FORMING SYSTEM

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a bypass continuation of International PCT Application No. PCT/JP2024/022288, filed on June 19, 2024, which claims priority to Japanese Patent Application No. 2023-114492, filed on July 12, 2023, which are incorporated by reference herein in their entirety.

BACKGROUND

Technical Fild

A certain embodiment of the present disclosure relates to a forming system.

Description of Related Art

A forming system described in the related art has been known. In this forming system, a metal pipe material is heated, and the heated metal pipe material is formed by a forming die, so that the shape of the metal pipe material is formed into a shape of a forming surface of the forming die. In addition, the metal pipe material is quenched at the same time as the forming.

SUMMARY

One or more embodiments provide a forming system including: a heater that heats a metal pipe material; and a forming unit that forms, using a forming die, the metal pipe material that is heated, in which the forming unit is provided with a quenching mechanism that performs quenching on a formed product, and the formed product is transported to a cooling mechanism separate from the quenching mechanism during the quenching by the quenching mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram showing a configuration of a forming system, according to an embodiment of the present disclosure.

FIG. 2 illustrates a schematic configuration diagram showing a specific example of the forming system shown in FIG. 1.

FIG. 3 illustrates a schematic configuration diagram showing a specific example of the forming system shown in FIG. 1.

FIG. 4 illustrates a schematic configuration diagram showing a specific example of the forming system shown in FIG. 1.

FIGS. 5A and 5B illustrate diagrams showing a specific example of a jig for cooling.

FIGS. 6A and 6B illustrate diagrams showing a specific example of the jig for cooling.

FIG. 7 illustrates a CCT diagram showing a cooling process of each process.

FIGS. 8A to 8C illustrate diagrams showing a forming die of a forming system, according to a modification example.

FIG. 9 illustrates a diagram showing an example of another formed product.

FIG. 10 illustrates a relationship between a temperature of a planar portion of the formed product after air blowing and a blow-holding time by the forming die, depending on a difference in a blow pressure.

FIG. 11A illustrates a graph showing a relationship between a cooling method and a time of a formed product in a comparative example and an example, and FIG. 11B illustrates a graph showing a ratio of a cooling time by the forming die and a ratio of a cooling time by the cooling mechanism with the entire cooling time as a reference.

DETAILED DESCRIPTION

In the heating, forming, and quenching processes in the related art, the metal pipe material is heated to an austenite region, and the metal pipe material and the die are brought into contact with each other to perform the quenching and the forming at a predetermined cooling rate, so that target mechanical characteristics and dimensional accuracy are achieved. However, in order to obtain the target mechanical characteristics and dimensional accuracy, the formed product is removed from the die after reaching a martensitic transformation finish temperature (Mf point). Therefore, there is a problem that the throughput until the formed product is removed from the die is long, and a time during which one metal pipe material occupies the forming device is long.

On the other hand, in a case where the formed product is removed from the die and air-cooled immediately after the forming in order to improve the throughput, in the shape of the non-uniform cross section, the cooling rate varies depending on the portion, the cooling rate required for the martensitic transformation is not obtained, and the target strength cannot be obtained in the entire formed product. In addition, there is a problem that a cooling start temperature and a cooling rate of each portion of the formed product are non-uniform, warpage occurs due to a difference in thermal contraction amount of each portion, and the target dimensional accuracy cannot be ensured.

According to an embodiment of the present disclosure, it is desirable to provide a forming system that can shorten the throughput of forming while obtaining the desired strength of a formed product.

In the forming system, the forming unit is provided with the quenching mechanism that performs the quenching on the formed product. Therefore, the formed product is rapidly cooled by the quenching mechanism immediately after the forming. Here, the formed product is transported to the cooling mechanism separate from the quenching mechanism during the quenching by the quenching mechanism. As a result, the formed product is rapidly cooled by the cooling mechanism, so that the quenching is completed. Therefore, the desired strength of the formed product can be obtained by the quenching. In addition, the cooling mechanism is a mechanism separate from the quenching mechanism. Therefore, the throughput until the formed product is removed from the forming die is shortened, and the quenching mechanism of the forming die can form the next metal pipe material. As described above, the desired strength of the formed product can be obtained while shortening the throughput of the forming.

