JP2020069481A - Method for producing sprue spreader and method for producing laminating die - Google Patents

Abstract

To obtain a diffusion joining method free from the generation of defects.SOLUTION: Treatments including: a step where a steel (St) and copper or a copper alloy (Cu) before joining are arranged in a pressurization-heating furnace for performing diffusion joining in a combined state, and the temperature in the furnace is stabilized at 600±5°C for about 30 min; a step where the temperature in the furnace is increased for about 14 min at 750±5°C; a step where the pressurization of the inside of the furnace in a state having a stabilized temperature at 750±5°C is started, and the pressurization is gradually performed so that the pressurization force in the furnace reaches 20±0.1 MPa after about 30 min; a step where continuance is performed for about 2 hr in a state where the pressurization force in the furnace reaches 20±0.1 MPa; and a step where, after the passage of about 2 hr, the power source of the temperature in the furnace is made OFF to naturally decrease the temperature, and further, regarding the pressurization force in the furnace, the pressure in the furnace is gradually decreased for about 15 min to make the pressurization force zero are practiced, and also, when the respective treatment are practiced, the degree of vacuum in the furnace is kept to 0.5±0.1 Pa.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for manufacturing a shunt and a method for manufacturing a laminated die.

  It has been conventionally known to provide a shunt (sprue core) in a die casting mold (see, for example, Patent Document 1 below). That is, the die casting mold is provided with a sleeve, and the inside of the sleeve is a plan for advancing through the sleeve to press the molten metal and filling the molten metal into the cavity through the biscuit, runner and gate. A jar tip is provided. The shunt is provided at the position of the biscuit, which is a position opposite to the forward direction of the plunger tip, and the molten metal that has been pushed by the plunger tip and sent through the sleeve collides with the shunt and the shunt causes the molten metal to flow. It is designed to lead to runners and gates. A refrigerant space (refrigerant passage) is formed inside the shunt element, and the shunt element, whose temperature rises due to collision of the molten metal, is cooled by flowing the refrigerant into the refrigerant passage.

  By the way, in this kind of shunt, the refrigerant passage formed by forming a portion including a front portion where the molten metal collides with steel and opening toward a rear portion opposite to the front portion where the molten metal collides. There is one in which the portion surrounding the entire circumference is formed of copper or a copper alloy. At this time, it is known to employ a known dissimilar material bonding technique such as diffusion bonding as a technique for inseparably joining the dissimilar steel and copper or copper alloy (for example, refer to Patent Document 2 below).

Japanese Patent No. 3097515 Japanese Patent No. 5690314

  However, the conventionally known dissimilar material joining technique is not established technically because the joining conditions are often determined by the experience and intuition of the operator. For example, when steel and copper or a copper alloy are diffusion bonded to manufacture a shunt, there is a possibility that cracks may occur during bonding or during quenching after bonding depending on the temperature conditions and pressure conditions during bonding. It was In particular, in the prior art, a phenomenon occurs in which a crack occurs in copper or a copper alloy, and there is room for improvement in the conventionally known dissimilar material bonding technology.

  The present invention has been made in view of the problems existing in the above-mentioned prior art, and when manufacturing a shunt by diffusion bonding steel and copper or a copper alloy, a new defect such as crack does not occur. It is to provide a method for manufacturing a shunt. Further, the present invention has an object of finding conditions for applying the method of the present invention to various methods for manufacturing a laminated die used in a die casting method.

  The present invention will be described below. In addition, in order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are added in parentheses, but the present invention is not limited to the illustrated forms.

