JP2003154415A - Metal member forming method, metal member, and metal member forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal member forming method, a metal member, and a metal member forming device for achieving the forming property and higher strength of the metal member. SOLUTION: The cylindrical metal member 1 having a hollow chamber 10 and a forming die 3 having a forming die face 31 are used. The metal member 1 is heated to a quench-strengthening temperature zone (e.g. A1 transformation temperature or above). By increasing the internal pressure of the gas in the hollow chamber 10 of the heated metal member 1, a wall 1a of the metal member 1 is swollen (plastically deformed), and the swollen wall 1a of the metal member 1 is brought into close contact with the forming die face 31 of the forming die 3 to perform the forming and the quench-strengthening. The wall 1a of the metal member 1 is hardened, and the strength of the metal member 1 is increased thereby.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal member forming method, a metal member and a metal member forming apparatus capable of improving the formability and strength of a metal member.

[0002]

2. Description of the Related Art A hydroforming method is known as a method for forming a metal member. The hydroforming method uses a tubular metal member having a hollow chamber and a molding die having a molding die surface set to a target shape, and by supplying water to the hollow chamber of the metal member, In this technique, the wall is bulged and deformed, and the bulged and deformed wall of the metal member is brought into close contact with the molding surface of the molding die.

[0003]

According to the above-mentioned hydrofoaming method, the wall of the metal member can be bulged and deformed by supplying water to the hollow chamber of the metal member to form the metal. There is a limit to satisfying both the formability and the high strength of the member.

Particularly, in recent automobile parts and the like, it is required to reduce the thickness of the material in order to reduce the weight, but when the thickness is reduced, the forming force at the time of forming the metal member can be reduced. However, there is a limit to increasing the strength of metal members.

Further, when the material is an iron-based material, it is required to make the material thinner to reduce the weight and to increase the tensile strength (high-tensile steel) by increasing the amount of alloying elements. In the case of high tensile strength, although it is possible to increase the strength of the metal member, the elongation of the material decreases, so the formability of the material decreases and cracks occur when the metal member is bulged and deformed by the hydroform method. Etc. may occur.

The present invention has been made in view of the above circumstances, and provides a metal member forming method, a metal member and a metal member forming apparatus capable of achieving both the formability and the high strength of a metal member. This is an issue.

[0007]

A method for forming a metal member according to the present invention uses a tubular metal member having a hollow chamber and a forming die having a forming die surface to heat to a temperature range where quenching and strengthening are possible. By increasing the internal pressure of the gas in the hollow chamber of the metal member, the wall of the metal member is bulged and deformed, and the bulged and deformed wall of the metal member is brought into close contact with the molding die surface of the molding die for molding. It is characterized by carrying out a forming and quenching strengthening step for quenching and strengthening.

According to the metal member forming method of the present invention,
First, the metal member is heated to a temperature range where quenching and strengthening is possible.
Then, in the forming quenching strengthening step, the wall of the metal member is bulged and deformed by increasing the internal pressure of the gas in the hollow chamber of the metal member. At this time, since gas is contained in the hollow chamber of the metal member, the temperature of the metal member is maintained at a higher temperature than in the case where water is contained in the hollow chamber of the metal member as in the hydroforming method. be able to.

Further, according to the metal member forming method of the present invention, the wall of the metal member which is bulged and deformed as described above is brought into close contact with the forming die surface of the forming die to be formed and is rapidly cooled and strengthened. In this way, when the metal member is bulged and deformed, the metal member is heated to a temperature range where quenching and strengthening is possible, so that the elongation of the metal member can be secured. Therefore, the plastic deformability of the metal member can be improved, and the bulge deformability and the formability of the metal member can be improved.

Further, in the above-described forming quenching and strengthening step, the wall of the metal member that has been bulged and deformed is brought into close contact with the forming die surface of the forming die, whereby the metal member is rapidly quenched and strengthened, and the strength of the metal member is enhanced. You can

Further, according to the present invention, a step of loading a cylindrical metal member having a hollow chamber into a molding die, a step of heating the metal member loaded in the molding die, and an inside of the molding die By supplying gas to the hollow chamber of the metal member heated by, the metal member is plastically deformed, the predetermined surface of the metal member is brought into close contact with the predetermined surface of the molding die, and the metal member is And a step of cooling the metal member by cooling the mold with the metal member inserted into the mold after being plastically deformed. According to the metal member forming method, heating, deformation and cooling of the metal member are continuously performed in the forming die. That is, forming and heat treatment of the metal member are continuously performed, and workability is improved.

Further, according to the present invention, a step of heating a cylindrical metal member having a hollow chamber, a step of loading the heated metal member into a molding die, and a step of loading the heating metal member into the molding die after the heating. Supplying a gas to the hollow chamber of the loaded metal member to plastically deform the metal member and bring a predetermined surface of the metal member into close contact with a predetermined surface of the molding die; A step of cooling the metal member by cooling the metal mold after it is plastically deformed while being inserted into the metal mold, thereby forming the metal member. I will provide a. According to the metal member forming method, the deformation and cooling of the metal member are continuously performed in the forming die. That is, the molding and heat treatment of the metal member are continuously performed.

The metal member of the present invention is characterized by being formed by any one of the metal member forming methods of the present invention. By molding the metal member by any one of the metal member molding methods described above, both moldability and high strength of the metal member can be achieved.

Further, according to the present invention, a mold for loading a tubular metal member having a hollow chamber, and a gas supply means for supplying gas to the hollow chamber of the metal member heated in the mold. And a cooling means for cooling the metal member loaded in the mold by cooling the mold.
A metal member forming apparatus is provided. According to the metal member forming apparatus, the deformation and cooling of the metal member are continuously performed in the forming die. That is, the molding and heat treatment of the metal member are continuously performed.

The metal member forming apparatus of the present invention is characterized by further comprising means for heating the metal member loaded in the forming die. According to the metal member forming apparatus, heating, deformation and cooling of the metal member are continuously performed in the forming die. That is, forming and heat treatment of the metal member are continuously performed, and workability is improved.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A metal member forming method according to the present invention,
According to the metal member and the metal member forming apparatus, at least one of the following embodiments can be adopted.

The metal member as a starting material has a tubular shape having a hollow chamber. A cylindrical shape or a rectangular tube shape can be adopted as the cylindrical shape. The metal member before carrying out the forming quenching strengthening step may have a straight tubular shape or a tubular shape having at least one of a bent portion, a concave portion and a convex portion. The metal member may be an integrally molded product or a product obtained by joining a plurality of materials.

