WO2006135112A1

WO2006135112A1 - Upsetting method and upsetting apparatus

Info

Publication number: WO2006135112A1
Application number: PCT/JP2006/312567
Authority: WO
Inventors: Atsushi Otaki
Original assignee: Showa Denko K.K.
Priority date: 2005-06-17
Filing date: 2006-06-16
Publication date: 2006-12-21
Also published as: EP1901865A4; EP1901865A1; KR20080011701A; US20090217730A1

Abstract

An upsetting method capable of eliminating a correction step by preventing occurrence of quench distortion is provided. The method includes the step of preparing an upsetting apparatus 10 equipped with a forming die 11 and a guide 20 having an insertion hole 21 for securing a diameter expansion scheduled portion 2 of the bar-shaped raw material 1 in a buckling preventing state and a punch 30. The diameter expansion scheduled portion 2 of the raw material 1 in a heated state is disposed in the insertion hole 21 of the guide 20 in a heated state, and the tip end portion of the guide 20 is disposed in the cavity 12 of the forming die 11 adjusted in temperature so as to be below a temperature of the raw material 1, and the raw material is secured to the securing portion 13 of the forming die 11. With this state, the guide 20 is moved in a direction opposite to a moving direction 37 of the punch 30 while axially pressurizing the diameter expansion scheduled portion 2 of the raw material 1 by moving the punch 30, to thereby expand the diameter expansion scheduled portion 2 of the raw material 1 exposed between a tip end portion of the guide 20 and the securing portion 13 of the forming die 11 within the cavity 12 of the forming die 11.

Description

DESCRIPTION

UPSETTING METHOD AND UPSETTING APPARATUS

This application claims priority to Japanese Patent

Application No. 2005-177991 filed on June 17, 2005, and U.S. Provisional Application No. 60/693,407 filed on June 24, 2005, the entire disclosures of which are incorporated herein by reference in their entireties.

Cross Reference to Related Applications

This application is an application filed under 35 U. S. C. §lll(a) claiming the benefit pursuant to 35 U. S. C. §119(e)(l) of the filing date of U.S. Provisional Application No.60/693, 407 filed on June 24, 2005, pursuant to 35 U. S. C. §lll(b).

Technical Field

The present invention relates to an upsetting method and an upsetting apparatus for manufacturing various products, such as, e.g., an arm, a connecting rod, or a double-headed piston of compressors for use in vehicles (automobiles or railroad vehicles) . Background Art

The following description sets forth the inventor ' s knowledge

> of related art and problems therein and should not be construed as an admission of knowledge in the prior art.

As an upsetting method for radially expanding a diameter expansion scheduled portion of a bar-shaped rawmaterial, for example, the following method is known. In this method, initially, an upsetting apparatus equipped with a die having a securing portion for securing a bar-shaped raw material, a guide having an insertion hole for holding the diameter expansion scheduled portion of the rawmaterial in a buckling preventing manner, and a punch is prepared. Then, a raw material is secured to the securing portion of the die, and the diameter expansion scheduled portion of the raw material is inserted in the insertion hole of the guide. Subsequently, the guide is moved in a direction opposite to the moving direction of the punch while axially pressuring the diameter expansion scheduled portion of the raw material by moving the punch, to thereby radially expand the diameter expansion scheduled portion exposed between the tip end portion of the guide and the securing portion of the die (see, e.g., Japanese Unexamined Laid-open Patent Publication No. 2005-59097).

This upsetting method has advantages that, for example, buckling of raw material which sometimes occurs at the time of upsetting can be prevented, resulting in an upsetting manufactured product with high quality.

In the meantime, as a method for pressing a raw material of a plate shape, not a bar shape, for example, methods disclosed in Japanese Unexamined Laid-open Patent Publication Nos. 2002-248525 and 2005-59010 are known.

In general, an upsetting manufactured product obtained by the above-mentioned upsetting method is sequentially subjected to solution heat treatment, quench hardening, aging treatment, etc., as heat treatment after the upsetting. This heat treatment is important processing for giving prescribed intensity (e.g. , tensile strength, proof stress) to an upsetting manufactured product.

However, subjecting the upsetting manufactured product to quench hardening among the heat treatments may sometimes cause quench distortion. Therefore, an additional correction step for correcting the quenching distortion is required after the quench hardening. Consequently, the number of steps increases , resulting in an increased manufacturing cost.

The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention . Indeed, certain features of the invention may be capable of overcoming certain disadvantages, while still retaining some or all of the features , embodiments , methods , and apparatus disclosed therein.

Other objects and advantages of the present invention will be apparent from the following preferred embodiments.

Disclosure of Invention

The preferred embodiments of the present invention have been developed in view of the above-mentioned and/or other problems in the related art . The preferred embodiments of the present invention can significantly improve upon existing methods and/or apparatuses .

Among other potential advantages , some embodiments can provide an upsetting method capable of eliminating a correction step by preventing occurrence of quench distortion.

Among other potential advantages , some embodiments can provide an upsetting manufactured product obtained by the upsetting method.

Among otherpotential advantages , some embodiments can provide an upsetting apparatus used for the upsetting method.

The present invention provides the following means. [1] An upsetting method, comprising the steps of: preparing an upsetting apparatus including a forming die having a securing portion for securing a bar-shaped raw material and a cavity, a guide having an insertion hole for holding a diameter expansion scheduled portion of the raw material in a buckling preventing state, the insertion hole being penetrated and extended in an axial direction, and a punch; disposing the diameter expansion scheduled portion of the raw material in a heated state in the insertion hole of the guide in a heated state; disposing a tip end portion of the guide in the cavity of the forming die adjusted in temperature so as to be below temperature of the raw material; securing the rawmaterial to the securingportion of the forming die; and while keeping the above state, moving the guide in a direction opposite to amoving direction of the punchwhile axiallypressurizing the diameter expansion scheduled portion of the raw material by moving the punch, to thereby expand the diameter expansion scheduled portion of the raw material exposed between the tip end portion of the guide and the securing portion of the forming die within the cavity of the forming die.

[2] The upsetting method as recited in the aforementioned Item 1, wherein the diameter expansion scheduled portion of the rawmaterial is placed in the insertion hole of the guide by inserting the raw material in a heated state into the insertion hole of the guide in a heated state from the insertion hole inlet portion formed at a rear end portion of the guide.

[3] The upsetting method as recited in the aforementioned Item 1 or 2, wherein the diameter expansion scheduled portion of the raw material is axially pressurized with the punch simultaneous with or immediately after the securing of the raw material to the securing portion of the forming die.

[4] The upsetting method as recited in any one of the aforementioned Items 1 to 3 , wherein the securing portion of the forming die is provided with a raw material fixing insertion hole communicated with the cavity, wherein the forming die has a plurality of divided members divided by the dividing plane vertically dividing the insertion hole and the cavity, and wherein the raw material is secured to the securing portion of the forming die by clamping a non-diameter-expansion scheduled portion of the raw material between divided grooves of the insertion holes of a plurality of divided members of the forming die .

