JP4837752B2 - Friction stir welding end treatment method - Google Patents

Description

  The present invention relates to a processing method for closing a hole formed at the end of joining when materials to be joined are joined and integrated by a friction stir welding method.

  In recent years, a friction stir welding method has appeared as a new joining means that replaces welding and brazing of metal materials. This joining method is, for example, as disclosed in Japanese Patent Publication No. 7-505090, when a probe made of a material harder than the workpiece (rod-like object) is slidably contacted with the workpiece, Because the workpiece material is plastically fluidized by the frictional heat and pressure generated at the sliding contact part, the probe is embedded in the workpiece and can be moved through the workpiece in this embedded state. It is a thing that makes use of.

  For example, as shown in FIG. 1, when the metal plates (1) and (1) are brought into contact with each other, a protruding probe (21) is attached to the tip of the machining head (20) as a friction stir welding tool (2). The probe (21) is embedded by pressing it against the starting end of the joining line (L) while rotating the machining head (20) at a high speed, and along the joining line (L) as indicated by an arrow. Move. Thereby, the material of the metal plate (1) (1) is plastically flowed by frictional heat and pressure on the front side of the traveling probe (21), and gradually moves to the rear side of the probe (21) while being stirred and kneaded. Since this rear side loses frictional heat and rapidly cools and solidifies, the two metal plates (1) and (1) are joined together in a state where the metal materials are agitated and kneaded and are completely integrated.

  In this case, the temperature at which the metal material is plastically flowed is considerably lower than the melting point, and joining is in the category of solid-phase joining. Therefore, the heat input to the metal material is small throughout the joining process, and no stress is generated due to solidification shrinkage. Therefore, there is an advantage that deformation and cracking due to thermal strain in the vicinity of the joint are unlikely to occur. In addition, although the example which moves the process head side was shown in FIG. 1, there also exists the method of joining with the process head arrange | positioned in the fixed position, moving the to-be-joined material side conversely.

JP 7-505090 Gazette Japanese Patent Laid-Open No. 10-052771 Japanese Patent Laid-Open No. 02-197396

  However, in such friction stir welding, as shown in FIG. 2A, when the processing head (20) is pulled up at the joining end and the embedded probe (21) is pulled out, the probe is placed at the joining end. A punch hole (3) corresponding to (21) is generated, but since stress concentrates on the punch hole (3), the strength of the joined product is lowered and the appearance appearance is also deteriorated. There was a problem that various troubles were caused and the product value was lowered.

  In view of the above-described circumstances, an object of the present invention is to provide a processing method that can easily and surely block a hole formed at a joining end in friction stir welding and greatly improve the strength and appearance of a joined product. .

  In order to achieve the above object, the friction stir welding terminal processing method according to the first aspect of the present invention is a method of relatively advancing the processing head of the friction stir welding tool while being rotated in the embedded state, thereby joining the materials to be joined together. In friction stir welding that integrates joints, solder or brazing filler metal is filled in the hole formed by pulling up the processing head at the end of joining, and the solder or brazing filler metal is melted and solidified to be integrated into the workpiece. It is characterized by letting.

  According to this processing method, since the solder or brazing filler material filled in the hole at the end of friction stir welding is a low melting point material, the residual heat remaining in the material to be joined after friction stir welding, this residual heat and external heating, or external The filler can be easily melted only by heating, and a new surface can be formed at the hole position by solidification. Therefore, the obtained bonded product is excellent in appearance appearance due to disappearance of the original punched hole, and the strength is increased because the stress concentration at the punched hole position is eliminated.

  According to a second aspect of the present invention, in the friction stir welding termination processing method according to the first aspect, the hole is filled with Zn-Al based solder mainly composed of Zn. In this case, since the Zn-Al solder to be used has a particularly low melting point, if the hole is filled immediately after the end of the friction stir welding, the solder is melted only by the residual heat at the time of the friction stir welding remaining on the material to be joined. It is possible.

  According to a third aspect of the present invention, in the friction stir welding termination processing method of the first aspect, the hole is filled with an Al-Si-based or Al-Cu-based brazing material and heated and melted. In this case, since the melting point of the brazing material to be used is relatively high, it is necessary to heat it with a burner or the like after filling the punched hole. Less heat is required due to residual heat.

  According to the friction stir welding end treatment method according to the first aspect of the present invention, solder or brazing filler metal is filled in a hole formed at the end of joining between the materials to be joined by friction stir welding, and melted and solidified to be joined. Since it is integrated into the material, the hole can be easily and surely closed to provide a bonded product with excellent appearance and strength, and the processing efficiency is improved by utilizing the residual heat of friction stir welding as the heat source for melting. It is possible to improve.

  According to the second aspect of the present invention, in the above friction stir welding end treatment method, since the material filled in the hole has a particularly low melting point, this filling is performed immediately after the end of the friction stir welding, and the material to be joined Therefore, there is an advantage that the heat treatment can be shortened and the processing cost can be reduced by omitting external heating.

