JP2013082007A - Method for manufacturing tool for friction stir welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a tool for friction stir welding with which a high-melting-point member can be subjected to friction stir welding, and to provide a tool for friction stir welding.SOLUTION: The method manufactures the tool 3 for friction stir welding, in which the tool for friction stir welding formed of an iridium-based alloy includes a cylindrical shank 5, a shoulder 9 formed at an end of the shank and a pin 4 formed at an end of the shoulder. The method includes: a step 1 of forming an ingot 10 formed of the iridium-based alloy; a step 3 of forming a cylindrical body 20 for a tool from the ingot; and a step 4 of forming the shoulder and the pin by machining the cylindrical body for a tool.

Description

  The present invention relates to a method for manufacturing a friction stir welding tool for friction stir welding of high melting point members.

  As a metal joining method, a technique of a friction stir welding method is disclosed (for example, refer to Patent Document 1 or 2). As for the friction stir welding method, many studies have been made on aluminum or aluminum alloys having a relatively low melting point, and the friction stir welding method is applied using a metal or alloy having a high melting point of 1350 ° C. or higher as a member to be joined. There have been few reports. However, the present applicant has proposed a friction stir welding method for platinum or a platinum-based alloy having a high melting point (see, for example, Patent Document 3). Further, a friction stir welding tool capable of friction stir welding of a high melting point member such as platinum, a platinum base alloy, or stainless steel has been proposed (see, for example, Patent Document 4 or 5).

JP 7-505090 Gazette Japanese National Patent Publication No. 9-508073 Japanese Patent Laid-Open No. 2004-090050 JP 2006-320958 A Japanese Patent No. 4047371

  Friction stir welding tools for friction stir welding of high melting point materials such as platinum or platinum-based alloys or stainless steel are resistant to chemical stability, heat resistance, wear resistance and heat resistance even when heated to high temperatures by friction. It is necessary to form with the material which has impact property. On the other hand, these materials are difficult to process, and no specific method for manufacturing a tool suitable for friction stir welding has been disclosed so far.

  An object of the present invention is to provide a method for manufacturing a friction stir welding tool capable of friction stir welding high melting point members.

  A method of manufacturing a friction stir welding tool according to the present invention includes a cylindrical shank portion, a shoulder portion formed at an end portion of the shank portion, and a pin portion formed at an end portion of the shoulder portion. In the method of manufacturing a friction stir welding tool made of an iridium-based alloy, a step 1 of forming an ingot made of an iridium-based alloy, a step 3 of forming a tool cylinder from the ingot, and processing the tool cylinder And the step 4 of forming the shoulder portion and the pin portion.

  In the method for manufacturing a friction stir welding tool according to the present invention, the pin portion is preferably formed by at least one of grinding, electric discharge, cutting, laser processing, and water jet processing. The surface of the pin portion can be processed to a roughness suitable for friction stir welding.

  In the method for manufacturing a friction stir welding tool according to the present invention, it is preferable to further include a step 2 of plastically processing the ingot between the step 1 and the step 3. Furthermore, a tool having high hardness and high strength at high temperature can be obtained.

  In the method for manufacturing a friction stir welding tool according to the present invention, the step 4 may be performed by using at least one machining method of electric discharge machining, grinding machining, cutting machining, or laser machining to share a main shaft with the tool cylinder. And forming a tip cylinder having a diameter smaller than the diameter of the tool cylinder on one end face side of the tool cylinder, the process 4A comprising: A roughing process is preferred. A tool can be manufactured efficiently.

  In the method for manufacturing a friction stir welding tool according to the present invention, after the step 4A, the shoulder portion and the above-described method are performed by at least one of electric discharge machining, grinding, cutting, laser machining, and water jet machining. It is preferable to have a pin finishing step 4B for finishing the shoulder portion and the pin portion without providing a groove having a depth of 0.1 mm or more in the pin portion. A grooveless type tool can be manufactured with high accuracy.

  In the friction stir welding tool manufacturing method according to the present invention, after the step 4A, the shoulder portion and the pin portion are deepened by at least one of electric discharge machining, grinding, cutting, or laser machining. It is preferable to have a pin finishing step 4C in which a groove of 0.1 mm or more is provided to finish the shoulder portion and the pin portion. A grooved type tool can be manufactured with high accuracy.

