JP2006239734A - Weld joint and method for forming the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a weld joint and a method for forming the weld joint which can prevent the deterioration of fatigue characteristics. <P>SOLUTION: The invented weld joint has weld metal portion 3 which is formed by fusion welding of two metal pieces 1 and 2 to be joined and then subjected to a friction stir process. After the two metal pieces 1 and 2 are fused by a fusion welding method, the probe 8 of a friction stir welding tool 6 being rotated is embedded in the weld metal portion 3 of both metal pieces 1 and 2 to be joined, and both metal pieces 1 and 2 to be joined and the friction stir welding tool 6 are moved relatively, while rotating the probe 8, and then the weld joint is formed by friction-stirring the weld metal portion 3 of both metal pieces 1 and 2 to be joined. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a welded joint and a method for forming the welded joint.

  In this specification and claims, the term “aluminum” includes aluminum alloys in addition to pure aluminum.

  In various industries such as the automobile industry, the construction industry, the electrical equipment industry, and the aerospace industry, various products are formed by welding metal joining materials. In general, fusion welding methods such as TIG and MIG are widely used for welding metal workpieces. In these fusion welding methods, welding such as blow holes, poor fusion, cracks, etc. are welded to the weld metal part of the welded joint. Defects may occur. In addition, the weld metal part of the weld joint is a cast structure generated by melting and re-solidification, and the crystal grain size is very large compared to the base material. Further, welding defects such as blowholes, poor fusion, and cracks, and coarse crystal grains are factors that reduce the fatigue characteristics of the welded joint. Moreover, when the welding speed is increased, an undercut that causes the toe portion of the weld bead to be recessed is generated and the fatigue strength of the welded joint is reduced, or the weld bead surface is uneven. May occur and the appearance may deteriorate.

  As a method of correcting the undercut of the weld bead toe and the shape defect of the surface of the weld bead, after welding the two metal workpieces by the fusion welding method, the shaping tool is attached to the weld bead surface of both workpieces and Friction heat is generated by moving relative to the periphery of the weld bead toe, and the shaping tool is moved while plastic fluidizing the weld bead surface and the periphery of the weld bead toe by this friction heat. A method of smoothly shaping the shape of the bead surface and the weld bead toe is known (see Patent Document 1).

However, the method described in Patent Document 1 cannot reduce weld defects such as blowholes, poor fusion, and cracks in the weld metal part, and cannot refine coarse crystal grains.
JP 2003-53586 A

  An object of the present invention is to provide a welded joint that can solve the above-described problems and prevent deterioration of fatigue characteristics, and a method for forming the welded joint.

  In order to achieve the above object, the present invention comprises the following aspects.

  1) A welded joint in which a weld metal part formed by melting and welding two metal workpieces is friction stir using a probe of a friction stir welding tool.

  2) The welded joint according to 1) above, wherein the two materials to be joined are made of aluminum.

  3) The welded joint according to 1) or 2) above, wherein a part of the weld metal in the weld metal part that is 1/2 or more of the thickness of the material to be joined is frictionally stirred.

  4) After welding two metal workpieces by the fusion welding method, insert the friction stir welding tool probe into the weld metal part of both workpieces while rotating the probe. A method for forming a welded joint, characterized by frictionally stirring the weld metal parts of both of the workpieces by relatively moving both of the workpieces and the friction stir welding tool.

  5) The method for forming a welded joint according to 4) above, wherein the two materials to be joined are made of aluminum.

  6) At the time of welding by the fusion welding method, an extra height of 1 mm or more is formed, and the shoulder of the rotor of the friction stir welding tool is extra at the time of friction agitation of the weld metal parts of both materials to be joined. The method for forming a welded joint according to 4) or 5) above, wherein the welded joint is pressed against the weld.

  7) The method for forming a welded joint according to any one of 4) to 6) above, wherein the length of the probe of the friction stir welding tool is set to ½ or more of the thickness of the material to be joined.

  8) Any one of the above 4) to 7), wherein the two materials to be joined are plate-shaped, both the materials to be joined are melt welded from both sides, and the molten metal part is frictionally stirred from one side of both materials to be joined. A method for forming a welded joint according to claim 1.

