JP6624725B2 - Method for manufacturing pipe having porous metal layer - Google Patents

Description

The present invention relates to a method for manufacturing a pipe having a porous metal layer.

  Porous metal containing many air bubbles is lightweight and has excellent impact energy absorbing properties and sound deadening properties, and is attracting attention as an ultralight multifunctional material in various fields such as automobiles, railways, aerospace, and construction.

  However, the conventionally proposed method of producing a porous metal from a metal powder is expensive and hinders its practical use.

  Then, the inventors of the present invention produced a precursor for foamed metal by joining two flat base materials by placing a foaming agent between them and then superposing them, and then joining them by friction stirring. A method of producing a foamed metal by heating and foaming a metal precursor has been proposed. (For example, refer to Patent Document 1).

International Publication No. WO 2010/029864

  In order to further improve the function of the porous metal, it is conceivable to combine the porous metal with another structural material. For example, it is conceivable to form a porous metal inside or outside a metal pipe and to combine the pipe and the porous metal.

  However, the method described in Patent Literature 1 produces a porous metal from a plate-like precursor, and thus cannot be applied to the case of producing a porous metal in a closed space such as a pipe.

In order to solve the above-described problems, the present invention provides a method for manufacturing a pipe having a porous metal layer, which enables formation of layers having various functions and characteristics including a porous metal layer in the pipe. Things.

  The method for producing a pipe having a porous metal layer according to the present invention is characterized in that a plurality of layers different from the adjacent layers are sequentially formed one by one from outside to inside by plastic flow utilizing frictional heat by a tool. Forming at least one layer of the plurality of layers as a metal layer containing a foaming agent, and forming at least one layer as a metal layer containing no foaming agent; By heating the body, the metal is foamed using the foaming agent of the precursor to form a porous metal layer from the metal layer containing the foaming agent, and the metal not containing the foaming agent. Forming a metal pipe from the layers.

  In the method for manufacturing a pipe having a porous metal layer according to the present invention, at least one layer from the outermost of the plurality of layers is a metal layer containing the foaming agent, and a layer inside the metal layer containing the foaming agent is It is also possible to form the porous metal layer outside the metal pipe by preparing the precursor that is a metal layer that does not contain the foaming agent and heating the precursor.

  In the method for manufacturing a pipe having a porous metal layer according to the present invention, at least one layer from the outermost of the plurality of layers is a metal layer not containing the foaming agent, and a layer inside the metal layer not containing the foaming agent. It is also possible to form the porous metal layer inside the metal pipe by preparing the precursor whose layer is a metal layer containing the foaming agent and heating the precursor.

According to the method of manufacturing a pipe having a porous metal layer of the present invention described above, at least one of the plurality of layers is formed as a metal layer containing a foaming agent, and at least one layer contains a foaming agent. Formed as a non-metallic layer, and then foamed the metal using a foaming agent to form a porous metal layer from the metal layer containing the foaming agent, and a metal pipe from the metal layer without the foaming agent. To form Thereby, a porous metal layer can be formed in contact with the metal pipe. Various functions and characteristics of the porous metal layer can be realized in the pipe.
Further, since the metal pipe is formed from the metal layer of the plurality of layers that does not contain the foaming agent, the porous metal layer can be formed in contact with the metal pipe without preparing a ready-made metal pipe. . As a result, the material and dimensions of the metal pipe are smaller than when a porous metal layer is formed on the metal pipe using an off-the-shelf metal pipe with limited materials, dimensions (thickness, outer diameter, etc.) It is possible to increase the degree of freedom in designing the shape and shape.

