JP2000054047A - Hypoeutectic Al-Si alloy member in which primary Si is crystallized and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Al-Si alloy material in which primary crystal Si is crystallized out in a hypo-eutectic compsn. and combining wear resistance and toughness. SOLUTION: This hypo-eutectic Al-Si alloy member is the one contg. 6.5 to 11.0% Si and 0.001 to 0.01% P, and in which, in the secondary cast structure obtd. by reheating a casting material to a solid-liq. coexistent region and executing casting, primary crystal Si having 6 to 9 μm average grain size is dispersed by 1 to 3% area ratio. The member is produced by reheating a primary casting material at 560 to 580 deg.C in a vessel to form into a half-melted state, thereafter press-fitting it into a mold for diecasting or molten metal forging and molding into a secondary casting material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hypoeutectic Al-Si alloy member having improved abrasion resistance by crystallization of primary crystal Si and excellent impact resistance (toughness), and a method for producing the same.

[0002]

2. Description of the Related Art Hyper-eutectic Al- such as A390, ADC14, etc.
The Si-based alloy exhibits excellent wear resistance because primary Si is crystallized and dispersed in the matrix. Primary crystal Si is effective for improving wear resistance, but tends to be coarsened by a normal production method. The tendency of primary Si to become coarser becomes more pronounced as the Si content increases. Si itself is a brittle material, and when coarse primary Si is dispersed in the matrix, cracks, breakage, and the like are likely to occur starting from the primary Si when an external force is applied. As a result, impact resistance (toughness) decreases. On the other hand, in the hypoeutectic composition, α-Al is crystallized from the molten metal as primary crystals, and Si is crystallized as eutectic Si. Eutectic Si is finely crystallized and is uniformly dispersed at crystal grain boundaries and boundaries of dendrite cells. Therefore, AC4A, A
A hypoeutectic Al-Si alloy such as C4C exhibits excellent impact resistance (toughness).

[0003]

However, in the hypoeutectic composition, since the crystallization of primary Si which is effective for improving the wear resistance cannot be essentially expected, it is compared with the hypereutectic Al-Si alloy. And a material with poor abrasion resistance. This hypoeutectic Al-
When it becomes possible to crystallize primary Si having an appropriate grain size in a Si-based alloy, a material having abrasion resistance in addition to excellent impact resistance (toughness) unique to a hypoeutectic system is obtained. .

[0004]

DISCLOSURE OF THE INVENTION The present invention has been devised in order to meet such a demand, and a portion where eutectic Si is crystallized in a primary casting material becomes locally rich in Si. By making use of the fact that the Si-rich portion is selectively dissolved to form a secondary casting structure in which primary Si is crystallized,
An object is to obtain a hypoeutectic Al-Si alloy member excellent in both wear resistance and impact resistance. Hypoeutectic Al- of the present invention
In order to achieve the object, the Si alloy member is made of Si: 6.
5 to 11.0% by weight, P: 0.001 to 0.01% by weight, with the balance being substantially hypoeutectic Al-Si having a composition of Al
An alloy having an average grain size of 6 to 9 μm in a secondary casting structure obtained by reheating a casting material to a solid-liquid coexistence region and casting.
m primary crystal Si is characterized by being dispersed at an area ratio of 1 to 3%.

[0005] The hypoeutectic Al-Si alloy used in the present invention further comprises Sr: 0.003-0.04% by weight, Sb:
0.05 to 0.25% by weight, Na: 0.001 to 0.0
1% by weight, one or more of Ca: 0.001 to 0.02% by weight, Ti: 0.01 to 0.2% by weight, B: 0.
One or more of 0001 to 0.04% by weight, and / or
Alternatively, one or more of Cu: 0.2 to 2% by weight, Mg: 0.2 to 0.7% by weight, and Mn: 0.1 to 0.6% by weight can be contained. This hypoeutectic Al-Si alloy member is obtained by reheating a primary casting material obtained by casting a hypoeutectic Al-Si alloy having the above composition to a temperature of 560 to 580 ° C in a container, to a semi-molten state. It is manufactured by press-fitting into a die casting or molten metal forging die and forming it into a secondary casting material. When die-casting or melt-forging a semi-eutectic hypoeutectic Al-Si alloy, it is preferable to set the cooling rate to 2 ° C / sec or more and the pressure to 500 kg / cm ² or more. The secondary casting material becomes a forged part by warm forging or hot forging.