The metal pipe material may be cooled from a martensitic transformation start temperature to a martensitic transformation finish temperature after being transported to the cooling mechanism separate from the quenching mechanism. As a result, the quenching of the metal pipe material can be completed by the cooling mechanism separate from the quenching mechanism.

The cooling mechanism may be a jig for cooling that cools the formed product. In this case, the formed product can be cooled by the cooling mechanism at a location different from the forming die. Therefore, the cooling mechanism separate from the quenching mechanism may not be provided in the forming die itself.

The quenching mechanism and the cooling mechanism may be provided at different positions in the same forming die. In this case, a space for providing the cooling mechanism may not be secured at a location other than the forming die.

The forming unit may perform forming by supplying fluid to the metal pipe material to expand the metal pipe material, and a ratio of a cooling time by the cooling mechanism to a cooling time by the forming die may be higher in a case of the metal pipe material having a low blow pressure in the forming unit than in a case of the metal pipe material having a high blow pressure. In this case, even for the metal pipe material having a low blow pressure, the shape can be reliably solidified.

Hereinafter, a preferred embodiment of the present disclosure will be described with reference to the drawings. In the drawings, the same portions or equivalent portions will be denoted by the same reference numerals, and the duplicated description thereof will be omitted.

FIG. 1 is a block diagram showing a configuration of a forming system 100 according to the present embodiment. FIGS. 2 to 4 are schematic configuration diagrams showing specific examples of the forming system 100 shown in FIG. 1.

The forming system 100 is a system that manufactures a formed product 140 (see FIG. 4) by heating a metal material and forming the heated metal material using a forming die. As the metal material, a pipe-shaped metal pipe material 40 shown in FIG. 2 or a plate-shaped metal material 50 shown in FIG. 3 is used. As the metal material, for example, a carbon steel material, an MnB steel material having improved hardenability, or the like is used.

As shown in FIG. 1, the forming system 100 includes a heater 101, a forming device 103 (forming unit) including a forming die 102, and a cooling mechanism 104.

The heater 101 causes a current to flow through the metal material to heat the metal material. The heater 101 includes an electrode for causing the current to flow through the metal material while being in contact with the metal material, and a power supply for causing the current to flow through the electrode. Accordingly, due to an electric resistance of the metal material itself, the metal material itself generates heat by Joule heat (resistive heating). The forming device 103 is a device that forms the metal material heated by the heater 101 using the forming die 102.

For example, as the forming device 103, a configuration shown in FIG. 2 may be used. The forming device 103 shown in FIG. 2 is a device that performs the forming and the quenching by supplying fluid to the heated metal pipe material 40 and bringing the metal pipe material 40 into contact with the forming surface of the forming die. The forming device 103 includes the heater 101.

As shown in FIG. 2, the forming device 103 is a device that forms the metal pipe having a hollow shape by blow forming. Here, the forming device 103 is installed on a horizontal plane. The forming device 103 includes the forming die 102, a drive mechanism 3, a holder 4, the heater 101, a fluid supplier 6, a cooler 7, and a controller 8. In the present specification, a metal pipe material 40 refers to a hollow article before the completion of the forming by the forming device 103. The metal pipe material 40 is a steel-type pipe material that can be quenched. In addition, in a horizontal direction, a direction in which the metal pipe material 40 extends during the forming may be referred to as a "longitudinal direction", and a direction perpendicular to the longitudinal direction may be referred to as a "width direction".

The forming die 102 is a die that forms the metal pipe from the metal pipe material 40, and includes a lower die 11 and an upper die 12 that face each other in an up-down direction. The lower die 11 and the upper die 12 are formed of blocks made of steel. Each of the lower die 11 and the upper die 12 is provided with a recess in which the metal pipe material 40 is accommodated. In a state where the lower die 11 and the upper die 12 are in close contact with each other (die closed state), the respective recesses form a space having a target shape in which the metal pipe material is to be formed. Therefore, the surfaces of the respective recesses are forming surfaces of the forming die 102. The lower die 11 is fixed to a base stage 13 via a die holder or the like. The upper die 12 is fixed to a slide of the drive mechanism 3 via a die holder or the like.

