WO2011096212A1

WO2011096212A1 - Forged billet, process for production of forged billet, and process for production of wheel

Info

Publication number: WO2011096212A1
Application number: PCT/JP2011/000592
Authority: WO
Inventors: 小野光太郎; 餅川昭二
Original assignee: ワシ興産株式会社
Priority date: 2010-02-02
Filing date: 2011-02-02
Publication date: 2011-08-11
Also published as: JP2013078770A

Abstract

Disclosed are: a forged billet having excellent mechanical strength; a process for producing a forged billet; a pre-wheel having a light weight and excellent mechanical strength; and a process for producing a wheel. Specifically disclosed is a forged billet (10) produced by casting a light metal alloy to produce a casted billet (4) and compressing the casted billet (4) by applying pressure to finely divide the metal structure of the casted billet (4), wherein the light metal alloy is duralumin.

Description

Forged billet, method for producing forged billet and method for producing wheel

The present invention relates to a forged billet, a method for producing a forged billet, a finished product or a semi-finished product using the forged billet, and a method for producing a wheel using the forged billet.

In general, automobile tires are provided with a metallic wheel as a support.
In recent years, such a wheel has been desired to be as light as possible and to have a high design, and the diameter of the wheel tends to increase particularly in passenger cars. This is to reduce vibration during driving and to improve steering performance.

As such a wheel, for example, a method of manufacturing a wheel by forging a billet obtained by cutting an aluminum alloy round bar manufactured by casting with a die (see, for example, Patent Document 1) ), Or a vehicle wheel (for example, see Patent Document 2) made of a magnesium alloy obtained by strain-processing and recrystallizing a cast magnesium alloy, and a vehicle in which a protruding portion is formed in the rim diameter center direction on the inner diameter portion of the wheel rim flange. A wheel for use (see, for example, Patent Document 3) is known.
Moreover, what was formed by forging an aluminum alloy is known as a wheel for aircrafts (for example, refer nonpatent literature 1).

These wheels are all obtained by forging from a cast billet (hereinafter referred to as “cast billet”).

Japanese Patent Laid-Open No. 2007-2110017 JP 2007-308780 A JP 2008-137562 A

However, all of the wheels described in Patent Documents 1 to 3 and Non-Patent Document 1 are stretched only partially rather than entirely because the cast billet is formed into a complicated shape by forging. As a result, in terms of the metal structure, a portion having a weak impact and toughness (hereinafter referred to as “mechanical strength”) is unevenly distributed. That is, it cannot be said that the obtained wheel is sufficiently excellent in mechanical strength.

For example, the conventional wheel has a drawback that the weight of the wheel itself is increased because it is necessary to increase the thickness of the wheel in order to ensure sufficient mechanical strength.

The present invention has been made in view of the above circumstances, and has a forged billet excellent in mechanical strength that can be used in various applications, a manufacturing method of the forged billet, and a lightweight and mechanical strength by using the forged billet. It aims at providing the manufacturing method of the finished product or semi-finished product, and wheel which is excellent in thickness.

The present inventors diligently studied to solve the above-mentioned problems. As a result, duralumin was used as a light metal alloy, and the cast billet was temporarily pressed to a predetermined size, rather than forging the cast billet. The inventors have found that the above problems can be solved by compressing and setting the Charpy impact value measured according to JIS-Z2242 to 30 J / cm ² or more, and have completed the present invention.

That is, the present invention is (1) a forged billet obtained by casting a light metal alloy to form a cast billet, and compressing and compressing the cast billet to refine the metal structure of the cast billet, wherein the light metal alloy is duralumin. Forged billets.

The present invention resides in (2) the forged billet according to the above (1), wherein 50 to 80% of the total volume of grain boundary precipitates is refined by pressure compression and stress corrosion cracking is suppressed.

The present invention resides in (3) the forged billet according to the above (1) or (2), wherein the tensile strength measured according to JIS-Z2241 is 400 MPa or more.

The present invention resides in (4) the forged billet according to any one of the above (1) to (3), wherein the 0.2% proof stress measured according to JIS-Z2241 is 300 MPa or more.

In the present invention, (5) the elongation measured according to JIS-Z2241 is 20% or more, and the Charpy impact value measured according to JIS-Z2242 is 30 J / cm ² or more. It exists in the forge billet as described in any one of these.

The present invention resides in (6) a method for producing a forged billet according to any one of the above (1) to (5), which satisfies the following formula.
H1 / H2 ≧ 4.0
(In the formula, H1 indicates the length in the direction in which the cast billet is compressed and compressed, and H2 indicates the length in the direction in which the forged billet is compressed and compressed.)

The present invention resides in (7) the method for producing a forged billet according to the above (6), wherein the pressure compression is performed by closed forging, swing forging, hammer forging, section forging or free forging.

The present invention (8) is obtained by compressing and compressing a cast billet in one direction to obtain a pre-forged billet, and further compressing and compressing the pre-forged billet in a direction different from the direction in which the pre-forged billet is compressed and compressed. Or it exists in the manufacturing method of the forge billet as described in (7).

In the present invention, (9) a cast billet is pressure-compressed in one direction to form a pre-forged billet, and the pre-forged billet is further pressure-compressed in a direction different from the pressure-compressed direction to deform the outer portion. The method for producing a forged billet according to the above (6) or (7), which is obtained by further pressing and compressing.

The present invention is (10) press-compressing a cast billet in one direction to form a pre-forged billet, further compressing and compressing the pre-forged billet in a direction different from the direction in which the pre-forged billet is compressed, The method for producing a forged billet according to the above (6) or (7), wherein the outer portion is compressed under pressure.

According to the present invention, (11) the step of compressing and compressing the cast billet in one direction and the step of compressing and compressing the cast billet in a direction different from the direction of pressurizing and compressing are performed in the same step using swing forging. 8) It exists in the manufacturing method of the forge billet of description.

The present invention is (12) the above-mentioned (6) to (11), which is used for flying parts, transportation equipment parts, industrial equipment parts, building materials, optical equipment parts, or members for these uses. The method for producing a forged billet according to any one of the above.

The present invention resides in (13) a finished product or a semi-finished product obtained by molding the forged billet according to any one of (1) to (5) above.
Here, the semi-finished product means a product in the previous stage of machining in a process of forging a forged billet and machining to a finished product. Moreover, when a semi-finished product distributes, it may be called an intermediate product.

The present invention resides in (14) a finished product or a semi-finished product obtained by molding a forged billet obtained by the method for producing a forged billet according to any one of (6) to (12) above.

The present invention is (15) a method for manufacturing a wheel using a forged billet obtained by the method for manufacturing a forged billet according to any one of (6) to (11) above, comprising a hub portion, a spoke portion, The disk part, the outer flange part, the inner rim part, and the inner flange part are made of a wheel having a Charpy impact value of 30 J / cm ² or more.

In the present invention, when the (16) wheel and the A6000 series wheel made of an A6000 series aluminum alloy have the same mechanical strength, the wheel is at least 10% lighter than the A6000 series wheel made of an A6000 series aluminum alloy. The wheel manufacturing method according to the above (15).

In the present invention, (17) the average thickness of the well portion and the inner rim portion is 1.8 to 2.5 mm, the average thickness of the hub portion is 35 to 66 mm, and the wheel and the A6000 series aluminum alloy are used. In the case where the A6000 series wheel has the same mechanical strength, the wheel is at least 15% lighter than the A6000 series wheel made of an A6000 series aluminum alloy.

According to the present invention, (18) a pre-disc portion, a pre-outer rim portion and a pre-inner rim portion are formed by extrusion forging on a forged billet, and then the pre-disc portion is used as a disc portion, and the pre-outer rim portion is used as an outer portion. The wheel manufacturing method according to any one of (15) to (17), wherein the rim portion is used and the pre-inner rim portion is used as the inner rim portion.
Here, extrusion forging is included in closed forging. Extrusion forging includes forward extrusion forging and backward extrusion forging. A product obtained by extrusion is continuously formed in a fixed shape, and by using a forged billet, the crystal grain size of the metal structure can be reduced.

According to the present invention, (19) the outer rim portion and the inner rim portion are formed by machining forging a forged billet and then removing a forging margin by a milling machine including a lathe or a machining center. It exists in the manufacturing method of the wheel as described in any one.

The present invention includes (20) a forging process for forging a billet into a semi-finished product, and performing a machining process by boring, a milling machine including a lathe, a machining center, etc. 15) It exists in the manufacturing method of the wheel as described in any one of (17).

According to the present invention, (21) a pre-inner rim portion is formed by extrusion forging on a forged billet and pressed with a rolling roller from an oblique direction in a state where a gap is provided between the pre-inner rim portion and a mold. The wheel manufacturing method according to any one of (15) to (17), wherein the inner rim portion is formed by spinning.

According to the present invention, (22) any one of the above (15) to (17), wherein the disk portion, the outer rim portion or the inner rim portion is individually forged using a forged billet and integrated by a coupling means. It exists in the manufacturing method of the wheel of description.

The present invention is (23) forging a disk part, an outer rim part or an inner rim part using a forged billet, and casting or forging the other parts not formed by forging with an aluminum alloy other than duralumin and combining them. The wheel manufacturing method according to any one of the above (15) to (17) integrated by means.

In the forged billet of the present invention, the crystal grain size of the metal structure is refined by compressing and compressing a cast billet made of duralumin. Therefore, for example, when forging is performed using a refined forged billet to form a forged product (for example, a wheel) having a complicated shape, the metal of the forged billet, even in a portion that is only partially stretched Since the structure has already been refined, the resulting forged product has a fine crystal grain size as a whole. For this reason, according to the forged billet, it is possible to produce a forged product with excellent mechanical strength and uniform mechanical strength, or a forged product (finished product or semi-finished product) that performs machining after forging. It becomes.

