JP2016129904A - Jointing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a jointing method that can provide preferable jointing even when a gap occurs in a butting part between base materials.SOLUTION: The jointing method includes: a step of filling a bulk material 8 into the gap between the base materials when a pair of base materials 5, 5 is butted to each other; and a step of jointing the butting part between the base material and the bulk material with friction stirring using a tool 1 including a probe part and a shoulder part provided at both ends of the probe part, where the center position of the tool is positioned on a side where a movement direction of an outer marginal part of the tool is directed in an opposite direction relative to a travelling direction of the tool more than the center in a width direction of the gap.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a joining method for joining base materials by friction stir welding.

  As one of the joining methods for joining the butt portions of the base materials, there is friction stir welding (FSW). In the friction stir welding, a friction stir welding tool having a rod-like probe protruding is used. By pressing the abutting portion of the base material while rotating the probe, friction heat is generated in the abutting portion, and the probe is immersed in the abutting portion softened by the frictional heat. After immersion, the base material is joined by rotating the probe to cause plastic flow around the probe, stirring and mixing, and moving the probe along the joining line of the butting portion.

  Further, as a friction stir welding tool for performing friction stir welding, there is a tool in which a shoulder having a diameter larger than that of the probe is provided at both ends of the probe, and the probe and the shoulder are configured to rotate integrally.

  When performing friction stir welding with the friction stir welding tool described above, by pressing the probe to the joining start end of the butting portion, and rotating the butting portion so as to be pinched by a shoulder from both the upper and lower surfaces, After the frictional heat is generated and softened in the butt portion, the friction stir welding tool is pulled so as to move along the joining line, so that the probe is immersed in the butt portion and friction stir welding is performed.

  In the friction stir welding, since the gap existing in the butt portion causes a defect, it is necessary to perform temporary attachment by arc welding or the like so that no gap is generated in the butt portion.

  However, when long base materials are joined together, it is difficult to eliminate a gap generated in the abutting portion because the base materials have initial deformation such as bending and waviness. When friction stir welding is performed with a gap in the butted portion, a shortage of the base material that fills the gap is insufficient, resulting in a bonding defect such as a hole being created at the location where the bonding is performed. There is a risk of causing it.

  In Patent Document 1, an intermediate plate is interposed between the hollow members, and the hollow members are arranged so that the end surfaces of the hollow members respectively face both surfaces of the intermediate plate. A configuration is disclosed in which an agitating pin is pressed against an end face of the intermediate plate, and the abutting portion between the hollow shape member and the intermediate plate is friction-stir joined. However, in Patent Document 1, since friction stir welding is performed aiming at the center of the intermediate plate, there is a possibility of causing a bonding defect and it is considered that the breaking strength is low.

JP 2009-6396 A

  In view of such a situation, the present invention provides a joining method capable of satisfactory joining even when a gap is generated in a butt portion of a base material.

  The present invention includes a step of filling a gap between the base materials with a bulk material when a pair of base materials are abutted, and a tool having a probe portion and a shoulder portion provided at both ends of the probe portion. And joining the abutting portion between the material and the bulk material by friction stir, and the center position of the tool is closer to the outer edge of the tool than the center in the width direction of the gap. The present invention relates to a joining method located on the side where the moving direction is the opposite direction.

  Further, the present invention relates to a joining method in which the bulk material is composed of a plurality of plate materials having different widths and lengths, and the plurality of bulk materials are filled in accordance with the shape of the gap.

  Furthermore, the present invention relates to a joining method in which the bulk material is a powder material, and the bulk material is filled in the gap.

  According to the present invention, a step of filling a gap between the base materials with a bulk material when a pair of base materials are abutted, and a tool having a probe portion and a shoulder portion provided at both ends of the probe portion, Joining the abutting portion between the base material and the bulk material by friction stirring, and the center position of the tool is the outer edge of the tool with respect to the traveling direction of the tool rather than the center in the width direction of the gap Since the moving direction of the part is located on the opposite side, the bonding material that is insufficient due to the gap is filled with the bulk material, and it is possible to suppress the bonding defect due to the shortage of the bonding material and to improve the breaking strength, An excellent effect that the state can be improved is exhibited.