[0006]

The hypoeutectic Al-Si alloy member of the present invention is manufactured through the steps of primary casting, remelting and secondary casting, and is subjected to warm forging or hot forging as required. Eutectic Si crystallized in the cast structure obtained in the primary casting is adjusted to an average particle size that is easily redissolved by regulating the contents of Si, P and the like. In the cast structure obtained by the primary casting, eutectic Si is crystallized between the α-Al crystal dendrites as shown in FIG. The crystallized portion of eutectic Si is locally rich in Si. When the primary cast material is heated to a temperature range of 560 to 580 ° C., a eutectic Si crystallization portion having a low melting point is selectively dissolved, and a semi-molten state is left in which α-Al crystals remain undissolved. When a semi-molten Al-Si alloy is secondarily cast, S
Primary crystal Si from the melt where the i content is locally high
Crystallizes out. As a result, as shown in FIG. 2, primary Si was crystallized in this way despite the hypoeutectic composition,
A hypoeutectic Al-Si alloy member with improved wear resistance in addition to excellent impact resistance having a hypoeutectic composition can be obtained.

Hereinafter, the components, contents, production conditions, and the like of the hypoeutectic Al-Si alloy used for the secondary cast part or the forged part of the present invention will be described. Si: 6.5 to 11.0% by weight The range of the Si content of 6.5 to 11.0% by weight in the Al-Si system belongs to the hypoeutectic composition. Therefore, when using a normal casting method, Si is not crystallized as primary Si,
It becomes fine eutectic Si and crystallizes and disperses at crystal grain boundaries and boundaries of dendrite cells. The obtained cast material has good impact resistance, but is inferior in wear resistance. However, when the secondary casting is performed by remelting the primary casting material according to the present invention, even if the Si content is below the eutectic point, the Si content is increased to 6.5 to 6.5.
When the content is maintained in the range of 11% by weight, primary crystal Si larger than eutectic Si is crystallized from a molten portion, and wear resistance is improved.
The Si content of 6.5 to 11% by weight is also effective in improving the flow of molten metal during casting. However, if the Si content is less than 6.5% by weight, the amount of primary crystal Si to be crystallized is too small and does not contribute to the improvement of wear resistance. Conversely, if the Si content exceeds 11% by weight, coarse primary crystal Si is crystallized in the primary casting material and wear resistance is improved, but primary crystal Si becomes a starting point of impact cracks and impact resistance is deteriorated.

P: 0.001 to 0.01% by weight When the primary casting material is heated to a predetermined temperature to be in a semi-molten state, eutectic Si moves to the melt portion. P contained in the melt portion acts as a crystal nucleus for crystallizing primary Si in the melt portion when the semi-eutectic hypoeutectic Al-Si alloy is secondarily cast and cooled. When the P content is maintained in the range of 0.001 to 0.01% by weight, an appropriate amount of crystal nuclei effective for precipitation of primary Si is generated. If the P content is less than 0.001% by weight, the number of crystal nuclei is too small, and the crystallization of primary Si becomes insufficient. Conversely, if the P content exceeds 0.01% by weight, the flow of the molten metal deteriorates. Primary Si having an average particle size of 6 to 9 μm is dispersed at an area ratio of 1 to 3%.
When primary casting of a hypoeutectic Al-Si alloy with regulated secondary casting structure Si and P content is semi-molten and subjected to secondary casting, primary crystal S
Although i is crystallized, the particle size and area ratio of the primary crystal Si affect wear resistance and impact resistance. In order to obtain good wear resistance, it is necessary to control the average grain size of the primary crystal Si in the range of 6 to 9 μm and the area ratio in the range of 1 to 3%. With primary crystal Si having an average particle size of less than 6 μm, the wear resistance is insufficient, and conversely, with an average particle size of more than 9 μm, the impact resistance tends to deteriorate. Similarly, if the area ratio of the primary crystal Si is less than 1%, the wear resistance is insufficient, and if it exceeds 3%, the impact resistance is deteriorated.

