JP2009106978A - Repairing method by friction stir welding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a repairing method for performing the consistent defect repair by friction stirring to a welded part having any defect caused during friction stir welding. <P>SOLUTION: A defect 91 is caused (2) in a welded part 90 during the friction stir welding (1). The friction stirring for repair is performed to the welded part (3) by using a friction stir rotary tool 60 for repair having the screw part 61 whose threading direction is opposite to that of a screw part 51 of a friction stir rotary tool 50 for welding, while rotating the friction stir rotary tool 60 for repair in the direction opposite to the rotational direction of the friction stir rotary tool 50 for welding (3). By performing the friction stirring by changing the position of occurrence of the defect 91 to the environment of high stirring pressure, the sound welded part 90 with the defect 91 diminished can be consistently obtained (4). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a repair method that eliminates defects such as cracks and internal defects in a joint in friction stir welding of two members.

  When friction stir welding is performed on the butt portion of two members, if a defect such as a surface crack or internal defect occurs, the defect is generally removed by cutting or the like in the repair. Repairing the repaired portion by MIG bonding is performed (see Patent Document 1 and Patent Document 2). In the case of MIG joining, there are cases in which repair work is required again due to the trouble of defect removal work, reduction in appearance due to joining, defects such as bubbles in the joint, and the like.

Also, for the defects that occurred during friction stir welding, when the same rotating tool is used again and the friction stirring is performed under the same conditions, the friction stirring is performed again in an environment where the conditions in which defects are likely to occur originally are prepared. It is extremely rare for defects to disappear completely.
JP 2000-334583 A JP 2002-59289 A

  It is an object of the present invention to provide a defect-free method in which defects generated in a friction stir welding are visually renovated and stably repaired by re-friction stirring on the joint. There is to do.

  In the present invention, two members are joined by friction agitation, and inserted into the joining part of the two members from the joining bead side of the joining part while rotating the rotating tool for friction stirring for repairing, Can be achieved by moving.

  According to the present invention, for the defect generated in the friction stir welding performed first, the friction stir rotation for repair having the screw portion of the first used friction stir rotating tool for joining and the screw portion in the reverse threading direction is used. Since the tool is moved while rotating in the opposite direction, the position of the generated defect in the cross-sectional direction is relatively changed to a position where no defect can be made, so the defect that occurred during the friction stir welding disappears. , Can stably supply a healthy joint.

  Hereinafter, an embodiment of a repair method by friction stir welding according to the present invention will be described with reference to the drawings.

  An embodiment of a repair method by friction stir welding of a joint according to the present invention will be described with reference to FIGS.

  In FIG. 1, in a state where two members 10 and 20 are butted on a gantry 30, the butted portion of the members 10 and 20 is used by using a welding friction stir rotating tool (hereinafter referred to as “joining rotating tool”) 50. Is joined by first friction stirring ((1) in FIG. 1). The screw part 51 of the rotary tool 50 shown in FIG. 1 is a left-hand screw. In this case, the rotation direction of the welding rotary tool 50 is clockwise when viewed from above the tool. Further, the joining direction (the direction in which the joining rotary tool 50 travels) is the direction from the front side to the back side of the paper.

  When the gap between the butted surfaces of the two members 10 and 20 is larger than the allowable value, or when the target position of the welding rotary tool 50 is deviated from the allowable value, a defect such as a surface crack or an internal defect in the bonded portion 90 91 occurs ((2) in FIG. 1). It is known that the position where the defect 91 is generated is a position on the left side in the traveling direction and in contact with the screw portion 51. This is because when the friction stir welding is performed with the left screw and the clockwise rotating tool 50 for welding, the left side region in the advancing (joining) direction has a low pressure distribution with respect to the internal stirring pressure, and the metal structure is sufficient. This is because the region is not stirred and is in a state where defects are likely to occur. On the other hand, it is known that the pressure distribution on the right side in the traveling direction is high and no defect occurs.

  Even when the repairing friction stirrer is performed in the same clockwise direction using the same welding rotary tool 50 used in the first friction stirrer as it is for the joint 90 in which the defect 91 occurs, the internal stir pressure is increased. Remains low so that defects are rarely eliminated completely.