  9) The two materials to be joined are plate-shaped, both the materials to be joined are melt-welded from one side, and the molten metal part is friction-stirred from one side where the melt-welding is performed on both materials to be joined 4) to 7) A method for forming a welded joint according to any one of the above.

  10) The method for forming a welded joint according to any one of 4) to 7) above, wherein the two materials to be joined are cylindrical.

  11) The method for forming a welded joint according to 10) above, wherein a metal annular support member is disposed inside the two materials to be joined so as to straddle both the materials to be joined.

  12) The method for forming a welded joint according to the above 11), wherein the annular support member is friction stir welded to both the welded materials at the time of friction stirring of the weld metal portions of the both welded materials.

  13) It is formed by welding a plurality of metal plate-shaped workpieces, and a welded joint according to any one of the above 1) to 3) is formed between adjacent workpieces. Board that has been.

  14) It is formed by welding a plurality of metal cylindrical pipe constituent members, and a welded joint according to any one of the above 1) to 3) is formed between adjacent pipe constituent members. Piping.

  15) The pipe according to 14) above, in which a gas or a liquid is circulated.

  16) The piping according to 15) above, wherein the gas is hydrogen gas.

  17) By welding at least two metal container components that are formed of a cylindrical body and a closing plate that closes at least one end opening of the body, and are shaped in the longitudinal direction of the body. The weld joint according to any one of 1) to 3) above, wherein each container component member has a cylindrical peripheral wall portion, and between the peripheral wall portions of adjacent container component members. A container that is formed.

  18) The container according to 17) above, wherein a metal annular support member is disposed on the inner side of the peripheral wall portions of the adjacent container constituent members so as to straddle the peripheral wall portions of the two container constituent members.

  19) The container according to 18) above, wherein the support member is friction stir welded to the peripheral wall portions of both container constituent members.

  20) The container according to any one of 17) to 19) above, which is filled with a gas or a liquid.

  According to the weld joint of 1) above, since the weld metal part formed by melting and welding two metal workpieces is friction stir using the probe of the friction stir welding tool, welding Welding defects such as blowholes, poor fusion, and cracks in metal parts are reduced, and crystal grains in the weld metal parts are refined to, for example, about 20 μm. Therefore, fatigue characteristics such as fatigue strength and elongation of the welded joint are improved. Moreover, when the product which has this welded joint is used for the use which hydrogen gas contacts, the hydrogen embrittlement resistance characteristic of a welded joint will improve.

  According to the welded joint of 3) above, the fatigue characteristics and the hydrogen embrittlement resistance are reliably improved.

  According to the method for forming a welded joint of 4) above, after welding two metal workpieces by fusion welding, while rotating the probe of the friction stir welding tool to the weld metal portion of both workpieces The weld metal part of both the welded materials is frictionally stirred by moving the both welded materials and the friction stir welding tool relative to each other while rotating the probe. It becomes possible to form a welded joint with few weld defects such as holes, poor fusion, and cracks. Moreover, since the weld metal part is frictionally stirred, the crystal grains of the weld metal part are refined to about 20 μm, for example. Therefore, fatigue characteristics such as fatigue strength and elongation of the formed welded joint are improved. In addition, since this method performs friction stir after welding two metal workpieces by fusion welding, the gap between the two workpieces is compared with the case of friction stir welding of the two workpieces. The degree of freedom increases. Furthermore, when a product having a welded joint formed by this method is used for an application where hydrogen gas contacts, the hydrogen embrittlement resistance of the welded joint is improved.

  According to the method for forming a welded joint described in 6) above, the surface finishing of the metal product having the formed welded joint can be easily performed. In other words, the probe of the friction stir welding tool is embedded in the weld metal part of both workpieces while rotating, and both the workpiece and the friction stir welding tool move relatively while rotating the probe. By doing so, when the weld metal parts of both materials to be welded are frictionally stirred, thinning occurs in the weld metal part due to the influence of the shoulder of the rotor of the friction stir welding tool pressed against the surface of the molten metal part, The thickness of the weld metal part may be thinner than the thickness of the material to be joined. In this case, in order to make the surface of the product flush, the surface of the entire material to be joined must be subjected to a surface finishing process, for example, by cutting, which is troublesome. However, a height of 1 mm or more is formed at the time of welding by the fusion welding method, and the shoulder portion of the rotor of the friction stir welding tool is piled up at the time of friction stir of the weld metal portion of both materials to be joined. If it presses, even if thickness reduction arises in a weld metal part by the influence of a shoulder part, it can prevent that the thickness of a weld metal part becomes thinner than the thickness of a to-be-joined material. Therefore, even when the surface of the product is flush, only the surface of the weld metal portion may be subjected to surface finishing by, for example, cutting, and the work is facilitated.

