JP7140062B2 - Friction stir welding method - Google Patents

Description

The present invention relates to a friction stir welding method.

For example, Patent Literature 1 discloses an invention in which a cylindrical first metal member and a cylindrical second metal member are friction stir welded using a rotating tool. FIG. 14 is a cross-sectional view showing a conventional friction stir welding method.

As shown in FIG. 14, in the conventional friction stir welding method, a butt portion J10 formed by butting the first metal member 101 and the second metal member 102 is friction stir welded. The rotary tool G has a cylindrical shoulder G1 and an agitating pin G2. The first metal member 1 is formed with a stepped side surface 101a and a stepped bottom surface 101b. The abutting portion J10 is formed by abutting the stepped bottom surface 101b of the first metal member 101 and the end surface 102a of the second metal member 102 against each other.

JP 2009-269058 A

Here, in some cases, the first metal member 101 is made of cast material of 4000 series aluminum alloy, and the second metal member 102 is made of wrought material of 1000 series aluminum alloy. In other words, friction stir welding may be performed between aluminum alloy members of different grades.

For example, when the first metal member 101 is made of a cast material and the second metal member 102 is made of a wrought material, compared to the material resistance that the stirring pin G2 receives from the second metal member 102 side, the first metal member The material resistance received from the 101 side increases. Therefore, it becomes difficult to stir different types of materials with the stirring pin G2 of the rotary tool G in a well-balanced manner, and there is a problem that void defects occur in the plasticized region after bonding, resulting in a decrease in bonding strength.

From such a point of view, an object of the present invention is to provide a friction stir welding method capable of suitably joining different kinds of aluminum alloys.

In order to solve the above problems, the present invention provides 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 inner diameter substantially equal to that of the small diameter portion. A friction stir welding method in which friction stir is performed using a rotating tool having a proximal side pin and a distal side pin with respect to the butted portion of the metal member to be welded, which is formed by butting the ends of the first The metal member is made of a first aluminum alloy, the second metal member is made of a second aluminum alloy, and the first aluminum alloy is a material having higher hardness than the second aluminum alloy, A taper angle of the proximal pin is larger than a taper angle of the distal pin, and a stepped pin stepped portion is formed on an outer peripheral surface of the proximal pin, and the second metal By inserting the small-diameter portion of the first metal member into the opening of the member, the inner peripheral surface of the second metal member and the stepped side surface of the first metal member overlap each other, and the second metal member a butting step of butting the end face and the step inclined surface of the first metal member to form a gap having a V-shaped cross section in the butting portion; so that the outer peripheral surface of the distal side pin is slightly in contact with the step inclined surface of the first metal member, and the outer peripheral surface of the proximal side pin is brought into contact with the outer peripheral surface of the second metal member. In this state, the outer peripheral surface of the second metal member is moved to a predetermined depth along a set movement route set on the second metal member side of the abutment portion while allowing the second aluminum alloy to flow into the gap. and a final joining step of friction-stirring the butt portion by making one turn around the joint.

Further, in the present invention, a cylindrical first metal member having a small diameter portion at the end of a large diameter portion and a cylindrical second metal member having an inner diameter substantially equal to that of the small diameter portion are butted against each other. A friction stir welding method in which friction stir is performed using a rotating tool having a proximal end pin and a distal end pin against the butted portion of the metal members to be welded formed by the first aluminum alloy wherein the second metal member is made of a second aluminum alloy, the first aluminum alloy is a grade with higher hardness than the second aluminum alloy, and the taper of the proximal pin The angle is larger than the taper angle of the distal pin, and a stepped pin stepped portion is formed on the outer peripheral surface of the proximal pin, and the opening of the second metal member is provided with the first taper. By inserting the small diameter portion of one metal member, the inner peripheral surface of the second metal member and the stepped side surface of the first metal member are overlapped, and the end surface of the second metal member and the first metal member a butting step of forming a V-shaped cross-sectional gap in the abutting portion by abutting the step inclined surface of the rotating tool, inserting the tip pin of the rotating tool into the outer peripheral surface of the second metal member, and inserting the tip While the outer peripheral surface of the side pin is slightly in contact with the step inclined surface of the first metal member, and the outer peripheral surface of the base end side pin is in contact with the outer peripheral surface of the second metal member, the gap is filled with While flowing the second aluminum alloy, it is made to go around the outer peripheral surface of the second metal member at a predetermined depth along a set movement route set on the second metal member side of the abutting portion. and a final joining step of friction-stirring the butted portion.

According to this joining method, the second aluminum alloy mainly on the side of the second metal member in the butted portion is agitated and plastically fluidized by frictional heat between the second metal member and the pin on the distal end side, and the first metal member and the first metal member in the butted portion are agitated. The second metal member can be joined. In addition, since the outer peripheral surface of the pin on the distal end side is only slightly in contact with the step inclined surface of the first metal member, it is possible to minimize the mixing of the first aluminum alloy from the first metal member into the second metal member. . As a result, mainly the second aluminum alloy on the side of the second metal member is friction-stirred at the butted portion, so that a decrease in joint strength can be suppressed. In addition, since the friction stir is performed while the outer peripheral surface of the proximal pin is in contact with the outer peripheral surface of the second metal member, the occurrence of burrs can be suppressed.

