JP2021115588A - Frictional agitation joining method - Google Patents

Abstract

To provide a frictional agitation joining method capable of suitably joining aluminum alloys made of different kinds of material.SOLUTION: A frictional agitation joining method includes a permanent joining step of inserting a tip side pin F3 of a rotating rotary tool F into an outer peripheral surface 21b of a second metallic member 2, and frictionally agitating a butting part J1 by making one circuit around an outer peripheral surface 21b of the second metallic member 2 at a prescribed depth along a preset movement route L1 set closer to the second metallic member 2 side than to a butting part J1, while making a second aluminum alloy flow into a clearance with an outer peripheral surface of the tip side pin F3 in slight contact with a step difference inclined surface 13a of a first metallic member 1 while keeping an outer peripheral surface of a base end side pin F2 in contact with an outer peripheral surface of the second metallic member 2. In a desorption section of the permanent joining step, the tip side pin F3 is moved to an upper part of an inclined base 50 formed on an outer peripheral surface 11b of the first metallic member 1 and the tip side pin F3 is extracted. After the permanent joining step, the inclined base 50 is removed.SELECTED DRAWING: Figure 6

Description

The present invention relates to a friction stir welding method.

Friction stir welding is known as a technique for joining metal members to each other. Friction stir welding has a problem that a drawing hole remains when the stirring pin provided in the rotary tool is pulled out from the metal member. Therefore, a joining method is known in which a drawing hole is not left in the metal member. For example, in the friction stir welding method according to Patent Document 1, a method of reducing the drawing marks by gradually pulling out while moving the stirring pin is disclosed.

Japanese Unexamined Patent Publication No. 2016-87649

However, the friction stir welding method of Patent Document 1 has a problem that a drawing mark remains in the plasticized region when the rotating tool is gradually pulled out. Further, there is a problem that burrs are generated on the metal member after friction stir welding.
Therefore, it is an object of the present invention to provide a joining method capable of suppressing the occurrence of burrs and preventing the occurrence of pull-out holes and pull-out marks.

In order to solve the above problems, the present invention comprises a columnar first metal member having a small diameter portion at the end of the large diameter portion, and a tubular second metal member having an inner diameter substantially equal to that of the small diameter portion. This is a friction-stirring joining method in which friction-stirring is performed on the abutting portion of a metal member to be joined, which is formed by abutting the ends of the first metal member, and the first metal member is made of a first aluminum alloy. The second metal member is formed of a second aluminum alloy, the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy, and the rotary tool used for friction stirring is a base end side pin and a tip. A side pin is provided, and the taper angle of the base end side pin is larger than the taper angle of the tip end side pin, and a stepped pin step portion is formed on the outer peripheral surface of the base end side pin. The outer peripheral surface of the tip end side pin is inclined so as to be tapered, and is close to the boundary between the large diameter portion and the small diameter portion of the first metal member and protrudes from the outer peripheral surface of the first metal member. By inserting the small diameter portion of the first metal member into the opening of the second metal member in the preparatory step of forming the inclined table, the inner peripheral surface of the second metal member and the first metal member A butt step of superimposing the step side surface and abutting the end surface of the second metal member and the step inclined surface of the first metal member to form a gap having a V-shaped cross section in the butt portion, and the rotating rotation. The tip end side pin of the tool is inserted into the outer peripheral surface of the second metal member, and the outer peripheral surface of the tip end side pin is brought into contact with the outer peripheral surface of the second metal member while the outer peripheral surface of the base end side pin is brought into contact with the outer peripheral surface of the second metal member. Along the set movement route set on the second metal member side of the butt portion while flowing the second aluminum alloy into the gap in a state where the metal member is slightly in contact with the stepped inclined surface. The second metal member is made to go around the outer peripheral surface of the second metal member at a predetermined depth, and after frictional stirring is performed on the abutting portion, the tip side pin is moved so as to rise along the inclined surface of the inclined table. It is characterized by including a main joining step of pulling out on the upper side of the inclined surface and an inclined table removing step of removing the inclined table.

Further, in the present invention, a columnar first metal member having a small diameter portion at the end of a large diameter portion and a tubular second metal member having an inner diameter substantially equal to that of the small diameter portion are butted against each other. This is a friction-stirring joining method in which friction-stirring is performed on the abutting portion of the metal member to be joined, wherein the first metal member is made of a first aluminum alloy and the second metal member is a second metal member. It is made of two aluminum alloys, the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy, and the rotating tool used for friction stirring includes a base end side pin and a tip end side pin, and the above The taper angle of the base end side pin is larger than the taper angle of the tip end side pin, and a stepped pin step portion is formed on the outer peripheral surface of the base end side pin. The outer peripheral surface is inclined so as to be tapered, and a preparatory step of forming an inclined table that is close to the end surface of the second metal member and protrudes from the outer peripheral surface of the second metal member, and a preparatory step of forming the second metal member. By inserting the small diameter portion of the first metal member into the opening on the inclined table side, the inner peripheral surface of the second metal member and the stepped side surface of the first metal member are overlapped, and the second The abutting step of abutting the end surface of the metal member and the stepped inclined surface of the first metal member to form a gap having a V-shaped cross section in the abutting portion, and the tip side pin of the rotating tool is attached to the second metal. Inserted into the outer peripheral surface of the member, the outer peripheral surface of the tip end side pin is slightly brought into contact with the stepped inclined surface of the first metal member while the outer peripheral surface of the base end side pin is in contact with the outer peripheral surface of the second metal member. The second metal member is brought into contact with the second metal member at a predetermined depth along a set movement route set on the second metal member side of the butt portion while flowing the second aluminum alloy into the gap. After frictionally stirring the abutting portion around the outer peripheral surface of the metal, the tip side pin is moved so as to rise along the inclined surface of the inclined table and pulled out on the upper side of the inclined surface. It is characterized by including a step and a tilting table removing step of removing the tilting table.

