deeply). As a result, a large gap M can be formed in a deep position of the metal member Z, and surface defects are less likely to be formed in the plasticized region Z2 or in the boundary portion between the main body Z1 and the plasticized region Z2.

<Second modification>
Next, a second modification of the present invention will be described. As shown in FIG. 3B, the gap forming rotary tool 1B according to the second modification is described above in that the protrusions 2b formed on the bottom surface 2a of the shoulder portion 2 are formed intermittently. It is different from the embodiment.

  The ridge 2b according to the second modification includes a plurality of notches 2c that divide the ridge 2. By providing the notch portion 2c, the plastic fluidized metal passes through the notch portion 2c, so that the plastic fluidized metal flows easily in the radial direction of the bottom surface 2a of the shoulder portion 2. As a result, the metal tends to gather around the base end of the stirring pin 3, and the plastic fluidized metal is easily scraped out from the notch 2c. Thereby, a relatively large gap M can be formed. Note that the number and size of the notches 2c may be set as appropriate.

<Third modification>
Next, a third modification of the present invention will be described. As shown in FIG. 4, the gap forming rotary tool 1 </ b> C according to the third modification differs from the above-described embodiment in that the outer diameter of the stirring pin 3 is constant.

  The outer diameter Y1 of the base end of the stirring pin 3 of the rotary tool 1C for gap formation is equal to the outer diameter Y2 of the tip. Thus, the outer diameter of the stirring pin 3 may be constant. Thereby, the space | gap M formed with the space | gap formation method can be formed with a fixed width | variety.

  Although the embodiments and modifications of the present invention have been described above, design changes can be made as appropriate without departing from the spirit of the present invention.

<Summary>
Next, examples of the present invention will be described. In the examples, the void forming method was performed by changing the shape, size, ratio, etc. of each element constituting the void forming rotary tool, and the formed voids were observed. For convenience of explanation, the gap forming rotary tool is hereinafter simply referred to as “tool”.

  In the examples, five types of tests were roughly divided. "Spiral groove angle test" to investigate the effect of the tool's spiral groove angle (lead angle), "Shoulder outer diameter test" to investigate the effect of the shoulder outer diameter, The “projection test” to be investigated, the “stirring pin outer diameter test” to investigate the influence of the outer diameter of the stirring pin, and the “void depth test” to investigate the void depth of the plasticized region formed were conducted.

  In the void depth test, an A1050 alloy plate was used, and in other tests, an A1100 alloy plate was used. The cross-sectional shape of the spiral groove formed in the stirring pin has a semicircular shape, and its radius is 1.5 mm. The starting position of the ridge (distance P1 in FIG. 1B) was 3.0 mm, and the scroll pitch (distance P2 in FIG. 1B) was 2.5 mm.

  In the gap forming method, a rotated tool was inserted into the alloy plate and moved a predetermined distance. The rotation speed of the tool was basically 800 RPM, and in the air gap depth test, the influence of the rotation speed of the tool was investigated by performing frictional stirring even at 1275 RPM.

  The moving speed of the tool was 100 mm / min or 300 mm / min. Moreover, in the spiral groove angle test, the moving speed was changed between 50 to 300 mm / min, and the influence on the moving speed was also investigated.

  Furthermore, in each test, the gap from the surface of the metal member to the bottom surface of the shoulder portion (distance K in FIG. 2A) was changed to 0 mm, 1.0 mm, 2.0 mm, and 3.0 mm to obtain a single The gaps formed by friction stirring on the metal members were compared. In any alloy plate (test body), the central portion of the alloy plate was cut, polished and etched, and then the shape of the formed void was observed. Moreover, the cross-sectional area of the space | gap formed using the imaging device was measured.

<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 investigated. As shown in FIG. 5, three types of tools Nos. S1 to S3 were used in this test. The angle of the spiral groove 3a with the horizontal plane was set to 40 degrees for tool No. S1, 30 degrees for tool NO. S2, and 20 degrees for tool NO. S3. Further, the number of turns of the spiral groove of each tool in the axial direction of the stirring pin 3 is about 0.8 lap for the tool NO.S1, about 1.3 lap for the tool NO.S2, and about 2.3 for the tool NO.S3. It is around.

