JPH07148565A - Casting method - Google Patents

Abstract

PURPOSE:To provide a casting method of using half-melted casting material having good formability as a material. CONSTITUTION:At the time of casting, a self-standing type short columnar solid casting material A-D is heated and the half-melted casting material having co-existing solid phase and liquid phase is produced and successively, this material A-D is set in a charging port in a mold 1 by holding and carrying this material A-D. Thereafter, the half-melted casting material is passed through a gate 5 connected to the charging port 6 and pressurize-filled up into a cavity for forming. The solid casting material A-D is constituted of an Al alloy. At the time of plotting the thickness (t) of a dendrite layer on the outer peripheral surface of the solid casting material along the X-axis and a vol. fraction Vf of the solid phase in the half melted casting material along the Y-axis, respectively, in the thickness (t) of the dendrite layer within the range of 0mm<=t<=10 mm, the vol. fraction Vf of the solid phase is set to (-3.125t+60)%<=Vf<=(-4.16t+95)%. By this method, the self-standing and the direct holding and carrying of the half-melted casting material can be carried out and this formability can be made good.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting method, and more particularly to a method of casting using a semi-molten casting material in which a solid phase and a liquid phase coexist.

The reason for using such a semi-molten casting material is that it has a large degree of freedom regarding alloy design and shape.

[0003]

2. Description of the Related Art Conventionally, as this type of casting method, a self-supporting short column solid casting material is induction-heated to prepare a semi-molten casting material in which a solid phase and a liquid phase coexist, and then the semi-molten casting material is gripped. A method is known in which it is installed in the inlet of the mold by transporting it and then the latter half of the molten casting material is pressurized and filled into the molding cavity through a gate connected to the inlet (special feature). (See Japanese Patent Publication No. 2-7748).

In this case, from the viewpoint of improving productivity, since the semi-molten casting material is maintained in a self-supporting state and the casting material is directly gripped and transferred, the volume of the solid phase in the semi-molten casting material is increased. The fraction Vf is set as high as 75 to 90%, and a dendrite layer exists on the outer peripheral surface of the solid casting material.

[0005]

However, when the volume fraction Vf of the solid phase is high and the dendrite layer is present as described above, when the semi-molten casting material is pressure-filled into the cavity, the liquid Since the phases preferentially pass through the gate, the volume fraction Vf of the solid phase of the semi-molten casting material remaining in the charging port becomes higher than the initial value due to the inclusion of debris of the dendrite layer. . As a result, in the vicinity of the gate entrance of the charging port, clogging of the semi-molten casting material occurs and chipping occurs in the casting, and the filling pressure of the semi-molten casting material in the cavity due to the preferential passage of the liquid phase through the gate Since it fluctuates, there is a problem that segregation is likely to occur in the casting.

In view of the above, the present invention specifies the material of the solid casting material and the relationship between the thickness t of the dendrite layer in the solid casting material and the solid phase volume fraction Vf of the semi-molten casting material. It is an object of the present invention to provide the above-mentioned casting method that enables the semi-molten casting material to be self-supporting and can be transferred by direct gripping, and has good moldability.

Further, according to the present invention, the volume fraction Vf of the solid phase in the semi-molten casting material can be significantly reduced as compared with the conventional method, the moldability thereof is improved, and the collapse of the semi-molten casting material is prevented. It is an object of the present invention to provide the above-mentioned casting method which avoids the above-mentioned problems and enables the transfer by gripping.

[0008]

In the casting method according to the first aspect of the present invention, a self-supporting short column solid casting material is heated to prepare a semi-molten casting material in which a solid phase and a liquid phase coexist, and then the semi-solid casting material is prepared. When the molten casting material is placed in the inlet of the mold by gripping and transferring it, the semi-molten casting material is then pressure-filled into the molding cavity by passing through the gate connected to the inlet, The solid casting material is composed of an Al alloy, and the thickness t of the dendrite layer on the outer peripheral surface of the solid casting material is on the X axis, and the volume fraction Vf of the solid phase in the semi-molten casting material is on the Y axis. When the thickness t of the dendrite layer is 0 mm ≦ t ≦ 10 mm, the volume fraction Vf of the solid phase is (−3.125t + 60)% ≦ Vf.
It is characterized by setting ≦ (−4.16t + 95)%.