In general, duralumin is poor in corrosion resistance because it contains a large amount of copper. However, in the forged billet, the proportion of crystal grain boundaries and grain boundary precipitates, which are considered to be the cause, is reduced, so that corrosion resistance can be improved. . Generally, since 2000 series duralumin contains a lot of copper, when an aqueous solution or the like is in contact with the metal surface, an anode portion and a cathode portion are locally generated by a potential difference to constitute a local battery, and there is a portion corresponding to the anode portion. It is easy to corrode. The main cause is that an electrolyte such as an aqueous solution permeates along the crystal grain boundaries and precipitates of the metal structure, and the residual stress is also applied, thereby making it easy to generate a local battery, progressing corrosion, and generating cracks. On the other hand, in the forged billet of the present invention, by reducing the crystal grain size, the ratio of crystal grain boundaries and precipitates is reduced by 50% to 80%, so that the stress corrosion cracking property can be greatly improved. . The effect of suppressing the progress of stress corrosion cracking is expected because the fiber structure is subdivided by reducing the crystal grain size.

In the forged billet, the mechanical strength is further improved by using duralumin as the forged billet. And when a forge billet is equipped with the physical property mentioned above, all the forged products using a forge billet can exhibit sufficient mechanical strength.

In the method for producing a forged billet according to the present invention, the forging ratio (H1 / H2) is preferably 4.0 or more. By setting it as this forging ratio, since the crystal grain diameter of a forge billet can be further refined | miniaturized, mechanical strength can further be improved.

In the forged billet manufacturing method, a cast billet made of duralumin is pressure-compressed in one direction to form a pre-forged billet, and further compressed in a direction different from the direction in which the pre-forged billet is compressed. If it is, the proportion of the structure having a small crystal grain size in the entire metal crystal particle becomes large. Thereby, it is possible to produce a forged product having better mechanical strength and uniform mechanical strength. Since the cast billet is duralumin, the material flow of the outer portion of the forged billet can be positively performed by further compressing and compressing the outer portion to deform it. Thereby, even if the forged billet obtained is duralumin, the particle size of the metal crystal particles in the central portion and the particle size of the metal crystal particles in the other portions are approximately the same, and uniform refinement is possible. As a result, it is possible to greatly improve the material yield when almost all of the cast billet is made of forged billets, and the forged product via the pre-forged billet exhibits a uniform mechanical strength and impact resistance. It becomes a high quality thing.

Since the finished product or semi-finished product of the present invention is formed using the forged billet described above, it has sufficient mechanical strength. Note that if the finished product or semi-finished product is forged using a forged billet, the forging ratio is higher than the mechanical strength of the forged billet itself, so that it becomes stronger.
Moreover, since sufficient mechanical strength is provided, weight reduction can be achieved, maintaining mechanical strength by reducing the thickness or volume of a finished product or a semi-finished product.

The wheel manufacturing method of the present invention uses the forged billet described above, and the Charpy impact value of the disk portion, outer flange portion, inner rim portion, and inner flange portion is 30 J / cm ² or more. Have
Moreover, since sufficient mechanical strength is provided, weight reduction can be achieved, maintaining mechanical strength by reducing the thickness or volume of a wheel.

For example, when the wheel obtained by the method for producing a wheel of the present invention and an A6000 series wheel made of an A6000 series aluminum alloy have the same mechanical strength, the wheel is at least more than an A6000 series wheel made of an A6000 series aluminum alloy. The weight can be reduced by 10% or more.
Further, the average thickness of the well portion and the inner rim portion is 1.8 to 2.5 mm, the average thickness of the hub portion is 35 to 66 mm, and a wheel and an A6000 series wheel made of an A6000 series aluminum alloy are provided. In the case of having the same mechanical strength, the wheel can be reduced in weight by at least 15% or more than the A6000 series wheel made of the A6000 series aluminum alloy.

Furthermore, since the above-mentioned wheel has extremely high toughness, even if the rim part (inner rim part, outer rim part) or the disk part of the light alloy wheel is cracked for some reason during vehicle running, Does not grow at a stretch. In this case, the tire pressure gradually decreases and the operator notices abnormally, so that it does not lead to a major accident. Therefore, safety can be ensured by using such a wheel.

In the wheel manufacturing method, when the pre-outer rim part and the pre-inner rim part are formed by extrusion forging, secondary recrystallization is generated between the hump part, the well part, and the inner flange part. Almost uniform crystal grain size can be formed.

In particular, when spinning the pre-inner rim portion, it is preferable to form the inner rim portion by pressing with a rolling roller from an oblique direction in a state where a gap is provided between the pre-inner rim portion and the mold. When spinning is performed using a forged billet with a refined crystal grain size, the use of a forged billet with increased mechanical strength increases the pressing force of the rolling roller and tends to cause secondary recrystallization. On the other hand, in the case described above, since the gap is provided and pressed by the rolling roller from the oblique direction, secondary recrystallization of the inner rim portion can be suppressed.

FIG. 1 is a perspective view showing a first embodiment of a forged billet according to the present invention. FIG. 2 is a cross-sectional view showing a forged billet according to the first embodiment and a cast billet before pressure compression. FIGS. 3A and 3B are cross-sectional views showing a state where the cast billet before pressure compression is a forged billet according to the first embodiment by closed forging. FIGS. 4A to 4D are cross-sectional views showing an example in which a cast billet is compressed and compressed a plurality of times to obtain a forged billet according to the present invention. 5A and 5B are cross-sectional views showing forward extrusion forging in the wheel manufacturing method according to this embodiment. FIGS. 6A and 6B are cross-sectional views illustrating the backward extrusion forging process in the wheel manufacturing method according to the present embodiment. FIGS. 7A and 7B are cross-sectional views showing the flaring process in the wheel manufacturing method according to the present embodiment. (A) of FIG. 8 is sectional drawing which shows the 1st spinning process in the manufacturing method of the wheel which concerns on this embodiment, (b) And (c) is sectional drawing which shows a 2nd spinning process. FIG. 9A is a front view showing a wheel obtained by the wheel manufacturing method according to the present embodiment, and FIG. 9B is a cross-sectional view taken along the line I-I ′ of FIG. (A) and (b) of Drawing 10 is a figure showing an example of a wheel obtained by a manufacturing method of a wheel concerning this embodiment, and an A6000 system wheel which has the same mechanical strength as the wheel. FIG. 11 is a perspective view showing a second embodiment of the forged billet according to the present invention. FIGS. 12A to 12D are a top view and a side view showing the manufacturing process of the forged billet according to the second embodiment. FIGS. 13A to 13E are schematic views for explaining the effect when the cast billet is compressed and compressed in one direction and further compressed and compressed in different directions. FIGS. 14A to 14F are a top view and a side view showing a manufacturing process of the forged billet according to the third embodiment. FIG. 15 is a schematic view illustrating a manufacturing process of a forged billet according to the fourth embodiment. FIG. 16 is a schematic view showing a manufacturing process from a forged billet to a wheel according to another embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

[First Embodiment]
FIG. 1 is a perspective view showing a first embodiment of a forged billet according to the present invention.
A forged billet 10 according to the first embodiment shown in FIG. 1 includes a cylindrical main body 1.

The average particle size of the metal crystal particles of the forged billet 10 is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 15 μm or less.
When the average particle size exceeds 30 μm, the mechanical strength may be insufficient as compared with the case where the average particle size is in the above range. In this specification, “average particle diameter” is a value measured based on the cutting method of JIS-H0542. Further, the measurement site is the forged billet and each part of the wheel, both near the center.

The Charpy impact value of the forged billet 10 is preferably 30 J / cm ² or more, more preferably 35 J / cm ² or more, and further preferably 40 J / cm ² or more. The Charpy impact value is a value measured according to JIS-Z2242. Such Charpy impact value is one of the materials for judging whether the impact resistance is superior or inferior, and shows the possibility of absorbing impact energy.
By setting the Charpy impact value to 30 J / cm ² or more, the forged product (finished product or semi-finished product) using the forged billet 10 can exhibit sufficient mechanical strength.

The tensile strength of the forged billet 10 is preferably 400 MPa or more. The tensile strength is a value measured according to JIS-Z2241.
The 0.2% proof stress of the forged billet 10 is preferably 150 MPa or more, and more preferably 300 MPa or more. The proof stress is a value measured according to JIS-Z2241.
The elongation of the forged billet 10 is preferably 8% or more, and more preferably 20% or more. The elongation is a value measured according to JIS-Z2241. The elongation is the rate at which the material stretches in the tensile test of the material. When the starting point distance of the test piece is L ₀ and the breaking point distance is L ₁ , the elongation is expressed by the following formula. It is.
δ = [(L ₁ −L ₀ ) / L ₀ ] × 100
This shows the elongation rate until breakage, and shows the range in which the shape of the wheel is maintained.
The Brinell hardness of the forged billet 10 is preferably 65HB or more. The Brinell hardness is a value measured according to JIS-Z2243.

The forged billet 10 preferably has forged lines.
Here, the forging line means a state of a flow of metal crystal particles generated in a forged product in a metal structure and having a crystal grain size of at least 12 μm. In this forged streamline, the flow of the metal structure becomes clearer when the crystal grain size of the metal crystal particles becomes finer than 9 μm by pressure compression.
In the forged billet 10, it is preferable that the forged stream lines extend radially from the center of the cylinder.

When the forging billet 10 has a forged line, the forged product obtained has a forged line even if forging is performed based on a known method. As a result, the forged product has a uniform mechanical strength. Note that the forged product (finished product or semi-finished product) using the forged billet 10 has a forged line even if it is a portion that is not compression-forged in the subsequent forging process, so the mechanical strength is reliable. To improve.

The light metal alloy is made of duralumin. In the forged billet 10, mechanical strength is further improved by using duralumin as the forged billet.
Specific examples of duralumin include Al—Zn—Mg (7000), Al—Cu—Mg (2000) such as A2014 and A2017, and the like.
Among these, Al—Cu—Mg (2000) is preferable from the viewpoint of versatility.