Moreover, it is preferable that the starting end and the terminal end of the plasticized region formed in the butted portion overlap, and that a part of the plasticized region overlaps.

According to such a joining method, the watertightness and airtightness of the metal member to be joined can be enhanced.

Moreover, it is preferable that the outer diameter of the second metal member is larger than the outer diameter of the large diameter portion of the first metal member.

According to such a joining method, it is possible to prevent the joining portion from becoming short of metal.

Further, when the first metal member is positioned on the left side in the traveling direction of the rotating tool, the rotating tool is rotated to the right, and when the first metal member is positioned on the right side in the traveling direction of the rotating tool, the rotating tool is rotated. Left rotation is preferable.

According to such a joining method, friction stir is promoted in the butt portion side of the plasticized region, and joining can be performed more preferably.

Further, in the main joining step, the rotating tip side pin is inserted from the start position set on the set movement route, and the tip side pin is gradually pushed in until it reaches a predetermined depth while moving in the advancing direction. is preferred.
Further, in the main joining step, after inserting the rotating tip side pin into a start position set further away from the first metal member than the set movement route, the rotation center axis of the rotating tool is set to the above It is preferable that the tip side pin is gradually pushed in until reaching the predetermined depth while being moved to a position that overlaps with the set movement route.

According to this joining method, when inserting the rotating tool, it is possible to prevent the frictional heat from becoming excessive on the set movement route, and the first aluminum alloy from the first metal member side to the second metal member side contamination can be prevented.

Further, in the main welding step, an end position is set on the set movement route, and after the friction stir at the butted portion, the tip side pin is gradually pulled out while moving the rotating tool to the end position. Preferably, the rotary tool is disengaged from the second metal member at the end position.
Further, in the main welding step, an end position is set on a side further away from the first metal member than the set movement route, and after friction stir at the butted portion, the rotating tool is moved to the end position. It is preferable to remove the rotating tool from the second metal member at the end position by gradually withdrawing the pin on the distal end side.

According to this joining method, when the rotating tool is separated, it is possible to prevent the frictional heat from becoming excessive on the set movement route, and the first aluminum alloy from the first metal member side to the second metal member side can be prevented. contamination can be prevented.

Further, in the main joining step, it is preferable that friction stir is performed on the butted portion in a state in which the tip of the tip side pin penetrates the stepped side surface of the first metal member.

According to this joining method, the joining strength between the first metal member and the second metal member can be further increased.

According to the friction stir welding method according to the present invention, aluminum alloys of different types can be suitably welded.

1 is a side view of a rotary tool according to an embodiment of the invention; FIG. FIG. 4 is an enlarged cross-sectional view of the rotary tool; It is a cross-sectional view showing a first modification of the rotary tool. It is a sectional view showing the second modification of the rotation tool. It is a sectional view showing the third modification of a rotation tool. BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the friction stir welding method which concerns on 1st embodiment of this invention. It is a perspective view which shows the 1st metal member and 2nd metal member of the friction stir welding method which concerns on 1st embodiment. It is sectional drawing which shows the butt|matching process of the friction stir welding method which concerns on 1st embodiment. It is a perspective view which shows the butt|matching process of the friction stir welding method which concerns on 1st embodiment. It is a perspective view which shows the main joining process of the friction stir welding method which concerns on 1st embodiment. FIG. 4 is a cross-sectional view showing the main joining step of the friction stir welding method according to the first embodiment; FIG. 5 is a perspective view showing the main joining step of the friction stir welding method according to the second embodiment of the present invention; FIG. 5 is a perspective view showing the main joining step of the friction stir welding method according to the second embodiment of the present invention; It is a cross-sectional view showing a conventional friction stir welding method.

Embodiments of the present invention will be described with reference to the drawings as appropriate. First, the rotary tool used in the joining method according to this embodiment will be described. A rotating tool is a tool used for friction stir welding. As shown in FIG. 1, the rotating tool F is made of, for example, tool steel, and is mainly composed of a base shaft portion F1, a proximal pin F2, and a distal pin F3. The base shaft portion F1 has a cylindrical shape and is a portion connected to the main shaft of the friction stirrer.

