WO2008016169A1 - Process for production of aluminum alloy formings, aluminum alloy formings and production system - Google Patents

Abstract

The invention provides a process for production of aluminum alloy formings superior to conventional aluminum alloy forgings in mechanical strength at high temperature. A process for production of aluminum alloy formings by forging a stock consisting of a continuously cast rod made of an aluminum alloy, in which the aluminum alloy contains 10.5 to 13.5% by mass of Si, 2.5 to 6% by mass of Cu, 0.3 to 1.5% by mass of Mg, and 0.8 to 4% by mass of Ni and satisfies the relationship: Ni (% by mass) ≥ [-0.68 × Cu(% by mass) + 4.2(% by mass)] and which comprises the step (82) of preheat treatment of the stock, the heating step (87) of forging the stock, and the step (89) of postheat treatment of an aluminum alloy forming as the heat treatment/heating steps, with the step (82) involving the treatment of keeping the stock at -10°C to 480°C for 2 to 6 hours.

Description

 Description Aluminum-um alloy molded product manufacturing method, aluminum alloy molded product and production system Technical Field

 The present invention relates to a method for manufacturing an aluminum alloy molded article having a forging process using a continuous forged rod made of an aluminum alloy as a raw material, an aluminum alloy molded article, and a production system thereof. Background art

 In recent years, automobiles such as automobiles and motorcycles (hereinafter simply referred to as “automobiles”) have adopted the use of forged aluminum for internal combustion engine pistons in order to improve performance and respond to environmental problems. It has been studied. This is because the driving parts of the internal combustion engine, such as Biston, can be reduced, and the load when the internal combustion engine is operated can be reduced, the output can be improved, and the fuel consumption can be reduced. Forged internal combustion engine pistons made of aluminum alloy have been widely used forged products. However, it is difficult to control internal defects that occur during forged products, and there is a surplus in order to safely design strength. It was necessary to install it, and it was difficult to reduce the weight.

 Therefore, the weight reduction of the biston using aluminum alloy forgings that can suppress the occurrence of internal defects has been studied.

A conventional method for producing a material for forging an aluminum alloy includes a step of preparing a molten aluminum alloy by a normal molten metal manufacturing method, followed by a continuous forging method, a semi-continuous forging method (DC Manufacturing method), forging by any one of so-called continuous forging methods such as hot top forging method, and the like, and producing a lump of aluminum alloy, After that, the mass was subjected to a homogenization heat treatment to homogenize the aluminum alloy crystals. Then, forging is performed on the aluminum alloy forging material (ingot), and further, JIS (Japanese Industrial Standards) T 6 heat treatment is performed, so that an aluminum / nium alloy forged molded product is manufactured.

 Incidentally, the one relating to the 6000 series alloy, in which the temperature of the homogenization heat treatment is suppressed or omitted, is disclosed in JP-A-2002-294383 (Patent Document 1).

 However, Patent Document 1 does not discuss the mechanical characteristics at high temperatures.

On the other hand, the following Japanese Patent Application Laid-Open Publication No. 2005-29054 5 (Patent Document 2) is aimed at making it possible to produce an aluminum alloy molded article having excellent mechanical strength at a higher temperature than conventional aluminum forging. ) Is a method for producing an aluminum alloy molded article having a forging process using a continuous forged rod made of an aluminum alloy as a raw material, and the aluminum alloy has a content of 10.5 mass% to 13.5 mass ⁰ /. Si, 0.15 mass% to 0.6 5 mass%? 6, 2.5% to 5.5% by mass. 11 and 0.3 mass. /. 〜1.5 Containing 5% by mass of Mg, heat treatment consisting of pre-heat treatment process for raw material, heating process for forging process for raw material, post-heat treatment process for aluminum alloy molded product ■ Pre-heat treatment process including heating process A manufacturing method is disclosed which includes a treatment of holding at 2 ° C to 6 hours at ° C to 480 ° C.

 By the way, in recent years, further improvements in efficiency and output of internal combustion engines have been demanded, and as a result, the mechanical strength at higher temperatures has been demanded for the components used there.

Therefore, for aluminum alloy forgings that aim to reduce weight, manufacture of aluminum alloy moldings with improved mechanical strength at higher temperatures (for example, fatigue strength at 350 ° C) than conventional aluminum alloy forgings. A method is sought The

 The present invention has been made in view of the above, and provides a method for manufacturing an aluminum alloy molded article, an aluminum alloy molded article, and a production system that are superior in mechanical strength at higher temperatures than conventional aluminum alloy forging. The purpose is to do. Disclosure of the invention

(1) In order to achieve the above object, according to a first aspect of the present invention, there is provided a method for manufacturing an aluminum alloy molded article having a forging process using a continuous forged rod made of an aluminum alloy as a material. 10.5 mass% to 13.5 mass% Si, 2.5 mass% to 6 mass% Cu, 0.3 mass ⁰ /. ~ 1.5 wt% Mg and 0.8 wt% to 4 wt% Ni, and Ni (wt%) ≥ [-0.6 8 XCu (wt%) +4.2 ( (Mass%)) satisfying the following relational expression, a heat treatment comprising a preheating process for the material, a preheating process for the material before forging, and a post-heat treatment process for the aluminum alloy molded product. (1) It includes a treatment of holding at 10 ° C. to 480 ° C. for 2 hours to 6 hours.

 (2) The second invention of the present invention is characterized in that, in the method for producing an aluminum alloy molded article according to the first invention, the heat treatment temperature in the pre-heat treatment step is 200 ° C to 370 ° C. To do.

 (3) The third invention of the present invention is characterized in that, in the method for producing an aluminum alloy molded article according to the first invention, the heat treatment temperature in the pre-heat treatment step is 110 ° C. to 200 ° C.

 (4) A fourth invention of the present invention is characterized in that, in the method for producing an aluminum alloy molded article of the first invention, the heat treatment temperature in the pre-heat treatment step is 370 ° C. to 480 ° C.

(5) The fifth invention of the present invention is the aluminum alloy of the first to fourth inventions described above. In the method for producing a molded article, the post-heat treatment step is maintained at 170 ° C. to 230 ° C. for 1 hour to 10 hours without performing a solution treatment.

 (6) According to a sixth invention of the present invention, in the method for producing an aluminum alloy molded article according to any one of the first to fifth inventions, the aluminum alloy contains 0.15% by mass to 0.65% by mass of Fe, It is characterized by that.

 (7) A seventh invention of the present invention is the method for producing an aluminum alloy molded article according to the first to sixth inventions, wherein the aluminum alloy contains 0.003 mass% to 0.02 mass% of P. It is characterized by that.

(8) The eighth invention of the present invention is the method for producing an aluminum alloy molded article according to the first to seventh inventions, wherein the aluminum alloy is 0.003 mass% to 0.03 mass ⁰ /. Sr, 0.1 mass% to 0.35 mass% 313, 0.0005 mass ⁰ /. It is characterized by containing any one kind or a combination of two or more kinds of ˜0.015 mass% Na and 0.001 mass% ˜0.02 mass% Ca.

(9) Ninth aspect of the present invention is the manufacturing method of an aluminum alloy molded product of the first invention to eighth invention, the aluminum alloy, 0.1 wt% to 1. 0 mass _^0/0 of Mn, 0.05 wt% to 0. 5 wt% of 〇 1 :, 0.04 wt% to 0. 3 mass _^0/0 Z r, 0. 01 wt% to 0. 1 5 wt% of V, 0. 01 wt% to 0. including any one or more combinations of a 2 wt _^0/0 T i, characterized in that.

 (10) According to a tenth aspect of the present invention, in the method for producing an aluminum alloy molded article according to any one of the first to ninth aspects, the processing rate of a portion requiring high temperature fatigue strength in the forging step is 90%. It is the following, It is characterized by the above-mentioned.

 (1 1) The first invention of the present invention is the method for producing an aluminum alloy molded article according to the first invention to the tenth invention, wherein the preheating temperature before processing in the forging process is 380 ° C. to 480 ° It is C.

(12) The first invention of the present invention is the aluminum of the first invention to the first invention. In the method of manufacturing a molded alloy product, a continuous forging rod is made of an aluminum alloy with an average molten metal temperature of liquidus + 40 ° C to + 230 ° C, and a forging speed of 80 (mm / min) to 2 It is obtained by forging by a continuous forging method at 000 (mm / min).

 (1 3) The first invention of the present invention is an aluminum alloy molded product manufactured by any one of the above-described methods for manufacturing an aluminum alloy molded product of the first to first inventions. A network structure of crystallized substances or acicular crystallized substances or aggregates of crystallized substances formed at the time of continuous fabrication in the structure partially remain after molding and heat treatment. To do.

 (14) A fourteenth aspect of the present invention is an aluminum alloy molded article produced by any one of the above-described methods for producing an aluminum alloy molded article of the first to the first inventions. Eutectic S i area occupancy is 8% or more, eutectic S i average particle size is 5 μπι or less, eutectic S i needle ratio 1. The area occupation ratio is 1.2% or more, the average particle size of the intermetallic compound is 1.5 m or more, the length of the intermetallic compound or the length of the aggregate of the intermetallic compounds in contact is 3 / im or more. 30% or more.

 (15) The 15th invention of the present invention is the aluminum alloy molded product of the 13th invention or the 14th invention formed as an engine alloy made of aluminum alloy having a crown surface portion and a skirt portion. The high-temperature fatigue strength of the crown surface portion is 5 OMPa or more.

 (16) The sixteenth invention of the present invention is a production system in which a series of processes from a molten metal to an aluminum alloy molded product is constructed as a continuous line, wherein the aluminum alloy of the first invention to the first invention is used. The method includes any one of the manufacturing methods of the molded product.

According to the first invention described in (1), the aluminum alloy is made of Si, Cu, Mg and Since Ni is contained, it is possible to obtain a molded article having high-temperature fatigue strength and good forgeability, ductility, and toughness. Further, the composition of the N i and Cu, N i (mass _^0/0) ≥ [one 0. 68 X Cu (mass%) +4. 2 (wt%)] Since satisfying the relational expression, at higher temperatures The fatigue strength characteristics of the steel are improved.