[5] The upsetting method as recited in any one of the aforementioned Items 1 to 4 , wherein the raw material is heated to solution heat treatment temperature of the raw material. [6] The upsetting method as recited in the aforementioned Item 5, wherein the raw material is made of heat-treatment type aluminumalloy, andwherein the rawmaterial is heatedto a temperature range of 400 to 570 ⁰C.

[ 7 ] The upsetting method as recited in the aforementioned Item 6, wherein the forming die is adjusted in temperature so as to fall within the temperature range of 5 to 120 °C.

[8] The upsetting method as recited in the aforementioned Item 6 or 7 , wherein the guide is heated to a temperature range of 170 to 500 ⁰C.

[9] The upsetting method as recited in any one of the aforementioned Items 1 to 8, wherein the raw material has a non-diameter-expansion scheduled portion as its axial intermediate portion and diameter expansion scheduled portions at its axial both end portions, wherein the upsetting apparatus has two cavities in the forming die, two guides, and two punches, wherein each diameter expansion scheduled portion of the raw material in a heated state is placed in the corresponding insertion hole of the guide in a heated state, wherein the tip end portion of each guide is placed in the cavity of the forming die adjusted in temperature so as to be below the temperature of the raw material. wherein the raw material is secured to the securing portion of the forming die , and wherein, while keeping the aforementioned state, both the diameter expansion scheduled portions of the raw material are simultaneously expanded ^"in diameter by moving each guide in a direction opposite to the moving direction of the corresponding punch while simultaneously axially pressurizing each diameter expansion scheduled portion of the raw material with the corresponding punch.

[10] An upsetting manufactured product obtained by the upsetting method as recited in any one of the aforementioned Items 1 to 9.

[11] A method of manufacturing an upsetting manufactured product, comprising the steps of: subjecting a raw material to the upsetting method as recited in any one of the aforementioned Items 1 to 9; and thereafter subjecting the raw material to aging treatment.

[12] An upsetting apparatus, comprising: a forming die having a securing portion for securing a bar-shaped raw material and a cavity; a guide having an insertion hole for holding a diameter expansion scheduled portion of the raw material in a buckling preventing state, the inserting hole being penetrated and extended in an axial direction; apunch for axial pressurizing the diameter expansion scheduled portion of the raw material placed in the insertion hole of the guide ; a guide driving apparatus for moving the guide in a direction opposite to a moving direction of the punch; a raw material heating device for heating the raw material; a forming die temperature adjusting device for adjusting the forming die so as to be a temperature below a heating temperature of the raw material by the raw material heating device; and a guide heating device for heating the guide.

[ 13 ] The upsetting apparatus as recited in the aforementioned

Item 12, further comprising a raw material insertion apparatus for inserting the raw material into the insertion hole of the guide from the insertion hole inlet portion formed at a rear end portion of the guide .

[ 14 ] The upsetting apparatus as recited in the aforementioned Item 12 or 13, wherein the securing portion of the forming die has a raw material fixing insertion hole communicated with the cavity, andwherein the forming die has a plurality of dividedmembers divided by a dividing plane vertically dividing the insertion hole and the cavity, whereby the raw material is secured to the securing portion by clamping the non-diameter-expansion scheduled portion of the raw material between the divided grooves of the insertion hole of the plurality of divided members .

[15] The upsetting apparatus as recited in any one of the aforementioned Items 11 to 14, wherein the raw material heating device is configured to heat the raw material to solution heat treatment temperature of the raw material.

[ 16 ] The upsetting apparatus as recited in the aforementioned Item 15, wherein the raw material is made of heat-treatment type aluminum alloy, and wherein the raw material heating device is configured to heat the raw material to a temperature range of 400 to 570 ^βC.

[ 17 ] The upsetting apparatus as recited in the aforementioned Item 16, wherein the forming die temperature adjusting device is configured to adjust the forming die to a temperature range of 5 to 120 ⁰C.

[ 18 ] The upsetting apparatus as recited in the aforementioned Item 16 or 17, wherein the guide heating device is configured to heat the guide to a temperature range of 170 to 500 ⁰C.

[19] An upsetting apparatus for expanding axial both end portions of a bar-shaped rawmaterial as diameter expansion scheduled portions, the raw material having an axial intermediate portion as a non-diameter-expansion scheduled portion, the apparatus comprising: a forming die having a securing portion for securing the raw material and two cavities; two guides each having an insertion hole for holding each diameter expansion scheduled portion of the raw material secured to the securing portion of the forming die in a buckling preventing state, the insertion hole being penetrated through the guide and extended in an axial direction; two punches each for axially pressurizing each diameter expansion scheduled portion of the raw material placed in the insertion hole of each guide; two guide driving apparatus each for moving the corresponding guide in a direction opposite to a moving direction of the corresponding punch; a raw material heating device configured to heat the raw material; a formingdie temperature adjusting device configured to adjust the forming die so as to be a temperature below the heating temperature of the raw material by the raw material heating device; and two guide heating devices each configured to heat each guide.

[ 20 ] The upsetting apparatus as recited in the aforementioned

Item 19, further comprising a raw material insertion apparatus for inserting the raw material into the insertion hole of one of guides from the insertion hole inlet portion formed at a rear end portion of the guide. [ 21 ] The upsetting apparatus as recited in the aforementioned

Item 19 or 20, wherein the securing portion of the forming die has a raw material fixing insertion hole communicated with the cavity, andwherein the forming die has a plurality of dividedmembers divided by a dividing plane vertically dividing the insertion hole and both the cavities, whereby the raw material is secured to the securing portion by clamping the non-diameter-expansion scheduled portion of the raw material between the divided grooves of the insertion holes of the plurality of divided members.

[22] The upsetting apparatus as recited in any one of the aforementioned Items 19 to 21, wherein the raw material heating device is configured to heat the raw material to solution heat treatment temperature of the raw material.

[ 23 ] The upsetting apparatus as recited in the aforementioned Item 22, wherein the raw material is made of heat-treatment type aluminum alloy, and wherein the raw material heating device is configured to heat the raw material to a temperature range of 400 to 570 ⁰C.

[ 24 ] The upsetting apparatus as recited in the aforementioned Item 23, wherein the forming die temperature adjusting device is configured to adjust the forming die to a temperature range of 5 to 120 ⁰C. [ 25 ] The upsetting apparatus as recited in the aforementioned Item 23 or 24, wherein the guide heating device is configured to heat the guide to a temperature range of 170 to 500 ⁰C.

The present invention has the following effects.

According to the invention as recited in the aforementioned Item [1], since the raw material and the guide are heated and the forming die is adjusted in temperature so as to be a prescribed temperature at the time of expanding the diameter expansion scheduled portion of the raw material, the diameter expanded portion can be quenched while expanding the diameter expansion scheduled portion of the rawmaterial. Therefore, it is not necessary to execute quench hardening separately. Furthermore, since the raw material is secured to the securing portion of the forming die and the diameter expansion scheduled portion of the raw material is disposed in the cavity in an expanded state at the time of quench hardening, possible quenchdistortionwhichmaybeproducedat the time of quenchhardening can be prevented. Therefore, a correction step for correcting the quench distortion can be eliminated, resulting in a reduced manufacturing cost .

