JP5441028B2 - Rotation tool - Google Patents

Description

  The present invention relates to a rotary tool, and in particular, a metal material treatment for rotating the rotary tool and bringing a tip portion thereof into contact with a stirring portion of the metal material to perform any one of the joining of the metal material and the surface modification. The present invention relates to a rotary tool (rotary tool) used in the method.

  Friction stir welding is a joining method in which a rod-shaped tool called a rotary tool is brought into contact with a metal member while rotating at high speed, and is joined using frictional heat with the metal member. The rotary tool is composed of a shoulder with a large diameter and a probe at its tip. During the joining, only the probe is pushed into the metal member and moved along the abutting surface to be joined. Join metal members. The shoulder serves both as an action for suppressing the metal member from being discharged to the outside by rotating while the probe enters the metal member, and as a heat source by friction with the surface of the metal member. This method can also be used for surface modification of materials, in which case a probe is not essential. Further, a probe is not necessary in the case of joining thin plates.

  For example, when joining an aluminum alloy, it is common to use SK such as SKD61 or SKD tool steel for the rotary tool. However, when joining carbon steel, which is a higher melting point material than aluminum, the softening temperature of carbon steel is as high as 700 ° C. to 1200 ° C., so it is necessary to use a high-rigidity rotary tool with excellent heat resistance and wear resistance. is there.

  Currently, in rotary tools for friction stir welding, cemented carbide is cited as a material for rotary tools applicable to carbon steel. For example, the rotary tool shown in Patent Document 1 is made of a WC-Co based cemented carbide and is used for friction stir welding of aluminum alloys and low carbon steels. In Patent Document 2, WC-Co cemented carbide is applied as a rotating tool for friction stir processing. The thing of patent document 2 is a tool used for surface modification of steel materials. Since the thing of patent document 2 aims at modification | reformation of a surface layer, the one where a tool load is smaller is good. Therefore, the thing of patent document 2 differs in the shape of the tool front-end | tip from the rotary tool for joining.

JP 2005-199281 A JP 2008-132524 A

  However, in the rotating tool of Patent Document 1, the rotating tool is easily broken when the material to be joined is difficult to join, such as high carbon steel, Ti alloy, high nitrogen steel, or heat-resistant steel. The current situation is that a long tool life is not obtained. In addition, since the rotary tool of Patent Document 2 has a tool tip shape different from that of the rotating tool for welding, the tool life is somewhat improved, but it does not lead to a significant improvement. Further, when this cemented carbide material is used to finish the shape of a rotating tool for joining and used for friction stir welding, the rotating tool is inevitably broken, and improvement is strongly desired. It is rare.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a rotating tool having a longer life even for metal materials that are difficult to be bonded or surface-modified. .

  The present invention relates to a rotation method used for a metal material processing method in which a tip of a rotary tool is brought into contact with a stirring portion of a metal material while rotating a rod-shaped rotary tool, and either metal material joining or surface modification is performed. It is a tool, Comprising: At least the front-end | tip part of a rotary tool consists of a composition containing WC, Ni, and Cr, and is a rotary tool in which the Rockwell hardness exists in the range of HRA = 85-95.

  According to this configuration, in the method of treating a metal material, the tip of the rotary tool is brought into contact with the stirring portion of the metal material while rotating the rod-shaped rotary tool, and the metal material is bonded or surface-modified. In the rotary tool to be used, at least the tip portion of the rotary tool is made of a composition containing WC, Ni and Cr, and the Rockwell hardness is in the range of HRA = 85 to 95. The present inventors have found that the above problem can be solved by using Ni for the metal phase in the material composition of the rotary tool. The high-temperature stable phase of iron is austenite, the crystal structure is body-centered cubic, and the crystal structure of Ni is the same. For this reason, the Ni metal phase is excellent in high temperature strength. Furthermore, in the Ni—Cr phase in which Cr is solid-dissolved, the strength is improved by solid solution strengthening and the characteristics are excellent in thermal stress, oxidation resistance, and corrosion resistance. As a result, in the WC—Ni—Cr alloy, the welding resistance is greatly improved as compared with the WC—Co alloy. For this reason, the frictional resistance generated during friction stir welding is stabilized, so stress concentration due to (friction resistance + bending stress) associated with an unexpected increase in frictional resistance during welding can be avoided, and tool breakage can be prevented. it can. In addition, according to the above configuration, since at least the tip of the rotary tool has a Rockwell hardness in the range of HRA = 85 to 95, it is longer even for metal materials that are difficult to bond or modify the surface. It can have a lifetime.