As the material of the metal member, an embodiment which is iron-based (including alloy steel such as high-tensile steel and stainless steel), titanium-based, aluminum-based or copper-based can be adopted. However, it is not limited to these. High-tensile steel means high-tensile steel formed of steel having high tensile strength. As a high-tensile steel, it has a tensile strength of 500 MPa (≈50 kgf / mm) before the forming quenching and strengthening process.
² ) or more iron-based metal, iron-based metal with a tensile strength of 600 MPa or more, iron-based metal with a tensile strength of 800 MPa or more, iron-based metal with a tensile strength of 1000 MPa or more, tensile strength of 1500MP
An iron-based metal having a or more can be used. Generally, high-tensile steel has high strength, but plastic deformability is not always sufficient. According to the method of the present invention and the apparatus of the present invention, since these metal members are heated prior to quenching and strengthening, the plastic deformability of the metal members is improved. Therefore, even if the plastic deformability is not always sufficient as in the case where the material of the metal member is made of high tensile strength, the bulge deformability and the formability of the metal member can be improved. Therefore,
Even if the metal member has a deformed shape, or if the metal member has a large degree of molding, it is possible to ensure good moldability of the metal member.

At least one of the operation of holding the metal member in the furnace chamber of the heating furnace, the induction heating operation of inductively heating the metal member, and the resistance heating operation of energizing the metal member.
Embodiments implemented in seeds may be employed. At least two kinds of each of these operations can be used in combination.
That is, the induction heating operation of inductively heating the metal member can be performed after the operation of holding the metal member in the furnace chamber of the heating furnace. In addition, after performing the operation of holding the metal member in the furnace chamber of the heating furnace, the resistance heating operation of energizing the metal member can be performed. Further, it is possible to perform an induction heating operation of inductively heating the metal member and a resistance heating operation of energizing the metal member without performing an operation of holding the metal member in the furnace chamber of the heating furnace. Induction heating operation to induction heat the metal member,
The resistance heating operation of energizing the metal member can be performed simultaneously with time or with a time shift.

For the operation of holding the metal member in the furnace chamber of the heating furnace, an embodiment can be adopted in which the furnace chamber of the heating furnace is executed in a non-oxidizing atmosphere. As the non-oxidizing atmosphere, at least one of vacuum atmosphere, reducing gas atmosphere, and inert gas atmosphere can be adopted. As the reducing gas atmosphere, at least one of a CO gas atmosphere and a gas atmosphere containing CO can be adopted. As the inert gas atmosphere, a nitrogen gas atmosphere or a rare gas atmosphere such as argon gas can be adopted.

In the induction heating operation of inductively heating a metal member, an alternating current is passed through the conductive member while the conductive member for induction heating is brought close to the metal member facing the molding surface of the molding die. Embodiments implemented by inductively heating the member can be employed. The conductive member for induction heating may have a coil shape or a plate shape as long as the metal member can be induction-heated. The frequency of the alternating current applied to the conductive member for induction heating is
It can be appropriately selected in consideration of the material of the metal member, the equipment cost, the induction heating property, etc. within the frequency range in which the metal member can be induction-heated, and the low frequency frequency region, the medium frequency frequency region, and the high frequency frequency. Areas can be employed as needed. The frequency is, for example, 0.5 kHz
˜5000 kHz, in particular 1 kHz to 2000 kHz can be adopted. However, it is not limited to these frequencies.

When a high frequency alternating current is passed through the conductive member to inductively heat the metal member, the proximity effect of efficiently heating the surface layer of the metal member which is close to the conductive member, and the metal member Since a skin effect in which a current flows through the surface layer can be expected, the surface layer of the metal member can be efficiently heated.

The resistance heating operation for energizing the metal member is performed by energizing the metal member with Joule heat by energizing the metal member with the current terminal connected to the metal member facing the molding surface of the molding die. The embodiment performed by doing so can be adopted. The current supplied from the current-carrying terminal to the metal member may be direct current or alternating current (alternating current). In the case of alternating current, the frequency is selected from low frequency range, medium frequency range, and high frequency range, if necessary, considering the material of metal member, equipment cost, resistance heating property, etc. can do. The frequency is, for example, 0.5 kHz to 5000 kHz, especially 1 kHz.
z to 2000 kHz can be adopted. However, it is not limited to these frequencies. When applying a high frequency alternating current from the energizing terminal to the metal member,
Since a skin effect in which a current flows through the surface layer of the metal member can be expected, the surface layer of the metal member can be efficiently heated.

The metal member is iron-based, and the metal member is A1.
An embodiment in which heating is performed in a temperature range equal to or higher than the transformation point (quenching temperature) can be adopted. The A1 transformation point or higher means a temperature range higher than the austenite formation temperature. In some cases, it is possible to adopt an embodiment in which heating is performed in a temperature range of the A3 transformation point or higher. The upper limit of the heating temperature of the metal member is preferably the liquid phase formation temperature of the base material of the metal member.

In the forming quenching and strengthening step, the wall of the metal member is brought into close contact with the forming die surface of the forming die, whereby at least a part of the metal member can be quenched to promote martensite formation. By quenching in this way, the metal member can be strengthened. Further, in the case of quenching and strengthening, a form in which troostite, sorbite, or the like is generated together with or instead of martensite may be used. Troostite or sorbite is more likely to be produced when the cooling rate is slower than the cooling rate at which martensite is produced.

When the metal member is iron-based, an alloying element having a high quenching multiple can be contained in order to enhance hardenability. Carbon, manganese, silicon, nickel, chromium, and molybdenum are mentioned as alloy elements with a high quenching multiple, and at least one of these alloy elements can be contained. When the metal member is iron-based, the content of at least one of the above-mentioned alloy elements (for example, carbon) is often increased in order to make the material high tensile.

As the molding die, an embodiment provided with a cooling means for cooling the molding die can be adopted. As the cooling means, a cooling passage is formed inside the molding die, a cooling medium such as cooling water or a refrigerant gas is supplied to the cooling passage, and a cooling medium such as cooling water or a refrigerant gas is formed on the molding die surface of the molding die. At least one of the contacting methods can be adopted.
Examples of the material of the molding die include carbon steel, alloy steel, and other metals having good thermal conductivity and good durability.

According to the method of the present invention and the apparatus of the present invention, by increasing the internal pressure of the gas in the hollow chamber of the metal member, the wall of the metal member is bulged and deformed and brought into close contact with the molding surface of the molding die. The operation of increasing the internal pressure of the gas in the hollow chamber of the metal member can employ the embodiment that is executed by supplying the gas to the hollow chamber of the metal member. As the gas supplied to the hollow chamber of the metal member, at least one of air, nitrogen gas, nitrogen-rich gas, argon gas, and argon-rich gas can be adopted. Nitrogen-enriched gas is a gas with a high nitrogen concentration. The argon-rich gas is a gas having a high concentration of argon gas.

