JP2019188412A - Friction stir welding method - Google Patents

Abstract

To provide a friction stir welding method having a high degree of freedom of design.SOLUTION: In the friction stir welding method, friction stirring is performed to a butted part J1 of a metal member 1 to be welded formed by butting end faces of a columnar first metal member 1a and a cylindrical second metal member 1b to each other, using a rotary tool F for main welding comprising a stirring pin F2. The rotary tool F for main welding comprises a flat face F4 perpendicular to a rotation shaft C and a protrusion part F5 that protrudes from the flat face F4. In the method, the rotary tool F for main welding is made to go around a circumference of the metal member 1 to be welded in a state where a tip of the protrusion part F5 is inserted deeper than a position of an outer peripheral surface 13a of a small diameter part 3 of the first metal member 1a while inserting only the stirring pin F2 into the butted part J1 and contacting the flat face F4 with the first metal member 1a and the second metal member 1b.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a friction stir welding method for joining metal members together by friction stirring.

  Friction stir welding (FSW = Friction Stir Welding) is known as a method for joining metal members. Friction stir welding is a process in which the rotating tool is rotated and moved along the abutting portion between the metal members, and the metal at the abutting portion is plastically flowed by the frictional heat between the rotating tool and the metal member, thereby fixing the metal members to each other. Phase joining is performed.

  For example, when joining a pair of cylindrical metal members, friction stir welding may be performed in the circumferential direction along the abutting portion in a state where the end surfaces of both metal members are abutted (see Patent Document 1). FIG. 15 is a cross-sectional view showing a state before joining in the conventional friction stir welding method, and FIG. 16 is a cross-sectional view showing during joining in the conventional friction stir welding method.

  As a conventional friction stir welding method, as shown in FIGS. 15 and 16, after the end portions of the columnar first metal member 100 and the cylindrical second metal member 110 are butted together, along the butted portion J1. In some cases, the rotary tool 120 is relatively moved to perform friction stir welding.

The first metal member 100 includes a cylindrical large-diameter portion 101 and a cylindrical small-diameter portion 102 formed at the end of the large-diameter portion 101. The outer diameter of the second metal member 110 is substantially the same as the outer diameter of the large diameter portion 101.
The end surface 101a of the large-diameter portion 101 of the first metal member 100 and the end surface 110a of the second metal member 110 are abutted to form a butted portion J1. The thicknesses of the end surface 101a of the large-diameter portion 101 of the first metal member 100 and the end surface 110a of the second metal member 110 are substantially equal.

As shown in FIG. 16, the rotary tool 120 includes a cylindrical shoulder portion 121 and a stirring pin 122 protruding from the lower end surface of the shoulder portion 121.
In the conventional friction stir welding method, the rotated rotating tool 120 is made to make one turn along the abutting portion J1 while the lower end surface of the shoulder portion 121 is pushed into the first metal member 100 and the second metal member 110 by about several millimeters. .

JP 2003-112272 A

  However, in the above-described conventional friction stir welding method, as shown in FIG. 16, a large pressing force is applied to the first metal member 100 and the second metal member 110 by the shoulder portion 121. There is a problem of leaking inside. In order to prevent the metal material from flowing out, there is a problem that the thickness (height) of the small-diameter portion 102 must be set large, and the degree of design freedom is limited.

  Then, this invention makes it a subject to solve the above-mentioned problem and to provide the friction stir welding method with a high freedom degree of design.

  In order to solve the above problems, the present invention provides a columnar first metal member having a small diameter portion at an end of a large diameter portion, and a cylindrical second metal member having an outer diameter substantially equal to the large diameter portion. And a friction stir welding method for performing friction stir using a rotary tool equipped with a stirring pin against a butted portion of the metal member to be joined formed by abutting the end surfaces with each other, wherein the rotating tool includes the stirrer A flat surface that is formed at the tip of the pin and is perpendicular to the rotation axis of the rotary tool, and a protrusion that protrudes from the flat surface, and only the stirring pin is inserted into the butting portion, and the flat surface is The rotating tool is placed in the state where the tip of the protrusion is inserted deeper than the position of the outer peripheral surface of the small diameter portion of the first metal member while being in contact with the first metal member and the second metal member. It is characterized by making a round around the joint metal member

  According to such a friction stir welding method, the shoulder portion is not allowed to enter the first metal member and the second metal member as in the prior art, so that the width of the plasticized region can be made smaller than in the past, and the first The pressing force acting on the metal member and the second metal member can be reduced. Thereby, even if the thickness (height) of the small-diameter portion is reduced, it is possible to prevent the metal material from flowing out into the bonded metal member, so that the degree of design freedom can be improved.