  The configuration other than the angle of the spiral groove 3a is the same for all three types. The outer diameter of the shoulder portion 2 is 22 mm, 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, The length was set to 11 mm. Each tool includes a spiral protrusion 2 b on the bottom surface 2 a of the shoulder portion 2. The height of the protrusion 2b was 1 mm.

6 is a plan view of the metal member showing the test result of the spiral groove angle test, where (a) shows the result of tool NO.S1, (b) shows the result of tool NO.S2, and (c) shows the tool NO. The result of S3 is shown. In FIGS. 6A, 6B, and 6C, four plasticized regions Z2 are formed on the surface Za of the metal member Z (main body portion Z1). The plasticized region Z2 is, in order from the top of the drawing, when the gap from the surface Za of the metal member Z to the bottom surface 2a of the shoulder portion 2 is 0 mm, 1.0 mm, 2.0 mm, 3.0 mm Shows the results of the case.
7A is a cross-sectional view taken along the line II-II of FIG. 6A, FIG. 7B is a cross-sectional view taken along the line II-II of FIG. 6B, and FIG. 7C is a cross-sectional view taken along the line II of FIG. It is -II sectional drawing.

  As shown in FIGS. 6A to 6C, under the conditions of a gap of 0 mm and 1.0 mm, the entire bottom surface 2a of the shoulder portion 2 comes into contact with the plastic fluidized metal and a large burr V is generated. ing. When the gap was 2.0 mm, the entire bottom surface 2a of the shoulder portion 2 was in contact with the plastic fluidized metal, but the burr V was relatively small. When the gap was 3.0 mm, the width of the plasticized region Z2 formed by plastic fluidization was shorter than the outer diameter X1 of the shoulder portion 2 (see FIG. 1A).

  Here, as shown in FIGS. 6 and 7, the side on which the moving speed of the tool is added to the rotational speed of the tool is referred to as “Advancing side” (hereinafter also referred to as “Ad side”), and the rotational speed of the tool is The side on which the moving speed is subtracted is referred to as “Retreating side” (hereinafter also referred to as “Re side”). In the present embodiment, while the tool is rotated clockwise, the tool is moved from the left to the right in FIG. 6, so the left side in the traveling direction is the Ad side and the right side is the Re side.

As shown to (a) of FIG. 7, the space | gap M in tool NO.S1 exhibits a vertically elongate rectangular shape. The plasticized region Z2 covers the gap M, but a part of the plasticized area Z2 remains on the Re side wall of the gap M.
On the other hand, in the tool NO. S2 and the tool NO. S3, the gap M having substantially the same shape is formed under the condition of the gap 1.0 to 3.0, and the plastic fluidized metal is formed on the side wall of the gap M. It is discharged outside without remaining.

  In tools NO. S1 to S3, it was found that the height position of the gap M was moved above the metal member Z and the height of the gap M was increased as the gap was increased. Moreover, it turns out that the cross-sectional area of the plasticization area | region Z2 becomes small and the space | gap depth D from the upper end of the space | gap M to the surface Za of the metal member Z becomes small as a clearance gap becomes large with tool NO.S1-S3. It was.

  Further, in the tool NO. S2 and the tool NO. S3, the width of the formed gap M and the outer diameter of the tip of the stirring pin 2 were substantially equal, but in the tool NO. S1, the width of the formed gap was It was smaller than the outer diameter of the tip of the stirring pin 2. As shown in FIG. 7A, a part of the plasticized region Z2 remains on the side wall of the gap M on the Re side. This is considered to be caused by the angle and the number of windings of the spiral groove 3a of the NO.S1 tool.

  Tool No. S1 has a short spiral groove 3a with respect to the stirring pin 3 because the angle of the spiral groove 3a is as deep as 40 degrees. Therefore, it is considered that the plastic fluidized metal is difficult to be discharged. Moreover, in tool No. 1, since the number of turns of the spiral groove 3a is less than one turn, the position of the spiral groove 3a with respect to the stirring pin 3 is biased. For this reason, it is considered that the plasticized metal remains on one side wall (here, Re side) of the formed gap M.