Further, the casting method according to the second aspect of the present invention includes the steps of accommodating the short columnar solid casting material in a cylindrical holder and allowing the solid casting material and the cylindrical holder to stand on their own, and the solid casting in the cylindrical holder. Heating the material, preparing a semi-molten casting material in which a solid phase and a liquid phase coexist, and a step of gripping the tubular holder and transferring the semi-molten casting material to the vicinity of the inlet of the mold, A step of separating the semi-molten casting material from the inside of the cylindrical holder and setting it in the charging port; and pressure-filling the semi-molten casting material into the molding cavity through a gate connected to the charging port. And a process are used.

[0010]

In the first aspect of the invention, when the thickness t of the dendrite layer is relatively thick, the volume fraction Vf of the solid phase is set low, while the thickness t of the dendrite layer is relatively thin or the dendrite thereof is relatively thin. When there is no layer, the solid volume fraction Vf is set high.

Therefore, in the former case, the shape-retaining ability of the dendrite layer, and in the latter case, the semi-molten casting material can be transferred by self-standing and by direct grasping due to the shape-retaining ability with the increase of the amount of solid phase. On the other hand, the moldability is good in the former case because the solid phase volume fraction Vf is low, and in the latter case because the dendrite layer is thin or absent.

The thickness t = 0 of the dendrite layer corresponds to the case where the solid casting material is cut to remove the dendrite layer. When the thickness t is t> 10 mm, an excessive pressure is required to crush the dendrite layer, which is not preferable in terms of equipment cost.

Further, the volume fraction Vf of the solid phase is Vf <(-
At 3.125t + 60)%, the amount of the liquid phase dissolved in the semi-molten casting material increases, so that the self-sustainability cannot be maintained. On the other hand, at Vf> (-4.16t + 95)%, the formability deteriorates, and Clogging of the semi-molten casting material occurs in the inlet.

In the second invention, when the solid casting material is heated in the cylindrical holder, even if the volume fraction Vf of the solid phase in the semi-molten casting material is lowered, the leakage of the liquid phase to the outside can be prevented. It is also possible to prevent the semi-molten cast material from collapsing. This improves yield and prevents damage to the heating device due to leakage of the liquid phase.

Further, even a semi-molten cast material having a low solid phase volume fraction Vf can be stably and reliably transferred by gripping the cylindrical holder.

Further, during heating and transfer, the heat-retaining effect of the cylindrical holder can be obtained, so that the heating time for preparing the semi-molten casting material can be shortened and the soaking degree of the semi-molten casting material can be improved.

Moreover, since the molding can be performed at a high temperature, the semi-molten casting material can be continuously passed through the gate, and the filling pressure of the semi-molten casting material in the cavity can be stabilized. It is possible to improve the formability of the semi-molten casting material and obtain a high-quality casting without chipping or segregation. The molding under the high temperature brings an effect of expanding the material selection range of the casting material.

[0018]

【Example】

[Example I] FIG. 1 schematically shows a pressure casting apparatus. The mold 1 of the pressure casting apparatus is composed of a horizontal fixed mold 2 and a movable mold 3 that moves in a vertical direction facing the fixed mold 2. The molds 2 and 3 form a molding cavity 4 having a circular cross section and A gate 5 communicating with one end is formed, and the gate 5 communicates with a charging port 6 for semi-molten casting material of the fixed mold 2. The fixed mold 2 is provided with a sleeve 7 communicating with the loading port 6,
A pressure plunger 8 that is inserted into and removed from the charging port 6 is slidably fitted into the sleeve 7.

Table 1 shows the composition of the Al alloy that constitutes the solid casting material.

[0020]

[Table 1]

The solid casting material is a molten alloy having an Al alloy composition and is cut out from a long material produced under the application of the electromagnetic stirring continuous casting method to form a short columnar shape.

Table 2 shows the thickness t, the diameter and the length of the dendrite layer on the outer peripheral surface of various solid casting materials A to D. The change in thickness of the dendrite layer is made by changing the casting conditions, and the portion inside the dendrite layer is equiaxed. Therefore, the solid phase in the semi-molten cast material is spherical.

[0023]

[Table 2]

The solid casting material D in which the thickness t of the dendrite layer is t = 0 is obtained by removing the dendrite layer by cutting the outer peripheral surface of the solid casting material C.

