Friction stir welding method and friction stir welding apparatus

Abstract

By appropriately setting the heat input for friction stir welding and increasing the welding speed, productivity can be improved. [Solution] The friction stir welding method includes determining the appropriate rotation speed of the jig for each of at least two relative moving speeds, determining the appropriate conditions for the appropriate rotation speed for a given relative moving speed based on the appropriate rotation speeds for each of the at least two relative moving speeds, and performing friction stir welding of the first member and the second member in a speed range where the relative moving speed exceeds 3 m / min, under conditions that satisfy the appropriate conditions.

Description

Technical Field

[0001] The present disclosure relates to a friction stir welding method and a friction stir welding apparatus.

Background Art

[0002] As a method of joining members to be joined, after inserting a cylindrical jig into the planned joining location of the members while rotating the cylindrical jig, the members to be joined are softened by relatively moving the members and the jig along the planned joining location, and the members are joined by stirring the softened members. Friction stir welding (FSW) is known. Friction stir welding enables joining without melting the members, and because it is less likely to cause defects such as deformation and shrinkage cavities and has high joining strength, it is expected to be applied in various fields, for example, when one or both of the members to be joined are aluminum die-cast materials.

[0003] Here, in friction stir welding, if the amount of heat input from the frictional heat generated by the rotation of the jig to the members to be joined is outside the appropriate range, the joining strength between the members may decrease. For example, if the amount of heat input is too much, excessive burrs may occur on the surface of the joined members. Also, if the amount of heat input is too little, defects may occur on the surface or inside of the members due to insufficient stirring. In contrast, for example, in Patent Documents 1 to 3, techniques for setting conditions such as the rotation speed and relative movement speed of the jig so that defects do not occur in the joined members and performing friction stir welding are disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0005] Friction stir welding can achieve stable joint strength compared to other joining methods that do not involve welding, such as mechanical joining methods like SPR (Self-Pierce Riveting) or FDS (Flow Drilling Screw), or chemical joining using adhesives. However, it is known that the joining speed is slower than that of joining methods such as welding. Therefore, in order to improve productivity in friction stir welding, it is necessary to increase the joining speed while appropriately setting the heat input.

[0006] The technology disclosed in Patent Document 1 involves performing a predetermined number of test welds of the members to be joined using a friction stir welding apparatus, setting lower and upper limits for the range of welding temperatures that can ensure the desired friction stir welding quality for each divided section under each welding condition (rotation speed and forward speed), acquiring a predetermined number of rotation speeds and forward speeds of the welding tool at that time to set a reference forward speed and a reference rotation speed, and then, when actually performing friction stir welding, acquiring the current welding temperature for each divided section, selecting the closest reference welding temperature to which the acquired current welding temperature belongs, selecting the reference forward speed corresponding to the selected reference welding temperature as the target value for the forward speed, and selecting the reference rotation speed corresponding to the selected reference welding temperature as the target value for the rotation speed. For this reason, it is necessary to perform a predetermined number of test welds each time to join certain members together. In addition, it is necessary to measure the current welding temperature when actually performing friction stir welding. Consequently, it is difficult to improve productivity.

[0007] Furthermore, the technology disclosed in Patent Document 2 optimizes processing conditions such as the specifications of the friction stir welding tool, the rotational speed of the tool, the welding speed of the tool, and the insertion depth of the tool to control the heat input to be approximately constant. However, the technology disclosed in Patent Document 2 controls the amount of heat input to the workpiece by directly feeding back the measured temperature of the joint or its vicinity during welding. This has limitations in increasing the welding speed (relative movement speed between the tool and the workpiece), making it difficult to improve productivity.

[0008] Furthermore, the technology disclosed in Patent Document 3 includes a step of forming a joint between materials to be joined by moving them relatively at a predetermined rotational speed and moving speed, checking whether there are defects opening on the surface of the materials to be joined or the joint, and whether there are internal spaces closed by the materials to be joined or the joint, in a cross section intersecting the longitudinal direction of the formed joint, and if it is determined that there are no defects or internal spaces, reducing the rotational speed or increasing the moving speed. For this reason, each time two members are joined together, it is necessary to repeat joining, checking, and changing the conditions until it is determined that there are no defects or internal spaces, making it difficult to improve productivity.

