JP3435906B2 - Manufacturing method of forged products - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a forged product used for forming a forging material by casting and then forging the forging material into a forged product having a desired shape. .

[0002]

2. Description of the Related Art Conventionally, as a method for manufacturing a forged product of this type, there is, for example, the one described in Japanese Patent Laid-Open No. 143201/1993.

This method of manufacturing a forged product is intended for a road wheel disc. First, a forging disc material having a shape similar to the shape of the disc portion of the road wheel disc is formed by casting. After that, the forging disc material is then formed into a desired disc portion shape by forging.

According to this manufacturing method, after forging a disk material having a shape similar to the shape of the disk portion of the road wheel disk by casting, the forging is performed into the desired disk shape. The advantage is that the forging process is simplified.

[0005]

However, in the above-mentioned conventional method for manufacturing a forged product (road wheel disc), the shape of the forging disc material formed by casting is the desired disc portion shape. Since they are similar, the degree of workability during forging is small, and therefore the effects of forging, such as the effect of fine fragmentation of resinous crystals generated during solidification in casting and the occurrence of grain flows It is hard to get the effects,
One of the characteristics of forged products is that it is difficult to obtain a smooth and glossy surface, and there has been a problem to overcome such difficulties.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above conventional problems, and after forming a forging material by casting, the forging material is formed into a forged product having a desired shape by forging. In this case, it is possible to further improve the mechanical properties by sufficiently obtaining the effects of forging (such as the effect of finely dividing resinous crystals and the effect of the generation of grain flows), and at the same time, smooth It is an object of the present invention to provide a method for manufacturing a forged product, which is capable of achieving a further improvement in surface quality by obtaining a glossy surface.

[0007]

A method for manufacturing a forged product according to the present invention is a method of casting as described in claim 1 .
After forging the forging material, forge the forging material
When forming a forged product with a more desired shape, the forging material
The reduction ratio of the part of the material that is thinned by forging is 1
5% or more, forward extrusion during forging, backward
Formed by plastic flow by extrusion or upset processing
It is characterized in that the stress of the part to be exposed is 50 MPa or more .

Further, in an embodiment of the method for manufacturing a forged product according to the present invention, as described in claim 2, the forging material is a portion whose wall thickness is reduced by forging.
The rolling reduction of 15% or more and before the forging
Plastic by side extrusion, backward extrusion or upset processing
The stress of the part formed by flowing becomes 50 MPa or more
As such, it can be formed by casting .

Also, the manufacture of a forged product according to the present invention
In an embodiment of the method, in particular according to claim 3.
As shown in the figure, the forged product is a disk for a road wheel, and the bottom wall portion of the recess corresponding to the portion where the wall thickness is thinned by forging in the spoke portion where the recess and protrusion are formed has a rolling reduction of 15% or more. And push forward by forging
The projecting portion of the convex portion corresponding to the portion formed by plastic flow by extrusion, backward extrusion or upset processing has a stress of 50M.
Pa or more can be obtained, and in this case, as described in claim 4 , the outer rim can be formed integrally with the disc.

Furthermore, in an embodiment of the method for producing a forged product according to the present invention, as described in claim 5 , the strain amount is 0.25 or more (elongation is 25% instead of 15% or more in the rolling reduction. The above can be obtained.

[0011]

According to the method for manufacturing a forged product according to the present invention, as described in claim 1, a forging material is produced by casting.
After forming, forging the material for forging into a desired shape
When forming into a forged product, forging among the forging materials
The thickness reduction is 15% or more.
Together with the forward extrusion, backward extrusion or
Stress in the part formed by plastic flow due to the plc set process
Is set to 50 MPa or more, but in this case, the reduction ratio of 15% or more and the stress of 50 MPa or more are obtained for the following reason.

That is, the relationship between the rolling reduction and the yield strength and the tensile strength at the time of forging of the forging material formed by casting was examined, and the relations between the rolling reduction and the elongation were examined. The exemplified results were obtained (however, each shows the case where T6 treatment was carried out after forging. Further, a reduction rate of 0% indicates that it was as-cast.) As shown in FIG. In relation to tensile strength, the yield strength is about 2 by setting the rolling reduction to 15% or more.
It is possible to obtain not less than 20 MPa and a tensile strength of about 300 MPa or more.
As shown in, in the relationship between the rolling reduction and the elongation, the rolling reduction is 1
By setting it to 5% or more, it was possible to obtain elongation of about 14% or more.