It is a perspective view which shows the tool used for the joining method which concerns on the Example of this invention. It is the schematic explaining joining of the base material by the said tool. (A) is explanatory drawing which shows the state which made the center of a tool correspond with the centerline of a bulk material, (B) is description which shows the state which has located the center of a tool in the Ret side rather than the centerline of a bulk material. (C) is an explanatory view showing a state where the center of the tool is positioned on the Adv side with respect to the center line of the bulk material. It is the graph which put together the test result of the side bending test with respect to the test piece which performed friction stir welding on different conditions.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, referring to FIG. 1, a tool which is a tool for joining base materials by friction stir welding will be described. The tool 1 is attached to a friction stir welding apparatus (not shown), and the friction stir welding is performed by moving the tool 1 along the joining line while rotating by the friction stir welding apparatus. It is like.

  The tool 1 includes a cylindrical probe 2 and shoulders 3 and 3 that are attached to both ends of the probe 2 and are concentric with the probe 2. The shoulders 3 and 3 have a cylindrical shape having a diameter larger than that of the probe 2, for example, about twice the diameter of the probe 2, and end faces 4 and 4 facing the shoulders 3 and 3 are center axes of the probe 2. It is perpendicular to.

  The probe 2 has, for example, screw portions (not shown) at both ends and is screwed into screw holes (not shown) drilled in the shoulders 3 and 3, thereby The shoulders 3 and 3 are integrated. At this time, the screw portion of the probe 2 is formed in a direction to be tightened by a frictional force received from a base material 5 (described later) when the tool 1 is rotated.

  A groove 6 is formed on the entire peripheral surface of the probe 2 over the entire surface. In FIG. 1, the groove 6 has a screw shape, but the groove 6 may have another shape. Further, in the drawing, the groove 6 is shown as a left and right reverse screw at both ends of the probe 2.

  Tapered portions 7 and 7 are formed on the outer periphery of the shoulders 3 and 3 on the probe 2 side. The distance between the end faces 4 and 4 is slightly smaller than the thickness of the base material 5, and the distance between the outer peripheral edges of the tapered portions 7 and 7 is larger than the thickness of the base material 5. It has become.

  Next, referring to FIG. 2, the friction stir welding using the tool 1 will be described. In the present embodiment, the case where the groove shape is I-shaped will be described.

  In FIG. 2, 5 indicates a base material made of a material having a low melting point such as aluminum, an aluminum alloy, or copper. In this embodiment, a gap is formed between the base materials 5, 5, and the gap is a plate-like material having the same material as the base materials 5, 5 and the same thickness as the base material 5. Bulk material 8 is filled. In FIG. 2, 9 is a bead generated after friction stir welding, and 11 and 11 are joining lines when the base materials 5 and 5 are brought into contact with each other via the bulk material 8.

  When the bulk material 8 is filled between the base materials 5 and 5, the base materials 5 and 5 and the bulk material 8 are temporarily fixed by arc welding. By temporarily fixing the bulk material 8, misalignment between the base materials 5 and 5 and the bulk material 8 during friction stir welding is prevented. In FIG. 2, reference numeral 12 denotes a temporary attachment portion when arc welding is performed.

  When performing friction stir welding of the base materials 5 and 5 using the tool 1, first, the tool 1 is moved to the welding start end (left side with respect to the paper surface in FIG. 2) by a friction stir welding apparatus (not shown). . Further, the base materials 5 and 5 are set in a friction stir welding apparatus.

  Next, the height of the tool 1 is set so that the height positions of the upper and lower surfaces of the starting ends of the base materials 5 and 5 and the bulk material 8 coincide with the tapered portions 7 and 7 of the shoulders 3 and 3. Adjust. When the height adjustment of the tool 1 is completed, the tool 1 is rotated at a predetermined rotation speed, and the tool 1 is moved to the end side at a predetermined speed. For example, the rotational speed of the tool 1 is 230 rpm, and the traveling speed of the tool 1 is 150 mm / min.

  When the tool 1 is moved, the starting ends of the base materials 5, 5 and the bulk material 8 are guided to the tapered portions 7, 7 and are forced into the shoulders 3, 3. By the rotation of the tool 1, frictional heat is generated between the shoulders 3, 3 and the base materials 5, 5 and the bulk material 8, and the base materials 5, 5 and the bulk material 8 are softened by the frictional heat. .

  Further, by pressing the probe 2 against the base material 5, 5 and the starting end of the bulk material 8, the probe 2 is immersed in the base material 5, 5 and the bulk material 8, Thus, plastic flow is generated, and the material around the probe 2 is guided to the groove 6 and stirred, and stirring and mixing are performed.