  The present invention can provide a method for manufacturing a friction stir welding tool capable of friction stir welding high melting point members.

It is the schematic which shows one form of the mechanism of a friction stir welding method. FIG. 5 is a schematic diagram for explaining step 1; FIG. 6 is a schematic diagram for explaining step 3; It is the schematic for demonstrating process 4A. It is a front view which shows the example of a 1st form of a pin part. It is a front view which shows the 2nd example of a pin part. It is a front view which shows the 3rd example of a pin part. It is a figure for demonstrating the formation process of a fixing | fixed part, and is a front view which shows the state which formed the fixing | fixed part in the outer periphery of the cylindrical body for tools which has a pin part shown in FIG.

  Next, although an embodiment is shown and explained in detail about the present invention, the present invention is limited to these descriptions and is not interpreted. As long as the effect of the present invention is exhibited, the embodiment may be variously modified.

  FIG. 1 is a schematic view showing an embodiment of the mechanism of the friction stir welding method. FIG. 2 is a schematic diagram for explaining the step 1. FIG. 3 is a schematic diagram for explaining the step 3. FIG. 4 is a schematic diagram for explaining the step 4A. FIG. 5 is a front view showing a first embodiment of the pin portion. FIG. 6 is a front view showing a second embodiment of the pin portion. FIG. 7 is a front view showing a third embodiment of the pin portion. As shown in FIG. 1, the method of manufacturing the friction stir welding tool 3 according to the present embodiment includes a columnar shank portion 5, a shoulder portion 9 formed at the end of the shank portion 5, and the shoulder portion 9. In the friction stir welding tool made of an iridium-based alloy including the pin portion 4 formed at the end, as shown in FIG. 2, a step 1 for forming an ingot 10 made of an iridium-based alloy, as shown in FIG. Step 3 for forming the tool cylinder 20 from the ingot 10 and Step 4 for processing the tool cylinder 20 as shown in FIGS. 4 to 7 to form the shoulder portion 9 and the pin portion 4. Have.

  Next, each step will be described in order.

(Process 1)
The manufacturing method of the friction stir welding tool 3 according to the present embodiment includes a step of forming an ingot 10 made of an iridium-based alloy as step 1 as shown in FIG. The ingot 10 is preferably formed by, for example, blending Ir and a metal species other than Ir at a predetermined mass ratio and dissolving them. Examples of the melting method include arc melting, high frequency melting, plasma melting, and vacuum melting. The shape of the ingot 10 is, for example, an elliptical columnar shape or a prismatic shape other than the columnar shape shown in FIG.

(Process 2)
The method for manufacturing the friction stir welding tool 3 according to the present embodiment preferably includes a step of plastic working the ingot 10 as the step 2 between the step 1 described above and the step 3 described later. The purpose of plastic working is to eliminate melting defects, refine crystal grains, homogenize crystal grains, and improve mechanical properties. The plastic working is, for example, hot forging or hot rolling. When the plastic working is hot rolling, the ingot is heated and then rolled. The heating temperature varies depending on the material, but it is preferably performed at a temperature equal to or higher than the recrystallization temperature of the iridium-based alloy forming the ingot. Here, the recrystallization temperature refers to a temperature at which the internal deformation of the metal material generated by the plastic processing is removed and the metal material becomes soft when the metal material is plastic processed and then heated again. In the hot rolling, heating can be performed, for example, in an air atmosphere or an argon atmosphere, but is more preferably performed in an argon atmosphere.

(Process 3)
The method for manufacturing the friction stir welding tool 3 according to the present embodiment includes a step of forming the tool cylinder 20 from the ingot 10 as step 3.

  In step 3, the tool cylinder 20 is cut out from the ingot 10 as shown in FIG. The cutting of the tool cylinder 20 is preferably performed by any one of electric discharge machining such as wire electric discharge machining, laser cutting machining, or water jet cutting machining. These processing methods may be applied singly or in combination of two or more.