[0013] In addition, in after performing the forging to the forging material that was molded by casting, was examined the relationship between the main stress and the mechanical properties of forgings is received, the time of forging
Front extrusion, rear extrusion or upset processing
It was found that by setting the stress of the portion formed by plastic flow to 50 MPa or more, good mechanical properties such as a yield strength of 220 MPa or more, a tensile strength of 300 MPa or more, and an elongation of 14% or more can be obtained.

Therefore, in the present invention, forging is performed by casting.
After molding the material for the forging, the forging material is forged
When forming into a desired shape of forged product,
Then, the reduction rate of the part where the wall thickness is reduced by forging is 15% or less.
In addition to the above, forward extrusion and backward extrusion during forging
Or a part formed by plastic flow by upset processing
Since the stress for each part is set to 50 MPa or more, the strength effect of forging in each part of the forged product (the effect of fine fragmentation of the resin-like crystals and the effect of the generation of grain flow lines) is sufficient. In addition to providing further improvement in mechanical properties,
Due to the effect of strong pressurization by forging, a smooth and glossy surface is obtained, so that the surface quality is further improved.

Then, as described in claim 2,
The forging material is pressed against the part where the wall thickness is reduced by forging.
The lowering ratio should be 15% or more, and the forward pushing at the time of forging
Plastic flow due to extrusion, backward extrusion or upset processing
So that the stress of the formed part becomes 50 MPa or more
In addition, by forming by casting , the effect on strength by forging is sufficiently obtained, further improving the mechanical properties is brought about, and the effect of strong pressurizing by forging is sufficiently obtained, resulting in smoothness. Obtaining a glossy surface will lead to a further improvement in surface quality.

Further, as described in claim 1 or 2 , the portion of the forging material whose wall thickness is thinned by forging has a reduction ratio of 15% or more and is forward extruded during forging.
By making the portion formed by plastic flow by backward extrusion or upset processing obtain a stress of 50 MPa or more, the portion of the forging material where the wall thickness becomes thin can be expressed by the reduction rate (that is, the reduction rate). Rate = [(H−h) / H] × 100 (%)
H is the thickness or height before forging, and h is the thickness or height after forging. ), Such a portion where the wall thickness becomes thin is designed to obtain a reduction rate of 15% or more, and a portion formed by plastic flow by forward extrusion, backward extrusion or upset processing during forging is expressed by the above reduction rate. Since it cannot be done, the portion formed by such plastic flow is expressed by internal compressive stress.
It was decided to perform forging so as to receive Pa or more.

By obtaining such a rolling reduction of 15% or more and / or a stress of 50 MPa or more, the strength effect by forging becomes sufficient, whereby the mechanical properties are further improved, and the forging is performed. The effect of strong pressurization by means of being sufficient to obtain a smooth and glossy surface will further improve the surface quality.

Further, as described in claim 3 ,
When the forged product is a road wheel disc, the bottom wall portion of the recess corresponding to the portion of the road wheel disc where the recess and the protrusion are formed is thinned by forging, and the reduction ratio is 15 % Or more, and forward extrusion, backward extrusion or forging
Is a high-performance road wheel excellent in both mechanical properties and surface quality by making the protruding part of the convex part corresponding to the part formed by plastic flow by upset processing obtain a stress of 50 MPa or more. As a result, a disc for use in the road wheel is obtained, and by forming the outer rim integrally with the disc as described in claim 4 , the outermost of which is the most required strength and the appearance of the wheel in the road wheel. The rim also has an effect of improving strength and surface quality by forging.

[0019] Furthermore, as a result of examining the relationship between the amount of strain at a reduction ratio and forgings for the forging material which is molded by casting, since it is proportional as shown in FIG. 14 was observed, claim As described in 5 ,
Even when the strain amount is 0.25 or more (elongation is 25% or more) instead of the rolling ratio of 15% or more, similarly, a high quality forged product excellent in both mechanical properties and surface quality or A disk for a road wheel and other mechanical elements can be obtained.