[0009] This disclosure is made in view of the above circumstances, and the purpose of this disclosure is to provide a friction stir welding method and a friction stir welding apparatus that can improve productivity by increasing the joining speed while appropriately setting the amount of heat input. [Means for solving the problem]

[0010] To solve the above problems, according to one aspect of this disclosure, a friction stir welding method is provided, which involves rotating the jig while inserting the jig into the planned joining portion between a first member and a second member, and moving the first member and the second member relative to the jig along the planned joining portion to soften the first member and the second member and friction stir welding the first member and the second member, the method comprising: determining an appropriate rotation speed of the jig for at least two relative moving speeds; determining appropriate conditions for the appropriate rotation speed for the relative moving speed based on the appropriate rotation speed for at least two relative moving speeds; and performing friction stir welding of the first member and the second member in a speed range where the relative moving speed exceeds 3 m / min, under conditions that satisfy the appropriate conditions.

[0011] Furthermore, in order to solve the above problems, according to another aspect of this disclosure, a friction stir welding apparatus is provided which inserts a jig into a planned joining portion between a first member and a second member while rotating the jig, and softens the first member and the second member by moving the jig relative to the planned joining portion, thereby friction stir welding the first member and the second member, the first member and the second member, and friction stir welding the first member and the second member, the apparatus comprising: a storage unit that records appropriate conditions for the appropriate rotation speed for the relative moving speed, determined based on the appropriate rotation speed for at least two relative moving speeds; and a control unit that sets the relative moving speed and rotation speed of the jig in a speed range where the relative moving speed exceeds 3 m / min, under conditions that satisfy the appropriate conditions, and controls the operation of the friction stir welding apparatus. [Effects of the Invention]

[0012] As explained above, this disclosure makes it possible to improve productivity by increasing the bonding speed while appropriately setting the heat input. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram showing an example of the configuration of a friction stir welding apparatus according to one embodiment of the present disclosure. [Figure 2] It is an explanatory diagram showing the operation of a friction stir welding device according to an embodiment of the present disclosure. [Figure 3] It is an explanatory diagram showing the operation of a friction stir welding device according to an embodiment of the present disclosure. [Figure 4] It is an explanatory diagram showing the temperature change of the jig during welding. [Figure 5] It is a flowchart showing a procedure for obtaining appropriate conditions in a friction stir welding method according to an embodiment of the present disclosure. [Figure 6] It is an explanatory diagram showing an example of an appropriate range of appropriate rotational speeds with respect to the relative movement speed according to an embodiment of the present disclosure. [Figure 7] It is an explanatory diagram showing an example of an appropriate range of appropriate rotational speeds with respect to the relative movement speed according to an embodiment of the present disclosure. [Figure 8] It is a flowchart showing an example of a joining process in a friction stir welding method according to an embodiment of the present disclosure.

Mode for Carrying Out the Invention

[0014] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[0015] <<1. Configuration of Friction Stir Welding Device>> First, a configuration example of a friction stir welding device to which the friction stir welding method of the present disclosure is applicable will be described. However, as long as the first member and the second member to be joined and the jig inserted into the joining planned portion of the first member and the second member are relatively movable, the configuration of the friction stir welding device excluding the control device is not particularly limited. Hereinafter, a configuration example of the friction stir welding device will be briefly described.

[0016] FIG. 1 shows a configuration example of a friction stir welding device. The friction stir welding apparatus 1 shown in Fig. 1 is configured such that the jig 27 is displaced along the planned welding portion 35 in a state where a part of the first member 31 and a part of the second member 33 to be joined are overlapped and placed. Note that the friction stir welding apparatus may be configured such that the first member and the second member are displaced while the position of the jig is fixed, or may be configured such that the jig, the first member, and the second member are all displaced.