  In this state, the base material 5, 5 and the bulk material 8 are agitated by moving the tool 1 along the joining lines 11, 11. By filling the bulk material 8 between the base materials 5 and 5, even when a gap is generated between the base materials 5 and 5, the gap is filled with the bulk material 8, and friction stir welding is performed. A good bonded state can be obtained.

  In the present embodiment, in the friction stir welding of the base materials 5 and 5 and the bulk material 8, the bulk material 8 is interposed at the abutting portion of the base materials 5 and 5, so that the joining line 11 is 2 There will be one. Therefore, the positional relationship between the joining lines 11 and 11 and the tool center O of the tool 1 is important.

  3A to 3C show the approximate position of the tool center O of the tool 1 with respect to the longitudinal center line 13 of the bulk material 8, that is, the center in the width direction of the gap between the base materials 5 and 5. ing.

  In this embodiment, the side on which the moving direction of the outer edge portion of the tool 1 is the forward direction with respect to the traveling direction of the tool 1 is referred to as Advanced side (Adv side), and the moving direction of the outer edge portion of the tool 1 The side in which the direction is the opposite is referred to as Retrieving side (Ret side). That is, as shown in FIG. 3A to FIG. 3C, when the tool 1 rotates counterclockwise, the right side is the Adv side and the left side is relative to the traveling direction of the tool 1. On the Ret side.

  FIG. 3A shows a state in which the tool center O of the tool 1 coincides with the longitudinal center line 13 of the bulk material 8, that is, coincides with the middle of the joining lines 11 and 11. 3B shows a state in which the tool center O of the tool 1 is positioned (offset) on the Ret side with respect to the longitudinal center line 13 of the bulk material 8, and FIG. The tool center O of the tool 1 is positioned (offset) on the Adv side with respect to the longitudinal center line 13 of the bulk material 8.

In this embodiment, the position of the tool center O of the tool 1 with respect to the joining lines 11 and 11 is varied, and friction stir welding is performed under a plurality of conditions, and a plurality of types of test pieces created for each condition are used. A side bending test was performed, and the opening lengths of cracks generated in the test pieces during the side bending test were compared.
FIG. 4 is a graph summarizing the opening lengths of cracks generated in each test piece.

  In order to create a test piece, when the width of the bulk material 8 is 3 mm and the tool center O of the tool 1 is made to coincide with the longitudinal center line 13, the tool center O is separated from the longitudinal center line 13. When the tool center O is shifted by 1 mm to the Adv side, when the tool center O is shifted by 2 mm from the longitudinal center line 13 to the Adv side, when the tool center O is shifted by 1 mm from the longitudinal center line 13 to the Ret side, When the center O is shifted 2 mm from the longitudinal center line 13 to the Ret side, when the tool center O is shifted 3 mm from the longitudinal center line 13 to the Ret side, the tool center O is moved from the longitudinal center line 13. Friction stir welding was performed for the case of shifting 4 mm to the Ret side.

  Similarly, when the width of the bulk material 8 is 5 mm and the tool center O of the tool 1 is aligned with the longitudinal center line 13, the tool center O is shifted from the longitudinal center line 13 to the Adv side by 1 mm. When the tool center O is shifted by 1 mm from the longitudinal center line 13 to the Ret side, when the tool center O is shifted by 2 mm from the longitudinal center line 13 to the Ret side, the tool center O is moved to the longitudinal direction. Friction stir welding was performed for the case where the direction center line 13 was shifted by 3 mm from the direction center line 13 to the Ret side. A side bending test was performed using four test pieces prepared under the above-mentioned 12 kinds of conditions.

  In FIG. 4, the bar graph shows the maximum value of the opening length of the cracks generated in the four test pieces by the side bending test. The thick line on the left is the side bending test result of the test piece with the width of the bulk material 8 being 3 mm, and the right thin line is the side bending test result of the test piece with the width of the bulk material 8 being 5 mm.

In FIG. 4, the plot shows the average of the opening lengths of the cracks generated in the four test pieces by the side bending test. The rhombus plot shows the result when the width of the bulk material 8 is 3 mm, and the square plot shows the result when the width of the bulk material 8 is 5 mm.
In FIG. 4, a thick broken line indicates an approximate curve of the average opening length of cracks when the width of the bulk material 8 is 3 mm, and a thin broken line indicates cracks when the width of the bulk material is 5 mm. An approximate curve of average aperture length is shown.