  Moreover, according to this friction stir welding method, since only the stirring pin is inserted into the first metal member and the second metal member, the load applied to the friction stirrer can be reduced as compared with the case where the shoulder portion of the rotary tool is pushed. Can do. In addition, since the load applied to the friction stirrer can be reduced, the deep position of the butt portion can be joined in a state where a large load is not applied to the friction stirrer.

  Moreover, according to this friction stir welding method, the plastic fluidized material that has been frictionally stirred along the protrusions of the stirring pin and wound up on the protrusions is pressed down on a flat surface. Thereby, the periphery of the protrusion can be reliably frictionally stirred, and the oxide film between the outer peripheral surface of the small diameter portion of the first metal member and the inner peripheral surface of the second metal member can be reliably divided. Therefore, the joining strength of the butt portion can be increased.

  Moreover, it is preferable that the start end and the termination | terminus of the plasticization area | region formed in the said butt | matching part overlap, and a part of said plasticization area | region overlaps.

  According to such a friction stir welding method, a part of the plasticized region overlaps, so that the water tightness and air tightness of the joint can be improved.

  In addition, it is preferable that the rotary tool is rotated around the metal member to be joined in a state where the rotation center axis of the rotary tool is positioned on the first metal member side with respect to the abutting portion.

  In the plasticized region formed by friction stir welding, there is a possibility that a bonding defect may be formed. When the bonding defect is formed on the second bonding metal member side which is a hollow member, the water tightness of the metal member to be bonded In addition, airtightness may be reduced. However, according to such a friction stir welding method, even if a bonding defect is formed, it is formed at a position away from the second metal member, so that it is possible to suppress a decrease in water tightness and air tightness of the metal member to be joined. Can do.

  Further, when the first metal member is located on the left side in the advancing direction of the rotary tool, the rotary tool is rotated to the right, and when the first metal member is located on the right side in the advancing direction of the rotary tool, the rotary tool is It is preferable to rotate counterclockwise.

  In friction stir welding, there is a possibility that a joint defect may occur on the left side in the traveling direction when the rotary tool is rotated to the right, and on the right side in the traveling direction when the rotary tool is rotated to the left. If formed, the water tightness and air tightness of the metal member to be joined may be lowered. However, according to such a manufacturing method, even if a bonding defect is formed, since it is formed at a position away from the second metal member, it is possible to suppress a decrease in watertightness and airtightness of the bonded metal member. .

  Further, it is preferable that the rotary tool is moved toward the first metal member from the end of the plasticized region formed in the butting portion, and the drawing position of the rotary tool is provided in the first metal member.

  According to this friction stir welding method, it is possible to prevent the metal material from flowing into the bonded metal member. Moreover, since the extraction | drawer trace of a rotary tool is formed in the position away from the 2nd metal member, the fall of the watertightness of a to-be-joined metal member and airtightness can be suppressed.

  In addition, prior to the step of friction stir welding with the rotary tool, it is preferable that a part of the butting portion is temporarily joined using a temporary joining rotary tool smaller than the rotary tool.

  According to this friction stir welding method, it is possible to prevent the opening of the first metal member and the second metal member when friction stir is performed with the rotary tool.

  The present invention also provides a first metal member having a columnar small diameter portion at an end of a columnar large diameter portion, and a cylindrical second metal member having an outer diameter substantially equal to the large diameter portion. Is a friction stir welding method for performing friction stir using a rotary tool provided with a stirring pin against a butted portion of the metal member to be joined formed by abutting the end surfaces with each other. A flat surface perpendicular to the rotation axis of the rotary tool, and a protrusion protruding from the flat surface, only the stirring pin is inserted into the butting portion, and the flat surface is The rotating tool is connected to the workpiece while the tip of the protrusion is inserted deeper than the position of the outer peripheral surface of the small diameter portion of the first metal member while being in contact with the first metal member and the second metal member. One round is made around the metal member.