  The method of manufacturing the shunt (40) according to the present invention is provided at a position opposite to the forward direction of the plunger tip (31) that moves forward in the sleeve (30) of the mold (1) and presses the molten metal (2). A part of the shunt (40) including a front part (f) with which the molten metal (2) collides is formed of steel (St), and the side opposite to the front part (f) with which the molten metal (2) collides. Is a method for manufacturing a shunt (40) in which a portion surrounding the entire circumference of a refrigerant passage (41) formed by opening toward a rear part (r) of the is formed of copper or a copper alloy (Cu). When the steel (St) and the copper or the copper alloy (Cu) are diffusion-bonded to each other in an inseparable state, the steel (St) and the copper before the joining are performed in a furnace of a pressurizing / heating furnace for performing diffusion bonding. Alternatively, the copper alloy (Cu) is placed in a combined state, and the furnace temperature is 600 ± 5 ° C. Step (I) for stabilizing the temperature in the furnace, then step (II) for increasing the temperature in the furnace by 750 ± 5 ° C. in about 14 minutes, and in a state (III-1) in which the temperature in the furnace is stable at 750 ± 5 ° C. In the step (III), the pressure in the furnace is started (III-2), and after about 30 minutes, the pressure in the furnace is gradually increased to 20 ± 0.1 MPa (III-3). Step (IV) that continues for about 2 hours with the applied pressure being 20 ± 0.1 MPa, and after about 2 hours, turn off the power source of the furnace temperature (V-1) and lower the temperature naturally ( In addition to V-2), the pressure in the furnace includes a step (V-3) in which the pressure in the furnace is gradually reduced to 0 (zero) over about 15 minutes (V-3) step (V). When performing the treatment and each of the above treatments (I to V), maintain the degree of vacuum in the furnace at 0.5 ± 0.1 Pa (VI) It is an feature.

  Moreover, the manufacturing method of the shunt (40) which concerns on this invention WHEREIN: The crystal structure of the said copper or copper alloy (Cu) in the state which the diffusion joining of the said steel (St) and the said copper or copper alloy (Cu) was completed. The size of the crystal may be 100 to 400 μm when observed under a microscope.

  In the method for manufacturing a laminated die according to the present invention, a portion where the molten metal (2) comes into contact and is directly exposed to heat is formed by steel (St), and the heat received by the steel (St) is efficiently removed. A method for producing a laminated mold, wherein a heated and cooled portion is formed of copper or a copper alloy (Cu), and the steel (St) and the copper or the copper alloy (Cu) are diffusion-bonded in an inseparable state. When the diffusion bonding of the steel (St) and the copper or the copper alloy (Cu) is performed in an inseparable state, the steel (St) and the pre-bonded steel are mixed in a furnace of a pressure / heating furnace for diffusion bonding. Step (I) of arranging in a state where copper or copper alloy (Cu) is combined and stabilizing the furnace temperature at 600 ± 5 ° C. for about 30 minutes, and then raising the furnace temperature by 750 ± 5 ° C. in about 14 minutes. The step (II) and the state in which the furnace temperature is stable at 750 ± 5 ° C. (III-1) Step (III) of starting pressurization in the furnace (III-2) and gradually increasing the pressurization in the furnace to 20 ± 0.1 MPa after about 30 minutes (III-3), (IV), which continues for about 2 hours with the applied pressure of 20 ± 0.1 MPa, and after about 2 hours, turn off the power to the furnace temperature (V-1) to naturally lower the temperature Along with (V-2), regarding the pressure in the furnace, the pressure in the furnace is gradually reduced to about 0 (zero) over about 15 minutes (V-3) step (V). It is characterized in that the degree of vacuum in the furnace is maintained at 0.5 ± 0.1 Pa (VI) when the processing including is performed and each of the above processings (I to V) is performed.

  Moreover, the manufacturing method of the laminated die which concerns on this invention WHEREIN: The crystal structure of the said copper or copper alloy (Cu) in the state which the diffusion joining of the said steel (St) and the said copper or copper alloy (Cu) was completed is observed under the microscope. At this time, the crystal size can be 100 to 400 μm.

  According to the present invention, it is possible to provide a new method for manufacturing a shunt, which does not cause defects such as cracks when a shunt is manufactured by diffusion-bonding steel and copper or a copper alloy. In addition, the method of the present invention can be applied to various manufacturing methods of laminated molds used in the die casting method.

It is a sectional view showing a die-casting die provided with a shunt according to the present embodiment, and shows a state before the molten metal is filled. It is sectional drawing which shows the die-casting metal mold | die provided with the shunt according to this embodiment, and shows the state after the molten metal is filled. It is a longitudinal section side view of a shunt according to this embodiment. It is a graph figure for demonstrating the manufacturing method of the shunt according to this embodiment. It is a figure for demonstrating the effect of the manufacturing method of the shunt according to this embodiment, and was manufactured using the manufacturing method of the shunt according to this embodiment shown in FIG. It is the photograph figure which observed the crystal structure of the oxygen free copper (Cu) in a shunt with a microscope, and the partial diagram (b) is an oxygen free copper in a shunt as a comparative example when it deviates from the conditions of the method of this invention. It is a photograph figure which carried out the microscope observation of the crystal structure of (Cu).

  Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. ..