[0020]

EXAMPLE 1 FIGS. 1 to 6 show an example of a method for manufacturing a forged product according to the present invention, in which the forged product is a disk for a road wheel. 1 shows a disk material 1 as a forging material formed by casting, and FIG. 2 shows a disk 2 as a forged product formed by forging the disk material 1 into a desired shape.

The disc material 1 shown in FIG.
It is made of an aluminum alloy capable of achieving both good castability and forgeability as well as good mechanical properties by appropriately adjusting the i content and the like,
Spokes having a recessed hub mounting portion equivalent portion 1A in the central portion on the back side (lower side in FIG. 1) and having a concave portion 1B and a convex portion 1C formed on the outer peripheral side of the hub mounting portion equivalent portion 1A. It has an equivalent portion 1D, and further has an annular inner rim joint portion equivalent portion 1E projecting to the back side on the outer circumference of the spoke portion equivalent portion 1D, and an outer rim equivalent portion 1E on the outer periphery of the inner rim joint portion equivalent portion 1E. 1F, and is formed into a shape that can ensure a desired degree of processing for the disk 2 that is a forged product having a desired shape as a whole.
A center hole 1G is provided in the center of the hub mounting portion 1A so that a material flow can be generated during forging.

When setting the shape of the disk material 1, the disk 2 having the desired shape is forged.
If the reduction ratio of the part where the wall thickness becomes thin is 15% or more,
In the case of forging, front extrusion, rear extrusion or upsizing
The stress of the part formed by plastic flow due to
It is set to 0 MPa or more .

After forging, as shown in FIG. 2, a hub mounting portion 2A having a recessed shape is formed in the central portion on the back side (lower side of FIG. 2) as a portion corresponding to the disc material 1. At the same time, the hub mounting portion 2A has a spoke portion 2D formed with a concave portion 2B and a convex portion 2C on the outer peripheral side thereof, and further has an annular inner rim joint portion 2E projecting to the rear side on the outer periphery of the spoke portion 2D, The disc 2 having the outer rim 2F on the outer circumference of the inner rim joint 2E is formed.

Therefore, when the disc material 1 shown in FIG. 1 to the disc 2 shown in FIG. 2 are formed by forging, the thickness t ₁ of the hub attachment portion 1A of the disc material 1 is
And the thickness t ₂ at the hub mounting portion 2A of the disk 2 is such that in the forging from the thickness t ₁ to the thickness t ₂ , a reduction ratio of 15% or more can be obtained in this embodiment. The thickness t ₁ is 1.3 times or more the thickness t ₂ (that is, a reduction rate of about 23% or more), and the thickness t ₃ at the bottom portion of the recess 1B of the disk material 1 and the recess 2 of the disk 2 are set.
Relationship between the thickness t ₄ of the bottom wall portion of the B, as can be obtained above rolling reduction of 15% in the forging of a thickness of t ₃ to the thickness t _4, the thickness t ₃ in this embodiment The thickness t ₄ is set to 1.3 times or more (that is, the rolling reduction is about 23% or more).

Further, the height h of the convex portion 1C of the disk material 1
₁ (see FIG. 4) increases to the height h ₂ (see FIG. 5) of the convex portion 2C of the disk 2 due to the backward extrusion that occurs during forging, but the convex portion 2C is formed by the plastic flow of the material due to such backward extrusion. Since it cannot be evaluated by the rolling reduction when it is formed, the height of the convex portion 1C of the disk material 1 is set in this embodiment so that the convex portion 2C can be subjected to stress of 50 MPa or more by forging. It is assumed that h ₁ (see FIG. 4) is 1/3 or less of the height h ₂ (see FIG. 5) of the convex portion 2C of the disk 2.

Further, in the inner rim joint portion 2E of the disc 2, a material flow is generated from both sides with respect to the protruding portion of the inner rim joint portion 1E of the disc material 1 during forging, which causes Since a forging defect D such as a crack may occur as shown in FIG. 6, the volume is set to the same material distribution as that after forging. In addition, disk 2
In the outer rim 2F, since a part of the material flows to the outside of the forging die to form the flash 2H, it is possible to set dimensions with a margin.

