JP2001087840A - Outer flask for die and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an outer flask for die which is favorable to restrain the generation of deformation with fatigue on the holding surface of the die compartmenting a chamber for holding the die, and the manufacturing method thereof. SOLUTION: This outer flask 1 for die is manufactured so that the recessed holding chamber 6 for inserting and holding the die 7 having a forming cavity die surface 70 for forming a formed product is opened on this surface. This outer flask 1 for die consists of an outer flask body 3 and a core plate 4 cast into the outer flask body 3. The core plate 4 is harder than the outer flask body 3, and is provided with a die holding surface 35 abutted on the die block surface 73 at the rear side of the forming cavity die surface 70 of the die 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold outer frame for holding a mold having a molding cavity mold surface for molding a molded product such as a die-cast product or a resin molded product, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, in a molding field such as die casting or injection molding, as shown in FIG.
2, a mold outer frame 100 is provided. Mold outer frame 1
In the case of 00, a mold 200 having a molding cavity mold surface 202 for molding a molded product is inserted into the accommodation chamber 102 as a nesting mold, and is fastened and held by unillustrated mounting bolts. On the bottom side of the accommodation room 102 of the mold outer frame 100, the mold 2
00, a flat mold holding surface 104 is formed. The mold holding surface 104 is applied to a mold back surface 204 facing the molding cavity mold surface 202 of the mold 200.

[0003] When using the mold outer frame 100, a molding material such as a molten metal or a resin is injected into a molding cavity 300 formed by clamping the mold outer frame 100. Thus, a molded product such as a cast product or a resin molded product is formed. After the molding, the mold outer frame 100 is opened, and the molded product is taken out.

[0004]

The above-described mold outer frame 10
At 0, a pressure load such as a mold clamping force and a molding pressure acts on the mold 200 during use. Generally, the mold clamping force and the molding pressure are large. The mold clamping force is, for example, several hundred.
It may be 0 tonf. The molding pressure is large in the case of injection molding, and may be, for example, 600 to 1500 kgf / cm ² .

As described above, a large pressure load is applied to the mold outer frame 10.
When the mold outer frame 100 is used for a long period of time, the mold holding surface 104 that divides the accommodation chamber 102 may be settled. When settling occurs, the mold matching accuracy of the mold outer frame 100 is reduced, the dimensional accuracy of the molded product is reduced, or a molding material such as a molten metal leaks from the mold matching surface during molding. Will occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has a mold outer frame and a mold outer frame which are advantageous for suppressing the occurrence of settling on a mold holding surface which defines a housing chamber for holding a mold. It is an object to provide a manufacturing method.

[0007]

According to the present invention, there is provided a mold outer frame, wherein a concave housing chamber in which a mold having a molding cavity mold surface for molding a molded product is inserted and held is opened on the surface. A frame having an outer frame main body, a mold holding surface to which a mold back surface is cast in the outer frame main body and to which a mold back surface facing a molding cavity mold surface of the mold is applied, and which is harder than the outer frame body. And a core disc.

According to the mold outer frame of the present invention, the mold holding surface of the core disk, which is harder than the outer frame main body, is applied to the mold back surface facing the molding cavity mold surface of the mold. For this reason, when a large pressure load acts on the mold during use of the mold outer frame, the pressure load is received by the hard core.

A method of manufacturing a mold outer frame according to the present invention is a method of manufacturing the above-described mold outer frame, comprising: a mold forming step of forming a fire-resistant mold holding a core plate in a casting cavity. A heating step of heating the mold together with the core disc to a temperature range of 200 to 600 ° C., and a casting step of forming a solidified body by casting the core disc by casting the molten metal into the casting cavity of the heated mold and solidifying the molten metal. And a finishing step of finishing the solidified body to form an outer frame main body and forming a mold outer frame having a core plate harder than the outer frame main body.

According to the method of manufacturing a mold outer frame according to the present invention, the mold is heated to a temperature range of 200 to 600 ° C. together with the core plate. Rapid cooling can be suppressed. As a result, the integrity and bonding strength at the boundary surface between the solidified body that casts and surrounds the core disc and the core disc are increased, and the holding properties of the core disc are improved.

[0011] According to the mold outer frame manufactured by the manufacturing method according to the present invention, when a pressure load acts on the mold held by the mold outer frame during use of the mold outer frame, the mold outer frame is prevented. The pressure load is received by the hard core.

