JP2013144315A - Method for manufacturing joined body, joined body and metal product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a joined body, which can manufacture a joined body that is hardly breakable even when the joined body is used under a condition where a large temperature difference is generated between a first metal member and a second metal member.SOLUTION: The method for manufacturing the joined body includes a joined body forming step of joining the first metal member 12, the second metal member 14 and a third metal member 16 to one another to form the joined body while the third metal member 16 is interposed between the first metal member 12 and the second metal member 14. The joined body forming step includes: a solid phase joining step of interposing the third metal member 16 in which longitudinal elastic modulus and hardness are relatively low, between the first metal member 12 and the second metal member 14, and then solid-state welding the metal members to one another; and a hardness transition region forming step of heating the metal members so that a first hardness transition region 13 is formed in the vicinity of a junction plane of the first metal member 12 and the third metal member 16 and also a second hardness transition region 15 is formed in the vicinity of a junction plane of the second metal member 14 and the third metal member 16.

Description

  The present invention relates to a method for manufacturing a joined body, a joined body, and a metal product.

FIG. 10 is a flowchart shown for explaining a conventional method of manufacturing a joined body.
FIG. 11 is a diagram for explaining a conventional method of manufacturing a joined body. FIG. 11A is a diagram for explaining the metal member preparation step S91, and FIGS. 11B and 11C are diagrams for explaining the joined body forming step S92.

  Conventionally, a manufacturing method of a joined body which joins a plurality of metal members and manufactures a joined body is known (for example, refer to patent documents 1). The conventional method for manufacturing a joined body is a method particularly suitable for producing a joined body by joining steel members containing Cr. Specifically, as shown in FIGS. A metal member preparation step S91 for preparing a first metal member 92 made of the above metal material and a second metal member 94 made of the second metal material, and joining the first metal member 92 and the second metal member 94 together. A joined body forming step S92 for forming a joined body in this order, and the joined body forming step S92 includes a first metal member 92 and a second metal member 92 under a temperature condition in which the first metal member 92 and the second metal member 94 are not melted. A solid-phase bonding step S92a for solid-phase joining the metal member 94, and joining between the two metal members by heating and gradually cooling the joined first metal member 92 and second metal member 94 under predetermined conditions. Strengthening step S94b The including in this order.

  According to the conventional method for manufacturing a joined body, the metal structure transforms voids and a passive layer (a Cr-containing passive layer when the metal member contains Cr) that causes a reduction in the joining force of the joined body. It is possible to dissipate in the process, and as a result, it is possible to manufacture a joined body having a high joining force. In addition, by using a metal member having a concave portion formed on a surface to be joined as at least one metal member of the metal members to be joined, an internal space having a complicated shape (for example, a heat exchange flow channel for flowing a heat exchange medium) It becomes possible to manufacture a joined body having a relatively easy. The joined body produced in this manner can be used for metal products such as various molds, various tools, and various structural members.

International Publication No. 2008/129622

  The joined body manufactured by the above-described method can maintain a sufficiently high joining force when it is used under the condition that a large temperature difference does not occur between the first metal member and the second metal member. However, when the joined body manufactured by the above-described method is used by increasing the hardness by subjecting it to a quenching process, the hardness of the first metal member and the second metal member is increased by the quenching process. Therefore, when the joined body is used under the condition that a large temperature difference is generated between the first metal member and the second metal member, the thermal stress generated due to the temperature difference will limit the bonding force. There is a problem that the joined body may be damaged.

  Therefore, the present invention has been made to solve the above-described problems, and is difficult to break even when a joined body is used under conditions where a large temperature difference occurs between the first metal member and the second metal member. It aims at providing the manufacturing method of the conjugate | zygote which can manufacture a conjugate | zygote. It is another object of the present invention to provide a joined body that is not easily damaged even when the joined body is used under conditions where a large temperature difference occurs between the first metal member and the second metal member. Still another object of the present invention is to provide a metal product using the joined body of the present invention.

[1] The method for manufacturing a joined body of the present invention includes a first metal member made of a first metal material, a second metal member made of a second metal material, the first metal material, and the second metal member. A metal member preparing step of preparing a third metal member made of a third metal material having a lower longitudinal elastic modulus and hardness than any of the metal materials; and between the first metal member and the second metal member, A joined body forming step of joining the first metal member, the second metal member, and the third metal member to form a joined body in the order in which the third metal member is interposed, and the joined body. In the forming step, the first metal member, the second metal member, and the third metal member are not melted with the third metal member interposed between the first metal member and the second metal member. The first metal member, the second metal member and the third metal member under temperature conditions A solid-phase bonding step for solid-phase joining the genus member, and a direction perpendicular to the bonding surface between the first metal member and the third metal member in the vicinity of the bonding surface between the first metal member and the third metal member A first hardness transition region in which the hardness gradually changes from the first metal member to the third metal member along the first metal member, and in the vicinity of the joint surface between the second metal member and the third metal member A temperature at which a second hardness transition region in which the hardness gradually changes from the second metal member to the third metal member along a direction perpendicular to the joint surface between the second metal member and the third metal member is formed. And a hardness transition region forming step in which heat treatment is performed under the above conditions.

  In the joined body produced by the method for producing a joined body of the present invention, the longitudinal elastic modulus is greater between the first metal member and the second metal member than either the first metal material or the second metal material. (Also referred to as Young's modulus) and a condition that a large temperature difference occurs between the first metal member and the second metal member because the third metal member made of the third metal material having low hardness exists. When this is used, the third metal member functions as a buffer material that disperses the thermal stress generated between the first metal member and the second metal member.

  Moreover, in the joined body manufactured by the manufacturing method of the joined body of the present invention, the first metal member and the third metal member, and the second metal member and the third metal member between the first metal member and the third metal member described above. Since the 1 hardness transition region and the 2nd hardness transition region are respectively present, when the joined body is used under a condition in which a large temperature difference is generated between the first metal member and the second metal member, the first hardness transition region and the second hardness transition region are present. The stress generated between the first metal member and the third metal member and between the second metal member and the third metal member due to the thermal stress generated between the metal member and the second metal member is also the first. It will be dispersed in the hardness transition region and the second hardness transition region.

  As a result, according to the method for manufacturing a joined body of the present invention, the thermal stress generated between the first metal member and the second metal member causes the first hardness transition region, the third metal member, and the second hardness transition. Even when the joined body is used under the condition that a large temperature difference occurs between the first metal member and the second metal member because the stress of the region is effectively dispersed, it is dispersed. It becomes possible to manufacture a bonded body that is difficult to perform.

  Further, according to the method for manufacturing a joined body of the present invention, it is possible to dissipate voids and passive layers existing on the joint surface of the metal member while performing the hardness transition region forming process during the joined body forming process. Therefore, as in the case of the conventional method for manufacturing a joined body, it is possible to produce a joined body having a high joining force.

  Further, according to the method for manufacturing a joined body of the present invention, a metal member having a concave portion formed on a surface to be joined is used as at least one metal member to be joined. As in the case of, it is possible to relatively easily manufacture a joined body having an internal space with a complicated shape.

  In addition, the manufacturing method of the joined body of this invention is applicable also when manufacturing the joined body of the structure where the metal member of four or more layers was joined. In this case, if attention is paid to three layers satisfying the conditions of the present invention among the four or more layers, the method for manufacturing a joined body of the present invention is carried out.