The base end pin F2 is continuous with the base shaft portion F1 and tapers toward the tip. The proximal pin F2 has a truncated cone shape. The taper angle A of the proximal pin F2 may be set appropriately, and is, for example, 135 to 160°. If the taper angle A is less than 135° or exceeds 160°, the joint surface roughness after friction stir increases. The taper angle A is larger than the taper angle B of the distal pin F3, which will be described later. As shown in FIG. 2, a stepped pin stepped portion F21 is formed over the entire height direction on the outer peripheral surface of the base end side pin F2. The pin stepped portion F21 is spirally formed clockwise or counterclockwise. That is, the pin stepped portion F21 has a spiral shape when viewed from above, and has a stepped shape when viewed from the side. In the first embodiment, the pin stepped portion F21 is set counterclockwise from the base end side to the tip end side in order to rotate the rotary tool F right.

When rotating the rotating tool F to the left, it is preferable to set the pin stepped portion F21 clockwise from the proximal side to the distal side. As a result, the plastic flow material is guided to the tip end side by the pin stepped portion F21, so that the amount of metal overflowing to the outside of the metal members to be joined can be reduced. The pin step portion F21 is composed of a step bottom surface F21a and a step side surface F21b. The distance X1 (horizontal distance) between the vertices F21c, F21c of the adjacent pin stepped portions F21 is appropriately set according to the stepped angle C and the height Y1 of the stepped side surface F21b, which will be described later.

The height Y1 of the stepped side surface F21b may be set as appropriate, and is set to 0.1 to 0.4 mm, for example. If the height Y1 is less than 0.1 mm, the joint surface roughness becomes large. On the other hand, when the height Y1 exceeds 0.4 mm, the joint surface roughness tends to increase, and the number of effective stepped portions (the number of pin stepped portions F21 in contact with the metal members to be joined) also decreases.

The step angle C between the step bottom surface F21a and the step side surface F21b may be set appropriately, but is set to 85 to 120°, for example. The stepped bottom surface F21a is parallel to the horizontal plane in this embodiment. The stepped bottom surface F21a may be inclined in the range of −5° to 15° with respect to the horizontal plane toward the outer peripheral direction from the rotation axis of the tool (minus is downward with respect to the horizontal plane, plus is with respect to the horizontal plane above). The distance X1, the height Y1 of the stepped side surface F21b, the stepped angle C, and the angle of the stepped bottom surface F21a with respect to the horizontal plane are such that the plastic flow material does not stay inside the pin stepped portion F21 and adhere to the outside when performing friction stir. In addition, the step bottom F21a presses the plastic flow material to reduce the joint surface roughness.

As shown in FIG. 1, the distal pin F3 is formed continuously with the proximal pin F2. The distal pin F3 has a truncated cone shape. The distal end of the distal pin F3 forms a flat surface F4 perpendicular to the rotation axis. A taper angle B of the distal pin F3 is smaller than a taper angle A of the proximal pin F2. As shown in FIG. 2, a spiral groove F31 is engraved on the outer peripheral surface of the tip side pin F3. The spiral groove F31 may be either clockwise or counterclockwise, but in the first embodiment, it is engraved counterclockwise from the proximal side toward the distal side in order to rotate the rotary tool F clockwise.

In addition, when rotating the rotating tool F counterclockwise, it is preferable to set the spiral groove F31 clockwise from the base end side to the tip end side. As a result, the plastic flow material is guided to the tip side by the spiral groove F31, so that the amount of metal overflowing to the outside of the metal members to be joined can be reduced. The spiral groove F31 is composed of a spiral bottom surface F31a and a spiral side surface F31b. The distance (horizontal distance) between the apexes F31c, F31c of the adjacent spiral grooves F31 is defined as length X2. Let the height of the spiral side surface F31b be a height Y2. A spiral angle D formed by the spiral bottom surface F31a and the spiral side surface F31b is, for example, 45 to 90°. The spiral groove F31 has the role of increasing the frictional heat by coming into contact with the metal members to be joined and guiding the plastic flow material to the tip side. Further, the rotary tool F may be attached to a robot arm having a rotary drive means such as a spindle unit at its tip.

The design of the rotary tool F can be changed as appropriate. FIG. 3 is a side view showing a first modification of the rotary tool of the invention. As shown in FIG. 3, in the rotary tool FA according to the first modified example, the step angle C between the step bottom surface F21a and the step side surface F21b of the pin step portion F21 is 85°. The stepped bottom surface F21a is parallel to the horizontal plane. In this way, the stepped bottom surface F21a is parallel to the horizontal surface, and the stepped angle C may be an acute angle within a range in which the plastic flow material stays and adheres to the pin stepped portion F21 during friction stirring and escapes to the outside. .

FIG. 4 is a side view showing a second modification of the rotary tool of the invention. As shown in FIG. 4, in the rotary tool FB according to the second modification, the step angle C of the pin step portion F21 is 115°. The stepped bottom surface F21a is parallel to the horizontal plane. In this manner, the stepped bottom surface F21a may be parallel to the horizontal plane, and the stepped angle C may be an obtuse angle within the range of functioning as the pin stepped portion F21.