[0012]

According to a preferred embodiment of the present invention,
A configuration in which the projected area of the core disc is larger than the projected area of the mold can be adopted. In this case, even when a large pressure load is applied to the mold held by the mold outer frame when the mold outer frame is used, the pressure load is hard and the core plate has excellent surface pressure strength. , And the pressure load per unit area acting on the mold outer frame from the core plate is reduced by stress dispersion, which is more effective in suppressing settling.

The core board is harder than the outer frame body. Hard means that the average hardness of the core disc is higher than the average hardness of the outer frame body. The average hardness of the base plate is Vickers hardness, and the upper limit is, for example, 350, 400, 450, 50.
0, and the lower limit is, for example, 200, 250,
It can be either 300 or 350. Therefore, the average hardness of the core plate can be about 200 to 500, preferably about 250 to 450, as Vickers hardness. However, it is not limited to this. The load used in measuring the Vickers hardness was 20 kgf.

The average hardness of the outer frame body is Vickers hardness, and the upper limit is, for example, 200, 250, 300, 35.
0, and the lower limit is, for example, 120, 200,
250 or 300. Accordingly, the average hardness of the outer frame body can be about 120 to 350, preferably about 140 to 300, as Vickers hardness. However, it is not limited to this.

In general, when a metal material such as an iron-based material has a high hardness, the tensile strength and the surface pressure strength tend to increase accordingly.

It is preferable that both the outer frame main body and the core board are made of a metal material such as iron. The outer frame body can be formed of cast steel or cast iron. Representative cast irons include spheroidal graphite cast iron and flaky graphite cast iron. As mentioned above, the average hardness of the core
Harder than the average hardness of the outer frame body. In this case, the core disc may be hardened and hardened, may be hardened by carbide formation, or may be an intermetallic compound (for example, an intermetallic compound of Ni and Ti, an intermetallic compound of Ni and Al). May be precipitated and hardened.

The form of hardening of the core disk is not limited to this. If the core is hardened by quenching,
Quenching and tempering can be performed as needed.

The core according to the present invention preferably contains at least one of an alloy element having a high quenchability factor, an alloy element that forms carbide, and an alloy element that precipitates and hardens. As alloying elements having high hardenability multiples, in addition to carbon, S
At least one of i, Cr, Mo, W, and V is included. In this case, the core disk is easily baked, and the hardness of the core disk can be increased, which is effective in suppressing settling. Carbon, Cr, W, Mo, V, N as alloying elements for forming carbides
and at least one kind of b. Examples of the alloy element to be precipitated and hardened include at least one of Cr, Ni, Al, Ti, Be, and Mo.

In the core disk according to the present invention, although the carbon content varies depending on the hardening mode of the core disk, the carbon content of the core disk is one.
When it is set to 00%, the upper limit value of carbon in the weight ratio in the core board is 0.5%, 0.8%, 1.0%, 1.2%,
2.0%, with lower limits of 0.2%, 0.4%,
0.6%. Therefore, the carbon content in the core board is, for example, 0.2 to 2.0%, 0.4 to 1.2% by weight,
It can be 0.4-0.8%. However, it is not limited to these.

The core board according to the present invention can be constructed by cutting a board material into a predetermined size. The base plate can be formed of a high alloy steel such as stainless steel, heat-resistant steel, and tool steel. As stainless steel, martensitic stainless steel, austenitic stainless steel, ferritic stainless steel,
Any of PH stainless steel and maraging stainless steel may be used. As a high alloy steel other than stainless steel,
Tool steels such as tool steels for hot working, high speed steels, and spring steels.

In consideration of the above circumstances, when the core disk is iron-based, the metal structure of the core disk can be composed of at least one of martensite, troostite, sorbite, austenite, and pearlite.

According to the method of the present invention, in the mold forming step,
A refractory mold holding a mandrel in a casting cavity is formed. In this case, the core disc may be incorporated into the mold after the mold is molded, or the mold may be molded while incorporating the core disc.

A sand mold can be used as a mold. In this case, it is possible to use sand hardened with a binder using sand such as silica sand as an aggregate. Considering the temperature in the heating step, the binder is preferably an inorganic binder, particularly an inorganic binder having heat resistance. For example, a water glass binder can be employed. 10 molds without core
When it is 0%, the ratio of the binder can be, for example, 2 to 15% by weight, but is not limited thereto. Note that the mold may be formed of bricks having high fire resistance.