  First, with reference to FIG. 1 and FIG. 2, an overall configuration of a casting facility using a shunt according to the present embodiment will be described. Here, FIG. 1 and FIG. 2 are cross-sectional views showing a die casting mold provided with a shunt according to the present embodiment, in particular, FIG. 1 shows a state before filling the molten metal, and FIG. 2 shows the molten metal. 4 shows the state after the filling. As shown in FIGS. 1 and 2, the shunt 40 is provided in the die casting mold 1 that performs die casting.

  The die casting mold 1 according to the present embodiment includes a fixed mold 10 including a fixed die 12 and a fixed holder 11, and a movable mold 20 including a movable die 22 and a movable holder 21. The fixed die 12 and the movable die 22 define a cavity 1a. A sleeve 30 is provided on the die casting mold 1. The sleeve 30 communicates with the cavity 1a via the biscuit 1b, the runner 1c, and the gate 1d. A plunger tip 31 is provided in the sleeve 30. The plunger tip 31 is capable of advancing and retracting in the sleeve 30 and is configured to move forward and press the molten metal 2 to fill the cavity 2 with the molten metal 2 through the biscuit 1b, the runner 1c and the gate 1d.

  The shunt 40 according to the present embodiment is provided at the position of the biscuit 1b, which is a position facing the forward direction of the plunger chip 31. When the plunger tip 31 is moved forward from the state shown in FIG. 1 to the state shown in FIG. 2, the molten metal 2 pressed by the plunger tip 31 and sent through the sleeve 30 is transferred to the shunt 40. Clash with. The molten metal 2 that collides with the shunt 40 is configured to be guided to the runner 1c and the gate 1d by the shunt 40.

  Next, a more detailed configuration of the shunt 40 according to the present embodiment is shown in FIG. Here, FIG. 3 is a vertical cross-sectional side view of the shunt according to the present embodiment.

  The shunt 40 according to the present embodiment includes a refrigerant passage 41 formed to open toward a rear portion r opposite to a front portion f against which molten metal collides, and a runner portion inevitably cast by a die casting method. And a through-hole 42 in which a push-out pin (not shown) for pushing out is slidably arranged.

  An insert member (not shown) having a coolant supply passage and a coolant discharge passage can be fitted into the coolant passage 41. The coolant passage 41 and the insert member (not shown) are water-tightly sealed by post-processing such as welding, so that the coolant passage 41 formed in the shunt 40 contains coolant such as water and oil. It is distributed and the surrounding area is cooled.

  Further, in the shunt 40 according to the present embodiment, a portion including the front portion f is formed of steel (St), and at least a portion of the portion surrounding the entire circumference of the refrigerant passage 41 and a portion of the through hole 42 are formed. It is made of copper or copper alloy (Cu). In particular, in the present embodiment, SKD61 is adopted for the steel (St), while oxygen-free copper is adopted for the copper or copper alloy (Cu).

  Oxygen-free copper used in this embodiment has a high purity among copper and copper alloys, and has a property of extremely high thermal conductivity. However, since the molten metal 2 directly collides with the shunt 40 and is directly exposed to heat, the shunt 40 must maintain strength while efficiently cooling heat. Therefore, the shunt 40 is manufactured by combining steel with high rigidity (St; SKD61) and copper or copper alloy (Cu; oxygen-free copper) with high thermal conductivity.

  The specific configuration of the shunt 40 according to the present embodiment has been described above. Next, a technique for joining dissimilar materials SKD61 (St) and oxygen-free copper (Cu), which form the shunt 40 according to the present embodiment, will be described with reference to FIGS. 4 and 5. Here, FIG. 4 is a graph for explaining the method for manufacturing the shunt according to the present embodiment. Further, FIG. 5 is a diagram for explaining the effect of the method for manufacturing the shunt according to the present embodiment, and the shunt according to the present embodiment shown in FIG. It is a photograph figure which carried out the microscope observation of the crystal structure of oxygen free copper (Cu) in the shunt produced using the method, and as a comparative example when the diagram (b) deviates from the conditions of the method of the present invention. It is a photograph figure which carried out microscope observation of the crystal structure of oxygen free copper (Cu) in a shunt.

  A method for manufacturing the shunt 40 according to the present embodiment will be described with reference to FIG. In the method for manufacturing the shunt 40 according to the present embodiment, first, diffusion bonding is performed when steel (St; SKD61) and copper or copper alloy (Cu; oxygen-free copper) are diffusion bonded to each other in an inseparable state. The steel (St; SKD61) before joining and the copper or copper alloy (Cu; oxygen-free copper) are placed in the furnace of the pressurizing / heating furnace in a combined state, and diffusion joining is started.