 Conventionally, it has been necessary to make a prototype of a molded product from various levels of alloy by changing the alloy composition, and because the evaluation of high temperature fatigue strength requires complicated equipment and a lot of time, In particular, it has been difficult to design an alloy having fatigue strength at high temperatures.

 By designing the alloy composition using the above relational expression of the present invention as an index, it is possible to easily obtain an alloy having fatigue strength characteristics at a higher temperature, and from 350 ° C. An aluminum alloy molded product having excellent mechanical strength can be obtained even at high temperatures.

 More specifically, for example, the fatigue strength at 350 ° C after holding at 350 ° C for 100 hours is 33 MPa or more. These characteristics are, for example, characteristics required for the crown portion of the internal combustion engine piston that is in contact with a high-temperature atmosphere. Therefore, by using the aluminum alloy molded article of the present invention, it is possible to make the wall thinner than the conventional internal combustion engine piston, and it is possible to reduce the weight of the internal combustion engine piston. In addition, it is possible to answer the weight reduction demanded by the market, and to realize a reduction in fuel consumption and an increase in output of the internal combustion engine.

 According to the second invention described in (2), since the heat treatment temperature in the pre-heat treatment step is set to 200 ° C to 370 ° C, the high temperature fatigue strength and forgeability, ductility, and toughness are more balanced. Thus, a better molded product can be obtained.

 According to the third invention described in (3), since the heat treatment temperature in the pre-heat treatment step is set to 10 ° C. to 20 ° C., a molded article with better high-temperature fatigue strength can be obtained. However, the forgeability, ductility and toughness are lower than those with heat treatment temperatures of 200 ° C to 370 ° C.

According to the fourth invention described in (4), the heat treatment temperature in the pre-heat treatment step is 370 ° C to 4 ° C. Since the temperature is set to 80 ° C., it is possible to obtain a molded product having better forgeability, ductility, and toughness. However, the high-temperature fatigue strength is lower than that at a heat treatment temperature of 200 ° C to 370 ° C.

 According to the fifth invention described in (5), the high temperature fatigue strength is better because it is maintained at 170 ° C to 230 ° C for 1 hour to 10 hours without performing solution treatment in the post heat treatment step. A favorable molded product can be obtained. However, the ductility and toughness are lower than those obtained after solution treatment and maintained at 170 to 230 ° C for 1 to 10 hours.

 According to the sixth invention described in (6), since the aluminum alloy contains 0.15 mass% to 0.65 mass% of e, the A 1—F e system and the A 1—F e—Si system And A 1—N i _F e particles are crystallized to improve high-temperature mechanical strength. The Fe content of 0.15 mass% to 0.65 mass% suppresses an increase in coarse crystals, and improves forgeability, high temperature fatigue strength, and toughness.

 According to the seventh invention described in (7), since the aluminum alloy contains 0.003 mass% to 0.02 mass% of P, P generates primary crystal Si and gives priority to wear resistance. Further, P has an effect of refining the primary crystal Si, and functions to suppress a decrease in forgeability, ductility and high temperature fatigue strength due to the generated primary crystal Si. And the content of 0.03 mass% to 0.02 mass% of soot suppresses the increase of coarse primary crystals Si, and improves forgeability, high temperature fatigue strength, and toughness.

According to the eighth invention described in (8), the aluminum alloy is 0.003 mass ⁰ /. ~ 0.03 mass% 3]: 0.1 mass% ~ 0.35 mass% 315, 0.005 mass% ~ 0.01 5 mass% Na, 0.00 1 mass% ~ 0 02% by mass. Since one or a combination of two or more of & is included, the generation of primary crystals Si can be suppressed, which is preferable when forgeability, ductility, and toughness are prioritized. And the contents of Sr, Sb, Na, and Ca in this range suppress the generation of primary crystals Si and improve forgeability, toughness, and high-temperature fatigue strength.

According to the ninth invention described in (9), the aluminum alloy is 0.1 mass% to 1. 0% by mass 1 \ 111, 0.05% by mass to 0.5% by mass ○]: 0.04% by mass to 0.3% by mass Zr, 0.0 1% by mass to 0.15% Since it includes one or more combinations of V 1% by mass, 0.0 1% by mass to 0.2% by mass Ti, or A 1— Mn system or A 1— F e -Mn- S i, A 1 —C r, A 1 —F e— C r—S i, A 1—Z r, k \ HA 1—T i compounds are crystallized or precipitated. Improves the high temperature mechanical strength of rum alloys. And the contents of Mn, Cr, Zr, V and Ti in this range suppress the increase of coarse crystals and improve forgeability, high temperature fatigue strength and toughness.

 According to the tenth aspect of the invention described in (10), since the processing rate of the portion requiring high-temperature fatigue resistance in the forging process is reduced to 90% or less, the network structure or needle of the crystallized product Since the texture and aggregates are appropriately divided and remain moderately, a molded product having good ductility, toughness and high-temperature fatigue strength can be obtained.

 (1 1) According to the first invention described in (1 1), since the preheating temperature before processing in the forging process is set to 380 ° C to 480 ° C, high temperature fatigue strength, forgeability, ductility, and toughness are achieved. A good molded product can be obtained.

 According to the first and second inventions described in (1 2), the average temperature of the molten metal is a liquidus + 40 ° C to + 230 ° C, and the forging speed is 80 (mm / min) to 2000 (mm / min) and forging by a continuous forging method to obtain a continuous forging rod, a uniform and fine crystallized network structure, needle-like structure and aggregate are obtained, and high-temperature fatigue strength and forgeability, A molded product with good ductility and toughness can be obtained.

 According to the first and third inventions described in (1 3), the network structure of the crystallized product or the acicular crystallized product or the aggregate of crystallized product formed during continuous forging in the structure is partly formed after molding and heat treatment. Therefore, it is possible to obtain a molded article having high-temperature fatigue strength and good forgeability, ductility, and toughness.

According to the fourteenth invention described in (14), the area occupancy of the eutectic Si is 8% or more, The average particle size of crystal Si is 5 μm or less, the eutectic Si needle shape ratio is 1.4 or more, 25% or more, the area occupation ratio of intermetallic compounds is 1.2% or more, The average particle size is 1.5 μm or more, the length of intermetallic compounds or the length of the aggregate of intermetallic compounds in contact is 3 / m or more is 30% or more. It is possible to more reliably obtain a molded article having good properties, ductility, and toughness.

 According to the fifteenth aspect of the invention described in (15), since the high temperature fatigue strength of the crown surface portion is 5 OMPa or more, the crown surface portion of the internal combustion engine piston has a sufficient high temperature fatigue strength. Etc. can be used suitably.

 According to the sixteenth aspect of the invention described in (16), a series of processes from the molten metal to the aluminum alloy molded product is constructed as a continuous line, and at least the process includes the production of any one of the aluminum alloy molded products described above. Since the method includes a process, fatigue strength characteristics at higher temperatures are improved.

 In the past, it was necessary to make a prototype of a molded product from a multi-level alloy by changing the alloy composition, and the evaluation of high temperature fatigue strength was also an evaluation requiring complicated equipment and a lot of time. Designing alloys with fatigue strength at high temperatures has been difficult.

 However, by designing the alloy composition using the above relational expression of the present invention as an index, it is possible to easily obtain an alloy having fatigue strength characteristics at a higher temperature, and at a temperature higher than 3500 ° C. Even at that time, an aluminum alloy molded product having excellent mechanical strength can be obtained.

More specifically, for example, the fatigue strength at 35 ° C. after holding at 350 ° C. for 100 hours is 33 MPa or more. These characteristics are, for example, the characteristics required for the crown surface portion of the internal combustion engine piston in contact with the high temperature atmosphere. Therefore, by using the aluminum alloy molded product of the present invention, it is possible to reduce the thickness of the conventional internal combustion engine piston, and to reduce the weight of the internal combustion engine piston. And it can answer the weight reduction demanded by the market, and achieves reduction in fuel consumption and output of internal combustion engines. be able to. Brief Description of Drawings

 FIG. 1 is a view showing a forging production system which is an example of a production line for realizing the production process of the present invention.

 FIG. 2 is a diagram showing an example of the vicinity of the vertical shape of the continuous forging apparatus used in the present invention. FIG. 3 is a view showing another example of the vicinity of the vertical shape of the continuous forging apparatus used in the present invention.

 FIG. 4 is a view showing the effective mold length of the continuous forging apparatus used in the present invention. FIG. 5 is a view showing another example of the continuous forging apparatus used in the present invention.

 FIG. 6 is a diagram for explaining the relationship between the content ratios of Ni and Cu in an aluminum alloy.

 FIG. 7 (a) is a plan view of a piston having the shapes of Examples 17 and 18 and Comparative Examples 11 to 13 of the present invention. Fig. 7 (b) is a front view of the piston shown in Fig. 7 (a).

 FIG. 8 is a cross-sectional view taken along the line M-VDI of FIG. 7 (a). BEST MODE FOR CARRYING OUT THE INVENTION

 The alloy composition of the molded article of the present invention will be described.

 The molten aluminum alloy used in the present invention ranges from 10.5 mass% to 1 3.

5 mass% (preferably 11.5 mass% to 13 mass ⁰ /.) Si, 2.5 mass% to 6 mass% (preferably 3.5 mass% to 5.5 mass%) Cu , 0.3 mass. /. ~ 1.5 wt% (preferably 0.5 wt% to 1.3 wt%) Mg, 0.8 wt% to 4 wt% (preferably 1.8 wt% to 3.5 wt%) N It includes i, and N i (mass ⁰⁾ ≥ [one 0. 68 XC u (mass _^0/0) + AA (mass _^0/0)] (where, AA is a constant AA 4.2, preferably AA≥4.7. The composition is adjusted to satisfy the following relational expression.

Si increases the high-temperature mechanical strength and wear resistance due to the distribution of eutectic S i, and coexists with Mg to precipitate Mg ₂ Si particles and improve the high-temperature mechanical strength. If the Si force is less than 1 0.5% by mass, the above effect is small. If it exceeds 13.5% by mass, the crystallization of the primary crystal Si increases and the high-temperature fatigue strength, ductility and toughness are reduced.