FIGS. 3A to 3D are manufacturing process diagrams showing the manufacturing process of the first embodiment of the pipe manufacturing method of the present invention. FIGS. FIGS. 3A to 3H are manufacturing process diagrams showing the manufacturing process of the first embodiment of the pipe manufacturing method of the present invention. FIGS. 1A to 1K are manufacturing process diagrams showing a manufacturing process according to a first embodiment of a pipe manufacturing method of the present invention. FIGS. 9A to 9D are manufacturing process diagrams illustrating manufacturing processes according to a second embodiment of the pipe manufacturing method of the present invention. FIGS. FIGS. 8A to 8H are manufacturing process diagrams illustrating manufacturing processes according to a second embodiment of the pipe manufacturing method of the present invention. It is sectional drawing of the laminated metal material on which the metal material from which a material differs was laminated | stacked.

  In the method for producing a pipe having a porous metal layer according to the present invention, a plurality of layers different from adjacent layers are sequentially formed from outside to inside one by one by a plastic flow utilizing frictional heat generated by a tool. Forming at least one layer of a plurality of layers as a metal layer containing a foaming agent, that is, a porous metal layer precursor, and forming at least one layer as a metal layer containing no foaming agent. Having. After that step, the metal is foamed using the foaming agent inside the precursor by heating the precursor to form a porous metal layer from the metal layer containing the foaming agent, and the foaming agent is included. Forming a metal pipe from a metal layer that is not present.

In the manufacturing method of the present invention, one or more outermost layers of the plurality of layers are a metal layer containing a foaming agent, and a layer inside the metal layer containing a foaming agent is a metal layer containing no foaming agent. A porous metal layer may be formed outside the metal pipe by preparing a body and heating the precursor.
In the method of the present invention, at least one of the outermost layers of the plurality of layers is a metal layer containing no foaming agent, and a layer inside the metal layer containing no foaming agent contains a foaming agent. The precursor may be prepared, and the precursor may be heated to form a porous metal layer inside the metal pipe.

In the production method of the present invention, it is possible to form two or more metal layers containing a foaming agent or a metal layer containing no foaming agent. In particular, when two or more layers are formed next to each other, a porous metal layer or a metal pipe in which the material sequentially changes can be formed.
However, if a metal layer containing a foaming agent is sandwiched between two metal layers containing no foaming agent, expansion due to foaming is suppressed, which is not preferable. When two or more metal layers containing no foaming agent are formed, they are preferably formed adjacent to each other.

In the manufacturing method of the present invention, various metal elements and alloys of the metal elements can be used as the metal material to be the material of the metal layer. Any metal material can be used as long as it can be plastically flowed by utilizing frictional heat generated by the tool. Suitable metal materials include, for example, aluminum and its alloys, magnesium and its alloys, titanium and its alloys, iron and steel materials, copper and its alloys, and the like.
However, if the metal layer containing no foaming agent is formed of a metal material having a melting point equal to or less than the metal layer containing the foaming agent, when the precursor is heated to form a porous metal layer, Since there is a possibility that the metal containing no foaming agent is deformed or the pores are eroded, it is difficult to combine the metal pipe and the porous metal layer. Therefore, the metal layer containing no foaming agent is preferably formed of a metal material having a higher melting point than the metal layer containing a foaming agent.

In the production method of the present invention, as the foaming agent, various conventionally known foaming agents, for example, titanium hydride, zirconium hydride, calcium carbonate, and the like can be used.
For the metal layer containing a foaming agent, a solid material, a powder, or the like obtained by mixing a metal material and a foaming agent can be used as a raw material.

In the manufacturing method of the present invention, the sequential formation of a plurality of layers by plastic flow utilizing frictional heat generated by a tool can be specifically performed, for example, as follows.
First, a material (solid metal or powder of metal or a mixture thereof with a foaming agent) serving as a raw material of the first layer is placed in a space inside the cylindrical jig, and the cylindrical jig is placed. The first layer is formed between the tool and the cylindrical jig by plastic flow utilizing frictional heat generated by a tool having an outer diameter smaller than the inner diameter of the tool. At this time, the metal is not melted but softened by the frictional heat, and the first layer is formed.
Next, a material serving as a raw material for the second layer is placed in the space inside the first layer, and a plastic flow using frictional heat is performed using a tool having a smaller outer diameter than the previous tool, A second layer is formed between the tool and the first layer.
Thereafter, using a tool whose outer diameter is smaller than that of the previous tool, plastic flow using frictional heat is repeated to form the first layer to the n-th layer (n is an integer of 2 or more). .