  According to such a friction stir welding method, the shoulder portion is not allowed to enter the first metal member and the second metal member as in the prior art, so that the width of the plasticized region can be made smaller than in the past, and the first The pressing force acting on the metal member and the second metal member can be reduced. Thereby, even if the thickness (height) of the small-diameter portion is reduced, it is possible to prevent the metal material from flowing out into the bonded metal member, so that the degree of design freedom can be improved.

  Moreover, according to this friction stir welding method, since only the stirring pin is inserted into the first metal member and the second metal member, the load applied to the friction stirrer can be reduced as compared with the case where the shoulder portion of the rotary tool is pushed. Can do. In addition, since the load applied to the friction stirrer can be reduced, the deep position of the butt portion can be joined in a state where a large load is not applied to the friction stirrer.

  Further, according to the friction stir welding method, the plastic fluidized material that is frictionally stirred along the protruding portion of the stirring pin and wound up on the protruding portion is pressed by the flat surface of the stirring pin. Thereby, the periphery of the protrusion can be reliably frictionally stirred, and the oxide film between the outer peripheral surface of the small diameter portion of the first metal member and the inner peripheral surface of the second metal member can be reliably divided. Therefore, the joining strength of the butt portion can be increased.

  According to the friction stir welding method of the present invention, the degree of freedom in design can be improved.

It is the side view which showed the rotation tool for this joining of this embodiment. It is the schematic cross section which showed the joining form of the rotary tool for this joining of this embodiment. It is the side view which showed the rotary tool for temporary joining of this embodiment. It is the schematic cross section which showed the joining form of the rotary tool for temporary joining of this embodiment. It is the disassembled perspective view which showed the to-be-joined metal member which concerns on embodiment of this invention. It is sectional drawing which showed the butt | matching state of the to-be-joined metal member which concerns on embodiment of this invention. It is the perspective view which showed the state which joined the to-be-joined metal member which concerns on embodiment of this invention. It is the perspective view which showed the temporary joining process of the friction stir welding method which concerns on embodiment of this invention. It is the perspective view which showed the start step of the main joining process of the friction stir welding method which concerns on embodiment of this invention. It is XX sectional drawing of FIG. It is a perspective view which shows the middle stage of the main joining process of the friction stir welding method which concerns on embodiment of this invention. It is the perspective view which showed the completion | finish stage of the main joining process of the friction stir welding method which concerns on embodiment of this invention. It is sectional drawing which showed the modification of the main joining process of the friction stir welding method which concerns on embodiment of this invention. It is the top view which showed the modification of the main joining process of the friction stir welding method which concerns on embodiment of this invention. It is sectional drawing which showed before joining in the conventional friction stir welding method. It is sectional drawing which showed during joining in the conventional friction stir welding method.

A friction stir welding method according to an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.
First, the main joining rotary tool and the temporary joining rotary tool used in the present embodiment will be described.

  As shown in FIG. 1, the main rotating tool for joining F includes a connecting portion F1 and a stirring pin F2. The main joining rotary tool F corresponds to a “rotary tool” in the claims. The main rotating tool F for joining is formed of, for example, tool steel. The connection part F1 is a part connected to the rotation main shaft D of the friction stirrer shown in FIG. The connecting portion F1 has a cylindrical shape, and is formed with screw holes B and B to which bolts are fastened.

The stirring pin F2 hangs down from the connecting portion F1 and is coaxial with the connecting portion F1. Further, the agitation pin F2 includes a flat surface F4 and a protrusion F5. The stirring pin F2 is tapered as it is separated from the connecting portion F1. The length of the stirring pin F2 is larger than the plate thickness of the second metal member 1b described later.
A spiral groove F3 is formed on the outer peripheral surface of the stirring pin F2. In the present embodiment, the spiral groove F3 is formed in a counterclockwise direction from the proximal end toward the distal end in order to rotate the main joining rotary tool F to the right.

The main rotating tool for joining F includes a flat surface F4 formed at the tip of the stirring pin F2, and a protrusion F5 protruding from the flat surface F4. The flat surface F4 is a surface perpendicular to the rotation center axis C of the main welding rotary tool F.
The protruding portion F5 is a portion that protrudes downward from the central portion of the flat surface F4. The shape of the protrusion F5 is not particularly limited, but in the present embodiment, it is a columnar shape. A step portion is formed by the side surface of the protrusion F5 and the flat surface F4. In addition, you may provide a spiral groove in the outer peripheral surface of the projection part F5.

