JP2007083257A - Friction stirring and joining method using double action type rotary tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a friction stirring and joining method capable of obtaining a sound joined state even when slight change of the prerequisite such as slight change in the plate thickness occurs. <P>SOLUTION: In the friction stirring and joining method, end faces of a first joining member and a second joining member consisting of an aluminum alloy plate placed on a backing jig 3 are butted to each other, and butted portions 23 are joined with each other. There are provided a large diameter part, and a small diameter probe 12 provided on the axis of rotation of a shoulder 11 forming an end face of the large diameter part. A double action type rotary tool 1 capable of changing the projection L from the shoulder 11 of the probe 12 is used, and after the double action type rotary tool 1 is inserted in the butted portions 23 in a rotating manner, the double action type rotary tool 1 is moved in the planar direction along the butted portions 23. A slight change to indicate a fine change of a state of the double action type rotary tool 1, the first joining member 21, the second joining member 22 or the backing jig 3 is measured, and the double action type rotary tool 1 is moved while changing the projection L of the probe 12 according to the result of measurement. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a friction stir welding method using a rotary tool in which a shoulder and a probe are double-acting.

  Recently, from the viewpoint of protecting the global environment or saving energy, the toxic gas and carbon dioxide emitted from automobiles has been screamed and fuel consumption has been improved. One way to achieve these is to reduce the weight of automobiles, that is, to use lightweight materials, and there is a great deal of investigation into the conversion of body and parts from steel to aluminum. There is a concept of tailored blanks in which different plates are joined and used for press molding in order to save materials as much as possible and to make the right parts in the right place.

  Steel plate tailored blanks have been put to practical use by laser welding and mash seam welding. In the case of an aluminum alloy, laser welding has problems such as high reflectivity of laser light, large variations depending on the surface state, and easily generating porosity, and a stable joint cannot be obtained. In the case of mash seam welding, in the case of an aluminum alloy, since heat can easily escape and only local melting can be performed, it is difficult to obtain a joint having a smooth surface that can withstand press forming.

  On the other hand, an aluminum alloy butt friction stir welding method has been reported as a joining method with low heat input and a low degree of softening and strain (Patent Document 1). This method is a method in which a soft material is abutted and constrained on a hard backing, and a hard pin type tool is inserted and moved while rotating at a high speed at the abutting part. is there. It is suitable for metals that are soft and have a low melting point, and is suitable for joining aluminum alloys. A stable joint characteristic can be obtained by manufacturing a tailored blank using this method (Patent Document 2).

  In an aluminum alloy tailored blank, the target plate thickness is about 0.7 to 3.0 mm. When joints of equal thickness or differential thickness butt are performed by a friction stir welding method in a particularly thin region within this range, a joining state that is not necessarily sound may be obtained. This is considered to be because, when the target plate thickness is thin, subtle changes in the plate thickness, subtle undulations of the backing jig, and the like greatly affect the joining state.

Japanese Patent No. 2712838 Japanese Patent No. 3262533

  The present invention has been made in view of such conventional problems, and provides a friction stir welding method capable of obtaining a sound joint state even if a minute change in a precondition such as a subtle change in plate thickness occurs. It is what.

The present invention is a friction stir welding method in which the end surfaces of two joining members made of an aluminum alloy plate having a thickness of 0.7 to 3 mm placed on a backing jig are butted and the butted portions are joined. There,
A double-acting rotary tool having a large-diameter portion and a small-diameter probe provided on the rotation shaft of the shoulder, which is the end face of the large-diameter portion, can change the amount of protrusion from the probe shoulder. ,
After inserting the double-acting rotary tool into the abutting portion while rotating the double-acting rotary tool, in moving the double-acting rotary tool in the plane direction along the abutting portion,
The double-acting rotary tool, the joining member, or the backing jig is measured for a minute change indicating a subtle change, and the amount of protrusion of the probe is changed according to the measurement result. The friction stir welding method is characterized in that the rotary tool is moved (Claim 1).

  In the friction stir welding method of the present invention, the double-acting rotary tool is positively employed. That is, a double-acting rotary tool having a large-diameter portion and a small-diameter probe provided on a rotation shaft of a shoulder that is an end face of the large-diameter portion, and capable of changing the amount of protrusion from the shoulder of the probe Is used. Then, after the double-acting rotary tool is rotated and inserted into the abutting portion, the double-acting rotary tool is moved in the plane direction along the abutting portion.