[0017] The friction stir welding apparatus 1 includes a movable part 3 installed on a base 11, a head 5 that supports and holds a jig 27 at the tip of the movable part 3, and a control device 50 that controls the drive of the friction stir welding apparatus 1. The movable part 3 includes a support part 13, a first arm 15a, a second arm 15b, a third arm 15c, and a fourth arm 15d. The support part 13, the first arm 15a, the second arm 15b, the third arm 15c, and the fourth arm 15d are connected to each other so as to be relatively rotatable.

[0018] The connecting part 17a between the base 11 and the support part 13 has a first motor 19a, and the base 11 and the support part 13 rotate relative to each other around the axis of the motor shaft of the first motor 19a. The connecting part 17b between the support part 13 and the first arm 15a has a second motor 19b, and the support part 13 and the first arm 15a rotate relative to each other around the axis of the motor shaft of the second motor 19b. The connecting part 17c between the first arm 15a and the second arm 15b has a third motor 19c, and the first arm 15a and the second arm 15b rotate relative to each other around the axis of the motor shaft of the third motor 19c.

[0019] The connecting part 17d between the second arm 15b and the third arm 15c has a fourth motor 19d, and the second arm 15b and the third arm 15c rotate relative to each other around the axis of the motor shaft of the fourth motor 19d. The connecting part 17e between the third arm 15c and the fourth arm 15d has a fifth motor 19e, and the third arm 15c and the fourth arm 15d rotate relative to each other around the axis of the motor shaft of the fifth motor 19e.

[0020] The fourth arm 15d has a head support portion 21 that supports the head 5. The head support portion 21 includes a vertical movement drive unit (not shown) that displaces the head 5 in the vertical direction. The vertical movement drive unit includes, for example, a ball screw, a linear guide, and a motor, and moves the head 5 up and down by the rotation of the motor.

[0021] Head 5 comprises a holder 23, a jig drive motor 25, and a jig 27. The jig drive motor 25 and the jig 27 are connected by a rotating shaft (not shown) and held in the holder 23. The jig 27 is rotatably held in the holder 23 and rotates around the axis driven by the jig drive motor 25.

[0022] The control device 50 functions as a device that controls the drive of the friction stir welding apparatus 1 by having one or more CPUs (Central Processing Units) or other processors execute a computer program. The computer program is a computer program that causes the processor to execute the operations that the control device 50 is to perform, which will be described later. The computer program executed by the processor may be recorded on a recording medium that functions as a storage unit 53, which will be described later, or it may be recorded on another recording medium built into the control device 50 or on any recording medium that can be attached externally to the control device 50.

[0023] The recording medium for storing computer programs may include magnetic media such as hard disks, floppy disks, and magnetic tapes; optical recording media such as CD-ROMs, DVDs, and Blu-ray®; magneto-optical media such as floppy disks; memory elements such as RAM and ROM; flash memory such as USB memory and SSDs; and other media capable of storing programs.

[0024] The control device 50 comprises a control unit 51 and a storage unit 53. The storage unit 53 is a memory element such as RAM or ROM, and records the appropriate conditions for the appropriate rotational speed of the jig 27 in relation to the relative moving speed of the first member 31 and the second member 33 and the jig 27. The control unit 51 sets either the relative moving speed or the rotational speed of the jig 27 in a speed range where the relative moving speed exceeds 3 m / min, under conditions that satisfy the appropriate conditions, and controls the operation of the friction stir welding apparatus 1. The method for determining the appropriate conditions recorded in the storage unit 53 and the details of the friction stir welding process using these appropriate conditions by the control unit 51 will be explained in detail later.

[0025] <<2. Operation of the friction stir welding apparatus>> Next, I will explain the operation of the friction stir welding apparatus.

[0026] Figures 2 and 3 show a schematic diagram of the operation of the friction stir welding apparatus 1. As shown in the diagram, the jig 27 includes a shoulder portion 28 and a connecting pin 29. The connecting pin 29 is a small-diameter portion that protrudes downward from the center of the lower end surface of the jig 27, and the end surface around the connecting pin 29 constitutes the shoulder portion 28.

