FORMING DEVICE

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a bypass continuation of International PCT Application No. PCT/JP2024/022449, filed on June 20, 2024, which claims priority to Japanese Patent Application No. 2023-120971, filed on July 25, 2023, which are incorporated by reference herein in their entirety.

BACKGROUND

Technical Field

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

Description of Related Art

In the related art, a forming device that forms a heated metal material has been known. For example, the related art discloses a forming device including a die including a pair of a lower die and an upper die, a gas supplier that supplies gas into a metal pipe material held between the dies, and a heater that heats the metal pipe material by resistive heating. Such a forming device includes a cooler that causes water to flow through a flow path formed in the die to cool the heated metal pipe during the forming. Therefore, the forming device can perform quenching forming by bringing the cooled die into contact with the metal pipe material.

SUMMARY

One or more embodiments provide a forming device including a heater that heats a metal material; a forming die that forms the metal material that is heated; and a temperature control mechanism that controls a temperature of at least a part of a non-quenching portion of the forming die to form a non-quenching region in a formed product after forming of the metal material, in which the temperature control mechanism includes a heating mechanism that heats the non-quenching portion of the forming die to form the non-quenching region in the formed product during the forming by the forming die, and a cooling mechanism that cools the non-quenching portion of the forming die at a timing after the non-quenching region is formed in the formed product.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 2A illustrates a schematic side view showing a heating and expanding unit. FIG. 2B illustrates a cross-sectional view showing a state where a nozzle seals a metal pipe material.

FIG. 3 illustrates a schematic cross-sectional view showing a temperature controller of a forming die.

FIG. 4 illustrates a schematic diagram showing a metal pipe after forming.

FIG. 5 illustrates a graph showing a forming time and a change in a state of the metal pipe material.

FIG. 6A illustrates a graph showing a timing of temperature control of a temperature control mechanism of the forming device, according to the embodiment, and FIG. 6B illustrates a graph showing a timing of temperature control of a temperature control mechanism of a forming device, according to a comparative example.

DETAILED DESCRIPTION

In the heating, forming, and quenching processes in the related art, the formed product is quenched. Here, a non-quenching portion in which the quenching is not performed may be formed in at least a part of the formed product. In this case, the forming die is heated such that, when the metal material comes into contact with the forming die, the cooling rate becomes low and the temperature remains at a level at which the quenching is not performed. In order to ensure the forming accuracy in the next forming, it is necessary to control the temperature of the forming die by radiating heat to the atmosphere until the next forming is performed in order to suppress the variation in the temperature of the forming die. However, there is a problem that the production efficiency is reduced due to a time loss for such temperature control.

Therefore, it is desirable to provide a forming device that can improve the production efficiency.

The forming device includes the temperature control mechanism that forms the non-quenching region in the formed product after the forming of the metal material by controlling the temperature of the non-quenching portion of at least a part of the forming die. Therefore, the forming device can form the non-quenching portion in which the strength is reduced by not performing the quenching in at least a part of the formed product. The temperature control mechanism includes the heating mechanism that heats the non-quenching portion of the forming die to form the non-quenching region in the formed product during the forming by the forming die. By heating the non-quenching portion by the heating mechanism, the non-quenching region is inhibited from being quenched by reducing the cooling rate when the heated metal material and the non-quenching portion come into contact with each other. Further, the temperature control mechanism includes the cooling mechanism that cools the non-quenching portion of the forming die at the timing after the non-quenching region is formed in the formed product. The cooling mechanism can set a target die temperature for quickly starting the next forming by cooling the non-quenching portion having a high temperature. As a result, it is possible to suppress the time loss for the temperature control for the next forming. As described above, the production efficiency of the forming device can be improved.

The cooling mechanism may cool the non-quenching portion of the forming die at a timing after a bainitic transformation is completed in the formed product. After the bainitic transformation is completed in the non-quenching region of the formed product, the state of the non-quenching region is not affected even when the temperature of the forming die is lowered. Therefore, the timing can be used as an appropriate timing for the cooling mechanism to start the cooling.