Further, in the present invention, a columnar 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. This is a friction-stirring joining method in which friction-stirring is performed on the abutting portion of the metal member to be joined, wherein the first metal member is made of a first aluminum alloy and the second metal member is a second metal member. It is made of two aluminum alloys, the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy, and the rotating tool used for friction stirring includes a base end side pin and a tip end side pin, and the above The taper angle of the base end side pin is larger than the taper angle of the tip end side pin, and a stepped pin step portion is formed on the outer peripheral surface of the base end side pin. The outer peripheral surface is inclined so as to be tapered, and forms an inclined table that is close to the boundary between the large-diameter portion and the small-diameter portion of the first metal member and protrudes from the outer peripheral surface of the first metal member. By inserting the small diameter portion of the first metal member into the opening of the second metal member in the preparatory step, the inner peripheral surface of the second metal member and the stepped side surface of the first metal member are overlapped with each other. At the same time, a butt step of abutting the end surface of the second metal member and the stepped inclined surface of the first metal member to form a gap having a V-shaped cross section in the butt portion, and the tip side pin of the rotating tool. Is inserted into the outer peripheral surface of the second metal member, and the outer peripheral surface of the tip end side pin is brought into contact with the outer peripheral surface of the second metal member while the outer peripheral surface of the base end side pin is brought into contact with the outer peripheral surface of the first metal member. With the second aluminum alloy flowing into the gap in a state of being slightly in contact with the inclined surface, at a predetermined depth along the set movement route set on the second metal member side of the butt portion. After frictionally stirring the abutting portion around the outer peripheral surface of the second metal member, the tip side pin is moved so as to rise along the inclined surface of the inclined table to move the upper side of the inclined surface. It is characterized by including a main joining step of pulling out in the above step and a step of removing the tilting table to remove the tilting table.

Further, in the present invention, a columnar 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. This is a friction-stirring joining method in which friction-stirring is performed on the abutting portion of the metal member to be joined, wherein the first metal member is made of a first aluminum alloy and the second metal member is a second metal member. It is made of two aluminum alloys, the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy, and the rotating tool used for friction stirring includes a base end side pin and a tip end side pin, and the above The taper angle of the base end side pin is larger than the taper angle of the tip end side pin, and a stepped pin step portion is formed on the outer peripheral surface of the base end side pin. The outer peripheral surface is inclined so as to be tapered, and a preparatory step of forming an inclined table that is close to the end surface of the second metal member and protrudes from the outer peripheral surface of the second metal member, and a preparatory step of forming the second metal member. By inserting the small diameter portion of the first metal member into the opening on the inclined table side, the inner peripheral surface of the second metal member and the stepped side surface of the first metal member are overlapped, and the second The abutting step of abutting the end surface of the metal member and the stepped inclined surface of the first metal member to form a gap having a V-shaped cross section in the abutting portion, and the tip side pin of the rotating tool is attached to the second metal. Inserted into the outer peripheral surface of the member, the outer peripheral surface of the tip end side pin is slightly brought into contact with the stepped inclined surface of the first metal member while the outer peripheral surface of the base end side pin is in contact with the outer peripheral surface of the second metal member. The second metal member is brought into contact with the second metal member at a predetermined depth along a set movement route set on the second metal member side of the butt portion while flowing the second aluminum alloy into the gap. After frictionally stirring the abutting portion around the outer peripheral surface of the metal, the tip side pin is moved so as to rise along the inclined surface of the inclined table and pulled out on the upper side of the inclined surface. It is characterized by including a step and a tilting table removing step of removing the tilting table.

According to the friction stir welding method according to the present invention, it is possible to suppress the generation of burrs and prevent the generation of pull-out holes and pull-out marks in the first metal member and the second metal member.

It is a side view which shows the rotation tool which concerns on embodiment of this invention. It is an enlarged sectional view of the rotation tool. It is sectional drawing which shows the 1st modification of a rotation tool. It is sectional drawing which shows the 2nd modification of the rotation tool. It is sectional drawing which shows the 3rd modification of the rotation tool. 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 the 2nd metal member of the friction stir welding method which concerns on 1st Embodiment. It is sectional drawing which shows the butt process of the friction stir welding method which concerns on 1st Embodiment. It is a perspective view which shows the butt 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. It is sectional drawing which shows this section of the main joining process of the friction stir welding method which concerns on 1st Embodiment. It is sectional drawing which shows the separation section of the main joining 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 2nd Embodiment. It is a perspective view which shows the preparation process of the friction stir welding method which concerns on the 1st modification. It is a perspective view which shows the friction stir of a closet section in the main joining process of the friction stir welding method which concerns on the 2nd modification.

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

The base end side pin F2 is continuous with the base shaft portion F1 and is tapered toward the tip end. The proximal end side pin F2 has a truncated cone shape. The taper angle A of the base end side pin F2 may be appropriately set, 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 welding becomes large. The taper angle A is larger than the taper angle B of the tip side pin F3, which will be described later. As shown in FIG. 2, a stepped pin step portion F21 is formed on the outer peripheral surface of the base end side pin F2 over the entire height direction. The pin step portion F21 is formed in a spiral shape in a clockwise or counterclockwise direction. That is, the pin step portion F21 has a spiral shape when viewed in a plane and a step shape when viewed from a side surface. When rotating the rotation tool F clockwise, it is preferable to set the pin step portion F21 counterclockwise from the base end side to the tip end side.