  According to the method for forming a welded joint of 7) above, the fatigue characteristics and hydrogen embrittlement resistance of the formed welded joint are reliably improved.

  According to the method for forming a welded joint of the above 10), it is possible to reduce the weight of the metal product having the welded joint formed by this method. That is, when two cylindrical metal workpieces are friction stir welded by a butt joint, it is known that welding defects such as blow holes, poor fusion, cracks, and coarse crystal grains do not occur at the joint. However, during friction stir welding, a relatively large load is applied from the outside and the material to be joined may be deformed. To prevent this deformation, both the materials to be joined are placed inside the materials to be joined. It is necessary to arrange a metal annular support member so as to straddle the material. However, in this case, the weight of the obtained metal product increases. On the other hand, according to the method 10), the two cylindrical members are previously welded by the fusion welding method, and the rigidity of the welded joint is improved, so that the annular support member becomes unnecessary. Further, even when an annular support member is used as in the above method 11), a lighter one than the annular support member used in the friction stir welding can be used as the annular support member, and thus obtained. It is possible to reduce the weight of metal products.

  According to the weld joint forming method of the above 12), since the annular support member is friction stir welded to both the cylindrical workpieces, the pressure resistance in the radial direction of both cylindrical workpieces is improved.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same part and the same thing through all drawings, and the overlapping description is abbreviate | omitted.

Embodiment 1
This embodiment is shown in FIGS. 1 to 3 and is a welded joint formed between two plate-shaped workpieces. In the description of the first embodiment, the upper and lower sides and the left and right sides in FIG.

  FIG. 1 shows a welded joint, and FIGS. 2 and 3 show a method for forming a welded joint.

  In FIG. 1, the welded joint is made of two aluminum plate-like materials (1) and (2) having the same thickness, but the side edges of each other are joined together and melt welded from both the upper and lower sides. The part (3) is frictionally stirred from the upper surface side to a depth of 1/2 or more of the thickness of the materials to be joined (1) and (2) by using the probe of the friction stir welding tool. The friction stirrer is indicated by (4). The depth of the friction stirrer (4) is 1/2 or more of the thickness of the materials to be joined (1) and (2).

  Next, a method for forming a welded joint will be described with reference to FIGS.

  First, two plate-like materials (1) and (2) having the same thickness are prepared, and the side edges of both materials to be joined (1) and (2) are arranged to be I-shaped grooves ( (See FIG. 2 (a)).

  Both the joined materials (1) and (2) are made of aluminum, for example, any one of JIS A2000 alloy, JIS A5000 alloy, JIS A6000 alloy and JIS A7000 alloy. Both the joined materials (1) and (2) may be formed of the same material or may be formed of different materials. Moreover, the thickness of both the joined materials (1) and (2) is, for example, 4 mm or more.

  Next, both the materials to be joined (1) and (2) are welded by one layer from one side, here the upper side, by an appropriate fusion welding method such as TIG or MIG. At the time of welding from this single side, a surplus (5) having a height of 1 mm or more is formed (see FIG. 2 (b)). Next, both the materials to be joined (1) and (2) are welded in one layer from the other surface side, here the lower surface side, by an appropriate fusion welding method such as TIG or MIG. At the time of welding from the other surface side, a surplus (5) having a height of 1 mm or more is formed. Note that the surplus (5) may be formed only at the time of welding from at least one of the surfaces. By melting and welding both the joined materials (1) and (2) from both sides, a molten metal portion (3) is formed over the entire thickness of both the joined materials (1) and (2) (FIG. 2 (c)). reference).