  In addition, in the processing method of the metal material in this invention, (1) The edge parts of plate-shaped metal material are faced | matched and it is set as a junction part, It is moved while rotating a rotary tool along the longitudinal direction of the junction part. Friction stir welding that joins metal materials, (2) Spot friction stir welding where the ends of plate-shaped metal materials are butted together to form a joint, and the rotary tool is rotated without moving at the joint ( (Spot FSW), (3) Spot friction stir welding where metal materials are overlapped at the joint, a rotating tool is brought into contact with the joint, and the rotating tool is rotated without moving at that location to join the metal materials together. (4) Friction stir welding in which metal materials are overlapped at a joint, a rotary tool is brought into contact with the joint, and the rotary tool is moved while rotating along the longitudinal direction of the joint to join the metal materials together. Includes four aspects and combinations of these (1) to (4). Further, the metal material processing method of the present invention includes a mode in which the surface of the metal material is modified by bringing the rotary tool into contact with the surface of the metal material while rotating. Furthermore, it does not matter whether the metal material to be treated is the same material or a different material.

  In this case, it is preferable that at least the tip of the rotary tool has a composition in which Ni is 2 to 15% by weight and Cr is 0.3 to 3% by weight.

  According to this configuration, the composition is such that Ni is in the range of 2 to 15% by weight and Cr is in the range of 0.3 to 3% by weight, and the Ni—Cr phase has a composition ratio compared to WC which is the main component of the rotary tool. 18% by weight or less. As described above, when the Ni content is 2% by weight or more, the material of the rotary tool can be strengthened, and when the Ni content is 15% by weight or less, a decrease in strength can be prevented. Further, when Cr is 0.3% by weight or more, oxidation resistance is improved, and when it is 3% by weight or less, strength reduction can be prevented. Furthermore, by setting the Ni—Cr phase to a composition ratio of 18% by weight or less in this way, the distance between WC particles can be narrowed and deformation of the rotating tool at high temperatures can be suppressed.

  Moreover, it is preferable that at least the tip portion of the rotary tool is made of a composition further containing Co.

  According to this configuration, at least the tip portion of the rotary tool is made of a composition further containing Co. Co-Ni-Cr in which Co is added to Ni-Cr has a tougher metal phase and has a sufficient and sufficient proof strength against the frictional resistance and bending stress between the rotating tool and the metal material generated during friction stir welding. And can. In addition, with Co—Ni—Cr, the thermal crack resistance can be improved.

  In this case, it is preferable that at least the tip portion of the rotary tool has a composition in the range of 3 to 12% by weight of Co, 1 to 6% by weight of Ni, and 0.2 to 2% by weight of Cr.

  According to this configuration, the composition is in the range of 3 to 12% by weight of Co, 1 to 6% by weight of Ni and 0.2 to 2% by weight of Cr, and the Co—Ni—Cr phase is the main component of the rotary tool. The composition ratio is 18% by weight or less as compared with WC. Thus, like the WC-Ni-Cr composition described above, the oxidation resistance is improved by setting Co to 3% by weight or more, and the strength can be prevented from decreasing by setting it to 12% by weight or less. . Furthermore, by setting the Co—Ni—Cr phase to a composition ratio of 18% by weight or less in this way, the distance between WC particles can be narrowed, and deformation of the rotating tool at high temperatures can be suppressed.

  Moreover, it is preferable that the average particle size of WC is in the range of 0.2 to 2.5 μm.

  According to this configuration, the average particle size of WC is in the range of 0.2 to 2.5 μm. When the thickness is 0.2 μm or more, the material becomes extremely strong, and when the thickness is 2.5 μm or less, a decrease in strength can be prevented. Thus, by reducing the size of the WC particles as much as possible and reducing the distance between the WC particles, deformation of the rotating tool at high temperatures can be suppressed.

  On the other hand, the present invention provides a method for treating a metal material in which the tip of the rotary tool is brought into contact with the stirring portion of the metal material while rotating the rod-shaped rotary tool, and the metal material is bonded or surface-modified. It is a rotary tool used, Comprising: At least the front-end | tip part of a rotary tool consists of a composition containing TiC, Mo, Ni, and Cr, and is a rotary tool whose Rockwell hardness exists in the range of HRA = 85-95.

  According to this configuration, in the method of treating a metal material, the tip of the rotary tool is brought into contact with the stirring portion of the metal material while rotating the rod-shaped rotary tool, and the metal material is bonded or surface-modified. In the rotary tool to be used, at least the tip portion of the rotary tool is made of a composition containing TiC, Mo, Ni and Cr, and the Rockwell hardness is in the range of HRA = 85 to 95. Thus, even if the WC phase is replaced with the TiC-Mo phase, the same effect as the rotary tool of the above-described WC-Ni-Cr alloy or WC-Co-Ni-Cr alloy as a rotary tool for friction stir welding is obtained. Is obtained. However, the addition of Mo in this case is for the purpose of improving wettability of the TiC phase and suppressing particle growth, and Mo is for forming TiC and hard particles. Furthermore, WC is very expensive as a rare metal, and in recent years, the need for recycling is also increasing as a national policy. Therefore, the ability to replace WC with TiC ensures stable supply in terms of resources. Moreover, TiC is excellent in hardness compared with WC. Incidentally, while WC is HV = 1800, TiC is about HV = 3200. Because of this characteristic difference, the amount of wear of the tool is reduced, so that the tool life can be extended.