  FIG. 8 is a graph showing the relationship between the gap area and the gap in the spiral groove angle test for each tool. As shown in FIGS. 7 and 8, the gap area of the gap M formed by the tool NO. S2 and the tool NO. S3 is substantially the same, but the gap area obtained by the tool NO. S1 is It was smaller than the void area of S2 and tool NO.S3.

Further, as shown in FIG. 8, the gap area (cross-sectional area of the gap M) increased as the gap increased with the tools No. S1 to S3. In short, it has been found that if the tool is separated from the metal member Z to facilitate scraping out the plastic fluidized metal, the void area of the void M can be increased. Increasing the proportion of both tools NO.S1~S3 void area (slope of the graph) has become substantially equal to the outer diameter of the tip of about ^{7 mm} 2 / A mm stirring pin 3.

FIG. 9 is a graph showing the relationship between the gap area and the gap in the spiral groove angle test for each moving speed. Since the tool NOs. S1 to S3 have substantially 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 gap area and the moving speed in the spiral groove angle test for each gap. FIG. 10 shows the relationship between the gap area obtained with the tool No. S3 and the moving speed.
As apparent from FIGS. 9 and 10, it was found that the gap area is not significantly affected by the change in the moving speed.

<Shoulder outer diameter test>
In the shoulder part outer diameter test, the influence of the outer diameter of the shoulder part 2 was investigated. As shown in FIG. 11, three types of tools NO. T1 to T3 were used in this test. The outer diameter of the shoulder portion 2 was set to 20 mm for tool NO. T1, 18 mm for tool NO. T2, and 16 mm for tool NO. T3. The configuration other than the outer diameter of the shoulder portion 2 is the same for all three types. The outer diameter of the base end of the stirring pin 3 is set to 10 mm, the outer diameter of the distal end is set to 7 mm, and the length of the stirring pin 3 is set to 11 mm. Each tool includes a spiral protrusion 2 b on the bottom surface 2 a of the shoulder portion 2. The height of the protrusion 2b was 1 mm.

  12 is a plan view of the metal member showing the test result of the shoulder portion outer diameter test, where (a) shows the result of tool NO.T1, (b) shows the result of tool NO.T2, and (c) shows the tool. The result of NO.T3 is shown. 13A is a sectional view taken along line III-III in FIG. 12A, FIG. 13B is a sectional view taken along line III-III in FIG. 12B, and FIG. 13C is a sectional view taken from FIG. It is III-III sectional drawing. As shown in FIG. 5 (c), the tool NO. S3 described above has an outer diameter of the shoulder portion 2 of 22 mm, and other configurations are the same as the tools NO. T1 to T3. (C) of FIG. 7 and (c) of FIG.

  By reducing the outer diameter of the shoulder portion 2, even if the gap is 2.0 mm, the plastic fluidized metal comes into contact with the bottom surface 2a of the shoulder portion 2 and a large amount of burr V is discharged from the Re side. I understood. When the gap is 3.0 mm, the burrs V are discharged on the Re side, but the surface defect E communicating with the gap M is formed by the lack of metal in the plasticized region Z2 in the tool NO.T1 and the tool NO.T3. .

  On the other hand, the height of the space | gap M increased as the outer diameter of the shoulder part 2 became small. By reducing the outer diameter of the shoulder portion 2, the metal pressed by the bottom surface 2a of the shoulder portion 2 is reduced. For this reason, it is considered that the plastic fluidized metal is easily scraped off, which leads to an increase in the height of the gap M.

  14 and 15 are graphs showing the relationship between the gap area and the gap in the shoulder portion outer diameter test for each tool. FIG. 14 shows the moving speed of 100 mm / min, and FIG. 15 shows the moving speed of 300 mm / min. The result when set to.