  According to the third aspect of the present invention, in the above-described processing method at the end of the friction stir welding, the material filled in the hole is melted by external heating, but heating is performed by filling and heating immediately after the end of the friction stir welding. The degree and time can be reduced.

It is a perspective view which shows joining of the metal plates by friction stir welding. An example of the processing method of the friction stir welding end point concerning this invention is shown, (A) figure is a vertical side view of a joined product which produced a punched hole at the joining end of friction stir welding, and (B) figure is the same product. FIG. 4C is a longitudinal side view of a state in which the solder hole or the soldering material is filled in the punched hole, and FIG.

  Hereinafter, an embodiment of the method for treating a friction stir welding terminal according to the present invention will be described in detail with reference to FIGS.

  As shown in FIG. 2 (A), as described above, the machining head (20) is placed at the end where the metal plates (1) and (1) made of aluminum or an alloy thereof are joined by friction stir welding (see FIG. 1). A state in which a punched hole (3) corresponding to the probe (21) is generated at the joining end of the obtained joined article (10) by extracting the probe (21) which has been pulled up and embedded is shown.

  In order to perform the processing of this joining termination, first, as shown in FIG. 2 (B), the hole (3) is filled with solder or brazing material (4a). Then, the filled solder or brazing material (4a) is melted and solidified. As a result, as shown in FIG. 2 (B), in the joined product (10), the hole (3) is filled with the solder or brazing material (4b) after melting and solidification, and the original hole (3) It has a uniform surface that has disappeared in shape and is excellent in appearance, and has high strength because there is no stress concentration at the hole position.

  Here, since the solder or brazing filler metal (4a) is a low melting point material, it can be easily melted by applying external heating with a burner or a heating iron after filling into the hole (3). The residual heat of friction stir welding can be used as a heat source for this melting. That is, in friction stir welding, frictional heat is generated along with the joining, and immediately after the joining is finished, the surrounding area of the hole (3) is considerably hot due to the residual heat remaining in the material. Can be melted with only residual heat without external heating. Moreover, even if the material cannot be melted only by the residual heat, if the external hole is heated after filling the hole (3) immediately after the end of joining, the degree and time of heating can be reduced because the residual heat is added. Processing efficiency is improved.

  Examples of the solder include Zn-Al-based, Zn-Sn-based, Zn-Pb-based, and Sn-Pb-based solder alloys. Among these, Zn-Al solder mainly composed of Zn (typical composition Zn 95 wt%, Al 5 wt%) has a very low melting point, and is filled in the hole 3 immediately after the end of the friction stir welding. In particular, it is particularly recommended because it can be reliably melted with only residual residual heat.

  Examples of the brazing material include alloys for brazing materials such as Al-Si and Al-Cu. These brazing materials generally have a melting point higher than that of solder and are difficult to melt only by the residual heat of friction stir welding, and therefore, it is preferable to melt them by heating with a burner or the like after filling the holes (3). However, even in this case, if filling and heating are performed immediately after the end of the friction stir welding, there is a residual heat of the friction stir welding, so that the heating can be reduced.

  In addition, as a solder or brazing material (4a) to be used, the pin-shaped thing was illustrated in FIG. 2, However, A granular or powder-like thing can also be used, and the hole (3) is in the form of a wire or a bar. It is also possible to insert. Thus, the filling amount of the solder or brazing material (4a) into the hole (3) should be set so that the surface after melting and solidification substantially matches the surface level of the material to be joined (1). is there.

1 ... Metal plate (material to be joined)
DESCRIPTION OF SYMBOLS 10 ... Joined article 2 ... Friction stir welding tool 20 ... Processing head 21 ... Probe 3 ... Punch hole 4a ... Filled solder or brazing material 4b ... After melting and solidification Solder or brazing material

Claims (8)

In friction stir welding, in which the processing head of the friction stir welding tool is rotated and moved relatively in the embedded state to join and integrate the materials to be joined together, in the punch hole generated by pulling up the processing head at the end of the joint The solder or brazing material is filled, and the solder or brazing material is melted and solidified by the residual heat of the friction stir welding remaining on the material to be joined and external heating by a burner or a heating iron to be integrated with the material to be joined. A method for treating a friction stir welding end. The processing method of the end of friction stir welding according to claim 1, wherein the hole is filled with solder or brazing material immediately after the end of friction stir welding. The friction stir welding termination method according to claim 1 or 2, wherein the punched hole is filled with Zn-Al solder mainly composed of Zn. The friction stir welding termination method according to claim 1 or 2, wherein the hole is filled with an Al-Si-based or Al-Cu-based brazing material. The filling amount of the solder or brazing material in the hole is set so that the surface after melting and solidification substantially matches the surface level of the material to be joined. Processing method. The processing method of the friction stir welding termination | terminus in any one of Claims 1-5 which fills a punching hole with a granular or powdery solder or brazing material. The method for treating a friction stir welding end point according to any one of claims 1 to 5, wherein the hole is filled with solder or brazing material in the form of a wire or bar. The friction stir welding termination method according to any one of claims 1 to 5, wherein the hole is filled with pin-shaped solder or brazing material.

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