JP6756253B2 - Joining method - Google Patents

Description

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

For example, Patent Document 1 discloses a joining method for joining a first metal member and a second metal member by friction stir welding. In the joining method, after the first metal member and the second metal member are butted to form a butt portion, only the stirring pin of the rotary tool is brought into contact with the first metal member and the second metal member to form the butt portion. On the other hand, friction stir welding is performed.

Japanese Unexamined Patent Publication No. 2013-39613

In the conventional joining method, since the plastically fluidized metal is not pressed by the shoulder portion of the rotating tool, there is a problem that the plastically fluidized metal overflows to the outside and the joint portion becomes short of metal.
Further, in the conventional joining method, when the temperature of the plastically fluidized metal decreases, the metal at the joint portion shrinks, so that the joined metal members may not be flat and may be distorted. Has the problem that the quality of the product deteriorates.
Further, there is a possibility that a gap may be formed in the portion of the joint portion opposite to the plasticized region due to the shrinkage of the metal in the joint portion. As described above, when a welding defect (Kissing Bond) is formed in the joint portion, there is a problem that the tensile strength of the joint portion is lowered and the watertightness and airtightness of the joint portion are lowered.

Therefore, the present invention solves the above-mentioned problems, prevents metal shortage of the joint, and applies thermal strain to the joint in advance before the friction stir welding step to improve the quality of the joint. The challenge is to provide.

The first invention for solving the above-mentioned problems is a joining method for joining a first metal member and a second metal member, in which the first metal member and the second metal member are butted against each other to form a butt portion. The butt step of forming, the welding step of welding from the front surface side to the butt portion, and the back surface of the first metal member or the second metal member by turning over the first metal member and the second metal member. The arrangement step of arranging the auxiliary member so as to be in surface contact with the metal member, and the stirring pin of the rotating tool is inserted from the surface side of the auxiliary member while rotating, and only the stirring pin is inserted into the first metal member and the second metal member. And the friction stirring step of joining the first metal member, the second metal member and the auxiliary member by relatively moving the rotating tool along the abutting portion in contact with the auxiliary member, and burrs are formed. It is characterized by including a removing step of removing the auxiliary member from the first metal member or the second metal member.

A second invention for solving the above problems is a joining method for joining a first metal member and a second metal member, in which the first metal member and the second metal member are butted against each other to form a butt portion. The butt step to be formed, the welding step of welding to the butt portion from the front surface side, and the back surface of the first metal member and the second metal member by turning over the first metal member and the second metal member. The arrangement step of arranging the auxiliary member so as to make surface contact with both of the above, and inserting from the surface side of the auxiliary member while rotating the stirring pin of the rotating tool, and only the stirring pin is the first metal member and the second. A friction stirring step of joining the first metal member, the second metal member and the auxiliary member by relatively moving the rotating tool along the abutting portion in contact with the metal member and the auxiliary member, and a burr. said auxiliary member and a removing step of removing from said first metal member and the second metallic member, only containing, in the disposing step, the auxiliary member the first metal member and the second metal member but formed While arranging the metal in one of the above parts, the metal is arranged so as to slightly project to the other side with the butt portion sandwiched therein. In the friction stirring step, burrs generated in the friction stirring joint are the first of the auxiliary members. It is characterized in that the joining condition is set so that it is formed on either one side of the metal member and the second metal member .
A third invention for solving the above problems is a joining method for joining a first metal member and a second metal member, in which the first metal member and the second metal member are butted against each other to form a butt portion. The butt step to be formed, the welding step of welding to the butt portion from the front surface side, and the back surface of the first metal member and the second metal member by turning over the first metal member and the second metal member. The arrangement step of arranging the auxiliary member so as to make surface contact with both of the above, and inserting from the surface side of the auxiliary member while rotating the stirring pin of the rotating tool, and only the stirring pin is the first metal member and the second. A friction stirring step of joining the first metal member, the second metal member and the auxiliary member by relatively moving the rotating tool along the abutting portion in contact with the metal member and the auxiliary member, and a burr. The welding metal formed in the butt portion in the welding step and the welding metal formed in the butt portion and the friction stirring step include a removing step of removing the auxiliary member formed of the first metal member and the second metal member. It is characterized in that it is in contact with the plasticized region formed in the butt portion.