  Therefore, a repairing friction stirring rotary tool (hereinafter referred to as “repairing rotary tool”) 60 in which the screw part 61 is a right-hand thread is used, and the rotation direction is a counterclockwise rotation as viewed from above. By performing frictional stirring ((3) in FIG. 1), frictional stirring is performed by changing the defect occurrence position to an environment with a high stirring pressure. If the range of the defect 91 is limited, the second friction stirrer is applied only to that region, but if it occurs along the joint 90, the joint joined by the first friction stirrer All 90 are traced in the same direction as the first friction stir was performed. By doing in this way, it becomes possible to obtain the repaired joint portion 90 in which the defect 91 has disappeared ((4) in FIG. 1). In addition, when repairing the joint by friction stirring using the repair rotary tool 60, a low pressure region is generated on the right side of the joint.

  FIG. 2 is a view of a state of friction stir welding ((1) in FIG. 2) and a state of repair friction stirring ((2) in FIG. 2) as viewed from above. It is possible to eliminate the defect 91 by reversing the screw rotation direction of the repair rotary tool 60 and the rotation direction of the joining rotary tool 50. Reference numerals 92 and 93 denote bonding beads.

  FIG. 3 illustrates a repair method in which the target position of the repair rotary tool 60 is shifted from the target position of the joint rotary tool 50 toward the defect occurrence position in order to perform stable defect repair. In the joint portion 90, the center position C2 of the repair rotary tool 60 is shifted from the center position C1 of the joint rotary tool 50 to the side where the defect 91 is generated by the center position deviation amount W, thereby joining the rotary tool for joining. The defect 91 generated at the position in contact with the 50 screw portions 51 falls within the range where the stirring action by the screw portion 61 of the repair rotary tool 60 is reliably reached. Therefore, friction stir can be reliably applied to the portion where the defect 91 is generated by the screw portion 61, and a stable defect repair can be performed for the joint portion 90. The amount of deviation is about 0.5 to 1 mm.

  FIG. 4 illustrates a repair rotary tool 60 having a screw portion 61 whose diameter is larger than that of the screw portion 51 of the joining rotary tool 50 in order to perform stable defect repair. By increasing the diameter of the threaded portion, the defect 91 that has occurred at the position in contact with the threaded portion 51 of the welding rotary tool 50 falls within the range in which the stirring action by the threaded portion 61 of the repairing rotating tool 60 is reliably reached. . Therefore, friction stir can be reliably applied to the portion where the defect 91 is generated by the screw portion 61, and the defect repair can be stably performed for the joint portion 90. The diameter is about 0.5 to 1 mm larger than the threaded portion 51 of the rotary tool 50. Further, in the case shown in FIG. 4, the center positions of both rotary tools are not misaligned, but it is obvious that they may be used in combination with such center positions.

Process drawing from friction stir welding to repair friction stir. Top view of friction stir welding and repair friction stir. The cross-sectional view of the state which shifted the insertion position of the friction stir rotating tool for repair to the defect side. The cross-sectional view at the time of defect repair when the diameter of the screw part of the friction stir rotating tool for repair is larger than the screw part of the friction stir rotating tool for joining.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,20: Member, 30: Stand 50: Friction stirring rotating tool for joining 51: Screw part of friction stirring rotating tool for joining 60: Friction stirring rotating tool for repairing 61: Screw part of friction stirring rotating tool for repairing 90: Joining Part 91: Defect 92, 93: Joining bead C1: Center position of the friction stir rotating tool 50 for joining C2: Center position of the friction stir rotating tool 60 for repair W Center position shift amount

Claims (4)

The two members are joined by the first friction stirrer,
When there is a defect in the joint part of the two members, the screw part of the friction stir rotating tool for joining used at the time of joining by the first friction stirrer from the joint bead side to the joint part is a screw. The second friction stirrer is performed while rotating the friction stir rotating tool for repair having a threaded part opposite in the cutting direction in a direction opposite to the rotating direction at the time of joining by the first friction stirrer,
Repair method for joints characterized by In the repair method of the junction part of Claim 1,
Applying the friction stir rotating tool for repair to the joint portion by shifting it from the passing position of the friction stir rotating tool for welding at the time of joining by the first friction stirring to the defect occurrence side,
Repair method for joints characterized by In the repair method of the junction part of Claim 1,
The screw part of the friction stir rotating tool for repair is larger in diameter than the screw part of the friction stir rotating tool for joining;
Repair method for joints characterized by In the repair method of the junction part of any one of Claims 1-3,
The second friction stirrer is performed by following a part or all of the joint portion joined by the first friction stirrer;
Repair method for joints characterized by

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