JP5745789B2 - Solid phase diffusion bonding method of die casting mold material - Google Patents

Description

  The present invention relates to a method for solid phase diffusion bonding of die casting mold materials.

  A casting method (die casting) for producing a die-cast product by press-fitting molten metal into a die-casting die is known. As a die-cast mold material, for example, SKD61 material of die steel is known. A die-cast mold having a complicated shape is formed by bonding die-cast mold materials to each other, and the bonded die-cast mold material is required to have a bonding strength equivalent to that of the base material.

  As a method for joining metal materials such as die casting mold materials, for example, a pulse current joining method is known. Patent Document 1 discloses a pulse energization joining method in which a member is heated in a state in which the joining surfaces of metal members are abutted, and a temperature increasing / decreasing operation is performed a plurality of times to lower the temperature with a transformation point or a solution treatment temperature interposed therebetween. doing.

  However, an oxide film is present on the surface of a metal material such as a die-cast mold material. Here, for example, when the die casting mold materials are heated and bonded together by the pulse current bonding method of Patent Document 1, the oxide film on the bonding surfaces is gasified and remains between the bonding surfaces when the die casting mold materials are bonded to each other. The gas becomes gas, and the bonding strength of the bonded die-cast mold material decreases.

  On the other hand, it is a bonding method in which members to be bonded are brought into close contact with each other, the atmosphere around the members is controlled to a vacuum, and the temperature of the members is increased while pressing the members. A solid phase diffusion bonding method for bonding by using diffusion is also known.

  However, if a high pressing force is applied while raising the temperature while the bonded surfaces of the die casting molds are in contact with each other by the conventional solid phase diffusion bonding method, plastic deformation occurs on the bonded surfaces, and the bonding strength of the bonded die casting mold materials Decreases.

JP 2005-262244 A

  An object of the present invention is to provide a solid phase diffusion bonding method of a die casting mold material that can increase bonding strength.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, in claim 1, a die-casting die material solid-phase diffusion bonding method in which die-casting die materials are brought into close contact with each other and pressed in the adhering direction while heating the die-casting die materials, and the die-casting die materials are joined together. in a state in which abutted, the atmosphere around the die-casting die material is a vacuum, the die-casting die material is allowed to warm, and after the die-casting die material is heated to a predetermined temperature, the second load the die-casting die material together Pressing with a force and ending when the die-cast mold material reaches the first temperature, and pressing the die-cast mold materials with the second load force while maintaining the die-cast mold material at the first temperature A first step and a second step of pressing the die casting mold materials together with a first load force while lowering the temperature of the die casting mold material and maintaining the temperature at the second temperature after the first step. And the first temperature is higher than the second temperature, and is a temperature at which the oxide film present on the surface of the bonding surface between the die-cast mold materials is gasified, The first load force is greater than the second load force.

  In Claim 2, It is a solid phase diffusion bonding method of the die-casting die material of Claim 1, Comprising: The said die-casting die material is SKD61, Said 1st temperature shall be 1030 degreeC or more and 1050 degrees C or less, and said 2nd temperature Is 620 ° C. or higher and 830 ° C. or lower.

  According to the solid phase diffusion bonding method of the die casting mold material of the present invention, the bonding strength can be increased.

The block diagram which showed the joining equipment for enforcing the solid phase diffusion joining method which is embodiment of this invention. The flowchart which similarly showed the flow of the solid phase diffusion bonding method. Similarly, the graph which showed the time-sequential change of the temperature and pressure in a solid phase diffusion bonding method. The schematic diagram which showed the state change of the initial stage process. The schematic diagram which showed the state change of the joining process. The schematic diagram which showed the state change of the crystallization process.

  The solid phase diffusion bonding method of this embodiment is a method of bonding member A and member B, which are SKD61 materials used as a die casting mold material. In solid phase diffusion bonding, the members A and B to be bonded are brought into close contact with each other, the atmosphere around the members A and B is controlled to a vacuum, and the members A and B are pressed while pressing the members A and B. This is a bonding method that raises the temperature, and is a method of bonding by utilizing diffusion of atoms generated on the bonding surface BF with the bonding surface AF.

With reference to FIG. 1, a bonding facility 10 that performs the solid phase diffusion bonding method of the present embodiment will be described.
The joining facility 10 includes a pressurizing device 20, a heater 30, a support base 40, a control device 50, and a test chamber 60. In the test chamber 60, the pressurizing device 20, the heater 30, and the support base 40 are arranged, and the member A and the member B to be joined between the pressurization device 20 and the support base 40. Is arranged. Specifically, the member A is placed on the support base 40 and the member A is disposed above the member B in a state where the joining surface AF of the member A and the joining surface BF of the member B are abutted. Further, a pressurizing device 20 is disposed above the member A.