When rotating the rotation tool F counterclockwise, it is preferable to set the pin step portion F21 clockwise from the base end side to the tip end side. As a result, the plastic fluid material is guided to the tip side by the pin step portion F21, so that the metal that overflows to the outside of the metal member 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 and F21c of the adjacent pin step portions F21 is appropriately set according to the step angle C and the height Y1 of the step side surface F21b described later.

The height Y1 of the step side surface F21b may be appropriately set, and is set to, for example, 0.1 to 0.4 mm. 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 step portions (the number of pin step portions F21 in contact with the metal member to be joined) also decreases.

The step angle C formed by the step bottom surface F21a and the step side surface F21b may be appropriately set, but is set to, for example, 85 to 120 °. The step bottom surface F21a is parallel to the horizontal plane in this embodiment. The step bottom surface F21a may be inclined in the range of -5 ° to 15 ° with respect to the horizontal plane from the rotation center axis of the tool toward the outer peripheral direction (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 step side surface F21b, the step angle C, and the angle of the step bottom surface F21a with respect to the horizontal plane are such that the plastic fluid does not stay inside the pin step portion F21 and adhere to the outside during friction stir welding. The surface roughness of the joint is appropriately set so that the plastic fluid material can be pressed by the step bottom surface F21a to reduce the roughness of the joint surface.

As shown in FIG. 1, the distal end side pin F3 is continuously formed on the proximal end side pin F2. The tip side pin F3 has a truncated cone shape. The tip of the tip side pin F3 is a flat surface F4 perpendicular to the rotation center axis. The taper angle B of the tip end side pin F3 is smaller than the taper angle A of the base end side pin F2. As shown in FIG. 2, a spiral groove F31 is engraved on the outer peripheral surface of the tip end side pin F3. The spiral groove F31 may be clockwise or counterclockwise, but when the rotation tool F is rotated clockwise, it is preferable to engrave the spiral groove F31 counterclockwise from the base end side to the tip end side.

When rotating the rotation 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 fluid material is guided to the tip side by the spiral groove F31, so that the metal overflowing to the outside of the metal member 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 vertices F31c and F31c of the adjacent spiral grooves F31 is defined as the length X2. The height of the spiral side surface F31b is defined as the height Y2. The spiral angle D composed of the spiral bottom surface F31a and the spiral side surface F31b is formed at, for example, 45 to 90 °. The spiral groove F31 has a role of increasing frictional heat by coming into contact with the metal member to be joined and guiding the plastic fluid material to the tip side.

The design of the rotation tool F can be changed as appropriate. FIG. 3 is a side view showing a first modification of the rotation tool of the present invention. As shown in FIG. 3, in the rotation tool FA according to the first modification, the step angle C formed by the step bottom surface F21a of the pin step portion F21 and the step side surface F21b is 85 °. The step bottom surface F21a is parallel to the horizontal plane. As described above, the step bottom surface F21a is parallel to the horizontal plane, and the step angle C may be an acute angle within a range in which the plastic fluid material stays in the pin step portion F21 during friction stir welding and escapes to the outside without adhering. ..

FIG. 4 is a side view showing a second modification of the rotation tool of the present invention. As shown in FIG. 4, in the rotation tool FB according to the second modification, the step angle C of the pin step portion F21 is 115 °. The step bottom surface F21a is parallel to the horizontal plane. As described above, the step bottom surface F21a may be parallel to the horizontal plane, and the step angle C may be obtuse within the range in which the step bottom surface F21a functions as the pin step portion F21.

FIG. 5 is a side view showing a third modification of the rotation tool of the present invention. As shown in FIG. 5, in the rotation tool FC according to the third modification, the step bottom surface F21a is inclined 10 ° upward with respect to the horizontal plane from the rotation center axis of the tool toward the outer peripheral direction. The step side surface F21b is parallel to the vertical surface. As described above, the step bottom surface F21a may be formed so as to be inclined upward from the horizontal plane from the rotation center axis of the tool toward the outer peripheral direction within a range in which the plastic fluid material can be pressed during friction stir welding. The same effect as that of the following embodiment can be obtained by the first to third modifications of the rotation tool described above.

[First Embodiment]
The first embodiment of the present invention will be described with reference to the drawings as appropriate. In the friction stir welding method according to the present 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 collectively referred to as a metal member H to be joined. In the friction stir welding method according to the present embodiment, a preparation step, a butt step, a main joining step, and a tilting table removing step are performed.

The preparation step is a step of preparing the first metal member 1 and the second metal member 2 provided with the tilting table 50. 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 capable of friction stir welding, but in the present embodiment, it is formed mainly containing a first aluminum alloy. As the first aluminum alloy, for example, an aluminum alloy casting material such as JISH5302 ADC12 (Al—Si—Cu system) is used.

The large diameter portion 11 has a columnar shape. The small diameter portion 12 has a columnar shape and is formed concentrically on the tip 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. The step inclined surface 13a is provided on the end surface on the tip end side of the large diameter portion 11. The step side surface 13b is an outer peripheral surface of the small diameter portion 12. The step side surface 13b is formed so as to rise from the step inclined surface 13a toward the tip of the small diameter portion 12. The step inclined surface 13a is inclined from the inner peripheral portion in contact with the step side surface 13b to the outer peripheral portion in contact with the outer peripheral surface 11b of the large diameter portion 11 in a direction away from the step side surface 13b in the outward direction. As shown in FIG. 8, when viewed from a cross section passing through the central axis of the first metal member 1, the step inclined surface 13a has an inclination angle β with respect to a surface orthogonal to the central axis of the first metal member 1. Is tilted with. When the first metal member 1 and the second metal member 2 are abutted against each other, the step inclined surface 13a is inclined in a direction away from the second metal member 2 as it goes in the out-of-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 tip side pin F3. The step side surface 13b is perpendicular to the end surface 12a of the small diameter portion 12. That is, the step side surface 13b is parallel to the axial direction of the first metal member 1.

