JPH0976042A - Production of structural member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily improve the characteristics and joining strength of both parts in producing a piston consisting of a main body part having heat resistance and an outer peripheral part having wear resistance. SOLUTION: The production consists of a process to obtain the inner/outer two layer structured billet composing of a first columnar green compact and a second tubular green compact, a process to obtain the extruded material, by subjecting the billet to extrusion, in which the inside region formed from the first green compact corresponds to a main body part 4 of a piston 1 and the outside region formed from the second green compact corresponds to an outer peripheral part 8 of the piston 1, a process to obtain plural crude materials for forging by subjecting the extruded material to cutting in the direction intersecting to the extruding direction and a process by subjecting the crude materials to forging.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structural member, and more particularly to a method of manufacturing a structural member having a main body portion and an outer peripheral portion surrounding the main body portion and having characteristics different from those of the main body portion.

The structural member may be, for example, a piston for an internal combustion engine made of an Al alloy. In this case, the main body is required to have heat resistance, and the outer peripheral portion is required to have wear resistance and seizure resistance.

[0003]

2. Description of the Related Art Conventionally, as a piston forging material,
For example, a disc made of a heat resistant Al alloy and a columnar body made of a wear resistant Al alloy are used.

In the forging process, the head portion is formed of a disk and the skirt portion having a pin boss portion is formed of a columnar body, and at the same time, the head portion and the skirt portion are joined.

[0005]

However, according to the conventional method, since the material for forging is a molten material (meaning the material obtained through the melting step), there are great restrictions on the improvement of the material and therefore the head portion. And there is a limit to improving the characteristics of the skirt.

Further, the joint strength between the head portion and the skirt portion by the forging process is relatively low, and therefore it is desired to further improve the joint strength.

[0007]

According to the present invention, it is possible to easily improve the characteristics of the main body portion and the outer peripheral portion of the structural member, and to increase the bonding strength between the main body portion and the outer peripheral portion. It is an object of the present invention to provide the above manufacturing method capable of

[0008] To achieve the above object, according to the present invention,
In manufacturing a structural member including a main body portion and an outer peripheral portion surrounding the main body portion and having characteristics different from those of the main body portion, a first green compact and a first green compact A step of obtaining a billet having a two-layer structure composed of a second green compact having characteristics different from those of the body, and the billet being extruded to form the first billet.
And a step of obtaining an extruded material in which an inner region formed by one of the second green compacts corresponds to the main body portion and an outer region formed by the other one corresponds to the outer peripheral portion, and the extruded material, A method for manufacturing a structural member is provided, which includes a step of performing a cutting process in a direction intersecting the extrusion direction to obtain a plurality of forging materials, and a step of forging the materials.

By adopting the above-mentioned means, it is possible to easily respond to the improvement of the characteristics of the main body portion and the outer peripheral portion of the structural member by changing the powder mixture.

Further, since the inner and outer regions formed of the first and second green compacts are joined by extrusion, the joining strength between the main body portion corresponding to the inner region and the outer peripheral portion corresponding to the outer region. Is high and its reliability is high.

Further, since a plurality of forging materials can be obtained from the extruded material, it is effective in improving the mass productivity of structural members.

Another object of the present invention is to provide the above manufacturing method having substantially the same advantages.

According to the present invention for achieving the above object,
In manufacturing a structural member including a main body portion and an outer peripheral portion surrounding the main body portion and having characteristics different from those of the main body portion, a metal hollow body and the hollow body are filled, and Hollow body and a step of obtaining a billet consisting of an aggregate of metal powders having different characteristics, and subjecting the billet to extrusion processing, the inner region formed by the aggregate corresponds to the main body portion, and A step of obtaining an extruded material in which the outer region formed by the hollow body corresponds to the outer peripheral portion, and a step of subjecting the extruded material to a cutting process in a direction intersecting the extrusion direction to obtain a plurality of forging materials; And a method of manufacturing a structural member using the step of forging the material.