As shown in FIGS. 14 and 15, the gap area increased as the gap increased in all tools. In short, it has been found that if the tool is separated from the metal member Z to facilitate scraping out the plastic fluidized metal, the void area of the void M can be increased. The increase ratio (inclination of increase) in the gap area was about 7 mm ² / mm for both tool NO.S3 and tool NO.T1 to T3, which was the same as the outer diameter of the tip of the stirring pin 3.

  FIGS. 16 and 17 are graphs showing the relationship between the gap area and the outer diameter of the shoulder portion in the shoulder portion outer diameter test for each gap. FIG. 16 shows the moving speed at 100 mm / min, and FIG. 17 shows the moving speed. The result is shown when is set to 300 mm / min.

As shown in FIGS. 16 and 17, under the condition of a gap of 2.0 mm, the gap area obtained when the outer diameter of the shoulder portion 2 is 22 mm and the gap area obtained when the outer diameter of the shoulder portion 2 is 20 mm are as follows. It was almost equivalent. In the range where the outer diameter of the shoulder portion 2 is 20 mm to 16 mm, the void area increased as the outer diameter of the shoulder portion 2 decreased. The increase rate of the void area (inclination of 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 gap 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 void area becomes smaller. Increased linearly. This is considered to be because the pressurization from the shoulder portion 2 decreases as the outer diameter of the shoulder portion 2 decreases, and the discharged metal increases.
On the other hand, as shown in FIG. 17, when the moving speed is 300 mm / min and the gap is 3.0 mm, the outer diameter of the shoulder portion 2 is 16 mm and 18 mm, and surface defects are generated in the plasticized region. Diminished.

<Projection test>
In the ridge test, the influence of the ridge 2b formed on the bottom surface 2a of the shoulder portion 2 was investigated. As shown in FIG. 18, three types of gap forming rotary tool tools No. S3-1 to S3-3 were used in this test. The width of the notch 2c of the ridge 2b was set to 2 mm for the tool No. S3-1 and 6 mm for the tool No. S3-2. Tool No. S3-3 has no protrusions. The configuration other than the protrusion 2b is the same for all three types. The outer diameter of the shoulder portion 2 is 22 mm, 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 is It was set to 11 mm.

  19 is a cross-sectional view of the metal member showing the test result of the ridge test, where (a) shows the result of tool NO. S3-1, (b) shows the result of tool NO. S3-2, and (c). Indicates the result of tool No. S3-3. FIG. 20 is a graph showing the relationship between the gap area and the gap in the ridge test for each tool. As shown in FIG. 5 (c), the gap forming rotary tool tool NO.S3 includes the protrusion 2b without the notch 2c, and the other configuration is the tool NO.S3-1. Since it is equivalent to S3-3, it will be considered in comparison with (c) of FIG. 6 and (c) of FIG.

  As shown in (c) of FIG. 7, (a) of FIG. 19, and FIG. 20, the gap 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 and the result of tool NO. 3-3 were compared, it was found that the presence or absence of the protrusion 2b had no effect on the result of the gap area. However, comparing (c) of FIG. 7 and (c) of FIG. 19, it has been found that the shape of the gap M of the tool No. 3 having the protrusions 2b is better. This is considered to be due to the fact that the plastic fluidized metal tends to gather around the base end side of the stirring pin 3 due to the protrusion 2b.

  Like tool No. 3-2, when the length of the notch 2c was 6 mm and the length was relatively large, the gap area was also large. This is considered to be because when the length of the notch portion 2c is large, the plastic fluidized metal easily flows in the radial direction of the bottom surface 2a of the shoulder portion 2, and this metal is easily scraped.

<Stirring pin outer diameter test>
In the stirring pin outer diameter test, the influence of the outer diameter of the stirring pin 3 was investigated by varying the size of the outer diameter while keeping the outer diameter of the stirring pin 3 constant. As shown in FIG. 21, in this test, four types of gap forming rotary tool tools No. U1 to U4 were used. The outer diameter of the stirring pin 3 was set to 10 mm for the tool No. U1, 12 mm for the tool No. U2, 14 mm for the tool No. U3, and 16 mm for the tool No. U4. The configuration other than the outer diameter of the stirring pin 3 is the same for all four types, the outer diameter of the shoulder portion 2 is set to 22 mm, and the length of the stirring pin 3 is set to 11 mm. Each tool includes a spiral protrusion 2 b on the bottom surface 2 a of the shoulder portion 2. The height of the protrusion 2b was 1 mm.