[0024] In the heating step according to the method of the present invention, the mold and the core plate are heated to a temperature range of 200 to 600 ° C. In this case, the entire mold in which the core plate is incorporated may be charged into a heating chamber of a heating furnace and heated, or the mold may be heated by a flame burner or the like. If the heating temperature of the core plate is too low, when the molten metal touches the core plate, the molten metal in that portion is excessively quenched, and the bonding strength between the core plate and the outer frame body is reduced. If the heating temperature of the core disk is too high, oxide scale is generated on the core disk or the core disk is deformed. In consideration of such circumstances, the temperature of the mold is set to 200 to 600C. When the core disc is made of a high alloy steel such as stainless steel, excessive generation of oxide scale is suppressed even when the core disc is heated to a high temperature. Note that the heating step may be performed in an air atmosphere, may be performed in a reduced-pressure atmosphere in order to suppress an oxide scale, or may be performed in a reducing atmosphere.

The heating temperature according to the method of the present invention varies depending on the material of the core plate, the material of the mold, the weight of the molten metal to be cast to form the outer frame body, and the like. 580 ° C, 550 ° C, 520
, 490, 460, 430, 410, 380
° C. As the lower limit, for example, 200
° C, 220 ° C, 250 ° C, 280 ° C, 310 ° C, 340
C, 370 C, 400 C, 430 C, or 460 C. Therefore, the heating temperature is 200 to 600
° C, 220-580 ° C, 250-550 ° C, 300-5
Can be 00 ° C. The heating time is also affected by the size of the core and the outer frame body, the heating temperature, etc., but in general,
It can be about 2 to 12 hours, especially about 3 to 8 hours.

In the casting step according to the present invention, a molten metal is poured into a casting cavity of a mold in a heated state and solidified to form a solidified body in which a core disk is cast. Since the mold is in a heated state, the molten metal runs well, and the contact surface between the mandrel and the solidified body is melt-bonded, so that both can be brought into close contact with each other.

In the finishing step according to the present invention, the solidified body is subjected to finish processing to form a mold outer frame. Thereby, a mold outer frame is formed. The mold outer frame includes an outer frame main body, and a core disc which is cast in the outer frame main body and is harder than the outer frame main body. The core disc is
A mold holding surface is provided to be applied to the back surface of the mold opposite to the mold cavity surface of the mold.

[0028]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a first mold outer frame 1 according to the present embodiment is attached to a die base 2 and constitutes a movable side. The first mold outer frame 1 is a rectangular outer frame body 3 made of cast steel or spheroidal graphite cast iron.
And a core plate 4 formed of a rolled steel material and having a substantially rectangular flat plate shape.

As shown in FIG. 1, the core disc 4 is integrally cast and buried in the outer frame body 3, and both are in close contact with each other. The core disk 4 has a higher average hardness than the outer frame body 3. Therefore, the core disc 4 is harder than the outer frame body 3. The average hardness of the outer frame body 3 is about 150 to 200 in Vickers hardness. The average hardness of the core plate 4 is higher than the hardness of the outer frame body 3 and is 300 to 38 Vickers hardness.
It is about 0.

Since the core disk 4 contains a large amount of alloy elements as described above, the core disk 4 has high hardness even if the cooling rate is slow. Mandrel 4 may be hardened by quench hardening, may be hardened by generation of carbide, or may be hardened by precipitation hardening.

As shown in FIG. 4, a housing chamber 6 having an opening 6a communicating with the outside air is formed in the center of the outer frame body 3. The accommodation room 6 has an inner wall surface 6c machined (cut). The housing chamber 6 is a space in which a mold 7 having a molding cavity mold surface 70 for molding a molded product is inserted and held as an insert mold. As shown in FIG. 5, a flat mold back surface 73 is formed on the side of the mold 7 that faces away from the molding cavity mold surface 70.

As shown in FIG. 4, the periphery of the core plate 4 is cast in the outer frame body 3. The core plate 4 is a mold back surface 7 of the mold 7.
3 is provided with a flat mold holding surface 35.
The mold holding surface 35 is exposed to the accommodation room 6 and forms the bottom surface of the accommodation room 6. The projected area of the mandrel 4 is set larger than the projected area of the mold 7. Therefore, in the plane form, as shown in FIG.
On the four sides, a protruding edge portion 45 that protrudes substantially evenly from the outer side surface 7p of the mold 7 is formed. Oblique sides 45i are formed at the four corners of the protruding edge 45 at the four corners of the mandrel 4. In FIG. 2, the hatched area indicates a molding cavity mold surface 70 for molding a molded product,
Reference numerals 39a and 39b denote flow paths through which the molding material flows.