If the above-mentioned means is adopted, there is a limitation in improving the characteristics of the outer peripheral portion of the structural member, but it is possible to easily cope with the improvement of the characteristics of the main body portion, and the bonding strength between the main body portion and the outer peripheral portion. And mass productivity of structural members can be improved.

Further, the concept of an aggregate of metal powders includes
This includes the case where the metal powder is used as it is in addition to the green compact, so that the billet can be easily manufactured.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a piston 1 for an internal combustion engine as a structural member is made of an Al alloy and has a head portion 2
And a cylindrical main body 4 which constitutes both pin bosses 3, and an outer peripheral portion 8 which surrounds the main body 4 and constitutes a top land portion 5, a ring zone 6 and a skirt portion 7. The main body 4 is made of, for example, an Al alloy containing less than 3% by weight of an alloy element and has heat resistance, and the outer peripheral portion 8 has, for example, 10% by weight or more of Si and 0.5% by weight.
It is made of the above Al alloy containing Cu, Mg, Ni and Fe, JIS 4000 series Al alloy, etc. and has wear resistance and seizure resistance.

Hereinafter, the production of the piston 1 will be specifically described by way of examples. In the first embodiment,
The numerical value in () shows an upper limit, a lower limit, or a suitable range. Example 1 A. Manufacture of Forging Material (1) As shown in FIG. 2, in consideration of heat resistance, the composition is Al-2 wt% C-0.2 wt% O, grain size 0.6.
Using an Al alloy powder of mm or less (1 mm or less), pressure 270
By performing cold isostatic pressing (CIP) under the condition of 0 bar (2000 bar or more), the diameter is about 76 mm and the length is 16 mm.
A first green compact 9 having a cylindrical shape of 5 mm was obtained. (2) As shown in FIG. 3, in consideration of wear resistance and seizure resistance, the composition is Al-12 wt% Si-3 wt% C.
u-1 wt% Mg-5 wt% Fe, particle size 80 μm
The following (100 μm or less) Al alloy powder was used, and the pressure was 2
By performing cold isostatic pressing (CIP) under the condition of 700 bar (2000 bar or more), the second green compact 10 having a tubular shape having an outer diameter of 145 mm, an inner diameter of about 76 mm, and a length of 165 mm.
I got (3) As shown in FIG. 4, the first green compact 9 was fitted into the second green compact 10 to obtain a billet 11 having an inner-outer two-layer structure. (4) The billet 11 is placed in a heating furnace and held for 5.5 hours (2 hours or more, preferably 5 to 6 hours) to perform degassing treatment, and the extrusion temperature is 470.
The temperature was raised to 0 ° C (300 ° C or higher, preferably 420 to 520 ° C). (5) As shown in FIG.
No. 2 container 13 and then the ram 14 is operated to extrude the billet 11 from the die hole 15 of the die 17 at a ratio of 6.4 (4 or more, preferably 6.25 to 11.
0) and extruded material 16 having an outer diameter of 57 mm shown in FIG.
I got In this extruded material 16, a portion on the front side in the extruding direction and an unpressed portion are cut off.

In the extruded material 16, the inner region 18 formed of the first green compact 9 corresponds to the main body 4 of the piston 1, and the outer region 1 formed of the second green compact 10.
Reference numeral 9 corresponds to the outer peripheral portion 8 of the piston 1. (6) As shown in FIG. 7, the extruded material 16 was cut in a direction intersecting with the extruding direction a to obtain a plurality of forging materials 20. In this case, the length of the material 20 is 45 mm
Was set to. B. Manufacture of Piston (1) The forging material 20 is placed in a heating furnace and held for 90 minutes (120 minutes or less, about 0.5 minutes in the case of high frequency heating) to obtain a forging temperature of 420 ° C. (30
The temperature was raised to 0 ° C or higher). (2) As shown in FIG. 8, the forging material 20 was installed in the die hole 23 of the die 22 of the forging machine 21 such that the outer region 19 thereof faces the inner peripheral surface of the die hole 23. (3) As shown in FIG. 9, to lower the punch 24, is subjected to forging under conditions of compression pressure ^{24.7t / cm 2 (20t / cm} 2 or higher) in the material 20, from the Al alloy having a heat resistance A piston material 25 including the configured cylindrical main body 4 and the outer peripheral portion 8 made of an Al alloy having wear resistance and seizure resistance was obtained. (4) The piston material 25 was subjected to predetermined machining to obtain the piston 1.