  When one or more of the outermost layers of the plurality of layers of the precursor are formed of a metal layer containing a foaming agent, the precursor expands outward when the metal foams using the foaming agent by heating the precursor. Therefore, it is desirable to provide a jig outside the precursor in order to control the expansion. The jig in this case is preferably a cylindrical shape in which the space inside the jig is a cylinder, but is not limited to a cylindrical shape, for example, a shape in which the space inside the jig is a triangular prism or a square prism. It does not matter.

  Pipes having a porous metal layer and pipes having a porous metal layer of the present invention, which are manufactured by the manufacturing method of the present invention, include, for example, automobile parts, aerospace-related parts, civil engineering and building components, railway-related parts, and industrial products. It can be applied to various products such as machine parts, sporting goods, biotechnology, heat exchangers, etc.

Next, a first embodiment of the pipe manufacturing method of the present invention will be described with reference to FIGS.
In the present embodiment, a pipe is manufactured with a two-layer structure in which the inner layer is a metal pipe and the outer layer is a porous metal layer.

First, as shown in the cross-sectional view of FIG. 1A, a cylindrical jig 112 is set on a flat jig 111, and a foaming agent is placed in a space formed by these jigs 111 and 112. The first metal 11 containing is placed. As the first metal 11, a metal element such as aluminum or an alloy can be used, and as the foaming agent, the various foaming agents described above, for example, titanium hydride (TiH ₂ ) can be used.

Next, as shown in FIG. 1B, the first metal 113 shown in FIG. 1A is pressed by rotating a first tool 113 having an outer diameter smaller than the inner diameter of the cylindrical jig 112 while rotating the first tool 113 from above. Is caused to flow plastically using frictional heat to form the first metal layer 12.
The first metal layer 12 contains a foaming agent and is a precursor of a porous metal layer.
FIG. 1C shows a state in which the process of FIG. 1B is completed and the first tool 113 is removed. As shown in FIG. 1C, a first metal layer 12 containing a foaming agent is formed along the inner wall of the cylindrical jig 112.

  Next, as shown in FIG. 1D, a second metal 13 containing no foaming agent is placed inside the first metal layer 12. As the second metal 13, a metal element such as aluminum or an alloy can be used.

Next, as shown in FIG. 2E, the second metal 114 shown in FIG. 1D is pressed by rotating the second tool 114 having an outer diameter smaller than the outer diameter of the first tool 113 while rotating the second tool 114 from above. 13 is caused to flow plastically using frictional heat to form a second metal layer 14.
The second metal layer 14 is a metal layer containing no foaming agent.
FIG. 2F shows a state in which the step of FIG. 2E has been completed and the second tool 114 has been removed. As shown in FIG. 2F, a second metal layer 14 is formed along the inside of the first metal layer 12.

  Next, as shown in FIG. 2G, the jigs are taken out of the jigs 111 and 112 and cut along a plane indicated by a chain line 200 in the figure. This forms a cylindrical precursor in which the first metal layer 12 is formed on the outside and the second metal layer 14 is formed on the inside, as shown in FIG. 2H.

Next, as shown in FIG. 3I, a cylindrical jig 115 is disposed slightly outside the precursor formed in FIG. 2H.
Subsequently, as shown in FIG. 3J, by heating 116, the metal of the first metal layer 12 is foamed using the foaming agent of the first metal layer 12. Thus, the porous metal layer 15 including the holes 16 is formed. The porous metal layer 15 is formed by expanding until it reaches the outer jig 115. At this time, since the second metal layer 14 does not contain a foaming agent, there is no particular change.