As described above, after the disk material 1 having the thicknesses t ₁ , t ₃ and the height h ₁ etc. is formed by casting, the disk material 1 is forged into the disk 2 to reduce the rolling The thicknesses t ₂ and t _{4 at} which the rate of about 23% or more is obtained are forged, and at the same time, the height h ₂ that receives stress of 50 MPa or more is formed by backward extrusion as shown in FIG. The effect and the effect of improving the surface quality by the strong pressurization were brought about, and it was possible to manufacture the disk 2 for the load hole with good quality.

Further, the disk 2 in this embodiment is
The outer rim 2F is integrally formed, and by making it possible to obtain at least one of a reduction rate of 15% or more and a stress of 50 MPa or more at the time of forging in the portion of the outer rim 2F as well, It was possible to obtain sufficient mechanical strength and good surface quality by forging even in the outer rim 2F that requires the highest strength and has the appearance of a wheel.

Embodiment 2 FIGS. 7 to 10 show another embodiment of a method for manufacturing a forged product according to the present invention, which is for manufacturing a transburring for an automobile suspension which is a forged product having an H-shaped cross section. FIG. 7 shows a case where it is applied, and FIG. 7 shows a link material 11 as a forging material formed by casting, and FIG. 9 shows a forging product formed by forging the link material 11 into a desired shape. Trans bar link 12
Is shown.

Similar to the first embodiment, the link material 11 shown in FIG. 7 achieves both good castability and forgeability and good mechanical properties by appropriately adjusting, for example, the Si content. Which is made of an aluminum alloy capable of
A recessed portion 11B and a raised portion 11C are formed between 3 to form a substantially H shape as shown in FIG. 8, and the desired processing is performed on the transbar link 12 shown in FIGS. 9 and 10 which is the final shape as a whole. Link material with a shape that can secure the degree 11
Has become.

When specifically setting the shape of the link material 11, the transbar link 1 having a desired shape is used.
Of the two, the reduction ratio of the part where the wall thickness is thinned by forging
15% or more, forward extrusion during forging, rear
Formed by plastic flow by side extrusion or upset processing
The stress of the affected portion is set to 50 MPa or more .

Therefore, the thickness t ₅ of the recess 11B of the link material 11 and the thickness t ₅ of the recess 12B of the link 12 are set.
Relationship with _6, such that it is possible to obtain a higher reduction rate of 15% in the forging of the thickness t ₆ thick t _5, in the second embodiment, the first thickness t ₅ the thickness t _6. 4 times or more (that is, reduction rate of about 29% or more) and link material 1
The height h ₃ of the concave portion 11C in 1 increases to the height h ₄ of the convex portion 12C in the link 12 due to the extrusion that occurs during forging, but in the case of such extrusion, the reduction ratio cannot be evaluated, so In this embodiment, in order to be able to receive stress of 50 MPa or more in the convex portion 12C by forging, the convex portion 11 of the link material 11 is used in this embodiment.
The height h _{3 of} C is 2 of the height h ₄ of the protrusion 12C of the link 12.
It was reduced to less than one-third.

As described above, after the link material 11 having the thickness t ₅ and the height h ₃ etc. is formed by casting, the link material 11 is forged into the link 12 to reduce the rolling reduction by about 29%. The above is obtained by forging to a thickness t ₆ and a stress of 50 MPa due to extrusion.
It was possible to manufacture the transbar link 12 of high quality by being formed into the height h ₄ which is subjected to the above, and brought about the effect of improving the strength by forging and the effect of improving the surface quality by the strong pressurization.

Embodiment 3 FIG. 11 shows still another embodiment of the method for manufacturing a forged product according to the present invention, in which the arm portion 22A has a rectangular cross section and the bulging portions 22B are provided at both ends. It shows a case where it is applied to manufacture of the suspension upper arm 22, and the forging arm material formed by casting is not shown.