  In FIG. 4, the opening length of 12 mm indicates a state in which the test piece was broken without bending as a result of the side bending test.

  As shown in FIG. 4, when the tool center O of the tool 1 is aligned with the longitudinal center line 13 of the bulk material 8, and the tool center O of the tool 1 is more than the longitudinal center line 13. In the case of being positioned on the Adv side, in each case, there is a test piece that is broken without bending, and the average opening length of the crack is also large.

  On the other hand, when the tool center O of the tool 1 is positioned on the Ret side with respect to the longitudinal center line 13 of the bulk material 8, there is no specimen that is broken without bending, and the average opening of cracks The length is also smaller than when the tool center O is aligned with the longitudinal center line 13 or when it is positioned on the Adv side of the longitudinal center line 13.

  In addition, when the width of the bulk material 8 is 3 mm and the tool center O of the tool 1 is positioned 3 mm away from the longitudinal center line 13 of the bulk material 8 toward the Ret side, four tests are performed. There were no cracks in any of the pieces.

  As described above, when the bulk material 8 is interposed between the base materials 5 and 5 and the two joining lines 11 and 11 exist at the butt portion, the tool 1 when performing friction stir welding is used. It was found that a good joining result can be obtained by positioning the tool center O at the Ret side with respect to the longitudinal center line 13 of the bulk material 8.

  Further, it is understood that a better bonding result can be obtained by using the bulk material 8 having a width of 3 mm and shifting the tool center O of the tool 1 by 3 mm from the longitudinal center line 13 to the Ret side. It was.

  As described above, in this embodiment, when a gap is generated between the base materials 5 and 5 when the base materials 5 and 5 are brought into contact with each other, the same material and the same material as the base material 5 are provided in the gap. Friction stir welding is performed by filling a bulk material having a thickness of 5 mm.

  Accordingly, since the bonding material that is insufficient due to the gap between the base materials 5 and 5 is filled with the bulk material 8, it is possible to suppress bonding failure such as generation of holes due to insufficient bonding material.

  Further, when the bulk material 8 is filled in the gap, the two joining lines 11 exist at the butt portion. When the friction stir welding is performed, the tool center O of the tool 1 is set. By placing the bulk material 8 on the Ret side with respect to the longitudinal center line 13, that is, by shifting the joining line 11 (groove) to the Adv side, the strain that the joining material receives during agitation increases. , Stirring and mixing are promoted. Accordingly, the breaking strength is improved as compared with the case where the friction stir welding is performed along the longitudinal center line 13, and the joining state can be improved. It should be noted that the distance by which the tool center O is displaced from the longitudinal center line 13 is not more than half the diameter of the probe 2.

  In the present embodiment, the bulk material 8 filled between the base materials 5 and 5 is a plate having a constant width over the entire length, but the bulk material 8 has other shapes. There may be. For example, a plurality of plate-like materials having different widths and lengths may be prepared as the bulk material 8 and the plurality of bulk materials 8 may be filled in accordance with the shape of the gap between the base materials 5 and 5. Then, the powdered bulk material 8 may be filled in the gap between the base materials 5 and 5 without any gap. Further, a mold of the gap may be taken by brazing, the bulk material 8 may be prepared according to the mold, and the gap may be filled.

  By filling the bulk material 8 with no gaps in the gap, it is possible to more effectively prevent a shortage of bonding material at the time of friction stir welding.

  Further, in the present embodiment, the friction stir welding in the I-shaped groove has been described, but it is needless to say that the friction stir welding method of the present embodiment can be applied to other groove shapes. .

1 Tool 2 Probe 3 Shoulder 5 Base Material 8 Bulk Material 11 Joining Line 13 Longitudinal Center Line

Claims (3)

  A step of filling a gap between the base materials with a bulk material when a pair of base materials are brought together, and a tool having a probe portion and a shoulder portion provided at both ends of the probe portion, the base material and the bulk And joining the abutting portion with the material by friction stirring, and the moving position of the outer edge of the tool is opposite to the traveling direction of the tool than the center of the gap in the width direction of the tool. A joining method that is located on the direction side.   The joining method according to claim 1, wherein the bulk material is composed of a plurality of plate materials having different widths and lengths, and the plurality of bulk materials are filled in accordance with the shape of the gap.   The joining method according to claim 1, wherein the bulk material is a powder material, and the gap material is filled with the bulk material.

Images