[0027] The control device 50 rotates the jig 27 while lowering the head 5, inserting the joining pin 29 of the jig 27 into an arbitrary starting position of the planned joining portion 35 of the first member 31 and the second member 33 to be joined, and pressing the shoulder portion 28 against the vicinity of the planned joining portion 35 to apply pressure (joining begins). As a result, frictional heat causes the first member 31 and the second member 33 near the planned joining portion 35 to heat up and soften.

[0028] Subsequently, the control device 50 rotates the jig 27 and presses it against the joint 35, moving the first member 31 and the second member 33 relative to the jig 27 along the joint 35 (during joining). As a result, the first member 31 and the second member 33 near the joint 35 are agitated (plastically flowed), and the first member 31 and the second member 33 are joined together.

[0029] When the jig 27 reaches any desired end position on the joining portion 35, the control device 50 raises the head 5 to detach the jig 27 from the first member 31 and the second member 33, and stops the rotation of the jig 27 (joining complete). In this way, the first member 31 and the second member 33 are joined without melting.

[0030] In Figures 1 and 2, the overlapping portion between the side surface of the first member 31 and the side surface of the second member 33 is shown as the planned joining portion 35. However, the planned joining portion 35 may also be the portion where the first member 31 and the second member 33 are butted together.

[0031] Figure 4 is an explanatory diagram showing the difference in heat input between cases where the joining is performed correctly and cases where it is not. In Figure 4, the solid line shows the change in tip temperature of the jig 27 when the joining is performed correctly, and the dashed line shows the change in tip temperature of the jig 27 when the joining is not performed correctly. The dashed line shows an example where the rotation speed is higher than the example shown by the solid line.

[0032] As shown in Figure 4, if the rotation speed of the jig 27 is too high, the jig 27 will overheat due to frictional heat. In this case, the amount of heat input to the first member 31 and the second member 33 will be excessive, and burrs will be generated at the joint. If the amount of heat input is insufficient, defects such as internal voids may occur. In friction stir welding, the amount of heat input mainly depends on the rotation speed of the jig 27 and the relative moving speed between the members to be joined and the jig 27. In this embodiment, the joining speed of friction stir welding is increased by appropriately setting this amount of heat input.

[0033] <<3.Friction stir welding method>> Next, the friction stir welding method according to this embodiment will be described.

[0034] In this embodiment, the friction stir welding method includes the steps of determining the appropriate conditions for the appropriate rotational speed of the jig 27 with respect to the relative moving speed between the first member 31 and the second member 33 and the jig 27, and performing friction stir welding under conditions that satisfy the appropriate conditions in a speed range where the relative moving speed exceeds 3 m / min.

[0035] (Calculation of appropriate conditions) Figure 5 is a flowchart showing the procedure for determining the appropriate conditions. First, the user determines the appropriate rotational speed of the jig 27 for at least two relative moving speeds (step S1). At this time, at least two relative moving speeds may both be in the speed range exceeding 3 m / min, or at least one may be 3 m / min or less. Alternatively, at least two relative moving speeds may both be in the speed range of 3 m / min or less. Conventionally, there have been few examples of friction stir welding being put into practical use at speeds exceeding 3 m / min, and it is easy to determine the appropriate rotational speed of the jig 27 for proper welding at speeds of 3 m / min or less.

[0036] The number of relative movement speeds used to determine the appropriate rotational speed of the jig 27 may be at least two, but may also be three or more. The more relative movement speeds used to determine the appropriate rotational speed of the jig 27, the more accurately the appropriate conditions can be determined. However, if the number of relative movement speeds used to determine the appropriate rotational speed of the jig 27 is too many, the amount of work required to determine the appropriate conditions will increase. Therefore, the number of relative movement speeds used to determine the appropriate rotational speed of the jig 27 may be two or three.

[0037] The appropriate rotational speed of the jig 27 with respect to the relative moving speed between the first member 31 and the second member 33 and the jig 27 can be determined, for example, by performing friction stir welding using an actual machine and evaluating the bonding state.