  The third metal material is preferably made of a metal material that does not easily increase in hardness by heat treatment (for example, quenching) for increasing the hardness of the first metal member and the second metal member. In this case, even when heat treatment is performed to increase the hardness of the entire bonded body, the hardness is not so high in the portion where the third metal member is present (that is, the longitudinal elastic modulus is high). As a result, the third metal member can sufficiently function as a cushioning material.

[2] In the method for manufacturing a joined body according to the present invention, the first hardness transition region has a thickness of 50 μm or more along a direction perpendicular to the joining surface between the first metal member and the third metal member. Preferably, the second hardness transition region has a thickness of 50 μm or more along a direction perpendicular to a joint surface between the second metal member and the third metal member.

  By adopting such a method, sufficient thicknesses of the first hardness transition region and the second hardness transition region are ensured, and the first metal is generated by the thermal stress generated between the first metal member and the second metal member. The stress generated between the member and the third metal member and between the second metal member and the third metal member can be sufficiently dispersed in the first hardness transition region and the second hardness transition region.

From the above viewpoint, the first hardness transition region has a thickness of 100 μm or more along the direction perpendicular to the joint surface between the first metal member and the third metal member, and the second hardness transition region is the first hardness transition region. More preferably, the second metal member has a thickness of 100 μm or more along a direction perpendicular to the joint surface between the third metal member and the first hardness transition region is a joint surface between the first metal member and the third metal member. The second hardness transition region has a thickness of 200 μm or more along the direction perpendicular to the joint surface between the second metal member and the third metal member. Is even more preferable.
Further, from the viewpoint of further increasing the mechanical strength of the entire joined body, the thickness of the first hardness transition region is 5 mm or less along the direction perpendicular to the joining surface of the first metal member and the third metal member. It is preferable that the second hardness transition region has a thickness of 5 mm or less along a direction perpendicular to the joint surface between the second metal member and the third metal member.

[3] In the manufacturing method of the joined body of the present invention, in the hardness transition region forming step, the first metal transition region and the second hardness transition region in the third metal member, It is preferable that the heat treatment is performed under a condition in which a hardness steady region in which the hardness is in a steady state remains along a direction from the first hardness transition region to the second hardness transition region.

  By setting it as such a method, since the area | region (area | region as the 3rd metal member as it is) with a comparatively low longitudinal elastic modulus remains, it becomes possible to fully exhibit the function as a buffering material to the 3rd metal member. .

[4] In the method for manufacturing a joined body according to the present invention, it is preferable that the hardness steady region has a thickness of 30 μm or more along a direction from the first hardness transition region to the second hardness transition region.

  By setting it as such a method, since the area | region (area | region as the 3rd metal member as it is) where a longitudinal elastic modulus is comparatively low remains sufficiently, it can make the 3rd metal member fully exhibit the function as a buffering material. It becomes possible.

From the above viewpoint, it is more preferable that the hardness steady region has a thickness of 60 μm or more along the direction from the first hardness transition region to the second hardness transition region, and has a thickness of 100 μm or more. Even more preferred.
Further, from the viewpoint of further increasing the mechanical strength of the entire bonded body, it is preferable that the steady hardness region has a thickness of 3 mm or less along the direction from the first hardness transition region to the second hardness transition region.

[5] In the method for manufacturing a joined body according to the present invention, the thickness of the third metal member is preferably in the range of 0.3 mm to 10.0 mm.

  By adopting such a method, it becomes possible to make the thickness of the third metal member sufficient as a cushioning material, and it is possible to produce a joined body having a sufficiently high form stability as a whole. Become.

  In the present invention, the minimum thickness of the third metal member is set within the range of 0.3 mm to 10.0 mm because, when the thickness is smaller than 0.3 mm, the third metal member is the second metal member after solid-phase bonding. This is because it may be absorbed by the first metal member and the second metal member, and it may be difficult to make the thickness of the third metal member sufficient as a buffer material, and the thickness is greater than 10.0 mm. This is because it may be difficult to produce a joined body having sufficiently high form stability as the whole joined body. From this viewpoint, it is more preferable that the minimum thickness of the third metal member is in the range of 0.5 mm to 5.0 mm.

  In addition, the thickness of the 3rd metal member described in said [5] is a thing at the time of a metal member preparation process.

[6] In the method for manufacturing a joined body according to the present invention, after the joined body forming step, at least a portion of the portion where the third metal member is exposed on the surface of the joined body (hereinafter referred to as an exposed portion). While melting the portion where the first metal member, the second metal member, and the third metal member are exposed on the surface of the joined body, the fourth metal member is melted with respect to a part. A coating step of covering, in the coating step, in the vicinity of a boundary surface between the fourth metal member and the third metal member, along a direction from the fourth metal member toward the third metal member. A third hardness transition region in which the hardness gradually changes from the fourth metal member to the third metal member is formed, and the fourth hardness is formed in the vicinity of the boundary surface between the fourth metal member and the first hardness transition region. The first hardness transition from a metal member A fourth hardness transition region is formed in which the hardness gradually changes from the fourth metal member to the first hardness transition region along a direction toward the region, and a boundary between the fourth metal member and the second hardness transition region A fifth hardness transition region in which the hardness gradually changes from the fourth metal member to the second hardness transition region along the direction from the fourth metal member to the second hardness transition region is formed in the vicinity of the surface. It is preferable to coat the fourth metal member under the following conditions.

  By setting it as such a method, in order to coat | cover a 4th metal member on the conditions in which the 3rd hardness transition area | region is formed in the vicinity of the interface of a 4th metal member and a 3rd metal member, The stress generated between the fourth metal member and the third metal member due to the thermal stress generated between the second metal member and the third metal member can be dispersed in the third hardness transition region.

  Further, according to the method [6], the first metal member and the second metal are coated in the covering step in order to cover the fourth metal member under the condition that the fourth hardness transition region and the fifth hardness transition region are formed. Stresses generated between the first metal member and the third metal member and between the second metal member and the third metal member due to the thermal stress generated between the member and the second metal member are the fourth hardness transition region and the fifth hardness. It is possible to be distributed even in the transition region.

  When the first metal member and the fourth metal member are made of different metal materials, the hardness gradually increases from the fourth metal member to the first metal member along the direction from the fourth metal member to the first metal member. It is preferable to coat the fourth metal member under the condition that the sixth hardness transition region that changes to is formed. When the second metal member and the fourth metal member are made of different metal materials, the hardness gradually increases from the fourth metal member to the second metal member along the direction from the fourth metal member to the second metal member. It is preferable to coat the fourth metal member under the condition that the seventh hardness transition region that changes to is formed.

  In the case where the first metal member and the fourth metal member are made of the same metal material, the fourth metal member is mounted under such a condition that a clear boundary surface does not remain between the first metal member and the fourth metal member. It is preferable to coat. Further, when the second metal member and the fourth metal member are made of the same metal material, the fourth metal is used under such a condition that a clear boundary surface does not remain between the second metal member and the fourth metal member. It is preferable to coat the member.

  In the manufacturing method of the joined_body | zygote of this invention, it is preferable to further include the smoothing process of smoothing the part which coat | covered the 4th metal member at the coating process after the coating process. By setting it as such a method, it becomes possible to manufacture a joined body with a smooth surface.

[7] In the method for manufacturing a joined body according to the present invention, the fourth metal member is preferably made of a fourth metal material having a hardness higher than that of the third metal material.

  In general, a metal material having a low longitudinal elastic modulus tends to have a low hardness, and when the third metal member is exposed in the manufactured joined body, the third metal member portion becomes the first metal member portion and It is conceivable that the second metal member is worn earlier than the portion of the second metal member.