The second metal member 2 is a metal member having a cylindrical shape. The second metal member 2 has an inner diameter substantially equal to that of the small diameter portion 12, and has an outer diameter larger than the outer diameter of the large diameter portion 11. The second metal member 2 is preferably made of a wrought material. The metal is not particularly limited as long as it is a metal capable of friction stir welding, but in the present embodiment, it is formed mainly containing a second aluminum alloy. The second aluminum alloy is a material having a lower hardness than the first aluminum alloy. The second aluminum alloy is formed 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, but in the present embodiment, the outer diameter of the second metal member 2 is formed to be larger than the outer diameter of the first metal member 1. ing. Further, the inner diameter of the inner peripheral surface 21c of the second metal member 2 is the same as or substantially the same as the outer diameter of the small diameter portion 12 of the first metal member 1. In the present specification, the hardness refers to Brinell hardness, which can be measured by a method according to JIS Z 2243.

As shown in FIGS. 7 and 8, an inclined table 50 is formed at a position close to the boundary between the large diameter portion 11 and the small diameter portion 12 on the outer peripheral surface 11b of the large diameter portion 11 of the first metal member 1. There is. The inclined table 50 is composed of an inclined table side surface 50a, an inclined table side surface 50b, an inclined surface 50c, and a back surface 50d. The inclined table side surfaces 50a and 50b face each other and rise substantially vertically from the outer peripheral surface 11b. The inclined surface 50c has, for example, a rectangular shape in a plan view, and is inclined upward (in a direction away from the outer peripheral surface 11b) as the distance from the boundary between the large diameter portion 11 and the small diameter portion 12 increases. The inclined surface 50c is arranged parallel to the central axis of the first metal member 1. The back surface 50d rises vertically from the outer peripheral surface 11b and is perpendicular to the inclined table side surfaces 50a and 50b, respectively. It is preferable that the tilting table 50 is installed so as not to interfere with the rotating tool F when the butt portion J1 is friction-stir-welded in the main section of the main joining step described later. When the rotating tool F is raised along the inclined surface 50c and moved to the end position EP1 described later, the tilting table 50 does not leave a pull-out hole or a pull-out mark by the rotary tool F on the first metal member 1. It is preferable to have a thickness (height). That is, the inclined table 50 has a shape in which the thickness increases from the lower end to the upper end of the inclined surface 50c, but at least the tip side pin F3 has a portion thicker than the depth inserted into the inclined table 50. Is preferable.

The plan view shape of the inclined surface 50c can be various. Further, the tilting table 50 can be formed on the first metal member 1 by various means. For example, the first metal member 1 and the tilting table 50 may be integrally molded by a die casting method or the like, or the tilting table 50 may be retrofitted to the first metal member 1.

As shown in FIG. 8, the butt step is a step of butting the tip end portion of the first metal member 1 on the inclined table 50 side and the end portion of the second metal member 2. In the butt step, the small diameter portion 12 of the first metal member 1 is inserted into the opening 22 of the second metal member 2. As a result, the stepped inclined surface 13a of the first metal member 1 and the end surface 21a of the second metal member 2 are abutted to form the butt portion J1. A gap having a V-shaped cross section is formed in the butt portion J1 over the circumferential direction. Further, 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 the 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. The set movement route L1 is set closer to the second metal member 2 than the butt portion J1 and is parallel to the butt portion J1. The set movement route L1 is a movement route of the rotation tool F necessary for joining the butt portion J1 in the main joining step described later. The set movement route L1 will be described in detail later.

As shown in FIGS. 6, 10 and 11, this joining step is a step of friction stir welding of the butt portion J1 using the rotary tool F. In this joining step, the rotation tool F may be fixed and the metal member H to be joined may be rotated in the circumferential direction, or the metal member H to be joined may be fixed and the rotation tool F may be placed around the metal member H to be joined. You may move it.

As shown in FIG. 10, in the main joining step, the intrusion section from the start position SP1 set on the outer peripheral surface 21b of the second metal member 2 to the intermediate point S1 and the intrusion section from the intermediate point S1 on the set movement route L1 go around once. The three sections of the main section up to the intermediate point S2 and the detachment section from the intermediate point S2 to the end position EP1 located above the inclined surface 50c of the inclined table 50 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 away from the first metal member 1 with respect to the set movement route L1. In the present embodiment, the angle formed by the line segment connecting the start position SP1 and the intermediate point S1 and the set movement route L1 is set to an obtuse angle.

In the closet section of the main joining step, as shown in FIGS. 10 and 11, friction stir welding is performed from the start position SP1 to the intermediate point S1. In the closet section, the tip side pin F3 rotated clockwise is inserted into the start position SP1 while the rotation center axis Z is perpendicular to the outer peripheral surface 21b, and is moved to the intermediate point S1. That is, the rotation center axis Z is set to overlap the normal line of the outer peripheral surface 21b of the second metal member 2 while the rotation tool F moves relative to each other. 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" by at least reaching the intermediate point S1. That is, instead of keeping the rotation tool F in one place, the rotation tool F is gradually lowered while being moved to the set movement route L1. Here, the "predetermined depth" means the depth at which the tip end side pin F3 is pushed in in this section from the intermediate point S1 on the set movement route L1 to the intermediate point S2. In the present embodiment, the "predetermined depth" is set so that the flat surface F4, which is the tip of the tip side pin F3, reaches the step side surface 13b and penetrates the step side surface 13b.