The heating mechanism and the cooling mechanism may be provided in the forming die. In this case, the heating mechanism and the cooling mechanism can quickly control the temperature of the forming die.

Hereinafter, a preferred embodiment of a forming device according to 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 schematic configuration diagram showing a forming device 1 according to the present embodiment. As shown in FIG. 1, the forming device 1 is a device that forms a metal pipe having a hollow shape by blow forming. In the present embodiment, the forming device 1 is installed on a horizontal plane. The forming device 1 includes a forming die 2, a drive mechanism 3, a holder 4, a heater 5, a fluid supplier 6, a temperature controller 7, and a controller 8. In addition, in the present specification, a metal pipe material 40 (metal material) refers to a hollow article before the completion of forming via the forming device 1. 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 2 is a die that forms a formed product 140 (see FIG. 4) 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 2. 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 metal pipe material 40 has a quenching region E1 having high strength and a non-quenching region E2 having low strength. Therefore, the forming die 2 performs rapid cooling to increase the cooling rate in the quenching region E1 of the metal pipe material 40, and performs slow cooling to reduce the cooling rate in the non-quenching region E2 of the metal pipe material 40. The upper die 12 and the lower die 11 include quenching portions 12A and 11A that perform quenching on the quenching region E1 and non-quenching portions 12B and 11B that inhibits quenching from being performed on the non-quenching region E2. In the present embodiment, the non-quenching region E2 is provided at a substantially central position of the formed product 140 (metal pipe material 40), and the quenching regions E1 are provided to interpose the non-quenching region E2 in the longitudinal direction. Therefore, the upper die 12 and the lower die 11 include the non-quenching portions 12B and 11B at the central position and the quenching portions 12A and 11A interposing the non-quenching region E2 in the longitudinal direction. As a result, as shown in FIG. 4, the non-quenching region E2 (hatched portion) of the formed product 140 after the forming is a portion having low strength, and the quenching region E1 is a portion having high strength.

The drive mechanism 3 is a mechanism that moves at least one of the lower die 11 and the upper die 12. In FIG. 1, 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 in the longitudinal direction of the forming die 2, and a lower electrode 26 and an upper electrode 27 that hold the metal pipe material 40 on the other end side in the longitudinal direction of the forming die 2. 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 5 heats the metal pipe material 40. The heater 5 is a mechanism that heats the metal pipe material 40 by energizing the metal pipe material 40. The heater 5 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 5 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. The heater may be disposed in a preceding process of the forming device 1 to perform heating externally.

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 5, to expand the metal pipe material 40. The fluid suppliers 6 are provided on both end sides of the forming die 2 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 5 together with the holder 4 including a mechanism that moves the metal pipe material 40 in the up-down direction as the same device.

Components of the holder 4, the heater 5, and the fluid supplier 6 may be configured as a unitized heating and expanding unit 150. FIG. 2A is a schematic side view showing the heating and expanding unit 150. FIG. 2B is a cross-sectional view showing a state where the nozzle 31 seals the metal pipe material 40.

As shown in FIG. 2A, the heating and expanding unit 150 includes the lower electrode 26, the upper electrode 27, an electrode mounting unit 151 in which the electrodes 26 and 27 are mounted, the nozzle 31, the drive mechanism 32, an elevating unit 152, and a unit base 153. The electrode mounting unit 151 includes an elevating frame 154 and electrode frames 156 and 157. The electrode frames 156 and 157 function as a part of a drive mechanism 60 that supports and moves each of the electrodes 26 and 27. The drive mechanism 32 drives the nozzle 31 and moves up and down together with the electrode mounting unit 151. The drive mechanism 32 includes a piston 61 that holds the nozzle 31, and a cylinder 62 that drives the piston. The elevating unit 152 includes an elevating frame base 64 attached to an upper surface of the unit base 153, and an elevating actuator 66 that applies an elevating operation to the elevating frame 154 of the electrode mounting unit 151 by using this elevating frame base 64. The elevating frame base 64 includes guide portions 64a and 64b that guide the elevating operation of the elevating frame 154 with respect to the unit base 153. The elevating unit 152 functions as a part of the drive mechanism 60 of the holder 4. The heating and expanding unit 150 includes a plurality of unit bases 153 of which the upper surfaces have different inclination angles, and allows collectively change and adjustment of inclination angles of the lower electrode 26, the upper electrode 27, the nozzle 31, the electrode mounting unit 151, the drive mechanism 32, and the elevating unit 152 by replacing the unit bases 153.