By adopting the above-mentioned means, it is possible to easily respond to the improvement of the characteristics of the main body portion 4 and the outer peripheral portion 8 of the piston 1 by changing the powder mixture.

Since the inner and outer regions 18 and 19 formed of the first and second green compacts 9 and 10 are joined by extrusion, the inner region 18 corresponds to the main body 4 and the outer region 19. The bonding strength with the corresponding outer peripheral portion 8 is high, and its reliability is also high.

Furthermore, since a plurality of forging materials 20 can be obtained from the extruded material 16, it is effective in improving the mass productivity of the piston 1.

For centering the first and second green compacts 9 and 10, a means of taper-fitting these 9 and 10 may be considered. [Example 2] A. Manufacturing of Forging Material (1) As shown in FIGS. 10 and 11, JIS 4032, which is an Al alloy, is taken into consideration in consideration of wear resistance and seizure resistance.
A hollow body (metal hollow body) 28 having a tubular portion 26 made of the same and a lid portion 27 made of the same material was prepared. The cylindrical portion 26 has an outer diameter of 145 mm, an inner diameter of 76 mm, and a length of 165 mm.

In consideration of heat resistance, the composition is Al-2 wt% C-0.2 wt% O, and the grain size is 0.
Prepare an Al alloy powder (metal powder) 29 of 6 μm or less,
This was filled in the tubular portion 26, then the opening of the tubular portion 26 was closed by the lid portion 27, and then the tubular portion 26 and the lid portion 27 were welded to obtain the billet 11 having an inner-outer two-layer structure. (2) The billet 11 was placed in a heating furnace and held for 5.5 hours to raise the temperature to 470 ° C. which is the extrusion temperature. (3) As in the first embodiment, as shown in FIG. 5, the billet 11 is installed in the container 13 of the extruder 12, and then the ram 14 is operated to extrude the billet 11 through the die hole 15 at an extrusion ratio of 6.4. Extrusion was carried out in the same manner as in Example 1 to obtain an extruded material 16 having an outer diameter of 57 mm shown in FIG.

In the extruded material 16, Al alloy powder 29
The inner region 18 formed of the hollow body 28 corresponds to the main body portion 4 of the piston 1, and the outer region 19 of the hollow body 28 corresponds to the outer peripheral portion 8 of the piston 1. (4) As in Example 1, as shown in FIG.
A plurality of forging materials 20 were obtained by subjecting 6 to a cutting process in a direction intersecting the extrusion direction a. In this case, material 20
The length was set to 45 mm. B. Production of Piston (1) The forging material 20 was placed in a heating furnace and held for 90 minutes to raise the temperature to a forging temperature of 420 ° C. (2) As in Example 1, as shown in FIG.
The forging material 20 in the die hole 23 of the die 22 of
Was installed such that the outer region 19 thereof faces the inner peripheral surface of the die hole 23. (3) As in the first embodiment, as shown in FIG.
The material 20 under the condition that the compression pressure is 24.7 t / cm ^2.
A piston material 25 having a cylindrical main body 4 made of Al alloy having heat resistance and an outer peripheral portion 8 made of Al alloy having wear resistance and seizure resistance Obtained. (4) The piston material 25 was subjected to predetermined machining to obtain the piston 1.

If the above-mentioned means is adopted, there is a relatively large restriction on the characteristic improvement in the outer peripheral portion 8 of the piston 1, but it is possible to easily respond to the characteristic improvement of the main body portion 4, and It is possible to improve the joint strength with the outer peripheral portion 8 and the mass productivity of the piston 1.