According to the joining method in the first to third inventions, the first metal member and the second metal member are joined, and in addition to the first metal member and the second metal member, the auxiliary member is also frictionally stirred at the same time. By joining, it is possible to prevent a metal shortage at the joint.
Further, by performing the welding step from the front surface side to the butt portion and then performing the friction stir step from the back surface side to the butt portion, thermal strain is applied to the joint portion in advance by the welding process before the friction stirring process. As a result, it is possible to prevent the joined metal members from bending after the friction stir step and to form a joint portion having excellent watertightness and airtightness.
Further, since the burr can be removed together with the auxiliary member in the removing step, the work of removing the burr becomes easy.

Further, in the friction stir welding step, it is preferable to set the joining conditions so that burrs generated in the friction stir welding are formed on the auxiliary member. According to such a joining method, the work of removing burrs can be performed more easily.

Further, in the arrangement step, the auxiliary member is arranged on one of the first metal member and the second metal member, and is arranged so as to slightly project to the other side with the butt portion sandwiched therein. In the friction stir welding step, it is preferable to set the joining conditions so that the burrs generated in the friction stir welding are formed on either one of the first metal member and the second metal member of the auxiliary members.

According to such a joining method, the work of removing burrs can be performed more easily. In addition, the metal shortage of the joint can be further prevented by slightly projecting the auxiliary member to the other side with the butt portion sandwiched between them.

Further, it is preferable that the weld metal formed in the butt portion in the welding step is brought into contact with the plasticized region formed in the butt portion in the friction stir welding step. According to such a joining method, the watertightness and airtightness of the joined portion can be further improved.

According to the joining method according to the present invention, it is possible to prevent a metal shortage in the joint, and further, by applying thermal strain to the joint in advance before the friction stir welding step, the quality of the joint is improved and the watertightness is improved. And it is possible to form a joint having excellent airtightness.

It is sectional drawing which shows the butt process and welding process of 1st Embodiment of this invention. It is sectional drawing which shows after the welding process which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the arrangement process which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the friction stir welding process which concerns on 1st Embodiment of this invention. It is sectional drawing which shows after the friction stir welding step which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the removal process which concerns on 1st Embodiment of this invention. It is sectional drawing which shows after the removal process which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the welding process and arrangement process which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the friction stir welding process which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the removal process which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows after the removal process which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the welding process and arrangement process which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the friction stir welding process which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the removal process which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows after the removal process which concerns on 3rd Embodiment of this invention.

[First Embodiment]
The joining method according to the first embodiment of the present invention will be described in detail with reference to the drawings. In the joining method according to the present embodiment, a butt step, a welding step, a placement step, a friction stir step, and a removal step are performed. In the following description, the "front surface" means the surface opposite to the "back surface".

As shown in FIG. 1, the butt step is a step of butt-butting the first metal member 1 and the second metal member 2. The first metal member 1 and the second metal member 2 are metal plate-shaped members. The materials of the first metal member 1 and the second metal member 2 are not particularly limited as long as they are metals that can be agitated by friction. For example, aluminum, aluminum alloy, copper, copper alloy, titanium, titanium alloy, magnesium, magnesium alloy and the like. It may be selected appropriately from.
The plate thicknesses of the first metal member 1 and the second metal member 2 are the same. The plate thicknesses of the first metal member 1 and the second metal member 2 may be appropriately set.

In the butt step, the end face 1a of the first metal member 1 and the end face 2a of the second metal member 2 are butted to form the butt portion J1. The surface 1b of the first metal member 1 and the surface 2b of the second metal member 2 are flush with each other.

Further, the first metal member 1 and the second metal member 2 are placed on the upper surface of the gantry T of the first metal member 1 and the second metal member 2 so that the surfaces 1b and 2b are on the upper side. The member 1 and the second metal member 2 are immovably restrained on the gantry T by using a jig (not shown).

The welding step is a step of welding the butt portion J1 between the first metal member 1 and the second metal member 2 from the surface side. In the welding process, the type of welding is not particularly limited, and for example, arc welding such as MIG welding and TIG welding or laser welding can be performed.
In the welding step, the welding torch is brought close to the surface side of the butt portion J1 and the welding torch is relatively moved along the butt portion J1 to weld the surface side of the butt portion J1.
As a result, the weld metal W2 is formed on the surface side of the butt portion J1. The weld metal W2 is formed inside the butt portion J1 and is built up on the surface of the butt portion J1.

After the welding process, the first metal member 1 and the second metal member 2 are turned upside down and placed on the upper surface of the gantry T, and the first metal member 1 and the second metal member 2 are placed on a jig (not shown). It is used to immobilize the gantry T. By turning the first metal member 1 and the second metal member 2 upside down in this way, the back surfaces 1c and 2c of the first metal member 1 and the second metal member 2 are arranged on the upper side.
A linear concave groove T1 is formed in the gantry T of the first embodiment. In the welding step, the first metal member 1 and the second metal member 2 are arranged with respect to the gantry T so that the front side of the butt portion J1 is arranged directly above the concave groove T1.