FIG. 5 is a side view showing a third modification of the rotary tool of the invention. As shown in FIG. 5, in the rotary tool FC according to the third modification, the stepped bottom surface F21a is inclined upward by 10° with respect to the horizontal plane from the rotation axis of the tool toward the outer peripheral direction. The stepped side surface F21b is parallel to the vertical plane. In this manner, the stepped bottom surface F21a may be formed so as to be inclined upward from the horizontal surface toward the outer peripheral direction from the rotating shaft of the tool within a range where the plastic flow material can be pressed during friction stirring. The first to third modifications of the rotating tool described above can also produce effects equivalent to those of the following embodiments.

[First embodiment]
A first embodiment of the present invention will be described with reference to the drawings as appropriate. In the friction stir welding method according to this embodiment, as shown in FIG. 6, the first metal member 1 and the second metal member 2 are friction stir welded. The first metal member 1 and the second metal member 2 are also collectively called a metal member H to be joined. In the friction stir welding method according to this embodiment, a preparatory step, a butting step, and a main welding step are performed.

The preparation step is a step of preparing the first metal member 1 and the second metal member 2 . As shown in FIG. 7 , the first metal member 1 is a solid metal member having a large diameter portion 11 and a small diameter portion 12 . The first metal member 1 is not particularly limited as long as it is a metal that can be friction-stirred, but in this embodiment it is formed mainly of a first aluminum alloy. As the first aluminum alloy, for example, an aluminum alloy cast material such as JISH5302 ADC12 (Al-Si-Cu system) is used.

The large diameter portion 11 has a cylindrical shape. The small-diameter portion 12 has a columnar shape and is concentrically formed on the distal end side of the large-diameter portion 11 . A step portion 13 is formed by the large diameter portion 11 and the small diameter portion 12 . The step portion 13 is composed of a step inclined surface 13a and a step side surface 13b. As shown in FIG. 8, the step inclined surface 13a is inclined in a direction away from the second metal member 2 toward the outer diameter direction. The inclination angle β of the step inclined surface 13a is the same as the inclination angle α (see FIG. 1) of the distal pin F3. The stepped side surface 13 b is perpendicular to the end surface 12 a of the small diameter portion 12 . That is, the stepped side surface 13b is parallel to the axial direction of the first metal member 1. As shown in FIG.

The second metal member 2 is a cylindrical metal member. Although it is not particularly limited as long as it is a metal that can be friction-stirred, in the present embodiment, it is formed mainly containing a second aluminum alloy. The second aluminum alloy is a material with a lower hardness than the first aluminum alloy. The second aluminum alloy is made of, for example, an aluminum alloy wrought material such as JIS A1050, A1100, A6063. The end surface 21a of the second metal member 2 is perpendicular to the outer peripheral surface 21b and the inner peripheral surface 21c. The outer diameter of the first metal member 1 and the outer diameter of the second metal member 2 may be the same. ing. In addition, the outer diameter of the inner peripheral surface 21c of the second metal member 2 is the same or substantially the same as the outer diameter of the small diameter portion 12 of the first metal member 1 .

The butting step is a step of butting the end of the first metal member 1 and the end of the second metal member 2, as shown in FIG. In the butting step, the small diameter portion 12 of the first metal member 1 is inserted into the opening of the second metal member 2 . As a result, the step inclined surface 13a of the first metal member 1 and the end surface 21a of the second metal member 2 are butted together to form a butt portion J1. A gap having a V-shaped cross section is formed in the butted portion J1 in the circumferential direction. Moreover, the stepped side surface 13b of the first metal member 1 and the inner peripheral surface 21c of the second metal member 2 are overlapped to form a butt portion J2.

As shown in FIG. 9, a set movement route L1 is set on the outer peripheral surface 21b of the second metal member 2. As shown in FIG. The set movement route L1 is set closer to the second metal member 2 than the abutting portion J1, and is parallel to the abutting portion J1. The set movement route L1 is a movement route of the rotary tool F necessary for joining the butt portion J1 in the main joining process described later. The set travel route L1 will be described later in detail.

10 and 11, the main welding step is a step of friction stir welding the butted portion J1 using a rotating tool F. FIG. In the main welding process, the rotating tool F may be fixed and the metal member H to be welded may be rotated in the circumferential direction, or the metal member H to be welded may be fixed and the rotating tool F may be rotated around the metal member H to be welded. You can move it.

As shown in FIG. 10, in the main joining step, there are a push-in section from the starting position SP1 to the intermediate point S1, a main section from the intermediate point S1 on the set movement route L1 to the intermediate point S2, and an intermediate point S2. to the end position EP1 are continuously friction stir welded. The intermediate points S1 and S2 are set on the set movement route L1. The start position SP1 is set on the outer peripheral surface 21b of the second metal member 2 on the side farther from the first metal member 1 than the set movement route L1. In this embodiment, the angle between the line segment connecting the start position SP1 and the intermediate point S1 and the set movement route L1 is set to be an obtuse angle.