Further, since the Al alloy powder 29 is used as it is, the manufacture of the billet 11 can be simplified. A green compact made of the Al alloy powder may be fitted into the hollow body 28.

As shown in FIG. 12, a billet 11 having an inner-outer two-layer structure is constituted by tubular first and second green compacts 9 and 10, and an extruded material is doubled by using a mandrel for extrusion. It can also be formed in a tubular shape. Example 1
In the above, both green compacts 9 and 10 are molded into a thick disk shape,
It is also possible to obtain an extruded material having an inner / outer two-layer structure by arranging the second green compact 10 on the front side in the extruding direction and performing the extruding process.

[0028]

According to the present invention, by adopting the means specified above, it is possible to easily respond to the improvement of the characteristics of the main body portion and the outer peripheral portion of the structural member, or the main body portion. It is possible to provide a manufacturing method with good mass productivity, which can increase the bonding strength between the main body portion and the outer peripheral portion.

[Brief description of drawings]

FIG. 1 is a sectional view of a piston.

FIG. 2 is a perspective view of a first green compact.

FIG. 3 is a perspective view of a second green compact.

FIG. 4 is a perspective view showing a first example of a billet.

FIG. 5 is a cross-sectional view of the extruder.

FIG. 6 is a perspective view of an extruded material.

FIG. 7 is a perspective view showing a state in which a forging material is cut out from an extruded material.

FIG. 8 is a cross-sectional view showing a state before processing in a forging machine.

FIG. 9 is a cross-sectional view showing a state after processing in a forging machine.

FIG. 10 is a perspective view showing a second example of a billet.

FIG. 11 is a sectional view taken along line 11-11 of FIG. 10;

FIG. 12 is a perspective view showing a third example of a billet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piston (structural member) 4 Main part 8 Outer peripheral part 9 1st green compact 10 2nd green compact 11 Billet 16 Extruded material 18 Inner region 19 Outer region 20 Forging material 28 Hollow body 29 Al alloy powder (metal) Powder) a Extrusion direction

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F16J 1/00 F16J 1/00

Claims (3)

[Claims] 1. A structural member comprising a main body (4) and an outer peripheral portion (8) surrounding the main body (4) and having different characteristics from the main body (4) is manufactured. In this case, a billet (11) having a two-layer structure, which comprises a first green compact (9) and a second green compact (10) having characteristics different from those of the first green compact (9). ) And extruding the billet (11) to obtain the first and second green compacts (9, 1).
The extruded material (1) in which the inner region (18) formed by one of the above (0) corresponds to the main body part (4) and the outer region (19) formed by the other corresponds to the outer peripheral part (8).
6), a step of cutting the extruded material (16) in a direction intersecting the extrusion direction (a) to obtain a plurality of forging materials (20), and the material (20). A method for manufacturing a structural member, comprising: a step of performing a forging process. 2. In the billet (11), the first green compact (9) has one of a cylindrical shape and a tubular shape, and the second green compact (10) has a tubular shape. The method for manufacturing a structural member according to claim 1, wherein the first green compact (9) is fitted together. 3. A structural member comprising a main body part (4) and an outer peripheral part (8) surrounding the main body part (4) and having characteristics different from those of the main body part (4). First, the metal hollow body (28) and the metal powder (2) filling the hollow body (28) and having different characteristics from the hollow body (28).
9) a step of obtaining a billet (11) comprising the aggregate, and the billet (11) is extruded so that the inner region (18) formed by the aggregate corresponds to the main body part (4). And a step of obtaining an extruded material (16) in which the outer region (19) formed by the hollow body (28) corresponds to the outer peripheral portion, and the extruded material (16) having an extruding direction (a) thereof. A step of obtaining a plurality of forging materials (20) by performing a cutting process in an intersecting direction;
0) a step of performing forging processing, and a method of manufacturing a structural member.