As shown in FIG. 2, when the temperature of the joint portion drops after the welding step, the weld metal W2 contracts. Therefore, the weld metal W2 is attached to the joint portion of the first metal member 1 and the second metal member 2. Distortion occurs so that the shape becomes convex toward the opposite side (back surface 1c, 2c side). That is, the joint portion between the first metal member 1 and the second metal member 2 is distorted so that the weld metal W2 side is recessed. In this way, thermal strain is applied to the joint portion by the welding process.

The arranging step is a step of arranging the auxiliary member 10 on the first metal member 1 or the second metal member 2. The auxiliary member 10 is a metal plate-shaped member. The auxiliary member 10 is not particularly limited as long as it is a metal capable of friction stir welding, but in the present embodiment, it is made of the same material as the first metal member 1 and the second metal member 2.
The plate thickness of the auxiliary member 10 is appropriately set so that the plasticized region W1 (see FIG. 7) after the friction stir welding step described later does not run out of metal. In the present embodiment, the plate thickness of the auxiliary member 10 is set to be thinner than that of the first metal member 1. Although the auxiliary member 10 has a plate shape in the present embodiment, it may have another shape.

In the arranging step, the back surface 10c of the auxiliary member 10 and the back surface 2c of the second metal member 2 are brought into surface contact with each other. The auxiliary member 10 is arranged so as to be in surface contact with only the second metal member 2 (or the first metal member 1). In the present embodiment, the end face 10a of the auxiliary member 10 and the end face 2a of the second metal member 2 are arranged so as to be flush with each other.

Further, the first metal member 1, the second metal member 2, and the auxiliary member 10 are immovably restrained on the gantry T by using a jig (not shown). At this time, since the first metal member 1 and the second metal member 2 are pressed against the upper surface of the gantry T by the jig, the first metal member 1 and the second metal member 2 are fixed flatly on the upper surface of the gantry T. To.

Further, a linear concave groove T1 is formed in the gantry T of the first embodiment. In the arranging step, the first metal member 1 and the second metal member 2 are arranged with respect to the gantry T so that the front side of the butt portion J1 is arranged directly above the concave groove T1. As a result, the build-up portion of the weld metal W2 formed on the front side of the butt portion J1 enters the recessed groove T1, so that the build-up portion of the weld metal W2 can be prevented from hitting the upper surface of the gantry T. Therefore, the first metal member 1 and the second metal member 2 can be arranged flat on the upper surface of the gantry T.
In addition, without providing the concave groove T1 in the gantry T, a plurality of plate members are arranged on the upper surface of the gantry T at intervals, and the first metal member 1 and the second metal member 2 are placed between the plate members. May be good. In this configuration, the weld metal W2 can be arranged between the plate materials, and the built-up portion of the weld metal W2 can be inserted between the plate materials.
Further, the built-up portion of the weld metal W2 may be cut off after the welding step. In this configuration, it is not necessary to form the concave groove T1 on the upper surface of the gantry T.

As shown in FIG. 4, the friction stir welding step is a step of joining the butt portion J1 between the first metal member 1 and the second metal member 2 by friction stir welding from the back surface side using the joining rotary tool F. The joining rotary tool F is composed of a connecting portion F1 and a stirring pin F2. The rotary tool F for joining corresponds to the "rotation tool" in the claims. The rotary tool F for joining is made of, for example, tool steel. The connecting portion F1 is a portion connected to a rotating shaft (not shown) of the friction stir welding device. The connecting portion F1 has a columnar shape.

The stirring pin F2 hangs down from the connecting portion F1 and is coaxial with the connecting portion F1. The stirring pin F2 is tapered as it is separated from the connecting portion F1. A spiral groove is engraved on the outer peripheral surface of the stirring pin F2. In the present embodiment, in order to rotate the joining rotation tool F counterclockwise, the spiral groove is formed clockwise from the base end to the tip end. In other words, the spiral groove is formed clockwise when viewed from above when the spiral groove is traced from the base end to the tip end.

When the joint rotation tool F is rotated clockwise, it is preferable to form the spiral groove counterclockwise from the base end to the tip end. In other words, the spiral groove in this case is formed counterclockwise when viewed from above when the spiral groove is traced from the base end to the tip end. By setting the spiral groove in this way, the metal plastically fluidized during friction stir welding is guided to the tip end side of the stirring pin F2 by the spiral groove. As a result, the amount of metal that overflows to the outside of the metal member to be joined (first metal member 1, second metal member 2 and auxiliary member 10) can be reduced. The spiral groove may be omitted.