In the pressing section of the main joining step, as shown in FIGS. 10 and 11, friction stir is performed from the start position SP1 to the intermediate point S1. In the push-in section, while the rotation center axis Z is perpendicular to the outer peripheral surface 21b, the tip side pin F3 rotated to the right is inserted into the start position SP1 and moved to the intermediate point S1. In other words, the center axis of rotation Z is set so as to overlap the normal line of the outer peripheral surface 21b of the second metal member 2 while the rotating tool F relatively moves. At this time, as shown in FIG. 10, the tip side pin F3 is gradually pushed in so as to reach a preset "predetermined depth" at least until reaching the intermediate point S1. In other words, the rotating tool F is gradually lowered while being moved along the set movement route L1 without remaining in one place.

Further, the outer peripheral surface of the tip end side pin F3 and the step inclined surface 13a of the first metal member 1 are set so as to be slightly in contact with each other when the intermediate point S1 is reached. Further, the flat surface F4 of the distal pin F3 is set to pass through the stepped side surface 13b while the outer peripheral surface of the proximal pin F2 and the outer peripheral surface 21b of the second metal member 2 are set to be in contact with each other. Then, the friction stir welding of this section is performed as it is.

A contact margin (offset amount) N between the outer peripheral surface of the tip-side pin F3 and the step inclined surface 13a of the first metal member 1 is set, for example, within a range of 0<N≦1.0 mm, preferably 0<N≦1.0 mm. It is set between 0.85 mm, more preferably between 0<N≦0.65 mm.

The set movement route L1, as shown in FIG. 11, indicates a locus through which the center of the flat surface F4 of the distal pin F3 passes. In other words, the set movement route L1 is set so that the step inclined surface 13a of the first metal member 1 and the outer peripheral surface of the tip end side pin F3 are parallel to each other in the circumferential direction of the butted portion J1 and are slightly in contact with each other. there is

In this section, the rotary tool F is relatively moved so that the center of the flat surface F4 overlaps the set movement route L1 when viewed from above (when viewed from the outer peripheral surface 21b side). In this section, friction stir welding is performed while allowing the second aluminum alloy of the second metal member 2 to flow into the gap of the butt portion J1. If the outer peripheral surface of the tip side pin F3 and the step inclined surface 13a are set so as not to come into contact with each other, the joining strength of the butted portion J1 is lowered. On the other hand, when the contact margin N between the outer peripheral surface of the tip side pin F3 and the step inclined surface 13a exceeds 1.0 mm, a large amount of the first aluminum alloy of the first metal member 1 is mixed into the second metal member 2 side. Poor bonding may occur.

In this section, as shown in FIG. 6, when the tip side pin F3 reaches the intermediate point S2 by rotating the rotating tool F once, the process proceeds to the detachment section. In the detachment section, the tip pin F3 is gradually moved upward from the intermediate point S2 to the end position EP1, and is detached from the second metal member 2 at the end position EP1. In other words, the rotating tool F is gradually pulled out in a direction away from the second metal member 2 while being moved to the end position EP1 without stopping the rotating tool F at one place. The end position EP1 is set at a position where the angle formed by the line segment connecting the end position EP1 and the intermediate point S2 and the set movement route L1 is an obtuse angle. A plasticized region W is formed in the movement trajectory of the rotating tool F. As shown in FIG.

According to the friction stir welding method of the present embodiment described above, the frictional heat between the second metal member 2 and the tip end pin F3 stirs mainly the second aluminum alloy on the second metal member 2 side of the butted portion J1. It is plastically fluidized, and the step inclined surface 13a of the first metal member 1 and the end surface 21a of the second metal member 2 can be joined at the abutting portion J1.

In addition, in order to keep the outer peripheral surface of the tip side pin F3 of the tip side pin F3 in slight contact with the step inclined surface 13a of the first metal member 1, the first aluminum from the first metal member 1 to the second metal member 2 is Mixing of the alloy can be reduced as much as possible. As a result, mainly the second aluminum alloy on the side of the second metal member 2 is friction-stirred at the butted portion J1, so that a decrease in joint strength can be suppressed. That is, in the main joining step, the imbalance in the material resistance received by the distal end pin F3 can be minimized between one side and the other side with respect to the rotation center axis Z of the distal end side pin F3. As a result, the plastic flow material is friction-stirred in a well-balanced manner, so that a decrease in bonding strength can be suppressed.

In addition, in the main joining process, by setting the position of the rotating tool F so that the outer peripheral surface of the tip side pin F3 and the step inclined surface 13a of the first metal member 1 are parallel to each other, the tip side pin F3 and the first Contact with the metal member 1 can be achieved in a well-balanced manner. Further, by setting the outer diameter of the second metal member 2 to be larger than the outer diameter of the first metal member 1, it is possible to prevent metal shortage at the joint. Further, by setting the tip of the tip side pin F3 so as to reach the stepped side surface 13b of the first metal member 1, the butted portion J2 can also be reliably friction-stirred, so that the bonding strength can be increased.