Further, when the intermediate point S1 is reached, the outer peripheral surface of the base end side pin F2 is brought into contact with the outer peripheral surface 21b of the second metal member 2, and the outer peripheral surface of the tip end side pin F3 and the stepped inclined surface of the first metal member 1. Set so that it comes into slight contact with 13a. At this time, at least the first aluminum alloy on the first metal member 1 side is slightly scraped off by the contact between the tip side pin F3 and the first metal member 1, and the first aluminum alloy from the first metal member 1 side is plastically flowed. It is mixed into the second metal member 2 side as a material. Further, the flat surface F4 of the tip side pin F3 is set so as to penetrate the step side surface 13b.

The contact allowance (offset amount) N between the outer peripheral surface of the tip side pin F3 and the stepped inclined surface 13a of the first metal member 1 is set, for example, between 0 <N ≦ 1.0 mm, preferably 0 <N ≦. It is set between 0.85 mm, and more preferably between 0 <N ≦ 0.65 mm. As shown in FIG. 11, the set movement route L1 shows a locus through which the center of the flat surface F4 of the tip side pin F3 passes. That is, the set movement route L1 is set so that the stepped inclined surface 13a of the first metal member 1 and the outer peripheral surface of the tip side pin F3 are made parallel to each other and slightly contact each other in the circumferential direction of the butt portion J1. There is.

In this section, the rotation tool F is relatively moved so that the center of the flat surface F4 overlaps with 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 the second aluminum alloy of the second metal member 2 is allowed to flow into the gap of the butt portion J1. If the outer peripheral surface of the tip side pin F3 and the stepped inclined surface 13a are set so as not to come into contact with each other, the joint strength of the butt portion J1 becomes low. On the other hand, when the contact allowance N between the outer peripheral surface of the tip side pin F3 and the stepped 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. There is a risk of poor joining. Further, the tip end side pin F3 is brought into contact with the first metal member 1 and the second metal member 2, and the base end side pin F2 is moved relative to the second metal member 2.

In this section, as shown in FIGS. 6 and 11, when the rotation tool F goes around and the tip end side pin F3 reaches the intermediate point S2, the section shifts to the detachment section as it is.

FIG. 12 is a cross-sectional view showing a main joining step of the friction stir welding method according to the first embodiment. In the detachment section, the tip side pin F3 is gradually moved upward from the intermediate point S2 toward the end position EP1 (FIG. 12), and the tip side pin F3 is detached from the second metal member 2 at the end position EP1. (Fig. 6). That is, without keeping the rotation tool F in one place, the rotation tool F is gradually pulled out in the direction away from the first metal member 1 while moving to the end position EP1. A plasticized region W is formed in the movement locus of the rotation tool F.

The tilting table removing step is a step of removing the tilting table 50. In the tilting table removing step, for example, the tilting table 50 is completely removed with reference to the outer peripheral surface 11b by cutting or grinding.

According to the friction stir welding method in the present embodiment described above, the end position EP1 of the rotation tool F is set to the inclined table 50, and the inclined table 50 is cut off. This enables friction stir welding in which the first metal member 1 and the second metal member 2 do not have a pull-out hole or a pull-out mark. Further, as a result, no drawing holes and drawing marks remain on the outer peripheral surface 11b of the first metal member 1, so that a clean finish can be achieved.

Further, since the rotation tool F is raised along the inclined surface 50c of the inclined table 50, when the rotating tool F is moved to the end position EP1, the tip side pin F3 and the outer peripheral surface 11b can be separated from each other. As a result, the pull-out hole generated when the rotary tool F is detached does not remain on the outer peripheral surface 11b, but can be left only on the inclined table 50.
Further, the tilting table 50 can be easily formed by integrally molding the first metal member 1 of the present embodiment, for example, by die casting. Further, since it is sufficient to raise the tilting table 50 along the inclined surface 50c at a constant insertion depth, complicated work such as changing the rotation speed of the rotation tool F can be omitted.

Further, in this section of the main joining step, since the friction stir welding is performed in a state where the outer peripheral surface of the base end side pin F2 is in contact with the outer peripheral surface 21b of the second metal member 2, the generation of burrs can be suppressed. ..

Further, the frictional heat between the second metal member 2 and the tip side pin F3 stirs and plastically fluidizes the second aluminum alloy mainly on the second metal member 2 side of the butt portion J1, and the first metal member in the butt portion J1. The stepped inclined surface 13a of 1 and the end surface 21a of the second metal member 2 can be joined.

Further, in order to keep the outer peripheral surface of the tip side pin F3 slightly in contact with the stepped inclined surface 13a of the first metal member 1, the first aluminum alloy is mixed into the second metal member 2 as much as possible from the first metal member 1. Can be reduced. As a result, in the butt portion J1, the second aluminum alloy on the second metal member 2 side is mainly frictionally agitated, so that a decrease in joint strength can be suppressed. That is, in this joining step, the imbalance of the material resistance received by the tip side pin F3 on one side and the other side with respect to the rotation center axis Z of the tip side pin F3 can be minimized. As a result, the plastic fluid material is frictionally agitated in a well-balanced manner, so that a decrease in joint strength can be suppressed. Further, since the load applied to the rotation tool F can be reduced, the butt portion J1 can be joined without applying a large load to the rotation tool F.