Next, the manufacturing method of the forge billet 10 is demonstrated.
FIG. 2 is a cross-sectional view showing a forged billet according to the first embodiment and a cast billet before pressure compression.
As shown in FIG. 2, the forged billet 10 is obtained by compressing and compressing the cast billet 4 in the axial direction (one direction).

The casting billet 4 is obtained by heating and melting a light metal alloy at, for example, 700 ° C. or more and casting in an inert gas atmosphere.

Examples of the inert gas include nitrogen and argon. That is, by removing oxygen, it is possible to prevent the molten raw material (hereinafter referred to as “molten raw material”) from being oxidized.

The casting method is not particularly limited, and examples thereof include a sand casting method, a gypsum casting method, a precision casting method, a die casting method, a centrifugal casting method, and a continuous casting method.
Among these, the casting method is preferably a continuous casting method. In this case, the forged billet 10 having a more uniform crystal grain size of the metal crystal particles can be obtained.

In casting, the molten raw material is poured into a casting machine at a speed of, for example, 65 to 90 mm / min.
When the casting speed is less than 65 mm / min, the crystal grain size of the metal crystal particles tends to be non-uniform compared to the case where the speed is within the above range, and the casting speed is 90 mm / min. When it exceeds, there exists a possibility that it may be damaged at the time of casting billet manufacture compared with the case where speed exists in the said range.

The molten raw material poured into the casting machine is homogenized, for example, by being heated at 450 ° C. or higher for 6 hours or longer.
And it cools after that and the cylindrical cast billet 4 is obtained.
Here, the cooling is preferably rapid cooling. In this case, there is an advantage that crystal grains become fine. In addition, you may cut | disconnect the obtained cylindrical cast billet 4 in the orthogonal | vertical direction with respect to an axial direction as needed.

The resulting cast billet 4 preferably has a length / diameter ratio of 2.0 to 2.5. In this case, when the cylindrical cast billet 4 is pressed in the axial direction, it is possible to suppress the occurrence of a buckling phenomenon in which the cast billet 4 is bent suddenly.

Since the forged billet 10 is obtained by compressing the cast billet 4 in the axial direction, the crystal grain size of the metal crystal particles is refined at the stage of the forged billet 10. For this reason, the wheel which became a product using this as a starting material also maintains the crystal grain size, and at least the crystal grain size of the metal crystal particles becomes finer.
Incidentally, in view of the relationship between the hole and the petch represented by the following formula, the strength and impact resistance (Charpy impact value) of the material increase when the metal structure is refined by pressure compression.
σ = σ ₀ + kd ^−1/2
In the formula, σ represents yield stress or deformation stress, d represents the average crystal grain size of the metal structure, and σ ₀ and k represent constants determined by the material.

In the forged billet of the invention in the first embodiment, the metal structure is refined by pressurizing and compressing the cast billet made of duralumin, for example, forging using the refined forged billet 10, In the case of a forged product having a complicated shape (for example, a wheel), the metal structure of the forged billet 10 has already been refined even in a portion that is only partially stretched. As a whole, the crystal grain size of the metal structure becomes fine. For this reason, according to the said forge billet, it becomes possible to manufacture the forge product with which mechanical strength is excellent and mechanical strength is uniform.

Here, examples of the method for compressing and compressing the cast billet 4 include free forging, die forging, swing forging, extrusion forging, rotary forging, closed forging, and section forging. Note that die forging includes press forging and hammer forging. Also, partial forging can be used in which a casting billet is rotated by a certain angle and a part of pressure is repeatedly applied.
Among these, it is preferable that pressure compression is based on closed forging, swing forging, hammer forging, section forging, or free forging.

FIGS. 3A and 3B are cross-sectional views showing a state where the cast billet before pressure compression is a forged billet according to the first embodiment by closed forging.
As shown in FIGS. 3A and 3B, in closed forging, when the casting billet 4 is compressed in the axial direction, the metal structure can be prevented from spreading in the lateral direction. That is, by adding the lateral restraining force P, the forged billet 10 can be prevented from becoming a drum shape swelled in the middle part, and the crystal grain size of the metal crystal particles can be made finer.

The processing conditions at this time may be any of hot forging, warm forging, cold forging, and isothermal forging.
Among these, the processing conditions are preferably hot forging. Specifically, the pressure compression is preferably performed under a temperature condition of 300 to 550 ° C. and a pressure condition of 9.8 × 10 ³ kN to 88.2 × 10 ³ kN. The pressure of 9.8 × 10 ³ kN to 88.2 × 10 ³ kN is 1000 to 9000 tons when converted to the thrust scale of the forging machine (press machine).

Thus, the cast billet 4 is pressurized and compressed, and then cooled to obtain a cylindrical forged billet 10. The cooling is preferably rapid cooling.

The forging billet 10 according to the first embodiment preferably has a forging ratio satisfying the following formula in the pressure compression.
H1 / H2 ≧ 4.0
In the formula, H1 means the length in the direction in which the cast billet 4 is compressed and compressed, that is, the height in the axial direction of the cast billet 4, and H2 is the length in the direction in which the forged billet 10 is compressed and compressed. That is, it means the height of the forged billet 10 in the axial direction (see FIG. 2). In addition, when pressurizing and compressing a plurality of times, H1 means the length of the cast billet 4 in the direction before being compressed and compressed, and H2 is the final forged billet 10 that has been compressed and compressed a plurality of times. It means the length in the direction of pressure compression at the end.

When the light metal alloy is duralumin, the particle diameter of the metal crystal particles is extremely refined as the H1 / H2 (forging ratio) by pressure compression increases from 3.5.
Further, the H1 / H2 (forging ratio) is preferably 4.0 or more, more preferably 4 to 12 because it is surely refined, and 4 to 6 from the viewpoint of practicality. More preferably. Since the forged billet 10 is an intermediate product, it is expected that the forging ratio further increases when the forged product is forged using the forged billet 10.

Here, when it is set as the forge billet of a high forging ratio, it is preferable to compress and compress several times. If trying to make a forged billet with a high forging ratio in one stage, buckling may occur.
FIGS. 4A to 4D are cross-sectional views showing an example in which a cast billet is compressed and compressed a plurality of times to obtain a forged billet according to the present invention.
First, as shown in FIG. 4 (a), when the casting billet 4 is closed and forged, a mold 51 having a cylindrical hole 51a that covers at least half the height of the casting billet 4 and preferably covers the entire height. Closed forging is performed using Next, as shown in FIG. 4B, closed forging is performed using a mold 52 in which a cylindrical hole 52a covering the half or more of the pre-forged billet 12a is formed in the same manner. As shown in the figure, closed forging is performed using a mold 53 in which a cylindrical hole 53a that covers more than half of the pre-forged billet 12b is formed in the same manner as shown in FIG. Closed forging is performed using a mold 54 in which a cylindrical hole 54a that covers more than half of the billet 12c is formed. Thus, the forged billet 10 is obtained.

Such forged billet 10 is suitably used for vehicle wheel manufacturing. Besides, it is suitably used for flying parts, transportation equipment parts, industrial equipment parts, equipment for building materials including sashes, and members for these uses. Specifically, aircraft It is suitably used for manufacturing wheels of industrial wheels, flying objects such as airplanes and helicopters, transportation equipment parts such as trucks, industrial equipment parts such as machine tools and electrical appliances.

Next, the manufacturing method of the wheel 3 using the forge billet 10 is demonstrated.
The manufacturing process from the forged billet to the wheel includes a forging process, a heat treatment process, and a finishing process.
The forging process is a process of forming a semi-finished product from a forged billet by extrusion forging (forward extrusion forging method, backward extrusion forging method). In the present embodiment, the semi-finished product means a pre-wheel. Further, the Charpy impact value of the semi-finished product is preferably 30 J / cm ² or more, more preferably 35 J / cm ² or more, and further preferably 40 J / cm ² or more.

In the above wheel manufacturing method, the pre-outer rim part and the pre-inner rim part are formed by an extrusion forging method, so that recrystallization of metal crystal particles is generated from the hump part to the well part and the inner flange part. Almost uniform crystal grain size can be formed.

5A and 5B are cross-sectional views showing forward extrusion forging in the wheel manufacturing method according to this embodiment. The forward extrusion forging process is a process in which a forward extrusion forging process is performed on the forged billet 10 to form a prewheel (hereinafter referred to as “first prewheel” for convenience) 3b.
As shown in FIG. 5A, in the forward extrusion forging process, first, the forging billet 10 is placed between the upper die 16 and the lower die 17 provided with the knockout portion 17a. Here, the knockout part 17a is for pushing up and taking out the first pre-wheel 3b after forward extrusion forging.

As shown in FIG. 5B, the upper die 16 is lowered, and a portion of the forged billet 10 is pushed into the gap between the knockout portion 17 a and the lower die 17. Thereby, the pre-rim part 5 and the pre-disc part 14 are formed.
And the 1st prewheel 3b is obtained by raising knockout part 17a.

FIGS. 6A and 6B are cross-sectional views illustrating the backward extrusion forging process in the wheel manufacturing method according to the present embodiment. The backward extrusion forging process is a process in which the backward extrusion forging process is performed on the first pre-wheel 3b and the pre-rim portion 5 is extended.
As shown in FIG. 6 (a), in the backward extrusion forging process, first, the first pre-wheel 3b is placed between the upper mold 18 and the lower mold 19 provided with the knockout portion 19a. . Here, the knockout part 19a is for pushing up and taking out the pre-wheel (hereinafter referred to as “second pre-wheel” for convenience) 3c after backward extrusion forging.

As shown in FIG. 6B, the upper mold 18 is lowered, and a part of the first pre-wheel 3 b is pushed into the gap between the upper mold 18 and the lower mold 19. As a result, the pre-disc portion 14 having a design surface including irregularities such as spokes is formed, and at the same time, the pre-rim portion 5 is extended to form the pre-inner rim portion 8b. The pre-inner rim portion 8b is formed by extruding the surplus material of the pre-disc portion 14 so as to be extended.
And the 2nd prewheel 3c is obtained by raising knockout part 19a.