In addition, in the present embodiment, in the main joining step, the outer peripheral surface of the base end pin F2 and the outer peripheral surface 21b of the second metal member 2 are brought into contact with each other, and friction stir is performed while the plastic flow material is pressed. can be suppressed. In addition, since the plastic flow material can be pressed by the outer peripheral surface of the proximal pin F2, the step recesses formed on the joining surfaces (the outer peripheral surface 11b of the first metal member 1 and the outer peripheral surface 21b of the second metal member 2) It is possible to reduce the size of the groove and eliminate or reduce the bulging portion formed on the side of the stepped groove. Further, since the stepped pin stepped portion F21 of the base end pin F2 is shallow and has a wide outlet, the plastic flowable material is easily pulled out of the pin stepped portion F21 while the stepped bottom face F21a holds down the plastic flowable material. there is Therefore, even if the base end pin F2 presses the plastic flow material, the plastic flow material is less likely to adhere to the outer peripheral surface of the base end pin F2. Therefore, the joint surface roughness can be reduced, and the joint quality can be preferably stabilized.

Here, when inserting the tip side pin F3 into the set movement route L1, if the tip side pin F3 is pushed in the vertical direction to a predetermined depth, the frictional heat at the start position of friction stir becomes excessive. As a result, the metal on the side of the first metal member 1 tends to mix with the side of the second metal member 2 at the starting position, which causes a problem of poor bonding.

On the other hand, in the pushing-in section of the main joining step of the present embodiment, while moving the rotary tool F from the starting position SP1 to a position overlapping the set movement route L1, the tip-side pin F3 is gradually pushed in until reaching a predetermined depth. By doing so, it is possible to prevent the rotary tool F from stopping on the set movement route L1 and causing the frictional heat to locally become excessively large.
Similarly, in the detachment section of the main joining process, while moving the rotary tool F from the set movement route L1 to the end position EP1, the distal end side pin F3 is gradually pulled out from a predetermined depth to be detached. It is possible to prevent the rotary tool F from stopping at the top and the frictional heat from becoming excessive locally.

As a result, it is possible to prevent the frictional heat from becoming excessive on the set movement route L1 and the excessive mixing of the first aluminum alloy from the first metal member 1 to the second metal member 2, resulting in poor bonding.

In addition, in the main joining step, the positions of the start position SP1 and the end position EP1 may be appropriately set, but the angle formed between the start position SP1 and the set movement route L1 and the angle formed between the end position EP1 and the set movement route L1 are By setting the obtuse angle, the movement speed of the rotating tool F does not decrease at the intermediate points S1 and S2, and the transition to the main section or the detachment section can be performed smoothly. As a result, it is possible to prevent frictional heat from becoming excessive due to the rotation tool F stopping or moving at a reduced speed on the set movement route L1. Note that the rotary tool F may be moved from the start position SP1 to the set movement route L1 so that the trajectory of the rotary tool F draws an arc when viewed from above. Similarly, the rotary tool F may be moved from the set movement route L1 to the end position EP1 so that the trajectory of the rotary tool F draws an arc when viewed from above.

In addition, in the main joining process of the present embodiment, the rotation direction and the traveling direction of the rotary tool F may be appropriately set. The direction of rotation and the direction of travel of the rotating tool F were set so that the (butted portion J1 side) was on the shear side and the second metal member 2 side was on the flow side. By setting the first metal member 1 side to be the shear side, the agitation action by the tip side pin F3 around the butt portion J1 is enhanced, and the temperature rise at the butt portion J1 can be expected, and the first metal member 1 is expected to increase in the butt portion J1. The step inclined surface 13a of the member 1 and the end surface 21a of the second metal member 2 can be joined more reliably.

The shear side (Advancing side) means the side where the relative velocity of the outer circumference of the rotating tool with respect to the part to be welded is the sum of the tangential velocity at the outer circumference of the rotating tool and the moving velocity. . On the other hand, the flow side (retreating side) refers to the side where the relative speed of the rotating tool with respect to the parts to be welded becomes low due to the rotation of the rotating tool in the direction opposite to the moving direction of the rotating tool.

Moreover, the first aluminum alloy of the first metal member 1 is a material with higher hardness than the second aluminum alloy of the second metal member 2 . Thereby, the durability of the metal member H to be joined can be improved. Moreover, it is preferable that the first aluminum alloy of the first metal member 1 is a cast aluminum alloy material, and the second aluminum alloy of the second metal member 2 is a wrought aluminum alloy material. Castability, strength, machinability, etc. of the first metal member 1 can be enhanced by using, for example, an Al--Si--Cu-based aluminum alloy cast material such as JISH5302 ADC12 as the first aluminum alloy. Further, by using, for example, JIS A1000 series or A6000 series as the second aluminum alloy, workability and thermal conductivity can be enhanced.