According to the invention as recited in the aforementioned Item [ 2 ] , the raw material in a heated state can be set to the forming die and the guide while keeping the high temperature as higher as possible. Therefore, a problem that inadequate quench hardening portions are generated in the raw material due to the temperature drop of the raw material before the upsetting can be prevented, which makes it possible to assuredly increase the intensity of the upsetting manufactured product.

According to the invention as recited in the aforementioned Item [3], it is possible to prevent a problem of occurrence of temperature variation of the raw material due to the contact with the securing portion of the forming die, which makes it possible to uniformly maintain the temperature of the raw material until immediately before the upsetting. Therefore, the intensity of the upsetting manufactured product can be assuredly increased.

According to the invention as recited in the aforementioned Item [4], the raw material can be assuredly fixed to the securing portion of the forming die, and quench distortion can be prevented assuredly. Furthermore, since the raw material is quickly brought into contact with the forming die at the time of securing the raw material, the raw material can be quickly cooled, resulting in enhanced quench hardening .

According to the invention as recited in the aforementioned Item [5], the quench hardening effect can be demonstrated assuredly, the intensity of the upsetting manufactured product can be enhanced assuredly. According to the invention as recited in the aforementioned Item [6] , solution heat treatment can be assuredly executed to the raw material made of heat-treatment type aluminum alloy.

According to the invention as recited in the aforementioned Item [7], the quench hardening effect of the raw material made of heat-treatment type aluminum alloy can be demonstrated more assuredly, and the intensity of the upsetting manufactured product can be enhanced more assuredly.

According to the invention as recited in the aforementioned Item [8], the quench hardening effect of the raw material made of heat-treatment type aluminum alloy can be demonstrated more assuredly, and the intensity of the upsetting manufactured product can be enhanced more assuredly.

According to the invention as recited in the aforementioned Item [ 9 ] , an upsetting manufactured product having diameter expanded portions at the axial both end portions can be manufactured efficiently.

According to the invention as recited in the aforementioned Item [10], an upsetting manufactured product with high intensity can be provided. According to the invention as recited in the aforementioned Item [11] , an upsetting manufactured product with higher intensity can be provided.

According to the invention as recited in the aforementioned Item [12] to [25] , an upsetting apparatus which can be used suitably for the aforementioned upsetting method according to the present invention can be provided.

Brief Description of Drawings

The preferred embodiments of the present invention are shown by way of example, and not limitation, in the accompanying figures, in which:

Fig. 1 is a schematic exploded perspective view showing an upsetting apparatus according to an embodiment of the present invention;

Fig .2 is a schematic plan view showing the state before setting a raw material to a forming die and both guides of the apparatus;

Fig. 3 is a schematic plan view showing the state in which a raw material is being inserted in an insertion hole of one of guides with the apparatus; Fig. 4 is a schematic plan view showing the state in which diameter expansion scheduled portions of the rawmaterial is disposed in the insertion hole of both guides with the apparatus;

Fig. 5A is a schematic plan view showing the state in which the raw material is set to a forming die and both guides with the apparatus ;

Fig. 5B is a cross-sectional view taken along the line A-A in Fig. 5A;

Fig. 6A is a schematic plan view showing the state in which the diameter expansion scheduled portions of the raw material are being expanded with the apparatus;

Fig. 6B is a cross-sectional view taken along the line B-B in Fig. 6A;

Fig. 7A is a schematic plan view showing the state in which the diameter expansion scheduled portions of the raw material were expanded in diameter with the apparatus ;

Fig. 7B is a cross-sectional view taken along the line C-C in Fig. 7A;

Fig. 8 is a schematic plan view showing the state in which an upsettingmanufactured product is to be removed from the apparatus ;

Fig .9 is a perspective view showing the upsetting manufactured product manufactured by the apparatus ;

Fig. 1OA is a schematic side view of an upsetting manufactured product showing the warpage of the upsetting manufactured product;

Fig.1OB is a schematic plan view of the upsetting manufactured product showing the bend of the upsetting manufactured product;

Fig. 11 is a schematic plan view of the upsetting manufactured product showing the extraction positions of test pieces; and

Fig.12 is a perspective view of another upsetting manufactured product manufactured by the apparatus.

Best Mode for Carrying Out the Invention

Next , an embodiment of the present invention will be explained with reference to drawings .

In Fig. 1, the reference numeral "10" denotes an upsetting apparatus according to an embodiment of the present invention. The reference numeral "1" denotes a raw material. In Fig. 9, the" reference numeral "5" denotes an upsetting manufactured product manufactured by the upsetting apparatus 10 of this embodiment. This upsetting manufactured product 5 is used as a preform for manufacturing arms for vehicles, such as, e.g., cars or railroad vehicles .

As shown in Figs . 1 and 2 , the raw material l is a solid and straight bar-shaped material made of heat-treatment type aluminum alloy. The raw material 1 is round in cross-section and constant in diameter in the axial direction.

As the aforementionedheat-treatment type aluminum alloywhich is the material of the raw material 1 , when shown by the aluminum alloy number based on JIS (Japanese Industrial Standards), 2xxx seriess, 6xxx seriess, and 7xxx seriess aluminum alloy can be exemplified.

In the present invention, the material of the raw material 1 is not limited to aluminum or aluminum alloy, but can be any metal other than aluminum, such as, e.g., brass, copper, steel, stainless steel. Moreover, the raw material 1 is not limited to a circular shape in cross-section, and can be a polygonal shape, such as, e.g. , a quadrangular shape or a hexagon shape .

This raw material 1 has diameter expansion schedule portons at its axial prescribed portions. In this embodiment, the axial intermediate portion of the raw material 1 constitutes a non-diameter-expansion scheduled portion 3, and the axial end portions thereof constitute diameter expansion scheduled portions 2 and 2. When each of the diameter expansion scheduled portions 2 and 2 of the raw material 1 is expanded in diameter into a designed shape, diameter expandedportions 6 and 6 eachhaving an approximately circular-shape will be formed at the axial both end portions as shown in Fig. 9. Each diameter expanded portion 6 has laterally expanded portions of an approximately circular-arc shape and has flat surfaces at its thickness sides. The reference numeral "7" denotes a non-diameter expanded portion of the upsetting manufactured product 5 corresponding to the non-diameter-expansion scheduled portion 3 of the raw material 1.

In this upsetting manufactured product 5, each diameter expanded portion 6 corresponds to a connecting portion (e.g., a bush mounting portion) to be connected to another component of an arm for vehicles and the non-diameter expanded portion 7 corresponds to a shank of the arm.

The upsetting apparatus 10 is used to expand each diameter expansion scheduled portion 2 of the raw material 1. As shown in Figs . 1 and 2 , this upsetting apparatus 10 is provided with a forming die 11, two guides 20 and 20, two guide driving apparatuses 25 and 25, two punches 30 and 30, two punch driving apparatuses 35 and 35, a raw material heating device 70, a forming die temperature adjusting device 40," and two guide heating devices 50 and 50, and a raw material insertion apparatus 60. In Fig. 1, for an easy understanding of the structure of the upsetting apparatus 10, two guide driving apparatus 25 and 25 are not illustrated.