  In this case, it is preferable that at least the tip of the rotary tool has a composition in which Mo is 15 to 30% by weight, Ni is 5 to 15% by weight, and Cr is 0.5 to 3% by weight.

  According to this configuration, the composition is such that Mo is 15 to 30% by weight, Ni is 5 to 15% by weight, and Cr is 0.5 to 3% by weight, and the Ni—Cr phase is the main component of the rotary tool. The composition ratio is 18% by weight or less compared with TiC-Mo. By setting each component to such a lower limit value or more, the material of the rotary tool can be strengthened, and by setting it to the upper limit value or less, a decrease in strength can be prevented. Furthermore, by making the Ni—Cr phase 18% by weight or less in this way, the deformation of the rotary tool at high temperatures can be suppressed by narrowing the distance between TiC—Mo particles.

  In this case, the average particle size of TiC is preferably in the range of 0.5 to 3 μm.

  According to this configuration, the average particle size of TiC is in the range of 0.5 to 3 μm. By setting the thickness to 0.5 μm or more, the tool material can be made strong, and by setting the thickness to 3 μm or less, strength reduction can be prevented. Thus, by reducing the size of the TiC particles as much as possible and reducing the distance between the TiC particles, deformation of the rotating tool at high temperatures can be suppressed.

  Further, at least the tip of the rotary tool may contain at least one compound selected from TiN, TaN, (W, Ti) C, (W, Ti, Ta) C, and (Ta, Nb) C. Is preferred.

  According to this configuration, at least the tip portion of the rotary tool is at least one compound selected from TiN, TaN, (W, Ti) C, (W, Ti, Ta) C, and (Ta, Nb) C. Therefore, heat resistance and oxidation resistance can be improved.

  Moreover, it is preferable that at least the tip portion of the rotary tool contains at least one compound selected from silicide and boride.

  According to this configuration, silicide and boride are added to the rotating tool. The addition of Si and B compounds to the rotary tool material produces a solid lubrication effect on the rotary tool surface, thereby reducing the frictional resistance between the rotary tool and the metal material. Therefore, it is possible to increase the rotational speed of the rotary tool. In this case, the frictional heat is generated by increasing the rotational speed of the rotating tool, but at the same time, the moving speed of the tool is relatively reduced, so that the bending stress is reduced. At the same time, since welding with the joining member on the surface of the rotating tool is also reduced, stress concentration on the tool is avoided, and breakage of the rotating tool can be prevented.

  In this case, it is preferable that the content of at least one compound selected from silicide and boride in the rotary tool decreases from the surface portion to the inside of the rotary tool.

  Since the solid lubrication effect due to the addition of silicide or boride may be generated at the surface portion of the rotary tool, the content of silicide or boride decreases from the surface portion to the inside of the rotary tool, so that the minimum addition amount Thus, the effect of addition of silicide or boride can be improved.

  According to the rotary tool of the present invention, it is possible to provide a rotary tool having a longer life even for a metal material that is difficult to be bonded or surface-modified.

It is a perspective view showing an example of a rotation tool concerning an embodiment. It is a perspective view which shows another example of the rotary tool which concerns on embodiment. It is a perspective view which shows the friction stirring process of the manufacturing method of the metal material which concerns on embodiment. It is a manufacturing method of the metal material concerning an embodiment, and is a perspective view showing spot type friction stir processing. It is a manufacturing method of the metal material concerning an embodiment, and is a perspective view showing superposition type friction stirring processing. It is a manufacturing method of the metal material concerning an embodiment, and is a perspective view showing a superposition type spot type friction stir processing. It is the table | surface summarized about the Rockwell hardness and composition of the rotary tool used in the experiment example. It is the table | surface which put together the result of each experimental example. It is a phase diagram of carbon steel. It is a perspective view which shows the rotary tool of this embodiment after joining Ti alloy. It is a perspective view which shows the rotary tool of this embodiment after joining Ti alloy. It is a perspective view which shows the rotary tool of this embodiment after joining Ti alloy. It is a perspective view which shows the rotary tool of this embodiment after joining Ti alloy. It is a perspective view which shows the conventional rotary tool after joining Ti alloy. It is a figure which shows the joining possible range of pure Ti in friction stir welding. It is a figure which shows the joining possible range of pure Ti with the rotary tool of probe diameter 6mm. It is a figure which shows the joining possible range of pure Ti with the rotating tool of 4 mm of probe diameters. It is a top view which shows the junction part of a favorable junction state. It is a top view which shows the junction part which the groove-like defect produced. It is a top view which shows the junction part of an unstable joining state. It is sectional drawing which shows the junction part which the defect produced inside. It is a figure which shows the range which the base material according to a probe diameter fractures | ruptures, and the range which a stirring part fractures | ruptures. It is a figure which shows the temperature dependence of stability of metal glass and each phase. It is a side view which shows the rotation tool from which each dent angle differs. It is a top view which shows the junction part by the rotary tool whose dent angle is 10 degrees. It is a top view which shows the junction part by the rotary tool whose dent angle is 0 degree. It is a top view which shows the junction part by the rotation tool whose dent angle is 3 degrees. It is a top view which shows the junction part by the rotation tool whose dent angle is 3 degrees.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In the present embodiment, a rotating tool 100a as shown in FIG. 1 is prepared. As shown in FIG. 1, the tool includes a shoulder 101 having a large diameter and a probe 102a at the tip thereof. As shown in FIG. 3, at the time of friction stir welding, the ends of the metal materials 1 a and 1 b are put together to form a joint 20. Only the probe 102a is pushed into the joint 20 and rotated along the butting surface to be joined. In the friction stir welding, bonding is performed by plastic flow by friction stirring of the rotary tool 100a. The shoulder 101 rotates while the probe 102a enters the metal materials 1a and 1b, and acts as a heat source by suppressing the metal materials 1a and 1b from being discharged to the outside and by friction with the surfaces of the metal materials 1a and 1b. It plays both roles.