 N i generates A 1−N i and A 1 _N i _Cu crystals, thereby improving the high-temperature mechanical strength. If the Ni force is less than 0.8% by mass, the above effect is small, and if it exceeds 4% by mass, coarse crystals increase and forgeability, high-temperature fatigue strength, ductility, and toughness decrease.

Cu precipitates Cu A 1 ₂ particles, and further generates crystallized A 1—Cu and A 1—Ni—Cu crystals, improving the high-temperature mechanical strength. When Cu is less than 2.5% by mass, the above effect is small. When it exceeds 6% by mass, coarse crystals of A 1-1 Cu system increase and forgeability, high temperature fatigue strength, ductility, and toughness decrease. Let

Mg coexists with Si and precipitates Mg ₂ Si particles to improve high-temperature mechanical strength. When Mg is less than 0.3% by mass, the above effect is small, and when it exceeds 1.5% by mass, coarse crystals of Mg ₂ Si increase and forgeability, high-temperature fatigue strength, ductility, and toughness are reduced. Let me down.

Further, in the present invention, N i and C composition u is N i (wt%) ≥ [one 0. 68 XC u (mass _^0/0) + AA (mass _^0/0)] (where, AA is a constant Therefore, it is necessary to satisfy the relational expression AA 4.2, preferably AA≥4.7. This is because the fatigue strength characteristics at higher temperatures are improved when Ni and Cu satisfy this relational expression. An aluminum alloy molded article prepared so that the constant AA is 4.7 or more is preferable because the amount of network-like or acicular intermetallic compounds that contribute to high-temperature strength increases. The mechanism for improving the fatigue strength characteristics described above is not clear, but can be estimated as follows. What contributes most to the improvement of high-temperature mechanical strength is the 8 1-1 ^ 1 system, A 1 1 N i—C u, A 1—C u system crystallized materials and aluminum fabric under high temperature environment. It is thought that Cu is a solid solution. The relationship between the amount of Cu and the amount of Ni that effectively increases the high-temperature mechanical strength due to the solid solution of these crystals and Cu was derived from the above equation.

 A molded article using such an aluminum alloy has a fatigue strength at 350 ° C, which is a preferable value, of 33 MPa or more, and more preferably 43 MPa or more. Furthermore, the fatigue strength at 300 ° C is 55 MPa or more.

The molten metal, M n of 0.1 wt% to 1 wt% (preferably 0.2% to 0.5 mass _^0/0), 0.05 weight ⁰ /. ~ 0.5 wt% (preferably 0.1% to 0.3 mass _^0/0) Noji, 0.04 wt% to 0. 3% by weight (preferably 0.1% to 0.2 mass _^0/0) of Z r, 0.0 1 wt% to 0. 1 5 mass _^0/0 (preferably 0.05 mass% to 0. V 1 wt%), 0.0 1 wt% to 0 It is preferable to contain one or more of 2 mass% (preferably 0.02 mass% to 0.1 mass%) of Ti. The contents of Mn, C r, Z r, V, and T i include A 1—M n system, A 1—F e—M n—S i system, A l—C r system, and A 1—F e— C. rSi-based, Al-Zr-based, Al-V-based, and A1-Ti-based compounds crystallize or precipitate, improving the high-temperature mechanical strength of the aluminum alloy. Mn of 0.1 less than 1 mass%, C r is 0.5 less than 0 5 wt ° / _0, Z r is 0.1 less than 04 wt%, V is 0.0 less than 1 wt%, T i is 0. 0 1 Quality When the amount is less than% by mass, the above effect is small, Mn exceeds 1.0% by mass, Cr exceeds 0.5% by mass, ：: exceeds 0.3% by mass, and V is 0.15% by mass. When Ti exceeds 0.2% by mass, coarse crystallization increases and forgeability, high temperature fatigue strength, and toughness decrease.

Further, F e a 0.1 5 wt% to 0. 65 wt% preferably comprises (preferably 0.3% to 0.5 mass _{^{0/0), A 1-}} F e system and A 1-F e—S i system or A 1 1. Crystallize Ni-Fe particles to improve high-temperature mechanical strength. When Fe is less than 0.15% by mass, the above effect is small. When it exceeds 0.65% by mass, the A 1—F e system, A 1 -F e -S i system, or A 1—N i _F e The coarse crystals of the system increase and the forgeability, high temperature fatigue strength, ductility, and toughness decrease.

 Also, P is 0.003 mass% to 0.02 mass% (preferably 0.007 mass%

~ 0.01 6% by mass). P generates primary crystal S i and is therefore preferred when wear resistance is prioritized, and has the effect of refinement of primary crystal S i, and the forgeability, ductility, and high-temperature fatigue strength of the generated primary crystal S i are high. It works to suppress the decline. If P is less than 0.003 mass%, the effect of refining primary crystal 3 i is small, and coarse primary crystal S i is generated at the center of the ingot, reducing forgeability, high-temperature fatigue strength, ductility, and toughness. When P exceeds 0.02 mass%, the generation of primary crystals Si increases and forgeability, high temperature fatigue strength, ductility, and toughness deteriorate.

Further, 0.003% to 0.03% by mass (preferably 0.01% by mass to 0.02% by mass) 31: 0.1% by mass to 0.35% by mass (preferably 0.00% by mass). 1 5 wt% to 0. S b of 25 wt%), 0.0005 wt% to 0. 0 1 5 mass _^0/0 (preferably 0.00 1 wt% to 0. Na, 01 mass%) 0 .00 1 mass% to 0.02 mass ⁰ /. It is preferable to contain one or more of Ca (preferably 0.005 mass% to 0.0 1 mass%) because of the effect of refining the eutectic Si. When S r is less than 0.003 mass%, S b force S is less than 0.1 mass%, N a is less than 0.0005 mass%, and C a is less than 0.001 mass%, the above effects are small, and S r Is greater than 0.03 mass%, 313 is greater than 0.35 mass%, Na is greater than 0.01 mass%, and Ca is greater than 0.02 mass%. Forging defects occur, reducing forgeability, high-temperature fatigue strength, and toughness.

The composition ratio of the alloy components of the aluminum alloy molded product and the ingot lump is, for example, a photoelectric photometric emission spectroscopic analyzer as described in JISH 1 305 (Example: Shimadzu) It can be confirmed by the method according to Sakusho PDA—5 5 0 0).

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

 FIG. 1 is a diagram showing a production system that is an example of a production line that realizes the production process of the present invention. In Fig. 1, the forged product production system consists of a continuous forging device 8 1 that horizontally forges a continuous forging bar from a molten metal and cuts it to a predetermined length, and a continuous forging forged by this continuous forging device 8 1. Pre-heat treatment device 8 2 for heat treatment of the rod, and straightening device 8 3 for correcting the bending of the continuous forged rod when the continuous forged rod is bent by heat treatment in this pre-heat treatment device 8 2, and this straightening device 8 It is necessary to forge the molded product with the peeling device 8 4 that removes the outer peripheral part of the continuous forged bar whose curvature has been corrected in step 3 and the continuous forged bar whose outer peripheral part has been removed with the peeling device 8 4. A cutting device 8 5 for cutting into length-cut pieces, an upsetting device (not shown) for preheating and cutting the cut pieces cut by the cutting device 85, and this upsetting device Element that has been pre-heated to cover the upset material with lubricant Lubricator 8 6 A, 8 6 B and a lubricant heated by pre-heater 8 7 are attached to the material which is coated or preheated with graphite lubricant. Forging device 8 8 forging forged products (molded material) from the processed material, and post-heat treatment device 8 9 for subjecting the forged product (forged product) forged with this forging device 8 8 to post-heat treatment 8 9 Has been.

 The post heat treatment apparatus 8 9 includes, for example, a solution heating apparatus 90 that performs solution treatment on the forged product, a quenching apparatus 9 1 that quenches the forged product heated by the solution heating apparatus 90, and this quenching apparatus. An aging treatment device 9 2 that performs aging treatment on the forged product quenched by the charging device 9 1 can be used. When the solution treatment is omitted, it is preferable not to provide the solution heating apparatus 90 and the quenching apparatus 91 but to provide the aging treatment apparatus 92 after the forging apparatus 88.

The peeling device 84 and the upsetting device can be omitted. In addition, transfer between each device can be performed by an automatic transfer device. Lubricators 8 6 A, 8 6 B Lubricant coating treatment can be replaced with bonder (phosphate coating treatment) equipment 8 6 C.

 Here, the pre-heat treatment apparatus 8 2 has a function of holding the material temperature at 110 ° C. to 48 ° C. for 2 hours to 6 hours. The preheating device 87 has a function of setting the material temperature to 3800 ° C. to 48 ° C. Post-heat treatment equipment 8 9 solution heat-heating equipment 90 and quenching equipment 9 1 are quenched after the temperature for solution treatment of forged products (molded products) is set to 48 0 ° C to 5 20 ° C It has a function to do. The aging treatment device 9 2 of the post heat treatment device 89 has a function of maintaining the temperature of the forged product (molded product) at 1700 ° C. to 230 ° C.

 The production method using the production system of the present invention is a method in which a round bar obtained by forging an aluminum alloy by a continuous forging method is subjected to a pre-heat treatment, and the pre-heat-treated material is used as a raw material by hot plastic working. And a post-heat treatment step after plastic working, wherein the temperature of the pre-heat treatment is 10 to 48 ° C., and the material temperature during hot plastic working In the post-heat treatment process, solution heat is applied directly to the material temperature from 48 ° C to 52 ° C or without solution treatment. The temperature is controlled so as to satisfy the temperature conditions from 1700 ° C to 230 ° C, and the molded products are manufactured consistently from the forging process to each heat treatment process. As a result, a molded product having preferable mechanical strength can be stably produced.