  Next, using the friction stir welding tool (6), the weld metal part (3) is friction stir from one side, here the upper side, of both the workpieces (1) and (2). The friction stir welding tool (6) includes a cylindrical rotor (7) in which a small-diameter portion (7a) is integrally formed coaxially with a tapered portion at a tip portion, and a small-diameter portion of the rotor (7) ( 7a) is provided with a pin-shaped probe (8) integrally formed coaxially with the small diameter portion (7a) and having a smaller diameter than the small diameter portion (7a). The outer diameter of the end surface of the small diameter part (7a) of the rotor (7), that is, the outer diameter of the shoulder part (7b) between the small diameter part (7a) and the probe (8) It is preferable that the width is equal to or smaller than this width (see FIG. 2C). The rotor (7) and the probe (8) are made of a material that is harder than the materials to be joined (1) and (2) and has heat resistance that can withstand frictional heat generated during joining. The length of the probe (8) is preferably set to be equal to or greater than ½ of the thickness of both the joined materials (1) and (2).

  Then, while rotating the friction stir welding tool (6), the probe (8) was embedded in the weld metal part (3), and the shoulder (7b) of the rotor (7) was Press against the surface. Even if thinning occurs in the weld metal part (3) due to the influence of the shoulder part (7b) due to the pressing of the shoulder part (7b) against the surplus (5) surface, the thickness of the weld metal part (3) is It is possible to prevent the materials to be joined (1) and (2) from becoming thinner than the thickness. In addition, by pressing the shoulder (7b) against the surplus (5) surface, it is possible to prevent the fluffing of the softened portion that may occur at the start of stirring and during stirring to obtain a good stirring state. In addition, frictional heat is further generated by sliding between the weld metal part (3) and the shoulder part (7b) to promote softening of the contact part between the probe (8) and the weld metal part (3) and the vicinity thereof. It is possible to prevent the occurrence of irregularities such as burrs on the surface of the weld metal part (3).

  Next, the probe (8) is moved along the weld metal part (3) by relatively moving the workpieces (1), (2) and the friction stir welding tool (6) (FIG. 3). reference). Then, the frictional heat generated by the rotation of the probe (8) and the frictional heat generated by sliding between the weld metal part (3) and the shoulder part (7b) cause both the weld metal part (3) and the vicinity thereof to move. The metal that is the base material of the materials to be joined (1) and (2) is softened, and the softened portion is stirred and mixed by receiving the rotational force of the probe (8). After the plastic flow so as to fill, the phenomenon of rapidly losing frictional heat and solidifying by cooling is repeated with the movement of the probe (8), so that most of the weld metal part (3) and the vicinity thereof are covered. Joining material (1) (2) The base metal is friction stir mixed to form the friction stir zone (4), and welding defects such as blow holes, poor fusion and cracks in the friction stir zone (4) disappear. At the same time, the crystal grains become finer. Finally, surface finishing is performed, for example, by cutting, on the upper surface and the lower surplus (5) of the friction stirrer (4) so that the upper and lower surfaces of the materials to be joined (1) and (2) are smooth. Thus, a welded joint with improved fatigue characteristics is formed.

  In Embodiment 1 above, since the thickness of the materials to be joined (1) and (2) is 4 mm or more and the I-shaped groove, the molten metal part (3) is formed over the entire thickness of both materials to be joined (1) and (2). So that the welded materials (1) and (2) are melt welded from both sides. Even if it exists, a molten metal part can be formed over the full thickness of both to-be-joined materials (1) and (2) by melt-welding from one side.

  Next, a specific experimental example of the weld joint forming method of Embodiment 1 will be described together with a comparative experimental example.

Experimental example 1
Thickness made of rolled material of JIS A5083-H321: Prepare both bonded materials (1) and (2) of 4 mm, and the side edges of both bonded materials (1) and (2) become I-shaped grooves. The TIG welding was performed for each layer from both sides. At this time, a surplus (5) having a height of 1.0 mm was formed on both sides. The filler material is 2.3 mm in diameter made of JIS A5183BY, and the welding current is 190-200A on one side where welding is performed first, 170-190A on the other side where welding is performed later, welding speed is 100mm / min, the amount of argon gas was 12 l / min.