  As the metal materials 1a and 1b, in addition to a general Al material and ordinary steel, as described later, high carbon steel, Ti alloy, pure Ti, heat-resistant steel, and metallic glass, which are difficult to be bonded or surface-modified as described later. It is possible to increase the limit plate thickness in the case of ordinary steel or Al alloy. Moreover, it does not ask | require whether it is the same kind material or different materials as metal material 1a, 1b. Further, the number of the metal materials 1a and 1b is not limited to one or two, but three or more metal materials can be simultaneously brought into contact with or close to each other at the joint 20 and can be processed simultaneously.

  In addition, as shown in FIG. 2, it is also possible to apply the rotary tool 100b which has the probe 102b by which the screw-shaped groove | channel 103 was provided in the outer periphery. In this aspect, the screw-like groove 103 provided on the outer periphery of the probe 102b has an advantage that the plastic flow of the metal materials 1a and 1b is promoted and good bonding can be obtained.

  In addition to the embodiment shown in FIG. 3, the friction stir processing in the present embodiment, as shown in FIG. 4, is a spot type friction stirrer that continues to rotate at the same location of the metal material 1a without moving the rotary tool 100a. A processing mode is also included. Alternatively, as shown in FIG. 5, by joining the plate-like metal materials 1a and 1b, rotating the rotary tool 100a while abutting against the metal material 1a, and moving the metal tool 1a, the joint portion 20 is obtained. Superposition joining which stirs may be performed. Also in this case, as shown in FIG. 6, spot-type friction stir welding without the movement of the rotary tool 100 a can be performed. 3 to 6, it is possible to modify the surface of the metal material 1 a and the like in addition to joining the metal material 1 a and the like. Note that the probe 102a is not essential when the surface of the metal material 1a or the like is modified. Further, the metal material 1a or the like is a thin plate, and the probe a is not necessary when performing the friction stir welding. In this case, the shoulder 101 comes into contact with the metal material 1a or the like as the tip of the rotary tool 100a.

  As a material of the rotary tools 100a and 100b of this embodiment, a WC-Ni-Cr-based material, a WC-Co-Ni-Cr-based material, or a TiC-Mo-Ni-Cr-based material is used. The present inventors have found that the above problem can be solved by using Ni for the metal phase in the material composition of the rotary tool. The high-temperature stable phase of iron is austenite, the crystal structure is face-centered cubic, and the crystal structure of Ni is the same. For this reason, the Ni metal phase is excellent in high temperature strength. Furthermore, in the Ni—Cr phase in which Cr is solid-dissolved, the strength is improved by solid solution strengthening and the characteristics are excellent in thermal stress, oxidation resistance, and corrosion resistance. As a result, in the WC—Ni—Cr alloy, the welding resistance is greatly improved as compared with the WC—Co alloy. For this reason, since the frictional resistance generated at the time of friction stir welding is stabilized, stress concentration due to (frictional resistance + bending stress) accompanying an unexpected increase in frictional resistance at the time of welding is avoided, and breakage of the rotary tools 100a and 100b is prevented. Can be prevented.

  Further, in a WC-Co-Ni-Cr alloy obtained by adding Co to a WC-Ni-Cr alloy having a composition further containing Co, the rotating tools 100a and 100b are generated during friction stir welding by forming a tougher metal phase. And the metal materials 1a and 1b can have a necessary and sufficient proof strength against the frictional resistance and bending stress. In addition, with Co—Ni—Cr, the thermal crack resistance can be improved.