The drive mechanism 3 is a mechanism that moves at least one of the lower die 11 and the upper die 12. In FIG. 2, the drive mechanism 3 has a configuration of moving only the upper die 12. The drive mechanism 3 includes a slide 21 that moves the upper die 12 so that the lower die 11 and the upper die 12 are joined together, a pull-back cylinder 22 as an actuator that generates a force for pulling the slide 21 upward, a main cylinder 23 as a drive source that downward-pressurizes the slide 21, and a drive source 24 that applies a driving force to the main cylinder 23.

The holder 4 is a mechanism that holds the metal pipe material 40 disposed between the lower die 11 and the upper die 12. The holder 4 includes a lower electrode 26 and an upper electrode 27 that hold the metal pipe material 40 on one end side of the forming die 102 in the longitudinal direction, and a lower electrode 26 and an upper electrode 27 that hold the metal pipe material 40 on the other end side of the forming die 102 in the longitudinal direction. The lower electrodes 26 and the upper electrodes 27 on both sides in the longitudinal direction hold the metal pipe material 40 by interposing vicinities of ends of the metal pipe material 40 from the up-down direction. Upper surfaces of the lower electrodes 26 and lower surfaces of the upper electrodes 27 are formed with groove portions having a shape corresponding to an outer peripheral surface of the metal pipe material 40. Drive mechanisms (not shown) are provided in the lower electrodes 26 and the upper electrodes 27 and are movable independently of each other in the up-down direction.

The heater 101 heats the metal pipe material 40. The heater 101 is a mechanism that heats the metal pipe material 40 by energizing the metal pipe material 40. The heater 101 heats the metal pipe material 40 in a state where the metal pipe material 40 is separated from the lower die 11 and the upper die 12, between the lower die 11 and the upper die 12. The heater 101 includes the lower electrodes 26 and the upper electrodes 27 on both sides in the longitudinal direction, and a power supply 28 that causes a current to flow through the metal pipe material 40 via the electrodes 26 and 27.

Here, a state where the metal pipe material 40 is disposed inside the forming die 102 is a state where the metal pipe material 40 is disposed in a space between the upper die 12 and the lower die 11 with respect to the upper die 12 and the lower die 11 facing each other. In such a state, the metal pipe material 40 faces the upper die 12 in a state of being spaced downward with respect to the upper die 12, and faces the lower die 11 in a state of being spaced upward with respect to the lower die 11.

The fluid supplier 6 is a mechanism that supplies a high-pressure fluid into the metal pipe material 40 held between the lower die 11 and the upper die 12. The fluid supplier 6 supplies the high-pressure fluid into the metal pipe material 40 that is brought into a high-temperature state by being heated by the heater 101, to expand the metal pipe material 40. The fluid supplier 6 is provided on both end sides of the forming die 102 in the longitudinal direction. The fluid supplier 6 includes a nozzle 31 that supplies the fluid from an opening of an end of the metal pipe material 40 into the metal pipe material 40, a drive mechanism 32 that moves the nozzle 31 forward and backward with respect to the opening of the metal pipe material 40, and a supply source 33 that supplies the high-pressure fluid into the metal pipe material 40 via the nozzle 31. The drive mechanism 32 brings the nozzle 31 into close contact with the end of the metal pipe material 40 in a state where the sealing performance is ensured during the fluid supply and exhaust, and causes the nozzle 31 to be separated from the end of the metal pipe material 40 in other cases. The fluid supplier 6 may supply a gas such as high-pressure air and an inert gas, as the fluid. Additionally, the fluid supplier 6 may include the heater 101 together with the holder 4 including a mechanism that moves the metal pipe material 40 in the up-down direction as the same device.

The cooler 7 is a mechanism that cools the forming die 102. The cooler 7 can rapidly cool the metal pipe material 40 by cooling the forming die 102 when the expanded metal pipe material 40 comes into contact with the forming surface of the forming die 102. The cooler 7 includes flow paths 36 formed inside the lower die 11 and the upper die 12 and a water circulation mechanism 37 that supplies cooling water and causes the cooling water to circulate through the flow paths 36.