(Shank finishing process)
A part of the tool cylinder 20 cut out in the step 3 may be used as the shank part 5 as it is, but in the present embodiment, the shank part 5 is formed through a process of further finishing the outer periphery of the tool cylinder 20. It is more preferable. By performing the finishing process of the shank part 5, the roundness accuracy of the outer periphery of the shank part 5 can be improved, and the tool 3 with smaller runout can be obtained. The finishing process of the shank portion 5 is preferably formed by at least one processing method of grinding, electric discharge processing, cutting processing, laser processing, or water jet processing. These processing methods may be applied singly or in combination of two or more. Among these, grinding and cutting are more preferable. In addition, when performing the finishing process of the shank part 5, processing of the shoulder part 9 and the pin part 4 in the next process 4 to be performed without removing the tool cylinder 20 attached to the jig is a series of processes. It is preferable to carry out with. The main axes of the shank part 5, the shoulder part 9 and the pin part 4 can be made coaxial, and the tool 3 with even smaller runout can be obtained. Moreover, when performing the finishing process of the shank part 5, the finishing process of the shank part 5, the process of the shoulder part 9 in the process 4, and the process of the pin part 4 employ | adopt the same processing method from a viewpoint of work efficiency. It is more preferable.

(Process 4)
The method for manufacturing the friction stir welding tool 3 according to the present embodiment includes a step of processing the tool cylinder 20 to form the shoulder portion 9 and the pin portion 4 as step 4.

  The shoulder portion 9 is preferably formed by at least one processing method of grinding processing, electric discharge processing, cutting processing, laser processing, or water jet processing. These processing methods may be applied singly or in combination of two or more. Among these, grinding and cutting are more preferable.

  The pin portion 4 is preferably formed by at least one processing method of grinding, electric discharge processing, cutting processing, laser processing, or water jet processing. These processing methods may be applied singly or in combination of two or more. Among these, grinding and cutting are more preferable.

  The processing of the shoulder portion 9 and the processing of the pin portion 4 are preferably performed in a series of steps without removing the tool column 20 while it is attached to the jig. Working efficiency can be improved by processing in a series of steps without removing from the jig. Moreover, the main axis O of the shoulder part 9 and the pin part 4 can be formed coaxially, and the tool 3 with smaller runout can be obtained. Further, it is more preferable to adopt the same processing method for processing of the shoulder portion 9 and processing of the pin portion 4 from the viewpoint of work efficiency.

(Step 4A)
In the method for manufacturing the friction stir welding tool 3 according to the present embodiment, the step 4 preferably includes a rough machining step of the pin portion 4 as the step 4A. As shown in FIG. 4, the rough machining process of the pin portion 4 has a common spindle O with the tool cylinder 20 by at least one of electric discharge machining, grinding machining, cutting machining, or laser machining. And it is the process of forming the front-end | tip part cylindrical body 23 which has the diameter D2 smaller than the diameter D1 of the cylindrical body 20 for tools on the one end surface side of the cylindrical body 20 for tools. By having this process 4A, the tool 3 can be manufactured efficiently. For the roughing process of the pin portion 4, only one of electric discharge machining, grinding, cutting, or laser processing may be applied, or two or more may be applied in combination. Among these, grinding and cutting are more preferable.

  The tip cylindrical body 23 formed in the step 4A may be used as the pin portion 4 as it is, but in the present embodiment, it is more preferably formed through the pin finishing process 4B or the pin finishing process 4C. The pin finishing process 4B or the pin finishing process 4C is performed in accordance with the shape of the pin part 4.

(Pin finishing process 4B)
In the method for manufacturing a friction stir welding tool according to the present embodiment, as shown in FIG. 5, after step 4A, at least one of electric discharge machining, grinding, cutting, laser machining, and water jet machining is used. It is preferable to have a pin finishing step 4B for finishing the shoulder portion 9 and the pin portion 4 without providing a groove having a depth of 0.1 mm or more in the shoulder portion 9 and the pin portion 4. By having this pin finishing step 4B, the tool 3 can be manufactured with high accuracy. In the pin finishing step 4B, only one of the above-described processing methods may be applied, or two or more may be applied in combination. Among these, grinding and cutting are more preferable.