  The pressurizing device 20 is a device configured to apply the load force F to the member A so that the joining surface AF of the member A presses the joining surface BF of the member B in the close contact direction. The heater 30 is disposed around (side) the member A and the member B, and raises the temperature of the member A and the member B. The control device 50 is connected to the pressurizing device 20 and the heaters 30 and 30.

  The control device 50 controls the degree of vacuum P around the members A and B by controlling the degree of vacuum P by reducing the pressure in the test chamber 60 using a vacuum device (not shown). The pressing force acting on the joining surface BF of the joining surface AF is adjusted by adjusting the load force F to be applied to the member A, and the members A and B are controlled by controlling the ON / OFF of the heaters 30 and 30. It has a function of adjusting the temperature T.

The flow of the solid phase diffusion bonding method of the present embodiment will be described with reference to FIG.
The die casting die material joining method of the present embodiment includes an initial step S100, a joining step S200, and a crystallization step S300.

  In the initial step S100, under the control of the control device 50, the degree of vacuum P in the test chamber 60 is controlled to the degree of vacuum P0, the temperature of the members A and B is raised by the heater 30, and the members A and B are kept at a predetermined temperature. This is a step of applying a load force F to the member A by the pressurizing device 20 after the temperature is raised to.

In the joining step S200, under the control of the control device 50, the member A and the member B are heated by the heater 30 and maintained at the first temperature T1, and the load force F applied to the member A by the pressurizing device 20 is second. The first step of setting the load force F2 and the second step of setting the load force F applied to the member A to the first load force F1 while the members A and B are set to the second temperature T2 by the heater 30 are alternately performed. It is a process repeated several times.
Here, the first temperature T1 is higher than the second temperature T2, and the first load force F1 is larger than the second load force F2.

  In the crystallization step S300, under the control of the control device 50, the member A and the member B heated by the heater 30 are maintained at the first temperature T1, and the load force F applied to the member A by the pressurizing device 20 is the first. This is a step of allowing a predetermined time to elapse while maintaining the three load forces F3.

With reference to FIG. 3, the time series change of the temperature T and the load force F in the solid phase diffusion bonding method of the present embodiment will be described.
3 shows the temperature T of the members A and B (thick solid line in FIG. 3), the load force F applied by the pressure device 20 to the member A (thick broken line in FIG. 3), and the surroundings of the members A and B The time-series change of the degree of vacuum P of the atmosphere (thick two-dot chain line in FIG. 3) is shown. In addition, about the temperature T, the load force F, and the degree of vacuum P, it is assumed that the temperature T, the load force F, and the degree of vacuum P are higher in the direction of the arrow in the graph of FIG.

  Here, in the present embodiment, the first temperature T1 is set to 1050 ° C. in the range from 1030 ° C. to 1050 ° C. at the temperature before the melting point of the SKD61 material. The second temperature T2 is 750 ° C., which is a range from 620 ° C. to 830 ° C. of the pearlite precipitation temperature (transformation point) of the SKD61 material. The first load force F1 is 50 MPa which is 25 MPa or more and 50 MPa or less. The second load force F2 is 10 MPa which is 10 MPa or less. The third load force F3 is 2 MPa, which is 2 MPa or less.

A time series change of the temperature T and the load force F in the initial step S100 will be described.
First, the atmosphere in the test chamber 60, that is, around the members A and B is controlled to a degree of vacuum P0. The members A and B are heated by the heater 30 in a state where the surroundings of the members A and B are maintained at the degree of vacuum P0. Further, after the temperature of the members A and B is raised to a predetermined temperature by the heater 30, the load force F is applied to the member A by the pressure device 20 until the load force F becomes the second load force F2 (10 MPa). The initial step S100 ends when the members A and B reach the first temperature T1 (1050 ° C.).

A time series change of the temperature T and the load force F in the joining step S200 will be described.
In the initial step S100, the load force F applied to the member A by the pressure device 20 is maintained at the second load force F2 (10 MPa) while the member A and the member B are maintained at the first temperature T1 (1050 ° C.). Is done.