  On the other hand, according to the method [7], the third metal member is covered with the fourth metal member made of the fourth metal material having a hardness higher than that of the third metal material. It becomes possible to manufacture a joined body capable of preventing the portion from being worn out earlier than the portion of the first metal member and the portion of the second metal member.

[8] In the method for manufacturing a joined body according to the present invention, the surface of the joined body is partially provided so as to include at least a part of the exposed portion between the joined body forming step and the covering step. It is preferable to further include a surface cutting step for scraping, and in the covering step, it is preferable to cover the fourth metal member so that a portion cut off in the surface cutting step is filled with the fourth metal member.

  By setting it as such a method, since the surface containing a 3rd metal member becomes lower than the surrounding surface, it becomes possible to coat | cover a 4th metal member easily in a coating process.

  In addition, according to the method [8] above, it is possible to scrape off the joint surface of the surface that may have lower joint strength than the internal joint surface, and to improve the mechanical strength of the entire joined body to be manufactured. It becomes.

  The depth dimension for scraping the surface in the surface cutting step can be any dimension depending on the joined body to be manufactured, but is larger than the thickness dimension of the third metal member (for example, the third metal member). 2 to 6 times the thickness dimension).

[9] Preferably, the method for manufacturing a joined body of the present invention further includes a heat treatment step of performing a heat treatment on the joined body after the covering step in order to relieve stress accumulated in the joined body.

  By setting it as such a method, it becomes possible to relieve | moderate the stress accumulate | stored in the conjugate | zygote and to raise the joining force as the whole conjugate | zygote.

  Further, according to the method [9], it is possible to enlarge the range of each hardness transition region by the heat treatment, and to further disperse the stress generated between the metal members.

  An example of the heat treatment as described above is heat treatment including annealing. In addition, when it is desired to obtain high hardness as the whole joined body to be manufactured, quenching or the like may be performed after annealing.

[10] The joined body of the present invention includes a first metal member made of a first metal material, a second metal member made of a second metal material, and the first metal member and the second metal member. And a third metal member made of a third metal material having a longitudinal elastic modulus and hardness lower than those of the first metal material and the second metal material, wherein the third metal member is the first metal material. A joined body having a structure solid-phase joined to a metal member and the second metal member, wherein the first metal member and the first metal member are disposed in the vicinity of a joint surface between the first metal member and the third metal member. A first hardness transition region in which the hardness gradually changes from the first metal member to the third metal member along a direction perpendicular to the joint surface with the three metal members, and the second metal member and the third metal member In the vicinity of the joint surface with the third metal member, the second metal member and the third metal member The second hardness transition region gradually changing in hardness from the second metal member along a direction perpendicular to the mating face toward the third metal member is present, characterized in.

  In the joined body of the present invention, between the first metal member and the second metal member, the longitudinal elastic modulus (also referred to as Young's modulus) and hardness are higher than both of the first metal material and the second metal material. Since there is a third metal member made of a third metal material having a low level, the third metal member is used when this is used under the condition that a large temperature difference occurs between the first metal member and the second metal member. However, it comes to act as a buffer material that disperses the thermal stress generated between the first metal member and the second metal member.

  In the joined body of the present invention, the first hardness transition region and the second hardness transition described above are provided between the first metal member and the third metal member and between the second metal member and the third metal member. Since each region exists, it occurs between the first metal member and the second metal member when the joined body is used under the condition that a large temperature difference occurs between the first metal member and the second metal member. The stress generated between the first metal member and the third metal member and between the second metal member and the third metal member due to the thermal stress is also dispersed in the first hardness transition region and the second hardness transition region. The Rukoto.

  As a result, according to the joined body of the present invention, the thermal stress generated between the first metal member and the second metal member causes the stress in the first hardness transition region, the third metal member, and the second hardness transition region. Since it is effectively dispersed by the function of dispersing, it is possible to make it difficult to break even when used under conditions where a large temperature difference occurs between the first metal member and the second metal member. Become.

  In addition, according to the joined body of the present invention, the metal member having a concave portion formed on the surface to be joined is used as at least one of the metal members to be joined, thereby having an internal space with a complicated shape. However, it becomes a joined body that can be manufactured relatively easily.

  The joined body of the present invention can also be applied to a joined body having a structure in which four or more metal members are joined. In this case, if attention is paid to three layers satisfying the conditions of the present invention among the four or more layers, the bonded body of the present invention is obtained.

  The third metal material is preferably made of a metal material that does not easily increase in hardness by heat treatment for increasing the hardness of the first metal member and the second metal member. In this case, even when heat treatment is performed to increase the hardness of the entire bonded body, the hardness is not so high in the portion where the third metal member is present (that is, the longitudinal elastic modulus is high). As a result, the third metal member can sufficiently function as a cushioning material.

[11] The joined body of the present invention further includes a fourth metal member made of a fourth metal material having a hardness higher than that of the third metal material, and the fourth metal member is formed of the third metal member. The fourth metal member has a structure that covers at least a part thereof, and is disposed in a vicinity of a boundary surface between the fourth metal member and the third metal member along a direction from the fourth metal member toward the third metal member. There is a third hardness transition region in which the hardness gradually changes from the metal member to the third metal member, and from the fourth metal member in the vicinity of the boundary surface between the fourth metal member and the first hardness transition region. There is a fourth hardness transition region in which the hardness gradually changes from the fourth metal member to the first hardness transition region along a direction toward the first hardness transition region, and the fourth metal member and the second hardness In the vicinity of the boundary surface with the transition region, the first It is preferred that there is a fifth hardness transition region gradually changing in hardness toward said fourth metal member from said second hardness transition region along a direction toward the second hardness transition area from the metal member.

  With such a configuration, the third hardness transition region exists in the vicinity of the boundary surface between the fourth metal member and the third metal member, and thus occurs between the first metal member and the second metal member. The stress generated between the fourth metal member and the third metal member due to the thermal stress can be dispersed in the third hardness transition region.

  In addition, according to the configuration of [11] above, since the fourth hardness transition region and the fifth hardness transition region as described above exist, due to the thermal stress generated between the first metal member and the second metal member. The stress generated between the first metal member and the third metal member and between the second metal member and the third metal member is distributed also in the fourth hardness transition region and the fifth hardness transition region. It becomes possible.

  When the first metal member and the fourth metal member are made of different metal materials, the hardness gradually increases from the fourth metal member to the first metal member along the direction from the fourth metal member to the first metal member. It is preferable that there is a sixth hardness transition region that changes to. When the second metal member and the fourth metal member are made of different metal materials, the hardness gradually increases from the fourth metal member to the second metal member along the direction from the fourth metal member to the second metal member. It is preferable that a seventh hardness transition region that changes to

  When the first metal member and the fourth metal member are made of the same metal material, it is preferable that the first metal member and the fourth metal member are joined so that no clear boundary surface remains between them. . Further, when the second metal member and the fourth metal member are made of the same metal material, the second metal member and the fourth metal member are joined so that no clear boundary surface remains between the second metal member and the fourth metal member. Is preferred.

[12] A metal product of the present invention is manufactured using the joined body according to the above [10] or [11].

  According to the metal product of the present invention, the joined body of the present invention that can be hardly damaged even when used under conditions where a large temperature difference occurs between the first metal member and the second metal member. Therefore, even when used under conditions where a large temperature difference occurs, the metal product is not easily damaged.