As described above, the quenching mechanism 105 that performs the quenching on the formed product 140 is provided in the forming die 102. The quenching mechanism 105 is formed by the forming surface of the forming die 102 and the cooler 7.

The controller 8 is a device that controls the entire forming device 103. The controller 8 controls the drive mechanism 3, the holder 4, the heater 101, the fluid supplier 6, and the cooler 7. The controller 8 repeatedly performs the operation of forming the metal pipe material 40 using the forming die 102.

The controller 8 closes the forming die 102 by controlling the drive mechanism 3 to lower the upper die 12 and bring the upper die 12 close to the lower die 11. On the other hand, the controller 8 controls the fluid supplier 6 to seal the openings of both ends of the metal pipe material 40 with the nozzle 31 and supply the fluid. As a result, the metal pipe material 40, which is softened by the heating, expands and comes into contact with the forming surface of the forming die 102. Then, the metal pipe material 40 is formed to follow the shape of the forming surface of the forming die 102. In a case where a metal pipe with a flange is formed, a part of the metal pipe material 40 is made to enter a gap between the lower die 11 and the upper die 12, and then die closing is further performed to crush the entering part to form a flange portion. When the metal pipe material 40 comes into contact with the forming surface, the metal pipe material 40 is quenched by being rapidly cooled by the forming die 102 cooled by the cooler 7.

In addition, as the forming device 103, a configuration shown in FIG. 3 may be used. The forming device 103 shown in FIG. 3 is a device that performs the forming and the quenching by bringing the heated flat plate-shaped metal material 50 into contact with the forming surface of the forming die 102. The forming device 103 includes the heater 101.

The forming device 103 includes the forming die 102 that forms the formed product by forming the metal material 50. The forming die 102 includes an upper die 62 that comes into contact with an upper surface of the metal material 50, and a lower die 63 that comes into contact with a lower surface of the metal material 50. The forming surface (lower surface) of the upper die 62 and the forming surface (upper surface) of the lower die 63 may be formed in a shape corresponding to, for example, a hat shape. The forming device 103 includes a driver (not shown) that moves at least one of the upper die 62 and the lower die 63. The forming device 103 forms the metal material 50 into the shape of the formed product by interposing the metal material 50 between the forming surface of the upper die 62 and the forming surface of the lower die 63. In addition, the configuration of the forming die 102 is not limited to the configuration in which the dies, such as the upper die 62 and the lower die 63, are disposed to face each other in the up-down direction, and the dies may be disposed to face each other in a lateral direction. Further, the number of dies constituting the forming die 102 is not limited to two, and the dies may be divided into three or more.

The heater 101 heats the metal material 50 disposed inside the forming die 102. Here, a state where the metal material 50 is disposed inside the forming die 102 has the same meaning as that of FIG. 2, and is a state where the metal material 50 is disposed in a space between the upper die 62 and the lower die 63 with respect to the upper die 62 and the lower die 63 facing each other.

The heater 101 causes the current to flow through the metal material 50 to heat the metal material 50. Specifically, the heater 101 includes a pair of electrodes 70A and 70B, and a power supply 71. The electrodes 70A and 70B are members that come into contact with the metal material 50 and cause the current to flow through the metal material 50. Accordingly, due to the electric resistance of the metal material 50 itself, the metal material 50 itself generates heat by Joule heat (resistive heating). The power supply 71 is connected to the electrodes 70A and 70B and causes the current to flow through the metal material 50 via the electrodes 70A and 70B.