(Pin finishing process 4C)
In the method for manufacturing a friction stir welding tool according to the present embodiment, as shown in FIG. 6 or FIG. 7, after step 4 </ b> A, at least one of electric discharge machining, grinding, cutting, or laser machining is used. It is preferable to have a pin finishing step 4C in which grooves 21 (21a, 21b) having a depth of 0.1 mm or more are provided in the shoulder portion 9 and the pin portion 4 to finish the shoulder portion 9 and the pin portion 4. The groove 21 is, for example, an annular groove 21a as shown in FIG. 6 or a screw 21b as shown in FIG. Here, the shape of the screw 21b includes a multi-stepped step. By having this pin finishing step 4C, the tool 3 can be manufactured with high accuracy. In the pin finishing step 4C, only one of the above-described processing methods may be applied, or two or more may be applied in combination. Among these, grinding and cutting are more preferable.

(Fixing part forming process)
FIG. 8 is a view for explaining a fixing portion forming process, and is a front view showing a state in which the fixing portion is formed on the outer periphery of the tool cylinder having the pin portion shown in FIG. 5. In the manufacturing method of the stir welding tool 3 according to the present embodiment, as shown in FIG. 8, the outer periphery of the tool cylinder 20 is processed, and the tool 3 is used as a friction stir welding apparatus in a part of the shank portion 5. It is preferable to have the process of forming the fixing | fixed part 22 for attachment. More preferably, the forming step of the fixing portion 22 is performed after the step 4. By performing the step of forming the fixing portion 22 after the step 4, the shank portion 5, the shoulder portion 9 and the pin portion 4 can be processed in a series of steps without removing the tool cylinder 20 from the jig. The tool 3 with higher accuracy can be obtained. Moreover, since the fixing | fixed part 22 can be formed corresponding to the main axis | shaft of the tool 3, the runout at the time of joining can be made smaller. The fixing portion 22 is preferably formed by any one processing method of electric discharge machining such as grinding, cutting, or wire electric discharge machining. These processing methods may be applied singly or in combination of two or more. Among these, electric discharge machining and grinding are more preferable.

  Next, the friction stir welding tool 3 according to this embodiment will be described. The friction stir welding tool 3 according to this embodiment includes a cylindrical shank portion 5, a shoulder portion 9 formed at an end of the shank portion 5, and a shoulder as shown in FIG. 5, FIG. 6, or FIG. 7. It is a friction stir welding tool made of an iridium-based alloy including a pin portion 4 formed at the end of the portion 9.

  The friction stir welding tool 3 according to the present embodiment has a Vickers hardness of 200 Hv or more measured according to JIS Z 2244: 2009 “Vickers hardness test-test method” at least in a portion contacting the members 1A and 1B to be joined. It is preferable. More preferably, it is 300 Hv or more. The upper limit of Vickers hardness is preferably 1200 Hv from the viewpoint of workability. The upper limit is more preferably 1100 Hv. The Vickers hardness is measured using, for example, a Vickers hardness tester (HV-112 manufactured by Mitutoyo Corporation).

  Next, the process of the friction stir welding method will be described with reference to FIG. 1 again.

  In the friction stir welding method, the members 1A and 1B are brought into contact with each other or substantially in contact with each other to define the elongated joining region 2, and the friction stir welding tool 3 is inserted into the joining region 2 while rotating. And a step of generating frictional heat between the friction stir welding tool 3 and the bonding region 2 and generating a plastic region in the generated bonding region to bond the members to be bonded 1A and 1B together.

  First, the joined members 1A and 1B are substantially brought into contact with each other on the condition that they are brought into contact with each other or subjected to friction. Further, the joining region 2 is elongated, and continuous joining is performed instead of spot joining. Thereby, the high melting point member can be friction stir welded. The members 1A and 1B to be joined include, for example, metals or alloys having a high melting point of 1600 ° C. or higher. Examples of the metal or alloy having a high melting point of 1600 ° C. or more include titanium, titanium-based alloy, platinum, platinum-based alloy, or oxide in which oxide fine particles such as zirconium oxide, aluminum oxide, yttrium oxide, and hafnium oxide are dispersed. It is a dispersion strengthened metal or an alloy thereof. In the present embodiment, the members to be joined 1A and 1B naturally include metals or alloys having a melting point of less than 1600 ° C. Examples of the metal or alloy having a melting point of less than 1600 ° C. are stainless steel or steel having a carbon content of 2% by mass or less. The members 1A and 1B to be joined may be made of the same material or different materials. Moreover, the back plate 6 is arrange | positioned at the back surface side of to-be-joined member 1A, 1B.