As shown in Fig. 1, the forming die 11 has a securing portion 13 for securing the raw material 1 and two cavities 12 and 12 formed at both sides of the securing portion 13. The securing portion 13 has a raw material fixing insertion hole 14 extended in the axial direction of the forming die 11 and communicated with both cavities 12 and 12. The non-diameter-expansion scheduled portion 3 of the raw material 1 is fitted in this insertion hole 14 so that the raw material 1 is fixed immovably in the axial direction thereof .

This forming die 11 consists of front and rear divided members 11a and 11a divided by a dividing plane 15 vertically dividing the insertion hole 14 and both the cavities 12 and 12.

Connected to the forming die 11 are forming die driving devices 17 and 17 for moving both the divided members 11a and 11a in a direction of making these members separate and a direction of making them approach. In this embodiment, the forming die driving device 17 is constituted by a fluid pressure cylinder, such as, e.g. , an oil pressure cylinder or a gas-pressure cylinder . The operation of these forming die driving device 17 and 17 causes separation or approach of the divided members 11a and 11a. In this forming die 11, when the non-diameter-expansion scheduled portion 3 of the raw material 1 is clamped between the divided grooves of the insertion hole 14 of the divided members 11a and 11a by making both the divided members 11a and 11a approach, the raw material 1 can be secured in a state in which the non-diameter-expansion scheduled portion 3 of the raw material 1 is inserted in the insertion hole 14 formed by the joining of the divided grooves of the insertion hole 14 of the divided members 11a and 11a.

The forming die temperature adjusting device 40 is used to adjust the temperature of the forming die 11 so that the temperature of the forming die 11 is kept below the temperature of the rawmaterial 1 in a heated state. In this embodiment, as the forming die temperature adjusting device 40, a liquid cooling jacket, such as, e.g., a water-cooling jacket, is attached to each divided member 11a and 11a of the forming die 11. In Fig. 1, each of the arrows 41 and 42 shows the flow direction of cooling water (i.e. , temperature controlling liquid) as cooling fluid passing through the liquid cooling jacket. In the present invention, in place of the cooling water, cooling oil can be used as the cooling fluid.

The forming die temperature adjusting device 40 controls the temperature of the forming die 11 so as to fall within the temperature range of 5 to 120 ⁰C, more preferably 20 to 70 ⁰C.

Each guide 20 has an insertion hole 21 for holding the corresponding diameter expansion scheduled portion 2 of the raw material 1 in a buckling preventing state. This insertion hole 21 is penetrated through the guide 20 and extended in the axial direction of the guide 20. The insertion hole 21 is formed to have the same cross-sectional shape as that of the diameter expansion scheduled portion 2 of the raw material 1, and is capable of fitting the raw material 1 in an axially slidable manner. The diameter expansion scheduled portion 2 of the raw material 1 is held in a buckling preventing state by inserting the raw material 1 in the insertion hole 21 and disposing the diameter expansion scheduled portion 2 of the raw material 1 in the insertion hole 21.

The tip end portion of each guide 20 is formed to be smaller than the rear end portion of this guide 20. At the rear end portion (i.e., the central portion of the rear end face) of the guide 20, an inlet portion 21a of the insertion hole 21 for inserting the raw material 1 into the insertion hole 21 is formed. On the other hand, at the tip end portion (i.e., the central portion of the tip end face) of the guide 20, an outlet portion 21b of the insertion hole 21 for the raw material 1 for coming out of the insertion hole 21 is formed.

Each guide heating device 50 is provided for heating each guide 20. In this embodiment , as the guide heating device 50 , a bar-shaped electric heating element (electric heater) is mounted in the guide 20. Each guide heating device 50 is provided to heat each guide 20 to the temperature range of 170 to 500 "C, more preferably 200 to 350 ⁰C.

Eachpunch 30 pressurizes the corresponding diameter expansion scheduled portion 2 of the raw material 1 in the axial direction thereof. Both the punches 30 and 30 are disposed at both axial ends of the raw material 1 in an opposed manner.

Each punch driving apparatus 35 is configured to move the corresponding punch 30 in the axial direction of the raw material 1, and connected to the corresponding punch 30. The operation of the punch driving apparatus 35 causes the movement of the punch 30 to thereby axially pressurize the diameter expansion scheduled portion 2 of the rawmaterial 1 with the punch 30. In this embodiment , a fluid pressure cylinder, such as, e.g., an oil pressure, or a gas-pressure cylinder, is used as the punch driving apparatus 35.

Each guide driving apparatus 25 is configured to move each guide 20 in a direction 27 opposite to the moving direction 37 of the corresponding punch 30 (i.e., the direction of pressurizing the raw material diameter expansion scheduled portion 2 with the punch 30) (see Fig. 6B). In this embodiment, a fluid pressure cylinder, such as, e.g., a hydraulic cylinder or a gas-pressure cylinder, as the guide driving apparatus 25 is connected to the guide 20 via a connecting member 26. In Fig. 1, for an easy understanding of the structure of the guide 20, the guide driving apparatuses 25 and the connecting members 26 are not illustrated.

The raw material insertion apparatus 60 is configured to slidably insert the raw material 1 into the insertion hole 21 of one of the guides 20 from the insertion hole inlet portion 21a of the rear end portion of the guide 20. This raw material insertion apparatus 60 has a raw material loading base 61 for disposing the raw material 1 in a heated state, and a raw material pushing device 62 for pushing the raw material 1 disposed on the raw material loading base 61 into the insertionhole 21 of the guide 20. In this embodiment , a rodless cylinder is used as the raw material pushing device 62. The reference numeral "63" denotes a pushing portion of the raw material pushing device 62. This pushing portion 63 is slidably moved along the linear guide of the raw material pushing device 62.

One of the punch driving apparatuses 35 and 35 and the raw material insertion apparatus 60 are installed on a common movable stage 80 movable in the horizontal direction (i.e., backward and forward) . By moving the movable stage 80 with the movable stage driving device 81, the raw material insertion apparatus 60 can be moved to the position of the insertion hole inlet portion 21a of the rear end portion of the guide 20, or the punch 30 of the punch driving apparatus 35 can be moved to the position of the insertion hole inlet portion 21a of the rear end portion of the guide 20. In this embodiment, a fluid pressure cylinder, such as, e.g., a hydraulic cylinder or a gas-pressure cylinder, as the movable stage driving device 81, is connected to the movable stage 80.

The raw material heating device 70 is used to heat the raw material 1. In this embodiment, as the raw material heating device 70, a heating furnace, such as, e.g. , an electric furnace, is placed near the raw material insertion apparatus 60.

The raw material heating device 70 is configured to heat the raw material 1 to the temperature range of 400 to 570 "C, more preferably 430 to 560 °C, still more preferably 510 to 560 "C.

Next, an embodiment of an upsetting method using the aforementioned upsetting apparatus 10 will be explained below.