  Next, the diameter of the end surface of the small diameter portion (7a) in the rotor (7) (outer diameter of the shoulder portion (7b)): 16 mm, the diameter of the probe (8): 6 mm, and the length of the probe (8): 2 mm A friction stir welding tool (6) is prepared, and the weld metal of both workpieces (1) and (2) is prepared by the method described in Embodiment 1 under the conditions of a probe rotational speed of 1500 rpm and a probe moving speed of 200 mm / min. Part (3) was frictionally stirred from one side to form a welded joint. Finally, surface finishing by cutting was performed on the upper surface and the lower surplus (5) of the friction stirrer (4) so that the upper and lower surfaces of the materials to be joined (1) and (2) were smooth.

Experimental example 2
A welded joint was formed in the same manner as in Experimental Example 1 except that the length of the probe of the friction stir welding tool was 4 mm.

Comparative Experiment Example 1
In the same manner as in Experimental Example 1, TIG welding was performed on each material to be bonded from both sides. In addition, the friction stirring of the weld metal part was not performed. Thus, a weld joint was formed. Finally, surface finishing by cutting was performed on the upper and lower surpluses so that the upper and lower surfaces of the material to be joined were smooth.

Comparative Experiment Example 2
In the same manner as in Experimental Example 1, TIG welding was performed on each material to be bonded from both sides. Next, a friction stir welding tool having a diameter of the end face of the small diameter portion of the rotor of 16 mm and having no probe is prepared, and the rotor is rotated under the conditions of the rotor rotational speed: 1500 rpm and the moving speed: 200 mm / min. While rotating, the end surface of the small-diameter portion was linearly moved while being pressed against the surfacing surface of the weld metal portion from one side of both the joined materials. Thus, a weld joint was formed. Finally, surface finishing by cutting was performed on the upper and lower surpluses so that the upper and lower surfaces of the material to be joined were smooth.

  Five welded joints of Experimental Examples 1-2 and Comparative Experimental Examples 1-2 were prepared.

Evaluation test The plane bending fatigue test of the welded joint obtained in Experimental Examples 1-2 and Comparative Experimental Examples 1-2 was performed. The test conditions were a period: 60 Hz and a stress ratio: R = -1. As the fatigue strength, a value of 10 ⁷ repetitions was used, and the minimum value of five welded joints was used. The results are shown in Table 1.

As is apparent from Table 1, the fatigue strength of the welded joints of Experimental Examples 1 and 2 was greater than the fatigue strength of Comparative Experimental Examples 1 and 2. The fatigue strength of the base material of the material to be joined is 11 kgf / mm ² .

  Further, as a result of cross-sectional observation of the welded joints of Experimental Examples 1 and 2, the crystal grain size of the portion where the friction stirrer is not applied in the weld metal part (3) is 80 μm, and the part where the friction stirrer is applied The crystal grain size was 20 μm.

Embodiment 2
This embodiment is shown in FIGS. 4 and 5 and is a welded joint formed between two plate-like materials to be joined. In the description of the first embodiment, the upper and lower sides and the left and right sides in FIG.

  FIG. 4 shows a welded joint, and FIG. 5 shows a method for forming a welded joint.

  In FIG. 4, the welded joint has two aluminum plate-like materials to be joined (1) and (2) which are joined to each other at their side edges and melt welded from the upper surface side. (3) is friction stir from the upper surface side over a depth of 1/2 or more of the thickness of the materials to be joined (1) and (2) using the probe of the friction stir welding tool. The friction stirrer is indicated by (4). The depth of the friction stirrer (4) is 1/2 or more of the thickness of the materials to be joined (1) and (2).

  Next, a method for forming a welded joint will be described with reference to FIG.

  First, prepare two plate-like workpieces (1) and (2) with the same wall thickness, and machine the side edges of both of the workpieces (1) and (2). The side edges of 2) are arranged so as to form a U-shaped groove that opens upward (see FIG. 5A).

  The materials of both the joined materials (1) and (2) are the same as those in the first embodiment.