As the operation of supplying gas to the hollow chamber of the metal member, an embodiment executed from a high pressure gas supply source capable of supplying high pressure gas can be adopted. The pressure of the high-pressure gas is preferably high considering the formability of the metal member. As the pressure of the high-pressure gas, for example, 10 MPa or more, 15 MPa or more, 20 MPa or more, 30 MPa or more can be set, but in consideration of practicality, 15 to 25 MP
a, 17-23 MPa, 19-21 MPa, 20 MPa
Is preferred. A cylinder, a factory air source, etc. can be illustrated as a high-pressure gas supply source.

An embodiment in which the metal member communicates with the hollow chamber and has an opening formed by an expanded wall surface can be adopted. In this case, adopt an embodiment in which a sealing tool having an inclination corresponding to the inclination of the expanded wall surface of the metal member is applied directly or indirectly to the expanded wall surface of the metal member to seal the opening of the metal member. You can In this case, since the sealing tool is applied to the expansion wall surface forming the opening of the metal member, the expansion wall surface forming the opening of the metal member is well sealed. Therefore, it is advantageous for increasing the pressure in the hollow chamber of the metal member.

The metal member molding method includes the steps of loading (arranging) the metal member in the molding die, heating the metal member loaded in the molding die, and hollowing the metal member heated in the molding die. Supplying metal to the chamber to plastically deform the metal member so that a predetermined surface of the metal member is brought into close contact with a predetermined surface of the mold; and after the metal member is plastically deformed, the metal member is molded. By cooling the mold while it is inserted therein, a step of cooling the metal member can be adopted.

As a method for forming a metal member, a step of heating the metal member, a step of loading (arranging) the heated metal member in a forming die, and a step of heating the metal member in the forming die after heating are performed. A step of plastically deforming the metal member by supplying gas to the hollow chamber and bringing a predetermined surface of the metal member into close contact with a predetermined surface of a molding die; and after the metal member is plastically deformed, the metal member is molded. An embodiment including a step of cooling the metal member by cooling the molding die inserted in the mold can be adopted.

The metal member provided with the desired shape is
It is formed by any one of the above-described metal member forming methods. Any one of the above-described metal member forming methods for forming a metal member into a desired shape
By using the two methods, it becomes possible to achieve both the moldability and the high strength of the metal member.

As the metal member forming apparatus, there is provided a forming die into which a tubular metal member having a hollow chamber is loaded, and gas supply means for supplying gas to the hollow chamber of the metal member heated in the forming die. It is possible to employ an embodiment including a cooling unit that cools the metal member loaded in the mold by cooling the mold. As the gas supply means, the above-mentioned high-pressure gas supply source can be exemplified, and the high-pressure gas supply source has a cylinder, a valve, a supply pipe, and the like.

Further, the metal member forming apparatus including the forming die, the gas supply means and the cooling means may have means for heating the metal member loaded in the forming die. In this case, examples of means for heating the metal member include the above-described induction heating operation and resistance heating operation.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be specifically described below with reference to FIGS. This example is an example in which the quenching strengthening, which is a typical quenching strengthening, is performed on the metal member 1 as the starting material. The metal member 1 used in the forming method according to this embodiment has a cylindrical shape having a hollow chamber 10, and is made of an iron-based metal. The iron-based metal before quenching is made high tensile (high tensile steel),
Specifically, the tensile strength is 600 MPa (≈60 kgf / m
Since it is formed of an iron-based metal of m ² ) or more, plastic deformability is not always sufficient.

According to this embodiment, as shown in FIG. 1, by expanding the both ends of the metal member 1 having a tubular shape, the expanding portion 12 that expands toward the end 12c is formed in advance. Has been done. The expanded wall surface 13, which is the inner wall surface of the expanded portion 12, forms an opening 13x communicating with the hollow chamber 10.

First, in the heating step, the metal member 1 is heated in the heating furnace 2
The metal member 1 is heated in the furnace chamber 20 for a predetermined time and heated to a temperature range in which quenching and strengthening can be achieved, that is, a temperature range not lower than the A1 transformation point. In this case, the metal member 1 can be heated to a temperature range of the A3 transformation point or higher, if necessary. As a result, the whole or part of the structure of the metal member 1 is austenitized. Since the furnace chamber 20 of the heating furnace 2 is maintained in a non-oxidizing atmosphere, oxidation and decarburization of the metal member 1 during heating are suppressed. As the non-oxidizing atmosphere, a vacuum atmosphere, a reducing gas atmosphere, an atmosphere of an inert gas such as argon gas, or the like can be adopted as necessary.

Next, the metal member 1 heated to the target temperature region as described above is taken out from the heating furnace 2, and the metal member 1 is placed (loaded) in the molding die 3 as shown in FIG. The molding die 3 is formed of a steel-based material that is a typical metal material, and has a molding die surface 31 set to a target shape. In this case, the metal member 1 is configured so that the strengthening request portion of the wall 1a of the metal member 1 does not come into contact with the molding surface 31 of the molding die 3.
Is preferably arranged. Inside the mold 3, a cooling passage 33 through which a cooling medium such as cooling water or a refrigerant gas flows is formed as a cooling means. When a cooling medium such as cooling water or a refrigerant gas flows into the cooling passage 33, the mold 3 is cooled,
The metal member 1 which is the object to be molded can be rapidly cooled on the molding die surface 31 of the molding die 3. In addition, before or during the heating step described above, a cooling medium such as cooling water or a refrigerant gas is caused to flow into the cooling passage 33 of the molding die 3 to form the molding die 3.
Is preferably cooled.

In the forming quenching and strengthening step according to this embodiment, as shown in FIG. 2, the expanded wall surface 1 of the expanded portion 12 of the metal member 1
A set of two sealing members 40, 41 having a sealing surface 44 with an inclination corresponding to the inclination of 3 is used. Seal tool 4
0 and 41 can be formed of metal or refractory.
One of the seal members 40 has a passage 40a connected to the high pressure gas supply source 5 as a gas supply means. The other sealing member 41 has a sealing function, but is not connected to the high-pressure gas supply source 5. The high-pressure gas supply source 5 supplies a high-pressure gas, a cylinder 50 in which the high-pressure gas is sealed, a valve 52 having an opening / closing valve 51 for opening and closing the cylinder 50, and a pressure of the gas sealed in the cylinder 50. It has a pressure gauge 53 that functions as a pressure detection unit that detects the pressure, and a flexible supply pipe 54 that functions as a supply passage led from the valve 52.

Then, as shown in FIG.
41 is fitted into the openings 13x at both ends of the metal member 1, and the sealing surface 44 is applied to the expansion wall surface 13 of the expansion portion 12 of the metal member 1 directly or indirectly through an intermediate member (not shown) for sealing. . In this case, the space W is interposed between the wall 1 a of the metal member 1 and the molding die surface 31.