As shown in FIG. 2, in order to perform a heating test, the solid casting material A is erected on a vertically movable support base 9 of the induction heating device, and the support base 9 is raised to raise the solid casting material A. It was installed in the heating coil 10. Then, the solid casting material A is heated under the conditions of a frequency of 1 kHz and an output of 37 kW to prepare a semi-molten casting material A (the same reference numeral as that of the solid casting material, which will be the same hereinafter) is prepared. The volume fraction Vf of the solid phase was variously changed by changing the temperature in the range of 600 ° C. The heating time was 7 minutes (constant), and the temperature distribution of the semi-molten casting material A was kept within the range of ± 3 ° C.

Then, at each heating temperature, it was observed whether or not the semi-molten casting material A could maintain the self-standing state, and the volume fraction Vf of the solid phase was determined. The same heating test was also performed on the solid casting materials B to D.

Next, in order to perform a molding test, the same solid casting materials A to D as described above are used, and the same heat treatment as described above is carried out. Then, as shown in FIG. The casting materials A to D are taken out of the heating coil 10 and the one that maintains the self-supporting state is charged into the charging port 6 of the mold 1 through the gripping tool 11 as shown in FIG. 8 moving speed 0.07 m / sec, mold temperature 250
Gate-passing speed of semi-molten casting materials A to D, 2m / se
Under the condition of c, the semi-molten casting materials A to D were pressurized and passed through the gate 5 to successively fill the cavity 4 with a high-speed laminar flow. Then, by holding the pressure plunger 8 at the end of the stroke, a pressure is applied to the semi-molten casting materials A to D filled in the cavity 4, and the semi-molten casting materials A to D are solidified under the pressure. I got a casting.

Table 3 shows the heating test and molding test results. In Table 3, the column of "self-supporting" corresponds to the heating test result, and the mark "◎" indicates that the semi-molten casting material has no melt-out of the liquid phase, and the semi-melting casting material surely maintains the self-supporting state. Means that Further, the mark "○" means that the semi-molten casting material is melted out, but the semi-molten casting material can stand on its own. Further, the mark "X" means that the semi-molten casting material has a large amount of liquid phase melted out, and the semi-molten casting material cannot stand on its own.

The column "moldability" corresponds to the result of the molding test, and the mark "○" means that a cast product without casting defects can be obtained. The symbol "x" means that the semi-molten material is clogged in the vicinity of the gate 5 inlet of the charging port 6. Further, the "-" mark means that the semi-molten cast material could not be transferred by the gripping tool 11 because the amount of the liquid phase melted out was large, and therefore the molding operation could not be performed.

[0030]

[Table 3]

In Table 3, the range of this example is that the column of "independence" is marked with "⊚" or "○" and the column of "moldability" is marked with "○".

The same heating test and molding test as described above were conducted using another solid casting material, and when the thickness t of the dendrite layer was 0 mm ≦ t ≦ 10 mm, the self-sustaining property of the semi-molten casting material was “◎”. When the volume fraction Vf of the solid phase in which the mark or the mark “◯” is obtained and the moldability is in the mark “◯” is obtained, the results shown in FIG. 4 are obtained.

That is, in FIG. 4, when the thickness t of the dendrite layer on the outer peripheral surface of the solid casting material is plotted on the X axis and the volume fraction Vf of the solid phase in the semi-molten casting material is plotted on the Y axis, the dendrite layer is obtained. When the thickness t of the solid is 0 mm ≦ t ≦ 10 mm, the volume fraction Vf of the solid phase is (−3.125t + 60)
% ≦ Vf ≦ (−4.16t + 95)% is set. The volume fraction Vf of the solid phase is Vf ≧ (−2.9t + 75)
%, There was no dissolution of the liquid phase, while Vf <(-
At 2.9t + 75)%, dissolution of the liquid phase occurs. FIG. 4 shows each example of Table 3 by coordinates.

As is apparent from FIG. 4, when the thickness t of the dendrite layer is relatively thick, the volume fraction Vf of the solid phase is set low, while the thickness t of the dendrite layer is relatively thin, Alternatively, when the dendrite layer is not present, the solid phase volume fraction Vf is set high.

Therefore, in the former case, the shape-retaining ability of the dendrite layer, and in the latter case, the shape-retaining ability with an increase in the amount of the solid phase enables the semi-molten cast material to be transferred by self-standing and direct grasping. On the other hand, the moldability is good in the former case because the solid phase volume fraction Vf is low, and in the latter case because the dendrite layer is thin or absent.