[0038] Next, the user determines the appropriate conditions for the appropriate rotational speed for each of the at least two relative moving speeds determined in step S1, based on the appropriate rotational speed of the jig 27 for each relative moving speed (step S3). The appropriate conditions are those that allow the amount of heat input per unit volume to the first member 31 and the second member 33 due to frictional heat between the first member 31 and the second member 33 and the jig 27 to be appropriate, with the appropriate rotational speed increasing as the relative moving speed increases. In this embodiment, the appropriate conditions are determined by finding an appropriate range for the ratio of relative moving speed to appropriate rotational speed. These appropriate conditions may be an appropriate range for the ratio of the appropriate rotational speed to the relative moving speed, or an appropriate range for the ratio of relative moving speed to appropriate rotational speed. The appropriate rotational speed of the jig 27 may be replaced with the rotational movement distance of the outer circumference of the connecting pin 29 of the jig 27. Furthermore, the appropriate conditions can be expressed as a formula for calculating the amount of heat input to the jig 27 due to frictional heat, which is shown as a function of the moving speed and rotational speed of the jig 27, and may be automatically calculated by a computer or calculated by a user.

[0039] Figures 6 and 7 show an example of the appropriate range of rotational speed for a given relative moving speed. Figure 6 shows the evaluation results of the relationship between the relative moving speed and the appropriate rotational speed when friction stir welding a first member 31 and a second member 33, with the relative moving speed in the range of 1,000 mm / min to 3,000 mm / min and the rotational speed of the jig 27 set to three stages, R1, R2, and R3.

[0040] In the example shown in Figure 6, the ratio of the appropriate rotational speed to the relative travel speed at which a good joint is achieved (appropriate rotational speed / relative travel speed) was P1 to P2. When the appropriate rotational speed was replaced with the rotational travel distance of the outer circumference of the joining pin 29 of the jig 27, the ratio of the appropriate rotational travel distance to the relative travel speed at which a good joint is achieved (appropriate rotational travel distance / relative travel speed) was X1 to X2.

[0041] When the ratio of the appropriate rotational speed to the relative movement speed was less than P1 (when the ratio of the appropriate rotational movement distance to the relative movement speed was less than X1), the movement speed of the jig 27 was too fast relative to the rotation of the jig 27, resulting in a gap inside the joint. On the other hand, when the ratio of the appropriate rotational speed to the relative movement speed exceeded P2 (when the ratio of the appropriate rotational movement distance to the relative movement speed exceeded X2), the heat input due to friction was excessive, resulting in excessive burrs. Therefore, it is understood that even when the relative movement speed changes, by setting the rotational speed of the jig 27 to a rotational speed that satisfies the appropriate conditions, the heat input is appropriately set and a good joint condition can be obtained.

[0042] Figure 7 shows an example where the appropriate conditions were set by further expanding the speed range of relative movement speed to the high-speed range, based on the calculation results of the appropriate range shown in Figure 6. In the example shown in Figure 7, the appropriate rotational speed (OK) is set to a range where the ratio of the appropriate rotational speed to the relative movement speed is P1 to P2 (the ratio of the appropriate rotational movement distance to the relative movement speed is X1 to X2) within the range of 1,000 to 15,000 mm / min.

[0043] Next, the user determines the appropriate holding time according to the number of rotations of the jig 27 when it is pressed against the first member 31 and the second member 33 at the start of joining (step S5). The holding time is the time from when the joining pin 29 is inserted into the planned joining portion 35 of the first member 31 and the second member 33 while rotating the jig 27 at the start of joining, until the relative movement of the jig 27 begins. If the holding time is too short, defects such as internal gaps may occur at the joining start position. On the other hand, if the holding time is too long, excessive burrs may be generated at the joining start position, or the total joining time may become longer. Therefore, appropriately setting the holding time of the jig 27 at the start of joining can be an important factor in ensuring proper joining.