The nozzle 31 is a cylindrical member into which the end of the metal pipe material 40 can be inserted. The nozzle 31 is supported by the drive mechanism 32 so that a center line of the nozzle 31 coincides with a reference line SL1. An inner diameter of a feed port 31a at an end of the nozzle 31 on the metal pipe material 40 side substantially coincides with an outer diameter of the metal pipe material 40 after expansion forming. In this state, the nozzle 31 supplies the high-pressure fluid from an internal flow path 63 to the metal pipe material 40. Examples of the high-pressure fluid include a gas.

Returning to FIG. 1, the temperature controller 7 is a mechanism that controls a temperature of the forming die 2. The temperature controller 7 can rapidly cool the metal pipe material 40 to perform the quenching when the expanded metal pipe material 40 comes into contact with the forming surface of the forming die 2, by cooling the forming die 2 in the quenching portions 12A and 11A. In addition, the temperature controller 7 can control the temperature of the metal pipe material 40 to a temperature at which the quenching does not occur when the expanded metal pipe material 40 comes into contact with the forming surface of the forming die 2, by performing the temperature control of the forming die 2 in the non-quenching portions 12B and 11B. The temperature controller 7 includes flow paths formed inside the lower die 11 and the upper die 12, a supply mechanism 37 that supplies a temperature control medium and causes the temperature control medium to circulate through the flow paths, and a controller 8 that controls the supply mechanism 37. A more detailed configuration of the temperature controller 7 will be described later.

The controller 8 is a device that controls the entire forming device 1. The controller 8 controls the drive mechanism 3, the holder 4, the heater 5, the fluid supplier 6, and the supply mechanism 37. The controller 8 repeatedly performs the operation of forming the metal pipe material 40 using the forming die 2.

Specifically, the controller 8 controls, for example, a transport timing from a transport device, such as a robot arm, to dispose the metal pipe material 40 between the lower die 11 and the upper die 12 in an open state. Alternatively, a worker may manually dispose the metal pipe material 40 between the lower die 11 and the upper die 12. Additionally, the controller 8 controls an actuator of the holder 4 and the like so that the metal pipe material 40 is supported by the lower electrodes 26 on both sides in the longitudinal direction, and then the upper electrodes 27 are lowered to interpose the metal pipe material 40. In addition, the controller 8 controls the heater 5 to perform resistive heating on the metal pipe material 40. As a result, an axial current flows through the metal pipe material 40, and an electric resistance of the metal pipe material 40 itself causes the metal pipe material 40 itself to generate heat due to Joule heat.

The controller 8 controls the drive mechanism 3 to lower the upper die 12 and bring the upper die 12 close to the lower die 11, thereby closing the forming die 2. 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 2. Then, the metal pipe material 40 is formed to follow a shape of the forming surface of the forming die 2. 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 quenching region E1 of the metal pipe material 40 comes into contact with the forming surface, the metal pipe material 40 is rapidly cooled by being rapidly cooled by using the forming die 2 cooled by the temperature controller 7.