 The force that can give a forging process as the plastic process. The manufacturing method of the present invention is a rolling process as long as it satisfies the conditions of the pre-heat treatment temperature, the material temperature during hot plastic working, and the post-heat treatment temperature. It can also be combined with extrusion. This is because, in any case, the effects of the present invention can be obtained in controlling the network of tissue crystals.

The aluminum alloy molded article of the present invention can be suitably used as a part that requires mechanical strength at high temperatures. For this reason, for example, molded products such as engine pistons, valve lifters, valve retainers, and cylinder liners are The molded product can be manufactured into a desired shape by further machining on a lathe, machining center, etc. as necessary, and used as a part for various products.

 For the basic solidification method part of the production method used in the present invention, any of the known hot top continuous forging method, vertical continuous forging method, horizontal continuous forging method, and DC forging method should be used. Can do. For example, one or two or more fluids selected from gas, liquid lubricant, and thermally decomposed gas on the inner wall surface of a cylindrical bowl with forced cooling held so that the central axis is in the horizontal direction A columnar metal melt is formed by supplying a molten aluminum alloy containing Si to one end of the cylindrical saddle mold, and the soot mass formed by solidifying the columnar metal melt in the cylindrical saddle mold is formed. It can be a horizontal continuous forging method in which it is pulled out from the other end of the cylindrical saddle type. Below, the case where this invention is applied to the horizontal continuous forging method is demonstrated.

 FIG. 2 is a view showing an example of the vicinity of the vertical shape of the continuous forging apparatus used in the present invention. Tundish 2 5 0, refractory so that molten alloy 2 5 5 stored in tundish 2 5 0 is supplied to cylindrical saddle 2 0 1 via plate 2 1 0 made of refractory A product-made plate-like body 2 1 0 and a cylindrical saddle shape 2 0 1 are arranged. The cylindrical saddle mold 20 1 is held so that the saddle mold central axis 2 2 0 is substantially horizontal. Forced cooling means is provided inside the cylindrical bowl 2 0 1 so that the molten alloy 2 5 5 becomes the solidified lump 2 1 6, and solidified lump 2 1 6 is provided at the outlet of the cylindrical bowl 2 0 1. The forced cooling means is provided. In FIG. 2, a cooling water shower device 205 is provided as an example of means for forcibly cooling the solidified slag 2 16. A drive unit (not shown) is installed near the outlet of the cylindrical saddle mold 20 1 so that the solidified clot 2 1 6 that has been forcibly cooled is drawn out at a constant speed and continuously produced. Has been. Furthermore, a synchronous cutting machine (not shown) for cutting the drawn forged bar into a predetermined length is provided.

Another example of the vicinity of the saddle shape of the apparatus used in the present invention will be described with reference to FIG. Fig. 3 shows a schematic cross-sectional view of an example of a DC forging machine. This DC forging machine In this case, the molten aluminum alloy 1 is introduced into the fixed water-cooled mold 5 made of aluminum alloy or copper via the pot 2, the dip tube 3 and the float distributor 4. The water cooling mold 5 is cooled by cooling water 5A. The molten aluminum alloy 6 introduced into the water-cooled mold 5 shrinks by forming a solidified shell 7 at the portion in contact with the water-cooled mold 5, and the solidified aluminum alloy mass 7 A is cooled by the lower mold 9 with the water-cooled mold 5. Pulled down from. At this time, the aluminum alloy ingot 7 A is further cooled by the water cooling jet 8 supplied from the water cooling mold 5 and is completely solidified. When the lower end 9 where the lower mold 9 can move is reached, the aluminum alloy ingot 7A is cut at a predetermined position and taken out.

 Returning to FIG. 2, the description will be continued. The cylindrical bowl 20 1 is held so that the bowl center axis 2 2 0 is almost horizontal (in the shape), and in the bowl cooling water cavity 2 0 4 By cooling the vertical wall surface with cooling water 2 0 2, the columnar molten metal 2 1 5 filled in the cylindrical vertical wall 2 0 1 is removed from the surface contacting the vertical wall and solidified on the surface. Cooling water shower device 2 0 for forced cooling means of cylindrical bowl 20 1 that forms a shell, and solidified slag 2 1 6 at the outlet end of cylindrical bowl 20 1 This is a cylindrical saddle mold 201 having a forced cooling means for discharging cooling water from 5 to solidify the columnar metal melt 2 15 in the cylindrical saddle mold 210. Further, the cylindrical saddle mold 20 1 is connected to the tundish 2 5 0 through a refractory plate-like body 2 1 0 at one end opposite to the jet port of the cooling water shower device 2 0 5. .

 In FIG. 2, the cooling water for forced cooling of the cylindrical bowl 20 1 and the cooling water for forced cooling of the solidified lumps 2 1 6 are supplied through the cooling water supply pipe 20 3. Power S can be supplied separately for each.

From the position where the extension line of the central axis of the jet outlet of the cooling water shower device 2 0 5 hits the surface of the solidified lump 2 1 6, the cylindrical saddle shape 2 0 1 and the refractory plate 2 1 0 The length to the contact surface is called the effective mold length (see symbol L in Fig. 4), and 1 5 πιπ! ~ 70 m m is preferred. If this effective mold length is less than 15 mm, it is impossible to forge because a good film is not formed, and if it exceeds 7 Omm, there is no effect of forced cooling, and solidification by the vertical wall dominates and the cylindrical vertical mold 2 0 1 and molten columnar metal 2 1 5 or the contact resistance with the solidified shell increases, causing cracks in the skin, and tearing at the inner part of the cylindrical saddle 20 1 Since it becomes stable, it is not preferable.

 The material of the cylindrical saddle mold 201 is preferably one or a combination of two or more selected from aluminum, copper, or alloys thereof. A combination of materials can be selected in terms of thermal conductivity, heat resistance, and mechanical strength.

 Further, it is preferable that the cylindrical bowl-shaped mold 201 is a bowl-shaped mold in which a permeable porous material 2 2 2 having a self-lubricating property is loaded in a ring shape on the surface in contact with the columnar molten metal 2 15. . The ring shape is a state in which the inner surface 2 2 1 of the cylindrical saddle 201 is attached to the entire circumferential direction. The permeability of the permeable porous material 2 2 2 is 0.005 [L (liter) / (cm2 / min)] to 0.03 [L / (c 2 / min)], more preferably 0.0. 7 [L / (cm2 / min)] to 0.02 [L / (cm2 / min)) is preferable. The thickness of the permeable porous material 2 2 2 to be attached is not particularly limited, but 2 mn! ˜1 Omm, more preferably 3 mm to 8 mm. For example, graphite having an air permeability of 0.008 [L / (c m2 / min)] to 0.0 1 2 [L / (c m2 / min)] is used as the permeable porous material 2 2 2. Can be used. Here, the air permeability is measured by measuring the air flow rate per minute of air with a pressure of 2 kgZ cn ^ on a test piece with a thickness of 5 mm.

 5 πιπ of the effective monoredo length! ~ 15 mm infiltration '1 "cylindrical saddle 20 1 fitted with raw porous material 2 2 2 is preferably used. Cylindrical saddle 20 1, refractory plate 2 10 It is preferable to place an O-ring 2 1 3 on the mating surface of the permeable porous material 2 2 2.

The shape of the inner wall surface 2 2 1 of the radial cross section of the cylindrical bowl 2 0 1 is triangular, in addition to the circular shape. It may be a shape, a rectangular cross-sectional shape, or a shape having an irregular cross-sectional shape having no symmetry axis or symmetry plane. Alternatively, in the case of forming a hollow gob mass, a core holding a core inside the saddle shape may be used. The cylindrical saddle mold 20 1 1 is a cylindrical saddle mold with both ends open, and is formed from one end through a pouring port 2 1 1 drilled in the refractory plate-like body 2 10 1. The molten alloy 2 5 5 enters the inside of the bowl mold 20 1, and the solid clot 2 1 6 is pushed out or pulled out from the other end.

 The inner wall surface 2 2 1 of the cylindrical saddle mold 2 0 1 faces the vertical axis of the bowl 2 2 0 in the direction of pulling out the solidified lump 2 1 6 0 to 3 degrees, more preferably 0 to 1 degree It is formed at an elevation angle of. If the elevation angle is less than 0 degree, the solidified clot 2 1 6 is not able to be forged because it receives resistance at the outlet of the cylindrical bowl 2 0 1 when it is pulled out of the cylindrical bowl 2 0 1, while it exceeds 3 degrees And the inner wall surface 2 2 1 of the cylindrical bowl 2 0 1 is insufficiently in contact with the molten metal 2 1 5, and the molten metal 2 1 5 and the solidified shell to the cylindrical bowl 2 0 1 Solidification becomes insufficient due to the reduced heat removal effect. As a result, remelted skin may occur on the surface of the solidified lumps 2 16, or it may lead to smoldering traps such as the unsolidified molten alloy 2 5 5 ejecting from the ends of the cylindrical saddle mold 2 0 1. Since it becomes high, it is not preferable.

 The tundish 2 5 0 is supplied to the molten metal inflow part 2 5 1, the molten metal holding part 2 5 2, and the cylindrical vertical mold 2 0 1 that receives the molten aluminum alloy adjusted to the specified alloy composition by an external melting furnace, etc. Outflow part 2 5 3 The tundish 2 5 0 maintains the liquid level 2 5 4 of the molten metal 2 5 5 at a position higher than the upper surface of the cylindrical mold 2 0 1, and in the case of multiple frames, each tubular shape The molten alloy 2 5 5 is stably distributed to the vertical mold 2 0 1. Molten metal holding part 2 5 2 in tundish 2 5 0 2 5 5 is a molten metal plate 2 5 5 is a pouring hole provided in a refractory plate 2 1 0 2 1 1 to a cylindrical bowl 2 0 1 Be poured into hot water.

The refractory plate-like body 2 1 0 is for separating the tundish 2 5 0 and the cylindrical bowl 2 1 0 1 and can be made of a material having fire and heat insulation, Example For example, Lumi board manufactured by Etias Co., Ltd., Insular manufactured by Foseco Co., Ltd., and fiber blanket board manufactured by Ibiden Co., Ltd. may be mentioned. The refractory plate-like body 2 1 0 has such a shape that the pouring port 2 1 1 can be formed. One or more pouring spouts 21 1 1 can be formed on the part where the refractory plate-like body 2 10 1 protrudes inward from the inner wall surface 2 2 1 of the cylindrical saddle mold 2 0 1.