The size of the core plate 4 is 52 cm × 55 c.
It is about mx 6 cm. The size of the outer frame body 3 is 60 cm
It is about × 71 cm × 34 cm. Note that the size is not limited to this, and can be appropriately changed according to the type of the molded product.

The material of the core plate 4 is martensitic stainless steel, which has high hardness and excellent corrosion resistance such as normal temperature corrosion resistance and high temperature corrosion resistance.

The manufacturing of the first mold outer frame 1 according to the present embodiment is performed as follows. First, in a mold forming step, as shown in FIG. 6, a mold 8 having fire resistance is formed. The mold 8 includes a lower die 81, a middle die 82 placed on the lower die 81, and an upper die 83 placed on the middle die 82. The lower mold 81 includes a lower sand mold 81a formed of sand containing a binder, and a casting frame 81c that holds the lower sand mold 81a. The middle mold 82 includes a middle sand mold 82a formed of sand containing a binder, and a middle casting frame 82c that holds the middle sand mold 82a. The upper mold 83 includes an upper sand mold 83a formed of sand containing a binder, and an upper molding frame 83 holding the upper sand mold 83a.
c.

As shown in FIG. 6, the mold 8 has a sprue cavity 85, a runner cavity 86, a weir cavity 87,
A feeder cavity 88 is formed, and further, a casting cavity 89 for forming a mold outer frame is formed. Since the weir cavity 87 is formed in the boundary area between the lower mold 81 and the middle mold 82, the molten metal is poured into the casting cavity 89 from the bottom side thereof. As shown in FIG. 6, the feeder cavity 88 is located above the outer edge of the core plate 4. Therefore, the weight of the molten metal injected into the feeder cavity 88 can act on the outer edge of the core plate 4.

As shown in FIG. 6, the middle sand mold 82
a on the upper surface of the bulging portion 82k which is a part of
The core disc 4 is held by the plurality of holding rods 90 in a state in which is placed in a horizontal state. Usually, the holding rod 90 may be a bolt. As a result, the core disc 4 is moved to the casting cavity 8 of the mold 8.
9 is held. In this state, as shown in FIG.
The mandrel 4 is in face-to-face contact with a bulging portion 82k that is a part of the middle sand mold 82a of the middle mold 82. Further, as shown in FIG. 6, one surface 4a and the peripheral surface 4c of the core disc 4 are exposed to the casting cavity 89. The outer edge 4e of the other side 4b of the core plate 4 is also exposed to the casting cavity 89.

Next, a heating step is performed. In the heating step, the mold 8 holding the core plate 4 is placed in the heating chamber 8 of the heating furnace 800.
02, and in this state, the mold 8 is
Heat to a predetermined temperature range of 0 to 600 ° C. The heating time varies depending on the heating temperature, for example, about 3 to 8
Can be in time. Thereby, the core disc 4 is heated to a high temperature state together with the mold 8. Note that the heating chamber 802 is in an air atmosphere. Since the mandrel 4 contains a large amount of alloying elements such as Cr having excellent oxidation resistance, the oxide scale in the mandrel 4 can be suppressed.

Next, a casting step is performed. In the pouring step, a high-temperature iron-based molten metal of about 1380 to 1420 ° C. is cast into the casting cavity 89 of the heated mold 8 immediately after being taken out of the heating furnace 800. By solidifying the molten metal in the casting cavity 89, the outer surface of the core plate 4 is cast-in. Thus, an iron-based solidified body M shown in FIG. 3 is formed.
Specifically, as shown in FIG.
, The entire area of the peripheral surface 4c of the mandrel 4, and the outer edge 4e of the one side 4b of the mandrel 4.

Since the outermost surface of the core plate 4 in contact with the iron-based molten metal is melted and re-solidified, the adhesion between the outer frame body 3 and the core plate 4 is improved. Furthermore, since the coagulated body M is subjected to shrinkage due to solidification and shrinkage due to cooling after solidification, these contractions cause the adhesion between the outer frame main body 3 formed of the solidified body M and the core plate 4 to be reduced. Is improving.

In the above casting step, the molten metal can be poured into the casting cavity 89 of the mold 8 while the mold 8 provided with the core plate 4 is held in the heating furnace 800.