  Further, even when a TiC-Mo-Ni-Cr-based material in which the WC phase is replaced with a TiC-Mo phase is used, the above-described rotating tool 100a of the WC-Ni-Cr-based alloy or the WC-Co-Ni-Cr-based alloy is used. , 100b can be obtained. In this case, the addition of Mo is for the purpose of improving the wettability of the TiC phase and suppressing particle growth, and Mo is for forming hard particles with TiC. Furthermore, WC is very expensive as a rare metal, and in recent years, the need for recycling is also increasing as a national policy. Therefore, the ability to replace WC with TiC ensures stable supply in terms of resources. Moreover, TiC is excellent in hardness compared with WC. Incidentally, while WC is HV = 1800, TiC is about HV = 3200. Because of this characteristic difference, the wear amount of the rotary tools 100a and 100b is reduced, so that the tool life can be extended.

  The raw materials of the rotary tools 100a and 100b are WC powder, Ni powder, Cr-C powder, etc. as a starting material, and a predetermined amount is weighed, mixed, then compacted, machined into a tool material shape, 1350 Heat sintering in a temperature range of ℃ or higher, and further HIP treatment to obtain a dense alloy material. The rotary tools 100a and 100b are completed by grinding the obtained sintered material with a diamond tool. The Rockwell hardness is preferably HRA = 85 to 95, more preferably HRA = 90 to 94, the bending strength is 2.5 GPa or more, and the compressive strength is 5 GPa or more as the mechanical properties of the materials of the rotary tools 100a and 100b. Is a preferred range.

  The range of 0.2 to 2.5 μm is applied to the WC grain size used for the material of the rotary tools 100a and 100b. When the thickness is 0.2 μm or more, the material becomes extremely strong, and when the thickness is 2.5 μm or less, a decrease in strength can be prevented. Preferably, a WC particle size in the range of 0.5 to 1.5 μm is applied. Thus, by reducing the size of the WC particles as much as possible and reducing the distance between the WC particles, the deformation of the rotary tools 100a and 100b at a high temperature can be suppressed.

  In the WC-Ni-Cr composition, it is appropriate that Ni is 2 to 15% by weight and Cr is 0.3 to 3% by weight. By setting Ni to 2% by weight or more, the material of the rotary tools 100a and 100b can be obtained. It can be made strong, and by making it 15% by weight or less, strength reduction can be prevented. Further, when Cr is 0.3% by weight or more, oxidation resistance is improved, and when it is 3% by weight or less, strength reduction can be prevented. Furthermore, by setting the Ni—Cr phase to a composition ratio of 18% by weight or less, the distance between the WC particles can be narrowed, and deformation of the rotary tools 100a and 100b at high temperatures can be suppressed. More preferably, Ni is 5 to 12% by weight and Cr is 0.3 to 1.5% by weight. Moreover, the more preferable range as Ni-Cr is 6 to 12 weight%.

  In the WC-Co-Ni-Cr composition, the ranges of 3-12% by weight of Co, 1-6% by weight of Ni, and 0.2-2% by weight of Cr are suitable. Similarly, when the Co content is 3% by weight or more, the oxidation resistance is improved, and when the Co content is 12% by weight or less, a decrease in strength can be prevented. Preferred composition ranges are 5 to 9% by weight of Co, 2 to 5% by weight of Ni, and 0.3 to 1.5% by weight of Cr. Furthermore, by setting the Co—Ni—Cr phase to a composition ratio of 18% by weight or less, the distance between WC particles can be narrowed, and deformation of the rotating tool at high temperatures can be suppressed. Moreover, the more preferable range as Co-Ni-Cr is 7 to 12 weight%.

  In the TiC-Mo-Ni-Cr composition, the TiC average particle size is suitably in the range of 0.5 to 3 μm, and by making it 0.5 μm or more, the tool material is made strong, and by making it 3 μm or less, Strength reduction can be prevented. A more preferable particle size range is 1 to 2 μm. Thus, by reducing the size of the TiC particles as much as possible and reducing the distance between the TiC particles, deformation of the rotary tools 100a and 100b at high temperatures can be suppressed.

  In the composition, the ranges of 15 to 30% by weight of Mo, 5 to 15% by weight of Ni, and 0.5 to 3% by weight of Cr are appropriate, and the rotary tools 100a and 100b are set by setting each component to the lower limit value or more. This material can be made strong, and strength reduction can be prevented by setting it to the upper limit value or less. More preferable composition ranges are 18 to 25% by weight of Mo, 6 to 12% by weight of Ni, and 0.5 to 1.5% by weight of Cr. Furthermore, by setting the Ni—Cr phase to a composition ratio of 18% by weight or less, the distance between TiC particles can be narrowed, and deformation of the rotating tool at high temperatures can be suppressed. Moreover, the more preferable range as Ni-Cr is 6-12 wt%.

  Further, at least one compound selected from TiN, TaN, (W, Ti) C, (W, Ti, Ta) C, and (Ta, Nb) C is added to the material of the rotary tools 100a and 100b. Thereby, heat resistance and oxidation resistance can be improved.