The temperature controller 7 will be described in more detail with reference to FIG. 3. The temperature controller 7 includes cooling mechanisms 70A and 80A and temperature control mechanisms 70B and 80B. The cooling mechanism 70A is provided inside the upper die 12, and cools the forming surface of the upper die 12. The cooling mechanism 80A is provided inside the lower die 11, and cools the forming surface of the lower die 11. The cooling mechanism 70A includes a flow path 71 provided in the quenching portions 12A on both sides of the upper die 12. The flow path 71 cools the forming surface of the quenching portion 12A by causing cooling water from the supply mechanism 37 to flow therethrough. In addition, the cooling mechanism 80A includes a flow path 81 provided in the quenching portions 11A on both sides of the lower die 11. The flow path 81 cools the forming surface of the quenching portion 11A by causing cooling water from the supply mechanism 37 to flow therethrough.

The temperature control mechanism 70B is provided inside the upper die 12, and controls the temperature of the forming surface of the upper die 12. The temperature control mechanism 80B is provided inside the lower die 11, and controls the temperature of the forming surface of the lower die 11. The temperature control mechanisms 70B and 80B form the non-quenching region E2 in the formed product 140 after the forming of the metal pipe material 40, by controlling the temperature of the non-quenching portions 12B and 11B of a part of the forming die 2.

Here, the non-quenching portions 12B and 11B include heating die blocks 12Ba and 11Ba on the forming surface side, and normal die blocks 12Bb and 11Bb on the opposite side. The normal die blocks 12Bb and 11Bb are blocks that connect the quenching portions 12A and 11A on both sides to each other. The temperature control mechanisms 70B and 80B have flow paths 72 and 82 provided in the normal die blocks 12Bb and 11Bb. The same cooling water as that in the flow paths 71 and 81 of the quenching portions 12A and 11A is supplied to the flow paths 72 and 82. The heating die blocks 12Ba and 11Ba are blocks having a higher temperature than the quenching portions 12A and 11A. A heat insulating member 75 (or a void) is provided between the quenching portions 12A and 11A and the heating die blocks 12Ba and 11Ba.

The temperature control mechanisms 70B and 80B include heating mechanisms 79 and 89 and cooling mechanisms 73 and 83. The heating mechanisms 79 and 89 and the cooling mechanisms 73 and 83 are provided in the forming die 2.

The heating mechanisms 79 and 89 are mechanisms that heat the non-quenching portions 12B and 11B of the forming die 2 to form the non-quenching region E2 in the formed product 140 during the forming by the forming die 2. As a result, the temperature control mechanisms 70B and 80B can control the cooling rate of the formed product 140 at the time of coming into contact with the forming surface of the forming die 2 to be low by partially heating the non-quenching portions 12B and 11B. The heating mechanisms 79 and 89 are formed by induction heaters provided inside the heating die blocks 12Ba and 11Ba. The induction heaters heat the heating die blocks 12Ba and 11Ba by heating the surrounding heating die blocks 12Ba and 11Ba by induction heating. However, a heater may be used as the heating mechanisms 79 and 89.

The cooling mechanisms 73 and 83 are mechanisms that cool the non-quenching portions 12B and 11B of the forming die 2 at a timing after the non-quenching region E2 is formed in the formed product 140. The cooling mechanisms 73 and 83 include flow paths provided in the non-quenching portions 12B and 11B on both sides of the heating die blocks 12Ba and 11Ba. The flow paths cool the forming surface of the non-quenching portions 12B and 11B by allowing cooling water from the supply mechanism 37 to flow.

Next, the forming time and the change in the state of the metal pipe material 40 will be described with reference to FIG. 5. A graph G1 shows a state change of the metal pipe material 40 formed by the quenching portions 12A and 11A including the cooling mechanisms 70A and 80A. As shown in the graph G1, the metal of the metal pipe material 40 in contact with the quenching portions 12A and 11A is rapidly cooled, and the temperature is lowered to a martensitic transformation region. As a result, the formed product 140 is quenched, and the quenching region E1 is formed.