  In addition, when rotating this welding rotation tool F counterclockwise, it is preferable to form the spiral groove F3 in the clockwise direction from the proximal end toward the distal end. By setting the spiral groove F3 in this way, the plastic fluidized metal at the time of frictional stirring is guided to the tip side of the stirring pin F2 by the spiral groove F3. Thereby, the quantity of the metal which overflows to the exterior of the to-be-joined metal member 1 (1a, 1b) can be decreased.

  As shown in FIG. 2, when the friction stir welding is performed using the rotating tool F for main joining, only the rotated stirring pin F2 is inserted into the metal member 1 to be joined, and the metal member 1 to be joined and the connecting portion F1. And move it apart. In other words, the friction stir welding is performed with the base end portion of the stirring pin F2 exposed. A plasticized region W is formed in the movement locus of the main rotating tool F for bonding by hardening the friction-stirred metal.

  As shown in FIG. 3, the temporary bonding rotary tool G includes a shoulder G <b> 1 and a stirring pin G <b> 2. The temporary joining rotary tool G is made of, for example, tool steel. The temporary joining rotary tool G is smaller than the main joining rotary tool F. That is, the length dimension of the stirring pin G2 is about 1/4 of the length dimension of the stirring pin F2. As shown in FIG. 4, the shoulder G <b> 1 is a part that is connected to the rotation main shaft D of the friction stirrer and is a part that holds the plastic fluidized metal. The shoulder G1 has a cylindrical shape. The lower end surface of the shoulder G1 has a concave shape to prevent the fluidized metal from flowing out.

  The stirring pin G2 hangs down from the shoulder G1 and is coaxial with the shoulder G1. The stirring pin G2 is tapered as it is separated from the shoulder G1. A spiral groove G3 is formed on the outer peripheral surface of the stirring pin G2.

  As shown in FIG. 4, when the friction stir welding is performed using the rotary tool G for temporary joining, the rotated stirring pin G2 and the lower end surface of the shoulder G1 are inserted into the metal member 1 (1a, 1b) to be joined. While moving relative. A plasticized region W <b> 1 is formed in the movement locus of the temporary bonding rotary tool G by hardening the friction-stirred metal.

  Next, the 1st metal member 1a and the 2nd metal member 1b joined by this embodiment are demonstrated. As shown in FIG.5 and FIG.6, in this embodiment, the substantially cylindrical 1st metal member 1a and the cylindrical 2nd metal member 1b are joined by friction stirring.

As shown in FIG. 5, the first metal member 1 a is a metal member that has a substantially cylindrical shape, and includes a large diameter portion 2 and a small diameter portion 3 that has a cylindrical shape protruding from the end surface 11 a of the large diameter portion 2. And have. The large diameter portion 2 and the small diameter portion 3 are formed by concentric shafts.
The second metal member 1b is a metal member having a cylindrical shape. The first metal member 1a and the second metal member 1b have substantially the same outer diameter, and the outer diameter of the small diameter portion 3 of the first metal member 1a and the inner diameter of the second metal member 1b are formed to be substantially equal. Yes.

  In the present embodiment, the first metal member 1a and the second metal member 1b are metal materials having the same composition, for example, friction such as aluminum, aluminum alloy, copper, copper alloy, titanium, titanium alloy, magnesium, and magnesium alloy. It is made of a stirrable metal material.

  As shown in FIG. 7, the to-be-joined metal member 1 formed by abutting the first metal member 1a and the second metal member 1b makes the relative rotation tool F (see FIG. 1) relative to the outer peripheral surface. It is moved and integrated by friction stir welding. For example, a sealed container, a torque rod, or the like can be formed by the friction stir welding method according to the present embodiment.

  Next, the friction stir welding method according to this embodiment will be described. In the friction stir welding method according to the present embodiment, a butt process, a temporary bonding process, and a main bonding process are performed.