Sr: 0.003-0.04% by weight, S
b: 0.05 to 0.25% by weight, Na: 0.001 to
0.01% by weight, Ca: 0.001 to 0.02% by weight :
These alloy components are prepared by melting a hypoeutectic Al-Si alloy in which the contents of Si and P are regulated in accordance with the present invention, and performing die casting.
When it is made into a primary casting material by C casting or the like, it has an effect of miniaturizing eutectic Si. The refined eutectic Si is easily dissolved at the time of re-dissolution in a later step. Further, even in the subsequent secondary casting stage such as die casting or molten forging, the eutectic Si other than the target primary crystal Si is refined, and the effect of improving impact resistance is exhibited. If any of the alloy components is less than the specified range, the effect of addition is reduced. On the other hand, if the added amount exceeds the specified range, the flow of the molten metal is deteriorated, and nonmetallic inclusions such as oxides derived from the added components are increased. The increased non-metallic inclusions are consequently caught in the product and cause the impact resistance to deteriorate.

[0010] Ti: 0.01-0.2% by weight, B: 0.
0001-0.04% by weight When a hypoeutectic Al-Si alloy having a regulated Si and P content is cast into a primary cast material, α- crystallized as a primary crystal.
It has the function of refining Al crystals. The primary α-Al crystal is not melted during die casting or molten forging in the subsequent process, so that the smaller the particle size, the better the fluidity of the molten metal, and the better the formability and pushability. Such an effect can be obtained when Ti: 0.01
-0.2% by weight and / or B: 0.0001-0.04
It becomes remarkable in the range of weight%. Less than 0.01% by weight of Ti
If the content of B is less than 0.001% by weight, the α-Al crystal grows large, and the effect of improving the formability and the hot-rolling property is reduced. Conversely, a Ti content exceeding 0.2% by weight or 0.0%
When the B content exceeds 4% by weight, a large intermetallic compound is formed, and the impact resistance is deteriorated. The α-Al crystal grows in a dendrite shape, but its growth is suppressed by adding an appropriate amount of Ti or B or controlling casting conditions. The dendrite arm spacing is preferably as small as possible from the standpoint of ensuring good moldability, hot-rolling property, etc., and the average particle diameter is preferably regulated to 50 μm or less.

[0011] Cu: 0.2 to 2% by weight is an alloy component added as necessary, and has an effect of improving the strength and wear resistance of the matrix. However, when a large amount of Cu exceeding 2% by weight is added, an Al-Cu-based molten metal having a low melting point and easy to segregate is generated, and Al-Cu is added.
An intermetallic compound such as -Mg or Cu-Mg is crystallized as a segregation layer. The segregation layer causes a significant decrease in impact resistance. Conversely, if the Cu content is less than 0.2% by weight, the strength and wear resistance are not significantly improved by the addition of Cu. In addition, the addition of an appropriate amount of Cu is performed by T6 treatment.
precipitating u _2, etc., to improve the strength of the T6 treatment material. Mg: 0.2 to 0.7% by weight An alloy component added as needed, precipitates as Mg ₂ Si by T6 treatment, and improves the strength of the T6 treated material. If the Mg content is less than 0.2% by weight, the amount of Mg ₂ Si precipitated by the T6 treatment is small, and the effect on the strength improvement is small. Conversely, if the Mg content exceeds 0.7% by weight, the entrainment of Mg-based oxides increases, and the impact resistance deteriorates.

Mn: 0.1 to 0.6% by weight An alloy component added as necessary, and Al-Mn-
It is crystallized as a Si-based intermetallic compound to improve wear resistance. Such an effect becomes remarkable at a Mn content of 0.1% by weight or more. However, when the Mn content exceeds 0.6% by weight, a huge crystallized substance is formed, and the impact resistance is deteriorated. In addition to the alloy components listed above, the hypoeutectic Al-Si alloy targeted by the present invention may contain Fe which has an effect of preventing seizure on a mold during die casting. However, when the Fe content is large, an Al-Si-Fe-based crystallized substance is generated, which lowers the fluidity in a semi-molten state,
It has an adverse effect on moldability and flowability. From this point, Fe
When added as an alloy component, the content is 0.1 to
It is restricted to the range of 0.5% by weight. Ni, Zn, Cr, etc.
Other elements are more preferable because they have a bad influence on impact resistance and corrosion resistance.
It is regulated as follows.