Initially, the entire raw material 1 is heated in advance to the solution heat treatment temperature of this raw material 1 with the raw material heating device 70. In this embodiment, since this raw material 1 is made of heat-treatment type aluminum alloy, the raw material 1 is heated in advance to the temperature range of 400 to 570 °C, preferably 430 to 560 ¹C, more preferably 510 to 560 ⁰C, as the solution heat treatment temperature. Heating the raw material 1 to this temperature range results in decreased deformation resistance of the diameter expansion scheduled portion 2 of the raw material 1 and enables assured solution heat treatment of the raw material 1. Consequently, the quench hardening effect of the rawmaterial 1 can be assuredly demonstrated, and the upsetting manufactured product 5 can be assuredly increased in strength.

In the present invention, the heating temperature of the raw material 1 by the raw material heating device 70 is suitably set in accordance with the type of the material of the raw material 1. For example, in cases where the raw material 1 is made of heat-treatment type aluminum alloy, the heating temperature range of the raw material 1 preferably falls within the range of 400 to 570 ⁰C, more preferably 430 to 560 "C, still more preferably 510 to 560 ⁰C. In more detail, in cases where the raw material 1 is made of 2xxx series heat-treatment type aluminum alloy, the heating temperature range of the raw material 1 preferably falls within the range of 450 to 570 °C, more preferably 490 to 540 °C. In cases where the raw material 1 is made of 6xxx series heat-treatment type aluminum alloy, the heating temperature range of the raw material 1 preferably falls within the range of 500 to 570 ° C, more preferably 510 to 560 ⁰C. In cases where the raw material 1 is made of 7xxx series heat-treated type aluminum alloy, the heating temperature range of the raw material 1 preferably falls within the range of 430 to 510 ⁰C, more preferably 450 to 500 ¹C.

Both the divided members 11a and 11a of the forming die 11 are set so as to be separated slightly (for example, several mm). Moreover, both the divided members 11a and 11a of the forming die 11 are adjusted (cooled) in temperature beforehand with the forming die temperature adjusting device 40 so that the temperature of the divided members 11a and 11a heated by the raw material heating device 70 falls within the range of 5 to 120 ⁰C, more preferably 20 to 70 ⁰C below the temperature of the raw material 1 in the heated state. By adjusting the temperature of both the divided members 11a and 11a so as to fall within this temperature range, the quench hardening effect can be further assuredly demonstrated, resulting in an upsetting manufactured product 5 further increased in intensity.

Furthermore, both the guides 20 and 20 are heated in advance to the temperature range of 170 to 500⁰C, more preferably 200 to 350 ° C by the guide heating devices 50 and 50. By heating both the guides 20 and 20 to this temperature range, the raw material 1 in a heated state can be maintained in a high temperature state until immediately before the upsetting, and also can equalize the temperature of this raw material 1.

If both the guides 20 and 20 are not heated, the following problem arises . Namely, if the diameter expansion scheduled portion 2 of the raw material 1 is placed in the insertion hole 21 of the guide 20 in a non-heated state, the diameter expansion scheduled portion 2 falls in temperature when the diameter expansion scheduled portion 2 is brought into contact with the peripheral surface of the insertion hole 21. Consequently, the deformation resistance of the diameter expansion scheduled portion 2 increases, which make it difficult to expand the diameter expansion scheduled portion 2. in order to avoid this problem, it is necessary to heat both the guides 20 and 20.

In addition to the above, the raw material insertion apparatus 60 is moved in advance to the position of the insertion hole inlet portion 21a of the rear end portion of the guide 20 with the movable stage driving device 81.

Subsequently, as shown in Fig.2, the raw material 1 in a heated state is taken out from the rawmaterial heating device 70 and disposed on the raw material loading base 61 of the raw material insertion apparatus 60.

Then, by pushing this raw material 1 in the axial direction of this raw material 1 by the raw material pushing device 62 of the raw material insertion apparatus 60, as shown in Fig. 3, this raw material 1 is slidably inserted into the insertion hole 21 of one of the guides 20 and 20 from the insertion hole inlet portion 21a of the rear end portion of the guide 20.

Thereafter, the movable stage 80 is moved with the movable stage driving device 81 to thereby move the punch 30 and the punch driving apparatus 35 to the position of the insertion hole inlet portion 21a of the rear end portion of the guide 20.

Subsequently, as shown in Fig. 4, the punch 30 is moved with the punch driving apparatus 35 to push the raw material 1 so that each diameter expansion scheduled portion 2 and 2 of the raw material

1 are placed in the corresponding insertion holes 21 and 21 of the guides 20 and 20 in a heated state.

Subsequently, as shown in Fig.5A and Fig.5B, both the divided members 11a and lla of the forming die 11 are approached mutually with the forming die driving devices 17 and 17 to thereby clamp the non-diameter-expansion scheduled portion 3 of the raw material 1 between the divided grooves of the insertion hole 14 of both the divided members lla and lla. Thus, the non-diameter-expansion scheduled portion 3 of the raw material 1 is secured to the securing portion 13 of the forming die 11 in a state in which the non-diameter-expansion scheduled portion 3 is fitted in the insertion hole 14 formed by the integration of the divided grooves of the divided members lla and lla. At the same time, at least the tip end portion of each guide 20 is placed in the corresponding cavity 12 of the forming die 11.

Through the above procedures , the raw material 1 is set to the forming die 11 and the both the guides 20 and 20.

In this state, as shown in Fig.6A and Fig.6B, both the punches 30 and 30 are simultaneouslymoved by both the punch driving apparatus 35 and 35 to simultaneously axially pressurize each diameter expansion scheduled portion 2 of the raw material 1 with the . corresponding punch 30. At the same time, each guide 20 is moved in a direction 27 opposite to the moving direction 37 of the corresponding punch 30 with both the guide driving apparatuses 25 and 25. Thereby, both the diameter expansion scheduled portions 2 and 2 of the raw material 1 exposed between the tip end portion of each guide 20 and 20 and the securing portion 13 of the forming die 11 are simultaneously expanded in diameter within the cavities 12 and 12 of the forming die 11.

In this embodiment , simultaneously with or immediately after the fixing of the raw material 1 to the securing portion 13 of the forming die 11, each diameter expansion scheduled portion 2 and

2 of the raw material 1 is pressurized with the corresponding punch

30.

In the present invention, it is preferable to perform the pressurization of each diameter expansion scheduled portion 2 and 2 of the raw material 1 as quickly as possible in a short time period simultaneously with or immediately after the securing the raw material 1 to the securing portion 13 of the forming die 11. Concretely, it is preferable to execute the pressurization within 30 seconds, more preferably within 13 seconds, after the securing of the raw material 1. The reason is as follows . When the raw material 1 is secured to the securing portion 13 of the forming die 11, the non-diameter-expansion scheduled portion 3 of the raw material 1 will be partially cooled due to the contact with the securing portion 13 of the forming die 11. Consequently, the non-diameter-expansion scheduled portion 3 of the raw material 1 falls in temperature than the diameter expansion scheduled portions 2 and 2, causing temperature variation of the raw material 1. This in turn causes insufficient quench hardening of the raw material 1. In order to solve this problem, in this embodiment, the raw material 1 is pressurized simultaneously with or immediately after the securing of the raw material 1 to the securing portion 13 of the forming die 11. As a result , the raw material 1 can be maintained in temperature uniformly, which in turn can assuredly increase the strength of the upsetting manufactured product 5. When each of the diameter expansion scheduled portions 2 and 2 of the raw material 1 is expanded in diameter, diameter expanded portions 6 and 6 each having an approximately circular-shape 6 are formed at the axial end portions of the raw material 1 as shown in Fig. 9.