  As shown in FIG. 6, the butting step is a step of forming the metal member 1 to be joined by butting the first metal member 1 a and the second metal member 1 b at the end surfaces. That is, the end surface 11a of the first metal member 1a and the end surface 11b of the second metal member 1b are brought into close contact with each other. As described above, the outer diameter of the first metal member 1a (the outer diameter of the large-diameter portion 2) and the outer diameter of the second metal member 1b are substantially the same. The outer peripheral surfaces 12a and 12b are flush with each other. Moreover, since the outer diameter of the small diameter part 3 of the 1st metal member 1a and the internal diameter of the 2nd metal member 1b are formed substantially equal, when both members are faced, the outer peripheral surface 13a of the small diameter part 3 and the first The inner peripheral surface 13b of the bimetallic member 1b is in surface contact.

  The end face 11a of the first metal member 1a and the end face 11b of the second metal member 1b are abutted to form a butt portion J1. The butted portion J1 is continuously formed over the outer peripheral surface of the metal member 1 to be joined. The metal member 1 to be bonded is fixed so as not to move to a fixing jig that can rotate around an axis.

  As shown in FIG. 8, the temporary joining step is a step of temporarily joining the butt joint J1. In the temporary joining step, the temporary joining rotary tool G rotated clockwise is relatively moved along the abutting portion J1. In the present embodiment, the metal member 1 to be bonded is rotated around the axis while the rotary tool G for temporary bonding is driven to rotate around the rotation axis. In this embodiment, when the temporary joining rotary tool G moves relative to the metal member 1 to be joined, the first metal member 1a is set on the left side in the traveling direction. The temporary joining step may be performed continuously along the butt portion J1, or may be performed intermittently as in the present embodiment.

  As shown in FIG. 9, the main joining step is a step of performing friction stir welding on the butt joint J <b> 1 in earnest using the main welding rotary tool F. In the main joining step, first, the main welding rotating tool F rotated to the right is inserted into the start position s1 set in the first metal member 1a. Then, the main welding rotary tool F is relatively moved toward the first intermediate point s2 set in the abutting portion J1. The end portion (starting end Wa) of the plasticized region at the first intermediate point s2 is a portion that becomes the “starting end of the plasticized region formed in the butt portion” in the claims.

When the main welding rotary tool F reaches the first intermediate point s2, the metal member 1 to be bonded is rotated around the axis. In this embodiment, the to-be-joined metal member 1 is rotated so that the first metal member 1a is arranged on the left side with respect to the traveling direction of the main joining rotary tool F.
In addition, when rotating the rotation tool F for main joining counterclockwise, the to-be-joined metal member 1 is rotated so that the 1st metal member 1a may be arrange | positioned with respect to the advancing direction of the rotation tool F for main joining.

As shown in FIG. 10, the insertion depth of the stirring pin F2 is such that the tip of the protrusion F5 is a small diameter portion of the first metal member 1a while the flat surface F4 is in contact with the first metal member 1a and the second metal member 1b. 3 is set so as to be inserted deeper than the position of the outer peripheral surface 13a. That is, the flat surface F4 of the stirring pin F2 is separated from the outer peripheral surface 13a of the small diameter portion 3, and only the tip of the projection F5 is inserted into the outer peripheral surface 13a of the small diameter portion 3.
Then, as shown in FIG. 11, the main joining rotary tool F is moved relative to the metal member 1 to be joined along the abutting portion J1 in a state where it is maintained at a constant height. A plasticized region W is formed on the movement trajectory of the main rotating tool for welding F.

When the rotation tool F for main welding makes a round of the abutting portion J1, the first intermediate point s2 is passed through to the second intermediate point s3. As shown in FIG. 12, the end portion (termination Wb) of the plasticized region at the second intermediate point s3 is a portion that becomes “the end of the plasticized region formed in the butt portion” in the claims.
When the main welding rotary tool F reaches the second intermediate point s3, the rotation of the bonded metal member 1 around the axis is stopped. Then, the main joining rotary tool F is relatively moved to the end position (drawing position) e1 set on the first metal member 1a, and the main joining rotary tool F is detached from the metal member 1 to be joined.

  When the extraction trace of the main joining rotary tool F remains on the metal member 1 to be joined, for example, a repairing process for repairing by overlay welding may be performed.