The joining rotation tool F may be attached to a friction stir device such as a machining center, or may be attached to, for example, an arm robot having a rotating means such as a spindle unit at the tip.

In the friction stir welding step, only the stirring pin F2 rotated counterclockwise is inserted from the surface 10b of the auxiliary member 10 into the abutting portion J1, and the metal member to be joined and the connecting portion F1 are relatively moved while being separated from each other. In other words, friction stir welding is performed with the base end portion of the stirring pin F2 exposed.
Then, in a state where the first metal member 1, the second metal member 2, and the auxiliary member 10 are in contact with the stirring pin F2, a rotary tool for joining is formed from the front side to the back side of FIG. 4 along the butt portion J1. Move F relative to each other. In the present embodiment, the traveling direction of the joining rotation tool F is set so that the auxiliary member 10 is located on the left side of the traveling direction of the joining rotation tool F.

The rotation direction and the traveling direction of the joining rotation tool F are not limited to those described above, and may be appropriately set. For example, the joining rotation tool F may be rotated clockwise while the auxiliary member 10 is arranged on the left side in the traveling direction of the joining rotation tool F. Alternatively, the joining rotation tool F may be rotated to the left or right while the auxiliary member 10 is arranged on the right side in the traveling direction of the joining rotation tool F. Conditions such as the rotation direction of the joining rotation tool F and the preferable positional relationship of the auxiliary member 10 will be described later.

The insertion depth of the stirring pin F2 may be appropriately set according to the plate thickness of the first metal member 1 and the second metal member 2 while keeping the stirring pin F2 and the butt portion J1 in contact with each other. As a result, the butt portion J1 is friction stir welded. A plasticized region W1 is formed in the movement locus of the joining rotation tool F. After the friction stir welding step, a burr V is formed at the end of the auxiliary member 10 as shown in FIG.

As shown in FIG. 6, the removing step is a step of removing the auxiliary member 10 from the second metal member 2. In the removing step, for example, the auxiliary member 10 is manually bent in a direction away from the second metal member 2 and removed from the second metal member 2. As a result, as shown in FIG. 7, the first metal member 1 and the second metal member 2 are joined.

When the temperature of the joint portion drops after the friction stir welding step, the metal in the plasticized region W1 shrinks. Therefore, the joint portion between the first metal member 1 and the second metal member 2 is opposite to the plasticized region W1 side. Distortion occurs so that the shape becomes convex toward the side. That is, the joint portion between the first metal member 1 and the second metal member 2 is distorted so that the plasticized region W1 side is recessed.
In the joining method of the first embodiment, before the friction stir welding step, thermal strain is applied to the joint portion by the welding step so as to have a convex shape toward the opposite side (back surface 1c, 2c side) of the weld metal W2. There is. Therefore, the first metal member 1 and the second metal member 2 become flat due to the distortion of the joint portion in the friction stir welding step.

Further, when the temperature of the joint portion is lowered and the metal in the plasticized region W1 shrinks, a gap is formed in the joint portion on the opposite side (back surface side) of the plasticized region W1 and a welding defect (welding defect) is formed in the joint portion. Kissing Bond) may be formed. However, in the joining method of the first embodiment, since the back surface side of the joint portion is welded before the friction stir welding step, it is possible to prevent welding defects from occurring in the joint portion.

Further, in the friction stir welding step of the first embodiment, the weld metal W2 formed on the front surface side of the butt portion J1 in the welding step and the plasticized region W1 formed on the back surface side of the butt portion J1 in the friction stir welding step are formed. The insertion depth of the stirring pin F2 is set so as to make contact.

According to the joining method according to the first embodiment described above, as shown in FIG. 5, the first metal member 1 and the second metal member 2 are joined, and the first metal member 1 and the second metal member are joined. In addition to 2, the auxiliary member 10 is also friction-stir-welded at the same time to prevent a metal shortage in the joint portion (plasticized region W1). Further, according to the first embodiment, it is possible to prevent the metal shortage by arranging the auxiliary member 10 only on one side instead of both the first metal member 1 and the second metal member 2.

Further, in the first embodiment, as shown in FIG. 1, a welding step is performed on the butt portion J1 from the front surface side, and then a friction stir welding step is performed on the butt portion J1 from the back surface side as shown in FIG. Prior to the friction stir welding process, thermal strain is applied to the joint portion in advance by a welding process. As a result, it is possible to prevent the joined first metal member 1 and the second metal member 2 from bending after the friction stir step, and to form a joint portion having excellent watertightness and airtightness. Further, the joint strength of the first metal member 1 and the second metal member 2 can be increased.