According to the present embodiment, the mold is attached to
Since the molten metal is heated to a predetermined temperature range of 00 to 600 ° C., even if the molten metal poured in the casting step comes into contact with the core plate 4, excessively rapid cooling of the molten metal can be suppressed. Thus, cracking of the core plate 4 is prevented. As a result, the integrity and bonding strength at the boundary surface between the solidified body M that casts the core 4 and the core 4 are increased. Welding at the boundary surface between the solidified body M and the core plate 4 or alloying by welding can also be achieved.
In this case, since the bonding strength at the boundary surface between the solidified body M and the core disc 4 is further increased, the ability of the outer frame body 3 formed of the solidified body M to hold the core disc 4 is improved. After the pouring step is completed, the mold 8 is collapsed, and the solidified body M in which the core plate 4 is embedded as shown in FIG. 3 is taken out. In this state, as shown in FIG. 3, most of the central region of one surface 4b of the core board 4 is exposed to the accommodation room 6, and is in a naked state.

Next, a heat treatment step is performed. In the step of heat treatment, the first mold outer frame 1 is charged into a heating furnace (the heating furnace 800 described above or another heating furnace may be used), and The mandrel 4 is heated to a predetermined heat treatment temperature range (for example, 850 to 950 ° C.). Then, the cooling medium (for example, air cooling air, sometimes mist,
Water, oil, etc.) is sprayed onto the first mold outer frame 1 to promote cooling of the core plate 4, thereby cooling the core plate 4 embedded in the first mold outer frame 1 at a predetermined cooling rate. . Thus, heat treatment (quenching or normalizing) is performed on the core disc 4.

In the present embodiment, as can be understood from FIG. 3, although the core disc 4 is embedded in the solidified body M serving as the outer frame body 3, the center area of the one surface 4b of the core disc 4 as described above. Most of them are exposed to the accommodation room 6 and are naked. For this reason, at the time of the above-mentioned heat treatment, a cooling medium (for example, air for air cooling, mist, water, oil, etc. depending on the case) is supplied to the accommodation room 6 and forcedly or naturally applied to the one surface 4 b of the core plate 4. If the contact is made, the cooling speed of the core plate 4 can be increased. Therefore, the heat treatment property (hardenability or normalizing property) of the core disk 4 can be effectively secured, which is advantageous for securing the required hardness of the core disk 4, and the hardness of the core disk 4 can be increased. This is advantageous. The mist is a mist-like cooling medium sprayed with cooling water.

In particular, as can be understood from the comparison between FIGS. 3 and 5, since the one side 4b of the core plate 4 is the side where the mold 7 contacts, increasing the cooling rate on the one side 4b is not possible with the core plate. This is advantageous for suppressing the settling of No. 4.

Depending on the composition of the core plate 4, the cooling medium (for example, air cooling air, sometimes mist, water, oil, etc.) may not be forcibly fed into the storage chamber 6, but may be left alone. 4 may be air-cooled. When burnt cracks or the like occur in the core plate 4, it is preferable to use air, mist, oil, or the like having a lower cooling capacity than water.

In the present embodiment, when the above-mentioned heat treatment is quenching of the core disc 4, tempering processing such as high-temperature tempering or low-temperature tempering is performed on the core disc 4 as necessary. Can also. If tempering is performed on the core disc 4, the toughness of the core disc 4 can be increased while maintaining the required hardness of the core disc 4. In this case, the solidification body M in which the core disc 4 is embedded can be charged into a heating furnace and heated and maintained at a tempering temperature (for example, 500 to 600 ° C. in the case of high-temperature tempering). . If not necessary, the tempering process may not be performed.

It should be noted that even when the core plate 4 having a large content of alloying elements is quenched, the solidified body M having a small content of alloying elements is basically not quenched.

After finishing the heat treatment process as described above, a finishing process is performed next. In the finishing step, finishing is appropriately performed by machining (cutting). Specifically, as can be understood from FIG. 4, a portion of the one surface 4 b of the mandrel 4 that is exposed to the accommodation chamber 6 is Δt-cut by machining (cutting). Thus, a flat and smooth mold holding surface 35 is formed on the core plate 4. Since the mold holding surface 35 is flattened and smoothed by machining (cutting), the adhesion holding property of the mold 7 to the mold back surface 73 is improved. Further, the smooth inner wall surface 6c is formed on the outer frame main body 3 by the above-described machining (cutting).