In the present invention, the traveling speed of the punch 30 and the traveling speed of the guide 20 are set depending on the diameter expansion designed shape of each diameter expansion scheduled portion 2 of the rawmaterial 1. Moreover, these traveling speeds can be constant or fluctuated.

The diameter expansion scheduled portion 2 of the raw material 1 is gradually expanded in the cavity 12 in accordance with the movements of the punch 30 and the guide 20. In accordance with the expansion of the diameter expansion scheduled portion 2, the contact-surface area of the diameter expansion scheduled portion 2 and the peripheral surface of the cavity 12 increases gradually. Therefore, the diameter expanded portion 6 is cooled quickly while the diameter expansion scheduled portion 2 being expanded in diameter.

As shown in Fig. 7A and Fig. 7B, when each diameter expansion scheduled portion 2 and 2 of the raw material 1 is expanded in the corresponding cavity 12 into a prescribed shape (i.e. , approximately circular disc shape) within the corresponding cavity 12, the movements of both the punches 30 and 30 and both the guides 20 and 20 are terminated.

Subsequently, as shown in Fig. 8, both the divided members

11a and 11a of the forming die 11 are detached with the forming die driving devices 17 and 17. Then, the raw material 1 is taken out of the forming die 11 to thereby obtain the upsetting manufactured product 5 shown in Fig. 9.

Subsequently, the punches 30 and 30, the guides 20 and 20, the movable stage 80, etc. , are returned to the respective initial position shown in Fig.2. Thereafter, upsetting of a new rawmaterial 1 is performed in the same procedures mentioned above. In this embodiment, the obtained upsetting manufactured product 5 is subjected to aging treatment, such as, e.g., artificial-aging treatment or natural-aging treatment, as heat treatment after the upsetting. This enables to obtain an upsetting manufactured product 5 further increased in intensity.

The conditions of this aging treatment are suitably set depending on the type of the material of the raw material 1, and the aging treatment is executed to the raw material 1 under the conventional conditions. For example, in cases where the raw material 1 is made of 6xxx series heat-treatment type aluminum alloy, as the conditions for the aging treatment , it is preferable to execute the aging treatment at the aging temperature of 150 to 210⁰C, more preferably 160 to 190 ⁰C for 5 to 10 hours, more preferably 7 to 9 hours as the retention time of the aging temperature.

According to the upsetting method of the embodiment, the raw material 1 and the guides 20 are heated at the time of expanding the diameter expansion scheduled portion 2 of the raw material 1, and the forming die 11 is adjusted in temperature so as to be below the heating temperature of the raw material 1. Therefore, non- diameter-expansion scheduled portion 3 of the raw material 1 is cooled and quenched by the contact with the peripheral surface of the securing portion 13 of the forming die 11, and each diameter expansion scheduled portion 2 of the raw material 1 is cooled and quenched by the contact with the peripheral surface of the cavity 12 while being expanded. Therefore, the diameter expanded portion 6 can be quenched while expanding the diameter expansion scheduled portion 2 of the raw material 1. That is, the diameter expansion of the diameter expansion scheduledportion 2 and the quenchhardening of the diameter expanded portion 6 can be performed simultaneously. Therefore, in this upsetting method, there is an advantage that it is not necessary to perform a quench hardening step separately. Furthermore, at the time of quench hardening, the raw material 1 is secured to the securing portion 13 of the forming die 11 and the diameter expansion scheduled portion 2 of this raw material

I is placed in the cavity 12 in the expanded state within the cavity 12. Therefore, possible quench distortion which may occur at the time of quench hardening can be prevented. This enables elimination of a correction step for correcting quench distortion, resulting in a reduced manufacturing cost .

Furthermore, since the raw material 1 in a heated state is inserted into the insertion hole 21 of one of the guides 20 and 20 from the insertion hole inlet portion 21a of the rear end portion of the guide 20, the raw material 1 can be set to the forming die

II and both the guides 20 and 20 while maintaining the raw material 1 in a high temperature maintained state. Therefore, it becomes possible to prevent a drawback that the raw material 1 falls in temperature before the upsetting to cause a portion with inadequate quench hardening, which in turn can assuredly attain the high intensity of the upsetting manufactured product 5.

Furthermore, by axially pressurizing the diameter expansion scheduled portion 2 of the raw material 1 with the punch 30 simultaneous with or immediately after the securing of the raw material 1 to the securing portion 13 of the forming die 11, the temperature of the raw material 1 can be maintained uniformly until immediately before the upsetting. Therefore, the intensity of he upsetting manufactured product 5 can be assuredly further increased .

Furthermore, the raw material 1 can be firmly secured to the securing portion 13 of the forming die 11 by clamping the non-diameter-expansion scheduled portion 3 of the raw material 1 between the divided grooves of the insertion holes 14 of both the divided members 11a and 11a of the forming die 11. Furthermore, quench distortion can be prevented assuredly. Furthermore, since the raw material 1 is quickly brought into contact with the forming die 11 at the time of securing the raw material 1, the raw material 1 can be quickly cooled, which further enhances the quench hardening effect.

Furthermore, solution heat treatment can be assuredly performed to the raw material 1 by heating the raw material 1 to a prescribed temperature range as solution heat treatment temperature of the raw material 1. In addition to the above, the quench hardening effect can be demonstrated more assuredly, which makes it possible to increase the intensity of the upsetting manufactured product 5 more assuredly.

Moreover, since both the diameter expansion scheduledportions 2 and 2 of the rawmaterial 1 are expanded in diameter simultaneously, the upsetting manufactured product 5 in which diameter expanded portions 6 and 6 are formed at both axial end portions can be manufactured efficiently.

Although an embodiment of the present invention was explained above, it should be noted that the present invention is not limited to the embodiment, and includes various modifications and changes thereof.

In the present invention, it is also possible to manufacture an upsetting manufactured product 5 as shown in Fig. 12. In this upsetting manufactured product 5, the entire axial end portions of the raw material 1 are expanded into diameter expanded portions 6 and 6.

Needless to say, the present invention is not limited to the case in which the a preform for an arm for vehicles is manufactured, but also can be applied to the case in which a preform for various products, such as, e.g., a connecting rod for vehicles, or a double-headed piston for compressors, is manufactured. Furthermore, in the present invention, a diameter expansion scheduled portion 2 of a raw material 1 can be located at only one portion, such as, e.g., an axial intermediate portion of the raw material 1 or one axial end portion thereof.