Further, in the first embodiment, as shown in FIG. 6, the burr V is formed on the auxiliary member 10 by the friction stir welding step, but the auxiliary member 10 can be removed together with the auxiliary member 10 in the removing step. Thereby, the work of removing the burr can be easily performed. As shown in FIG. 5, after the friction stir welding step, the end face of the auxiliary member 10 is inclined so that the plate thickness becomes thinner toward the butt portion J1. A removing device or the like may be used for the auxiliary member 10, but in the present embodiment, the auxiliary member 10 can be easily removed manually.

Here, in the joining method according to the first embodiment, since the auxiliary member 10 is set thinner than the first metal member 1 and the second metal member 2, the shoulder portion is pressed into the metal member and rubbed as in the conventional case. When stirring is performed, the auxiliary member 10 is blown to the outside due to the contact between the shoulder portion and the auxiliary member 10, and the metal shortage at the joint portion cannot be compensated. However, in the first embodiment, since only the stirring pin F2 of the rotary tool F for joining is brought into contact with the first metal member 1, the second metal member 2 and the auxiliary member 10 for frictional stirring, the auxiliary member 10 is externally provided. It is possible to make up for the metal shortage at the joint without being blown away. In addition, the load acting on the friction stir welding device can be reduced as compared with the case where the shoulder portion is brought into contact with the friction stir.

In the first embodiment, as shown in FIG. 4, the shear side (advancing side: the side where the moving speed of the rotating tool is added to the tangential speed on the outer circumference of the rotating tool) is the other side (joining center). The moving direction and the rotating direction of the joining rotation tool F are set so as to be on the right side of the line X). The rotation direction and the traveling direction of the joining rotation tool F are not limited to those described above, and may be appropriately set.

For example, when the rotation speed of the joining rotation tool F is slow, the shear flow is on the shear side compared to the flow side (retreating side: the side where the movement speed of the rotation tool is subtracted from the tangential speed on the outer circumference of the rotation tool). Since the temperature of the material tends to rise, a large amount of burr V tends to occur on the shear side outside the plasticized region W1.
On the other hand, for example, when the rotation speed of the joining rotation tool F is high, the temperature of the plastic fluid material rises on the shear side, but there are many burrs V on the flow side outside the plasticization region W1 due to the high rotation speed. It tends to occur.

In the first embodiment, since the rotation speed of the joining rotation tool F is set to be high, as shown in FIG. 5, a large number of burrs V tend to occur on the flow side outside the plasticization region W1. That is, the burr V can be concentrated on the auxiliary member 10 side. Further, by setting the rotation speed of the joining rotation tool F to be high, the moving speed (feeding speed) of the joining rotation tool F can be increased. As a result, the joining cycle can be shortened.

As shown in FIG. 4, in the friction stir step, which side of the joining rotation tool F in the traveling direction the burr V is generated depends on the joining conditions. The joining conditions include the rotation speed, rotation direction, movement speed (feed speed) of the joining rotation tool F, the inclination angle (taper angle) of the stirring pin F2, the first metal member 1, the second metal member 2, and the auxiliary member. It is determined by each element such as the material of 10 and the thickness of the auxiliary member 10 and the combination of these elements. Depending on the joining conditions, the side where the burr V is generated or the side where the burr V is generated a lot is in surface contact with the first metal member 1 and the second metal member 2 with respect to the joining center line X. If it is set to be on the side, the work of removing burrs can be easily performed, which is preferable.

[Second Embodiment]
Next, the joining method according to the second embodiment will be described. As shown in FIG. 8, the joining method according to the second embodiment is different from the first embodiment in that the auxiliary member 10 is arranged so as to come into contact with both the first metal member 1 and the second metal member 2. .. Further, the rotation direction of the joining rotation tool F is also different from that of the first embodiment. In the joining method according to the second embodiment, the parts different from the first embodiment will be mainly described.

The joining method according to the second embodiment includes a butt step, a welding step, a placement step, a friction stir step, and a removal step. Since the butt step and the welding step of the second embodiment are the same as those of the first embodiment, the description thereof will be omitted.

After welding the butt portion J1 from the surface side in the welding step, the first metal member 1 and the second metal member 2 are turned upside down and restrained on the upper surface of the gantry T. When the temperature of the joint portion drops after the welding step, the joint portion is distorted so as to have a convex shape toward the opposite side (back surface 1c, 2c side) of the weld metal W2. In this way, thermal strain is applied to the joint portion by the welding process.