In this embodiment, silicide (SiC, Si ₃ N ₄ etc.), boride (B ₄ C, BN etc.) or P (phosphorus) can be added to the material of the rotary tools 100a, 100b. The addition amount of silicide or boride is extremely small and exhibits a solid lubricating effect. The content of Si is sufficient in the range of 0.02 to 0.1% by weight, and the range of 20 to 500 ppm is appropriate for the content of B. By setting it to these lower limit values or more, the effect can be reliably exerted, and by setting these upper limit values or less, strength reduction can be prevented. These additive elements including silicide, boride or P are specific elements located between metal and nonmetal. By impregnating the surface of the material of the rotary tools 100a and 100b with these additive elements, the content of silicide and the like can be reduced from the surface part of the rotary tools 100a and 100b to the inside, and the minimum addition The effect of addition of silicide or the like can be increased by the amount.

  Hereinafter, an experimental example in which different kinds of metal materials are subjected to friction stir welding using a rotary tool having different kinds of compositions will be described. In the following experimental examples, experiments were performed using rotating tools of prototype numbers A to J having the Rockwell hardness and composition shown in FIG. Moreover, the result shown in FIG. 8 was obtained by each rotation tool. Below, the result for every metal material is demonstrated.

(Experimental example 1: High carbon steel)
As a high carbon steel, SK5 material was used as a metal material 1a, 1b as a sample, and friction stir welding was performed as shown in FIG. SK5 material is C: 0.85 wt%, Mn: 0.42 wt%, Si: 0.19 wt%, Cr: 0.147 wt%, P: 0.017 wt%, Cu: 0.01 wt% %, Ni: 0.01% by weight, S: 0.003% by weight, Al: 0.001% by weight, and the remaining Fe.

  As the rotary tool 100a used in this experimental example, a tool having a shoulder 101 diameter of 12 mm, a probe 102a diameter of 4 mm, and a probe 102a length of 1.5 mm was used for any composition. In addition, as for the joining conditions, for any composition, the tilt angle of the rotary tool 100a is 3 °, the rotational speed of the rotary tool is 100 to 400 rpm, the joining speed is 100 to 200 mm / min, and the rotational pitch (joining speed / rotation). Speed) was 0.5 to 1 mm / r.

In this experimental example, in the phase diagram of the carbon steel shown in FIG. 9, bonding is performed at a rotation speed of 400 rpm and a bonding speed of 200 mm / min at A ₁ point (723 ° C.) or higher, and at a rotational speed of 100 rpm and a bonding speed at A ₁ point or lower. Joining was performed at 100 mm / min.

  In Experimental Examples 1 to 5 shown below, since the length along the joining direction of the metal materials 1a and 1b is 300 mm, when the joining of one set of the metal materials 1a and 1b is completed, the next set of metals The materials 1a and 1b were sequentially joined, and the average joining length was evaluated as the life of the rotating tool with respect to the total joining length of three tools for one kind of rotating tool.

As shown in FIG. 8, it can be seen that the rotary tools 100a of trial numbers A, E, and H having the composition of the present invention have a longer life than the rotary tools of trial numbers I and J having the conventional composition. . In particular, when joining is performed at a rotational speed of 400 rpm and a joining speed of 200 mm / min at _one point or more, the average joining length of the rotating tools of trial number I (WC-Co) and trial number J (WC-Co-TaC). The average junction length of the trial number A (WC-Ni-Cr) is 25 m, while the average junction length of the trial number E (WC-Co-Ni-Cr) is 25 m. The average joint length of prototype No. H (TiC-Mo-Ni-Cr) was 40 m, 5-8 times longer.

In addition, when joining is performed at a rotational speed of 100 rpm and a joining speed of 100 mm / min at ₁ point or less, the average joining length of the rotating tools of trial number I (WC-Co) and trial number J (WC-Co-TaC) However, the average joint length of the prototype No. A (WC-Ni-Cr) is 24 m, and the average joint length of the prototype No. E (WC-Co-Ni-Cr) is 30 m and 8 Lifespan improved by 10 times. Note that, in any joining condition and rotating tool, the joining surface was good.

(Experimental example 2: Ti alloy)
Friction stir welding was performed as shown in FIG. 3 using Ti-6Al-4V material as a Ti alloy as metal materials 1a and 1b. The thickness of the Ti-6Al-4V material was 2 mm, and bonding was performed at a rotation speed of 400 rpm and a bonding speed of 200 mm / min.