[0044] For example, when performing the process in step S1 above, the user may also change the holding time of the jig 27 to determine the appropriate holding time. Generally, the smaller the rotational speed of the jig 27, the more time it is necessary to ensure a holding time, while if the rotational speed of the jig 27 is large, the holding time may be omitted (appropriate holding time = 0 seconds). For example, in the examples in Figures 6 and 7 above, the appropriate holding time is 1 second when the rotational speed of the jig 27 is R1 mm / min, and the appropriate holding time is 0 seconds when the rotational speed of the jig 27 is R2 mm / min or more.

[0045] Next, the user records the information on the appropriate conditions obtained in step S3 and the appropriate holding time obtained in step S5 in the storage unit 53 of the control device 50 of the friction stir welding apparatus 1 (step S7).

[0046] (Implementation of friction stir welding) The control unit 51 of the control device 50 of the friction stir welding apparatus 1 controls the drive of the friction stir welding apparatus 1 using information on appropriate conditions and appropriate holding time recorded in the storage unit 53, and joins the first member 31 and the second member 33 by friction stir welding in a speed range where the relative movement speed exceeds 3 m / min. The information on appropriate conditions and appropriate holding time is determined according to the first member 31 and the second member 33 to be joined and is recorded in the storage unit 53 in advance.

[0047] When the relative movement speed between the first member 31 and the second member 33 and the jig 27 is kept constant during friction stir welding, the rotation speed of the jig 27 is set to an appropriate rotation speed that satisfies the appropriate conditions, and the holding time of the jig 27 at the start of welding is set to an appropriate holding time. Then, as illustrated in Figures 2 and 3, the jig 27 is moved relative to the part to be joined 35 and the first member 31 and the second member 33 are joined by friction stir welding.

[0048] On the other hand, the relative moving speed between the first member 31 and the second member 33 and the jig 27 may be changed depending on the way the first member 31 and the second member 33 abut or overlap at the planned joining portion 35 of the first member 31 and the second member 33, or whether the planned joining portion 35 of the first member 31 and the second member 33 is straight or curved. In this embodiment, the appropriate conditions for the appropriate rotation speed of the jig 27 in a wide range of relative moving speeds from low to high are determined and recorded in the storage unit 53. Therefore, the control unit 51 can perform friction stir welding while changing the relative moving speed of the jig 27 and setting the rotation speed of the jig 27 to an appropriate rotation speed that satisfies the appropriate conditions.

[0049] Figure 8 shows an example of processing by the control unit 51 when the relative movement speed of the jig 27 is changed. First, the control unit 51 reads the control condition information and sets the rotation speed of the jig 27, the holding time, and the relative movement speed at the start of joining (step S11).

[0050] Next, the control unit 51 drives the friction stir welding apparatus 1 according to the set rotation speed and holding time of the jig 27 and starts the joining process (step S13). For example, while rotating the jig 27 at the set rotation speed, the control unit 51 inserts the joining pin 29 of the jig 27 into the starting position of the planned joining portion 35 of the first member 31 and the second member 33, and presses the shoulder portion 28 of the jig 27 against the planned joining portion 35. After inserting the jig 27, the control unit 51 starts the relative movement of the jig 27 once the set holding time has elapsed.

[0051] Next, the control unit 51 controls the drive of the friction stir welding apparatus 1 according to the set rotation speed and relative movement speed of the jig 27 (step S15). As a result, the jig 27 rotates at an appropriate rotation speed and moves along the planned joining portion 35 of the first member 31 and the second member 33, and the joining of the first member 31 and the second member 33 progresses.

[0052] Next, the control unit 51 determines whether or not to change the relative movement speed or rotation speed of the jig 27 (step S17). For example, if the line of the planned joining portion 35 (planned joining line) is bent or curved, it may be necessary to slow down the relative movement speed due to reasons such as the operability of the mechanism that relatively displaces the position of the jig 27. For example, before joining begins, the control unit 51 acquires information on the shape of the planned joining line of the planned joining portion 35 and the relative movement speed for each section of the planned joining line, along with information on the start and end positions of the planned joining portion 35 of the first member 31 and the second member 33. The control unit 51 refers to this information and determines whether or not to change the relative movement speed.