[Example II] FIG. 5 schematically shows a pressure casting apparatus. The mold 1 of the pressure casting device is a vertical fixed mold 2
And a movable mold 3 that moves in the left-right direction facing it, and a mold 5 having a circular cross section and a gate 5 communicating with the lower end thereof are formed by the molds 2 and 3, and the gate 5 is a fixed mold. It communicates with the horizontal semi-molten casting material inlet 6 of the mold 2. The fixed mold 2 is provided with a sleeve 7 that communicates with the loading port 6, and a pressure plunger 8 that is inserted into and removed from the loading port 6 is slidably fitted into the sleeve 7. Further, a rod insertion hole 12 that faces the loading port 6 is formed in the movable mold 3, and an extrusion rod 13 is slidably fitted in the rod insertion hole 12.

Solid casting materials A to D (see Table 2) similar to those in Example I, inner diameter 81 mm, outer diameter 86 mm, length 105
A cylindrical holder 14 for semi-molten casting material having a size of mm and having open both end surfaces was prepared. The cylindrical holder 14 is made of boron nitride (BN) to prevent the semi-molten casting material from adhering.

As shown in FIG. 6, in order to perform a heating test, the solid casting material A is housed in a cylindrical holder 14 and these A and 14 are moved up and down in an induction heating apparatus.
The solid casting material A is erected so that an equal gap is formed around the solid casting material A, and the supporting table 9 is raised to raise the solid casting material A.
And the cylindrical holder 14 was installed in the heating coil 10.
The support base 9 is made of alumina, which has a good heat retaining property. Then, the solid casting material A is heated under the conditions of a frequency of 1 kHz and an output of 37 kW to prepare a semi-molten casting material A. At that time, the heating temperature is changed in the range of 568 to 600 ° C., and the volume fraction of the solid phase is changed. Vf was variously changed. The heating time was 7 minutes (constant), and the temperature distribution of the semi-molten casting material A was kept within the range of ± 3 ° C.

Then, for each heating temperature, the volume fraction Vf of the solid phase in the semi-molten casting material A was determined, and after air cooling to room temperature, the contact state between the solid casting material A and the cylindrical holder 14 was visually observed. In the solid casting material A, as shown in FIG.
There were those that were in contact with and those that were not. The same heating test was also performed on the solid casting materials B to D.

Next, in order to perform a molding test, the same solid casting materials A to D as described above are used, and the same heat treatment as described above is performed. Then, as shown in FIG. The cylindrical holder 1 in which the casting materials A to D and the cylindrical holder 14 are taken out of the heating coil 10 to maintain the self-standing state.
4 is grasped by the grasping tool 11 and rotated by 90 ° and transferred, and as shown in FIG. 9, the cylindrical holder 14 and a part of the semi-molten casting materials A to D are partially charged into the mold 1 at the inlet 6 edge portion. Charged into. In this case, even the semi-molten casting material having a low solid phase volume fraction Vf can be gripped by the cylindrical holder 14 and stably and reliably transferred.

As shown in FIG. 10, the extruding rod 13 is moved forward to extrude the semi-molten casting materials A to D into the charging port 6 and separate them from the cylindrical holder 14, and then the cylindrical holder 14 is used.
Was moved from between the molds 2 and 3 to close the molds 2 and 3.

Then, as shown in FIG. 11, the moving speed of the pressure plunger 8 is 0.5 m / sec and the mold temperature is 200.
The semi-molten casting materials A to D were passed through the gate 5 while being pressurized, and the cavities 4 were successively filled with a high-speed laminar flow at a temperature of 2 ° C. at a gate passage speed of the semi-molten casting materials of 2 m / sec. Then, the semi-molten casting material A filled in the cavity 4 by holding the pressure plunger 8 at the end of the stroke.
To D are applied with pressure, and under the pressure, the semi-molten casting material A
~ D was solidified to obtain a casting.

In this case, since it is possible to perform the molding at a high temperature in which the volume fraction Vf of the solid phase in the semi-molten casting materials A to D is reduced, the semi-molten casting materials A to D are continuously gated.
And it is possible to stabilize the filling pressure of the semi-molten casting materials A to D in the cavity 4, etc.
It is possible to improve the formability of the semi-molten casting materials A to D and obtain a high-quality casting without chipping or segregation.

Table 4 shows the heating test and molding test results.