 Reference numeral 20 8 denotes a fluid supply pipe for supplying a fluid. Lubricating fluid can be listed as the fluid. The fluid may be any one or two or more fluids selected from gas and liquid lubricant. It is preferable to separately provide gas and liquid lubricant supply pipes. .

 The fluid pressurized and supplied from the fluid supply pipe 2 0 8 passes through the annular passage 2 2 4 and is supplied to the gap between the cylindrical basket 2 0 1 and the refractory plate-like body 2 1 0. It is preferable that a gap of 200 Aim or less is formed in a portion where the cylindrical saddle mold 20 1 faces the refractory plate-like body 2 10. This gap is so large that the molten alloy 2 5 5 cannot be inserted, and the fluid can flow out to the inner wall surface 2 2 1 of the cylindrical mold 2 0 1. In the form shown in FIG. 2, the annular passage 2 2 4 is perforated on the outer peripheral surface side of the permeable porous material 2 2 2 attached to the cylindrical saddle mold 20 1, and the fluid is applied to it. Pressure penetrates the inside of the permeable porous material 2 2 2 and is sent to the entire surface of the permeable porous material 2 2 2 in contact with the molten columnar alloy 2 1 5 Supplied to 2 2 1 The liquid lubricant is heated to be decomposed gas and may be supplied to the inner wall surface 2 21 of the cylindrical saddle mold 20 1.

 As a result, it is possible to improve the lubrication between the permeable porous surface of the cylindrical saddle mold 201 and the outer peripheral surface of the columnar molten metal 2 15 and the outer peripheral surface of the solidified shell. By mounting the permeable porous material 2 2 2 in a ring shape, a better lubrication effect can be obtained, and an aluminum alloy continuous mirror rod can be easily fabricated.

The corner space 230 is formed by any one or two or more kinds selected from the supplied gas, liquid lubricant, and gas decomposed from the liquid lubricant. The forging process included in the production method of the present invention will be described.

 In FIG. 2, the molten alloy 255 in the tundish 250 passes through the refractory plate 210, and is supplied to the cylindrical bowl 201 held so that the bowl central shaft 220 is substantially horizontal. It is forcibly cooled at the outlet of the cylindrical bowl 201 and becomes a solidified lump 21 6. Since the solidified lumps 2 16 are pulled out at a constant speed by a driving device installed near the outlet of the cylindrical mold 201, they are continuously formed into a forged bar. The drawn forged bar is cut into a predetermined length by a synchronous cutting machine. That is, the continuous forging rod is made of an aluminum alloy whose average temperature of molten alloy 255 is liquidus + 40 ° C to + 230 ° C, and the forging speed is set to 300 (mm / min) to 2000 (mm / min). Forged by a continuous forging method. Within this condition range, the crystallized product is finely dispersed, resulting in a molded product having excellent forging formability and excellent high-temperature mechanical strength. In the case of the hot top continuous forging method, the vertical continuous forging method and the DC forging method, a forging speed of 80 (mm / min) to 400 (mm / min) is preferable. Therefore, the forging speed is preferably 80 (mm / m η) to 2000 (mm / min).

 The composition of the molten aluminum alloy 255 stored in the tundish 250 will be described.

The molten alloy 255 has a Si of 10.5 mass% to 13.5 mass% (preferably 11.5 mass% to 13 mass%), 2.5 mass% to 6 mass% (preferably 3. 5 wt% to 5. Cu 5 wt _^0/0), 0.3 wt% ~ 1. Mg of 5 wt% (preferably 0.5 mass% to 1. 3 mass _^0/0), 0.8 mass % to 4 wt% (preferably 1.8% to 3.5 mass _^0/0) a N i of, and N i (mass _^0/0) ≥ [chromatography 0. 68 XC u (mass _^0/0) + AA (mass _^0/0)] (where, AA is a constant, AA≥4. 2. preferably AA ≥4. 7.) an aluminum alloy that satisfies a relational expression made.

The molten alloy 25 5, 0.1 wt% to 1 wt% (preferably 0.2 mass% to 0. 5 wt _^0/0) Mn of 0.05 wt% to 0. 5 wt _^0/0 ( Preferably 0.1 quality The amount% to 0. 3 mass _^0/0) of C r, 0. 04 wt% to 0. Z r of 3 mass% (preferably 0.1 mass ⁰ /.～ 0.2 wt%), 0.0 1% to 0.1 5 weight _^0/0 (preferably 0.05 mass% to 0. 1 wt%) V of 0.0 1 wt% to 0. 2% by weight (the preferred properly 0.02 mass It is preferable to contain one or more of T i of ./. To 0.1 mass /.).

Further, it is preferable that Fe is contained in an amount of 0.15 mass% / _{0 to} 0.65 mass% (preferably 0.3 mass% to 0.5 mass%).

Moreover, P is 0.003 mass% to 0.02 mass. / ₀ (preferably 0.007 wt% to 0. 0 1 6 mass _^0/0) preferably includes.

 Further, 0.003 mass% to 0.03 mass% (preferably 0.01 mass% to 0.03 mass%).

02 mass ° / ₀ ) 3; ^ 0.1 mass% to 0.3 5 mass% (preferably 0.1 5 mass% / _{0 to} 0.25 mass%) Sb, 0.005 mass% to 0.0 1 5% by weight (preferably 0.00 1 wt% to 0. 0 1 wt%) Na of 0.00 1 wt% to 0. 0 2 mass _^0/0 (preferably 0.005 mass % to 0. 01 wt _^0/0) may contain one or more of the C a of, there are refining effect of the eutectic S i, preferred.

 The difference between the height of the liquid level 254 of the molten alloy stored in the tundish 250 and the height of the top surface of the inner wall surface 21 of the cylindrical saddle 20 1 is more preferably 5 Οιηπ! ~ 17 Omm. By providing a difference between the two, the pressure of the molten alloy 255 supplied to the cylindrical saddle mold 201 and the lubricating oil and the gas from which the lubricating oil has been vaporized are suitably balanced. This is because it is possible to easily produce a continuous alloy forged bar. By providing the tundish 250 with a level sensor for measuring and monitoring the height of the liquid level 254 of the molten alloy 255, this difference can be accurately controlled and maintained at a predetermined value.

As the liquid lubricant, vegetable oil which is a lubricating oil can be used. For example, rapeseed oil, castor oil, salad oil can be mentioned. These are less harmful to the environment Is preferable.

 The amount of the lubricating oil supplied is preferably 0.05 (mL / m i r!) To 5 (mL / m i n) [more preferably 0.1 (mL / m i n) to l (m L i n)]. If the supply amount is too small, the breakthrough of the lump will occur due to insufficient lubrication, and if it is excessive, the excess may be mixed in the lump and hinder the uniformity of the grain size distribution.

 The forging speed, which is the speed for pulling the solidified lumps 2 1 6 from the cylindrical mold 2 0 1, is 3 0 0 (mm / min) to 2 0 0 0 (mm / min) [more preferably 6 00 (m / min) to 20 00 (mm / min)]. This is preferable because the network structure of the crystallized product formed by forging becomes uniform and fine, resistance to deformation of the aluminum fabric at high temperatures increases, and high-temperature mechanical strength improves. Of course, the working effect of the present invention is not limited to the forging speed, but the effect becomes remarkable when the forging speed is increased.

 The amount of cooling water discharged from the cooling water shower device 20 5 is 5 (L / min) to 30 (LZmin) per mold (more preferably 25 (L / min) to 30 (L / min)). Preferably there is. If the amount of cooling water is too small, breakout may occur or the surface of the solidified lumps 2 16 may be remelted to form a non-uniform structure, hindering the uniformity of the crystal grain size distribution. On the other hand, if the amount of cooling water is excessive, the heat removal of the cylindrical saddle 201 will be so large that it becomes impossible to forge. Of course, the effect of the present invention is not limited to the amount of cooling water, but the effect becomes remarkable when the cooling ability is increased to increase the temperature gradient from the solidification interface into the cylindrical saddle 201.

The average temperature of the molten alloy 2 5 5 flowing from the tundish 2 5 0 into the cylindrical bowl 2 0 1 is the liquidus + 40 ° C to + 2 3 0 ° C (more preferably the liquidus + 6 0 ° C to 1020 ° C) is preferable. If the temperature of the molten alloy 2 55 is too low, a coarse crystallized product may be formed before and after the cylindrical saddle mold 20 1, which may hinder the uniformity of the crystal grain size distribution. On the other hand, if the temperature of the molten alloy 2 5 5 is too high, a large amount of hydrogen gas will be contained in the molten alloy 2 5 5. This is because the slag is taken in as a single porosity in the solidified lumps 2 1 6 and may hinder the uniformity of the crystal grain size distribution.

 In the present invention, these forging conditions are such that the eutectic Si or intermetallic compound of the structure of the forged product is hardly agglomerated and spheroidized, and the network structure of the crystallized product formed during continuous forging or the needle-like crystallized product or Since it is controlled so as to be an aggregate of crystallized substances, the effect of each subsequent heat treatment is effectively exhibited, which is preferable.

 In the present invention, the forged rod after forging is used as a pre-heat treatment at a temperature of 110 ° C. to 48 ° C. (preferably 110 ° C. to 37 ° C. It is important to hold for 2 to 6 hours. The temperature condition is more preferably room temperature, but the effect can be obtained even if the temperature is less than that.