  Next, the two materials to be joined (1) and (2) are welded in two layers or two or more layers from above by an appropriate fusion welding method such as TIG or MIG (see FIG. 5 (b)). By melting and welding two or more layers of the materials to be bonded (1) and (2) with a U-shaped groove, the molten metal portion (3) is formed over the entire thickness of the materials to be bonded (1) and (2). At the time of this welding, a surplus (5) having a height of 1 mm or more is formed.

  Thereafter, in the same manner as in the first embodiment, the weld metal part (3) is friction-stirred from the upper surface side of both the workpieces (1) and (2) using the friction stir welding tool (6). Also in this case, the outer diameter of the end surface of the small-diameter portion (7a) of the rotor (7), that is, the outer diameter of the shoulder portion (7b) between the small-diameter portion (7a) and the probe (8) is extra (5 ) Is preferably equal to or smaller than the width in the left-right direction. Further, it is preferable that the length of the probe (8) is set to be ½ or more of the thickness of both the bonded materials (1) and (2). Finally, the upper part of the friction stirrer (4) and the melted part on the lower surface side of the weld metal part (3) are made, for example, by cutting, so that the upper and lower surfaces of the materials to be joined (1) and (2) are smooth. Apply surface finishing. Thus, a welded joint with improved fatigue characteristics is formed.

  The weld joints of Embodiments 1 and 2 are formed between adjacent members to be joined in a plate formed by welding a plurality of plate-like members to be joined. Such plates are used in various industries.

Embodiment 3
This embodiment is shown in FIGS. 6 and 7, and is a welded joint formed between two cylindrical members to be joined.

  FIG. 6 shows a welded joint, and FIG. 7 shows a method for forming a welded joint.

In FIG. 6, the welded joint has two aluminum cross-sections made of aluminum having the same thickness and outer diameter, and the end faces of the cylindrical joined materials (10) and (11) are butted together and melt welded from the outer surface side. The entire weld metal part was frictionally stirred from the outer surface side to a depth of 1/2 or more of the thickness of the materials to be joined (10) and (11) using the probe of the friction stir welding tool. The friction stirrer is indicated by (4). The depth in the radial direction of the friction stirrer (4) is equal to the thickness of the materials to be joined (10) (11). In addition, an annular support member (12) made of aluminum is disposed inside the both materials to be joined (10) and (11) so as to straddle both the materials to be joined (10) and (11), and this annular support member (12) Are welded to both of the workpieces (10) and (11). Next, a method for forming a welded joint will be described with reference to FIG.

  First, two cross-sectional cylindrical members to be joined (10) and (11) having the same thickness and outer diameter are prepared. Each of the tubular members (10) and (11) is formed by an appropriate method such as extrusion, forging, or cutting. Both cylindrical members to be joined (10) and (11) are made of any one of, for example, JIS A2000 alloy, JIS A5000 alloy, JIS A6000 alloy, and JIS A7000 alloy. Both the cylindrical members (10) and (11) may be formed of the same material, or may be formed of different materials.

  Next, the end faces of the two materials to be joined (10) and (11) are processed so that the joint ends of the materials to be joined (10) and (11) are arranged in U-shaped grooves that open outward. To do. At this time, the annular support member (12) is disposed on the inner side of the members to be joined (10) and (11) across the members to be joined (10) and (11) (see FIG. 7 (a)). The annular support member (12) is made of, for example, any one of JIS A2000 alloy, JIS A5000 alloy, JIS A6000 alloy, and JIS A7000 alloy.

  Subsequently, the two materials to be joined (10) and (11) are welded in two layers or two or more layers from the outer surface side by an appropriate fusion welding method such as TIG or MIG. By melt-welding two or more layers of the materials to be bonded (10) and (11) with a U-shaped groove, a molten metal portion (3) is formed over the entire thickness of the materials to be bonded (10) and (11) ( (See FIG. 7 (b)). At the time of this welding, a surplus (5) having a height of 1 mm or more is formed. Further, at the time of this welding, a part of the annular support member (12) is melt-welded to both the joined materials (10) and (11). Further, on both sides of the surplus (5), overlay welding is performed on the outer surfaces of both the joined materials (10) and (11), and the surfacing portion (13) having a height of 1 mm or more connected to the surplus (5) is formed. It is formed (see FIG. 7 (c)).