According to the present embodiment, as shown in FIG. 5, the mold 6 is inserted into the accommodating chamber 6 of the first mold outer frame 1 and the opening 6 is formed.
Insert from a and hold. The mold 7 is connected to the first mold outer frame 1
In the state of being housed and held in the housing room 6, the flat mold back surface 73 of the mold 7 is connected to the flat mold holding surface 35 of the outer frame body 3.
Is assigned to

As can be understood from FIG. 5, in a state in which the mold 7 is housed and held in the housing chamber 6 of the mold outer frame 1, the back side of the first mold outer frame 1 is formed by using a drilling tool such as a drill. Then, the mounting hole 36 is formed. The mounting hole 36 includes a hole 36a penetrating the outer frame main body 3 in the thickness direction, a hole 36b penetrating the mandrel 4 in the thickness direction, and a hole 36c having a female screw portion 37 formed on the back surface of the mold 7. Is formed. Holes 36a, 3
6b and 36c communicate with each other in series. As shown in FIG. 5, the male screw portion 86 on the tip side of the mounting bolt 85 is screwed into the female screw portion 37 so that the mold 7 is detachably fixed to the housing chamber 6 of the outer frame body 3.

When the mounting bolt 85 is loosened, the mold 7 can be removed from the outer frame body 3. The number of mounting bolts 85 can be appropriately selected according to the size of the core plate 1 and the mold 7, and can be, for example, 2 to 30, 5 to 12. However, it is not limited to this.

As shown in FIG. 1, a second mold outer frame 9 which is a counterpart of the first mold outer frame 1 is provided. The second mold outer frame 9 constitutes a fixed side. The second mold outer frame 9 also
It has the same configuration as the first mold outer frame 1 and is manufactured by a similar manufacturing method. That is, the second mold outer frame 9 is connected to the outer frame main body 3.
And a hard mandrel 4 cast in the outer frame body 3.

In use, as shown in FIG. 1, the first mold outer frame 1 and the second mold outer frame 9 are attached to a mold attaching device (not shown) having mold clamping and mold opening functions. . In this state, the die base 2 is provided on the back side of the first mold outer frame 1 on the movable side.
Will be equipped. When the mold mounting device operates in the mold clamping direction,
As shown in FIG. 1, the first mold outer frame 1 and the second mold outer frame 9 are clamped. When the first mold outer frame 1 and the second mold outer frame 9 are clamped, the molding cavity mold surface 7 of the first mold outer frame 1 is closed.
0 and the molding cavity mold surface 70 of the second mold outer frame 9 define a molding cavity 75.

A molten metal of a high-temperature metal as a molding material (material:
Aluminum, temperature: 640-750 ° C.) is injected into the molding cavity 75 at high speed by injection molding. When the mold mounting device is operated in the mold opening direction after the molten metal is solidified, the first mold outer frame 1 and the second mold outer frame 9 are opened, and the molded product is formed by the pushing action of an unillustrated extrusion pin. Taken out.

In use, a pressure load such as a mold clamping force and a molding pressure acts on the mold 7 held by the first mold outer frame 1. When the pressure load acts as described above, the pressure load is received by the hard core 4 via the mold 7. The core plate 4 has high hardness and high surface pressure strength. For this reason, even if the use period is prolonged or the pressure load is large, the mold holding surface 3 that partitions the accommodation chamber 6 that holds the mold 7 is used.
The occurrence of settling in 5 is suppressed.

In particular, in this embodiment, as shown in FIG. 2, since the projected area of the core plate 4 is set to be larger than the projected area of the mold 7, the core receiving the pressure load from the mold 7 is used. The pressure receiving area of the panel 4 is increasing. Therefore, even if the use period is prolonged or the pressure load becomes excessive, occurrence of settling on the mold holding surface 35 of the first mold outer frame 1 is suppressed.

That is, in the present embodiment, as shown in FIG. 2, since the protruding edge portions 45 protruding from the outer surface 7p of the mold 7 are formed on four sides of the core disk 4, the core disk 4 has In order to disperse the acting pressure load, the core disc 4 of the outer frame body 3
And the pressure load on the joint surface 3a can be reduced. Specifically, the pressure load on the joint surface 3a can be reduced to approximately one-half the area ratio. Therefore, even if the use period becomes considerably long,
Alternatively, even if the pressure load is excessive, the mold holding surface 3 may be formed due to the settling of the joint surface 3 a of the outer frame body 3 with the core plate 4.
The occurrence of settling in 5 is further suppressed.