Here, in the backward extrusion forging, since the traveling direction of the upper mold 18 and the extending direction of the pre-rim portion 5 are opposite directions, the resistance due to friction is large. For this reason, since the further pressurization force is required, it is preferable to extend the pre-rim part 5 linearly with a predetermined inclination angle. Then, a part of recrystallization can be prevented.

7 (a) and 7 (b) are cross-sectional views showing the flaring process in the wheel manufacturing method according to this embodiment. In the flaring process, the outer rim portion 7 is formed by flaring the pre-outer rim portion 7b. In the flaring process, it is also preferable to adjust the pre-inner rim portion 8b. Further, when a reinforcing structure that protrudes toward the inner diameter side of the rim flange is formed on the inner rim flange portion 8a, an extra wall is provided in advance in the pre-inner rim portion 8b in consideration of the draft angle of the mold, What is necessary is just to excise this surplus wall and to form a reinforcement structure. Further, flaring of the pre-outer rim portion 7b is not necessary since the outer rim portion can be formed at a predetermined spread angle during extrusion forging if the mold 19 is a split die.

7A, in the flaring process, first, the second pre-wheel 3c is placed between the upper mold 25 and the lower mold 26 provided with the knockout portion 26a. Here, the knockout part 26a is for pushing up and taking out the pre-wheel after the flaring process (hereinafter referred to as "third pre-wheel" for convenience) 3d.

As shown in FIG. 7B, the upper mold 25 is lowered, the pre-outer rim portion 7b of the second pre-wheel 3c is pressed, and flaring (expanded) outward. At this time, the pre-inner rim portion 8b is expanded around the inner flange portion 8a.
Thereby, the 3rd pre wheel 3d is obtained.

The heat treatment step is a step of heat treating the third pre-wheel 3d. When the light metal alloy is duralumin, the heat treatment is performed under heat treatment conditions such as T3, T4, T6, T73 based on JIS-H0001. Specifically, solution treatment is performed at 450 to 510 ° C. for 3 to 5 hours, and quenching (water cooling) is performed for 3 to 7 minutes. At room temperature, 96 hours or more, or 150 to 200 ° C. for 7 to 9 hours. Artificial aging treatment is performed.

In the wheel manufacturing method according to the present embodiment, the pre-wheels 3b to 3d are obtained by the forging process described above.
Since the pre-wheels 3b to 3d are obtained by forging the forged billet 10, they have sufficient mechanical strength.
Moreover, since sufficient mechanical strength is provided, weight reduction can be achieved, maintaining mechanical strength by reducing the diameter etc. of the prewheel 3a itself.

Next, the obtained third pre-wheel 3d is subjected to a finishing process on the pre-inner rim portion 8b erected on the periphery.
Examples of the finishing process include machining such as spinning, drilling, cutting, and milling. That is, the third pre-wheel 3d is machined to remove a forging margin by a milling machine including a lathe or a machining center.
Here, the forging margin means a thick portion for avoiding contact between dies, and includes burrs and the like.

The spinning process is a process of forming the inner rim part 8 by narrowing down the pre-inner rim part 8b of the third pre-wheel 3d, and the drilling process is performed by drilling a hole in the third pre-wheel 3d at the machining center. This is a process for forming the portion 11 and the pattern, and the cutting process is a process for forming the outer rim part 7 by cutting the periphery of the pre-wheel 3a with a lathe. The milling process is performed by cutting out substantially the entire wheel 3. It is a process that performs molding.

As a finishing process, first, a spinning process is performed. That is, in the spinning process, the outer rim portion 7 and the outer flange portion 7a extended in the surface direction of the third pre-wheel 3d by narrowing a part while spinning the pre-inner rim portion 8b, The inner rim portion 8 and the inner flange portion 8a that are erected in the vertical direction around the periphery of the pre-wheel 3a are formed. At this time, a finishing margin may be formed at the same time.

(A) of FIG. 8 is sectional drawing which shows the 1st spinning process in the manufacturing method of the wheel which concerns on this embodiment, (b) And (c) is sectional drawing which shows a 2nd spinning process.
As shown in FIGS. 8A, 8 B, and 8 C, in the wheel manufacturing method according to this embodiment, the spinning process includes a first spinning process and a second spinning process.
The third pre-wheel 3d uses a forged billet having a high forging ratio, and has a high toughness because the tensile strength, Charpy impact value, elongation, and the like are significantly improved. For this reason, in the manufacturing method of the wheel concerning this embodiment, in order to avoid imposing a considerable burden on a rolling roller by plastic deformation by spinning processing, the 1st spinning processing and the 2nd spinning processing are provided.

As shown in FIG. 8A, in the first spinning process, the first spinning device 31 includes an inner mold 31a and an outer mold 31b that can sandwich the third pre-wheel 3d, and a pre-inner rim portion 8b. And a plurality of rolling rollers 35 for narrowing down.
In the first spinning process, the third pre-wheel 3d is securely fixed by being sandwiched between the inner mold 31a and the outer mold 31b, and these rotate together. At this time, by pressing the plurality of rolling rollers 35 against the pre-inner rim portion 8 b, the pre-inner rim portion 8 b is rolled and becomes a rough shape of the inner rim portion 8.

As shown in FIG. 8B, in the second spinning process, the second spinning device 32 includes an inner mold 32a and an outer mold 32b that can support the third pre-wheel 3d, and a pre-inner rim portion 8b. A plurality of rolling rollers (not shown) for further narrowing down are provided.
In the second spinning process, the third pre-wheel 3d is attached to the outer mold 32b, and the tip of the pre-inner rim portion 8b of the third pre-wheel 3d is supported by the inner mold 32a. That is, a gap 38a is provided between the third pre-wheel 3d and the inner mold 32a, and a gap 38b is provided between the pre-inner rim portion 8b and the inner mold 32a. In the second spinning process, the inner mold 32a is an assembled mold.

Then, in the state of FIG. 8B, as shown in FIG. 8C, the inner flange portion is pressed by pressing the pre-inner rim portion 8b with the rolling roller 35 from the oblique direction (for example, 45 ° direction). 8a is molded. At this time, it is preferable that the

gaps

38a and 38b are maintained.

In the manufacturing method of the wheel 3, since the

gaps

38a and 38b are provided, there is an advantage that no stress is pushed up from below even when pressed by a rolling roller. In addition, as described above, since the pressing is performed by the rolling roller 35 from the oblique direction, the secondary recrystallization of the metal crystal particles in the inner rim portion 8 can be reliably suppressed. That is, when the forging billet 10 having a refined crystal grain size is used for spinning, if the forging billet 10 having high mechanical strength is used, the pressing force of the rolling roller 35 is increased, and the metal crystal particles Although there is a drawback that recrystallization is likely to occur, recrystallization of the metal crystal particles in the inner rim portion 8 can be suppressed by providing a gap and pressing with a rolling roller 35 from an oblique direction. The number of rolling rollers 35 is not particularly limited. If there are a plurality of them, one of them may be pressed from the oblique direction.

Next, with respect to the prewheel 3a formed with the outer rim portion 7 and the inner rim portion 8, the pattern of the disk portion 6 is formed by drilling, and the periphery of the prewheel 3a is cut by cutting. A wheel 3 is obtained. In addition, the pattern formation of the disk part may be performed by forming a spoke part or the like by forging in advance, and cutting the remaining forging margin of the web thickness by machining to form a hole, or forging the disk part into a disk shape. After forming, a pattern such as spokes may be formed by drilling by machining.
According to the manufacturing method of the wheel 3 according to the present embodiment, the lightened wheel 3 is excellent in design by forming irregularities and voids. If necessary, chemical surface treatment, plating, shots, painting, and the like may be performed.

Next, the wheel 3 obtained by the wheel manufacturing method according to the present embodiment will be described.
FIG. 9A is a front view showing a wheel obtained by the wheel manufacturing method according to this embodiment, and FIG. 9B is a cross-sectional view taken along the line II ′ of FIG.
The wheel 3 (multi-piece) includes a disk portion 6, and an outer rim portion 7 and an inner rim portion 8 provided on the periphery of the disk portion 6. That is, the wheel 3 includes a disk portion 6, an outer rim portion 7 connected to the periphery of the disk portion 6 and extending in the surface direction of the disk portion 6, and a surface of the disk portion 6 connected to the periphery of the disk portion 6. And an inner rim portion 8 erected in the vertical direction.

The disk portion 6 includes a disk-shaped hub portion 6a and a spoke portion 11 extending from the hub portion 6a in a radial Y shape. That is, in the wheel 3, the outer rim portion 7 and the inner rim portion 8 are connected to the tip of the spoke portion 11. The hub portion 6a is preferably a gently curved surface. In this case, since the flow of the raw material at the time of pressing becomes uniform, the training ratio is more equalized.
The hub portion 6a has a disk shape having a curved surface whose surface is gently curved, and is provided with a bolt insertion hole 6b for inserting a bolt when the wheel 3 is fixed to the axle with a bolt.
In addition, an empty portion 9 is provided between the adjacent spoke portions 11.
The inner rim portion 8 has an inner flange portion 8a formed at the tip, and the outer rim portion 7 has an outer flange portion 7a formed at the tip.

The forging ratio of the wheel 3 to the cast billet 4 (hereinafter referred to as “total forging ratio” for convenience) is preferably 4.0 or more, and 5.5 or more when the light metal alloy is a magnesium alloy. Is preferred.
Here, the total forging ratio is obtained by multiplying the forging ratio of the forged billet 10 with respect to the above-described casting billet 4 by the forging ratio of the wheel 3 with respect to the forged billet 10. That is, the total training ratio is a value represented by “the height H1 of the cast billet 4” ÷ “the height H3 of the wheel 3”. The height H3 of the wheel 3 is shown in FIG. The wheel height H3 is calculated as the average of the heights of the respective parts of the wheel in the forged direction.