Also in this upper arm material, as in the above-mentioned embodiment, for example, the castability and the forgeability can be made compatible and good mechanical properties can be obtained by appropriately adjusting the Si content and the like. It is made of the aluminum alloy as a raw material.

When setting the shape of the arm material, when the plate thickness of the arm portion 22A of the upper arm 22 forged into a desired shape is t ₇ ,
The plate thickness of the arm portion of the arm material is 1.3 times or more of the plate thickness t ₇ (that is, the rolling reduction of about 23% or more) so that the rolling reduction of 15% or more can be obtained in the arm portion 22A by forging. In addition, the plate thickness of both end portions of the arm material is equal to or rather small than the plate thickness of the arm portion so that the bulging portion 22B can be subjected to stress of 50 MPa or more by forging.

In this way, after the arm material having the thickness of the arm portion and the thickness of both end portions set is formed by casting, the arm material is forged into the upper arm 22 so that the arm portion 22A is pressed down. Rate about 2
While being forged to a thickness t _{7 at} which 3% or more is obtained,
Both ends are formed into a bulging portion that receives a stress of 50 MPa or more due to plastic working, and is formed into a mounting portion 22B to a vehicle body or suspension member, which brings about an effect of strength improvement by forging and an effect of surface quality improvement by strong pressure. It was possible to manufacture a high quality upper link 22.

[0038]

According to the method for manufacturing a forged product according to the present invention, as described in claim 1, forging is performed by casting.
After molding the material, the forging material is desired by forging
When forming into a shaped forged product,
Then, the reduction rate of the part where the wall thickness is reduced by forging is 15% or less.
In addition to the above, forward extrusion and backward extrusion during forging
Or a part formed by plastic flow by upset processing
Since the stress for each part is set to 50 MPa or more, it is possible to sufficiently obtain the strength effect by forging in each part of the forged product (the effect of fine fragmentation of the resinous crystal, the effect of generation of grain flow lines, etc.). It is possible to further improve the mechanical properties, and it is possible to further improve the surface quality by obtaining a smooth and glossy surface due to the effect of strong pressure by forging. There is a remarkably excellent effect.

Then, as described in claim 2,
The forging material is pressed against the part where the wall thickness is reduced by forging.
The lowering ratio should be 15% or more, and the forward pushing at the time of forging
Plastic flow due to extrusion, backward extrusion or upset processing
So that the stress of the formed part becomes 50 MPa or more
In addition, by forming by casting, it is possible to achieve further improvement of mechanical properties by sufficiently obtaining the effect on strength by forging, and at the same time obtaining the effect of strong pressurization by forging. As a result, a smooth and glossy surface is obtained, so that the excellent effect that the surface quality can be further improved is brought about.

Further, as described in claim 1 or 2 , the portion of the forging material whose wall thickness is reduced by forging has a reduction ratio of 15% or more and is forward extruded during forging.
By forming the portion formed by plastic flow by backward extrusion or upset processing to have a stress of 50 MPa or more, the strength effect by forging becomes sufficient at each part of the forged product, so that the mechanical properties Excellent effect that further improvement is possible, and that the effect of strong pressurization by forging is sufficient to obtain a smooth and glossy surface and further improvement of surface quality is possible. Is brought about.

Further, as described in claim 3 ,
When the forged product is a road wheel disc, the bottom wall portion of the recess corresponding to the portion of the road wheel disc where the recess and the protrusion are formed is thinned by forging, and the reduction ratio is 15 % Or more, and forward extrusion, backward extrusion or forging
Is a high-performance road wheel excellent in both mechanical properties and surface quality by making the protruding part of the convex part corresponding to the part formed by plastic flow by upset processing obtain a stress of 50 MPa or more. It is possible to manufacture a disc for a vehicle, and by forming the outer rim integrally with the disc as described in claim 4 , the strength is required most in the road wheel and the appearance of the wheel is improved. The outer rim also has the excellent effect that the strength and surface quality can be improved by forging.