In the example shown in FIG. 3, the electrodes 70A and 70B are in contact with the ends of the metal material 50 in the longitudinal direction. The manner in which the electrodes 70A and 70B are disposed in contact with the metal material 50 is not particularly limited. Although the electrodes 70A and 70B may have a function of holding the metal material 50, a holding mechanism other than the electrodes 70A and 70B may be separately provided. In addition, the configuration in which the electrodes 70A and 70B are provided in the forming device 103 is not particularly limited. For example, the electrodes 70A and 70B may be attached to the forming die 102. In this case, the electrodes 70A and 70B may be removed from the forming die 102 at a timing when the resistive heating is completed and the upper die 62 and the lower die 63 are closed. Alternatively, the electrodes 70A and 70B may be provided at positions separated from the forming die 102 such that the upper die 62 and the lower die 63 do not interfere with the electrodes 70A and 70B even when the upper die 62 and the lower die 63 are closed. Further, the electrodes 70A and 70B may be provided with an actuator (not shown) such that the electrodes 70A and 70B are movable relative to the forming die 102.

As shown in FIG. 3, the forming system 100 includes a controller 80. The controller 80 is a device that controls the entire forming system 100. The controller 80 is electrically connected to the power supply 71 of the heater 101. The controller 80 controls a heating timing by the heater 101 by transmitting a control signal to the power supply 71, and controls a heating temperature by adjusting a magnitude of the current.

In addition, as the forming system 100, a configuration shown in FIG. 4 may be used. In the forming system 100 shown in FIG. 4, the heater 101 and the forming device 103 are provided as separate devices. As a result, the heater 101 can heat the metal pipe material 40 outside the forming die 102. In this case, the heater 101 heats the metal pipe material 40 to an A3 point or higher, that is, 800°C or higher. A state where the heater 101 performs the heating outside the forming die 102 is a state where the heating is performed outside a space facing the dies 12 and 11. In the example shown in FIG. 4, the heater 101 is provided at a different position from the forming device 103. The metal pipe material 40 heated by the heater 101 is set in the forming device 103 by a transport device, such as a robot hand (not shown). Other configurations of the forming device 103 are the same as the configurations of the forming device 103 shown in FIG. 2. The forming system 100 that forms the flat plate-shaped metal material 50 as shown in FIG. 3 may also have a configuration in which the heater 101 performs the heating outside the forming die 102.

Returning to FIG. 1, the cooling mechanism 104 is a mechanism that cools the formed product 140. As shown in FIG. 4, the cooling mechanism 104 is provided at a different position from the quenching mechanism 105. In the present embodiment, the cooling mechanism 104 is provided at a different position from the forming die 102 and outside the forming die 102. The formed product 140 is transported to the cooling mechanism 104 separate from the quenching mechanism 105 during the quenching by the quenching mechanism 105.

The cooling mechanism 104 may be a jig 110 for cooling the formed product 140. The cooling mechanism 104 includes an upper jig 111 that receives the formed product 140 after the forming, and a lower jig 112. The upper jig 111 and the lower jig 112 take heat from the formed product 140 at a contact portion with the formed product 140 by interposing the formed product 140.

A specific example of the jig 110 for cooling will be described with reference to FIGS. 5A through 6B. As shown in FIGS. 5A and 6A, the jig 110 includes die-type members having a contact surface 117 corresponding to an outer peripheral surface of the formed product 140 as the upper jig 111 and the lower jig 112. A cooling circuit 116 through which a refrigerant flows is provided inside the upper jig 111 and the lower jig 112. The cooling circuit 116 is provided to be embedded in the die and provided to extend in the longitudinal direction around the contact surface 117. As a result, the upper jig 111 and the lower jig 112 cool the formed product 140 by bringing the contact surface 117 cooled by the cooling circuit 116 into contact with the formed product 140.

The jig 110 includes, as shown in FIGS. 5B and 6B, a type of member formed by a plurality of ribs 118 as the upper jig 111 and the lower jig 112. As shown in FIG. 6B, in the upper jig 111 and the lower jig 112, the plurality of ribs 118 are disposed in a lattice shape, and an internal space 119 corresponding to the formed product 140 is formed. As a result, the upper jig 111 and the lower jig 112 cool the formed product 140 by bringing each rib 118 into contact with the formed product 140 in the internal space 119 and dissipating heat from each rib 118. A cooling medium (water or the like) may be directly caused to flow between the ribs 118 to promote the cooling of the formed product 140.