Furthermore, in the present invention, the punch 30 can be heated or cooled.

Furthermore, in the present invention, the raw material 1 can be an extruded material, a casting material, a rolled materials, such as, e.g., a continuously cast rolled material manufactured by the Properzi method, or another material manufactured by any other methods .

EXAMPLE

Next , concrete Examples andComparative Examples of the present invention will be shown below. However, it should be noted that the present invention is not limited to the following examples .

As rawmaterials 1 , a plurality of heat-treatment type aluminum alloy extruded materials whose alloy number is 6061 according to JIS (Japanese Industrial Standards) were prepared. The diameter of the raw material 1 was 16 mm. Each raw material 1 was subjected to the upsetting method shown in the aforementioned embodiment. At this time, the heating temperature of the raw material 1, the heating temperature of both the guides 20 and 20, the temperature of the forming die 11, the setting method of the raw material 1, and the heat treatment after the upsetting were variously changed as explained below.

Subsequently, the warpage "a" and the bend "b" of the obtained upsetting manufactured product 5 were measured (see Fig. 1OA and Fig. 10B) . Moreover, as the mechanical strength of the upsetting manufactured product 5, the tensile strength and the 0.2% proof stress of eachof the non-diameter expandedportions 7 andthe diameter expanded portions 6 of the upsetting manufactured products 5 were measured.

In Fig. 1OA, "a" shows the amount of warpage of the upsetting manufactured product 5. In Fig. 1OB, "b" shows the amount of bend of the upsettingmanufacturedproduct 5. Fig.11 shows the extraction position of the test piece Tl for measuring the tensile strength of the non-diameter expanded portion 7 of the upsetting manufactured product 5 and the 0.2% proof stress, and the extraction position of the test piece T2 for measuring the tensile strength and the

0.2% proof stress of the diameter expanded portion 6.

The above test results are shown in Table 1. *-3 σ

(D

J-

O

In Table 1, the mark shown in the column "Setting method of the raw material" and the mark shown in the column of "Heat treatment after the upsetting" denote as follows.

A...The raw material 1 was set to the forming die 11 and both the guides 20 and 20 by inserting the rawmaterial 1 into the insertion hole 21 of one of the guides 20 from the insertion hole inlet portion

21a of the rear end portion of the guide 20. B...The raw material 1 was set to the forming die 11 and both the guides 20 and 20 by directly setting it between the divided members 11a and 11a of the forming die 11 from the side thereof.

<Mark shown in the column of "Heat treatment after the upsetting" > A...The upsetting manufactured product 5 was subjected to the artificial-aging processing under the conditions of 190 ° C x 8 hours after the upsetting.

B...After the upsetting, the upsetting manufactured product 5 was subjected to solution heat treatment under the conditions of 530 ⁰C x 3 hours and solution heat treatment in order, and then the upsetting manufactured product 5 was subjected to artificial aging treatment under the conditions of 190 ⁰C x 8 hours.

In Examples 1 to 8 , the guide 20 was heated and the temperature control of the forming die 11 was performed at the time of the upsetting. In Comparative Examples 1 to 3 , the guide 20 was heated and the temperature control of the forming die 11 was not performed at the time of the upsetting. In Comparative Example 4, the guide 20 was not heated and the temperature control of the forming die 11 was performed at the time of the upsetting.

As shown in Table 1 , in Examples 1 to 8 , each of themwas increased in tensile strength and 0.2% proof stress, and warpage and bend were reduced.

On the other hand, in Comparative Example 1, the non-diameter expanded portion 7 and the diameter expanded portion 6 were low in tensile strength and 0.2% proof stress. In Comparative Example 2, the warpage and the bend were large. In Comparative Example 3, the non-diameter expanded portion 7 and the diameter expandedportion 6 were relatively low in tensile strength and 0.2% proof stress. In Comparative Example 4, the diameter expansion scheduled portion 2 of the raw material 1 could not be expanded in diameter. The reason is as follows . That is , in Comparative Example 4 , since the guide 20 was not heated, when the diameter expansion scheduled portion 2 of the raw material 1 was placed in the insertion hole 21 of the guide 20 , the temperature of the diameter expansion scheduledportion 2 falls in accordance with the contact with the peripheral surface of the insertion hole 21 of the diameter expansion scheduled portion 2. Consequently, the deformation resistance of the diameter expansion scheduled portion 2 increased. It should be understood that the terms and expressions used herein are used for explanation and have no intention to be used to construe in a limited manner, do not eliminate any equivalents of features shown and mentioned herein, and allow various modifications falling within the claimed scope of the present invention.

Industrial Applicability

The present invention can be applied to an upsetting method and an upsetting apparatus for manufacturing various products , such as, e.g., a double-headed piston of an arm, a connecting rod, or a compressor for vehicles (automobiles or railroad vehicles).

While the present invention may be embodied in many different forms, a number of illustrative embodiments are described herein with the understanding that the present disclosure is to be considered as providing examples of the principles of the invention and such examples are not intended to limit the invention to preferred embodiments described herein and/or illustrated herein.

While illustrative embodiments of the invention have been described herein, the present invention is not limited to the various preferred embodiments described herein, but includes any and all embodiments having equivalent elements , modifications, omissions, combinations (e.g., of aspects across various embodiments). adaptations and/or alterations as would be appreciated by those in the art based on the present disclosure. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive. For example, in the present disclosure, the term "preferably" is non-exclusive andmeans "preferably, but not limited to." In this disclosure and during the prosecution of this application, means-plus-function or step-plus-function limitations will only be employed where for a specific claim limitation all of the following conditions are present in that limitation: a) "means for" or "step for" is expressly recited; b) a corresponding function is expressly recited; and c) structure, material or acts that support that structure are not recited. In this disclosure and during the prosecution of this application, the terminology "present invention" or "invention" may be used as a reference to one or more aspect within the present disclosure. The language present invention or invention should not be improperly interpreted as an identification of criticality, should not be improperly interpreted as applying across all aspects or embodiments (i.e., it should be understood that the present invention has a number of aspects and embodiments), and should not be improperly interpreted as limiting the scope of the application or claims. In this disclosure and during the prosecution of this application, the terminology "embodiment" can be used to describe any aspect, feature, process or step, any combination thereof , and/or any portion thereof, etc. In some examples, various embodiments may include overlapping features . In this disclosure and during the prosecution of this case, the following abbreviated terminology may be employed: "e.g. " which means "for example; " and "NB" which means "note well. "

Claims

1. An upsetting method, comprising the steps of: preparing anupsetting apparatus including a forming diehaving a securing portion for securing a bar-shaped raw material and a cavity, a guide having an insertion hole for holding a diameter expansion scheduled portion of the raw material in a buckling preventing state, the insertion hole being penetrated and extended in an axial direction, and a punch; disposing the diameter expansion scheduled portion of the raw material in a heated state in the insertion hole of the guide in a heated state; disposing a tip end portion of the guide in the cavity of the forming die adjusted in temperature so as to be below temperature of the raw material; securing the rawmaterial to the securing portion of the forming die; and while keeping the above state, moving the guide in a direction opposite to amoving direction of the punchwhile axiallypressurizing the diameter expansion scheduled portion of the raw material by moving the punch, to thereby expand the diameter expansion scheduled portion of the raw material exposed between the tip end portion of the guide and the securing portion of the forming die within the cavity of the forming die .