  Further, not only using the double-acting rotary tool, but also measuring a minute change indicating a subtle change in the state of the joining member or the backing jig, and depending on the measurement result, the probe protrudes. The double-acting rotary tool is moved while changing the amount. Therefore, the insertion depth of the probe can be finely adjusted according to the minute change, and a sounder joined state can be obtained as compared with the case where the fine adjustment is not performed. In particular, since the plate thickness of the joining member of the present invention is a thin plate of 0.7 to 3 mm, the above friction stir welding method is effective.

In the present invention, the thickness of the joining member is in the range of 0.7 to 3 mm. Note that the present invention can be applied not only when the two joining members to be joined have the same plate thickness but also when the plates having different plate thicknesses are to be abutted. The plate thickness is in the range of 0.7 to 3 mm.
When the plate thickness of the joining member is less than 0.7 mm, it is difficult to apply the friction stir welding method itself. On the other hand, when the plate thickness of the joining member exceeds 3 mm, there is a possibility that the effect of finely controlling the protruding amount of the probe of the double-acting rotary tool may not be sufficiently obtained.

The minute change is caused by fluctuations in the thickness of one or both of the joining members, fluctuations in the relief of the backing jig, load fluctuations in the direction in which the double-acting rotary tool is inserted into the joining member, the joining members or the double-acting It is preferably one of the temperature changes of the rotary tool.
These minute changes tend to affect the joining state when the joining member is a thin plate as described above. Therefore, it is preferable to control the protrusion amount of the probe in accordance with these minute changes.

  As a method for measuring the plate thickness variation, a non-contact type plate thickness meter such as an X-ray plate thickness meter, an ultrasonic plate thickness meter, a laser change meter, or a contact type plate thickness meter such as a roller type micrometer is used. There are methods such as moving with a double-acting rotary tool. As a method of measuring the undulation fluctuation of the backing jig, there is a method of using a sensor that detects displacement by a roller. As a method for measuring the load fluctuation in the direction in which the double-acting rotary tool is inserted into the joining member, there are a method using a load cell, a method using a differential pressure sensor using hydraulic pressure, air, and the like. As a method for measuring the temperature change of the joining member or the double-acting rotary tool, there is a method using a non-contact thermometer such as an infrared sensor or a contact thermometer such as a thermocouple embedded in the tool.

  A friction stir welding method according to an embodiment of the present invention will be described with reference to FIGS. In addition, this example shows one embodiment of the present invention, and the present invention is not limited to this.

Example 1
As shown in FIG. 1, in this example, the material 6111 alloy, which is the first joining member 21, grade T4, a 1 mm-thick plate (500 mmW × 1 mL), the material 6111 alloy, which is the second joining member 22, and grade T4. This is a friction stir welding method in which a plate (500 mmW × 1 mL) having a thickness of 2 mmt is placed on the backing jig 3, restrained by abutting the end surfaces in the width direction, and joining the butted portions 23.

The double-acting rotary tool 1 has a separate drive control in which the shoulder 11 and the probe 12 are coaxial, that is,
Each was configured to be capable of load control and position control, and to be configured so that the probe 12 could be moved forward and backward relative to the shoulder 11. As shown in FIG. 1, the hydraulic control device 6 that performs the separate drive control is electrically connected to the measurement devices 51 and 52 provided in the double-acting rotary tool 1, and the measurement is performed from the measurement devices 51 and 52. It was configured to perform control according to the result.

  In joining using such a friction stir welding apparatus 4, first, the double-acting rotary tool 1 is against the abutment surface 200 between the first joining member 21 and the second joining member 22. The rotation axis C is inclined toward the first bonding member 21 by an angle θ (θ = 5 degrees). Further, as shown in FIG. 3, the rotary tool 1 is arranged in a posture inclined by an angle α (α = 3 degrees) in a direction opposite to the moving direction A in the plane direction to be performed later. Then, the double-acting rotary tool 1 is inserted directly below the backing jig 3 while being rotated from the vertical direction to the abutting portion 23, and then along the abutting portion 23. The rotary tool 1 is moved in the plane direction. At this time, the rotational speed of the double-acting rotary tool 1 was 1500 rpm, and its moving speed, that is, the joining speed was 2 m / min.

  Conventionally, when butt joining is performed, a non-double-acting rotary tool in which the shoulder and the probe are fixed is moved under a fixed condition, or even if a double-acting rotary tool is used. After being inserted into the mating portion, the shoulder and the probe are fixed so as not to move and moved in the plane direction. On the other hand, in this example, a minute change indicating a subtle change in the state of the double-acting rotary tool 1, the first joining member, the second joining member, or the backing jig 3 is measured, and according to the measurement result. The double-acting rotary tool 1 is moved while changing the protruding amount of the probe 12.