In the wheel 3, since the starting material is the forged billet 10 described above, when the average particle size of the metal crystal particles of the forged billet 10 is 30 μm or less, the wheel 3 is selected from the group consisting of the inner rim portion 8 and the inner flange portion 8 a. The average particle size of the metal crystal particles based on the cutting method based on JIS-H0542 in at least one portion is 30 μm or less. The average particle size is more preferably 5 to 20 μm, still more preferably 5 to 15 μm.
The average particle size excluding the recrystallized portion of the metal crystal particles of the inner rim portion 8 based on the cutting method based on JIS-H0542 is preferably 20 μm or less.
In these cases, the wheel 3 is unlikely to be damaged when an unexpected situation occurs when the vehicle travels and an impact stress is applied to the rim portion.

In the wheel 3, the Charpy impact value of the disk portion 6 (the bubb portion 6a and the spoke portion 11), the outer flange portion 7a, the inner rim portion 8 and the inner flange portion 8a is preferably 30 J / cm ² or more, and 35 J / cm. more preferably ² or more, further preferably 40 J / cm ² or more.
The tensile strength of the wheel 3 is preferably 400 MPa or more.
The proof stress of the wheel 3 is preferably 250 to 400 MPa.
The elongation of the spoke part 11, the outer flange part 7a, the inner rim part 8 and the inner flange part 8a of the wheel 3 is preferably 15 to 20%.
The Brinell hardness of the wheel 3 is preferably 65 HB or more.

Since the wheel 3 is manufactured by forging using the forged billet 10 described above as a starting material, the wheel 3 has excellent mechanical strength and uniform mechanical strength. In addition, since the disk part 6, the outer rim part 7, and the inner rim part 8 are united (one piece), the wheel 3 has better mechanical strength and more uniform mechanical strength. Become.
Moreover, since sufficient mechanical strength is provided, weight reduction can be achieved, maintaining mechanical strength by making each part volume of the wheel 3 small.

For example, when the wheel 3 and the conventional A6000 series wheel made of an A6000 series aluminum alloy have the same mechanical strength, the wheel 3 is at least 10% lighter than the A6000 series wheel made of an A6000 series aluminum alloy. be able to.
Further, the average thickness of the well portion and the inner rim portion is 1.8 to 2.5 mm, the average thickness of the hub portion is 35 to 66 mm, the wheel 3 and an A6000 series wheel made of an A6000 series aluminum alloy, Have the same mechanical strength, the wheel 3 can be reduced in weight by at least 15% or more than an A6000-based wheel made of an A6000-based aluminum alloy.

(A) and (b) of Drawing 10 is a figure showing an example of a wheel obtained by a manufacturing method of a wheel concerning this embodiment, and an A6000 system wheel which has the same mechanical strength as the wheel. In FIG. 10, T-057 drawn with a solid line represents the

wheel

3, and 19 "RG-R drawn with a two-dot chain line represents an A6000 series wheel.
As shown in FIG. 10, by reducing the average thickness of the well portion, inner rim portion, and hub portion of the wheel 3, the weight is reduced by about 20% compared to the A6000 series wheel.
Surprisingly, the weight-reduced wheel is JIS
In the rotating bending fatigue test based on D 4103, when the specified value was 100,000 times with a load of 3454 N · m, the weight-reduced wheel achieved 9.3 million times.

The wheel 3 is suitably used for, for example, a vehicle or an aircraft wheel. In particular, when used for a vehicle, the automobile can be reduced in weight, so that the environmental load caused by gasoline or the like can be reduced during driving, and the cost can be reduced.

[Second Embodiment]
FIG. 11 is a perspective view showing a second embodiment of the forged billet according to the present invention.
A forged billet 10a according to the second embodiment shown in FIG. 11 is different from the forged billet 10 according to the first embodiment in that the forged billet 10a includes a polygonal column, that is, a hexagonal columnar main body 1 here. The wheel and the wheel manufacturing method are the same as described above.

When the forged billet 10a has a hexagonal column shape, the forged billet can be accurately positioned when the forged billet is processed, so that the flow of the metal crystal particles can be made constant.

FIGS. 12A to 12D are a top view and a side view showing the manufacturing process of the forged billet according to the second embodiment.
As shown in FIG. 12 (a), the forged billet 10a is obtained by first casting a light metal alloy into a cylindrical cast billet 4, and this cast billet 4 is axially closed by closed forging using a hexagonal column mold. A pre-forged billet 12 shown in FIG.
Next, as shown in FIG. 12C, the obtained pre-forged billet 12 is erected with the side face down. Then, the pre-forged billet 12 is again pressed and compressed from the direction P2, which is different from the axis, that is, the vertical direction, by closed forging using a hexagonal column mold to obtain a forged billet 10a shown in FIG. At this time, since the pre-forged billet 12 has a hexagonal column shape, it is easy to position the pre-forged billet 12 with one side face down. That is, it is easy to press and compress in a direction different from the direction in which the pressure is compressed.

Thus, in the production of the forged billet 10a according to the second embodiment, the forged billet 10a as a starting material pressurizes and compresses the cast billet 4 in one direction to form the pre-forged billet 12, and the pre-forged billet 12 Since it is obtained with a history of further pressing and compressing in a direction different from the direction in which the metal is pressed and compressed, the proportion of the structure having a small crystal grain size in the entire metal crystal particles of the forged billet 10a made of duralumin increases. That is, the forged billet obtained by pressure-compressing the cast billet has a smaller crystal grain size due to the flow of the metal structure. In addition to this, in the forged billet 10a, the metal structure moves in different directions because it is compressed and compressed a plurality of times in different directions, and the crystal grain size becomes smaller. For this reason, it is possible to manufacture a wheel having better mechanical strength and more uniform mechanical strength.

Here, when pressure-compressed in one direction, the metal crystal particles in the middle portion (so-called central portion) are refined (hereinafter referred to as “fine regions”), and the upper and lower ends are made fine in metal crystal particles. Region (hereinafter referred to as “NG region”) occurs. In addition, a forge line is generated in the finely divided region in the middle part.
On the other hand, as described above, by further compressing and compressing the pre-forged billet in a direction different from the direction in which the pre-forged billet is compressed and compressed, a part of the NG region is further miniaturized. be able to.

FIGS. 13A to 13E are schematic views for explaining the effect when the cast billet is compressed and compressed in one direction and further compressed and compressed in different directions.
First, as shown in FIG. 13A, when the cast billet 4 is compressed and compressed, the middle portion becomes the fine region A and the upper and lower ends become the NG region B.
Then, when the side of this is stood down and pressed and compressed again from above, as shown in FIG. 13B, the middle part becomes the fine region A, and the fine region A in FIG. Remain. That is, the corners in the four directions become the NG region B.
Further, when the side face is set up downward and compressed again from above, as shown in FIG. 13 (c), the middle part becomes the fine region A, and (a) in FIG. The fine area A of b) remains. That is, the corners in the eight directions become the NG region B.
Further, when the side of this is stood down and pressed and compressed again from above, as shown in FIG. 13 (d), the side of this is stood down and pressed again from above. When compressed, the result is as shown in FIG. That is, the NG region B can be reduced stepwise by repeating the pressure compression from different directions.
Thus, after compressing and compressing the cast billet in one direction and then compressing and compressing in a different direction, the proportion of the fine region A increases, and by repeating this, the proportion of the fine region A increases stepwise. To go. By utilizing this phenomenon, the effective use area of the forged billet can be increased, and the yield of the material can be greatly improved. Actually, 95% becomes the fine region A and 5% becomes the NG region by at least five pressurizations and compressions.

[Third Embodiment]
FIGS. 14A to 14F are a top view and a side view showing a manufacturing process of the forged billet according to the third embodiment.
The forged billet 10b according to the third embodiment is different from the forged billet 10a according to the second embodiment in that the pre-forged billet passes through a hexagonal columnar lens shape or a truncated cone shape. The wheel and the wheel manufacturing method are the same as described above.

As shown in FIG. 14 (a), the forged billet 10b is a cylindrical pre-forged billet 13a by first compressing and compressing a cylindrical cast billet 4 in the axial direction by flat-pressing closed forging. .

Next, as shown in FIG. 14 (b), the pre-forged billet 13a is pressure-compressed in the axial direction by closed forging using a hexagonal column lens-shaped die to obtain a pre-forged billet 13b. The pre-forged billet 13b has a hexagonal prism lens shape in which the upper and lower bases of the hexagonal column are convex and the center is flat. That is, the end surface orthogonal to the central axis of the hexagonal column is formed as a bulging curved surface with a flat center. By forming the pre-forged billet 13c into a hexagonal prism lens shape, forging defects due to buckling can be prevented, and as a result, the yield can be improved. Moreover, the generation | occurrence | production of the wrinkle damage | wound by forging can be suppressed by giving roundness to the corner | angular of the pre forge billet 13c. It is preferable to apply a small R to the ridge line where the bulging surface and the hexagonal column side surface intersect. Furthermore, the thickness of the side surface of the hexagonal column portion is thin at the corner portion, and gradually increases between the corners. Thereby, when covering the hexagonal surface with the curvature radius of the curved surface being constant, it is possible to prevent a gap from being generated between the corners when the corner portions contact each other.

Next, as shown in FIG. 14C, the obtained pre-forged billet 13b is erected with the side face down. Then, the pre-forged billet 13b is pressure-compressed from a direction different from the axis, that is, the vertical direction, by closed forging using a hexagonal column lens-shaped die again to obtain a pre-forged billet 13c. At this time, since the pre-forged billet 13b has a hexagonal columnar lens shape, the pre-forged billet 13b can be easily positioned with one side face down. That is, it is easy to press and compress in a direction different from the direction in which the pressure is compressed.