In the forming quenching and strengthening step according to this embodiment, the high pressure of the high pressure gas supply source 5 is obtained in the state where the sealing members 40 and 41 are sealed to the expanding wall surface 13 of the expanding portion 12 of the metal member 1 as described above. A gas (for example, 20 MPa) is supplied to the hollow chamber 10 of the metal member 1. Specifically, the high pressure gas supply source 5
By opening the on-off valve 51, the high-pressure gas in the cylinder 50 of the high-pressure gas supply source 5 is passed through the supply pipe 54 and the passage 40a of the one seal member 40, and the hollow chamber 10 of the metal member 1 is opened.
Supply to.

As a result, the internal pressure of the gas in the hollow chamber 10 of the metal member 1 is increased, and the wall 1a of the metal member 1 is bulged and deformed (plastically deformed) outward in the radial direction of the wall 1a, whereby the molding surface of the molding die 3 is formed. Three
Close to 1. As shown in FIG. 3, the wall 1 a of the metal member 1 is thereby molded along the molding surface 31. Further, simultaneously with the molding, the wall 1a of the metal member 1 is rapidly cooled by the molding die surface 31 of the molding die 3, so that the wall 1a of the metal member 1 is quenched.

Immediately before or during the forming quenching and strengthening step according to the present embodiment, a cooling medium such as cooling water or a refrigerant gas is caused to flow through the cooling passage 33 of the forming die 3 in order to enhance hardenability. Is preferably cooled.

As the gas to be supplied to the hollow chamber 10 of the metal member 1, at least one selected from air, nitrogen gas, nitrogen-enriched gas, argon gas, and argon-enriched gas can be adopted as required. In consideration of cost reduction, air can be adopted. Considering the suppression of oxidation of the metal member 1, it is possible to employ nitrogen gas, nitrogen-enriched gas, argon gas, or argon-enriched gas that has low or no oxidation ability. When the molding and quenching of the metal member 1 are completed as described above, the metal member 1 and the sealing members 40 and 41 are separated, and the metal member 1 having a desired shape is removed from the molding die 3. Separate.

As described above, according to this embodiment, since the metal member 1 is heated to a high temperature region during the bulging deformation, the material forming the metal member 1 is made of a high-tensile metal material. Even though the plastic deformability is lowered due to the above, the plastic deformability of the metal member 1 can be improved. For this reason, the bulging deformability of the metal member 1 and by extension, the formability can be improved.

Further, according to the present embodiment, in the forming quenching strengthening step, the wall 1a of the metal member 1 which is bulged and deformed is brought into close contact with the forming die surface 31 of the forming die 3 so that the wall 1a of the metal member 1 is removed. The wall 1a of the metal member 1 can be quenched by quenching heat. Thereby, the wall 1a of the metal member 1 can be strengthened. That is, as described above, according to this embodiment, both the formability and the high strength of the wall 1a of the metal member 1 can be achieved at the same time.

According to the present embodiment in which the metal member 1 can be strengthened in this way, the tensile strength before quenching is 600 MPa (≈
Although the metal member 1 made of an iron-based metal of 60 kgf / mm ² ) or more is used, the iron-based metal forming the metal member 1 has a tensile strength of 1 by the above-mentioned quenching.
000 MPa (≈100 kgf / mm ² ) or more or 1
It can be strengthened to 200 MPa or more, and in some cases 1500 MPa or more.

According to this embodiment, as described above, in the forming and quenching strengthening step, the wall 1a of the metal member 1 which is bulged and deformed.
The wall 1a of the metal member 1 is hardened and strengthened by closely contacting with the molding surface 31 of the molding die 3. Therefore, the heating temperature of the metal member 1 in the heating step, the molding die 3
By appropriately adjusting the cooling capacity of the molding surface 31 of the metal member 1
Forming surface 31 of the forming die 3 in the thickness direction of the wall 1a of
The cooling rate of the one surface layer 1c (outer surface layer) that is in close contact with and can be made faster than the cooling rate of the other surface layer 1d (inner surface layer) facing the molding die surface 31 of the molding die 3.

In other words, in the thickness direction of the wall 1a of the metal member 1, the cooling speed of the one surface layer 1c (outer surface layer) facing and closely contacting the molding surface 31 of the molding die 3 is lower than that of the molding die 3. The cooling rate of the other surface layer 1d (inner surface layer) facing the molding surface 31 can be slowed down. Therefore, in the thickness direction of the wall 1a of the metal member 1, the hardenability of the one surface layer 1c (outer surface layer) facing and closely adhering to the molding die surface 31 of the molding die 3 is enhanced to enhance the strength of this portion. At the same time, it is possible to suppress the hardenability of the other surface layer 1d (inner surface layer) facing the molding surface 31 of the molding die 3 and to secure the toughness of this portion.
That is, the degree of quench hardening can be changed in the thickness direction of the wall 1a of the metal member 1, and the effect of enhancing both strength and impact resistance of the metal member 1 can be expected.

In addition, according to the present embodiment, the sealing members 40, 41 having the sealing surface 44 having the inclination corresponding to the inclination of the expansion wall surface 13 of the expansion portion 12 of the metal member 1 are used. , 41 to the expanded wall surface 1 of the expanded portion 12 of the metal member 1.
Since the opening 13x of the metal member 1 is sealed by pressing the metal member 3 against the metal member 1, good sealing performance can be ensured in the boundary region between the metal member 1 and the seal members 40 and 41, and the hollow chamber 10 of the metal member 1 can be secured. It is possible to effectively achieve high pressure and to enhance the bulging deformability of the wall 1a of the metal member 1.

According to this embodiment, after quenching,
If the expanded portions 12 at both ends of the metal member 1 are unnecessary, the expanded portions 12 may be removed by cutting, or the expanded portions 12 may be left if necessary.

(Second Embodiment) A second embodiment of the present invention will be specifically described below with reference to FIGS. 4 and 5. This embodiment has basically the same configuration as the first embodiment,
Basically, the same effect is obtained. Hereinafter, description will be made focusing on the parts different from the first embodiment. Similar to the first embodiment, the present embodiment is an example in which quenching strengthening, which is a typical quenching strengthening, is performed on the metal member 1. The metal member 1 according to this embodiment has a tubular shape having a hollow chamber 10 and is made of a hardenable iron-based metal. Iron-based metals have been made high tensile strength (high-tensile steel) for high strength, and plastic deformability is not always sufficient.