In addition, in the main welding step, since the entire circumference of the butted portion J1 is friction stir welded, the airtightness and watertightness of the metal member H to be welded can be enhanced. Also, at the end portion of the main joining process, the rotating tool F is made to head toward the end position EP1 after completely passing the intermediate point S1. That is, by overlapping the ends of the plasticized regions W formed by the main bonding step, the airtightness and watertightness can be further improved.

In addition, in the main joining step, the rotating speed of the rotating tool F may be constant, but may be varied. In the pressing section of the main joining step, if the rotational speed of the rotating tool F at the start position SP1 is V1 and the rotational speed of the rotating tool F in this section is V2, V1>V2 may be satisfied. The rotation speed V2 is a preset constant rotation speed on the set movement route L1. In other words, at the start position SP1, the rotation speed may be set high, and the rotation speed may be gradually reduced in the push-in interval to shift to the main interval.

Further, in the detachment section of the main joining step, V3>V2 may be satisfied, where V2 is the rotational speed of the rotating tool F in this section and V3 is the rotational speed of the rotating tool F when detached at the end position EP1. That is, after shifting to the detachment section, the rotating tool F may be detached from the second metal member 2 while gradually increasing the rotation speed toward the end position EP1. When the rotating tool F is pushed into the second metal member 2 or separated from the second metal member 2, by setting as described above, the small pressing force in the pushing section or the separating section is compensated for by the rotation speed. Therefore, friction stirring can be performed favorably.

[Second embodiment]
Next, a friction stir welding method according to a second embodiment of the present invention will be described. As shown in FIGS. 12 and 13, the second embodiment differs from the first embodiment in that both the start position SP1 and the end position EP1 in the main joining step are set on the set movement route L1. In the second embodiment, the description will focus on the parts that are different from the first embodiment.

In manufacturing the liquid cooling jacket according to the second embodiment, a preparation process, a butting process, and a final joining process are performed. The preparation process and matching process are the same as in the first embodiment.

In the main joining step, as shown in FIG. 12, the starting position SP1 is set on the set movement route L1. In the main joining step, there is a push-in section from the starting position SP1 to the intermediate point S1, a main section from the intermediate point S1 on the set movement route L1 to the intermediate point S2 after going around once, and an end position EP1 from the intermediate point S2 (see FIG. 13). See), the three sections of the detachment section are continuously friction-stirred.

In the push-in section, as shown in FIG. 12, friction stir is performed from the start position SP1 to the intermediate point S1. In the push-in section, the tip side pin F3 rotated to the right is inserted into the starting position SP1 and moved to the intermediate point S1 while the rotation center axis Z is vertical. At this time, the tip side pin F3 is gradually pushed in so as to reach a preset "predetermined depth" at least until reaching the intermediate point S1. In other words, the rotating tool F is gradually lowered while being moved along the set movement route L1 without remaining in one place.

Further, in the push-in section, the outer peripheral surface of the tip end side pin F3 and the step inclined surface 13a of the first metal member 1 are set so as to slightly contact each other when the middle point S1 is reached. Further, the outer peripheral surface of the proximal pin F2 and the outer peripheral surface 21b of the second metal member 2 are set so as to be in contact with each other, and the flat surface F4 of the proximal pin F2 touches the stepped side surface 13b of the first metal member 1. Set to penetrate. While maintaining this posture of the rotating tool F, the friction stir welding of this section is performed as it is. The contact margin (offset amount) N between the outer peripheral surface of the distal pin F3 and the step inclined surface 13a of the first metal member 1 and the setting of the set movement route L1 are the same as in the first embodiment.

In this section, as shown in FIG. 13, the rotating tool F is made to go around along the set movement route L1. When the rotating tool F is made to go around once and the tip side pin F3 reaches the intermediate point S2, the transition is made to the detachment section. The end position EP1 is set on the set movement route L1. In the separation section, the tip side pin F3 is gradually pulled out from the intermediate point S2 to the end position EP1, and the tip side pin F3 is separated from the second metal member 2 at the end position EP1. In other words, the rotating tool F is gradually pulled out while being moved to the end position EP1 without remaining in one place.

The friction stir welding method according to the second embodiment described above can also achieve substantially the same effects as those of the first embodiment. As in the second embodiment, the start position SP1 and the end position EP1 in the main joining step may be set on the set movement route L1.

Although the embodiments of the present invention have been described above, design changes are possible as appropriate. For example, the first metal member 1 and the second metal member 2 may be columnar members having other cross-sectional shapes such as rectangular, polygonal, and elliptical. Also, both may be solid members, or both may be tubular members.