[0013] The hypoeutectic Al-Si alloy designed as above is as follows :
After the melting, a molten metal treatment such as degassing, miniaturization, and deslagging is performed according to a conventional method. Next, die casting (ingot casting),
A primary casting material is manufactured by DC casting or the like. It is preferable that the primary cast material has a fine eutectic Si and a fine dendrite arm spacing of an α-Al crystal. As a casting method for reducing the dendrite arm spacing of α-Al crystals, a method of adding a Ti—B-based crystal refining agent,
A method in which the solidification interface is magnetically or mechanically stirred to separate α-Al crystal dendrite arm spacing to make the solidification finer or the like is employed. The α-Al crystal dendrite remains in the molten metal without melting when the primary cast material is brought into a semi-molten state by reheating prior to secondary casting. Therefore, α
-The finer the dendrite arm spacing of Al crystals, the better the fluidity in the semi-molten state. As a result, the feeder effect is effective, and casting defects such as porosity and shrinkage cavities are less likely to occur when forming into a secondary casting material, and a secondary casting material having a sound casting structure can be obtained. Further, the finer the eutectic Si crystallized in the primary casting material, the more easily the primary casting material becomes a semi-molten state by reheating.

[0014] The primary cast material is brought into a semi-molten state by heating at 560-580 ° C. The heating temperature range of 560 to 580 ° C. selectively melts the eutectic phase such as eutectic Si crystallized at the grain boundary of the α-Al crystal and the boundary of the dendrite cell without dissolving the α-Al crystal. This is an effective temperature range for performing
In the phase diagram of the Al-Si system, the melting point of eutectic Si is almost 575.
° C, but Mg ₂
A ternary or higher eutectic of an Al-Si-intermetallic compound derived from Si, Al ₂ Cu, or the like exists. Therefore, eutectic S
Investigation and study of the dissolution state of i revealed that dissolution of eutectic Si began at 560 ° C. However, when the temperature exceeds 580 ° C., melting of the surrounding α-Al crystals starts, the Si content in the melt decreases, the amount of primary crystal Si crystallized during cooling decreases, and the amount of fine eutectic Si increases. Specifically, P
Containing 0.001% by weight and 0.004% by weight of Al
As shown in FIG. 3 in which the relationship between the Si content and the primary Si crystallization temperature was investigated in the Si system, when P: 0.001% by weight, the eutectic was observed until the Si content was approximately 13% by weight. The temperature is 574 ° C., and a small amount of primary crystal Si and a large amount of eutectic Si are crystallized. On the other hand, in a system to which 0.004% by weight of P is added, a large amount of primary crystal Si is crystallized. From this, when primary Si is crystallized at 580 ° C., S
It can be seen that the i content is approximately 13% by weight.

When the relationship between the Si content and the primary crystallization temperature of Si in FIG. 3 is applied to the experimental results of the hypoeutectic Al—Si alloy according to the present invention, the hypoeutectic composition is obtained. Nevertheless, the reason why primary Si is crystallized is assumed as follows. That is, when a primary casting material having a casting structure in which eutectic Si is crystallized (FIG. 1) is melted in a temperature range of 560 to 580 ° C., a semi-molten state in which α-Al crystals do not melt is obtained. Has a high Si content. In addition, since P serving as a nucleus for crystallization of primary Si is contained in the melt, primary Si is crystallized from the melt during the cooling process from the semi-molten state. It is considered that the Si content in the melt portion has increased to about 13% by weight from the relationship between the Si content and the primary Si crystallization temperature shown in FIG. However, when the heating temperature of the primary casting material exceeds 580 ° C., melting of α-Al crystals starts, and as a result, the Si content in the melt decreases, so that the crystallization amount of primary Si decreases, and Eutectic S
i increases. For this reason, in order to crystallize primary Si which is effective for improving wear resistance, it is necessary to use a primary cast material of 5%.
It is necessary to heat to a temperature range of 60 to 580 ° C. to make a semi-molten state.