  As shown in FIG. 22 (d), it was found that a surface defect E was generated under the condition of a clearance of 3.0 mm in the tool No. U4. As shown in FIG. 22 and FIG. 23, it was found that the gap area was increased as the gap was increased in the tool Nos. U1 to U4. The increase ratio (slope of the graph) of the void area of the tools No. U1 to U3 was a value close to the outer diameter of the stirring pin 3 of each tool.

In other words, increasing rate (slope of the graph) of the void area of the tool NO.U1 increase the percentage of void area of 10 mm ² / mm, in FIG. 24 10.7 mm ² / mm, tool NO.U2 in Figure 23 In Figure 23 12.6 mm ² / mm, Figure 24 in 12.5 mm ² / mm, increasing the proportion of the void area of the tool NO.U3 was 23 at 13.7 mm ² / mm, in FIG. 24 14.4 mm ² / mm . It is considered that when the gap is increased by 1 mm in each tool, the gap M is increased by the outer diameter of the stirring pin 3, so that the formed gap area is also increased by the outer diameter of the stirring pin 3.

  Note that, as shown in FIGS. 23 and 24, it was found that the difference in moving speed does not affect the gap area. Further, as shown in FIG. 25, it was found that the void area increases as the outer diameter of the stirring pin 3 increases, but the increasing tendency is a quadratic function.

<Cavity depth test>
In the gap depth test, as shown in FIG. 3A, the depth position of the gap M to be formed is determined by using a gap forming rotary tool having a flat surface portion 11 in which the spiral groove 3a is not formed. investigated. As shown in FIG. 26, three types of gap forming rotary tools were used in this test. Tool NO. T2 is a comparative example and is equivalent to the tool shown in FIG.

  As shown in FIG. 27A, the height of the spiral groove 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 NO. T2-1 is 3.5 mm, and the height of the spiral groove portion 12 is 7.5 mm. As shown in FIG. 28A, the height of the flat surface portion 11 of the tool NO. T2-2 is 6.0 mm, and the height of the spiral groove portion 12 is 5.0 mm.

  The configuration other than the height of the spiral groove portion 12 is the same for all three types. The outer diameter of the shoulder portion 2 is 18 mm, the outer diameter of the proximal end of the stirring pin 3 is 10 mm, and the outer diameter of the distal end is 7 mm. All of the tools are provided with a spiral protrusion 2b on the bottom surface 2a of the shoulder portion 2. The height of the protrusion 2b was 1 mm. In the gap depth test, the gaps from the surface Za of the metal member Z to the bottom surface 2a of the shoulder portion 2 were set to three types: 0 mm, 1.0 mm, and 2.0 mm. In addition, each tool was tested at two types of rotation speeds of 800 RPM and 1275 RPM.

  27 is a cross-sectional view showing the test results of the void depth test, where (a) and (b) are the results of tool NO. T2, and (c) and (d) are the results of tool NO. T2-1. Indicates. 28 is a cross-sectional view showing the test results of the void depth test, and (a) and (b) show the results of tool NO.T2-2. FIG. 29 is a graph showing the relationship between the gap depth and the height of the flat surface portion in the gap depth test for each gap. FIG. 30 is a graph showing the relationship between the gap depth and the height of the flat surface portion in the gap depth test for each gap. 29 and 30 are different in the rotation speed of the tool, the rotation speed of the test according to FIG. 29 is 800 RPM, and the rotation speed of the test according to FIG. 30 is 1275 RPM.

  As shown in FIGS. 29 and 30, it was found that the gap depth D increases as the height of the flat surface portion 11 (length of the stirring pin 3−height of the spiral groove portion 12) increases. Moreover, it turned out that the space | gap depth D becomes large, so that a clearance gap becomes small. When FIG. 29 and FIG. 30 are compared, it is found that the gap depth D is slightly increased when the rotational speed of the tool is higher.