As shown in FIG. 8, the arrangement step of the second embodiment is a step of bringing the back surface 1c of the first metal member 1 and the back surface 2c of the second metal member 2 into surface contact with the back surface 10c of the auxiliary member 10. The plate thickness of the auxiliary member 10 is appropriately set so that the plasticized region W1 after the friction stir welding step described later does not run out of metal.
In the arrangement step of the second embodiment, the auxiliary member 10 is arranged so that the center is substantially located at the butt portion J1.

As shown in FIG. 9, the friction stir welding step is a step of joining the butt portion J1 between the first metal member 1 and the second metal member 2 by friction stir welding using the joining rotary tool F.
In the second embodiment, in order to rotate the joining rotation tool F clockwise, the spiral groove of the stirring pin F2 is formed counterclockwise from the base end to the tip end.

In the friction stir step of the second embodiment, the stirring pin F2 rotated clockwise is inserted from the surface 10b of the auxiliary member 10, and the insertion depth of the stirring pin F2 is set so as to reach the butt portion J1.
In the friction stir welding step of the second embodiment, only the stirring pin F2 rotated clockwise is inserted into the butt portion J1 and the metal member to be joined and the connecting portion F1 are moved while being separated from each other. In other words, friction stir welding is performed with the base end portion of the stirring pin F2 exposed.
Then, with the first metal member 1, the second metal member 2, and the auxiliary member 10 in contact with the stirring pin F2, the joining rotation tool F is moved from the front side to the back side in FIG. 9 along the butt portion J1. Move relative to each other. As a result, the butt portion J1 is friction stir welded. A plasticized region W1 is formed in the movement locus of the joining rotation tool F.
In the second embodiment, since the joining rotation tool F is rotated at high speed, burrs V tend to be generated more on the flow side than on the shear side.

As shown in FIG. 10, the removing step is a step of removing the auxiliary member 10 separated by the friction stir welding step from the first metal member 1 and the second metal member 2. In the removing step, the auxiliary members 10 and 10 are bent and removed in the directions away from the first metal member 1 and the second metal member 2, respectively.

Although the joint portion is distorted after the friction stir welding step, the first metal member 1 is as shown in FIG. 11 because the joint portion is preliminarily subjected to thermal strain by the welding step before the friction stir welding step. And the second metal member 2 become flat. Further, in the friction stir welding step, since the back surface side of the butt portion J1 is welded before the front surface side of the butt portion J1 is frictionally agitated, it is possible to prevent welding defects from occurring in the joint portion.

According to the joining method according to the second embodiment described above, as shown in FIG. 10, the first metal member 1 and the second metal member 2 are joined, and the first metal member 1 and the second metal member are joined. In addition to 2, the auxiliary member 10 is also friction-stir-welded at the same time to prevent a metal shortage in the joint portion (plasticized region W1). Further, since the auxiliary member 10 is arranged so as to straddle both the first metal member 1 and the second metal member 2, it is possible to more reliably prevent the metal shortage at the joint and to replenish the metal in a well-balanced manner. it can.

Further, in the second embodiment, as shown in FIG. 8, a welding step is performed on the butt portion J1 from the front surface side, and then a friction stir welding step is performed on the butt portion J1 from the back surface side as shown in FIG. Before the friction stir welding process, thermal strain is applied to the joint portion in advance by the welding process. As a result, it is possible to prevent the joined first metal member 1 and the second metal member 2 from bending after the friction stir step, and to form a joint portion having excellent watertightness and airtightness. Further, the joint strength of the first metal member 1 and the second metal member 2 can be increased.

Further, according to the second embodiment, as shown in FIG. 10, burrs V are formed on the auxiliary members 10 divided by the friction stir welding step, but the auxiliary members 10 can be removed together with the auxiliary member 10 in the removing step. As a result, the work of removing the burr V can be easily performed.

[Third Embodiment]
Next, the joining method according to the third embodiment of the present invention will be described. As shown in FIG. 12, in the joining method according to the third embodiment, the auxiliary member 10 is arranged on both the first metal member 1 and the second metal member 2 in the arrangement step, and the first metal member with respect to the auxiliary member 10 is arranged. It differs from the first embodiment in that the contact ratio between 1 and the second metal member 2 is changed. Further, the rotation direction of the joining rotation tool F is also different from that of the first embodiment. The joining method according to the third embodiment will mainly explain the differences from the first embodiment.

The joining method according to the third embodiment includes a butt step, a welding step, a placement step, a friction stir step, and a removal step. Since the butt step and the welding step of the third embodiment are the same as those of the first embodiment, the description thereof will be omitted.