The core plate 4 is made of stainless steel.
Excellent corrosion resistance. Therefore, corrosion on the mold holding surface 35 which is a boundary area between the core plate 4 and the mold 7 can be suppressed. Further, wear caused by corrosion can be suppressed. For example, fretting wear can be prevented.
In particular, even when the cooling water or the release agent enters the mold holding surface 35 which is the boundary area between the mold 7 and the core plate 4, it is possible to suppress the corrosion on the mold holding surface 35. it can. For this reason, in the first mold outer frame 1 and the second mold outer frame 9, it is possible to prevent wear due to corrosion and promotion of settling due to a decrease in surface pressure strength due to corrosion. Mold holding surface 3 of second mold outer frame 9
Similarly, in No. 5, the occurrence of settling is suppressed.

Further, in the present embodiment, when the molten metal to be the solidified body M is cast in the casting step, the mold 8 is previously heated, so that the molten metal to be the solidified body M runs well. . Furthermore, since the core plate 4 is heated to a high temperature state in the casting step, even if the high-temperature molten metal touches the core plate 4, excessive rapid cooling of the molten metal can be suppressed. For this reason, the joining strength in the boundary region between the outer frame body 3 and the core board 4 can be increased. Alloying in the boundary region between the outer frame main body 3 and the core disc 4 can also be expected.

(Test Example) FIG. 7 shows the heating temperature of the mold 8,
The test result which tested about the relationship with the joining strength of the outer frame main body 3 and the core board 4 is shown. This test was performed using a model in which the outer frame main body 3 and the core board 4 were reduced. The main component of the mold 8 is silica sand, the binder is water glass, and the material of the core plate 4 is martensitic stainless steel (SUS420).
J2), and the material of the outer frame body 3 was SCMn3A. The horizontal axis in FIG. 7 indicates the heating temperature of the mold, and the vertical axis in FIG. 7 indicates the bonding strength at the boundary region between the outer frame body 3 and the core plate 4. The joining strength was measured by conducting a tensile test on the above-described model and applying a tensile stress in a direction perpendicular to the boundary surface.

In FIG. 7, the casting strength of the outer frame body 3 is S1.
, And 80% of the casting strength of the outer frame body 3 is shown as S2, and 70% of the casting strength of the outer frame body 3 is shown as S3. As shown in FIG. 7, the heating temperature of the mold 8 is 2
At 00 to 600 ° C., the joining strength was high, and about 70% of the casting strength of the outer frame body 3 was obtained. In particular, when the heating temperature of the mold 8 was 300 to 500 ° C., about 80% of the casting strength of the outer frame body 3 was obtained. Among them, the bonding strength was the highest at 400 ° C.

(Other Embodiment) As shown in FIG.
The recesses 4x and 4y may be formed in the recess. Since the molten metal constituting the outer frame body 3 enters the recesses 4x and 4y and is solidified, the degree of mechanical engagement between the core disc 4 and the outer frame body 3 can be improved.

As shown in FIG. 9, a reinforcing rib 4w can be formed on the surface of the mandrel 4 opposite to the mold 7. Not only can the core disc 4 itself be reinforced by the reinforcing ribs 4w, but also the molten metal constituting the outer frame body 3 casts the reinforcing ribs 4w.
The degree of mechanical engagement between the mandrel 4 and the outer frame body 3 can also be improved.

In the above embodiment, the mold outer frame 1,
9, one core plate 4 is buried, but the present invention is not limited to this, and a plurality of core disks 4 such as two
It can also be buried inside.

In addition, the present invention is not limited to only the above-described embodiment, but can be appropriately changed as needed without departing from the gist.