Further, as described in claim 5 , instead of reducing the rolling reduction of 15% or more, a strain amount of 0.25 or more (elongation of 25% or more) is obtained.
Similarly, it is possible to produce a high quality forged product excellent in both mechanical properties and surface quality, a disk for a road wheel, and other mechanical elements, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a diametrical cross-sectional explanatory view of a forging material before forging according to an embodiment of the present invention.

FIG. 2 is a cross-sectional explanatory view in the diametrical direction (line II-II of FIG. 3) of a disk (forged product) after forging according to an embodiment of the present invention.

FIG. 3 is a partial front explanatory view of a disk (forged product) after forging according to an embodiment of the present invention.

FIG. 4 is a partial cross-sectional explanatory view taken along the line IV-IV of FIG.

5 is a partial cross-sectional explanatory view taken along the line VV of FIG.

FIG. 6 is a cross-sectional explanatory view of a casting defect generation portion in the inner rim joint portion.

FIG. 7 is a front explanatory view of a forging material before forging according to another embodiment of the present invention.

8 is a cross-sectional explanatory view taken along the line VIII-VIII of FIG.

FIG. 9 is a front view showing a transbar link (forged product) according to another embodiment of the present invention.

10 is a cross-sectional explanatory view taken along line XX of FIG.

FIG. 11 is a perspective view of an upper link (forged product) according to still another embodiment of the present invention.

FIG. 12 is a graph showing an example of the results of examining the relationship between proof stress, tensile strength, and rolling reduction.

FIG. 13 is a graph showing an example of the result of examining the relationship between elongation and rolling reduction.

FIG. 14 is a graph showing an example of a result of examining a relationship between a strain amount and a rolling reduction.

[Explanation of symbols]

1 Disc material (forging material) 1A disk material equivalent to hub mounting part 1B disc material recess Convex part of 1C disk material Equivalent to the spoke part of 1D disc material 1E Disc material equivalent to inner rim joint Outer rim equivalent part of 1F disc material 2 discs (forged) 2A disc hub attachment 2B disc recess 2C disk protrusion 2D disc spokes 2E disc inner rim joint 2F disc outer rim 11 Link material (material for forging) 11B Link material recess Convex part of 11C link material 12 Transbar link (forged product) 12B link recess 12C link protrusion 22 Upper arm (forged product) 22A Upper arm part 22B Upper arm attachment

Continuation of the front page (56) Reference JP 63-100151 (JP, A) JP 6218481 (JP, A) JP 62-279047 (JP, A) JP 6-7877 (JP , A) JP-A 7-116764 (JP, A) JP-A 5-38543 (JP, A) JP-A 6-190493 (JP, A) JP-A 4-210842 (JP, A) 5-241 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B21J 1/00-13/14 B21J 17/00-19/04 B21K 1/00-31/00 B22D 25 / 02

Claims (5)

(57) [Claims] 1. Forming a forging material by casting,
The forging material is forged into a forged product of the desired shape.
Runisaishi, of the forging material, part wall thickness decreases by forging
The rolling reduction of 15% or more and the front of the forging
Plastic flow due to extrusion, backward extrusion or upset processing
The stress of the portion formed by the movement is set to 50 MPa or more,
A method for manufacturing a forged product characterized by the following. 2. The forging material is thinned by forging.
The reduction ratio of the part that becomes large is 15% or more, and forging
Front extrusion, rear extrusion or upset processing during manufacturing
Stress of the part formed by plastic flow due to
The method for manufacturing a forged product according to claim 1, wherein the forging product is formed by casting as described above. 3. The forged product is a disk for a road wheel, and a bottom wall portion of a recess corresponding to a portion where the wall thickness is thinned by forging in a spoke portion where the recess and the protrusion are formed has a rolling reduction of 15% or more. Forward extrusion by forging with
However, the protruding portion of the convex portion corresponding to the portion formed by plastic flow in the backward extrusion or upset processing has a stress of 50MP.
The method for manufacturing a forged product according to claim 1 or 2, wherein a or more is obtained. 4. The method for manufacturing a forged product according to claim 3 , wherein an outer rim is integrally formed with the disc. 5. A strain amount of 0.% instead of a rolling reduction of 15% or more.
The method for producing a forged product according to any one of claims 1 to 4 , wherein the forged product is 25 or more.