Next, as shown in FIG. 3K, the jig 115 is removed.
As a result, the pipe 10 having the porous metal layer 15 outside the metal pipe made of the second metal layer 14 is formed.

Thus, the pipe 10 having the porous metal layer 15 can be manufactured.
The pipe 10 allows a liquid or gas to flow inside the metal pipe made of the second metal layer 14. Since the porous metal layer 15 is formed outside the metal pipe, heat exchange can be efficiently performed by the porous metal layer 15 having a large surface area, and the pipe 10 having a high heat radiation effect can be configured.

  Further, since the pipe 10 is formed by causing the second metal layer 14 to undergo plastic flow utilizing frictional heat by a tool, the second metal layer 14 is joined to the porous metal layer 15 without any gap. This eliminates the need for an adhesive layer, as compared to a configuration in which a porous metal layer is bonded to a metal layer with an adhesive layer, so that material costs can be reduced.

  Further, according to the manufacturing method of the present embodiment, since the second metal layer 14 of the metal pipe is also formed by performing plastic flow using frictional heat with a tool, the material and dimensions (thickness, outer diameter, etc.) The degree of freedom of the material, dimensions and shape of the metal pipe can be increased as compared with the case where a porous metal layer is formed outside a ready-made metal pipe whose shape and shape are limited. The dimensions of the metal pipe (the second metal layer 14) can be freely set by selecting the outer diameter of the first tool 113 and the outer diameter of the second tool 114.

Next, a second embodiment of the method of manufacturing a pipe according to the present invention will be described with reference to FIGS.
In this embodiment, a pipe is manufactured by using a porous metal layer as an inner layer and a metal pipe as an outer layer in a two-layer structure.

  First, as shown in a cross-sectional view of FIG. 4A, a cylindrical jig 122 is set on a flat jig 121, and a foaming agent is placed in a space formed by these jigs 121. The first metal 21 containing no. As the first metal 21, a metal element such as aluminum or an alloy can be used.

Next, as shown in FIG. 4B, a first tool 123 having an outer diameter smaller than the inner diameter of the cylindrical jig 122 is pushed in while being rotated from above, so that the first metal 21 shown in FIG. Is caused to flow plastically using frictional heat to form the first metal layer 22.
The first metal layer 22 is a metal layer containing no foaming agent.
FIG. 4C shows a state where the first tool 123 is removed after the step of FIG. 4B is completed. As shown in FIG. 4C, the first metal layer 22 is formed along the inner wall of the cylindrical jig 122.

Next, as shown in FIG. 4D, a second metal 23 containing a foaming agent is placed inside the first metal layer 22. As the second metal 23, a metal element such as aluminum or an alloy can be used, and as the foaming agent, the various foaming agents described above, for example, titanium hydride (TiH ₂ ) can be used.

Next, as shown in FIG. 5E, the second metal 124 shown in FIG. 4D is pressed by rotating the second tool 124 having an outer diameter smaller than the outer diameter of the first tool 123 while rotating the second tool 124 from above. The second metal layer 24 is formed by causing a plastic flow using frictional heat to 23.
This second metal layer 24 contains a foaming agent and is a porous metal layer precursor.
FIG. 5F shows a state in which the step of FIG. 5E has been completed and the second tool 124 has been removed. As shown in FIG. 5F, a second metal layer 24 is formed along the inside of the first metal layer 22.

  Next, by taking out from the jigs 121 and 122, a cylindrical precursor in which the first metal layer 22 is formed on the outside and the second metal layer 24 is formed on the inside as shown in FIG. 5G. Is formed.

  Subsequently, by heating the precursor illustrated in FIG. 5G, the metal of the second metal layer 24 is foamed using the foaming agent of the second metal layer 24. Thereby, as shown in FIG. 5H, a porous metal layer 25 including holes 26 is formed from the second metal layer 24. The porous metal layer 25 is formed to expand until it fills the space inside the outer first metal layer 22. At this time, since the first metal layer 22 does not contain a foaming agent, there is no particular change.