In Table 4, the column of "independence" corresponds to the result of the heating test, and the mark "○" indicates that the semi-molten casting material does not melt or deform and the semi-molten casting material is a cylindrical holder. It means the case where it is not in contact with 14. Further, the mark "x" means that the liquid phase is melted out or deformed in the semi-molten casting material, and the semi-molten casting material is in contact with the cylindrical holder 14 as shown in FIG.

The column of "formability" corresponds to the result of the forming test, and the mark "○" means that a cast product without casting defects can be obtained. The symbol "x" means that the semi-molten material is clogged in the vicinity of the gate 5 inlet of the charging port 6. Further, the "-" mark indicates that the amount of the liquid phase melted out in the semi-molten casting material cannot be transferred by the gripping tool 11, or even if the transfer can be performed, the extrusion rod 13 is in the semi-molten casting material. It means that it could not be detached from the cylindrical holder 14 because it was pierced by and the molding operation could not be performed.

[0047]

[Table 4]

In Table 4, the range of this embodiment is that the column of "independence" is marked with "x" and the column of "moldability" is marked with "○". In addition, comparing Tables 3 and 4,
For example, in the semi-molten casting material A, although the heating temperature and the volume fraction Vf of the solid phase are the same, the data regarding "independence" are different.
This is due to the difference between the case where the cylinder holder is not used and the case where the cylindrical holder 14 is used to receive the heat retaining effect.

The same heating test and molding test as described above were conducted using another solid casting material, and when the thickness t of the dendrite layer was 0 mm ≦ t ≦ 10 mm, the self-supporting property of the semi-molten casting material was the above-mentioned “x”. When the volume fraction Vf of the solid phase in which the solid state is marked and the moldability is marked with “◯” is obtained, the results shown in FIG. 12 are obtained.

That is, in FIG. 12, when the thickness t of the dendrite layer on the outer peripheral surface of the solid casting material is taken as the X axis and the volume fraction Vf of the solid phase in the semi-molten casting material is taken as the Y axis, the dendrite layer is obtained. When the thickness t of the solid phase is 0 mm ≦ t ≦ 10 mm, the volume fraction Vf of the solid phase is 25% ≦ Vf ≦ (-4.
16t + 95)%. FIG. 12 shows each example of Table 4 by coordinates.

In FIG. 12, the thickness t of the dendrite layer is
Is 0 mm ≦ t ≦ 10 mm, the solid phase volume fraction Vf is (−
2.9t + 75)% <Vf ≦ (-4.16t + 95)%
Although the semi-molten casting material existing in the range of (1) has melted out or deformed the liquid phase, it can be self-supported without using the cylindrical holder 14, but it may collapse, so
The yield is improved when the tubular holder 14 is used.

Further, the volume fraction Vf of the solid phase is 25% ≦ Vf
The semi-molten casting material in the range of ≦ (−2.9t + 75)% will fall unless the cylindrical holder 14 is used.

As is clear from a comparison between FIG. 4 and FIG. 12, when the cylindrical holder 14 is used, the volume fraction Vf of the solid phase is lower than when it is not used, that is, Vf <(-
At 3.125t + 60)%, the formable area can be expanded.

Even if the solid phase volume fraction Vf of the semi-molten casting material is lowered, the cylindrical holder 14 can prevent the liquid phase from leaking to the outside and prevent the semi-molten casting material from collapsing. be able to. This prevents damage to the heating device due to leakage of the liquid phase and improves yield.

Next, using the solid casting material C, a semi-molten casting material C having a solid phase volume fraction Vf of Vf = 50% is prepared for the case where the cylindrical holder 14 is used and the case where it is not used. When the heating time and heat input required for this purpose were investigated, the results shown in Table 5 were obtained. The temperature of the solid casting material C before heating was 20 ° C.

[0056]

[Table 5]

As is clear from Table 5, the cylindrical holder 14
When using, the heat-retaining effect of the cylindrical holder 14 can be obtained, so that the heating time for preparing the semi-molten casting material can be shortened and the heat input amount can be reduced as compared with the case where the cylindrical holder 14 is not used. In addition, the soaking degree of the semi-molten casting material can be improved.

[0058]

According to the first aspect of the present invention, the solid casting material made of Al alloy is used, and the thickness t of the dendrite layer in the solid casting material and the volume fraction of the solid phase in the semi-molten casting material. By specifying the relationship with Vf as described above, castings with good casting quality can be mass-produced with high yield.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, there is an effect that the moldable region can be expanded in a range where the volume fraction Vf of the solid phase is low.