2. The upsetting method as recited in claim 1, wherein the diameter expansion scheduled portion of the raw material is placed in the insertion hole of the guide by inserting the raw material in a heated state into the insertion hole of the guide in a heated state from the insertion hole inlet portion formed at a rear end portion of the guide.

3. The upsetting method as recited in claim 1, wherein the diameter expansion scheduled portion of the raw material is axially pressurized with the punch simultaneous with or immediately after the securing of the raw material to the securing portion of the forming die .

4. The upsetting method as recited in claim 1 , wherein the securing portion of the forming die is provided with a raw material fixing insertion hole communicated with the cavity, wherein the forming die has a plurality of divided members divided by the dividing plane vertically dividing insertion hole and the cavity, and wherein the raw material is secured to the securing portion of the forming die by clamping a non-diameter-expansion scheduled portion of the raw material between divided grooves of the insertion holes of a plurality of divided members of the forming die.

5. The upsetting method as recited in claim 1 , wherein the raw material is heated to solution heat treatment temperature of the raw material .

6. The upsetting method as recited in claim 5 , wherein the raw material is made of heat-treatment type aluminum alloy, and wherein the raw material is heated to a temperature range of 400 to 570 ⁰C.

7. The upsetting method as recited in claim 6, wherein the forming die is adjusted in temperature so as to fall within the temperature range of 5 to 120 "C.

8. The upsetting method as recited in claim 6, wherein the guide is heated to a temperature range of 170 to 500 ⁰C.

9. The upsetting method as recited in claim 1 , wherein the raw material has a non-diameter-expansion scheduled portion as its axial intermediate portion and diameter expansion scheduled portions at its axial both end portions, wherein the upsetting apparatus has two cavities in the forming die, two guides, and two punches, wherein each diameter expansion scheduled portion of the raw material in a heated state is placed in the corresponding insertion hole of the guide in a heated state, wherein the tip end portion of each guide is placed in the cavity of the forming die adjusted in temperature so as to be below the temperature of the raw material. wherein the raw material is secured to the securing portion of the forming die , and wherein, while keeping the aforementioned state, both the diameter expansion scheduled portions of the raw material are simultaneously expanded in diameter by moving each guide in a direction opposite to the moving direction of the corresponding punch while simultaneously axially pressurizing each diameter expansion scheduled portion of the raw material with the corresponding punch.

10. An upsetting manufactured product obtained by the upsetting method as recited in any one of claims 1 to 9.

11. A method of manufacturing an upsetting manufactured product, comprising the steps of: subjecting a raw material to the upsetting method as recited in any one of claims 1 to 9 ; and thereafter subjecting the raw material to aging treatment.

12. An upsetting apparatus, comprising: a forming die having a securing portion for securing a bar-shaped raw material and a cavity,- a guide having an insertion hole for holding a diameter expansion scheduled portion of the raw material in a buckling preventing state, the inserting hole being penetrated and extended in an axial direction; apunch foraxialpressurizing the diameter expansion scheduled portion of the raw material placed in the insertion hole of the guide; a guide driving apparatus for moving the guide in a direction opposite to a moving direction of the punch; a raw material heating device for heating the raw material; a forming die temperature adjusting device for adjusting the forming die so as to be a temperature below a heating temperature of the raw material by the raw material heating device; and a guide heating device for heating the guide.

13. The upsetting apparatus as recited in claim 12, further comprising a raw material insertion apparatus for inserting the raw material into the insertion hole of the guide from the insertion hole inlet portion formed at a rear end portion of the guide.

14. The upsetting apparatus as recited in claim 12, wherein the securing portion of the forming die has a raw material fixing insertion hole communicated with the cavity, and wherein the forming die has a plurality of divided members divided by a dividing plane vertically dividing the insertion hole and the cavity, whereby the raw material is secured to the securing portion by clamping the non-diameter-expansion scheduledportion of the rawmaterial between the divided grooves of the insertion hole of the plurality of divided members .

15. The upsetting apparatus as recited in claim 11, wherein the rawmaterial heating device is configured to heat the rawmaterial to solution heat treatment temperature of the raw material.

16. The upsetting apparatus as recited in claim 15, wherein the raw material is made of heat-treatment type aluminum alloy, and wherein the raw material heating device is configured to heat the raw material to a temperature range of 400 to 570 "C.

17. The upsetting apparatus as recited in claim 16, wherein the forming die temperature adjusting device is configured to adjust the forming die to a temperature range of 5 to 120 °C.

18. The upsetting apparatus as recited in claim 16, wherein the guide heating device is configured to heat the guide to a temperature range of 170 to 500 ⁰C.

19. An upsetting apparatus for expanding axial both end portions of a bar-shaped rawmaterial as diameter expansion scheduled portions, the raw material having an axial intermediate portion as a non-diameter-expansion scheduled portion, the apparatus comprising: a forming die having a securing portion for securing the raw material and two cavities; two guides each having an insertion hole for holding each diameter expansion scheduled portion of the raw material secured to the securing portion of the forming die in a buckling preventing state, the insertion hole being penetrated through the guide and extended in an axial direction; two punches each for axially pressurizing each diameter expansion scheduled portion of the raw material placed in the insertion hole of each guide; two guide driving apparatus each for moving the corresponding guide in a direction opposite to a moving direction of the corresponding punch; a raw material heating device configured to heat the raw material ; aforming die temperature adjusting device configured to adjust the forming die so as to be a temperature below the heating temperature of the raw material by the raw material heating device; and two guide heating devices each configured to heat each guide.

20. The upsetting apparatus as recited in claim 19, further comprising a raw material insertion apparatus for inserting the raw material into the insertion hole of one of guides from the insertion hole inlet portion formed at a rear end portion of the guide .

21. The upsetting apparatus as recited in claim 19, wherein the securing portion of the forming die has a raw material fixing insertion hole communicated with the cavity, and wherein the forming die has a plurality of divided members divided by a dividing plane vertically dividing the insertion hole andboth the cavities , whereby the raw material is secured to the securing portion by clamping the non-diameter-expansion scheduled portion of the raw material between the divided grooves of the insertion holes of the plurality of divided members.

22. The upsetting apparatus as recited in claim 19, wherein the rawmaterial heating device is configured to heat the rawmaterial to solution heat treatment temperature of the raw material.

23. The upsetting apparatus as recited in claim 22, wherein the raw material is made of heat-treatment type aluminum alloy, and wherein the raw material heating device is configured to heat the raw material to a temperature range of 400 to 570 ⁰C.

24. The upsetting apparatus as recited in claim 23, wherein the forming die temperature adjusting device is configured to adjust the forming die to a temperature range of 5 to 120 ⁰C.

25. The upsetting apparatus as recited in claim 23, wherein the guide heating device is configured to heat the guide to a temperature range of 170 to 500 ⁰C.