3 is a flowchart for explaining a method for manufacturing a joined body according to the first embodiment. FIG. 5 is a view for explaining the manufacturing method of the joined body according to the first embodiment. 3 is a graph shown for explaining a method for manufacturing a joined body according to the first embodiment. It is a figure shown in order to demonstrate the conjugate | zygote 10 which concerns on Embodiment 1. FIG. It is a figure shown in order to demonstrate distribution of hardness in joined object 10 concerning Embodiment 1. FIG. It is the photograph shown in order to demonstrate the conjugate | zygote 10a (the whole is not shown in figure) which concerns on an Example. It is a graph shown in order to demonstrate the conjugate | zygote 10a which concerns on an Example. 6 is a flowchart for explaining a method for manufacturing a joined body according to the second embodiment. It is a figure shown in order to demonstrate the manufacturing method of the conjugate | zygote which concerns on Embodiment 2. FIG. It is a flowchart shown in order to demonstrate the manufacturing method of the conventional conjugate | zygote. It is a figure shown in order to demonstrate the manufacturing method of the conventional conjugate | zygote.

  Hereinafter, a method for manufacturing a joined body, a joined body, and a metal product of the present invention will be described based on the embodiments shown in the drawings.

[Embodiment 1]
FIG. 1 is a flowchart for explaining a method for manufacturing a joined body according to the first embodiment.
FIG. 2 is a view for explaining the method of manufacturing the joined body according to the first embodiment. 2A is a view for explaining the metal member preparation step S1, and FIGS. 2B and 2C are views for explaining the joined body forming step S2. (D) is a figure shown in order to demonstrate surface cutting process S3, FIG.2 (e) is a figure shown in order to demonstrate coating | coating process S4, FIG.2 (f) demonstrates smoothing process S6. FIG. 2A to 2F are schematic views showing a part of the portion that becomes the joined body 10 (see reference numeral B in FIG. 4 to be described later). In FIG. 2, the heat exchange channel 19 is not shown. Furthermore, in FIG. 2, the illustration of the heat treatment step S5 is omitted.
FIG. 3 is a graph shown for explaining the method of manufacturing the joined body according to the first embodiment. In FIG. 3, the horizontal axis indicates time, and the vertical axis indicates temperature.

First, a method for manufacturing a joined body according to Embodiment 1 will be described.
The manufacturing method of the joined body according to Embodiment 1 is a method for producing the joined body 10 (see FIG. 4).

  In the manufacturing method of the joined body according to the first embodiment, the metal member preparation step S1, the joined body forming step S2, the surface cutting step S3, the covering step S4, the heat treatment step S5, and the smoothing step S6 are performed in this order. Including. Hereinafter, each step will be described.

1. Metal member preparation process S1
The metal member preparation step S1 is more than the first metal member 12 made of the first metal material, the second metal member 14 made of the second metal material, and any of the first metal material and the second metal material. This is a step of preparing a third metal member 16 made of a third metal material having a low longitudinal elastic modulus and hardness (see FIG. 2A).

  Each of the first metal material, the second metal material, and the third metal material is made of a steel material containing Cr. More specifically, the first metal material and the second metal material are made of tool steel, and the third metal material is made of stainless steel. In the first embodiment, the first metal material and the second metal material are made of the same metal material. As the tool steel, for example, SKD61 which is hot die steel can be used. As the stainless steel, for example, SUS316L which is an austenitic stainless steel can be used. SUS316L is a metal material whose hardness is not easily increased by heat treatment (for example, quenching) for increasing hardness.

In the embodiment 1, the difference between the thermal expansion coefficient of the thermal expansion coefficient of the first metal material and the third metallic material, for example, of ^{1 × 10 -6 m / K~5 ×} 10 -6 m / K in the range, the difference between the thermal expansion coefficients of the third metal material of the second metallic material is also, for example, a range of ^{1 × 10 -6 m / K~5 ×} 10 -6 m / K Is in. Moreover, the difference between the longitudinal elastic modulus of the first metal material and the longitudinal elastic modulus of the third metal material is, for example, in the range of 10 GPa to 20 GPa, and the longitudinal elastic modulus of the second metal material and the third elastic material The difference from the longitudinal elastic modulus of the metal material is also in the range of 10 GPa to 20 GPa, for example.

Planned joining surfaces of the first metal member 12, the second metal member 14, and the third metal member 16 (the portion where the first metal member 12 and the third metal member 16 face each other, the second metal member 14 and the third metal The arithmetic average roughness in the portion facing the member 16 is, for example, 0.2 μm or less.
The thickness of the 3rd metal member 16 exists in the range of 0.3 mm-10.0 mm, Furthermore, it exists in the range of 0.5 mm-5.0 mm, for example, is 1.0 mm. In addition, in Embodiment 1, each joining plan surface is a plane, and each metal member has flat plate shape (shape which rounded the cylinder).

2. Bonded body forming step S2
The joined body forming step S2 includes the first metal member 12, the second metal member 14, and the third metal member 16 in a state where the third metal member 16 is interposed between the first metal member 12 and the second metal member 14. Are joined to form a joined body (see FIGS. 2B and 2C).

The joined body forming step S2 includes a solid phase joining step S2a and a hardness transition region forming step S2b in this order.
As shown in FIG. 3, the solid-phase bonding step S <b> 2 a includes the first metal member 12 and the second metal with the third metal member 16 interposed between the first metal member 12 and the second metal member 14. A predetermined pressure is applied to the member 14 and the third metal member 16, and the first metal member 12 is subjected to a temperature condition (first temperature T <b> 1) at which the first metal member 12, the second metal member 14, and the third metal member 16 do not melt. In this step, the second metal member 14 and the third metal member 16 are solid-phase bonded. In the first embodiment, the solid-phase bonding step S2a is performed by laminating each metal member, applying a predetermined pressure, heating to the first temperature T1, and then gradually cooling.

  The hardness transition region forming step S <b> 2 b is a first step along a direction perpendicular to the joint surface between the first metal member 12 and the third metal member 16 in the vicinity of the joint surface between the first metal member 12 and the third metal member 16. A first hardness transition region 13 whose hardness gradually changes from the metal member 12 to the third metal member 16 is formed, and the second metal member is formed in the vicinity of the joint surface between the second metal member 14 and the third metal member 16. Under a temperature condition in which a second hardness transition region 15 in which the hardness gradually changes from the second metal member 14 to the third metal member 16 along a direction perpendicular to the joint surface between the first metal member 14 and the third metal member 16 is formed. This is a step of performing a heat treatment.

  In the first embodiment, in the hardness transition region forming step S2b, first, the bonded body is once heated to the fourth temperature T4 in order to release the stress remaining after the solid phase bonding step S2a and make the metal structure uniform. After that, cool rapidly and then slowly cool. Thereafter, the joined body is heated to the second temperature T2, and then the joined body is gradually cooled to the third temperature T3. The first temperature T1, the second temperature T2, the third temperature T3, and the fourth temperature T4 can be appropriately selected depending on the type of metal material constituting the metal member to be solid-phase bonded. For example, it is in the range of 850 ° C. to 1150 ° C., the fourth temperature T4 is in the range of 1000 ° C. to 1150 ° C., for example, and the second temperature T2 is in the range of 800 ° C. to 1150 ° C., for example. The third temperature T3 is, for example, 600 ° C. or lower.

  The first hardness transition region 13 has a thickness of 50 μm or more along the direction perpendicular to the joint surface between the first metal member 12 and the third metal member 16, and more preferably has a thickness of 100 μm or more. More preferably, it has a thickness of 200 μm or more. The second hardness transition region 15 has a thickness of 50 μm or more along the direction perpendicular to the joint surface between the second metal member 14 and the third metal member 16, and more preferably has a thickness of 100 μm or more. More preferably, it has a thickness of 200 μm or more. The first hardness transition region 13 preferably has a thickness of 5 mm or less along a direction perpendicular to the joint surface between the first metal member 12 and the third metal member 16, and the second hardness transition region 15 The thickness of the second metal member 14 and the third metal member 16 is preferably 5 mm or less along the direction perpendicular to the joining surface.