  According to the friction stir welding method according to the present embodiment described above, as shown in FIG. 13, in the main joining step, the shoulder portion is not allowed to enter the first metal member 1a and the second metal member 1b as in the prior art. Therefore, the width of the plasticized region W can be made smaller than before, and the pressing force acting on the first metal member 1a and the second metal member 1b can be reduced. As a result, even if the thickness of the small diameter portion 3 (height of the outer peripheral surface 13a) is reduced, it is possible to prevent the metal material from flowing into the bonded metal member 1, thereby improving the degree of freedom in design. Can be made.

  Moreover, according to the friction stir welding method of this embodiment, since only the stirring pin F2 is inserted into the first metal member 1a and the second metal member 1b, the friction stirrer is compared with the case where the shoulder portion of the rotary tool is pushed in. Such a load can be reduced. Moreover, since the load concerning a friction stirrer can be reduced, the deep position of the butt | matching part J1 can be joined in the state which does not apply a big load to a friction stirrer.

  Further, according to the friction stir welding method of the present embodiment, the plastic fluid material that is frictionally stirred along the protrusion F5 of the stirring pin F2 and wound up on the protrusion F5 is pressed by the flat surface F4. Thereby, the periphery of the protrusion F5 can be reliably frictionally stirred, and an oxide film between the outer peripheral surface 13a of the small-diameter portion 3 of the first metal member 1a and the inner peripheral surface 13b of the second metal member 1b can be surely obtained. Therefore, the bonding strength of the butt J1 can be increased.

  Further, in the main joining step of the present embodiment, as shown in FIG. 12, the start end Wa and the end end Wb of the plasticized region W overlap and a part of the plasticized region W overlaps. The water tightness and air tightness of the part can be improved.

  Further, when the main rotating tool F is rotated to the right as in the present embodiment, there is a possibility that a bonding defect may occur on the left side in the advancing direction. It set so that the one metal member 1a might arrange | position. Thereby, even if a joint defect is formed, it is formed on the first metal member 1a side which is a solid member. That is, since a joint defect is formed at a position separated from the second metal member 1b, which is a hollow member, it is possible to suppress a decrease in watertightness and airtightness of the metal member 1 to be joined.

  Further, according to the friction stir welding method of the present embodiment, the main welding rotary tool F is moved to the first metal member 1a side with respect to the plasticizing region W, and the main welding rotary tool is moved on the first metal member 1a. In order to extract F, the extraction trace can be formed at a position far from the second metal member 1b which is a hollow member. Thereby, the fall of the watertightness of the to-be-joined metal member 1 and airtightness can be suppressed. Further, if the rotary tool F for main joining is moved to the second metal member 1b side from the plasticizing region W, the metal material may flow out into the metal member 1 to be joined. According to the method, this problem can be solved.

  In addition, by performing the temporary joining step before the main joining step, it is possible to prevent the first metal member 1a and the second metal member 1b from opening during the main joining step.

<Modification>
Next, a modified example of the present invention will be described.
As shown in FIG. 10, in the main joining step of the above-described embodiment, the friction stir welding was performed by setting the rotation center axis C of the main welding rotary tool F and the butting portion J1 to overlap each other. In the main joining process of the modified example, as shown in FIGS. 13 and 14, the friction stirrer is performed with the rotation center axis C of the main joining rotary tool F positioned on the first metal member 1a side with respect to the abutting portion J1. Join.

  As shown in FIG. 13, also in the main joining process, since the main welding rotary tool F is rotated to the right, the first metal member 1 a is arranged on the left side with respect to the traveling direction of the main welding rotary tool F. Set to Also in the main joining process according to the modified example, the butted portion J1 is frictionally stirred, and the first metal member 1a and the second metal member 1b are joined.

  According to the modification, there is a possibility that a bonding defect is formed on the left side in the traveling direction of the main rotating tool F for bonding, but the bonding defect can be formed on the first metal member 1a side which is a solid member. That is, the joint defect in the modified example is formed at a position further away from the second metal member 1b than in the above-described embodiment. Thereby, the fall of the watertightness of the to-be-joined metal member 1 and airtightness can be suppressed more.

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.
For example, the temporary joining step may be performed using the main joining rotating tool F. Moreover, you may perform a temporary joining process by welding.

  Moreover, in this embodiment, although the columnar member and the cylindrical member were joined, it is not limited to this. Other shapes may be used as long as they join a large-diameter portion and a columnar metal member provided with a small-diameter portion in the large-diameter portion and a cylindrical member.