  From FIG. 8, prototype number A (WC-Ni-Cr), prototype number B (WC-Ni-Cr-TaN), prototype number C (WC-Ni-Cr- (W, Ti, Ta) C), prototype number. D ((WC-Ni-Cr) added to surface part B), trial production number E (WC-Co-Ni-Cr), trial production number F (WC-Co-Ni-Cr-TaC) and trial production number G ( (Adding B to the surface portion of WC-Co-Ni-Cr) shows that the life of the rotary tool 100a is extremely long. In particular, the prototype number E (WC-Co-Ni-Cr) shown in FIG. 10, the prototype number F (WC-Co-Ni-Cr-TaC) shown in FIG. 11, and the prototype number G ((WC-Co) shown in FIG. It can be seen that no damage is observed in the rotating tool 100a when B with a particle size of 1.5 μm is added to the surface portion of (Ni—Cr). Further, it can be seen that even the trial production number G shown in FIG. 13 ((WC—Co—Ni—Cr) with B having a particle size of 6 μm added to the surface portion) remains slightly damaged. On the other hand, as shown in FIG. 14, the tip of the conventional rotary tool 10 with the trial production number I (WC-Co) and the trial production number J (WC-Co-TaC) was broken, and joining was impossible.

(Experimental example 3: Pure Ti)
Friction stir welding was performed as shown in FIG. 3 using industrial pure Ti (cp-Ti: 99.9%) material as metal materials 1a and 1b as samples. The thickness of the pure Ti material was 2 mm, and bonding was performed at a rotation speed of 300 to 550 rpm and a bonding speed of 50 to 250 mm / min. Ar gas was used as the shielding gas. The rotary tools 100a and 10 used in this experimental example have a shoulder 101 diameter of 15 mm, a probe 102a diameter of 4 mm, 5 mm and 6 mm, and a probe 102a length of 2.0 mm, regardless of the composition. It was used.

  As shown in FIG. 15, since pure Ti has an hcp structure at 885 ° C. or less, it is difficult to be plastically deformed, and the joining conditions under which pure Ti material can be joined are extremely narrow compared to other Al6061 materials and the like. I understand that. 16 and 17 show the results of experiments conducted by changing the rotation speed and the joining speed. FIG. 16 shows the result of the probe 102a having a diameter of 6 mm, and FIG. 17 shows the result of the probe 102a having a diameter of 4 mm. The white circle plots in FIGS. 16 and 17 indicate that a good joint 20 as shown in FIG. 18 was obtained, and the black circle plot shows that a groove-like defect as shown in FIG. The hatched circle plot indicates that the joint 20 in an unstable bonding state as shown in FIG. 20 is obtained, and the triangular plot indicates that a defect as shown in FIG.

  As shown in FIG. 16, when the diameter of the probe 102a is 6 mm, bonding is possible when the bonding speed is relatively low, 125 mm / min or less, and good bonding can be obtained at a bonding speed of 75 mm / min or less. I understand. On the other hand, as shown in FIG. 17, when the diameter of the probe 102a is 6 mm, the range in which bonding is possible is widened, and bonding is possible when the bonding speed is relatively fast, 200 mm / min or less. It can be seen that it can be obtained at 100 mm / min or less. When the diameter of the probe 102a is 6 mm, particularly good bonding can be obtained at a rotation speed of 350 to 450 rpm and a bonding speed of 100 mm / min.

  As shown in FIG. 22, when the diameter of the probe 102a is 4 mm, the base material breaks when the tensile test is performed on the joint portion 20 as compared with the case where the diameter of the probe 102a is 5 mm and 6 mm. It can be seen that the range in which the strength of the joint 20 is improved is wider than that of the metal materials 1a and 1b which are the base materials.

  In the case where the diameter of the probe 102a is 4 mm, the average joint length of the rotary tool 10 of the trial production number I (WC-Co) and the trial production number J (WC-Co-TaC) remained at 2.4 m. The average junction length of number A (WC-Ni-Cr) is 48 m, the average junction length of trial number B (WC-Ni-Cr-TaN) is 150 m, and trial number E (WC-Co-Ni). The average joint length of -Cr) was 150 m, which was improved by 20 to 60 times or more.

(Experimental example 4: heat resistant steel)
Similar to the experimental example 1 described above, an experiment was performed on heat resistant steel. While the average joining length of the rotary tool 10 of the trial production number I (WC-Co) and the trial production number J (WC-Co-TaC) was extremely short, B was added to the trial production number D ((WC-Ni-Cr)). Trial number E (WC-Co-Ni-Cr), Trial number G (B added to (WC-Co-Ni-Cr), surface part), Trial number H (TiC-Mo-Ni) -Cr) The average joining length of the rotary tool 100a is 8 to 10 times longer.

(Experimental example 5: Metallic glass)
Friction stir welding was performed as shown in FIG. 3 using Zr ₅₅ Cu ₃₀ Al ₁₀ Ni ₅ material as metal glass as metal materials 1a and 1b as samples. The thickness of the Zr ₅₅ Cu ₃₀ Al ₁₀ Ni ₅ material is 2 mm. Metallic glasses as in metallic glass and each phase temperature dependence shown in FIG. 23, there is supercooled liquid region (SUPERCOOLED LIQUID) between the glass transition temperature T _g and the crystallization temperature T _x. The molding in the supercooled liquid region are possible, there is the crystallization to be the crystallization temperature T _x problem. Therefore, in this experimental example, bonding was performed by joining conditions of rotational speed 80~200rpm and welding speed 100 mm / min becomes less has a glass transition temperature _{T g} higher than the crystallization temperature _{T x.}

  In this experimental example, a rotating tool having a screw-like groove 103 provided on the side surface of the probe 102b to the left is used as in the rotating tool 100b shown in FIG. 2 for any composition. The shoulder 101 has a diameter of 25 mm, which is larger than those of Experimental Examples 1 to 4 described above. This is because generation of burrs can be prevented when the diameter of the shoulder 101 is set to 25 mm, rather than about 12 mm. The diameter of the probe 102b was 5 mm.