FIG. 7 shows cooling processes of each process on a CCT diagram. A graph G1 shows a relationship between a temperature and a time in a case where the formed product 140 is cooled to the Mf point in the forming die 102 after the forming using only the forming device 103. In the process of the graph G1, since the cooling of the formed product 140 is performed in the forming die 102, the time during which one formed product 140 occupies the forming device 103 becomes long. A graph G2 shows a relationship between a temperature and a time in a case where the formed product 140 is removed from the forming die 102 and is naturally air-cooled after the forming is completed. In this case, since the cooling rate of the formed product 140 in the air is low, the martensitic structure is not obtained, and the deformation occurs due to the transformation.

On the other hand, a graph G3 shows a relationship between a temperature and a time in a case where the formed product 140 is transported and cooled by the cooling mechanism 104 after the forming is completed, which is a process according to the present embodiment. In a case where the formed product 140 is cooled by the quenching mechanism 105 of the forming die 102, the graph G3 shows the same plot as the graph G1 (PT1). In a case where the formed product 140 is transported, the graph G3 shows the same plot as the graph G2 (PT2). In a case where the formed product 140 is cooled by the cooling mechanism 104, the graph G3 shows a plot in which the temperature rapidly decreases at the same slope as the graph G1 (PT3). The cooling mechanism 104 rapidly cools the formed product 140 to the Mf point and freezes the formed product 140, so that the martensitic structure is obtained, and the deformation is suppressed. In addition, since the formed product 140 is removed after being formed by the forming die 102, the time during which one formed product 140 occupies the forming device 103 is shortened, and the throughput is improved. In other words, in the present example, the formed product 140 is transported to the cooling mechanism 104 separate from the quenching mechanism 105 during the cooling by the quenching mechanism 105, and is cooled from the martensitic transformation start temperature to the martensitic transformation finish temperature by the cooling mechanism 104. As a result, the throughput is improved while the martensitic structure is obtained even during the quenching.

Next, the operations and effects of the forming system 100 according to the present embodiment will be described.

In the forming system 100, the quenching mechanism 105 that performs the quenching on the formed product 140 is provided in the forming device 103. Therefore, the formed product 140 is rapidly cooled by the quenching mechanism 105 immediately after the forming. Here, the formed product 140 is transported to the cooling mechanism 104 separate from the quenching mechanism 105 during the quenching by the quenching mechanism 105. As a result, the formed product 140 is rapidly cooled by the cooling mechanism 104, so that the quenching is completed. Therefore, the desired strength of the formed product 140 can be obtained by the quenching. In addition, the cooling mechanism 104 is a mechanism separate from the quenching mechanism 105. Therefore, the throughput until the formed product 140 is removed from the forming die 102 is shortened, and the quenching mechanism 105 of the forming die 102 can form the next metal pipe material 40. As described above, the desired strength of the formed product 140 can be obtained while shortening the throughput of the forming.

The metal pipe material 40 may be cooled from the martensitic transformation start temperature to the martensitic transformation finish temperature after being transported to the cooling mechanism 104 separate from the quenching mechanism 105. As a result, the quenching of the metal pipe material 40 can be completed by the cooling mechanism 104 separate from the quenching mechanism 105.

The cooling mechanism 104 may be the jig for cooling that cools the formed product 140. In this case, the formed product 140 can be cooled by the cooling mechanism 104 at a location different from the forming die 102. Therefore, as shown in FIGS. 8A to 8C, the cooling mechanism 104 separate from the quenching mechanism 105 may not be provided in the forming die 102 itself.