[0016] The secondary casting semi-molten primary casting material is die cast or molten forged using a mold having a cavity corresponding to the product shape, and formed into a secondary casting material. At this time, it is preferable to apply a pressure of 500 kg / cm ² or more to the semi-molten primary casting material and press-fit it into a mold, and cool it at 2 ° C./sec or more. The pressurization prevents casting defects such as porosity and shrinkage cavities from occurring in the secondary casting material. Further, since the Al-Si alloy to be cast is in a semi-molten state in which the molten metal is not completely melted and the flow of the molten metal is poor, the pressurization is also effective in filling the molten metal into every corner of the mold cavity. The molten metal cooling rate during the secondary casting affects the structure of the secondary casting material. By increasing the cooling rate to 2 ° C./sec or more, the crystal grains are refined and a dense secondary casting structure effective for improving impact resistance is obtained. In addition, when the molten metal comes in contact with the inner surface of the mold, the solidification shrinkage is prevented by the pressurization, so the heat removal action through the mold works sufficiently, and a dense secondary casting structure is formed inside, resulting in excellent impact resistance. A secondary cast member having good properties is obtained. Further, when the secondary cast member is forged, a forged member having further improved impact resistance can be obtained.

The secondary cast Al-Si alloy is machined as cast material (F material) and can be used as a cast member. If necessary, T6 treatment (490-540 ° C)
× 1 to 6 hours → water cooling → 150 to 180 ° C × 4 to 8 hours →
After increasing the strength by precipitating Mg ₂ Si, AlCu ₂ or the like by air cooling), machining may be performed. Alternatively, it can also be used as a forged part obtained by subjecting F material obtained by secondary casting to warm forging or hot forging and then performing machining. Also in this case, the same T6 treatment as that of the F material may be performed prior to machining. The forging further improves the toughness (impact resistance) of the Al-Si alloy. The Al-S according to the present invention
In the i-alloy, primary crystal Si, which is likely to be the starting point of cracking, is crystallized, so that forging is performed not warm but hot or hot.

[0018]

EXAMPLE After melting various hypoeutectic Al-Si alloys and subjecting them to a molten metal treatment according to a conventional method, the diameter was 45 mm and the height was 25 mm.
And a primary casting material was produced. Table 1 shows the results of investigating the composition of the obtained primary casting material. In addition, three samples were prepared for each of the Al—Si alloys having the same composition, and a sample containing only the primary cast material was treated as a comparative example.

[0019]

Two primary castings of each composition were heated at 570 ° C.
To a semi-molten state by holding for 3 minutes. A pressure of 800 kg / cm ² was applied to a surface of a semi-molten Al-Si alloy having a diameter of 45 mm, and the Al-Si alloy was pressed into a mold having a cavity having a diameter of 85 mm and a height of 7 mm. The Al—Si alloy pressed into the mold was cooled at a cooling rate of about 150 ° C./sec and formed into a secondary casting. A test piece was cut out from one secondary casting material and the microstructure was observed. The results of the observation are shown in Table 2 in comparison with the as-cast primary structure. 1 and 2 show the microstructures of the primary casting material and the secondary casting material for the sample numbers 1-F in Table 1, respectively. In the primary cast material (FIG. 1), fine eutectic Si is dispersed and crystallized at the grain boundaries and the boundaries of dendrite cells, whereas in the secondary cast material (FIG. 2), primary eutectic Si is included in the eutectic Si. Is crystallized.

[0021]

T6 treatment (500 ° C. ×
(3 hours → water cooling → 160 ° C. × 5 hours → air cooling), and two test pieces were cut out and subjected to an abrasion test and a Charpy impact test. In the wear test, surface pressure: 6 MPa,
Sliding speed 1 m / sec, mating material: cast iron, sliding surface roughness: _Ra =
The wear depth of the test piece was measured under the conditions of 1.6 μm, sliding distance: 4 km, lubricant, and test temperature: 80 ° C. The Charpy impact test conformed to JIS. In addition,
The primary cast material subjected to T6 treatment was used as a comparative material. As can be seen from the examination results in Table 3, the materials subjected to the secondary casting and the T6 treatment according to the present invention showed excellent values in both wear resistance and toughness. On the other hand, the comparative material obtained by subjecting the primary cast material to the T6 treatment had an excellent impact value unique to the hypoeutectic Al-Si alloy, but the wear depth was at least 2 mm.
It is as large as 2 μm or more, which indicates that the abrasion resistance is poor.