  When the dent angle (angle formed by the shoulder 101) θ is 10 ° as in the rotary tool 100c of FIG. 24, heat is concentrated on the shoulder 101, and the joint 20 may be biased toward the periphery as shown in FIG. There is. Further, when the dent angle θ is 0 ° as in the rotary tool 100e, there is a possibility that the joint 20 has many burrs as shown in FIG. Therefore, in this experimental example, a tool having a recess angle θ of 3 °, such as the rotary tool 100d, was used. In practice, the indentation angle θ is preferably 2 to 5 °.

  FIG. 27 shows the joint 20 that was tested at a rotational speed of 150 rpm and a joining speed of 100 mm / min using the rotary tool with a dent angle θ of 3 °. FIG. 28 shows a rolling speed of 100 rpm and a joining speed of 100 mm / min. The joining part 20 which experimented is shown. In all cases, there were relatively few burrs around the bead and no major defects were observed.

  From FIG. 8, prototype number C (WC-Ni-Cr- (W, Ti, Ta) C), prototype number D ((WC-Ni-Cr) with B added to surface portion), prototype number F (WC- In Co-Ni-Cr-TaC) and trial production number G ((WC-Co-Ni-Cr) with B added to the surface portion), it can be seen that the life of the rotary tool 100d is extremely long. In particular, while the average joint length of the rotary tools of the trial number I (WC-Co) and the trial number J (WC-Co-TaC) remained at 0.6 m, the trial number C (WC-Ni-Cr- The average joint length of (W, Ti, Ta) C) is 4.2 m, and the average joint length of prototype No. D ((WC-Ni-Cr) with B added to the surface part) is 6 m and 7 to 7 Lifespan improved 10 times.

  In the above experimental examples 1 to 5 in general, the use of Ni for the metal phase of the rotary tools 100a, 100b, and 100d prevents welding between the probes 102a and 102b and the metal materials 1a and 1b. In addition, it can be said that the improvement of the thermal crack resistance of the shoulder 101 significantly reduced the defects.

  It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1a, 1b ... Metal base material, 10 ... Rotary tool, 20 ... Joint part, 100a-100e ... Rotary tool, 101 ... Shoulder, 102a, 102b ... Probe, 103 ... Screw-shaped groove | channel.

Claims (10)

A rotating tool used in a method for treating a metal material, in which the tip of the rotating tool is brought into contact with a stirring portion of a metal material while rotating a rod-shaped rotating tool, and the metal material is bonded or surface-modified. There,
At least the tip portion of the rotary tool is made of a composition containing WC, Ni 2 , Cr and Co , and the Rockwell hardness is in a range of HRA = 85 to 95.   The rotary tool according to claim 1, wherein at least the tip portion of the rotary tool has a composition in a range of Ni of 2 to 15 wt% and Cr of 0.3 to 3 wt%. At least the tip portion of the rotary tool, Co 3 to 12 wt%, Ni is 1 to 6 wt% and Cr a composition in the range of 0.2 to 2% by weight, according to claim 1 or 2 Rotating tool. The rotating tool according to any one of claims 1 to 3 , wherein an average particle size of WC is in a range of 0.2 to 2.5 µm. A rotating tool used in a method for treating a metal material, in which the tip of the rotating tool is brought into contact with a stirring portion of a metal material while rotating a rod-shaped rotating tool, and the metal material is bonded or surface-modified. There,
At least the tip of the rotary tool is made of a composition containing TiC, Mo, Ni and Cr, and the Rockwell hardness is in the range of HRA = 85 to 95. The rotary tool according to claim 5 , wherein at least the tip of the rotary tool has a composition in a range of Mo of 15 to 30 wt%, Ni of 5 to 15 wt%, and Cr of 0.5 to 3 wt%. . The rotating tool according to claim 5 or 6 , wherein the average particle size of TiC is in the range of 0.5 to 3 µm. At least the tip portion of the rotating tool includes at least one compound selected from TiN, TaN, (W, Ti) C, (W, Ti, Ta) C, and (Ta, Nb) C. Item 8. The rotating tool according to any one of Items 1 to 7 . The rotary tool according to any one of claims 1 to 8 , wherein at least the tip portion of the rotary tool includes at least one compound selected from silicide and boride. The rotary tool according to claim 9 , wherein the content of at least one compound selected from silicide and boride in the rotary tool decreases from the surface portion to the inside of the rotary tool.