  Next, the friction stir welding tool 3 is rotated, and the pin portion 4 is slowly inserted into the coupling region 2. At this time, the shoulder portion 9 is in contact with the surfaces of the members 1A and 1B to be joined. The friction stir welding tool 3 is attached to the motor 7 of the apparatus by a fixing part (not shown) formed in a part of the shank part 5 and is rotated by the motor 7. When the friction stir welding tool 3 rotates while the pin portion 4 is inserted into the coupling region 2, the material at the contact point is rapidly heated by friction, and as a result, the mechanical strength of the material decreases. The friction stir welding tool 3 moves along the advancing direction 8 while kneading and extruding the material. In the coupling region 2, the frictional heat generated by rotating the pin portion 4 and the shoulder portion 9 in contact with each other forms a high-temperature plastic region in the metal around the pin portion 4 and the shoulder portion 9. When the members 1A and 1B are moved in the direction opposite to the movement of the friction stir welding tool 3 or vice versa, the plasticized metal is crushed at the front end of the friction stir welding tool 3 in the advancing direction 8 and mechanically stirred. And it moves to a rear end by the forging action by the shape and rotation direction of the tool 3 for friction stir welding. As a result, the joint portion on the front surface of the friction stir welding tool 3 is heated to create a plastic region. Then, the plastic region is cooled at the rear end of the friction stir welding tool 3 while stirring the crushed metal that breaks the oxide film present on the members 1A and 1B to form a solid weld. All of this phenomenon occurs at a temperature lower than the melting point of the members to be joined 1A, 1B.

  In the friction stir welding method, cracks are eliminated, there is no loss of alloy elements due to evaporation of the weld metal, the alloy components can be held as they are, and a fine granular structure is formed in the weld metal by press-fitting, stirring and forging action of the welding tool. There is a merit that

1A, 1B Joined member 2 Joining region 3 Friction stir welding tool 4 Pin part 5 Shank part 6 Back plate 7 Motor 8 Friction stir welding tool traveling direction 9 Shoulder part 10 Ingot 20 Tool cylinder 21 Groove 21a Annular groove 21b Screw 22 Fixing part 23 Tip cylindrical body

Claims (6)

A method for manufacturing a friction stir welding tool made of an iridium-based alloy, comprising: a cylindrical shank portion; a shoulder portion formed at an end portion of the shank portion; and a pin portion formed at an end portion of the shoulder portion. In
Step 1 of forming an ingot made of an iridium-based alloy;
Forming a tool cylinder from the ingot; and
And a step 4 of forming the shoulder portion and the pin portion by processing the cylindrical body for the tool, and a method for producing a friction stir welding tool.   2. The method of manufacturing a friction stir welding tool according to claim 1, wherein the pin portion is formed by at least one of grinding, electric discharge machining, cutting, laser machining, and water jet machining. .   The method for manufacturing a friction stir welding tool according to claim 1 or 2, further comprising a step 2 of plastically processing the ingot between the step 1 and the step 3.   The step 4 has a spindle common to the tool cylinder and at least one end surface of the tool cylinder by at least one of electric discharge machining, grinding, cutting, or laser machining. The method includes a step 4A of forming a tip end cylindrical body having a diameter smaller than the diameter of the tool cylindrical body on the side, wherein the step 4A is a rough machining step of the pin portion. 4. A method for producing a friction stir welding tool according to any one of 3 above.   After the step 4A, the shoulder portion and the pin portion are not provided with a groove having a depth of 0.1 mm or more by at least one processing method of electric discharge machining, grinding, cutting, laser processing, or water jet processing. 5. The method of manufacturing a friction stir welding tool according to claim 4, further comprising a pin finishing step 4B for finishing the shoulder portion and the pin portion.   After the step 4A, a groove having a depth of 0.1 mm or more is provided in the shoulder portion and the pin portion by at least one processing method of electric discharge machining, grinding processing, cutting processing, or laser processing, and the shoulder portion And a method of manufacturing a friction stir welding tool according to claim 4, further comprising a pin finishing step 4C for finishing the pin portion.

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