Next, as shown in FIG. 14D, the obtained pre-forged billet 13c is erected with the side face down. Then, the pre-forged billet 13c is pressure-compressed from a direction different from the axis, that is, the vertical direction by closed forging using a truncated cone-shaped die to obtain a pre-forged billet 13d. The pre-forged billet 13d has a truncated cone shape in which the peripheral surface (side surface) is tapered.

Next, as shown in FIG. 14 (e), the obtained pre-forged billet 13d is inverted and placed on the lower mold 20 so that the bottom surface with the larger area faces down. At this time, the pre-forged billet 13d is locked to the middle of the inner peripheral surface of the lower mold 20. That is, an air gap is generated below the bottom surface. And it is set as the pre forge billet 13e by which the outer part was deform | transformed by press-compressing from the same direction as an axis | shaft by the closed forging using a truncated cone shape type | mold. The pre-forged billet 13e has a truncated cone shape whose peripheral surface (side surface) is tapered. In addition, generation | occurrence | production of the flaw at the time of forging is suppressed by eliminating the angle | corner of a taper surface.

Next, as shown in FIG. 14 (f), the obtained pre-forged billet 13e is pressure-compressed in the axial direction by flat-pressing closed forging to obtain a cylindrical forged billet 10b. Instead of the cylindrical forged billet 10b, the pre-forged billet 13e may be used as it is as the forged billet.

Thus, in the manufacture of the forged billet 10b according to the third embodiment, as described above, since it is obtained with a history of sequentially pressing and compressing in different directions, the crystal grains in the entire metal crystal particles of the forged billet 10b. The proportion of the tissue having a small diameter increases (see the principle of FIG. 13).
Further, the outer portion Q of the pre-forged billet 13d is deformed by compressing and compressing so that the pre-forged billet 13d has a truncated cone shape, and then inverting and compressing again. That is, the material flow of the outer portion Q can be positively performed. Thereby, even if the forged billet 10b to be obtained is duralumin, the crystal grain size of the central part and the crystal grain size of the other part are approximately the same, and it becomes possible to refine the crystal grain size uniformly throughout. . In addition, the fatigue strength test of the forge billet which passed through the pre forge billet was done, and when repeated tension compression was performed with the test frequency of 20 Hz, it did not reach a fracture | rupture in 1 * 10 < ⁷ > cycles.

[Fourth Embodiment]
In the forging billet according to the fourth embodiment, the step of compressing and compressing the cast billet in one direction and the step of compressing and compressing the cast billet in a direction different from the direction of pressing and compressing are performed in the same process using swing forging. This is different from the forged billet 10a according to the second embodiment in that it is performed. The wheel and the wheel manufacturing method are the same as described above.

FIG. 15 is a schematic view illustrating a manufacturing process of a forged billet according to the fourth embodiment.
As shown in FIG. 15, the forged billet 10 c according to the fourth embodiment is manufactured using swing forging. Note that swing forging is performed by pressure molding locally, and upsetting forging has an advantage that forging can be performed with a pressurizing force of 1/5 to 1/10 that of a general press.

In the swing forging, the upper die 41 to be pressed is a cylindrical body having a conical surface on the pressing surface. On the other hand, the lower mold 42 constitutes a bottomed hole 42a having a predetermined diameter. The casting billet 4 having a diameter smaller than the hole diameter is disposed in the hole portion 42a, the apex surface of the upper mold 41 is pressed against the center of the upper surface of the casting billet 4, and the drive shaft extends above the center of the upper mold 41. Applying pressure and causing precession. The swinging motion repeats the operation of sequentially pressing the conical surface of the upper mold 41 against the upper surface of the casting billet 4 while performing a circular motion. By this operation, the upper surface of the cast billet 4 is pushed out while being pressed in the direction in which the mold advances, and is also pushed out to the side surface side of the cast billet 4. By repeating this operation, the height of the cast billet is lowered and the diameter is increased. Become. Thus, the forged billet 10c is obtained by extruding the material of the cast billet 4 in different directions in the same process. At this time, the lower die 42 serves as closed forging. Further, the forging ratio of the forging billet is determined by appropriately setting the hole diameter of the lower die 42.

The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

For example, in the forged billet according to the first embodiment, the cast billet is manufactured by pressing and compressing in the axial direction, but the pressing and compressing is not limited to the axial direction. For example, the horizontal direction may be used. That is, H1 / H2 (forging ratio) indicates the length in the direction in which the cast billet is pressed (lateral direction), and H2 indicates the length in the direction in which the forged billet is pressed (lateral direction). It will be.

In the method for manufacturing the wheel 3 according to the present embodiment, the pre-disc portion 14, the pre-outer rim portion 7b, and the pre-inner rim portion 8b are formed by extrusion forging, which is forging, and then pre-formed by machining or the like. Although the disk part 14 is the disk part 6, the pre-outer rim part 7b is the outer rim part 7, and the pre-inner rim part 8b is the inner rim part 8, the disk part 6 and the outer rim part 7 are directly formed by extrusion forging. The inner rim portion 8 may be used.

In the manufacturing method of the wheel 3 according to the present embodiment, extrusion forging is performed as forging, but press working may be used.
FIG. 16 is a schematic view showing a manufacturing process from a forged billet to a wheel according to another embodiment.
As shown in FIG. 16, also in the manufacturing process from the forge billet to a wheel which concerns on other embodiment, a forge forming process, a heat treatment process, and a finishing process are provided. In addition, what is necessary is just to perform a heat treatment process and a finishing process similarly to the manufacturing method of the wheel 3 which concerns on this embodiment mentioned above.

The forging process includes a first press molding 21, a second press molding 22, and a third press molding 23.
Specific methods of the first press molding 21, the second press molding 22, and the third press molding 23 include free forging, die forging, swing forging, extrusion forging, rotary forging, and closed forging. Note that die forging includes press forging and hammer forging. Also, partial forging can be used in which the forging billet 10 is rotated by a certain angle and the operation of pressurizing a part thereof is repeated.
Among these, the first press molding 21, the second press molding 22, and the third press molding 23 are all preferably closed forging. In this case, it is possible to manufacture the wheel 3 having a more uniform mechanical strength.

The processing conditions at this time may be any of hot forging, warm forging, cold forging, and isothermal forging. These forging processes are preferably performed at a temperature of 300 ° C. or higher, preferably 300 to 550 ° C. and a pressure of 9.8 × 10 ³ kN to 88.2 × 10 ³ kN.

By performing the forging as described above, the forged billet 10 is forged and then cooled to obtain the prewheel 3a.
After the machining, the wheel is obtained by performing a heat treatment process of heat treatment and an aging treatment and a finishing process such as turning machining in the same manner as the wheel manufacturing method according to the present embodiment.

In addition, although the forge molding at the time of manufacturing a wheel is provided with three times of the 1st press molding 21, the 2nd press molding 22, and the 3rd press molding 23, even if the frequency | count of a forge molding is 1 time. It may be multiple times.

In the method for manufacturing the wheel 3 according to the present embodiment, a pre-wheel is illustrated as a semi-finished product, but the present invention is not limited to this, and includes an intermediate product. The wheel 3 is an example of a finished product.

In the wheel 3 according to this embodiment, the shape of the spoke portion 11 is Y-shaped, but is not limited thereto. It may be fan-shaped, X-shaped, or dish-shaped.

In the wheel, a pre-rim portion 5 standing on the periphery of the wheel 3 is provided and processed into an outer rim portion 7 and an inner rim portion 8. That is, in the wheel, a disc unit 6 and a pre-rim unit 5 integrated with each other are used, but a two-piece wheel or a three-piece wheel other than a one-piece wheel may be used.
In the case of a two-piece wheel or a three-piece wheel, the disk portion, the outer rim portion or the inner rim portion is individually forged using the forged billet 10 and integrated by a coupling means.
Examples of the coupling means include bolts and nuts, screwing, friction welding, rivet tightening, or hack bolts equipped with caulking members.

In the case of a two-piece wheel or a three-piece wheel, a forged billet 10 made of duralumin is used to forge the disk portion, outer rim portion or inner rim portion, and the other portions that are not forged are aluminum alloys other than duralumin. (For example, A6000 series) may be cast or forged, and these may be integrated by a coupling means.

In the case of a two-piece wheel or a three-piece wheel, for example, the pre-inner rim portion is manufactured separately, so that the pressure in the forging means can be reduced. In this case, since only the disk part or the disk part and the outer rim part are forged, the average height after forging becomes small. For this reason, there is also an advantage that the training ratio can be increased.

Specifically, the following production methods can be mentioned.
(A) A rim portion in which a disk portion is formed by itself using a forged billet 10 made of duralumin, and an outer rim portion and an inner rim portion are integrally formed using a forged billet 10 made of duralumin or a cast billet made of A6000 series. Are formed as a single body, and an annular mounting seat is provided on each of them, and they are coupled with a plurality of bolts and nuts.
(B) A disk part is formed by itself using a forged billet 10 made of duralumin, and an outer rim part and an inner rim part are formed by using a forged billet 10 made of duralumin or a cast billet made of A6000 series, and the same as above. Integrate in the same way.
(C) When making a disk portion using a forged billet 10 made of duralumin, an outer rim portion is formed integrally, and an inner rim portion is formed using a forged billet 10 made of duralumin or a cast billet made of A6000, Connect with multiple bolts and nuts.
(D) When a disk part is made using a forged billet 10 made of duralumin, an inner rim part is formed integrally, and an outer rim part is formed using a forged billet 10 made of duralumin or a cast billet made of A6000, Connect with multiple bolts and nuts.
(E) When making a disk part using the forge billet 10 which consists of duralumin, an outer rim part and an inner rim part are integrally molded as a pre-rim part.

In the forged billet according to the second embodiment, the cast billet is compressed and compressed into a hexagonal column-shaped pre-forged billet, and then compressed and compressed from the lateral direction to obtain the final hexagonal column-shaped forged billet. A cast billet that has been compressed into a hexagonal column may be used as the final forged billet.
Further, the forged billet and the pre-forged billet may have a polygonal column shape with many corners such as a hexagonal column shape, an octagonal column shape, or a dodecagon column shape.