In the hardness transition region forming step S <b> 2 b, the first hardness transition region 13 to the second hardness transition region 15 are in the third metal member 16 and between the first hardness transition region 13 and the second hardness transition region 15. Heat treatment is performed under a condition that a hardness steady region in which the hardness is in a steady state along the direction toward (ie, a portion of the third metal member 16 between the first hardness transition region 13 and the second hardness transition region 15) remains. Apply.
The hardness steady region has a thickness of 30 μm or more along the direction from the first hardness transition region 13 to the second hardness transition region 15, more preferably 60 μm or more, and even more preferably 100 μm. It has the above thickness. The steady hardness region preferably has a thickness of 3 mm or less along the direction from the first hardness transition region 13 to the second hardness transition region 15.

  In the hardness transition region forming step S2b in the first embodiment, the bonded body is once heated to the fourth temperature T4 in order to release the stress remaining after the solid phase bonding step S2a and to make the metal structure uniform. Although it cooled rapidly after that and annealed after that, this invention is not limited to this. When the stress remaining after the solid-phase bonding step is sufficiently small, the step of “cooling the bonded body once to the fourth temperature T4 and then rapidly cooling and then gradually cooling” may not be performed.

3. Surface cutting process S3
The surface cutting step S3 is a step of partially scraping the surface of the joined body so as to include at least a part of a portion where the third metal member 16 is exposed on the surface of the joined body (hereinafter referred to as an exposed portion). (See FIG. 2 (d)).

  In the first embodiment, the cutting process is performed so that a groove-shaped recess having a semicircular cross-sectional shape is formed. The dimension of the depth at which the surface is scraped in the surface cutting step S3 is deeper than the dimension of the thickness of the third metal member 16, and is twice to six times the dimension of the thickness of the third metal member 16.

4). Coating step S4
In the covering step S4, the first metal member 12, the second metal member 14, and the third metal member 16 are melted at least on a part of the exposed portion. In this step, the fourth metal member 20 is coated while being melted (see FIG. 2E). That is, it can be said that the coating step S4 is a step of performing liquid phase bonding.
The fourth metal member 20 is made of a fourth metal material having a hardness higher than that of the third metal material. A 4th metal material consists of tool steel, for example, SKD61 which is hot die steel can be used. In the first embodiment, the fourth metal material, the first metal material, and the second metal material are made of the same metal material.

  In the covering step S4, the third metal member 20 to the third metal member 20 are arranged in the vicinity of the boundary surface between the fourth metal member 20 and the third metal member 16 along the direction from the fourth metal member 20 to the third metal member 16. A third hardness transition region 21 whose hardness gradually changes over the metal member 16 is formed, and the first hardness transition from the fourth metal member 20 to the vicinity of the boundary surface between the fourth metal member 20 and the first hardness transition region 13 is formed. A fourth hardness transition region 23 whose hardness gradually changes from the fourth metal member 20 to the first hardness transition region 13 along the direction toward the region 13 is formed, and the fourth metal member 20, the second hardness transition region 15, The fifth hardness transition region 25 in which the hardness gradually changes from the fourth metal member 20 to the second hardness transition region 15 along the direction from the fourth metal member 20 to the second hardness transition region 15 in the vicinity of the boundary surface. Formed Covering the fourth metal member 20 in matter.

In the first embodiment, the fourth metal member 20 is covered under a condition that no clear boundary surface remains between the first metal member 12 and the fourth metal member 20. Further, the fourth metal member 20 is covered under a condition such that a clear boundary surface does not remain between the second metal member 14 and the fourth metal member 20.
In the coating step S <b> 4, the fourth metal member 20 is covered so that the portion cut out in the surface cutting step S <b> 3 is filled with the fourth metal member 20.

5. Heat treatment step S5
The heat treatment step S5 is a step of performing a heat treatment on the joined body in order to relieve stress accumulated in the joined body. As a heat treatment for relieving the stress accumulated in the joined body, a heat treatment including annealing, which is a well-known method, can be used. In addition, when it is desired to obtain high hardness as a whole joined body to be manufactured, quenching or the like may be performed after annealing.

6). Smoothing step S6
The smoothing step S6 is a step of smoothing the portion covered with the fourth metal member 20 in the covering step S4 (see FIG. 2 (f)). Smoothing can be performed by various methods such as polishing and cutting. The bonded body 10 can be manufactured through the above steps.

Next, the joined body 10 will be described.
FIG. 4 is a view for explaining the joined body 10 according to the first embodiment. 4A is a perspective view of the joined body 10, FIG. 4B is a top view of the joined body 10, and FIG. 4C is a cross-sectional view taken along line AA of FIG. 4B. In FIG. 4B and FIG. 4C, the heat exchange channel 19 that is not directly visible from the viewpoint position is indicated by a dotted line.
FIG. 5 is a view for explaining the distribution of hardness in the joined body 10 according to the first embodiment. In FIG. 5, a portion having a high hardness is illustrated in a dark color, and a portion having a low hardness is illustrated in a light color. Note that the broken line in FIG. 5 roughly represents the bonding surface or boundary surface between the metal members at the time of solid phase bonding or coating, and does not represent the distribution of hardness.

  The joined body 10 is a metal product used as a part of a molding die, and it can be said that the joined body 10 is a metal product according to the first embodiment. The joined body 10 has a heat exchange channel 19 for performing heat exchange by flowing a heat exchange medium therein. Regarding the portion of the heat exchange channel 19 that spans the first metal member 12 and the second metal member 14, the first metal member 12, the second metal member 14, and the third metal member 16 are shaved in advance, and then solidified. It is formed by phase joining. Other portions of the heat exchange channel 19 (for example, a portion passing through the metal member 14) can be formed by drilling using a widely used drilling means (for example, a drill).

  The joined body 10 is located between the first metal member 12 made of the first metal material, the second metal member 14 made of the second metal material, and the first metal member 12 and the second metal member 14. And a third metal member 16 made of a third metal material having a lower modulus of elasticity and hardness than the first metal material and the second metal material, and the first metal member 12, the third metal member 16, and the third metal member 16. This is a joined body having a structure in which two metal members 14 are joined (see FIG. 4 for the whole view and FIG. 5 for the details).

  The joined body 10 is in the vicinity of the joint surface between the first metal member 12 and the third metal member 16 and along the direction perpendicular to the joint surface between the first metal member 12 and the third metal member 16. The first hardness transition region 13 where the hardness gradually changes from the third metal member 16 to the third metal member 16, and the second metal member 14 and the second metal member 14 are in the vicinity of the joint surface between the second metal member 14 and the third metal member 16. There is a second hardness transition region 15 where the hardness gradually changes from the second metal member 14 to the third metal member 16 along the direction perpendicular to the joint surface with the three metal members 16 (see FIG. 5).