Hereinafter, the formed product 140 shown in FIG. 9 will be described. The formed product 140 shown in FIG. 9 includes a pipe main body portion 141, and a pair of flange portions 142. The pipe main body portion 141 includes planar portions 141a and 141b, and side portions 141c and 141d. The flange portions 142 are formed by crushing a part of the metal pipe material 40. In the formed product 140, the cooling rate is lower in the temperatures at measurement points P2 and P4, which are R portions, than in the temperature of measurement points P3 and P5 of the planar portions 141a and 141b, and in order to reach the same temperatures as the measurement points P3 and P5, the temperatures at the measurement points P2 and P4 are cooled about 1.5 seconds later than the temperatures at the measurement points P3 and P5. FIG. 10 shows a relationship between the temperatures of the planar portions 141a and 141b of the formed product 140 after air blowing and a blow-holding time by the forming die, which are different depending on a difference in the blow pressure. It can be seen that, in a case where the blow pressure is high (25 MPa), the temperature is 200°C or lower regardless of the holding time, but in a case where the blow pressure is low, the temperature is not lowered to 200°C or lower when the holding time is short. Therefore, in a case where the cooling ends without sufficient cooling due to the shape of the formed product 140 or the forming conditions, the warpage occurs due to the difference in the thermal contraction amount.

On the other hand, in a case where there is a portion having a low cooling rate as in the formed product 140 of FIG. 9, or in a case where the blow pressure cannot be increased due to manufacturing condition constraints, the cooling mechanism 104 of the forming system 100 according to the present embodiment is used, so that the time during which the forming device 103 is occupied can be shortened, and the warpage due to the difference in thermal contraction can be suppressed by performing sufficient cooling. For example, FIG. 11A is a graph showing a relationship between a cooling method and a time of a formed product for a comparative example in which the cooling is performed using only the forming die 102 and an example in which the cooling by the forming die 102 and the cooling by the cooling mechanism 104 are performed. Here, the time required for the formed product to be cooled to a target temperature (for example, 200°C) after the forming of the formed product is shown. In the comparative example, the entire cooling process is performed by the forming die 102 during a time t1 (for example, 40 seconds). On the other hand, in the example, the cooling by the forming die 102 is performed for a time t2 (for example, 30 seconds) shorter than the time t1, and the formed product is removed from the forming die 102. In this case, the formed product is not cooled to the target temperature. Next, the cooling mechanism 104 cools the formed product until the temperature is lowered to the target temperature over a time t3.

Here, the blow pressure in the forming device 103 may not be increased due to the manufacturing condition constraints depending on the shape or the like of the formed product 140 to be formed. In a case where the blow pressure is low, as shown in FIG. 10, it takes a time to lower the temperature of the formed product to a desired temperature. Therefore, a ratio of the cooling time by the cooling mechanism 104 to the cooling time by the forming die 102 may be higher in a case of the metal pipe material 40 having a low blow pressure in the forming device 103 than in a case of the metal pipe material 40 having a high blow pressure. In this case, even for the metal pipe material 40 having a low blow pressure, the shape can be reliably solidified. Specifically, FIG. 11B is a graph showing a ratio of the cooling time by the forming die 102 and a ratio of the cooling time by the cooling mechanism 104 with the entire cooling time as a reference. As shown in FIG. 11B, a ratio of the cooling time by the cooling mechanism 104 to the cooling time by the forming die 102 in "low blow pressure" is higher than the ratio in "high blow pressure".

The present disclosure is not limited to the above-described embodiment. For example, the forming device of FIGS. 2 to 4 is merely an example, and the forming device may have any configuration without departing from the gist of the present disclosure.

For example, as shown in FIGS. 8A to 8C, the quenching mechanism 105 and the cooling mechanism 104 may be provided at different positions in the same forming die 102. In this case, a space for providing the cooling mechanism 104 may not be secured at a location other than the forming die 102. Specifically, as shown in FIG. 8A, in one forming die 102, a forming surface 55 of the quenching mechanism 105 and the contact surface 117 of the cooling mechanism 104 are formed. After the forming by the quenching mechanism 105 is completed (see FIG. 8A), the formed product 140 is transported to the adjacent cooling mechanism 104 (see FIG. 8B). Then, the die is closed, and the formed product 140 is cooled by the cooling mechanism 104 while being interposed between the die 12 and the die 11 (FIG. 8C).

In the present embodiment, the present disclosure can be applied to a metal material such as a metal plate, in addition to the metal pipe material.

It should be understood that the invention is not limited to the above-described embodiment, but may be modified into various forms on the basis of the spirit of the disclosure. Additionally, the modifications are included in the scope of the disclosure.