Next, the members A and B are cooled to the second temperature T2 (750 ° C.), and the second temperature T2 (750 ° C.) is maintained. When the temperature decrease of the member A and the member B to the second temperature T2 (750 ° C.) is started, the load force F applied to the member A by the pressurizing device 20 is increased to the first load force F1 (50 MPa), The first load force F1 (50 MPa) is maintained.
After the members A and B are maintained at the second temperature T2 (750 ° C.) for a predetermined time, the temperature is raised again to the first temperature T1 (1050 ° C.), and the first temperature T1 (1050 ° C.) is maintained. Until the temperature of the member A and the member B is raised to the first temperature T1 (1050 ° C.), the load force F applied to the member A is again reduced to the second load force F2 (10 MPa) and maintained.

  That is, the first step in which the temperature of the member A and the member B as described above is the first temperature T1 (1050 ° C.) and the load force F applied to the member A is the second load force F2 (10 MPa). The second step in which the temperature of the member A and the member B is the second temperature T2 (750 ° C.) and the load force F applied to the member A is the first load force F1 (50 MPa) is alternately repeated. It is.

  In the present embodiment, the first temperature T1 (1050 ° C.) and the second load force F2 (10 MPa), the second temperature T2 (750 ° C.) and the first load force F1 (50 MPa). The second step is alternately repeated three times or more. In the bonding step S200, the atmosphere around the members A and B is maintained at the degree of vacuum P0.

A time series change of the temperature T and the load force F in the crystallization step S300 will be described.
The members A and B that have been heated to the first temperature T1 (1050 ° C.) in the joining step S200 are maintained as they are as the first temperature T1 (1050 ° C.). On the other hand, the load force F reduced to the third load force F3 (2 MPa) by the pressure device 20 in the joining step S200 is maintained as the third load force F3 (2 MPa) as it is. In the crystallization step S300, the atmosphere around the members A and B is maintained at the degree of vacuum P0.

The state of the joint surface AF and the joint surface BF in the initial step S100 will be described with reference to FIG.
FIG. 4 shows a part of the state where the joining surface AF of the member A and the joining surface BF of the member B are in close contact with each other.
The oxide film 11 exists on the surfaces of the bonding surface AF and the bonding surface BF before the temperature rise, and a gap 15 is formed between the bonding surface AF of the member A and the bonding surface BF of the member B that are abutted with each other. Is present.

  Here, in the initial step S <b> 100, since the temperature of the member A and the member B is raised by the heater 30, the oxide film 11 is gasified, and the components of the gasified oxide film 11 are discharged into the gap 15. And since the circumference | surroundings of the member A and the member B are maintained by the degree of vacuum P0, the gas component which this oxide film 11 gasified is discharged | emitted from the clearance gap 15 to the exterior of the member A and the member B. At this time, since the load force F by the pressurizing device 20 is not yet applied to the member A, the gas component gasified by the oxide film 11 is easily discharged from the gap 15 to the outside of the member A and the member B. Yes.

Thus, in the initial step S100, the oxide film 11 present on the surfaces of the bonding surface AF and the bonding surface BF is gasified and discharged to the outside of the members A and B.
And after the oxide film 11 is discharged | emitted from the clearance gap 15 to the exterior of the member A and the member B, the 2nd load force F2 (10 Mpa) by the pressurization apparatus 20 is provided to the member A. FIG.
Therefore, when applying the load force F to the member A in the initial step S100, the member A and the member B are at least up to a temperature at which the oxide film 11 existing on the surfaces of the bonding surface AF and the bonding surface BF is gasified. The temperature needs to be raised.

With reference to FIG. 5, the crystal behavior state of the joint between the joint surface AF and the joint surface BF in the joining step S200 will be described.
FIG. 5 shows a part of the state change in which the joining surface AF of the member A and the joining surface BF of the member B are joined to form the interface D.

  In the joining step S200, the temperature of the member A and the member B becomes the first temperature T1 (1050 ° C.), and the load applied to the member A becomes the second load force F2 (10 MPa); The second step in which the temperature of the member B becomes the second temperature T2 (750 ° C.) and the load applied to the member A becomes the first load force F1 (50 MPa) is alternately repeated, so that the joint surface AF At the junction between the junction surface BF and the junction surface BF, the crystal behavior changes as shown in the following stage ST (2-1), stage ST (2-2), and stage ST (2-3).

  In the joining step S200, the member A and the member B are maintained at the first temperature T1 (1050 ° C.) of the member A and the member B, and then the load force F applied to the member A is the load of the member A and the member B. When the load force F applied to the member A is maintained up to the force F2 (10 MPa) and increased to the load force F1 (50 MPa) immediately before the plastic deformation of the member A and the member B, the member A and the member B are in the second state. The temperature is lowered to a temperature T2 (750 ° C.). First, as the stage ST (2-1), the bonding surface AF and the bonding surface BF are softened, the gap 15 starts to be crushed, and the surface is flattened.