After that, if necessary, unnecessary portions, for example, a portion bulging above the first metal layer 22 and a portion near the bottom surface are removed.
Thus, a pipe having the porous metal layer 25 inside the metal pipe made of the first metal layer 22 is formed.

Thus, a pipe having the porous metal layer 25 can be manufactured.
Since this pipe has the porous metal layer 25 and the metal pipe (the first metal layer 22), the inner porous metal layer 25 can reduce the weight of the structural material and realize the shock absorbing properties. Further, the porous metal layer 25 can be reinforced by the outer metal pipe to improve the tensile strength and the bending strength.

  In addition, since the second metal layer 24, which was a precursor of the porous metal layer 25, was formed by performing plastic flow using frictional heat with a tool, the porous metal layer 24 was formed of a metal pipe (first pipe). To the metal layer 22). This eliminates the need for an adhesive layer as compared with a configuration in which a porous metal layer is bonded to an inside of a metal pipe with an adhesive layer, thereby reducing material costs.

  Further, according to the manufacturing method of the present embodiment, since the first metal layer 22 of the metal pipe is also formed by performing plastic flow using frictional heat using a tool, the material and dimensions (thickness, outer diameter, etc.) The degree of freedom in the material, dimensions and shape of the metal pipe can be increased as compared with the case where a porous metal layer is formed inside a ready-made metal pipe whose shape and shape are limited. The dimensions of the metal pipe (second metal layer 14) can be freely set by selecting the inner diameter 122 of the cylindrical jig and the outer diameter 123 of the first tool.

Here, the pipe having the porous metal layer of the present invention was actually manufactured by the respective steps shown in FIGS. 4A to 5H of the second embodiment.
First, as shown in FIG. 4A, a pure aluminum plate was placed as the first metal 21 in the space formed by the flat jig 121 and the cylindrical jig 122. The inner diameter of the cylindrical jig 122 was 20 mm.

  Next, as shown in FIG. 4B, the first metal layer 22 was formed by pressing a first tool 123 having an outer diameter of 15 mm while rotating from above. The rotation speed of the first tool 123 was 800 rpm, and the pushing speed was 5 mm / min.

  Next, the first tool 123 was pulled out while being rotated, and a first metal layer (pure aluminum layer) 22 was formed along the inner wall of the cylindrical jig 122 as shown in FIG. 4C.

Next, an ADC12 precursor was produced as the second metal 23 shown in FIG. 4D. Against ADC12 (Al-Si-Cu alloy) sheet, it was sprayed with a foaming agent (TiH ₂₎ powder 1 wt% and pore forms stabilizer _(Al 2 _{O 3)} powder 5% by weight of the mixed powder.
Next, a plastic flow was generated by scanning while rotating the tool with the projections at a high speed, and the plate material was joined while stirring the powder in the ADC12 plate material to prepare an ADC12 precursor.
The second metal 23 made of the ADC12 precursor thus prepared was placed in the first metal 21.

  Next, as shown in FIG. 5E, the second metal layer 24 was formed by pushing a second tool 124 having an outer diameter of 11 mm while rotating from above. The rotation speed of the second tool 124 was 800 rpm, and the pushing speed was 5 mm / min.

Next, the second tool 124 was pulled out while being rotated, and the second metal layer 24 was formed along the inside of the first metal layer 22 as shown in FIG. 5F.
Subsequently, by taking out from the jigs 121 and 122, a cylindrical precursor in which the first metal layer 22 is formed on the outside and the second metal layer 24 is formed on the inside as shown in FIG. 5G. Got a body.

  Finally, the cylindrical precursor is heated at a temperature of 730 ° C. and a holding time of 4.5 minutes to foam the metal of the second metal layer 24 using the foaming agent of the second metal layer 24 of the precursor. I let it. In this way, as shown in FIG. 5H, a porous metal layer 25 was formed from the second metal layer 24, and a pipe having a core portion of the porous metal layer 25 was manufactured.