First, in the heating step, the molding die surface 3 of the molding die 3 is
1 so that the wall 1a of the metal member 1 faces the metal member 1
Are placed (loaded) in the mold 3. In this case, the mold 3
It is preferable to dispose the metal member 1 so that the strengthening portion of the wall 1a of the metal member 1 does not come into contact with the molding die surface 31.
Then, as shown in FIG. 4, a coil-shaped conductive member 6 for induction heating is arranged in the hollow chamber 10 of the metal member 1. That is,
The conductive member 6 for induction heating is brought close to the metal member 1 facing the molding surface 31 of the molding die 3. In this heating step, it is preferable that the mold 3 and the metal member 1 are not in contact with each other in order to prevent the temperature of the mold 3 from rising and prevent the temperature of the metal member 1 from decreasing.

With the conductive member 6 for induction heating placed close to the hollow chamber 10 of the metal member 1 as described above, a high-frequency alternating current is applied to the conductive member 6 to heat the metal member 1 by induction heating. To do. The alternating current supplied to the conductive member 6 has a frequency and a current value capable of inductively heating the strengthening request portion of the wall 1a of the metal member 1 to a temperature range of A1 transformation point or higher or A3 transformation point or higher. In this way, when the high frequency alternating current is applied to the conductive member 6 to inductively heat the wall 1a of the metal member 1, the surface layer of the wall 1a of the metal member 1 which is close to the conductive member 6 is efficiently heated. Since a possible proximity effect and a skin effect in which a current flows through the surface of the metal member 1 can be expected, the surface of the wall 1a of the metal member 1 can be efficiently heated. As a result of such induction heating, the whole or part of the structure of the metal member 1 is austenitized in a short time.

According to the present embodiment, in order to suppress the temperature rise of the molding die surface 31 of the molding die 3 in the heating step of inductively heating the metal member 1, if necessary, as shown in FIG. The heat transfer blocking member 9 can be arranged between the molding die surface 31 and the metal member 1. As the heat transfer blocking member 9,
Those having high heat insulation and high magnetic flux blocking properties are preferable. In addition, before the above heating step or in the middle of the heating step, a cooling medium such as cooling water or a refrigerant gas is added to the molding die 3
It is preferable that the molding die 3 is cooled by flowing it through the cooling passage 33.

Next, when the heating step is completed, if the heat transfer blocking member 9 is used, the heat transfer blocking member 9 is removed from the mold 3. After completing the heating process described above, a forming quenching strengthening process is performed. That is, the molding die surface 31 of the molding die 3 is brought closer to the metal member 1. In this case, as shown in FIG. 5, a space W is interposed between the wall 1a of the metal member 1 and the molding die surface 31. Further, as in the case of the first embodiment, as shown in FIG. 5, seal members 40, 41 having an inclination corresponding to the inclination of the expanded wall surface 13 of the metal member 1 are used.
41 is applied to the expanded wall surface 13 of the metal member 1 directly or indirectly via an intermediate member for sealing.

In this way, the high-pressure gas of the cylinder 50 of the high-pressure gas supply source 5 is opened by opening the opening / closing valve 51 in the state where the sealing members 40 and 41 are sealed to the expansion wall surface 13 of the expansion portion 12 of the metal member 1. The gas is supplied to the hollow chamber 10 of the metal member 1 through the supply pipe 54 and the passage 40a of the seal member 40.
As a result, the internal pressure of the gas in the hollow chamber 10 of the metal member 1 is increased, and the wall 1a of the metal member 1 is bulged and deformed (plastically deformed) outward in the radial direction of the wall 1a, and the wall 1a is brought into close contact with the molding die surface 31 of the molding die 3. Let As a result, the wall 1a of the metal member 1 is molded along the molding surface 31 of the molding die 3, and the molding rapid cooling strengthening step is performed.

In order to enhance hardenability immediately before or during the forming quenching strengthening step according to this embodiment,
Cooling medium such as cooling water or refrigerant gas is passed through the cooling passage 3 of the molding die 3.
It is preferable that the mold 3 is cooled by pouring it into the mold 3.

As described above, according to this embodiment, as in the case of the first embodiment, the metal member 1 is made high tensile steel (high tensile steel), and the plastic deformability is not always sufficient. Even if the metal member 1 is formed of a system metal, since the metal member 1 is heated to a high temperature region during the bulging deformation, the plastic deformability of the metal member 1 is improved, and the bulging deformability of the metal member 1 is increased. As a result, moldability can be improved.

Further, according to this embodiment, in the forming quenching strengthening step, the wall 1a of the metal member 1 induction-heated to the quenching temperature or higher is used.
By bulging and deforming the metal and bringing it into close contact with the molding die surface 31 of the molding die 3, the wall 1a of the metal member 1 is quenched, and thereby the metal member 1 can be strengthened. Therefore, according to this embodiment, as in the case of the first embodiment, both the formability and the increase in strength of the wall 1a of the metal member 1 can be achieved at the same time.

Furthermore, according to the present embodiment, the conductive member 6 for induction heating is brought close to the wall 1a of the metal member 1 facing the molding surface 31 of the molding die 3, and the conductive member 6 is subjected to high-frequency alternation. The metal member 1 is induction-heated by passing an electric current. Therefore, the on-off valve 51 is opened immediately after the wall 1a of the metal member 1 is heated to the target temperature region, and the high-pressure gas in the cylinder 50 of the high-pressure gas supply source 5 is supplied to the hollow chamber 10 of the metal member 1. The wall 1a of the member 1 can be bulged and deformed to be molded.
Therefore, the metal member 1 heated in the target temperature region is heated by the heating furnace 2
It is possible to eliminate the step of taking out from the mold and transporting it to the molding die 3, and it is possible to suppress the temperature decrease of the metal member 1. Therefore, the temperature of the wall 1a of the metal member 1 can be maintained as high as possible immediately before the metal member 1 is molded and immediately before quenching, and both the molding and the quenching of the metal member 1 can be favorably performed. .

Further, according to this embodiment, the wall 1 of the metal member 1 is
When a touches the molding surface 31 of the molding die 3, the molding die 3
Quenching can be strengthened by the molding surface 31.

According to the present embodiment, after performing the heating step of heating the metal member 1, the sealing members 40 and 41 are applied to the expanded wall surface 13 of the metal member 1 to perform sealing. Not limited to this, the sealing members 40 and 41 may be applied to the expanded wall surface 13 of the metal member 1 during the heating process of heating the metal member 1 or before the heating process.

(Third Embodiment) The third embodiment of the present invention will be specifically described below with reference to FIGS. 6 and 7. This embodiment has basically the same configuration as the second embodiment,
Basically, the same effect is obtained. Hereinafter, the description will be focused on the parts that are different from the second embodiment. In the heating process,
The metal member 1 is placed (loaded) in the molding die 3 such that the wall 1a of the metal member 1 faces the molding die surface 31 of the molding die 3. In this case, it is preferable to dispose the metal member 1 so that the strengthening request portion of the metal member 1 does not come into contact with the molding die surface 31 of the molding die 3.