  Thereafter, in the same manner as in the first embodiment, the friction stir welding tool (6) is used to frictionally stir the weld metal part (3) from the outer surface side of both the workpieces (10) and (11). A stirring part (4) is formed. Here, the length of the probe (8) is set to be longer than the thickness of both the joined materials (10) and (11). Then, at the time of friction stirring, the annular support member (12) can be friction stir welded to both the workpieces (10) and (11) simultaneously with friction stirring of the molten metal portion (3). The length of the probe (8) is long, and the annular support member (12) is friction stir welded to both the workpieces (10) and (11), whereby the entire weld metal part (3) is friction stir. In this case, the outer diameter of the end surface of the small diameter portion (7a) of the rotor (7), that is, the outer diameter of the shoulder portion (7b) between the small diameter portion (7a) and the probe (8) It is preferable to make it equal to or smaller than the width in the length direction of the parts to be joined (10) and (11) in the combined portion of 5) and the two overlaid parts (13) (FIG. 7). (See (c)). In other words, in order to make the length of the probe (8) longer than the thickness of both the joined materials (10) and (11), it is necessary to increase the outer diameter of the shoulder (7b). If the portion (13) is formed, the shoulder portion (7b) is not directly pressed against the outer surface of the both bonded materials (10) and (11), and both the bonded materials (10) (11 ) Is prevented from thinning.

  Finally, surface finishing processing such as cutting is performed on the outer surface of the friction stirrer (4) and the outer surface of the build-up part (13) so that the outer surfaces of the materials to be joined (10) and (11) are smooth cylindrical surfaces. Apply. Thus, a welded joint with improved fatigue characteristics is formed.

  In Embodiment 3 described above, the annular support member (12) is not necessarily required to be friction stir welded to the materials to be joined (10) and (11). In this case, the length of the probe (8) of the friction stir welding tool (6) is not less than 1/2 of the thickness of the materials to be joined (10) and (11) as in the first embodiment. Good. Further, since the probe (8) is shortened, it is not necessary to increase the outer diameter of the shoulder portion (7b), and the rotor (7 ), The outer diameter of the end surface of the small diameter portion (7a), that is, the outer diameter of the shoulder portion (7b) between the small diameter portion (7a) and the probe (8), ) (11) can be made equal to or smaller than the width in the length direction. Furthermore, when the annular support member (12) is not friction stir welded to both the workpieces (10) and (11), the annular support member (12) made of a material other than aluminum can be used.

Embodiment 4
This embodiment is shown in FIG. 8, and is a welded joint formed between two cylindrical members to be joined.

  As shown in FIG. 8, the difference between the welded joint of the fourth embodiment and the welded joint of the third embodiment is that no annular support member is arranged on the inner side of both the joined materials (10) and (11). . Therefore, the weld metal portion (3) remains even after the friction stir zone (4) is formed.

  The weld joint forming method shown in FIG. 8 is that the annular support member is not disposed, the length of the probe (8) of the friction stir welding tool (6) is set to the thickness of the workpieces (10) and (11). Of the end of the small diameter part (7a) of the rotor (7), that is, the small diameter part (7a) and the probe (8 ) Between the outer diameter of the shoulder (7b) between the two parts (10) and (11) in the extrascore (5) is equal to or smaller than the width in the longitudinal direction. Except for this, the method is the same as the method of forming the welded joint of the third embodiment.

  In the said Embodiment 3 and 4, although a cylindrical to-be-joined material is a cross-sectional circle, it is not limited to this, For example, a cross-section ellipse may be sufficient.

  The welded joints of the third and fourth embodiments are formed between adjacent pipe constituent members in a pipe formed by welding a plurality of metal tubular pipe constituent members, for example. Such pipes are used in various industries to distribute gas or liquid inside. An example of the gas is hydrogen gas.

  In addition, the welded joints of Embodiments 3 and 4 include, for example, a cylindrical body and a closing plate that closes at least one end opening of the body, and at least 2 formed into a shape that is divided in the length direction of the body. In a container formed by welding two metal container constituent members, when each container constituent member has a cylindrical peripheral wall portion, it is formed between the peripheral wall portions of adjacent container constituent members. The Such containers are used in various industries to fill a gas or liquid inside.