  The joined body 10 further includes a fourth metal member 20 made of a fourth metal material having a hardness higher than that of the third metal material, and the fourth metal member 20 covers at least a part of the third metal member 16. And the fourth metal member 20 to the third metal member in the vicinity of the boundary surface between the fourth metal member 20 and the third metal member 16 along the direction from the fourth metal member 20 to the third metal member 16. 16, there is a third hardness transition region 21 in which the hardness gradually changes, and from the fourth metal member 20 to the first hardness transition region 13 in the vicinity of the boundary surface between the fourth metal member 20 and the first hardness transition region 13. There is a fourth hardness transition region 23 in which the hardness gradually changes from the fourth metal member 20 to the first hardness transition region 13 along the direction toward the boundary, and the boundary between the fourth metal member 20 and the second hardness transition region 15 In the vicinity of the surface, from the fourth metal member 20 Fifth hardness transition region 25 the hardness from the fourth metal member 20 toward the second hardness transition region 15 along a direction toward the 2 hardness transition region 15 changes gradually is present.

  In the joined body 10, the first metal member 12 and the fourth metal member 20 are joined so as not to leave a clear boundary surface, and the second metal member 14 and the fourth metal member 20 are joined. It is joined so that there is no clear interface between the two.

  Hereinafter, the manufacturing method of the joined body according to Embodiment 1, the effect of the joined body, and the metal product will be described.

  In the bonded body 10 manufactured by the bonded body manufacturing method according to the first embodiment, between the first metal member 12 and the second metal member 14, either the first metal material or the second metal material is used. Since the third metal member 16 made of the third metal material having a lower longitudinal elastic modulus and hardness than that of the first metal member exists, a large temperature difference is generated between the first metal member and the second metal member. When this is used, the third metal member functions as a cushioning material that disperses the thermal stress generated between the first metal member and the second metal member.

  Moreover, in the joined body 10 manufactured by the manufacturing method of the joined body according to the first embodiment, between the first metal member 12 and the third metal member 16 and between the second metal member 14 and the third metal member 16. Since the first hardness transition region 13 and the second hardness transition region 15 described above are present between the first metal member and the second metal member, the joining is performed under a condition in which a large temperature difference occurs between the first metal member and the second metal member. Between the first metal member and the third metal member and between the second metal member and the third metal member due to the thermal stress generated between the first metal member and the second metal member when the body is used. The stress generated in is also dispersed in the first hardness transition region and the second hardness transition region.

  As a result, according to the method for manufacturing the joined body according to the first embodiment, the thermal stress generated between the first metal member 12 and the second metal member 14 is caused by the first hardness transition region 13 and the third metal member. 16 and the second hardness transition region 15 are effectively dispersed by the action of dispersing the stress, so that the joined body is subjected to a condition in which a large temperature difference occurs between the first metal member and the second metal member. It becomes possible to manufacture a joined body that is difficult to break even when using the above.

  Moreover, according to the manufacturing method of the joined body which concerns on Embodiment 1, the space | gap and passive layer which exist in the joint surface of a metal member are dissipated in implementing hardness transition area | region formation process S2b in joined body formation process S2. Therefore, as in the case of the conventional method for manufacturing a joined body, it becomes possible to produce a joined body having a high joining force.

  Moreover, according to the manufacturing method of the joined body which concerns on Embodiment 1, by using the metal member by which the recessed part was formed in the joining plan surface as at least 1 metal member among the metal members to join, the conventional joined body is used. As in the case of the manufacturing method, it is possible to relatively easily manufacture a joined body having an internal space with a complicated shape.

  In addition, according to the method for manufacturing a joined body according to the first embodiment, the third metal material is a metal whose hardness is not easily increased by heat treatment for increasing the hardness of the first metal member 12 and the second metal member 14. Since it is made of a material, even when heat treatment is performed to increase the hardness of the entire bonded body, the hardness of the portion where the third metal member exists is not so high (that is, the longitudinal elastic modulus). The third metal member can sufficiently function as a cushioning material.

  Further, according to the method for manufacturing the joined body according to the first embodiment, the first hardness transition region 13 has a thickness of 50 μm or more along the direction perpendicular to the joining surface between the first metal member 15 and the third metal member 16. And the second hardness transition region 15 has a thickness of 50 μm or more along the direction perpendicular to the joint surface between the second metal member 14 and the third metal member 16, so that the first hardness transition region and the second hardness transition region 15 The thickness of the hardness transition region is sufficiently ensured, and between the first metal member and the third metal member and between the second metal member and the third metal member due to the thermal stress generated between the first metal member and the second metal member. The stress generated between the metal member and the metal member can be sufficiently dispersed in the first hardness transition region and the second hardness transition region.

  Moreover, according to the manufacturing method of the joined body according to Embodiment 1, since the heat treatment is performed under the condition that the hardness steady region remains in the hardness transition region forming step S2b, the region having a relatively low longitudinal elastic modulus (the third metal member as it is). The region) remains, and the third metal member can sufficiently function as a cushioning material.

  In addition, according to the method for manufacturing a joined body according to the first embodiment, since the hardness steady region has a thickness of 30 μm or more along the direction from the first hardness transition region 13 to the second hardness transition region 15, the longitudinal elasticity A sufficiently low region (region where the third metal member is left as it is) remains sufficiently, and the third metal member can be more sufficiently exerted as a buffer material.

  Moreover, according to the manufacturing method of the joined body which concerns on Embodiment 1, since the thickness of the 3rd metal member 16 exists in the range of 0.3 mm-10.0 mm, the thickness of a 3rd metal member is enough as a buffering material. Therefore, it is possible to manufacture a joined body having a sufficiently high form stability as a whole.

  Moreover, according to the manufacturing method of the joined body according to the first embodiment, the fourth metal member is formed under the condition that the third hardness transition region 21 is formed in the vicinity of the boundary surface between the fourth metal member 20 and the third metal member 16. 20, the stress generated between the fourth metal member and the third metal member due to the thermal stress generated between the first metal member and the second metal member is dispersed in the third hardness transition region. It becomes possible to make it.

  Moreover, according to the manufacturing method of the joined body which concerns on Embodiment 1, in order to coat | cover the 4th metal member 20 on the conditions in which the 4th hardness transition area | region 23 and the 5th hardness transition area | region 25 are formed in coating | covering process S4, The stress generated between the first metal member and the third metal member and between the second metal member and the third metal member due to the thermal stress generated between the first metal member and the second metal member is It is possible to disperse also in the 4 hardness transition region and the fifth hardness transition region.

  Moreover, according to the manufacturing method of the joined body which concerns on Embodiment 1, since the smoothing process S6 which smoothes the part which coat | covered the 4th metal member 20 by covering process S4 is further included, a joined body with a smooth surface is manufactured. It becomes possible to do.

  Moreover, according to the manufacturing method of the joined body which concerns on Embodiment 1, since the 4th metal member 20 consists of a 4th metal material whose hardness is higher than a 3rd metal material, hardness is higher than a 3rd metal material. The third metal member is covered with a fourth metal member made of a high fourth metal material, and the portion of the third metal member is worn earlier than the portion of the first metal member and the portion of the second metal member. Thus, it is possible to manufacture a joined body that can be prevented.

  Moreover, according to the manufacturing method of the joined body which concerns on Embodiment 1, since the surface cutting process S3 which scrapes off the surface of a joined body partially so that at least one part may be included among exposed parts is included, a 3rd metal member is included. The surface becomes lower than the surrounding surfaces, and the fourth metal member can be easily coated in the coating process.

  Moreover, according to the manufacturing method of the joined body which concerns on Embodiment 1, the mechanical strength as the whole joined body manufactured by shaving off the joint surface of the surface which may have a joint strength lower than an internal joining surface is improved. It becomes possible to make it.

  In addition, according to the method for manufacturing a joined body according to the first embodiment, after the covering step S4, the joined body includes the heat treatment step S5 in which heat treatment is performed on the joined body in order to relieve stress accumulated in the joined body. It is possible to relieve the stress accumulated in the joint and increase the joining force of the whole joined body.