In the forged billet according to the second embodiment, the cast billet is pressure-compressed to form a pre-forged billet, which is further compressed in a vertical direction different from the direction in which the pre-forged billet is compressed. The number of compressions is not limited to two, and may be performed three or more times.
Similarly, in the forged billet according to the third embodiment, the flat forged pre-forged billet is pressure-compressed twice from different vertical directions, but may be performed three or more times, and the hexagonal frustum-shaped pre-forged The billet may be inverted and compressed under pressure a plurality of times.
The hexagonal columnar pre-forged billet may be a polygonal columnar lens shape including a cylindrical lens shape, and the truncated cone-shaped pre-forged billet may be a polygonal frustum shape including a hexagonal frustum shape. Good. That is, the shape is not limited, and the cast billet is pressure-compressed in one direction to form a pre-forged billet, and further compressed and compressed in a direction different from the direction in which the pre-forged billet is compressed, and the outer portion is deformed. In order to achieve this, it may be obtained by further pressing and compressing.
Furthermore, when the cylindrical casting billet is pressed in one direction, the pressing surface is formed as a convex curved surface or a concave curved surface, and the material is moved from the center to the circumferential direction by repeating this alternately several times or circumferentially. The crystal grain size may be refined by moving from the center to the center.

Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to the following examples.

First, the physical properties of the wheel according to the present invention were investigated.
Example 1
Duralumin was prepared as a light metal alloy. This was melted to obtain a molten raw material. In an argon gas atmosphere, cast into a casting machine by a continuous casting method, heated, and then cooled to form a cylindrical cast billet (standard number: A2017 (A2000 series)) having a diameter of 204 mm, a height of 219 mm, and a weight of 20 kg. Obtained.

The obtained cast billet was subjected to pressure compression by the closed hexagonal forging process shown in FIG. That is, as shown in FIG. 14 (a), a cast billet is placed on a press machine, and 34.3 × 10 ³ kN under the temperature conditions of a mold temperature of 364 ° C. to 391 ° C. and a workpiece temperature of 459 ° C. to 485 ° C. The hot flat forging was performed with the pressure of.
Next, as shown in FIGS. 14B, 14 C, and 14 D, the workpiece was forged and formed into a hexagonal prism lens shape having bulges on the upper and lower surfaces. At this time, the mold temperature was 383 ° C. to 399 ° C., and the workpiece temperature was 417 ° C. to 464 ° C.
Further, as shown in FIGS. 14E and 14F, the workpiece was forged into a truncated cone shape, and the material of the outer portion of the workpiece was actively deformed to make the crystal grain size of the entire workpiece uniform. In this step, the mold temperature was 370 ° C. to 395 ° C., the workpiece temperature was 410 ° C. to 462 ° C., and the pressing force during this period was 39.2 × 10 ³ kN. By cooling with a fan, a cylindrical forged billet with a height of 54 mm was obtained. The forging ratio of the forged billet was 4.

Next, based on the method shown in FIGS. 5A and 5B, the die temperature 387 ° C. to 399 ° C., the workpiece temperature 422 ° C. to 498 ° C., and the applied pressure 49 × 10 ^{3 are} applied to the forged billet obtained. A forward extrusion forging process is performed under a temperature and pressure condition of kN. Further, in the steps shown in FIGS. 6 (a) and 6 (b), the workpiece is inverted and placed on the mold, and the mold temperature is 388 ° C. to 399 ° C. Back extrusion forging was performed under the conditions of ℃, workpiece temperature of 392 ° C to 470 ° C, and applied pressure of 78.4 x 10 ³ kN.
Further, based on the method shown in FIGS. 7A and 7B, flaring processing for expanding the inner rim end portion was performed. At this time, the mold temperature was 386 ° C. to 399 ° C., the workpiece temperature was 448 ° C. to 495 ° C., and the applied pressure was 2.94 × 10 ³ kN. Thus, the work was completed as a pre-wheel.

The resulting pre-wheel is heat-treated under T6 conditions, and a wheel having a shape shown in FIG. 9A (flange diameter 19 inches) is obtained by machining to remove a forging margin using a lathe or a milling machine including a machining center. It was.

(Example 2)
Instead of the aluminum alloy A2017 in Example 1, A2014 was used. The forging process of the forged billet was performed as follows with the same size of the cast billet. As shown in FIG. 14 (a), an A2014 cast billet was placed on a press machine, and under a temperature condition of a mold temperature of 351 ° C. to 382 ° C. and a workpiece temperature of 401 ° C. to 478 ° C., 19.6 × 10 ³ kN Hot flat forging was performed under pressure.
Next, as shown in FIGS. 14B, 14 C, and 14 D, the workpiece was forged and formed into a hexagonal prism lens shape having bulges on the upper and lower surfaces. At this time, the mold temperature was 351 ° C. to 399 ° C., the workpiece temperature was 407 ° C. to 473 ° C., and the applied pressure was 29.4 × 10 ³ kN. In Example 2, flat pressing forging was performed in a cylindrical shape in the step (d) of FIG. A forged billet was formed at a mold temperature of 358 ° C. to 398 ° C. and a pressing force of 29.4 × 10 ³ kN. The height was 54 mm. A forging process shown in FIG. 16 was used for forging the forged billet into the pre-wheel, and spinning was performed by the method shown in FIG. 8 to complete the wheel (flange diameter 19 inches).

(Example 3)
Instead of the aluminum alloy A2014 in Example 2, A7N01 (cast billet) was used. As shown in FIG. 14 (a), an A701 cast billet was placed on a press machine, and under a temperature condition of a mold temperature of 353 ° C. to 398 ° C. and a workpiece temperature of 404 ° C. to 444 ° C., 19.6 × 10 ³ kN. Hot flat forging was performed under pressure.
Next, as shown in FIGS. 14B, 14 C, and 14 D, the workpiece was forged and formed into a hexagonal prism lens shape having bulges on the upper and lower surfaces. At this time, the mold temperature was 351 ° C. to 391 ° C., the workpiece temperature was 402 ° C. to 451 ° C., and the applied pressure was 29.4 × 10 ³ kN. In Example 3, flat pressing forging was performed in a cylindrical shape in the step (d) of FIG. A forged billet was formed at a mold temperature of 354 ° C. to 389 ° C., a workpiece temperature of 407 ° C. to 439 ° C., and a pressing force of 29.4 × 10 ³ kN. The height was 54 mm. The process of forging a forged billet into a pre-wheel and the spinning process were performed in the same manner as in Example 2 to complete the wheel (flange diameter 19 inches).

(Comparative Example 1)
A wheel was obtained in the same manner as in Example 1 except that a cast billet of A6151 (A6000 series) was used instead of using the forged billet of A2017.

[Evaluation 1]
Tensile strength was measured according to JIS-Z2241 for the spoke, inner rim, inner flange, outer flange, and hub portions of the wheels obtained in Examples 1 to 3 and Comparative Example 1. The obtained values are shown in Table 1.

[Evaluation 2]
The 0.2% proof stress was measured according to JIS-Z2241 for the spoke part, inner rim part, inner flange part, outer flange part, and hub part of the wheel obtained in Examples 1 to 3 and Comparative Example 1. . The obtained values are shown in Table 1.

[Evaluation 3]
Elongation was measured according to JIS-Z2241 for the spoke part, inner rim part, inner flange part, outer flange part, and hub part of the wheels obtained in Examples 1 to 3 and Comparative Example 1. The obtained values are shown in Table 1.

Brinell hardness was measured according to JIS-Z2243 for the spoke part, inner rim part, inner flange part, outer flange part and hub part of the wheel obtained in Examples 1 to 3 and Comparative Example 1. The obtained values are shown in Table 1.

[Evaluation 5]
Charpy impact values were measured in accordance with JIS-Z2242 for the spoke, inner rim, inner flange, outer flange, and hub portions of the wheels obtained in Examples 1 to 3 and Comparative Example 1. The obtained values are shown in Table 1. In Table 1, “-” means not measured.

[Table 1]

From the results shown in Table 1, the wheels obtained in Examples 1 to 3 were extremely superior in overall tensile strength and Charpy impact value as compared with the wheel obtained in Comparative Example 1. Therefore, it was confirmed that the wheel of the present invention has excellent mechanical strength and can be reduced in weight.

Next, the relationship between the physical properties of the forged billet and the forging ratio was investigated.
Example 4
Duralumin was prepared as a light metal alloy. This was melted to obtain a molten raw material. In an argon gas atmosphere, the casting was poured into a casting machine by a continuous casting method, heated, and then cooled to obtain a casting billet (standard number: A2017 (A2000 series)). For the obtained billet (height 232.8 mm), the forging ratio was obtained by closed forging under the temperature conditions of the heating furnace set temperature of 525 ° C, the mold temperature of 380 ° C to 400 ° C, and the workpiece temperature of 480 ° C to 510 ° C. Was compressed so as to be 2 to obtain a cylindrical forged billet having a diameter of 52.1 mm and a height of 116.4 mm.

(Example 5)
A forged billet was obtained in the same manner as in Example 4 except that a cast billet having a height of 349.2 mm was used and pressure compression was performed so that the forging ratio was 3. In addition, the size of the obtained forge billet is diameter 52.1mm and height 116.4mm.

(Example 6)
A forged billet was obtained in the same manner as in Example 4 except that a cast billet having a height of 465.6 mm was used and pressure compression was performed so that the forging ratio was 4. In addition, the size of the obtained forge billet is diameter 52.1mm and height 116.4mm.

(Example 7)
A forged billet was obtained in the same manner as in Example 4 except that a cast billet having a height of 582 mm was used and pressure compression was performed so that the forging ratio was 5. In addition, the size of the obtained forge billet is diameter 52.1mm and height 116.4mm.