It is an expanded sectional view showing Embodiment 1 of the weld joint by this invention. It is an expanded sectional view which shows the method of forming the welded joint shown in FIG. It is an expansion perspective view which shows the method of forming the welded joint shown in FIG. It is an expanded sectional view which shows Embodiment 2 of the welded joint by this invention. It is an expanded sectional view which shows the method of forming the welded joint shown in FIG. It is an expanded sectional view which shows Embodiment 3 of the welded joint by this invention. It is an expanded sectional view which shows the method of forming the welded joint shown in FIG. 1 is a partially cutaway perspective view showing an embodiment of a welded joint according to the present invention.

Explanation of symbols

(1) (2): Material to be joined
(3): Weld metal part
(4): Friction stirrer
(5): Additional
(6): Friction stir welding tool
(7): Rotor
(7b): Shoulder
(8): Probe
(10) (11): Material to be joined
(12): Annular support member

Claims (20)

A welded joint in which a weld metal portion formed by melting and welding two metal workpieces is friction stir using a probe of a friction stir welding tool. The welded joint according to claim 1, wherein the two materials to be joined are made of aluminum. The welded joint according to claim 1 or 2, wherein a part of the weld metal part having a thickness of 1/2 or more of the thickness of the material to be joined is frictionally stirred. After welding two metal workpieces by fusion welding, the weld metal parts of both workpieces are embedded while rotating the probe of the friction stir welding tool, and both probes are rotated while rotating the probe. A method for forming a welded joint, characterized in that a weld metal part of both materials to be joined is frictionally stirred by relatively moving a joining material and a friction stir welding tool. The method for forming a welded joint according to claim 4, wherein the two materials to be joined are made of aluminum. During welding by the fusion welding method, a surplus with a height of 1 mm or more is formed, and the shoulder of the rotor of the friction stir welding tool is pressed against the surplus during friction stir of the welded metal parts of both workpieces The method for forming a welded joint according to claim 4 or 5. The method for forming a welded joint according to any one of claims 4 to 6, wherein the length of the probe of the friction stir welding tool is set to ½ or more of the thickness of the material to be joined. The two materials to be joined are plate-shaped, both the materials to be joined are melt-welded from both sides, and the molten metal part is frictionally stirred from one side of both the materials to be joined. A method for forming a welded joint. The two materials to be joined are plate-like, both the materials to be joined are melt-welded from one side, and the molten metal portion is friction-stirred from one side where melt-welding is performed on both the materials to be joined. The formation method of the weld joint in any one. The method for forming a welded joint according to any one of claims 4 to 7, wherein the two materials to be joined are cylindrical. The method for forming a welded joint according to claim 10, wherein an annular support member made of metal is disposed inside the two materials to be joined so as to straddle both the materials to be joined. The method for forming a welded joint according to claim 11, wherein the annular support member is friction stir welded to both of the welded materials at the time of friction stirring of the weld metal portions of the both welded materials. It forms by welding several metal plate-shaped to-be-joined materials, The welded joint in any one of Claims 1-3 is formed between adjacent to-be-joined materials. Board. A plurality of metal tubular pipe constituent members are formed by welding, and a welded joint according to any one of claims 1 to 3 is formed between adjacent pipe constituent members. Piping. The piping according to claim 14, wherein a gas or a liquid is circulated therein. The piping according to claim 15, wherein the gas is hydrogen gas. It is formed by welding at least two metal container constituent members that are formed of a cylindrical body and a closing plate that closes at least one end opening of the body and that are divided in the length direction of the body. Each of the container constituent members has a cylindrical peripheral wall portion, and the welded joint according to any one of claims 1 to 3 is formed between the peripheral wall portions of adjacent container constituent members. Container. The container of Claim 17 by which the metal cyclic | annular support member is arrange | positioned so that it may straddle the surrounding wall part of both the container structural members inside the surrounding wall part of an adjacent container structural member. The container according to claim 18, wherein the support member is friction stir welded to the peripheral wall portions of both container constituent members. The container in any one of Claims 17-19 with which a gas or a liquid is filled inside.

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