Then, the metal member 1 is set to A by resistance heating operation.
It is heated to a temperature range of 1 transformation point or higher or A3 transformation point or higher. That is, as shown in FIG. 6, the molding die surface 31 of the molding die 3 is formed.
The energizing terminal 7 is connected to the widened portion 12 which is the end of the metal member 1 facing the metal member 1 in this state.
Is energized to heat the wall 1a of the metal member 1 by Joule heat to a temperature range above the A1 transformation point or above the A3 transformation point. The current-carrying terminal 7 can be formed of a metal having good conductivity such as copper, aluminum, titanium, iron, or the like. The current flowing from the current-carrying terminal 7 to the metal member 1 may be direct current or alternating current (alternating current).

When the current flowing from the current-carrying terminal 7 to the metal member 1 is an alternating current, it is possible to adopt a low frequency region, a medium frequency region, or a high frequency region as the frequency. . When a high-frequency alternating current is passed from the energizing terminal 7 to the metal member 1, the metal member 1
Since a skin effect in which an electric current flows through the surface layer can be expected, the surface layer of the wall 1a of the metal member 1 can be efficiently heated.

Also in this embodiment, in the forming quenching strengthening step, as shown in FIG. 7, the sealing member 40 having an inclination corresponding to the inclination of the expansion wall surface 13 of the expansion portion 12 of the metal member 1,
41 is used. Then, the sealing members 40 and 41 are directly attached to the expanded wall surface 13 of the expanded portion 12 of the metal member 1, or
The seal is applied indirectly through the intermediate member. In this way, the seal members 40 and 41 are attached to the expanded wall surface 13 of the metal member 1.
When the on-off valve 51 is opened in the state where the metal member 1 is sealed, the high-pressure gas in the cylinder 50 of the high-pressure gas supply source 5 passes through the supply pipe 54 and the passage 40a of the seal member 40.
To the hollow chamber 10. Thereby, the internal pressure of the gas in the hollow chamber 10 of the metal member 1 is increased, and the wall 1a of the metal member 1 is bulged and deformed (plastically deformed) outward in the radial direction of the wall 1a, and the molding die 3
It is brought into close contact with the molding surface 31 of. Thereby, the wall 1a of the metal member 1 is molded along the molding surface 31.

As described above, according to this embodiment, as in the case of the first and second embodiments, the metal member 1 is heated to the high temperature region during the bulging deformation, so that the metal Even if the member 1 is formed of a high-tensile iron-based metal, the plastic deformability of the metal member 1 can be improved, and the bulging deformability and the formability of the metal member 1 can be improved.

Further, according to the present embodiment, in the forming quenching strengthening step, the wall 1a of the metal member 1 which has been resistance-heated at the quenching temperature or higher is used.
Is bulged and deformed to be brought into close contact with the molding surface 31 of the molding die 3 to quench the wall 1a of the metal member 1 and
The wall 1a can be strengthened. Therefore, according to this embodiment, as in the case of the first embodiment, the wall 1 of the metal member 1 is
It is possible to achieve both moldability and high strength of a.

Furthermore, according to this embodiment, the metal member 1 facing the molding die surface 31 of the molding die 3 is connected to the current-carrying terminal 7 to heat the metal member 1 from the current-carrying terminal 7.
Therefore, immediately after heating the wall 1a of the metal member 1, high-pressure gas can be supplied to the hollow chamber 10 of the metal member 1 to bulge and deform the wall 1a of the metal member 1. Therefore, the step of taking out the metal member 1 heated to the target temperature region from the heating furnace 2 and carrying it to the molding die 3 can be omitted, and the temperature decrease of the metal member 1 can be suppressed. Therefore, the temperature of the metal member 1 can be maintained at a high temperature immediately before forming the metal member 1 and immediately before quenching. Therefore, it is possible to favorably perform both molding and quenching of the metal member 1 while suppressing the temperature drop of the heated metal member 1.

In addition, according to the present embodiment, in order to suppress the temperature rise of the molding die surface 31 of the molding die 3 in the heating step, as necessary, as shown in FIG.
A heat transfer blocking member 9 can be arranged between the metal member 1 and the metal member 1. It is preferable that the heat transfer blocking member 9 has a high heat insulating property and a high magnetic flux blocking property.

(Fourth Embodiment) The fourth embodiment of the present invention will be specifically described below with reference to FIGS. 8 and 9. This embodiment has basically the same configuration as the second embodiment,
Basically, the same effect is obtained. Hereinafter, the description will be focused on the parts that are different from the second embodiment. Also in this embodiment, in the heating step, it is preferable to dispose the metal member 1 so that the strengthening request site of the metal member 1 does not come into close contact with the molding die surface 31 of the molding die 3. In this case, the wall 1 a of the metal member 1 faces the molding die surface 31 of the molding die 3.

Also in this embodiment, the metal member 1 is heated to a temperature range of A1 transformation point or higher or A3 transformation point or higher by resistance heating operation. That is, as shown in FIG.
The energizing terminal 7 is connected to the expanded portion 12 which is the end of the metal member 1 facing the molding die surface 31 of the energizing terminal 7 in that state.
The metal member 1 is energized to heat the wall 1a of the metal member 1 with Joule heat. Further, the conductive member 6 for induction heating is arranged in the hollow chamber 10 of the metal member 1 and a high frequency alternating current is passed through the conductive member 6 to induction heat the wall 1a of the metal member 1.

As described above, according to this embodiment, the metal member 1
In the above heating, since the conductive resistance heating by the current-carrying terminal 7 and the induction heating by the conductive member 6 for induction heating are used in combination, the metal member 1 can be efficiently heated. In particular, in order to bring the conductive member 6 for induction heating close to the portion of the wall 1a of the metal member 1 having the highest degree of plastic workability or the portion at which quenching strengthening is most required, that portion is effective. Further, it can be heated to a high temperature region, and the plastic deformability and hardenability at the site can be enhanced. Note that, also in this embodiment, as can be seen from FIG. 9, the same molding quenching strengthening step as in the second embodiment is performed.

Application Example FIG. 10 shows an application example 1. In Application Example 1, a straight cylindrical metal member 1B as a starting material
Is used to perform the heating step and the forming quenching strengthening step according to each of the above-described examples on the straight cylindrical metal member 1B. FIG. 11 shows an application example 2. In application example 2,
A cylindrical metal member 1C is used as a starting material in which the bent portion 1r is formed in advance by mechanical pressing. Further, the metal member 1C is subjected to groove processing to form the groove 1s. Then, the heating process and the forming quenching strengthening process according to each of the above-described embodiments are performed on the grooved metal member 1C. The metal member 1 according to the present invention can be applied to a beam used for a vehicle suspension mechanism, a suspension member, or a bumper reinforcement attached to a bumper. Further, it can be applied to the center pillar itself arranged between the front seat and the rear seat of the vehicle, or to the center pillar reinforcement for applying the center pillar to reinforce the center pillar.