[0053] Furthermore, the information acquired in advance may not be information on the relative movement speed for each section of the planned joining line, but rather information on the rotational speed of the jig 27 for each section of the planned joining line.

[0054] If the control unit 51 determines that the relative movement speed or rotation speed of the jig 27 should be changed (S17 / Yes), it refers to the information on appropriate conditions and sets the relative movement speed and rotation speed of the jig 27 to satisfy the appropriate conditions (step S19). After that, the control unit 51 returns to step S15. On the other hand, if the control unit 51 does not determine that the relative movement speed or rotation speed of the jig 27 should be changed (S17 / No), it determines whether or not to terminate the joining process (step S21). For example, the control unit 51 determines that the joining process is terminated when the position of the jig 27 reaches a preset termination position.

[0055] If the control unit 51 does not determine that the joining is complete (S21 / No), it returns to step S15. On the other hand, if the control unit 51 determines that the joining is complete (S21 / Yes), it raises the jig 27 to remove it from the first member 31 and the second member 33, and stops the rotation of the jig 27 (step S23).

[0056] <<4. Effects>> As described above, the friction stir welding method according to this embodiment includes determining the appropriate rotational speed of the jig 27 for at least two relative moving speeds, determining appropriate conditions for the appropriate rotational speed for a given relative moving speed based on the appropriate rotational speeds for at least two relative moving speeds, and performing friction stir welding of the first member 31 and the second member 33 in a speed range where the relative moving speed exceeds 3 m / min, under conditions that satisfy the appropriate conditions. Therefore, depending on the first member 31 and the second member 33 to be joined, generalized appropriate conditions over a wide speed range can be determined from the appropriate rotational speed of the jig 27 at at least two relative moving speeds, and the joining speed can be increased. Thus, productivity can be improved by increasing the joining speed while appropriately setting the heat input.

[0057] Furthermore, in the friction stir welding method according to this embodiment, an appropriate range for the ratio of the relative movement speed of the jig 27 to the appropriate rotational speed can be determined as an appropriate condition. This makes it easy to set the appropriate rotational speed of the jig 27 when the relative movement speed of the jig 27 is increased over a wide range.

[0058] Furthermore, in the friction stir welding method according to this embodiment, at least two relative moving speeds used to determine the appropriate rotational speed of the jig 27 may all be 3 m / min or less. Since friction stir welding with a relative moving speed of 3 m / min or less of the jig 27 has been put into practical use, the appropriate conditions can be accurately determined from the appropriate rotational speed of the relative moving speed in this speed range.

[0059] Furthermore, in the friction stir welding method according to this embodiment, the relative movement speed or rotation speed of the jig 27 may be changed while friction stir welding is being performed, and the rotation speed and relative movement speed of the jig 27 may be set to satisfy appropriate conditions. This makes it possible to appropriately set the amount of heat input in each section, even when the joining conditions change for each section of the planned joining portion 35 of the first member 31 and the second member 33, thereby improving productivity while maintaining an appropriate joining state.

[0060] Furthermore, the friction stir welding method according to this embodiment may further include determining an appropriate holding time corresponding to the number of rotations of the jig 27 when inserting the jig 27 into the planned joining portion 35 while rotating the jig 27. This makes it possible to prevent defects such as burrs and voids from occurring at the joining start position.

[0061] Furthermore, the friction stir welding apparatus 1 according to this embodiment includes a storage unit 53 that records the appropriate conditions for the appropriate rotation speed for a relative moving speed, which are determined based on the appropriate rotation speeds for at least two relative moving speeds. The control unit 51 sets the relative moving speed and rotation speed of the jig 27 under conditions that satisfy the appropriate conditions in the speed range where the relative moving speed exceeds 3 m / min, and controls the operation of the friction stir welding apparatus 1. This makes it possible to drive the friction stir welding apparatus 1 according to generalized appropriate conditions over a wide range of speeds, thereby increasing the welding speed. Therefore, productivity can be improved by increasing the welding speed while appropriately setting the heat input.