A graph G2 shows a state change of the metal pipe material 40 formed by the non-quenching portions 12B and 11B including the temperature control mechanisms 70B and 80B. A graph G2a of a time before a timing P1 in the graph G2 shows a state where the heating mechanisms 79 and 89 heat the non-quenching portions 12B and 11B. A graph G2b of a time after the timing P1 in the graph G2 shows a state where the heating by the heating mechanisms 79 and 89 is stopped, and the cooling mechanisms 73 and 83 cool the non-quenching portions 12B and 11B. As shown in the graph G2a, the metal of the metal pipe material 40 in contact with the non-quenching portions 12B and 11B is cooled at a lower cooling rate than in the graph G1. Therefore, the metal of the metal pipe material 40 transitions to a bainitic transformation region instead of the martensitic transformation region. As a result, the bainitic transformation is completed in the formed product 140, and the non-quenching region E2 is formed. Here, the cooling mechanisms 73 and 83 cool the non-quenching portions 12B and 11B of the forming die 2 at the timing P1 after the bainitic transformation is completed in the formed product 140. As a result, as shown in the graph G2b, the temperature of the formed product 140 is rapidly lowered. The timing P1 may be set in advance to a time at which it is estimated that the bainitic transformation is completed. A state of the temperature in a case where the non-quenching portions 12B and 11B are not cooled by the cooling mechanisms 73 and 83 at the timing P1 is shown in a graph G2c. As shown in the graph G2c, in a case where active cooling is not performed, the cooling rate is low, and it takes time for the temperature to be lowered.

Next, the timing of the temperature control of the temperature control mechanisms 70B and 80B will be described in more detail with reference to FIG. 6A. In FIG. 6A, a graph of “non-quenching portion” shows a temperature control aspect of the non-quenching portions 12B and 11B, “die heating” shows a state where the heating mechanisms 79 and 89 perform heating, “holding” shows a state where neither heating nor cooling is performed, and “die cooling” shows a state where the cooling mechanisms 73 and 83 performs cooling. In FIG. 6A, a graph of “press” shows a pressing aspect of the forming die 2, “pipe clamp” shows a state where the forming by the forming die 2 can be performed, and “press standby” shows a state where the forming die 2 is opened. In FIG. 6A, a graph of “resistive heating current” shows a resistive heating state of the metal pipe material by the heater 5, “resistive heating ON” shows a state where the resistive heating is being performed, and “resistive heating OFF” shows a state where the resistive heating is stopped. A graph of “non-quenching portion temperature” shows the temperature of the non-quenching portions 12B and 11B.

As shown in FIG. 6A, in a state where the forming die 2 is opened, the heating mechanisms 79 and 89 heat the non-quenching portions 12B and 11B (time t1). In a case where the temperature of the non-quenching portions 12B and 11B reaches the target die temperature before the start of the forming, the heating mechanisms 79 and 89 stop the heating (time t2). Next, the heater 5 performs the resistive heating of the metal pipe material 40. In a case where the metal pipe material 40 reaches the target temperature, the resistive heating is stopped, and the forming die 2 moves to the forming position to start the forming (time t3). During the forming, the temperature of the forming die 2 also increases due to the contact between the heated metal pipe material 40 and the forming die 2. In a case where a time at which the bainitic transformation is completed has elapsed, the cooling mechanisms 73 and 83 start the cooling of the non-quenching portions 12B and 11B (time t4). After a predetermined time has elapsed, the forming die 2 is opened to remove the formed product 140 (time t5). In a case where a further time has elapsed, the heating mechanisms 79 and 89 heat the non-quenching portions 12B and 11B (time t6). In this way, one cycle for the forming is completed. A time T1 between the time t3 and the time t5 is the cooling time of the non-quenching portions 12B and 11B by the cooling mechanisms 73 and 83.

Hereinafter, the operations and effects of the forming device 1 according to the present embodiment will be described.