(Supplementary Note) The following technical idea can be understood from the above description. The mold outer frame according to each claim, wherein a central region of the core disk is exposed to a storage chamber for holding and holding a die, and a periphery of the core disk is cast-in to an outer frame body. The mold outer frame according to each claim, wherein the mold holding surface is machined (cut) and flattened. Since the mold holding surface is flattened, the close contact holding property of the nested mold is improved. Claims according to the manufacturing method, wherein the heating step, the entire mold holding the core plate is housed in a heating chamber of a heating furnace, the method for manufacturing a mold outer frame, wherein both the core plate and the mold are heated . In the claim pertaining to the manufacturing method, a heat treatment step is performed between the casting step and the finishing step, and the heat treatment step is performed in a state in which a part of the core disc cast in the solidified body is exposed to the storage chamber.
Cooling media (eg, air, wind, mist,
Water, oil, etc.) to accelerate the cooling of the core plate, thereby increasing the cooling speed of the core plate. Even when the core plate is cast in the solidified body, the cooling of the core plate can be promoted, which is advantageous for securing the required hardness of the core plate. A mold forming step of forming a fire-resistant mold holding a core plate in a casting cavity, a heating step of heating the mold together with the core plate, A casting medium in which a solidified body is formed by casting the solidified body, and a cooling medium (for example, air) , Wind, mist, water, oil, etc.) to promote cooling of the core plate,
Finishing the solidified body that has undergone the heat treatment step to form an outer frame body, and sequentially performing a finishing step of forming a mold outer frame having the core disk that is harder than the outer frame body. Method of manufacturing the frame.

Even when the core plate is cast in the solidified body, the cooling of the core plate can be promoted, which is advantageous for securing the required hardness of the core plate.

[0070]

According to the mold outer frame of the present invention, even when an excessive pressure load is applied to the mold held by the mold outer frame when the mold outer frame is used, the mold outer frame is not affected. The pressure load is received by the hard core. For this reason, even if the mold outer frame is used for a long time, occurrence of settling on the mold holding surface that defines the storage chamber that holds the mold is suppressed.

According to the method of the present invention, it is possible to manufacture a mold outer frame having an effect of suppressing the settling described above.

According to the method of the present invention, the mold is put together with the
Since heating is performed to a temperature range of 00 to 600 ° C., excessive rapid cooling when the molten metal comes into contact with the core plate is suppressed. This increases the integrity at the boundary surface between the solidified body that casts and surrounds the mandrel and the mandrel, and improves the holdability of the mandrel.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which a first mold outer frame and a second mold outer frame are clamped.

FIG. 2 is a plan view of a first mold outer frame.

FIG. 3 is a cross-sectional view of a first mold outer frame including an outer frame main body having a storage chamber.

FIG. 4 is a cross-sectional view of a first mold outer frame in a state where a mold holding surface is formed on a core disc.

FIG. 5 is a cross-sectional view of a state in which a mold is held in a housing chamber of an outer frame main body of a first mold outer frame.

FIG. 6 is a cross-sectional view showing a state where a core disc is held in a casting cavity of a mold.

FIG. 7 is a graph showing test results obtained by examining the relationship between the heating temperature of the mold and the bonding strength between the outer frame retainer and the core plate.

FIG. 8 is a cross-sectional view showing a state in which a mold is held in a storage chamber of an outer frame body of a first mold outer frame according to another embodiment.

FIG. 9 is a rear view of a core disc according to another embodiment.

FIG. 10 is a cross-sectional view showing a state in which a first mold outer frame and a second mold outer frame are clamped according to a conventional technique.

[Explanation of symbols]

In the figure, 1 is the first mold outer frame, 3 is the outer frame main body, 35 is the mold holding surface, 4 is the core plate, 6 is the accommodation room, 7 is the mold, 70 is the molding cavity mold surface, and 73 is the metal. A mold back surface, 8 is a mold, 9 is a second mold outer frame, and M is a solidified body.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takuo Handa 2-1 Shiraishi-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Japan F-term (Reference) 4E093 NB00 4E094 BB13

Claims (4)

[Claims] 1. A mold outer frame in which a concave housing chamber in which a mold having a molding cavity mold surface for molding a molded product is inserted and held is opened on the surface, an outer frame main body, and the outer frame main body. A mold holding surface to which a mold back surface facing the molding cavity mold surface of the mold is applied, and a core plate harder than the outer frame body. And mold outer frame. 2. The mold outer frame according to claim 1, wherein a projected area of said core plate is larger than a projected area of said mold. 3. The mold outer frame according to claim 1, wherein said core plate is made of stainless steel. 4. A mold forming step of forming a refractory mold holding a core plate in a casting cavity; a heating step of heating the mold together with the core plate to a temperature range of 200 to 600 ° C .; A casting step of forming a solidified body by casting the molten metal into a casting cavity of a mold and solidifying the core disk, and finishing the solidified body to form an outer frame main body, which is harder than the outer frame main body. And a finishing step of forming a mold outer frame having the core plate.