  FIG. 31 is a graph showing the relationship between the gap area and the gap in the gap depth test according to the height of the spiral groove. FIG. 32 is a graph showing the relationship between the gap area and the gap in the gap depth test according to the height of the spiral groove. FIG. 31 and FIG. 32 are different in the rotation speed of the tool, the rotation speed of the test according to FIG. 31 is 800 RPM, and the rotation speed of the test according to FIG. 32 is 1275 RPM.

As shown in FIGS. 31 and 32 and FIGS. 27 and 28, it has been found that the gap area increases as the height of the spiral groove portion 11 increases. Comparing FIG. 31 with FIG. 32, it was found that the number of rotations of the tool had almost no effect on the increase or decrease of the gap area.
From the above, according to the gap test, it was found that the gap M can be formed at a deep position when the height of the flat surface portion 11 is increased. On the other hand, it was found that when the height of the flat surface portion 11 is excessively increased, the void area of the void M is decreased.

<Outer diameter of shoulder portion / outer diameter of tip of stirring pin and comparison of test results>
FIG. 33 and FIG. 34 are tables showing the status of each tool and the formed gap in the example. “◯” in the “situation” item indicates that the state of the void M is good, and “x” indicates a state in which the surface defect E is generated.

  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 stirring pin is 1.4 to 2.2, the surface defect E does not occur, and the gap M The condition was generally good. If the value is less than 1.4, the scraped metal cannot be pressed by the bottom surface 2a of the shoulder portion 2, and thus surface defects E are easily generated. On the other hand, when this value is larger than 2.2, the plastic fluidized metal is hardly scraped out from the shoulder portion 2, so that the gap is easily crushed. Further, if this value is larger than 2.2, the load applied to the main shaft motor of the friction stirrer increases, which is not preferable.

DESCRIPTION OF SYMBOLS 1 Rotation tool for space | gap formation 2 Shoulder part 2a Bottom face 2b Projection 2c Notch part 3 Stirring pin 3a Spiral groove D Cavity depth K Crevice M Cavity V Burr Z Metal member Z1 Main part Z2 Plasticization area Za Surface

Claims (4)

A void forming method for forming a void presenting a substantially rectangular cross-sectional view inside an aluminum alloy member using a void forming rotary tool,
The gap forming rotary tool is:
It has a shoulder part and a stirring pin hanging from this shoulder part,
A spiral groove is engraved on the outer peripheral surface of the stirring pin, and the spiral groove is formed clockwise so as to go downward from above.
A 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 1.4 or more and 3.1 or less, and with respect to a reference plane whose normal is the axial direction of the stirring pin The angle of the spiral groove is set to 20 degrees or more and 40 degrees or less, 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.
A gap forming method, wherein when the gap forming rotary tool is moved relative to the aluminum alloy member, the gap forming rotary tool is rotated clockwise as viewed from above. A void forming method for forming a void presenting a substantially rectangular cross-sectional view inside an aluminum alloy member using a void forming rotary tool,
The gap forming rotary tool is:
It has a shoulder part and a stirring pin hanging from this shoulder part,
A spiral groove is engraved on the outer peripheral surface of the stirring pin, and the spiral groove is formed to be counterclockwise as it goes downward from above,
A 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 1.4 or more and 3.1 or less, and with respect to a reference plane whose normal is the axial direction of the stirring pin The angle of the spiral groove is set to 20 degrees or more and 40 degrees or less, 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.
A gap forming method, wherein the gap forming rotary tool is rotated counterclockwise as viewed from above when the gap forming rotary tool is moved relative to the aluminum alloy member.   The gap forming method according to claim 1 or 2, wherein the spiral groove is wound around the outer peripheral surface of the stirring pin one or more times.   The void forming method according to any one of claims 1 to 3, wherein the stirring pin is formed with a constant outer diameter from a distal end to a proximal end.

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