(Example 8)
A forged billet was obtained in the same manner as in Example 4 except that a cast billet having a height of 698.4 mm was used and pressure compression was performed so that the forging ratio was 6. In addition, the size of the obtained forge billet is diameter 52.1mm and height 116.4mm.

Example 9
A forged billet was obtained in the same manner as in Example 4 except that a cast billet having a height of 814.8 mm was used and pressure compression was performed so that the forging ratio was 7. In addition, the size of the obtained forge billet is diameter 52.1mm and height 116.4mm.

(Example 10)
A forged billet was obtained in the same manner as in Example 4 except that a cast billet having a height of 931.2 mm was used and pressure compression was performed so that the forging ratio was 8. In addition, the size of the obtained forge billet is diameter 52.1mm and height 116.4mm.

(Example 11)
A forged billet was obtained in the same manner as in Example 4 except that a cast billet having a height of 1047.6 mm was used and pressure compression was performed so that the forging ratio was 9. In addition, the size of the obtained forge billet is diameter 52.1mm and height 116.4mm.

(Example 12)
A forged billet was obtained in the same manner as in Example 4 except that a cast billet having a height of 1164 mm was used and pressure compression was performed so that the forging ratio was 10. In addition, the size of the obtained forge billet is diameter 52.1mm and height 116.4mm.

(Comparative Example 2)
The cylindrical cast billet obtained in Example 4 was used as it was. The obtained cast billet has a diameter of 52.1 mm and a height of 116.4 mm.

[Evaluation 6]
The tensile strength of the forged billet obtained in Examples 4 to 12 and the cast billet obtained in Comparative Example 2 was measured according to JIS-Z2241. The obtained results are shown in Table 2.

[Evaluation 7]
The 0.2% yield strength of the forged billet obtained in Examples 4 to 12 and the cast billet obtained in Comparative Example 2 was measured according to JIS-Z2241. The obtained values are shown in Table 2.

[Evaluation 8]
For the forged billets obtained in Examples 4 to 12 and the cast billet obtained in Comparative Example 2, the elongation was measured according to JIS-Z2241. The obtained values are shown in Table 2.

[Evaluation 9]
Brinell hardness was measured according to JIS-Z2243 for the forged billets obtained in Examples 4 to 12 and the cast billet obtained in Comparative Example 2. The obtained values are shown in Table 2.

[Evaluation 10]
Charpy impact values of the forged billets obtained in Examples 4 to 12 and the cast billet obtained in Comparative Example 2 were measured according to JIS-Z2242. The obtained values are shown in Table 2.

[Table 2]

From the results in Table 2, it was found that the Charpy impact value became extremely large as the training ratio was increased.
In particular, when the forging ratio was 4 or more, the Charpy impact value was 30 J / cm ² or more, and it was confirmed that sufficient mechanical strength could be exhibited.

According to the forged billet of the present invention, a wheel having excellent mechanical strength and uniform mechanical strength can be produced. The obtained wheel is suitably used for applications such as vehicles and aircraft wheels. In particular, when it is used for a vehicle, the weight of the automobile can be reduced, so that the environmental load caused by gasoline or the like can be reduced, and the cost can be reduced. More importantly, the forged wheel using the forged billet of the present invention has a very high Charpy impact value and elongation when a crack occurs in the rim or disc part for some reason during traveling in a vehicle or the like. Therefore, it is possible to provide a safer wheel that does not lead to a major accident because, for example, the tire pressure gradually decreases and the operator notices abnormalities.

DESCRIPTION OF SYMBOLS 1 ... Main-body part 3 ... Wheel 3a ... Prewheel 3b ... 1st prewheel (prewheel)
3c ... 2nd pre-wheel (pre-wheel)
3d ... Third pre-wheel (pre-wheel)
4 ... cast billet 5 ... pre-rim part 6 ... disk part 6a ... hub part 6b ... bolt insertion hole 7 ... outer rim part 7a ... outer flange part 7b ... pre Outer rim part 8 ... Inner rim part 8a ... Inner flange part 8b ... Pre-inner rim part 9 ...

Empty part

10, 10a, 10b, 10c ... Forged billet 11 ... Spoke

part

12 , 12a, 12b, 12c, 13a, 13b, 13c, 13d, 13e ... Pre-forged billet 14 ...

Pre-disc portion

13a, 13b, 13c, 13d, 13e ...

Pre-forged billet

16, 18, 25, 41 ...

Upper mold

17, 19, 20, 26, 42 ...

Lower mold

17a, 19a, 26a ... Knockout part 21 ... First press molding 22 ... 2 press molding 23 ... 3rd press molding 31 ... 1st spinning device 31a ... inner side die 31b ... outer side die 35 ... rolling roller 32 ... 2nd spinning device 32a ... -Inner mold 32b ...

Outer mold

38a, 38b ... Gap 42a ...

Hole

51, 52, 53, 54 ...

Mold

51a, 52a, 53a, 54a ... Cylindrical hole A ... Fine area B ... NG area H1, H2, H3 ... Height P ... Restraint force P1, P2 ... Direction Q ... Outer part

Claims

A forged billet obtained by casting a light metal alloy to form a cast billet, pressurizing and compressing the cast billet to refine the metal structure of the cast billet,
A forged billet in which the light metal alloy is duralumin.
The forged billet according to claim 1, wherein 50-80% of the total volume of grain boundary precipitates is refined by the pressure compression, and stress corrosion cracking is suppressed.
The forged billet according to claim 1 or 2, wherein the tensile strength measured according to JIS-Z2241 is 400 MPa or more.
The forged billet according to any one of claims 1 to 3, wherein the 0.2% proof stress measured according to JIS-Z2241 is 300 MPa or more.
Elongation measured according to JIS-Z2241 is 20% or more,
The forged billet according to any one of claims 1 to 4, wherein the Charpy impact value measured according to JIS-Z2242 is 30 J / cm 2 or more.
A method for producing a forged billet according to any one of claims 1 to 5,
A method for producing a forged billet satisfying the following formula.
H1 / H2 ≧ 4.0
(In the formula, H1 indicates the length in the direction in which the cast billet is compressed and compressed, and H2 indicates the length in the direction in which the forged billet is compressed and compressed.)
The method for producing a forged billet according to claim 6, wherein the pressure compression is performed by closed forging, swing forging, hammer forging, section forging or free forging. *
The forged billet according to claim 6 or 7, wherein the cast billet is pressure-compressed in one direction to obtain a pre-forged billet, and further compressed and compressed in a direction different from the direction in which the pre-forged billet is compressed. Manufacturing method.
The cast billet is pressure-compressed in one direction to form a pre-forged billet, further compressed in a direction different from the direction in which the pre-forged billet is compressed, and further compressed to compress the outer portion. A method for producing a forged billet according to claim 6 or 7 obtained by the method described above.
The cast billet is pressure-compressed in one direction to form a pre-forged billet, further compressed and compressed in a direction different from the direction in which the pre-forged billet is compressed and compressed into a truncated cone shape, and the outer portion is deformed. The manufacturing method of the forge billet of Claim 6 or 7 compressed and compressed for this purpose.
The forging billet according to claim 8, wherein the step of compressing and compressing the cast billet in one direction and the step of compressing and compressing in a direction different from the direction of pressurizing and compressing are performed in the same step using swing forging. Production method.
The forged billet according to any one of claims 6 to 11, wherein the forged billet is for flying parts, for transportation equipment parts, for industrial equipment parts, for building materials, for optical equipment parts, or for manufacturing a member for these uses. Manufacturing method.
A finished product or semi-finished product obtained by molding the forged billet according to any one of claims 1 to 5.
A finished product or semi-finished product obtained by molding a forged billet obtained by the method for producing a forged billet according to any one of claims 6 to 12.
A method for producing a wheel using a forged billet obtained by the method for producing a forged billet according to any one of claims 6 to 11,
A manufacturing method of a wheel in which a Charpy impact value of a disk portion, an outer flange portion, an inner rim portion, and an inner flange portion comprising a hub portion and a spoke portion is 30 J / cm 2 or more.
When the wheel and the A6000 series wheel made of an A6000 series aluminum alloy have the same mechanical strength, the wheel is at least 10% lighter than the A6000 series wheel made of an A6000 series aluminum alloy. 15. The method for producing a wheel according to 15.
The average thickness of the well portion and the inner rim portion is 1.8 to 2.5 mm,
The average thickness of the hub portion is 35 to 66 mm,
When the wheel and the A6000 series wheel made of an A6000 series aluminum alloy have the same mechanical strength, the wheel is at least 15% lighter than the A6000 series wheel made of an A6000 series aluminum alloy. 15. The method for producing a wheel according to 15.
A pre-disc portion, a pre-outer rim portion and a pre-inner rim portion are formed on the forged billet by extrusion forging, and then the pre-disc portion is used as the disc portion, and the pre-outer rim portion is the outer rim portion. The wheel manufacturing method according to any one of claims 15 to 17, wherein the pre-inner rim portion is the inner rim portion.
The outer rim portion and the inner rim portion are formed by machining for removing a forging margin by a milling machine including a lathe or a machining center after forging the forged billet. Wheel manufacturing method.
The forging billet is forged into a semi-finished product, and most of the steps for forming a wheel shape are a lathe, a milling machine including a machining center, or a boring machining. The method for manufacturing a wheel according to one item.
Forming the inner rim part by spinning process in which a pre-rim part is formed by extrusion forging process on the forged billet and pressed with a rolling roller from an oblique direction in a state where a gap is provided between the pre-rim part and the mold. The method for manufacturing a wheel according to any one of claims 15 to 17.
The wheel manufacturing according to any one of claims 15 to 17, wherein the disk part, the outer rim part or the inner rim part is individually forged using the forged billet and integrated by a connecting means. Method.
The disc part, the outer rim part or the inner rim part is forged using the forged billet, and other parts not forged are cast or forged with an aluminum alloy other than duralumin, and these are integrated by a coupling means. The method for manufacturing a wheel according to any one of claims 15 to 17, wherein