After welding the butt portion J1 from the surface side in the welding step, the first metal member 1 and the second metal member 2 are turned upside down and restrained on the upper surface of the gantry T. When the temperature of the joint portion drops after the welding step, the joint portion is distorted so as to have a convex shape toward the opposite side (back surface 1c, 2c side) of the weld metal W2. In this way, thermal strain is applied to the joint portion by the welding process.

As shown in FIG. 12, the arrangement step of the third embodiment is a step of bringing the back surface 1c of the first metal member 1 and the back surface 2c of the second metal member 2 into surface contact with the back surface 10c of the auxiliary member 10.
In the arrangement step of the third embodiment, about 90% of the auxiliary member 10 is arranged on the first metal member 1, and the remaining about 10% is arranged on the second metal member 2. That is, the auxiliary member 10 is arranged so as to slightly project toward the second metal member 2 with respect to the butt portion J1.
In the third embodiment, the auxiliary member 10 is arranged so that the auxiliary member 10 comes into surface contact with both the first metal member 1 and the second metal member 2, and when the removal step described later is performed. The auxiliary member 10 is adjusted so as not to remain on the second metal member 2 side (the side having a small contact area with the auxiliary member 10).

As shown in FIG. 13, the friction stir welding step is a step of joining the butt portion J1 between the first metal member 1 and the second metal member 2 by friction stir welding using the joining rotary tool F.
In the third embodiment, in order to rotate the joining rotation tool F clockwise, the spiral groove of the stirring pin F2 is formed counterclockwise from the base end to the tip end.

In the friction stir step of the third embodiment, the stirring pin F2 rotated clockwise is inserted from the surface 10b of the auxiliary member 10, and the insertion depth of the stirring pin F2 is set so as to reach the butt portion J1.
In the friction stir step of the third embodiment, only the stirring pin F2 rotated clockwise is inserted into the butt portion J1 and the metal member to be joined and the connecting portion F1 are moved while being separated from each other. In other words, friction stir welding is performed with the base end portion of the stirring pin F2 exposed.
Then, with the first metal member 1, the second metal member 2, and the auxiliary member 10 in contact with the stirring pin F2, the joining rotation tool F is moved from the front side to the back side in FIG. 13 along the butt portion J1. Move relative to each other. As a result, the butt portion J1 is friction stir welded. A plasticized region W1 is formed in the movement locus of the joining rotation tool F.
In the third embodiment, the traveling direction of the joining rotation tool F is set so that the auxiliary member 10 is located on the right side of the traveling direction of the joining rotation tool F. In the third embodiment, since the joining rotation tool F is rotated at high speed, burr V tends to be generated more on the flow side than on the shear side. Then, in the third embodiment, since the first metal member 1 side is the flow side, many burrs V are generated in the auxiliary member 10.

As shown in FIG. 14, the removing step is a step of removing the auxiliary member 10 from the first metal member 1. In the removing step, for example, the auxiliary member 10 is manually bent in a direction away from the first metal member 1 and removed from the first metal member 1.

Although the joint portion is distorted after the friction stir welding step, the first metal member 1 is as shown in FIG. 15 because the joint portion is preliminarily subjected to thermal strain by the welding step before the friction stir welding step. And the second metal member 2 become flat. Further, in the friction stir welding step, since the back surface side of the butt portion J1 is welded before the front surface side of the butt portion J1 is frictionally agitated, it is possible to prevent welding defects from occurring in the joint portion.

According to the joining method according to the third embodiment described above, the first metal member 1 and the second metal member 2 are joined in a plane shape, and in addition to the first metal member 1 and the second metal member 2, By simultaneously friction stir welding the auxiliary member 10, it is possible to prevent a metal shortage in the joint portion (plasticized region W1).

Further, in the third embodiment, as shown in FIG. 12, after performing a welding step on the butt portion J1 from the front surface side, a friction stir welding step is performed on the butt portion J1 from the back surface side as shown in FIG. Before the friction stir welding process, thermal strain is applied to the joint portion in advance by the welding process. As a result, it is possible to prevent the joined first metal member 1 and the second metal member 2 from bending after the friction stir step, and to form a joint portion having excellent watertightness and airtightness. Further, the joint strength of the first metal member 1 and the second metal member 2 can be increased.