(Others) According to the first embodiment described above,
Although the widened portions 12 are formed at both ends of the metal member 1, the seal members 40 and 41 can be attached to both ends of the metal member 1 without forming the widened portions 12. The expanded portion 12 of the metal member does not have to be formed before heating, and may be formed at the same time as the sealing after heating. According to the above-described first embodiment, the sealing surfaces 44 of the sealing members 40 and 41 are inclined in the shape of a conical surface, but the shape is not limited to this and may be a straight tube shape.

According to the first embodiment, one sealing member 40
Has a passage 40a connected to the high pressure gas supply source 5, and the other sealing member 41 has a sealing function, but is not connected to the high pressure gas supply source 5. Not limited to this, a passage connected to the high pressure gas supply source 5 may be formed in the other sealing member 40. In this case, high pressure gas is supplied from both ends of the metal member 1.

Further, according to the first embodiment, the high pressure gas supply source 5 includes a cylinder 50 filled with high pressure gas and a cylinder 50.
A valve 52 having an on-off valve 51 for opening and closing the
Pressure gauge 53 for detecting the pressure of the gas sealed in 0
And a flexible supply pipe 54 that functions as a supply passage led out from the valve 52, but the present invention is not limited to this, and the metal member 1 may be bulged and deformed instantaneously by the gas in a high pressure state. In short, the high-pressure gas supply source 5 may be any as long as it can supply gas to the hollow chamber 10 of the metal member 1 to bulge the metal member 1 into a desired shape.

Further, according to the first embodiment, the iron-based metal before quenching which constitutes the metal member 1 is made into high-tensile steel (high-tensile steel) and has a tensile strength of 600 MPa (≈60 kgf / mm.
² ) The above iron-based metals are used, but the material constituting the metal member is not limited to this, and ordinary carbon steel or alloy steel may be used, that is, those that can be quenched and strengthened by the forming die surface 31 of the forming die 3. If it is good.

Further, according to the first embodiment, the heating step for heating the metal member 1 and the forming and quenching strengthening step for bulging and deforming the wall 1a of the metal member 1 are separated, but not limited to this.
Depending on the case, the metal member 1 may be heated in the middle of the forming quenching and strengthening step. For example, the metal member 1 may be heated in the initial stage or the middle stage of the forming and quenching strengthening step of bulging and deforming the wall 1a of the metal member 1.

According to the third embodiment shown in FIG. 6, the current-carrying terminal 7 is connected to the end of the metal member 1, but the structure and material of the current-carrying terminal 7 can be appropriately selected. In short, the energizing terminal 7 may be anything that can energize the metal member 1 and resistance-heat it. According to the third embodiment, the current-carrying terminal 7 is connected to the end portion of the metal member 1, but not limited to this,
It may be connected to an intermediate portion of the metal member 1.

According to the second and third embodiments described above, in the heating step of heating the metal member 1, the molding die 3 is used.
Although the metal member 1 and the metal member 1 are not in contact with each other, the invention is not limited to this.
In order to hold the metal member 1 in the heating step, the mold 3 and the metal member 1 may be partially in contact with each other.
Besides, the present invention is not limited to the above-described embodiments, and can be implemented with appropriate modifications within the scope not departing from the gist.

(Supplementary Note) From the above description, the following technical idea can be understood. (Additional Item 1) A metal member having a hollow chamber formed of a high-tensile iron-based metal and having a tubular shape, and a molding die having a molding die surface, the metal being heated to a temperature range where quenching and strengthening is possible. By increasing the internal pressure of the gas in the hollow chamber of the member, the wall of the metal member is bulged and deformed, and the bulged and deformed wall of the metal member is brought into close contact with the molding die surface of the molding die to perform quenching and strengthening. A method for forming a metal member, which comprises performing a forming quenching and strengthening step. In this case, the metal member formed of the high-tensile iron-based metal can be further strengthened while ensuring moldability. (Additional Item 2) A cylindrical metal member having a hollow chamber,
Using a mold having a mold surface, a heating step of heating the metal member to a temperature region capable of quenching and strengthening, and by increasing the internal pressure of the gas in the hollow chamber of the heated metal member,
A bulging deformation of the wall of the metal member, a bulging deformation of the wall of the metal member in close contact with a molding surface of a molding die, and a molding and quenching strengthening step for quenching and strengthening. A method for forming a metal member. (Additional Item 3) A center pillar reinforcement for reinforcing the center pillar of a vehicle is used, and a cylindrical metal member having a hollow chamber and a forming die having a forming die surface are used to heat to a temperature range where quenching and strengthening can be performed. By increasing the internal pressure of the gas in the hollow chamber of the metal member, the wall of the metal member is bulged and deformed, and the bulged and deformed wall of the metal member is brought into close contact with the molding die surface of the molding die for molding. A method for forming a center pillar reinforcement, which comprises performing a forming and quenching strengthening step for quenching and strengthening. in this case,
While ensuring the formability of the center pillar reinforcement,
The strength can be increased and the side collision resistance of the vehicle can be improved. (Additional Item 4) In each claim or each additional item, the heating of the metal member is performed in a state in which the metal member faces the forming die surface of the forming die.

[0085]

According to the metal member forming method of the present invention, the metal member is heated to a temperature range where quenching and strengthening is possible. Then, in the forming quenching and strengthening step, the wall of the metal member is bulged and deformed by increasing the internal pressure of the gas in the hollow chamber of the metal member, and the bulged and deformed wall of the metal member is brought into close contact with the molding die surface of the molding die. And quenching and strengthening. Since the metal member is heated during the bulging deformation, the plastic deformability of the metal member is improved, and the bulging deformability of the metal member, and thus the formability is improved. Further, in the forming and quenching strengthening step, the wall of the metal member which is bulged and deformed is brought into close contact with the forming die surface of the forming die, whereby the metal member is quenched and strengthened. Therefore, it is possible to achieve both moldability and high strength of the metal member.

According to the metal member forming method of the present invention,
By appropriately adjusting the heating temperature of the metal member in the heating step, the thickness of the metal member, and the cooling ability of the molding surface of the molding die, in the thickness direction of the wall of the metal member, the molding surface of the molding die faces and closely contacts. The cooling rate of one surface layer can be made faster than the cooling rate of the other surface layer facing the molding surface of the molding die.
In other words, in the thickness direction of the wall of the metal member, the cooling rate of the other surface layer facing the forming surface of the forming die is more than the cooling rate of the other surface layer facing the forming surface of the forming die. Can slow down Therefore, in the thickness direction of the wall of the metal member, while improving the hardenability of one surface layer facing and closely contacting the molding surface of the molding die to increase the strength of that portion, It is also possible to suppress the hardenability of the other surface layer facing away from the surface and increase the toughness of that portion.