Further, in this joining step, the position of the rotation tool F is set so that the outer peripheral surface of the tip side pin F3 and the stepped inclined surface 13a of the first metal member 1 are parallel to each other, so that the tip side pin F3 and the first The metal member 1 can be brought into contact with the metal member 1 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 the joint portion from becoming short of metal. Further, by setting the tip of the tip side pin F3 to reach the step side surface 13b of the first metal member 1, the butt portion J2 can also be reliably rubbed and agitated, so that the joint strength can be increased.

Here, when the tip side pin F3 is inserted into the set movement route L1, the start position of friction stir welding is set on the set movement route L1 and the tip side pin F3 is pushed in in the vertical direction until it reaches a predetermined depth. The frictional heat at the position becomes excessive. As a result, at the start position, the metal on the first metal member 1 side is likely to be mixed on the second metal member 2 side, which causes a problem of contributing to poor joining.
On the other hand, in the push-in section of the main joining step of the present embodiment, the tip side pin F3 is gradually pushed in while moving the rotation tool F from the start position SP1 to a position overlapping the set movement route L1 until it reaches a predetermined depth. By doing so, it is possible to prevent the rotation tool F from stopping on the set movement route L1 and causing the frictional heat to be locally excessive.

Similarly, in the detachment section of the main joining step, the set movement route L1 is separated by gradually pulling out the tip side pin F3 from a predetermined depth while moving the rotation tool F from the set movement route L1 to the end position EP1. It is possible to prevent the rotation tool F from stopping 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 excessive mixing of the first aluminum alloy from the first metal member 1 to the second metal member 2 resulting in poor joining.

Further, in this joining step, the positions of the start position SP1 and the end position EP1 may be appropriately set (the position of the end position EP1 can be appropriately set by selecting the installation position of the inclined table 50). By setting the angle between the start position SP1 and the set movement route L1 and the angle between the end position EP1 and the set movement route L1 to be obtuse, the movement speed of the rotation tool F decreases at the intermediate points S1 and S2. It is possible to smoothly shift to this section or the departure section without doing so. As a result, it is possible to prevent the frictional heat from becoming excessive due to the rotation tool F stopping or the moving speed decreasing on the set movement route L1. The rotation tool F may be moved from the start position SP1 to the set movement route L1 so that the locus of the rotation tool F draws an arc when viewed from above. Similarly, the rotation tool F may be moved from the set movement route L1 to the end position EP1 so that the locus of the rotation tool F draws an arc when viewed from above.

Further, in the present joining step, the rotation direction and the traveling direction of the rotation tool F may be appropriately set, but in the present embodiment, the first metal member 1 of the plasticized region W formed in the movement locus of the rotation tool F 1 The rotation direction and the traveling direction of the rotation tool F are set so that (butting portion J1 side) is on the shear side and the second metal member 2 side is on the flow side. By setting the first metal member 1 side to be the shear side, the stirring action by the tip side pin F3 around the butt portion J1 is enhanced, the temperature rise in the butt portion J1 can be expected, and the first metal in the butt portion J1. The stepped 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 speed of the outer circumference of the rotating tool with respect to the jointed portion is the value obtained by adding the magnitude of the moving speed to the magnitude of the tangential velocity on the outer circumference of the rotating tool. .. On the other hand, the flow side (Retreating side) refers to the side in which the relative speed of the rotating tool with respect to the jointed portion becomes low due to the rotation of the rotating tool in the direction opposite to the moving direction of the rotating tool.

Further, the first aluminum alloy of the first metal member 1 is a material having a higher hardness than the second aluminum alloy of the second metal member 2. As a result, the durability of the metal member to be joined, which is the joint between the first metal member 1 and the second metal member 2, can be enhanced. Further, it is preferable that the first aluminum alloy of the first metal member 1 is an aluminum alloy casting material and the second aluminum alloy of the second metal member 2 is an aluminum alloy wrought material. By using an Al—Si—Cu based aluminum alloy casting material such as JIS H5302 ADC12 as the first aluminum alloy, the castability, strength, machinability, etc. of the first metal member 1 can be improved. Further, by using, for example, JIS A1000 series or A6000 series as the second aluminum alloy, processability and thermal conductivity can be improved. Further, in the present embodiment, the first metal member 1 is made of a die-cast material and the second metal member 2 is made of a wrought material, so that the metal member H to be joined can be easily formed.

Further, in this joining step, since the entire circumference of the butt portion J1 is friction-stir welded, the airtightness and watertightness of the metal member H to be joined can be improved. Further, at the end portion of the main joining step, the rotation tool F is made to move toward the end position EP1 after completely passing through the intermediate point S1. That is, the airtightness and watertightness can be further improved by overlapping the ends of the plasticized region W formed by this joining step with each other.

In this joining step, the rotation speed of the rotation tool F may be constant, but may be variable. In the indentation section of the main joining step, if the rotation speed of the rotation tool F at the start position SP1 is V1 and the rotation speed of the rotation tool F in this section is V2, V1> V2 may be satisfied. The rotation speed V2 is a preset constant rotation speed in the set movement route L1. That is, at the start position SP1, the rotation speed may be set high, and the rotation speed may be gradually reduced in the closet section to shift to the main section.

Further, in the detachment section of the main joining step, if the rotation speed of the rotation tool F in this section is V2 and the rotation speed of the rotation tool F at the end position EP1 is V3, V3> V2 may be satisfied. That is, after shifting to the detachment section, the rotation tool F may be detached from the second metal member 2 while gradually increasing the rotation speed toward the end position EP1. When the rotary 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 indentation section or the detachment section is compensated by the rotation speed. Therefore, friction stir welding can be preferably performed.