  Moreover, according to the manufacturing method of the joined body which concerns on Embodiment 1, it becomes possible to enlarge the range of each hardness transition area | region by heat processing, and to further distribute the stress which generate | occur | produces between each metal member. .

  In the joined body 10 according to Embodiment 1, the longitudinal elastic modulus and hardness are lower between the first metal member 12 and the second metal member 14 than both the first metal material and the second metal material. Since the third metal member 16 made of the third metal material exists, when the third metal member 16 is used under the condition that a large temperature difference occurs between the first metal member and the second metal member, Then, the first metal member and the second metal member function as a buffer material that disperses the thermal stress generated between the first metal member and the second metal member.

  In the joined body 10 according to the first embodiment, the first hardness described above is provided between the first metal member 12 and the third metal member 16 and between the second metal member 14 and the third metal member 16. Since the transition region 13 and the second hardness transition region 15 are present, when the joined body is used under the condition that a large temperature difference is generated between the first metal member and the second metal member, The stress generated between the first metal member and the third metal member and between the second metal member and the third metal member due to the thermal stress generated between the second metal member and the second metal member is also the first hardness transition region. And dispersed in the second hardness transition region.

  As a result, according to the joined body 10 according to the first embodiment, the thermal stress generated between the first metal member 12 and the second metal member 14 is caused by the first hardness transition region 13, the third metal member 16, and the first metal member 12. Since it is effectively dispersed by the action of the 2 hardness transition region 15, it is difficult to break even when used under conditions where a large temperature difference occurs between the first metal member and the second metal member. Is possible.

  Moreover, according to the joined body 10 which concerns on Embodiment 1, as a metal member to which it joins, as a at least 1 metal member among the metal members to join, the internal space of a complicated shape is used by using the metal member by which the recessed part was formed. Even if it has, it becomes a joined body which can be manufactured comparatively easily.

  Further, according to the joined body 10 according to the first embodiment, the third metal material is made of a metal material that does not easily increase in hardness by heat treatment for increasing the hardness of the first metal member 12 and the second metal member 14. Therefore, even when heat treatment for increasing the hardness of the entire bonded body is performed to increase the hardness, the hardness of the portion where the third metal member is present is not so high (that is, the longitudinal elastic modulus is high). As a result, the third metal member can sufficiently function as a cushioning material.

  Further, according to the joined body 10 according to the first embodiment, since the third hardness transition region 21 exists in the vicinity of the boundary surface between the fourth metal member 20 and the third metal member 16, the first metal member and the second metal member 20 The stress generated between the fourth metal member and the third metal member due to the thermal stress generated between the metal member and the metal member can be dispersed in the third hardness transition region.

  Further, according to the joined body 10 according to the first embodiment, since the fourth hardness transition region 23 and the fifth hardness transition region 25 exist, the thermal stress generated between the first metal member and the second metal member is caused. The stress generated between the first metal member and the third metal member and between the second metal member and the third metal member is distributed also in the fourth hardness transition region and the fifth hardness transition region. It becomes possible.

  The metal product according to Embodiment 1 can be made difficult to be damaged even when used under conditions where a large temperature difference occurs between the first metal member 12 and the second metal member 14. Since the joined body 10 is manufactured, the metal product is hardly damaged even when used under conditions where a large temperature difference occurs.

[Example]
FIG. 6 is a photograph shown for explaining the joined body 10a (the whole is not shown) according to the embodiment. 6A is an enlarged optical photograph of the cross section of the joined body 10a, and FIG. 6B is an electron micrograph of the cross section of the joined body 10a. The ranges of the hardness transition regions (first hardness transition region 13a, second hardness transition region 15a, third hardness transition region 21a, fourth hardness transition region 23a, and fifth hardness transition region 25a) shown in FIG. It is not necessarily an exact copy of the actual range.

  FIG. 7 is a graph shown for explaining the joined body 10a according to the example. In the graph of FIG. 7, the vertical axis represents hardness and the horizontal axis represents the number of measurement points. The hardness was measured by the micro Vickers method between the first metal member 12a, the third metal member 16a, and the second metal member 14a at an angle of 60 ° with respect to the joint surface. The interval between measurement points is about 24 μm. In FIG. 7, the hardness value appears to fluctuate in a portion where the hardness should be in a steady state or a portion where the hardness should gradually change. This is because the measurement error by the micro Vickers method appears as it is. Because it is. In FIG. 7, the reference numeral 12a indicates the hardness of the portion made only of the first metal member 12a, the reference numeral 13a indicates the hardness of the first hardness transition region 13a, and the reference numeral 16a indicates the third hardness. The hardness of the portion consisting only of the metal member 16a (that is, the hardness steady region), the reference numeral 15a indicates the hardness of the second hardness transition region 15a, and the reference symbol 14a indicates only the second metal member 14a. It is the hardness of the part which consists of.

  In the examples, the bonded body 10a was manufactured using the same method as the bonded body manufacturing method according to Embodiment 1, and observation with photographs and measurement of hardness were performed. In the embodiment, the first metal member 12a (made of SKD61), the second metal member 14a (made of SKD61), the third metal member 16a (made of SUS316L), and the fourth metal member 20a (SKD61). Was used. Although the original thickness dimension of the third metal member 16a was about 0.7 mm, the third metal member 16a was slightly crushed by the pressure and heat in the solid phase bonding process, so that the final third metal The thickness of the member 16a is about 0.6 mm.

  In the example, the hardness was measured between the first metal member 12a, the third metal member 16a, and the second metal member 14a, but between the fourth metal member 20a and the third metal member 16a, the fourth metal member 20a. Each hardness similar to the state of hardness change in the first hardness transition region 13a and the second hardness transition region 15a shown in FIG. 7 also between the first metal member 12a and between the fourth metal member 20a and the second metal member 14a. It is considered that the state of the hardness change in the transition regions (the third hardness transition region, the fourth hardness transition region, and the fifth hardness transition region) is observed.

  As a result of observation and observation in the examples, it was confirmed that the joined body 10a according to the present invention was manufactured.

  Although the experiment is currently under various conditions, a mold is manufactured from the bonded body manufactured using the bonded body manufacturing method according to the present invention, and the durability is tested by actually performing aluminum die casting. As a result, even if the shot exceeded 100,000 shots, the molding die was not damaged.

[Embodiment 2]
FIG. 8 is a flowchart shown for explaining the manufacturing method of the joined body according to the second embodiment.
FIG. 9 is a view for explaining the method of manufacturing the joined body according to the second embodiment. FIG. 9A is a view for explaining the metal member preparation step S11, and FIGS. 9B and 9C are views for explaining the joined body forming step S12. In addition, each figure of Fig.9 (a)-FIG.9 (c) is a schematic diagram which shows a part of part used as the conjugate | zygote 30 (the whole is not shown).

  The manufacturing method of the joined body according to the second embodiment is basically the same method as the manufacturing method of the joined body according to the first embodiment, but according to the first embodiment in that the process after the surface cutting process is not included. This is different from the method of manufacturing the joined body. That is, the method for manufacturing a joined body according to the second embodiment includes the metal member preparation step S11 and the joined body forming step S12 in this order, as shown in FIGS. The metal member preparation step S11 is basically the same as the metal member preparation step S1 and the joined body forming step S12 in the first embodiment, and the detailed description thereof is omitted.