[Brief description of drawings]

FIG. 1 is a vertical side view showing an example of a pressure casting device.

FIG. 2 is a vertical sectional side view of an essential part showing an example of a heating method for a solid casting material.

FIG. 3 is a vertical cross-sectional side view of an essential part showing an example when the transfer of the semi-molten casting material is started.

FIG. 4 is a graph showing the relationship between the thickness of the dendrite layer and the volume fraction of the solid phase in one example.

FIG. 5 is a vertical sectional side view showing another example of the pressure casting apparatus.

FIG. 6 is a vertical sectional side view of a main part showing another example of a heating method for a solid casting material.

FIG. 7 is a vertical cross-sectional side view of essential parts showing the relationship between the solid casting material after heating and cooling and the cylindrical holder.

FIG. 8 is a vertical cross-sectional side view of an essential part showing another example at the time of starting the transfer of the semi-molten casting material.

FIG. 9 is a vertical sectional side view showing the end of transfer of the semi-molten casting material.

FIG. 10 is a vertical cross-sectional side view showing a state in which a semi-molten casting material is installed at a charging port of a mold.

FIG. 11 is a vertical cross-sectional side view showing a state in which a cavity is filled with a semi-molten casting material.

FIG. 12 is a graph showing the relationship between the thickness of the dendrite layer and the solid phase volume fraction in another example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold 4 Cavity 5 Gate 6 Loading port 8 Pressurizing plunger 11 Grip tool 13 Extrusion rod 14 Cylindrical holder A to D Solid casting material, semi-molten casting material

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C22C 1/02 503 J 21/02

Claims (4)

[Claims] 1. A self-supporting short column solid casting material (A to D)
Are heated to prepare semi-molten casting materials (A to D) in which a solid phase and a liquid phase coexist, and then the semi-molten casting materials (A to D) are prepared.
It is installed in the charging port (6) of the mold (1) by gripping and transferring D), and then the semi-molten casting material (A to
When D) is passed through the gate (5) connected to the charging port (6) and pressure-filled in the molding cavity (4), the solid casting materials (A to D) are made of Al alloy. , The thickness t of the dendrite layer on the outer peripheral surface of the solid casting material (A to D) on the X axis, and the semi-molten casting material (A to D).
When the volume fraction Vf of the solid phase in D) is taken along the Y axis, the thickness t of the dendrite layer is 0 mm ≦ t ≦ 10.
In mm, the volume fraction Vf of the solid phase is (-3.125
A casting method characterized by setting t + 60)% ≦ Vf ≦ (−4.16t + 95)%. 2. A short columnar solid casting material (A to D) is housed in a cylindrical holder (14) to obtain the solid casting material (A to D).
D) and the step of free-standing the cylindrical holder (14), and the solid casting material (A to D) in the cylindrical holder (14).
A semi-molten casting material (A to D) in which a solid phase and a liquid phase coexist, and the cylindrical holder (14)
Grasping the semi-molten casting material (A to D) to mold (1)
Of the semi-molten casting materials (A to D) from the inside of the cylindrical holder (14) and installing the semi-molten casting materials (A to D) inside the loading port (6); A step of casting the molten casting materials (A to D) into the molding cavity (4) through a gate (5) connected to the charging port (6) under pressure. 3. The solid casting material (A to D) is composed of an Al alloy, the thickness t of the dendrite layer on the outer peripheral surface of the solid casting material (A to D) is on the X axis, and the semi-molten casting material is When the volume fraction Vf of the solid phase in (A to D) is taken on the Y axis, the thickness t of the dendrite layer is 0 mm ≦.
When t ≦ 10 mm, the volume fraction Vf of the solid phase is 25%
The casting method according to claim 2, wherein ≦ Vf ≦ (−4.16t + 95)% is set. 4. The solid casting material (A to D) is composed of an Al alloy, the thickness t of the dendrite layer on the outer peripheral surface of the solid casting material (A to D) is on the X axis, and the semi-molten casting material is When the volume fraction Vf of the solid phase in (A to D) is taken on the Y axis, the thickness t of the dendrite layer is 0 mm ≦.
When t ≦ 10 mm, the volume fraction Vf of the solid phase is 25%
3. Setting to ≦ Vf ≦ (−2.9t + 75)%.
The casting method described.