  Also, for the above-described example of manufacturing a pipe in which the core portion is the porous metal layer 25, if the order of using the pure aluminum plate and the ADC12 precursor is reversed, the ADC12 is placed outside the metal pipe made of pure aluminum. A pipe having a porous metal layer can be produced.

  In the above-described first and second embodiments, the cylindrical jigs 112 and 122 and the first metal layers 12 and 22 are fixed to each other in order to prevent the jigs 112 and 122 from being fixed and cannot be removed. The inner walls of the jigs 112 and 122 may be made of a metal having a higher melting point than the first metal layers 12 and 22. For example, when the first metal layers 12 and 22 are aluminum or an aluminum alloy, a SUS304 pipe can be used as a metal having a high melting point. Further, in this case, a release agent may be further sprayed on the inner wall surface of the metal having a high melting point to facilitate removal of the metal having a high melting point after forming each metal layer.

In the manufacturing method of the present invention, at least one layer of the layers to be the metal pipe or the porous metal layer may be formed to have a configuration having a plurality of portions each having a different material.
The difference in material for each part may be, for example, a metal element to be used (simple or alloy, a combination of metal elements of the alloy, etc.), a composition of each metal element, and the like.
For example, in each of the above-described embodiments, instead of the illustrated first metals 11 and 21 and the second metals 13 and 23, as shown in a sectional view in FIG. By using the laminated metal material 30 in which the upper and lower metal materials 32 are vertically stacked, it is possible to form a metal pipe or a porous metal layer whose materials are different in the vertical direction.
When the porous metal layer is formed as a structure having a plurality of portions each made of a different material, a metal material for forming each portion contains a foaming agent.

  As described above, in the case where the porous metal layer is configured to have a plurality of portions each having a different material from each other, it is possible to control the order of destruction and control the mechanical characteristics depending on the material.

Reference Signs List 10 pipe, 11 first metal, 12 first metal layer, 13 second metal, 14 second metal layer, 15 porous metal layer, 16 holes, 21 first metal, 22 first metal layer, 23 second metal, 24 second metal layer, 25 porous metal layer, 26 holes, 30 laminated metal material, 31 lower metal material, 32 upper metal material, 111, 112 jig, 113 first tool, 114 second tool, 115 jig, 116 heating, 121, 122 jig, 123 first tool, 124 second tool

Claims (4)

From the outside to the inside, a plurality of layers each different from an adjacent layer are sequentially formed one by one by plastic flow using frictional heat generated by a tool to prepare a precursor, and at least one of the plurality of layers is formed. Forming a metal layer containing a foaming agent, and forming at least one layer as a metal layer containing no foaming agent,
Thereafter, by heating the precursor, a metal is foamed using the foaming agent of the precursor to form a porous metal layer from the metal layer containing the foaming agent, and the foaming agent is contained. A method for manufacturing a pipe having a porous metal layer, comprising a step of forming a metal pipe from a metal layer that is not provided.   Producing the precursor in which at least one layer from the outermost of the plurality of layers is a metal layer containing the foaming agent, and a layer inside the metal layer containing the foaming agent is a metal layer not containing the foaming agent. The method for manufacturing a pipe having a porous metal layer according to claim 1, wherein the porous metal layer is formed outside the metal pipe by heating the precursor.   One or more layers from the outermost of the plurality of layers are metal layers not containing the foaming agent, and the precursor is a metal layer containing the foaming agent, the inner layer of the metal layer not containing the foaming agent. The method for manufacturing a pipe having a porous metal layer according to claim 1, wherein the porous metal layer is formed inside the metal pipe by manufacturing and heating the precursor.   The method for manufacturing a pipe having a porous metal layer according to claim 1, wherein at least one layer of the layers to be the metal pipe or the porous metal layer is formed as a configuration having a plurality of portions each having a different material. .

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