Further, according to the joining conditions of the third embodiment, as shown in FIG. 13, since the rotation speed of the joining rotation tool F is set to be high, a large number of burrs V tend to occur on the flow side. That is, in the third embodiment, the rotation direction, the traveling direction, and the like (joining conditions) of the joining rotation tool F are set so that the burr V is formed more on the first metal member 1 side of the auxiliary member 10.
As a result, the burr V formed on the auxiliary member 10 is removed together with the auxiliary member 10 in the removing step, so that the work of removing the burr can be performed more easily.
Further, after the friction stir welding step, the end face of the auxiliary member 10 is inclined so that the plate thickness becomes thinner toward the butt portion J1. A removing device or the like may be used for the auxiliary member 10, but in the third embodiment, the auxiliary member 10 can be easily removed by hand.

Here, in the removal step of the second embodiment described above, it is necessary to remove the auxiliary members 10 and 10 on both sides of the butt portion J1. However, in the third embodiment, the arrangement position of the auxiliary member 10 is adjusted so that the auxiliary member 10 does not remain on the second metal member 2 side (the side where the contact area with the auxiliary member 10 is small) after the friction stir welding step. In the removal step, it is only necessary to remove the auxiliary member 10 on one side. As a result, the labor of the removal process can be reduced. Further, in the arranging process, the auxiliary member 10 is slightly projected to the second metal member 2 side (the other side) with the butt portion J1 sandwiched between them, so that the metal shortage at the joint portion can be prevented in a well-balanced manner and more reliably. it can.

1 1st metal member 2 2nd metal member 10 Auxiliary member F Rotation tool for joining (rotation tool)
F1 Connecting part F2 Stirring pin J1 Butting part V Bali W1 Plasticization area W2 Welded metal

Claims (5)

A joining method for joining a first metal member and a second metal member.
A butt step of abutting the first metal member and the second metal member to form a butt portion,
Welding process of welding from the surface side to the butt portion,
An arrangement step of turning over the first metal member and the second metal member and arranging the auxiliary member so as to make surface contact with the first metal member or the back surface of the second metal member.
The stirring pin of the rotation tool is inserted from the surface side of the auxiliary member while rotating, and only the stirring pin is brought into contact with the first metal member, the second metal member, and the auxiliary member along the butt portion. A friction stir step of joining the first metal member, the second metal member, and the auxiliary member by relatively moving the rotary tool.
A removal step of removing the auxiliary member on which burrs are formed from the first metal member or the second metal member, and
A joining method characterized by including. The joining method according to claim 1, wherein in the friction stir welding step, joining conditions are set so that burrs generated in the friction stir welding are formed on the auxiliary member. A joining method for joining a first metal member and a second metal member.
A butt step of abutting the first metal member and the second metal member to form a butt portion,
Welding process of welding from the surface side to the butt portion,
An arrangement step of turning over the first metal member and the second metal member and arranging an auxiliary member so as to make surface contact with both the first metal member and the back surface of the second metal member.
The stirring pin of the rotation tool is inserted from the surface side of the auxiliary member while rotating, and only the stirring pin is brought into contact with the first metal member, the second metal member, and the auxiliary member along the butt portion. A friction stir step of joining the first metal member, the second metal member, and the auxiliary member by relatively moving the rotary tool.
A removal step of removing the auxiliary member on which burrs are formed from the first metal member and the second metal member, and
Only including,
In the arrangement step, the auxiliary member is arranged on one of the first metal member and the second metal member, and is arranged so as to slightly project to the other side with the butt portion sandwiched between them.
The friction stir welding step is characterized in that the joining conditions are set so that the burrs generated in the friction stir welding are formed on either one of the first metal member and the second metal member of the auxiliary members. Joining method. With the weld metal formed in the butt portion in the welding process,
The joining method according to any one of claims 1 to 3 , wherein the plasticized region formed in the butt portion in the friction stir step is in contact with the plasticized region. A joining method for joining a first metal member and a second metal member.
A butt step of abutting the first metal member and the second metal member to form a butt portion,
Welding process of welding from the surface side to the butt portion,
An arrangement step of turning over the first metal member and the second metal member and arranging an auxiliary member so as to make surface contact with both the first metal member and the back surface of the second metal member.
The stirring pin of the rotation tool is inserted from the surface side of the auxiliary member while rotating, and only the stirring pin is brought into contact with the first metal member, the second metal member, and the auxiliary member along the butt portion. A friction stir step of joining the first metal member, the second metal member, and the auxiliary member by relatively moving the rotary tool.
A removal step of removing the auxiliary member on which burrs are formed from the first metal member and the second metal member, and
Only including,
With the weld metal formed in the butt portion in the welding process,
A joining method characterized in that the plasticized region formed in the butt portion in the friction stir step is in contact with the plasticized region .

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