[0023]

Summarizing the above results, in the hypoeutectic Al-Si alloy targeted by the present invention, primary S
Although no crystallization of i is observed, primary crystal Si having an average particle size of 7.2 to 8.2 μm has an area ratio of 1.8 to 2.8 when secondary casting is performed after the primary casting material is in a semi-molten state. The casting organization was crystallized in%. A comparison of the sample of the present invention obtained by subjecting the secondary cast material to T6 treatment and the sample of the comparative example obtained by subjecting the primary cast material to T6 treatment shows that the Charpy impact value of the sample of the present invention is slightly inferior to that of the comparative sample, With respect to abrasion resistance, the sample of the present invention is remarkably excellent. That is, the obtained Al-
The Si alloy material is a material that maintains excellent toughness peculiar to the hypoeutectic composition and has improved wear resistance due to crystallization of primary crystal Si.

[0025]

As described above, the hypoeutectic Al-Si alloy according to the present invention has the following characteristics:
Utilizing the fact that the i content is locally high, the eutectic Si crystallized portion is selectively melted to a semi-molten state by reheating, and then subjected to secondary casting, whereby the hypoeutectic composition is obtained. , A casting structure in which primary Si was crystallized. The hypoeutectic Al-Si alloy material thus obtained has improved wear resistance due to the crystallized primary crystal Si, and also has excellent impact resistance and toughness unique to the hypoeutectic composition. Therefore, they are used in a wide range of fields as various functional members including shift forks for automobiles.

[Brief description of the drawings]

FIG. 1 shows a hypoeutectic Al—S having a composition specified in the present invention.
Micrograph showing casting structure of i-alloy primary casting material

FIG. 2 shows a hypoeutectic Al—S having a composition specified in the present invention.
Micrograph showing casting structure of i-alloy secondary casting material

FIG. 3 is a graph showing the relationship between the Si content of an Al—Si alloy and the primary Si crystallization temperature.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 30, 1998 (July 7, 1998)
0)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C22C 1/02 503 C22C 1/02 503J (72) Inventor Yukio Kuramasu 1-34, Kambara, Kambara-cho, Anbara-gun, Shizuoka Prefecture No. 1 Nippon Light Metal Co., Ltd. Group Technology Center

Claims (7)

[Claims] 1. Si: 6.5 to 11.0% by weight, P:
0.001 to 0.01% by weight, with the balance being substantially Al. The casting structure obtained by reheating the primary casting material to the solid-liquid coexistence region and performing secondary casting has an average particle size of 6 to 9μ
m-primary crystal Si is dispersed at an area ratio of 1 to 3%, and is hypoeutectic Al-S excellent in impact resistance and wear resistance.
i alloy members. 2. Sr: 0.003 to 0.04% by weight, Sb: 0.05 to 0.25% by weight, Na: 0.00
2. The hypoeutectic Al according to claim 1, comprising one or more of 1 to 0.01% by weight and Ca: 0.001 to 0.02% by weight.
-Si alloy members. 3. Ti: 0.01 to 0.2% by weight,
B: The hypoeutectic Al-Si alloy member according to claim 1, comprising one or more of 0.0001 to 0.04 wt%. 4. The hypoeutectic A according to claim 1,
Cu: 0.2-2% by weight, Mg:
The hypoeutectic Al-Si alloy member according to any one of claims 1 to 3, comprising one or more of 0.2 to 0.7 wt% and Mn: 0.1 to 0.6 wt%. 5. A semi-molten state by reheating a primary cast material obtained by casting a hypoeutectic Al-Si alloy having the composition according to claim 1 to a temperature of 560 to 580 ° C. in a container. Forming a secondary eutectic Al-Si alloy member by press-fitting into a die casting or molten metal forging die. 6. When a semi-eutectic hypoeutectic Al-Si alloy is die-casted or forged, a cooling rate of the semi-molten molten metal is 2 ° C./sec or more, and a pressing force is 500 kg / c.
method for producing a hypoeutectic Al-Si alloy member according to claim 5, wherein the set to m ² or more. 7. A hypoeutectic Al-Si for warm forging or hot forging the secondary cast material obtained by the method according to claim 5 or 6.
A method for manufacturing an alloy member.