 When the pre-heat treatment is performed as described above, a network structure of crystallized substances or acicular crystallized substances or aggregates of crystallized substances formed during continuous forging in a structure is formed and an aluminum molded article partially remaining after heat treatment. Thus, the crystallized material of these shapes acts as a resistance to deformation of the aluminum fabric at high temperatures, and as a result, excellent mechanical strength is obtained even at high temperatures of 250 ° C to 400 ° C. can get. That is, since the network structure of the crystallized material or the acicular crystallized material or the aggregate of crystallized materials becomes resistant to deformation at a high temperature at which the aluminum fabric is softened, the aluminum molded product is excellent in high-temperature mechanical strength. On the other hand, if the pre-heat treatment temperature is high and the forming ratio is high, the network structure of crystallized matter or acicular crystallized product or aggregate of crystallized product is divided and aggregated into particles, and the crystallized product is softened at high temperature. It will be in the state disperse | distributed uniformly in the finished aluminum cloth. For this reason, the resistance of the crystallized material to the deformation of the aluminum dough at high temperatures is reduced, and the high temperature mechanical strength cannot be increased.

The present invention has the alloy composition described above, and the aluminum base material softens and becomes very deformable. Crystallization that resists deformation of the aluminum base material at a further high temperature range of 250 ° C. to 400 ° C. Partially leave a network structure, needle-like structure or aggregate of things This increases the high-temperature mechanical strength.

 If the homogenization treatment is suppressed or omitted, such as a low-concentration alloy with a relatively low crystallized content, such as a network of crystallized products and a relatively small amount of crystallized material, it is difficult to recrystallize. This is a high Si-based alloy that has many crystallized materials as in the present invention and has a network and a needle-like structure that can be seen during fabrication, and maintains the network and needle-like structure as much as possible. Therefore, it is different from those for improving the temperature.

 As described in the background section above, what is disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2 0 0 2-2 9 4 3 8 3) relates to a 6 0 0 0 series alloy. The reason for suppressing or omitting the temperature of the homogenization treatment is not to obtain high temperature characteristics, but to suppress recrystallization and improve mechanical properties at room temperature. Originally, the alloy system is different, and it is a low-concentration alloy with relatively few crystallized substances, and the network structure and needle-like structure of the crystallized substances are hardly seen. By controlling the homogenization process at a low temperature, it suppresses recrystallization. A 1 — M n system, 1–O is used to precipitate system compounds finely. It is a high Si system alloy with many crystallized materials as in the present invention, and a network structure and needle-like structure can be seen at the time of fabrication, and it is intended to improve the high temperature by maintaining the network structure and needle-like structure. Is different.

 In particular, when increasing the high-temperature mechanical strength of the material and improving the forgeability, it is preferable that the holding temperature of the preheating treatment is 20 ° C. to 3700 ° C. Within this temperature range, eutectic Si and intermetallic compounds during the pre-heat treatment are less likely to agglomerate and spheroidize, and a network structure of crystallized substances or acicular crystallized substances or aggregates of crystallized substances formed during continuous fabrication. The body remains partially after forging and post-heat treatment, resulting in an aluminum molded product with excellent high-temperature mechanical strength.

In particular, when the high-temperature mechanical strength of the material is further increased, the holding temperature of the pre-heat treatment is preferably 10 ° C. to 200 ° C. Within this temperature range, eutectic Si and intermetallic compounds during pre-heat treatment hardly form agglomerated spheroids and are formed during continuous fabrication. The network structure of the crystallized product or the acicular crystallized product or the aggregate of the crystallized product partially remains even after forging and post-heat treatment, resulting in an aluminum molded product having excellent high-temperature mechanical strength.

 Furthermore, in order to further improve the forging formability of the material, it is preferable that the holding temperature of the pre-heat treatment is 370 ° C. to 48 ° C. Within this temperature range, the eutectic Si and the intermetallic compound during the pre-heat treatment are agglomerated to some extent and the deformation resistance during forging is reduced, so that an aluminum molded product with excellent forging formability is obtained. In this temperature range, the network structure of crystallized matter or acicular crystallized product or aggregate of crystallized product formed during continuous forging partially remains after forging and post-heat treatment. Aluminum molded products with excellent mechanical properties can be obtained.

 The pre-heat treatment process may be provided between the forging process after forging. For example, after forging

It can be processed within one day or put into the forging process within one week after processing. In the meantime, correction and peeling can be performed.

 Next, an example of the forging process included in the present invention will be described. 1) a process of cutting a continuous forged round bar to a predetermined length; 2) a process of preheating the cut material; 3) a process of lubricating the installed material; 4) The manufacturing method includes a step of forging into a mold and forging and 5) a step of discharging a forged product from the mold by a knockout mechanism.

 Lubricant can be applied to the forging material and heated before the upsetting process. The upsetting process can be omitted.

 Lubricant treatment may be water-soluble lubricant application or ponde treatment. For example, it is preferable that after the material is subjected to a bondage treatment, it is heated to 3880 ° C. to 480 ° C. as a preheating and then put into a forging device. When preheated to 3800 ° C to 4800 ° C, the deformation of the material is improved and it becomes easy to form a complex shape.

A water-based lubricant is preferred as the lubricant, and a water-soluble graphite lubricant is more preferred. Good. This is because graphite is well baked on the material. In this case, for example, after applying a lubricant to a material at 70 ° C. to 35 ° C., after cooling the material to room temperature (for example, holding for 2 hours to 4 hours), It is preferable to heat to 480C to 480 ° C and put into a forging device. A water-based lubricant is preferable as the lubricant, and a water-soluble graphite lubricant is more preferably used. This is because black ^^ sticks well to the material.

 Apply lubricant to the mold surface before loading the material. The amount of lubricant can be adjusted to a more appropriate state according to the combination of the upper mold and the die by adjusting the spraying time. It is preferable to use an oil-based lubricant as the lubricant. For example, mineral oil can be used. This is because water-based lubricants can lower the mold temperature, but this can be suppressed. It is more preferable that the oil-based lubricant is a mixture of graphite and mineral oil because the lubricating effect is enhanced.

 The heating temperature of the mold is preferably 1550 ° C to 2500 ° C. This is because sufficient plastic flow can be obtained.

 In the present invention, it is preferable that the processing rate of the portion requiring high temperature fatigue strength in forging is 90% or less (preferably 70% or less). Below this processing rate, the network structure of crystallized matter or acicular crystallized product or aggregate of crystallized product is suppressed, and a molded product having excellent high-temperature mechanical strength is obtained.

 In the molded product, it is sufficient that the portion requiring high-temperature mechanical strength satisfies this processing rate.

 If plastic working such as an upsetting process is performed before forging, it is preferable to consider the processing rate as the total of these. For example, in the case of a molded product having a complicated shape, the processing rate per processing is 10. /. It is preferable to set it to multiple times (preferably twice) at ˜80% (more preferably from 10% to 50%). For example, the first time is preferably 10% to 50% (more preferably 10% to 30%).

Here, the processing rate is defined as follows. Machining rate = (Thickness before plastic working-Thickness after plastic working) / (Thickness before plastic working) X 1 00%

 Post-heat treatment is applied to the forged product. As the post heat treatment, a solution treatment and an aging treatment can be used in combination. Post heat treatment can be done within one week after processing.

 Specifically, the forged product can be subjected to a solution treatment, for example, under the condition of holding at 480 ° C to 520 ° C (preferably 490 ° C to 510 ° C) for 3 hours.

 As post-heat treatment other than the above, forged products can be subjected to J IS standard T5 heat treatment or T6 heat treatment.

 In the present invention, the forged product taken out is not subjected to solution solution and quenching, but is maintained at 1 70 ° C to 230 ° C (preferably 190 ° C to 220 ° C) for 1 hour to 10 hours as an aging treatment. It is preferable. This is preferable because the crystallized product network, the acicular crystallized product, or the aggregate of crystallized product can be prevented from being divided and agglomerated, and the molded product has excellent high-temperature mechanical strength.

 The alloy structure of the molded product produced by such a method is difficult to progress in the aggregation and spheroidization of eutectic Si and intermetallic compounds, and the crystal structure or ^ " A crystallized product or an aggregate of crystallized products partially remains even after forging and post-heat treatment, resulting in an aluminum molded product having excellent high-temperature mechanical strength.

Moreover, the alloy composition is, S i of 1 0.5 wt% to 1 3.5% by weight (preferably 1 1.5 mass% to 1 3 mass _^0/0), 2.5 wt% to 6 wt% (Preferably 3.5 wt% to 5.5 wt%) Cu, 0.3 wt% to 1.5 wt% (preferably 0.5 wt% to 1.3 wt%) Mg, 0.8 wt% to 4 wt _^0/0 (preferably 1.8 mass ⁰ /.～ 3.5 wt%) a N i of, and N i (mass. / ₀₎ ≥ [chromatography 0.68 11 (wt% ) + AA (mass%)] (Also, AA is a constant, and is an aluminum alloy satisfying the relational expression AA 4.2. AA ≥ 4.7 7). The alloy composition is 0.1 mass% to 1 mass% (preferably 0.2 mass% to 0.5 mass%) of Mn, 0.05 mass% to 0.5 mass% (preferably 0.1 mass%). % ~0. C r of 3 wt%), 0.04 wt ° / ₀ ~0. Z r of 3 mass% (preferably 0.1% to 0.2 mass _^0/0), 0.0 1 mass% to 0. 1 5 mass _^0/0 (preferably 0.0 5 wt% to 0. 1 wt%) V of 0.01 mass% to 0. 2% by weight (preferably 0.02% to It is preferable to contain one or more of 0.1 mass% Ti.

Furthermore, Fe 0.15 mass. / _{0 to} 0.6 5% by mass (preferably 0.3% to 0.5% by mass) / ₀ is preferable.

Further, P is set to 0.003 mass ° / _{0 to} 0.02 mass% (preferably 0.007 mass ° / _0.

~ 0.016% by mass).

Further, 0.003 wt% to 0. 03 wt% (preferably 0.01 mass% to 0. 02 wt _^0/0) S r of 0.1% to 0.35 mass _^0/0 (preferably 0.1 5 wt% to 0. S b of 25 wt%), 0.0005 wt% to 0. 01 5 wt% (preferably 0.001 wt% to 0. 0 1 weight ⁰ /.) of Na, 0.00 1 wt% to 0. 02 mass _^0/0 (preferably 0.005 wt% to 0. 01 wt%) may contain one or more of the C a of the eutectic There is an effect of miniaturizing Si, which is preferable.