[Second Embodiment]
Next, the friction stir welding method according to the second embodiment of the present invention will be described. In the second embodiment, as shown in FIG. 13, an inclined table is projected from the outer peripheral surface 21b at a position on the outer peripheral surface 21b of the second metal member 2 and close to the end surface 21a of the second metal member 2. 50 is provided. Therefore, the end position EP1 is also the inclined table 50 on the outer peripheral surface 21b of the second metal member 2, and the detachment section of this joining step is also on the outer peripheral surface 21b of the second metal member 2. In these respects, the second embodiment differs from the first embodiment. In the second embodiment, the parts different from the first embodiment will be mainly described.

The inclined table 50 is composed of an inclined table side surface 50a, an inclined table side surface 50b, an inclined surface 50c, and a back surface 50d. The inclined table side surfaces 50a and 50b face each other and rise substantially vertically from the outer peripheral surface 21b. The inclined surface 50c has, for example, a rectangular shape in a plan view, and is inclined upward (in a direction away from the outer peripheral surface 21b) as the distance from the end surface 21a increases. The inclined surface 50c is arranged parallel to the central axis of the second metal member 2. The back surface 50d rises vertically from the outer peripheral surface 21b and is perpendicular to the inclined table side surfaces 50a and 50b, respectively. It is preferable that the tilting table 50 is installed so as not to interfere with the rotating tool F when the butt portion J1 is friction-stir-welded in the main section of the main joining step described later.

In the production of the liquid-cooled jacket according to the second embodiment, a preparation step, a butt step, a main joining step, and a tilting table removing step are performed. The butt step and the tilting table removing step are the same as those in the first embodiment. In the preparatory step, the inclined table 50 is formed on the outer peripheral surface 21b of the second metal member 2. In this joining step, friction stir welding is performed in the closet section and this section in the same manner as in the first embodiment, and when the rotary tool F reaches the intermediate point S2, the section shifts to the leaving section as it is. In the detachment section, the rotation tool F is moved to the inclined table 50 arranged on the second metal member 2, and the tip side pin F3 is gradually moved upward from the intermediate point S2 to the end position EP1. At the end position EP1, the tip side pin F3 is separated from the second metal member 2. That is, without keeping the rotation tool F in one place, the rotation tool F is gradually pulled out in the direction away from the second metal member 2 while moving to the end position EP1.

The friction stir welding method of the present embodiment described above can also obtain substantially the same effect as that of the first embodiment. Further, the tilting table 50 may be arranged on the second metal member 2 as in the present embodiment.

Further, when the inclined table 50 is formed of the second aluminum alloy like the second metal member 2, the second aluminum alloy has a relatively low hardness, so that the operation of the inclined table removing step becomes easy.

[Modification example]
A modified example of the above embodiment will be described. FIG. 14 is a perspective view showing a preparatory step of the friction stir welding method according to the first modification. This modification is different from the first embodiment in that the inclined surface 50c of the inclined table 50 is formed in an arc shape in a top view.

As a result, the tip side pin F3 can be relatively moved in an arc shape when the detachment section of the main joining step is frictionally agitated, so that the rotation tool F can be smoothly moved from this section to the detachment section. The tilting table 50 in this case may be formed on the outer peripheral surface 11b of the first metal member 1.

FIG. 15 is a perspective view showing friction stir in the closet section in the main joining step of the friction stir welding method according to the second modification. In this joining step, as shown in FIG. 15, the start position SP1 is set on the set movement route L1 and the closet section is set from the start position SP1 to the intermediate point S1. In the closet section of the second modification, it is possible to prevent the frictional heat from becoming excessive at one point of the set movement route L1 while moving the rotation tool F on the set movement route L1. This section and the withdrawal section are the same as those in the above embodiment.

1 1st metal member 2 2nd metal member 11 Large diameter part 11b Outer peripheral surface 12 Small diameter part 13a Step inclined surface 13b Step side surface 21a End surface 21b Outer peripheral surface 21c Inner peripheral surface 22 Opening 50 Inclined table L1 Setting movement route F Rotation tool F1 Base shaft part F2 Base end side pin F3 Tip side pin F4 Flat surface J1 Butt part SP1 Start position EP1 End position W Plasticization area

Claims (4)