  Next, in the stage ST (2-2), as the gap 15 is crushed, the area of the portion where the bonding surface AF and the bonding surface BF are in close contact with each other is increased to become the interface D, and the bonding surface AF and the bonding surface BF are separated. The remaining oxide film 11 begins to diffuse into the members A and B from the bonding surface AF and the bonding surface BF.

  Further, in stage ST (2-3), the adhesion between the joining surface AF and the joining surface BF advances, the diffusion of the oxide film 11 into the members A and B progresses, and the metal of the members A and B is promoted. The base body is exposed to the bonding surface AF and the bonding surface BF, respectively, and becomes an interface D that easily diffuses atoms.

And the 1st process made into 1st temperature T1 (1050 degreeC) and 2nd load force F2 (10 MPa), and the 2nd process made into 2nd temperature T2 (750 degreeC) and 1st load force F1 (50 MPa). Are repeated alternately, that is, by repeatedly applying a temperature change and a pressure change to and from the second temperature T2 (750 ° C.), which is the transformation point, to the joint between the member A and the member B. The state change from stage ST (2-1) to stage ST (2-3) is repeated. That is, the bonding surface AF and the bonding surface BF are flattened, and the oxide film 11 existing on the surfaces of the bonding surface AF and the bonding surface BF is diffused into the members A and B, and the bonding surface AF and the bonding surface BF. Becomes the interface D.

The crystal behavior state in the crystallization step S300 will be described with reference to FIG.
FIG. 6 shows a part of a state change in which crystallization proceeds through the interface D.

  In stage ST (3-1), the metal bases of member A and member B are converged to a cubic structure in which one angle at which atom diffusion proceeds and the arrangement structure of atoms in the crystal is stable becomes 120 degrees. Crystallization begins.

  In stage ST (3-2), stable crystal CrA erodes crystals CrC and CrE and grows as crystal CrG. Further, the crystal CrB erodes the crystal CrD and grows into the crystal CrF. As described above, each crystal grows while passing through the interface D, so that the interface D disappears, and the member A and the member B become the same member.

  Thus, in the crystallization step S300, the bonding surface AF and the bonding surface BF are maintained at the first temperature T1 and the third load force F3, thereby promoting atomic diffusion and crystallization.

By adopting such a configuration, the following effects can be obtained.
That is, the oxide film 11 existing between the bonding surface AF of the member A and the bonding surface BF of the member B is discharged to the outside of the member A and the member B in the initial step S100, and is discharged to the outside of the member A and the member B. The oxide film 11 that has not been discharged is diffused into the members A and B in the joining step S200, whereby the oxide film 11 is completely removed from between the joining surface AF and the joining surface BF, and the member A and the member B are removed. Therefore, the strength equivalent to that of the base material can be obtained when the members A and B are joined.

A member AF joint surface B member BF joint surface D interface S100 initial process S200 joint process S300 crystallization process T1 first temperature T2 second temperature F1 first load force F2 second load force F3 third load force

Claims (2)

It is a solid phase diffusion bonding method for die casting mold materials, in which die casting mold materials are brought into close contact with each other, and the die casting mold materials are pressed in the adhering direction while heating the die casting mold materials,
It abutted the die-casting die material together, the atmosphere around the die-casting die material is a vacuum, the die-casting die material is allowed to warm, and after the die-casting die material is heated to a predetermined temperature, the die casting Pressing the mold materials with a second load force , and an initial process that ends when the die-cast mold material reaches the first temperature ;
A first step of pressing the die-casting die materials with the second load force while maintaining the die-casting die material at a first temperature, and a temperature lowering of the die-casting die material after the first step is maintained at a second temperature. And a joining step that repeats the second step of pressing the die-casting mold members together with the first load force a plurality of times,
Comprising
The first temperature is higher than the second temperature, and is a temperature at which an oxide film existing on the surface of the joint surface between the die casting mold materials is gasified,
The first load force is greater than the second load force.
Solid phase diffusion bonding method for die casting mold materials. A method for solid phase diffusion bonding of a die-casting die material according to claim 1,
The die casting mold material is SKD61,
Said 1st temperature shall be 1030 degreeC or more and 1050 degrees C or less,
The second temperature is 620 ° C. or more and 830 ° C. or less.
Solid phase diffusion bonding method for die casting mold materials.

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