REFERENCE SIGNS LIST 1 first metal member 2 second metal member F rotary tool F2 proximal pin F3 distal pin F4 flat surface J1 butted portion SP1 start position EP1 end position W plastic region

Claims (10)

A first columnar metal member having a small diameter portion at the end of a large diameter portion and a second cylindrical metal member having an inner diameter substantially equal to that of the small diameter portion are butted together at their ends to be joined. A friction stir welding method in which friction stir is performed using a rotating tool having a proximal pin and a distal pin to a butted portion of a metal member,
The first metal member is made of a first aluminum alloy, the second metal member is made of a second aluminum alloy, and the first aluminum alloy has a higher hardness than the second aluminum alloy. and
A taper angle of the proximal pin is larger than a taper angle of the distal pin, and a stepped pin step portion is formed on an outer peripheral surface of the proximal pin,
By inserting the small-diameter portion of the first metal member into the opening of the second metal member, the inner peripheral surface of the second metal member and the stepped side surface of the first metal member are overlapped, and the abutting step of butting the end faces of the two metal members and the step inclined surface of the first metal member to form a gap having a V-shaped cross section at the butting portion;
The tip side pin of the rotating rotary tool is inserted into the outer peripheral surface of the second metal member, and the outer peripheral surface of the tip side pin is brought into slight contact with the step inclined surface of the first metal member. While the outer peripheral surface of the end-side pin is in contact with the outer peripheral surface of the second metal member, the second aluminum alloy is allowed to flow into the gap, and is set closer to the second metal member than the butt portion. A friction stir welding method, comprising: a main welding step of friction-stirring the butted portion by making a circle around the outer peripheral surface of the second metal member at a predetermined depth along a set moving route. 2. The friction stir welding method according to claim 1, wherein a starting end and an end of the plasticized region formed in the butted portion are overlapped, and a part of the plasticized region is overlapped. 3. The friction stir welding method according to claim 1, wherein the outer diameter of the second metal member is larger than the outer diameter of the large diameter portion of the first metal member. when the first metal member is located on the left side of the rotating tool in the direction of travel, rotating the rotating tool to the right;
The friction stir welding method according to any one of claims 1 to 3, wherein the rotating tool is rotated counterclockwise when the first metal member is positioned on the right side in the traveling direction of the rotating tool. In the main joining step, inserting the rotating tip side pin from a start position set on the set movement route, and gradually pushing the tip side pin until it reaches a predetermined depth while moving in the advancing direction. The friction stir welding method according to any one of claims 1 to 4. In the main joining step, after inserting the rotating tip-side pin into a start position set further away from the first metal member than the set movement route, the rotation center axis of the rotary tool is moved to the set movement. The friction stir welding method according to any one of claims 1 to 4, wherein the tip side pin is gradually pushed in until reaching the predetermined depth while being moved to a position overlapping the root. In the main welding step, an end position is set on the set movement route, and after the friction stir at the butted portion, the tip side pin is gradually pulled out while moving the rotary tool to the end position to reach the end position. The friction stir welding method according to any one of claims 1 to 6, wherein the rotating tool is separated from the second metal member at . In the main welding step, an end position is set on a side further away from the first metal member than the set movement route, and after friction stir for the butted portion, the rotating tool is moved to the end position while moving the The friction stir welding method according to any one of claims 1 to 6, wherein the tip side pin is gradually pulled out to separate the rotating tool from the second metal member at the end position. 9. The main welding step according to any one of claims 1 to 8, characterized in that friction stir is performed on the butted portion in a state in which the tip of the tip side pin penetrates the stepped side surface of the first metal member. Friction stir welding method according to claim 1. A first cylindrical metal member having a small diameter portion at the end of a large diameter portion and a second cylindrical metal member having an inner diameter substantially equal to that of the small diameter portion are butted against each other at their end surfaces to be joined. A friction stir welding method in which friction stir is performed using a rotating tool having a proximal end pin and a distal end pin with respect to a butted portion of a metal member,
The first metal member is made of a first aluminum alloy, the second metal member is made of a second aluminum alloy, and the first aluminum alloy has a higher hardness than the second aluminum alloy. and
A taper angle of the proximal pin is larger than a taper angle of the distal pin, and a stepped pin step portion is formed on an outer peripheral surface of the proximal pin,
By inserting the small-diameter portion of the first metal member into the opening of the second metal member, the inner peripheral surface of the second metal member and the stepped side surface of the first metal member are overlapped, and the a butting step of butting the end faces of the two metal members and the step inclined surface of the first metal member to form a gap having a V-shaped cross section at the butting portion;
The tip side pin of the rotating rotary tool is inserted into the outer peripheral surface of the second metal member, and the outer peripheral surface of the tip side pin is brought into slight contact with the step inclined surface of the first metal member. While the outer peripheral surface of the end-side pin is in contact with the outer peripheral surface of the second metal member, the second aluminum alloy is allowed to flow into the gap, and is set closer to the second metal member than the butt portion. A friction stir welding method, comprising: a main welding step of friction-stirring the butted portion by making a circle around the outer peripheral surface of the second metal member at a predetermined depth along a set moving route.

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