First, a forming device according to a comparative example will be described with reference to FIG. 6B. The forming device according to the comparative example has a structure in which the cooling mechanisms 73 and 83 are removed from the temperature control mechanisms 70B and 80B of the forming device 1 shown in FIG. 3. That is, the non-quenching portions 12B and 11B include only the heating mechanism. FIG. 6B is a graph showing a timing of the temperature control of the temperature control mechanism of the forming device according to the comparative example. As shown in FIG. 6B, in a state where the forming die 2 is opened, the heating mechanisms 79 and 89 heat the non-quenching portions 12B and 11B (time t1). In a case where the temperature of the non-quenching portions 12B and 11B reaches the target die temperature before the start of the forming, the heating mechanisms 79 and 89 stop the heating (time t2). Next, the heater 5 performs the resistive heating of the metal pipe material 40. In a case where the metal pipe material 40 reaches the target temperature, the resistive heating is stopped, and the forming die 2 moves to the forming position to start the forming of the metal pipe material 40 (time t3). Next, the metal pipe material 40 is formed, and the forming die 2 is opened after a predetermined time has elapsed to remove the formed product 140 (time t4). In a case where a further time has elapsed, the heating mechanisms 79 and 89 heat the non-quenching portions 12B and 11B (time t5). In this way, one cycle for the forming is completed. In the forming device according to the comparative example, a standby time T2 for the press is limited by the cooling time of the non-quenching portions 12B and 11B of the forming die 2. Since the non-quenching portions 12B and 11B are cooled by radiation instead of the cooling mechanism, the cooling rate is low (see the graph G2c in FIG. 5). Therefore, the standby time T2 for the press becomes long. As a result, the time per one cycle for the forming becomes long.

On the other hand, the forming device 1 according to the present embodiment includes the temperature control mechanisms 70B and 80B that form the non-quenching region E2 in the formed product 140 after the forming of the metal pipe material 40 by controlling the temperature of at least a part of the non-quenching portions 12B and 11B of the forming die 2. Therefore, the forming device 1 can form the non-quenching portions 12B and 11B in which the strength is reduced by not performing the quenching in at least a part of the formed product 140. The temperature control mechanisms 70B and 80B include the heating mechanisms 79 and 89 that heat the non-quenching portions 12B and 11B of the forming die 2 to form the non-quenching region E2 in the formed product 140 during the forming by the forming die 2. By heating the non-quenching portions 12B and 11B by the heating mechanisms 79 and 89, the non-quenching region E2 can be inhibited from being quenched by reducing the cooling rate when the heated metal pipe material 40 and the non-quenching portions 12B and 11B come into contact with each other. Further, the temperature control mechanisms 70B and 80B include the cooling mechanisms 73 and 83 that cool the non-quenching portions 12B and 11B of the forming die 2 at a timing after the non-quenching region E2 is formed in the formed product 140. The cooling mechanisms 73 and 83 can set the target die temperature for quickly starting the next forming by cooling the non-quenching portions 12B and 11B that are heated to a high temperature (see FIG. 6A). As a result, it is possible to suppress the time loss for the temperature control for the next forming. As described above, the production efficiency of the forming device 1 can be improved.

The cooling mechanisms 73 and 83 may cool the non-quenching portions 12B and 11B of the forming die 2 at a timing after the bainitic transformation is completed in the formed product 140. After the bainitic transformation is completed in the non-quenching region E2 of the formed product 140, the state of the non-quenching region E2 is not affected even when the temperature of the forming die 2 is lowered. Therefore, the timing can be used as an appropriate timing for the cooling mechanisms 73 and 83 to start the cooling.

The heating mechanisms 79 and 89 and the cooling mechanisms 73 and 83 may be provided in the forming die 2. In this case, the heating mechanisms 79 and 89 and the cooling mechanisms 73 and 83 can quickly control the temperature of the forming die 2.

The present disclosure is not limited to the above-described embodiment.

For example, a shape of the metal pipe after the forming is not particularly limited, and a metal pipe with a flange may be used, or a metal pipe without a flange may be used.

The forming device need only be a forming device that heats a metal material to perform the quenching, and a forming device using a hot stamping method may be used. In this case, the metal material is a plate material. Another forming device may be used.

The heating mechanism and the cooling mechanism may be provided outside the die.

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.