According to the metal member forming method, the metal member and the metal member forming apparatus of the present invention, the metal member is cooled, or heat treatment such as heating and cooling is performed while the metal member is held in the forming die. As an example, the surface of the metal member can be strengthened by quenching. Therefore, according to the present invention, even for a metal member that is relatively difficult to form, the metal member can be easily formed by the forming means using gas, and the strength of the metal member can be increased efficiently. Well achieved

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing a process of forming expanded portions at both ends of a metal member and arranging the same in a furnace chamber of a heating furnace according to the first embodiment.

FIG. 2 is a cross-sectional view schematically showing a state in which a heated metal member is placed in a molding die according to the first embodiment.

FIG. 3 is a schematic diagram illustrating a state in which a gas is supplied to a hollow chamber of a metal member to bulge a wall of the metal member in a state where a heated metal member is placed in a molding die according to the first embodiment. FIG.

FIG. 4 is a cross-sectional view schematically illustrating a state in which a metal member facing a molding die is heated according to the second embodiment.

FIG. 5 is a cross-sectional view schematically illustrating a state immediately before the gas is supplied to the hollow chamber of the heated metal member that is disposed so as to face the molding die according to the second embodiment.

FIG. 6 is a cross-sectional view schematically showing a state in which a metal member facing a molding die is heated according to the third embodiment.

FIG. 7 is a cross-sectional view schematically showing a state immediately before supplying a gas to a hollow chamber of a heated metal member which is arranged so as to face a molding die according to the third embodiment.

FIG. 8 is a cross-sectional view schematically showing a state in which a metal member facing a molding die is heated according to Example 4.

FIG. 9 is a cross-sectional view schematically illustrating a state immediately before the gas is supplied to the hollow chamber of the heated metal member that is disposed so as to face the molding die according to the fourth embodiment.

FIG. 10 is a perspective view showing an application example 1.

FIG. 11 is a perspective view showing a second application example.

[Explanation of symbols]

In the figure, 1 is a metal member, 10 is a hollow chamber, 1a is a wall, 2 is a heating furnace, 3 is a molding die, 31 is a molding die surface, 33 is a cooling passage (cooling means), 5 is a high pressure gas supply source (gas). Supply means),
Reference numeral 50 is a cylinder, 51 is an opening / closing valve, 6 is a conductive member, and 7 is an energizing terminal.

Claims (17)

[Claims] 1. A cylindrical metal member having a hollow chamber,
Using a mold having a mold surface, the wall of the metal member is swollen and deformed by increasing the internal pressure of the gas in the hollow chamber of the metal member heated to a temperature range where quenching and strengthening is possible. A method for forming a metal member, wherein a wall of the metal member is brought into close contact with a surface of the mold of the mold to perform molding, and a molding and quenching strengthening step of quenching and strengthening is performed. 2. The method for molding a metal member according to claim 1, wherein the operation of increasing the internal pressure of the gas in the hollow chamber of the metal member is performed by supplying the gas to the hollow chamber of the metal member. . 3. The heating of the metal member according to claim 1 or 2, wherein an operation of holding the metal member in a furnace chamber of a heating furnace, an induction heating operation of induction heating the metal member, and a heating of the metal member. A method for forming a metal member, which is carried out by at least one of a resistance heating operation in which electricity is applied. 4. The metal member according to claim 3, wherein the operation of holding the metal member in the furnace chamber of the heating furnace is performed in a state where the furnace chamber of the heating furnace is in a non-oxidizing atmosphere. Molding method. 5. The induction heating operation for induction heating the metal member according to claim 3, wherein a conductive member for induction heating is brought close to the metal member facing the molding die surface of the molding die. The method for forming a metal member, which is performed by applying an alternating current to the conductive member to induction-heat the metal member. 6. The resistance heating operation of energizing the metal member according to claim 3, wherein the energizing terminal is connected to the metal member facing the forming die surface of the forming die, and the metal is removed from the energizing terminal. A method for forming a metal member, which is performed by energizing a member to heat the metal member with Joule heat. 7. The method for molding a metal member according to claim 1, wherein the metal member is iron-based, titanium-based, aluminum-based or copper-based. 8. The metal member according to claim 1, wherein the metal member is iron-based, the metal member is heated to a temperature of A1 transformation point or higher, and in the forming quenching strengthening step, A method for molding a metal member, characterized in that at least a part of the metal member is quenched by bringing the wall of the metal member into close contact with the molding die surface of the molding die. 9. The method for molding a metal member according to claim 1, wherein the mold comprises a cooling means for cooling the mold. 10. The gas supplied to the hollow chamber of the metal member according to claim 1, wherein air, nitrogen gas, nitrogen-enriched gas, argon gas, or argon-enriched gas is used. At least one kind of metal member forming method. 11. The operation of supplying a gas to the hollow chamber of the metal member according to claim 2, wherein an operation of supplying a gas is performed from a high pressure gas supply source capable of supplying a high pressure gas. And a method for forming a metal member. 12. The metal member according to any one of claims 1 to 11, wherein the metal member has an opening that is in communication with the hollow chamber and is formed by an expanded wall surface. A method for molding a metal member, characterized in that a seal having an inclination corresponding to the inclination is applied to the expanded wall surface of the metal member directly or indirectly to seal the opening. 13. A step of loading a tubular metal member having a hollow chamber into a mold, a step of heating the metal member loaded in the mold, and a step of heating in the mold. By supplying gas to the hollow chamber of the metal member, the metal member is plastically deformed, and a predetermined surface of the metal member is brought into close contact with a predetermined surface of the mold, and the metal member is plastically deformed. And then cooling the metal mold by cooling the metal mold while the metal member is inserted in the metal mold, the method for molding a metal member. 14. A step of heating a tubular metal member having a hollow chamber, a step of loading the heated metal member in a molding die, and a step of loading the heating metal member in the molding die after heating. By supplying gas to the hollow chamber of the metal member, the metal member is plastically deformed, and a predetermined surface of the metal member is brought into close contact with a predetermined surface of the molding die, and the metal member is plastically deformed. After that, a step of cooling the metal member by cooling the metal mold while the metal member is inserted in the mold is included. 15. A metal member molded by the method for molding a metal member according to any one of claims 1 to 14. 16. A molding die in which a tubular metal member having a hollow chamber is loaded, gas supply means for supplying gas to the hollow chamber of the metal member heated in the molding die, and the molding. And a cooling unit that cools the metal member loaded in the mold by cooling the mold. 17. The metal member forming apparatus according to claim 16, further comprising means for heating the metal member loaded in the mold.