  As the diffusion bonding process step, first, a step (I) of stabilizing the furnace temperature at 600 ± 5 ° C. for about 30 minutes is performed, and thereafter, the furnace temperature is 750 ± 5 ° C. at about 14 minutes. Perform step (II) of raising. Then, pressurization in the furnace was started (III-2) in a state where the temperature in the furnace was stable at 750 ± 5 ° C. (III-1) (III-2), and the pressure in the furnace was 20 ± 0.1 MPa after about 30 minutes. Step (III) of gradually pressurizing (III-3), and further continuing step (IV) for about 2 hours in a state where the pressure in the furnace is 20 ± 0.1 MPa. Run. After about 2 hours, the temperature of the furnace is turned off (V-1) to naturally lower the temperature (V-2), and the pressure in the furnace is gradually increased over about 15 minutes. The step (V) of reducing the pressure in the furnace to 0 (zero) is applied (V-3). Moreover, when performing each process in the above-mentioned process (I-V), the process process (VI) which maintains the degree of vacuum in a furnace at 0.5 +/- 0.1 Pa is performed.

  As described above, by performing the method for manufacturing the shunt 40 according to the present embodiment described with reference to FIG. 4, it has been possible to find a manufacturing method that does not cause a defect such as cracking. The inventors have conducted a verification experiment of the method for manufacturing the shunt 40 according to the present embodiment. For example, as shown in FIG. 5, steel (St; SKD61) and copper or copper alloy (Cu; The crystal structure of copper or a copper alloy (Cu; oxygen-free copper) in a state where the diffusion bonding of (oxygen copper) was completed was observed under a microscope. Here, FIG. 5A shows a crystal structure of oxygen-free copper (Cu) in the shunt 40 manufactured by using the method of manufacturing the shunt 40 according to the present embodiment shown in FIG. It is a photograph figure observed, but when the pressure in the furnace was set to 20 MPa (IV) in a state (III-1) in which the temperature inside the furnace was stabilized at 750 ° C., defects such as cracks were not found at all. I confirmed that it does not occur. At this time, it was also confirmed that the crystal size of copper or copper alloy (Cu; oxygen-free copper) was 100 to 400 μm.

  On the other hand, the diagram (b) in FIG. 5 is a photomicrograph of the crystal structure of oxygen-free copper (Cu) in the shunt as a comparative example, which is produced by deviating from the conditions of the method of the present invention. However, it was confirmed that cracking occurred in oxygen-free copper (Cu) when the pressure inside the furnace was set to 20 MPa while the temperature inside the furnace was stabilized at 900 ° C. At this time, it was confirmed that the crystal size of copper or copper alloy (Cu; oxygen-free copper) was 600 to 1100 μm.

  The result of the verification experiment shown in FIG. 5 shows that the crystal size of copper or copper alloy (Cu; oxygen-free copper) is stably controlled by executing the method for manufacturing the shunt 40 according to the present embodiment. It was also confirmed that the generation of cracks can be preferably prevented by reducing the crystal size. On the other hand, when diffusion bonding is performed without departing from the conditions of the method of the present invention, crystals of oxygen-free copper (Cu) become coarse, and the crystal grain size becomes large, causing a situation in which cracks are likely to occur. It was confirmed that it would end up. From the results of these verification experiments, according to the method of manufacturing the shunt 40 according to the present embodiment, steel (St; SKD61) and copper or copper alloy (Cu; oxygen-free copper) are diffusion-bonded to manufacture a shunt. In doing so, it was confirmed that it is possible to provide a new method for manufacturing a shunt that does not cause a defect such as cracking.

  Regarding the method for manufacturing the shunt 40 according to the present embodiment, each processing step (I to VI) is clarified as shown in FIG. Since it is possible to standardize the work process of diffusion bonding, not the work relying on intuition, it is possible to provide a dissimilar material bonding technology that enables stable production without the occurrence of defects. Furthermore, the method of the present invention thus standardized can be applied to the method of manufacturing various laminated molds used in the die casting method by further verification experiments by the inventors. Has been confirmed. That is, the method of the present invention can be applied to any dissimilar material bonding technique such as a method for manufacturing a laminated die, and is a highly expandable technique.

  Although the preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope described in the above embodiments. Various changes or improvements can be added to the above-described embodiment.