  Moreover, in this embodiment, although the to-be-joined metal member 1 is rotated, the main-joining rotation tool F is moved relative to the butting portion J1, but the to-be-joined metal member 1 is not brought into rotation. The main joining rotary tool F may be moved with respect to the part J1.

  Moreover, in this embodiment, although the main welding rotation tool F is rotated to the right, it may be rotated to the left. In this case, it sets so that the 1st metal member 1a may be arrange | positioned at the advancing direction right side of this rotation tool F for this joining. By setting in this way, an effect equivalent to that of the embodiment can be obtained.

  Moreover, in this embodiment, although this rotation tool F for this joining was made to make one round with respect to the butt | matching part J1, you may make it make two or more rounds. By making two rounds, the joint defect generated in the first round can be frictionally stirred again, so that watertightness and airtightness can be improved. Further, after the second round, the friction stirring may be performed while shifting the main welding rotary tool F toward the first metal member 1a. By doing in this way, a joint defect can be repaired reliably.

  Moreover, when the main joining process is completed, a burr cutting process for cutting off burrs appearing on the surface of the metal member 1 to be joined may be performed.

DESCRIPTION OF SYMBOLS 1 Metal member to be joined 1a 1st metal member 1b 2nd metal member 2 Large diameter part 3 Small diameter part C Rotation center axis D Rotation main axis F Rotating tool for rotation (rotary tool)
F1 connecting portion F2 stirring pin F4 flat surface F5 protrusion G rotating tool for temporary joining J1 abutting portion W plasticizing region Wa start end Wb end

Claims (7)

A columnar first metal member having a small-diameter portion at the end of the large-diameter portion and a cylindrical second metal member having an outer diameter substantially equal to the large-diameter portion are formed by abutting each other at the end surfaces. A friction stir welding method for performing friction stir using a rotary tool equipped with a stirrer pin against the butted portion of the metal member to be joined,
The rotating tool includes a flat surface that is formed at a tip portion of the stirring pin and is perpendicular to the rotation axis of the rotating tool, and a protrusion that protrudes from the flat surface,
Only the agitation pin is inserted into the abutting portion, and the tip of the protruding portion is placed on the outer peripheral surface of the small diameter portion of the first metal member while the flat surface is in contact with the first metal member and the second metal member. A friction stir welding method, wherein the rotating tool is rotated around the metal member to be joined in a state of being inserted deeper than the position.   2. The friction stir welding method according to claim 1, wherein a start end and an end of a plasticized region formed in the butt portion overlap each other, and a part of the plasticized region overlaps.   The rotating tool is rotated around the metal member to be joined in a state where the rotation center axis of the rotating tool is positioned on the first metal member side with respect to the abutting portion. Item 3. The friction stir welding method according to Item 2. When the first metal member is located on the left side in the traveling direction of the rotary tool, rotate the rotary tool to the right,
4. The friction stir welding method according to claim 1, wherein when the first metal member is positioned on the right side in the traveling direction of the rotary tool, the rotary tool is rotated counterclockwise.   The rotary tool is moved toward the first metal member from the end of the plasticizing region formed in the abutting portion, and the drawing position of the rotary tool is provided in the first metal member. The friction stir welding method according to any one of claims 1 to 4.   Prior to the step of friction stir welding with the rotary tool, a part of the butting portion is temporarily joined using a rotary tool for temporary joining that is smaller than the rotary tool. The friction stir welding method according to any one of the above. A first metal member having a cylindrical small-diameter portion at the end of a cylindrical large-diameter portion and a cylindrical second metal member having an outer diameter substantially equal to the large-diameter portion are abutted against each other. A friction stir welding method for performing friction stir using a rotary tool provided with a stirring pin for the butted portion of the metal member to be joined formed by:
The rotating tool includes a flat surface that is formed at a tip portion of the stirring pin and is perpendicular to a rotation axis of the rotating tool, and a protrusion that protrudes from the flat surface.
Only the agitation pin is inserted into the abutting portion, and the tip of the protruding portion is placed on the outer peripheral surface of the small diameter portion of the first metal member while the flat surface is in contact with the first metal member and the second metal member. A friction stir welding method, wherein the rotating tool is rotated around the metal member to be joined in a state of being inserted deeper than the position.

Images