A columnar first metal member having a small diameter portion at the end of a large diameter portion and a tubular second metal member having an inner diameter substantially equal to that of the small diameter portion are abutted against each other to be joined. This is a friction stir welding method in which friction stir welding is performed on the butt portion of a metal member.
The first metal member is formed of a first aluminum alloy, the second metal member is formed of a second aluminum alloy, and the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy. And
The rotary tool used for friction stir welding has a base end side pin and a tip end side pin.
The taper angle of the base end side pin is larger than the taper angle of the tip end side pin, and a stepped pin step portion is formed on the outer peripheral surface of the base end side pin, and the tip end side pin is formed. The outer peripheral surface of the is inclined so as to be tapered,
A preparatory step of forming an inclined table that is close to the boundary between the large-diameter portion and the small-diameter portion of the first metal member and protrudes from the outer peripheral surface of the first metal member.
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 first (Ii) A butt step of abutting the end face of the metal member and the stepped inclined surface of the first metal member to form a gap having a V-shaped cross section in the butt portion.
The tip end side pin of the rotating tool is inserted into the outer peripheral surface of the second metal member, and the outer peripheral surface of the base end side pin is brought into contact with the outer peripheral surface of the second metal member while the outer peripheral surface of the tip end side pin is brought into contact with the outer peripheral surface. A setting set on the second metal member side with respect to the abutting portion while allowing the second aluminum alloy to flow into the gap in a state where the surface is slightly in contact with the stepped inclined surface of the first metal member. After rubbing and stirring the abutting portion around the outer peripheral surface of the second metal member at a predetermined depth along the movement route, the tip side pin rises along the inclined surface of the inclined table. The main joining process of moving and pulling out on the upper side of the inclined surface,
A friction stir welding method comprising a tilting table removing step of removing the tilting table. A columnar first metal member having a small diameter portion at the end of a large diameter portion and a tubular second metal member having an inner diameter substantially equal to that of the small diameter portion are abutted against each other to be joined. This is a friction stir welding method in which friction stir welding is performed on the butt portion of a metal member.
The first metal member is formed of a first aluminum alloy, the second metal member is formed of a second aluminum alloy, and the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy. And
The rotary tool used for friction stir welding has a base end side pin and a tip end side pin.
The taper angle of the base end side pin is larger than the taper angle of the tip end side pin, and a stepped pin step portion is formed on the outer peripheral surface of the base end side pin, and the tip end side pin is formed. The outer peripheral surface of the is inclined so as to be tapered,
A preparatory step of forming an inclined table that is close to the end surface of the second metal member and protrudes from the outer peripheral surface of the second metal member.
By inserting the small diameter portion of the first metal member into the opening on the inclined table side 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. A butt step of abutting the end face of the second metal member and the stepped inclined surface of the first metal member to form a gap having a V-shaped cross section in the butt portion.
The tip end side pin of the rotating tool is inserted into the outer peripheral surface of the second metal member, and the outer peripheral surface of the base end side pin is brought into contact with the outer peripheral surface of the second metal member while the outer peripheral surface of the tip end side pin is brought into contact with the outer peripheral surface. A setting set on the second metal member side with respect to the abutting portion while allowing the second aluminum alloy to flow into the gap in a state where the surface is slightly in contact with the stepped inclined surface of the first metal member. After rubbing and stirring the abutting portion around the outer peripheral surface of the second metal member at a predetermined depth along the movement route, the tip side pin rises along the inclined surface of the inclined table. The main joining process of moving and pulling out on the upper side of the inclined surface,
A friction stir welding method comprising a tilting table removing step of removing the tilting table. 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 abutted against each other to be joined. This is a friction stir welding method in which friction stir welding is performed on the butt portion of a metal member.
The first metal member is formed of a first aluminum alloy, the second metal member is formed of a second aluminum alloy, and the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy. And
The rotary tool used for friction stir welding has a base end side pin and a tip end side pin.
The taper angle of the base end side pin is larger than the taper angle of the tip end side pin, and a stepped pin step portion is formed on the outer peripheral surface of the base end side pin, and the tip end side pin is formed. The outer peripheral surface of the is inclined so as to be tapered,
A preparatory step of forming an inclined table that is close to the boundary between the large-diameter portion and the small-diameter portion of the first metal member and protrudes from the outer peripheral surface of the first metal member.
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 first (Ii) A butt step of abutting the end face of the metal member and the stepped inclined surface of the first metal member to form a gap having a V-shaped cross section in the butt portion.
The tip end side pin of the rotating tool is inserted into the outer peripheral surface of the second metal member, and the outer peripheral surface of the base end side pin is brought into contact with the outer peripheral surface of the second metal member while the outer peripheral surface of the tip end side pin is brought into contact with the outer peripheral surface. A setting set on the second metal member side with respect to the abutting portion while allowing the second aluminum alloy to flow into the gap in a state where the surface is slightly in contact with the stepped inclined surface of the first metal member. After rubbing and stirring the abutting portion around the outer peripheral surface of the second metal member at a predetermined depth along the movement route, the tip side pin rises along the inclined surface of the inclined table. The main joining process of moving and pulling out on the upper side of the inclined surface,
A friction stir welding method comprising a tilting table removing step of removing the tilting table. 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 abutted against each other to be joined. This is a friction stir welding method in which friction stir welding is performed on the butt portion of a metal member.
The first metal member is formed of a first aluminum alloy, the second metal member is formed of a second aluminum alloy, and the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy. And
The rotary tool used for friction stir welding has a base end side pin and a tip end side pin.
The taper angle of the base end side pin is larger than the taper angle of the tip end side pin, and a stepped pin step portion is formed on the outer peripheral surface of the base end side pin, and the tip end side pin is formed. The outer peripheral surface of the is inclined so as to be tapered,
A preparatory step of forming an inclined table that is close to the end surface of the second metal member and protrudes from the outer peripheral surface of the second metal member.
By inserting the small diameter portion of the first metal member into the opening on the inclined table side 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. A butt step of abutting the end face of the second metal member and the stepped inclined surface of the first metal member to form a gap having a V-shaped cross section in the butt portion.
The tip end side pin of the rotating tool is inserted into the outer peripheral surface of the second metal member, and the outer peripheral surface of the base end side pin is brought into contact with the outer peripheral surface of the second metal member while the outer peripheral surface of the tip end side pin is brought into contact with the outer peripheral surface. A setting set on the second metal member side with respect to the abutting portion while allowing the second aluminum alloy to flow into the gap in a state where the surface is slightly in contact with the stepped inclined surface of the first metal member. After rubbing and stirring the abutting portion around the outer peripheral surface of the second metal member at a predetermined depth along the movement route, the tip side pin rises along the inclined surface of the inclined table. The main joining process of moving and pulling out on the upper side of the inclined surface,
A friction stir welding method comprising a tilting table removing step of removing the tilting table.

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