[0062] While preferred embodiments of the present disclosure have been described in detail above with reference to the attached drawings, the present disclosure is not limited to such examples. It is clear to any person with ordinary skill in the art to which the present disclosure belongs that various modifications or alterations can be conceived within the scope of the technical idea described in the claims, and these will naturally also be understood to fall within the technical scope of the present disclosure. For example, the functions, etc., included in each component or step, etc., can be rearranged in a logically consistent manner, and multiple components or steps, etc., can be combined into one or divided into two.

[0063] For example, the control unit 51 may keep the relative movement speed of the jig 27 constant while friction stir welding is being performed, and change the rotation speed of the jig 27 to an appropriate rotation speed that satisfies the appropriate conditions. For example, if the required joint strength changes partially, or if the shape or composition of the first member 31 and the second member 33 changes partially, the appropriate conditions for each condition may be recorded in advance in the storage unit 53, and the rotation speed of the jig 27 may be changed while keeping the relative movement speed constant. This makes it possible to continuously perform friction stir welding even if the required joint strength changes, or if the shape or composition of the first member 31 and the second member 33 changes, thereby improving productivity.

[0064] Furthermore, the technology disclosed herein can also be realized as a computer program that causes a computer to function as the control device 50 described above, and as a non-temporary tangible recording medium on which the computer program is recorded. [Explanation of Symbols]

[0065] 1:Friction stir welding equipment 3: Moving part 5: Head 21: Head support section 23: Holder 25: Jig drive motor 27: Jig 28: Shoulder section 29: Connecting pin 31: First component 33: Second component 35: Planned joint 50: Control device 51: Control Unit 53: Storage section

Claims

1. A friction stir welding method is provided in which the jig is rotated and inserted into the planned joining portion between the first member and the second member, and the first member and the second member and the jig are moved relative to each other along the planned joining portion, thereby softening the first member and the second member and friction stir welding the first member and the second member, Determine the appropriate rotational speed of the jig for each of at least two relative moving speeds, Based on the appropriate rotational speeds for each of the at least two relative moving speeds, the appropriate conditions for the appropriate rotational speeds for the relative moving speeds are determined, The friction stir welding of the first member and the second member is performed in a speed range where the relative movement speed exceeds 3 m / min, under conditions that satisfy the appropriate conditions. A friction stir welding method, including the method described above.

2. The friction stir welding method according to claim 1, wherein the appropriate conditions are determined to be an appropriate range for the ratio of the relative moving speed of the jig to the appropriate rotational speed.

3. The friction stir welding method according to claim 1, wherein at least two of the relative moving speeds are all 3 m / min or less.

4. The friction stir welding method according to claim 1, wherein, during the friction stir welding, the relative moving speed of the jig is changed and the rotation speed of the jig is set to the appropriate rotation speed that satisfies the appropriate conditions.

5. The friction stir welding method according to claim 1, wherein the rotational speed of the jig is changed and the relative moving speed of the jig is set to the relative moving speed that satisfies the appropriate conditions, while the friction stir welding is being performed.

6. The friction stir welding method according to claim 1, wherein, during the friction stir welding, the relative movement speed of the jig is kept constant, and the rotational speed of the jig is changed to the appropriate rotational speed that satisfies the appropriate conditions.

7. The friction stir welding method according to claim 1, further comprising determining an appropriate holding time corresponding to the number of rotations of the jig when inserting the jig into the planned joining portion while rotating the jig.

8. In a friction stir welding apparatus, the jig is rotated while the jig is inserted into the planned joining portion between the first member and the second member, and the first member and the second member are moved relative to the jig along the planned joining portion to soften the first member and the second member, thereby friction stir welding the first member and the second member, A storage unit that records the appropriate conditions for the appropriate rotation speed for the relative moving speed, which are determined based on the appropriate rotation speed for each of at least two relative moving speeds, A control unit that sets the relative movement speed and rotation speed of the jig in a speed range where the relative movement speed exceeds 3 m / min, under conditions that satisfy the appropriate conditions, and controls the operation of the friction stir welding apparatus, A friction stir welding apparatus equipped with the following features.

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