  As shown in FIG. 1 and FIG. 2, the joint has a large-diameter portion 10 and a small-diameter probe 12 provided on a rotation shaft of a shoulder 11 that is an end face of the large-diameter portion 10. A double-acting rotary tool 1 that can change the protruding amount L of the 12 shoulders 11 is used. The shoulder 11 has a diameter D1 of 15 mm, and the probe 12 has a diameter D2 of 3 mm.

  Further, in this example, as shown in FIG. 1, a gantry-type friction stir welding apparatus 4 is used as the friction stir welding apparatus provided with the double-acting rotary tool 1. The friction stir welding apparatus 4 has a base plate that slides up and down on the gantry 40, and the base plate 41 so that the double-acting rotary tool 1 can be tilted + -15 degrees in the horizontal column direction of the gantry 40. In addition, a joining head 42 to which the double-acting rotary tool 1 is fixed is attached.

  As the minute change measurement, in this example, load control with a constant insertion depth of the joint portion is adopted, and the load measurement using a load cell is adopted for the measurement. In order to realize this measurement, the friction stir welding apparatus 4 to be described later is provided with measuring devices 51 and 52 configured to feed back the load cell and its value to the insertion depth for the large diameter portion 10 and the probe 12, respectively. The projection amount of the probe of the double-acting rotary tool 1 is changed based on the measurement result.

As shown in FIGS. 4 and 5, the specific action of the double-acting rotary tool 1 is such that the tip surface 120 of the probe 12 and the shoulder 11 are flush with each other at the start of joining, and the shoulder 11 joins the joining member. 6 (after 10 seconds from the contact of the shoulder 11), the probe 12 is protruded as shown in FIG. 6, and then the entire double-acting rotary tool 1 is moved along the abutting portion 23, and Joining was performed while minutely changing the protruding amount L of the probe 12 according to the measurement results of the measuring devices 51 and 52. At the joining end position, the double-acting rotary tool 1 was pulled upward while maintaining the protruding state of the probe 12.
As a result, at the joining end position, the portion where the probe 12 was present remained in the shape of a hole as in the case of using the fixed rotary tool. (Defects that continued in the longitudinal direction) and kissing bonds (unbonded portions on the back surface) could be prevented, and sound bonding was possible.

(Example 2)
In this example, a specific example of obtaining a tailored blank in which a hole does not remain at the joining end position by the friction stir welding method basically the same as in Example 1 is shown.
Using the same apparatus as in Example 1, it was performed under the same conditions (rotation speed, bonding speed, plate size) as in Example 1 until the vicinity of the joining end position was reached. The tip surface 120 of the probe 12 was retracted to the shoulder 11 surface from 30 mm before the joining end position, and the shoulder 11 surface was inserted 0.1 mm at the joining end position. As a result, at the joining end position, the portion where the probe 12 was present was blocked.
Thus, in this example, a tailored blank in which no hole remained at the end portion could be obtained. In other respects, the same effects as those of the first embodiment can be obtained.

Explanatory drawing which shows a friction stir welding apparatus. Sectional drawing which shows a double-acting rotary tool. Explanatory drawing which shows the angle with respect to the moving direction of a double acting rotary tool. Explanatory drawing which shows the double acting rotary tool at the time of a joining start. Explanatory drawing which shows the joining member heated with a shoulder. Explanatory drawing which shows the joining state which the probe protrudes.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Double acting rotary tool 10 Large diameter part 11 Shoulder 12 Probe 120 Tip surface 200 Butting surface 21 1st joining member 22 2nd joining member 23 Butting part 3 Backing jig | tool 4 Friction stir welding apparatus 40 Gantry 42 Joining head 6 Hydraulic control device

Claims (2)

A friction stir welding method in which end faces of two joining members made of an aluminum alloy plate having a thickness of 0.7 to 3 mm placed on a backing jig are joined, and the joined parts are joined.
A double-acting rotary tool having a large-diameter portion and a small-diameter probe provided on the rotation shaft of the shoulder, which is the end face of the large-diameter portion, can change the amount of protrusion from the probe shoulder. ,
After inserting the double-acting rotary tool into the abutting portion while rotating the double-acting rotary tool, in moving the double-acting rotary tool in the plane direction along the abutting portion,
The double-acting rotary tool, the joining member, or the backing jig is measured for a minute change indicating a subtle change, and the amount of protrusion of the probe is changed according to the measurement result. A friction stir welding method characterized by moving a rotary tool.   2. The minute change according to claim 1, wherein one or both of the joining members have a thickness variation, a backing jig has an undulation variation, a load variation in a direction in which the double-acting rotary tool is inserted into the joining member, and the joining. A friction stir welding method characterized in that it is either a member or a temperature change of the double-acting rotary tool.

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