  For example, the shunt 40 shown in the above-described embodiment is merely an example of one embodiment of the shunt to which the method of the present invention can be applied. The form which the shunt can be applied to the method of the present invention can take various modifications.

  Further, in the above-described embodiment, the case where SKD61 is adopted for the steel (St) and the oxygen-free copper is adopted for the copper or the copper alloy (Cu) has been described as an example. The steel, copper, or copper alloy applicable to the above can be applied to various kinds of metals having all kinds and components.

  It is apparent from the scope of the claims that the embodiment added with such changes or improvements can be included in the technical scope of the present invention.

  1 die casting mold, 1a cavity, 1b biscuit, 1c runner, 1d gate, 2 molten metal, 10 fixed mold, 11 fixed holder, 12 fixed die, 20 movable mold, 21 movable holder, 22 movable die, 30 sleeve, 31 Plunger tip, 40 shunt, 41 refrigerant passage, 42 through hole, St steel (SKD61), Cu copper or copper alloy (oxygen-free copper), f front part, r rear part.

Claims (4)

It is a shunt provided at the position opposite to the forward direction of the plunger tip that moves forward in the sleeve of the mold and presses the molten metal, and the portion including the front part where the molten metal collides is formed of steel, and the molten metal collides. A method of manufacturing a shunt, wherein a portion surrounding the entire circumference of the refrigerant passage formed by opening toward a rear portion on the opposite side to the front portion is formed of copper or a copper alloy,
When diffusion-bonding the steel and the copper or copper alloy in an inseparable state, the steel and the copper or copper alloy before the bonding are arranged in a combined state in a furnace of a pressure / heating furnace for performing diffusion bonding. Then
A step of stabilizing the furnace temperature at 600 ± 5 ° C. for about 30 minutes,
After that, a step of increasing the temperature in the furnace by 750 ± 5 ° C. in about 14 minutes,
A step of starting pressurization in the furnace at a temperature of 750 ± 5 ° C. in a stable state and gradually increasing the pressure in the furnace to 20 ± 0.1 MPa after about 30 minutes;
A step of continuing for about 2 hours with the pressure in the furnace being 20 ± 0.1 MPa;
After about 2 hours, the power of the furnace temperature is turned off to naturally lower the temperature, and the pressure in the furnace is gradually reduced over about 15 minutes by reducing the pressure to 0 (zero). ) Process,
A method for producing a shunt, characterized in that the vacuum degree in the furnace is maintained at 0.5 ± 0.1 Pa when a process including the above is performed and each of the above processes is performed. The method for manufacturing a shunt according to claim 1,
When the crystal structure of the copper or the copper alloy in a state where the diffusion bonding of the steel and the copper or the copper alloy is completed is observed with a microscope, the size of the crystal is 100 to 400 μm. Method. The portion where the molten metal comes into contact and is directly exposed to heat is formed by steel, and the portion that efficiently removes and cools the heat received by the steel is formed by copper or a copper alloy, and the steel and the copper or copper. A method of manufacturing a laminated mold in which an alloy is diffusion-bonded in an inseparable state,
When diffusion-bonding the steel and the copper or copper alloy in an inseparable state, the steel and the copper or copper alloy before the bonding are arranged in a combined state in a furnace of a pressure / heating furnace for performing diffusion bonding. Then
A step of stabilizing the furnace temperature at 600 ± 5 ° C. for about 30 minutes,
After that, a step of increasing the temperature in the furnace by 750 ± 5 ° C. in about 14 minutes,
A step of starting pressurization in the furnace at a temperature of 750 ± 5 ° C. in a stable state and gradually increasing the pressure in the furnace to 20 ± 0.1 MPa after about 30 minutes;
A step of continuing for about 2 hours with the pressure in the furnace being 20 ± 0.1 MPa;
After about 2 hours, the power of the furnace temperature is turned off to naturally lower the temperature, and the pressure in the furnace is gradually reduced over about 15 minutes by reducing the pressure to 0 (zero). ) Process,
A method for manufacturing a laminated die, which comprises: performing a process including, and maintaining the degree of vacuum in the furnace at 0.5 ± 0.1 Pa when performing each of the above processes. The method for manufacturing a laminated die according to claim 3,
When the crystal structure of the copper or the copper alloy in a state where the diffusion bonding of the steel and the copper or the copper alloy is completed is observed with a microscope, the crystal size is 100 to 400 μm. Production method.