(Example)

 EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.

 (Examples 1 to 16)

 [Production conditions]

No .: Using the production system shown in LI1, aluminum alloy molded articles of Examples 1 to 16 shown in Table 1 and Comparative Examples 1 to 10 shown in Table 2 were produced. Aluminum alloy composition (mass%) Fatigue strength stress Homogenization (Unit: MPa) Fine heat treatment after upsetting

 Processing temperature AA value

 Machining rate (Ding 6

 (° C), T5)

 Si Fe Cu Mn Mg i Ti P Sr Temperature conditions Temperature conditions

 300 ° C 350 ° C

Example 1 370 50% Ding 6 10.5 0.25 2.7 One 0.95 3.8 ― ― 0.015 60 45 5.64 Example 2 370 50% Ding 6 10.5 0.25 2.7 ― 0.95 3.8 ― 0.015 ― 59 44 5.64 Example 3 370 50% T6 12.8 0.48 3.0 0.23 0.95 3.0 0.075 0.018 ― 59 43 5.04 Example 4 370 50% T5 12.8 0.48 3.0 0.23 0.95 3.0 0.075 0.018 One 62 44 5.04 Example 5 370 50% T6 11.8 0.33 3.2 ― 0.72 2.2 ― 0.005 ― 54 39 4.38 Example 6 370 50% T6 12.8 0.25 3.8 ― 0.95 1.8 ― 0.018 ― 53 38 4.38 Example 7 370 50% T6 13.4 0.25 4.1 ― 1.10 2.2 ― 0.018 ― 57 43 4.99 Example 8 370 50% Ding 6 13.4 0.61 4.1 0.32 1.21 2.2 One 0.010 ― 58 43 4.99 Example 9 200 or less 50% T6 13.4 0.61 4.1 0.32 1.21 2.2 ― 0.010 One 59 44 4.99 Example 1 0 370 50% T6 12.8 0.48 4.5 0.23 0.95 1.5 0.075 0.018 ― 55 40 4.56 Example '' 370 50 % Ding 6 12.5 0.28 5.1 0.21 1.14 1.1 ― 0.007 One 55 39 4.57 Example 1 2 370 50% T6 12.8 0.25 5.5 ― 0.95 1.0 One 0.018 ― 57 43 4.74 Example 1 3 370 50% Ding 6 12.8 0.48 5.5 0.23 0.95 1.0 0.075 0.018 ― 58 44 4.74 Example 1 4 370 50% T6 10.5 0.25 5.7 One 0.95 3.5 ― 0.010 One 62 47 7.38 Example 1 5 370 88% T6 12.8 0.48 3.0 0.23 0.95 3.0 0.075 0.018 One 58 41 5.04 Example 1 6 470 50 % T6 12.8 0.48 3.0 0.23 0.95 3.0 0.075 0.018 One 58 41 5.04

¾2 As the continuous forging device 8 1 constituting the production system, the hot top continuous forging machine shown in FIG. 5 was used, and the comparisons shown in Examples 1 to 16 and Table 2 having the compositions shown in Table 1 were made. Examples 1 to 10 Aluminum alloy round bars of 85 mm (mm) were fabricated respectively. The above hot top continuous forging machine is a forging machine using the gas pressure hot top forging method, in which gas and lubricating oil are introduced into the clearance between the header and the mold, and the molten alloy supplied into the mold is made of The pressure and the lubricating oil and the gas from which the lubricating oil is vaporized are suitably balanced. With this configuration, the area where the molten aluminum comes into contact with the mold becomes narrow, so that the molten alloy can be rapidly cooled and solidified with cooling water, and an aluminum alloy continuous forged rod can be stably produced. '

 Next, as a pre-heat treatment step, each continuous forged round bar was homogenized at the temperatures shown in Tables 1 and 2. Each continuous forged round bar was cut to a thickness of 20 mm or 8 O mm to obtain a forging material. Next, the forging material was preheated to 4220 ° C., and then an upsetting process was performed at predetermined upsetting rates shown in Tables 1 and 2 to perform plastic processing into a predetermined shape.

 In Examples 5 to 7 and 10 to 13, the crack generation rate was evaluated when the upsetting rate was set to 55%. The evaluation results are shown in Table 3. In Table 3, the 〇 and 厶 marks indicate that the cracking rate during the installation process was less than 1% and 1% or more, respectively.

 (Table 3) Homogenization Upset Content in aluminum alloy (wt%) Cracking

 AA value

Processing temperature (° c) Processing rate Cu Ni generation rate Example 5 370 55% 3.2 2.2 4.38 厶 Example 6 370 55% 3.8 1.8 4.38 〇 Example 7 370 55% 4.1 2.2 4.99 厶 Example 1 0 370 55% 4.5 1.5 4.56 Yes Example 1 1 370 55% 5.1 1.1 4.57 Yes Example 1 2 370 55% 5.5 1.0 4.74 Yes Example 1 3 370 55% 5.5 1.0 4.74 Yes Thereafter, predetermined post-heat treatment steps shown in Table 1 and Table 2 were performed on the plastically processed material, and the above Examples and Comparative Examples were respectively produced.

 In the post-heat treatment step, the plastic-processed product is water-quenched and held for 2 hours at 10 ° C. T5 heat treatment, or the plastic-processed product is held at 500 ° C for 2.5 hours and then water-baked. The heat treatment was performed by either T 6 heat treatment, which was put in and held at 210 ° C for 6 hours.

 [Fatigue strength evaluation]

 For each of the above examples and comparative examples, the fatigue strength was evaluated by the following method. Test pieces from each of the examples and comparative examples were manufactured by machining and pre-heated at 30.0 ° C or 350 ° C for 100 hours using an Ono-type rotary bending fatigue tester, then 300 ° C The fatigue strength of the specimen was evaluated in each environment at 350 ° C and 350 ° C. Stress that was not damaged was measured by applying 10 million cycles of stress.

 Composition, heat treatment conditions, upsetting rate, fatigue strength evaluation result and Ni (mass%) = [0.68 XC u (mass%) + AA (mass./.) In each example and comparative example. Tables 1 and 2 show the constants AA that satisfy the relational expression defined by Fig. 6 shows the relationship between the Ni and Cu contents in the compositions of the examples and comparative examples. In FIG. 6, the AA values of Examples 1 to 14 are represented by the symbols S 1 to S 14 respectively, and the eight values of Comparative Examples 1 to 10 (excluding Comparative Example 6) are respectively 1 It is represented by the sign of ~ 10.

 Examples 1 to 16 were all produced by the production method of the present invention and, as can be seen from Table 1, have a fatigue strength of 33 MPa or more at 350 ° C. Thus, since Examples 1 to 16 manufactured by the manufacturing method of the present invention all have a target fatigue strength, they are preferably used for parts that require mechanical strength at high temperatures. be able to.

The aluminum alloy used in the production method of the present invention must have a composition in which the Ni and Cu contents are included in the region surrounded by A—B—C and D—E—A in FIG. Let's say.

 Examples 6 and 10 in which the contents of Ni and Cu are included in the region surrounded by D—E—H—I and D are all 5 5% as shown in Table 3. It can be processed well at an ultra-upsetting rate. Thus, in the present invention, it is more preferable to use an aluminum alloy containing Cu such that the Ni content is 2.0 wt% or less and AA≥4.2. .

 In contrast, Comparative Examples 1 to 5 and 7 to 10 having compositions outside the range of the alloy composition defined in the manufacturing method of the present invention are all targeted fatigue strengths as shown in Table 2. Did not have. Comparative Examples 8 and 10 were further inferior in plastic workability, and cracks occurred during upsetting. The “* 1” displayed in Table 2 indicates that the comparative test specimen could not be collected. In addition, the A A value of Comparative Examples 1 to 4 was less than 4.2. Further, Comparative Example 6 in which the pre-heat treatment step was performed at a temperature outside the temperature range defined in the production method of the present invention did not have the target fatigue strength.

 [Evaluation of metal structure]

 Each example and each comparison were made by cutting out the structure observation sample from the center of the longitudinal section of each Example in Table 1 and each Comparative Example in Table 2, micropolishing, and observing the network structure of the crystallized product from the microphotograph. Example metallographic structures were evaluated.

 In the structures of the examples, it was confirmed that the network texture of crystallized substances or acicular crystallized substances or aggregates of crystallized substances formed during continuous fabrication remained partially after molding and heat treatment. did it.

In the examples, the area occupancy of the eutectic S i is 8% or more, the average grain size of the eutectic S i is 5 μm or less, and the eutectic S i needle ratio is 2.4 or more. % Of the intermetallic compound is 1.2% or more, the average particle size of the intermetallic compound is 1.5 μm or more, the length of the intermetallic compound or the aggregate of the intermetallic compounds in contact Those with a length of 3 μm or more were 30% or more. In particular, in Examples 10 and 13 containing Ni and Cu at the above-mentioned preferable concentrations, as shown in Table 4, the average particle diameter of the eutectic Si is 2.5 μπι or less. It can be seen that about 80% of the eutectic Si needle-like ratio is 1.4 or more, and about 90% of the intermetallic compound aggregate length is 3 μηι or more.

 In addition, according to the results in Table 1 and Table 4, the constant ΑΑ is larger than 4.7 Example 1

3 has a larger amount of network-like or acicular intermetallic compounds that contribute to high-temperature strength compared to Example 10 where the constant 未 満 is less than 4.7, and the fatigue strength is higher than Example 10. I understand that. Thus, in the present invention, an aluminum alloy molded article prepared so that the constant ΑΑ is 4.7 or more is preferable.

 On the other hand, in each of the above comparative examples, the content of the eutectic Si needle-like ratio of 1 or 4 or more, the length of the intermetallic compound, or the length of the aggregate of the intermetallic compound in contact with each other is described in the examples It was small compared. For example, as shown in Table 4, Comparative Example 6 has only about 22% of eutectic Si needle-like ratios of 1 and 4 or more, and the length of the intermetallic compound or the intermetallic compound in contact with it. Only about 28% of the aggregates were 3 xm or longer.