  In addition, the joined body 30 manufactured by the manufacturing method of the joined body according to the second embodiment does not include the fourth metal member, and the portion made of the third metal member 36 is exposed. When the metal product using the joined body 30 is used for an application (for example, a structural member used for an internal structure) in which the difference in surface hardness is not a problem, the joined product 30 according to the second embodiment is used. Such a configuration is sufficient.

  The method for manufacturing a joined body according to the second embodiment is different from the method for producing a joined body according to the first embodiment in that the process after the surface cutting step is not included, but is similar to the method for producing the joined body according to the first embodiment. Furthermore, the thermal stress generated between the first metal member 32 and the second metal member 34 is effective due to the action of dispersing the stress in the first hardness transition region 33, the third metal member 36, and the second hardness transition region 35. Therefore, even when the joined body is used under the condition that a large temperature difference occurs between the first metal member and the second metal member, it is possible to manufacture a joined body that is not easily damaged. It becomes.

  In addition, since the manufacturing method of the joined body which concerns on Embodiment 2 is the method similar to the manufacturing method of the joined body which concerns on Embodiment 1 except the point after the surface cutting process is not included, it is the joining method which concerns on Embodiment 1. It has the corresponding effect as it is among the effects of the body manufacturing method.

  Although the joined body 30 according to the second embodiment is different from the joined body 10 according to the first embodiment in that the fourth metal member is not provided, the first metal member 32 is similar to the joined body 10 according to the first embodiment. The thermal stress generated between the second metal member 34 and the second hardness transition region 33 is effectively dispersed by the action of dispersing the stress in the first hardness transition region 33, the third metal member 36, and the second hardness transition region 35. Therefore, even when used under conditions where a large temperature difference occurs between the first metal member and the second metal member, it is possible to make it difficult to break.

  In addition, since the joined body 30 according to the second embodiment has the same configuration as the joined body 10 according to the first embodiment except that the fourth metal member is not provided, the effect of the joined body 10 according to the first embodiment is obtained. Of which, it has the relevant effect.

  As mentioned above, although this invention was demonstrated based on said embodiment, this invention is not limited to said embodiment. The present invention can be carried out in various modes without departing from the spirit thereof, and for example, the following modifications are possible.

(1) In the above embodiments, the first metal member and the second metal member made of SKD61, which is hot die steel, are used as the first metal member and the second metal member. However, the present invention is limited to this. Is not to be done. As a 1st metal member and a 2nd metal member, as long as it suits the use of the metal product to manufacture, you may use the 1st metal member and 2nd metal member which consist of various metal materials, for example, hot dies other than SKD61 Steel, tool steel other than hot die steel, steel other than tool steel, metal other than steel, and the like can be used. The same applies to the fourth metal member in the first embodiment.

(2) In the above embodiments, the third metal member made of SUS316L, which is austenitic stainless steel, is used as the third metal member. However, the present invention is not limited to this. As the third metal member, a third metal member made of various metal materials may be used as long as it matches the use of the metal product to be manufactured. For example, stainless steel other than SUS316L, steel other than stainless steel, metal other than steel Etc. can be used.

(3) In each of the above embodiments, the case where the planned joining surface is a plane has been described, but the present invention is not limited to this. As long as the surfaces to be joined can be in close contact with each other, the surfaces to be joined may not be flat (for example, a curved surface shape, a step shape, etc.).

(4) In each said embodiment, although the 1st metal member and 2nd metal member which consist of the same metal material were used as a 1st metal member and a 2nd metal member, this invention is limited to this. is not. As the first metal member and the second metal member, a first metal member and a second metal member made of different metal materials may be used.

(5) In Embodiment 1 described above, the fourth metal member made of the same metal material as the first metal member and the second metal member is used as the fourth metal member, but the present invention is limited to this. is not. As the fourth metal member, a fourth metal member made of a metal material different from the first metal member or the second metal member may be used.

(6) In the first embodiment, the fourth metal member made of the fourth metal material having higher hardness than the third metal material is used as the fourth metal member. However, the present invention is limited to this. It is not a thing. As the fourth metal member, a fourth metal member made of a metal material having the same hardness as the third metal material or lower hardness than the third metal material may be used.

10, 30, 90 ... joined body, 12, 12a, 32, 92 ... first metal member, 13, 13a, 23 ... first hardness transition region, 14, 14a, 34, 94 ... second metal member, 15, 15a , 35 ... second hardness transition region, 16, 16a, 36 ... third metal member, 20, 20a ... fourth metal member, 21, 21a ... third hardness transition region, 23, 23a ... fourth hardness transition region, 25 , 25a ... fifth hardness transition region

Claims (7)

The first metal member made of the first metal material, the second metal member made of the second metal material, and the longitudinal elastic modulus and the hardness are lower than any of the first metal material and the second metal material. A metal member preparation step of preparing a third metal member made of a third metal material;
The joined body is formed by joining the first metal member, the second metal member, and the third metal member with the third metal member interposed between the first metal member and the second metal member. A joined body forming step to be formed in this order,
The joined body forming step includes:
Under a temperature condition in which the first metal member, the second metal member, and the third metal member are not melted with the third metal member interposed between the first metal member and the second metal member. A solid phase bonding step of solid phase bonding the first metal member, the second metal member, and the third metal member;
The third metal from the first metal member along the direction perpendicular to the joint surface between the first metal member and the third metal member in the vicinity of the joint surface between the first metal member and the third metal member. A first hardness transition region in which the hardness gradually changes over the member is formed, and the second metal member and the third metal member are disposed in the vicinity of a joint surface between the second metal member and the third metal member. A hardness transition region forming step of performing heat treatment under a temperature condition in which a second hardness transition region in which the hardness gradually changes from the second metal member to the third metal member along a direction perpendicular to the joining surface is formed. A method for manufacturing a joined body comprising the steps in this order. In the manufacturing method of the joined object according to claim 1,
The first hardness transition region has a thickness of 50 μm or more along a direction perpendicular to a joint surface between the first metal member and the third metal member;
The method for producing a joined body, wherein the second hardness transition region has a thickness of 50 μm or more along a direction perpendicular to a joining surface between the second metal member and the third metal member. In the manufacturing method of the joined object according to claim 2,
In the hardness transition region forming step, the first hardness transition region is changed to the second hardness transition region in the third metal member between the first hardness transition region and the second hardness transition region. A method of manufacturing a joined body, characterized in that a heat treatment is performed under a condition that a hardness steady region in which the hardness is in a steady state remains in a direction toward the left. In the manufacturing method of the joined object according to claim 3,
The method of manufacturing a joined body, wherein the hardness steady region has a thickness of 30 μm or more along a direction from the first hardness transition region to the second hardness transition region. In the manufacturing method of the joined object according to claim 4,
The thickness of the third metal member is in the range of 0.3 mm to 10.0 mm. A first metal member made of a first metal material;
A second metal member made of a second metal material;
A third metal, which is located between the first metal member and the second metal member and is made of a third metal material having a longitudinal elastic modulus and hardness lower than those of the first metal material and the second metal material. With members,
A joined body having a structure in which the third metal member is solid-phase joined to the first metal member and the second metal member;
The third metal from the first metal member along the direction perpendicular to the joint surface between the first metal member and the third metal member in the vicinity of the joint surface between the first metal member and the third metal member. There is a first hardness transition region in which the hardness gradually changes over the member, and the second metal member and the third metal member are in the vicinity of the joint surface between the second metal member and the third metal member. A joined body having a second hardness transition region in which the hardness gradually changes from the second metal member to the third metal member along a direction perpendicular to the joining surface.   A metal product manufactured using the joined body according to claim 6.