 (Table 4) Eutectic Si intermetallic compound

 Soil occupation table Needle ratio E Product occupation ratio Needle ratio Average particle diameter Average particle diameter

(%) 1.4 or more (%) 1.4 or more Example 10 8.6% 2.4 m 78% 7.4% 2.6 m 88% Example 13 8.5% 2.5 jWm 80% 7.8% 2.7 jU 89% Comparative Example 6 8.5% 2.0 m 22% 7.2 % 1.9 im 28%

(Examples 1 7, 1 8)

 [Production conditions]

 Examples 17 and 18 and Comparative Examples 1 1 and 12 were respectively produced in the same manner as in Examples 1 to 16 and Comparative Examples 1 to 10 with the compositions and production conditions shown in Table 5. Manufactured. Comparative Examples 1 and 3 were formed from powdered extruded forged material, except that they were not formed from an aluminum alloy continuous forged round bar and were not homogenized. It was manufactured by the same manufacturing method. Examples 1 7 and 1 8 and Comparative Examples 1 1 to 1 3 are all screws having a crown surface of 1 ° having a diameter of 8 O mm and a thickness of 8 mm as shown in FIGS. 7 (a) to (c). It was formed as an aluminum alloy molded product having the shape of Ton 1.

 [Fatigue strength evaluation]

 For Examples 17 and 18 and Comparative Examples 1 1 to 13, fatigue strength was evaluated by the following method.

 First, after preheating for 300 hours at 30 ° C. or 35 ° C. to the biston 1 of each example and each comparative example, the crown 1 of each example and each comparative example 1 A test piece 1 1 was cut out from the center of 0. Under each temperature environment corresponding to the preheating temperature, the fatigue strength of each test piece 11 was evaluated by a single swing tensile fatigue test. In the above fatigue test, the stress ratio was R = −0.1, and the unscored maximum stress was defined as the fatigue strength after 100 thousand times. Table 5 shows the fatigue strength evaluation results of Examples 17 and 18 and Comparative Examples 11 to 13.

As can be seen from Table 5, in Examples 17 and 18, fatigue strength at 3500 ° C is preferred for parts that require mechanical strength at high temperatures. Furthermore, the fatigue strength at 300 ° C exceeds 55 MPa. In addition, Examples 17 and 18 correspond to Examples 10 and 13 in which the same manufacturing conditions are used except for the shape. Stable mechanical strength at high temperatures is used regardless of the evaluation method. Have Homogenization Aluminum alloy composition (mass. / ₀ ) Fatigue strength stress

 Post heat treatment (Unit: MPa) Material Processing temperature AA

 (T6, T5) value

(° C) Si Fe Cu n Mg Ni Ti P / dish 'Article Temperature conditions

300 cases. C 350 ° C Comparative Example 1 1 Continuous Forging Bar 370 T6 12.3 0.3 3.3 0.15 0.85 1.8 0.05 0.005 64 45 4.04 Comparative Example 1 2 Continuous Forging Bar 370 T6 12.4 0.3 1.0 ― 1.04 1.0 ― 0.010 45 33 1.66 Comparative Example 1 3 Extruded powder ― T6 1 1.7 5.3 2.5 ― 1.1 ― ― ― 80 59 1J0 Example 1 7 ¾ 錶 Bar 370 T6 12.8 0.48 4.5 0.23 0.95 1.5 0.075 0.018 70 52 4.56 Example 1 8 Continuous forged rod 370 T6 12.8 0.48 5.5 0.23 0.95 1.0 0.075 0.018 73 54 4J4

On the other hand, Comparative Example 11 corresponds to Comparative Example 2 in which the AA value is less than 4.2 and the same manufacturing conditions except for the shape are used. From the fatigue strength evaluation results of Comparative Example 2 in Table 2 and Comparative Example 11 in Table 5, Comparative Example 11 is considered to lack the reliability of mechanical strength at high temperatures.

 Comparative Example 1 2 has AA = 1.6 8 and the fatigue strength at 3500 ° C is 4 3 M

Significantly lower than Pa.

 In addition, although Comparative Example 13 formed from the powdered extruded forged material has higher fatigue strength than Examples 17 and 18 although AA = 1.7, it was formed by compaction. There is a disadvantage that the fine part, for example, the skirt part 12 tends to become brittle. In this way, the molded product using the powder extruded material is compared with the aluminum alloy molded product having a forging process using a continuous forged rod made of an aluminum alloy as a material. Ductility and toughness are inferior.

 The aluminum alloy molded article produced by the production method of the present invention is excellent in ductility, toughness and fatigue strength, and can be suitably used for a crown surface portion of an internal combustion engine biston. Industrial applicability

As described above, the present invention is a method for manufacturing an aluminum alloy molded article having a forging process using a continuous forged rod made of an aluminum alloy as a raw material, wherein the aluminum alloy is Si, Cu, Since it contains Mg and Ni, according to the present invention, it is possible to obtain a molded article having high-temperature fatigue strength and good forgeability, ductility, and toughness. Also, and the N i and C u, N i (mass _^0/0) ≥ [one 0. 6 8 XC u (mass _^0/0) + 4.2 (wt%)] Since satisfying the relational expression, The fatigue strength characteristics at higher temperatures can be improved.

By using the aluminum alloy molded product of the present invention, a conventional internal combustion engine screw 7 065331

 39

It is possible to reduce the thickness of the internal combustion engine piston. And, it can answer the weight reduction demanded by the market, and can realize reduction in fuel consumption and improvement in output of the internal combustion engine.

Claims

The scope of the claims  1. In a method for producing an aluminum alloy molded article having a forging process using a continuous forged rod made of an aluminum alloy as a material, Aluminum alloy is 10.5 mass% to 13.5 mass% Si, 2.5 mass% to 6 mass% Cu, 0.3 mass% to 1.5 mass ⁰ /. And Mg containing 0.8 mass% to 4 mass% Ni, and Ni (mass%) ≥ [One 0.668 XCu (mass%) +4.2 (mass%)] Satisfied,  Heat treatment consisting of pre-heat treatment process for material, pre-heating process for forging process for material, and post-heat treatment process for aluminum alloy molded product  The pre-heat treatment step includes a treatment of holding at 10 to 480 ° C for 2 to 6 hours. A method for producing an aluminum alloy molded product,  2. The method for producing an aluminum alloy molded article according to claim 1, wherein a heat treatment temperature in the pre-heat treatment step is 200 ° C to 370 ° C. 3. The method for producing an aluminum alloy molded article according to claim 1, wherein a heat treatment temperature in the pre-heat treatment step is 1 to 200 ° C.  4. The method for producing an aluminum alloy molded article according to claim 1, wherein the heat treatment temperature in the pre-heat treatment step is 370 ° C to 480 ° C.  5. The aluminum alloy molding according to any one of claims 1 to 4, wherein the post heat treatment step is maintained at 170 ° C to 230 ° C for 1 hour to 10 hours without performing a solution treatment. Product manufacturing method. 6. Aluminum alloy is 0.1 5 mass ⁰ /. The method for producing an aluminum alloy molded article according to any one of claims 1 to 5, comprising ~ 0.65 5 mass% of Fe. 7. The aluminum alloy contains 0.003 mass% to 0.02 mass ° / ₀ P, The method for producing an aluminum alloy molded article according to any one of claims 1 to 6.  8. Aluminum alloy is from 0.003 mass% to 0.03 mass% 31: 0.1 mass. /. ~ 0.35 mass ° /. 313, 0.0005 wt% to 0.015 wt% Na, 0.001 wt / °. ~ 0.02 mass. /. The method for producing an aluminum alloy molded article according to any one of claims 1 to 7, comprising any one kind or a combination of two or more kinds of Ca. 9. Aluminum alloy has 0.1 mass. /. ~ 1. 0% by weight] \ 11, 0.05 mass _^0/0 to 0.5 mass ⁰ /. Cr, 0.04 mass% to 0.3 mass ⁰ /. Zr, 0.01 mass ⁰ /. ~ 0.1 5 mass ⁰ /. V, 0.01 mass ⁰ /. The method for producing an aluminum alloy molded article according to any one of claims 1 to 8, comprising any one kind or a combination of two or more kinds of Ti of 0.2 mass%.  10. The method for producing an aluminum alloy molded article according to any one of claims 1 to 9, wherein a processing rate of a portion requiring high temperature fatigue resistance in a forging process is 90% or less. .  1 1. The method for producing an aluminum alloy molded article according to any one of claims 1 to 10, wherein a preheating temperature before processing is 380 ° C to 480 ° C in the forging process.  12. The continuous forging rod is made of an aluminum alloy with an average molten metal temperature of liquidus + 40 ° C to + 230 ° C, with a forging speed of 80 (mmZmin) to 2000 (mm / min). The method for producing an aluminum alloy molded article according to any one of claims 1 to 11, which is obtained by forging by a continuous forging method.  13. An aluminum alloy molded article manufactured by the manufacturing method according to any one of claims 1 to 12, Net woven structure or needle shape of crystallized material formed during continuous fabrication in the structure An aluminum alloy molded product characterized in that a crystallized product or an aggregate of crystallized products partially remains after forming and heat treatment.  14. An aluminum alloy molded article manufactured by the manufacturing method according to any one of claims 1 to 12, Eutectic S i has an area occupancy of 8% or more, Eutectic S i has an average particle size of 5 zin or less, Eutectic S i needle ratio 1. The ratio is 1.2% or more, the average particle size of the intermetallic compound is 1 or more, the length of the intermetallic compound or the length of the aggregate of the intermetallic compound in contact is 3 _βm or more, and 30% or more. Is,  An aluminum alloy molded product characterized by that.  1 5. An aluminum alloy engine piston with a crown surface and a skirt.  The high-temperature fatigue strength of the crown surface portion is 5 OMPa or more,  The aluminum alloy formed TOo according to claim 1 3 or 14  16. A series of processes from a molten metal to an aluminum alloy molded product is constructed as a continuous line, and at least in that process, the manufacture of an aluminum alloy molded product according to any one of claims 1 to 12 A production system characterized by including processes by methods.