Molding device and metal member

Abstract

This molding device for molding an aluminum alloy metal material controls the cooling rate of the aluminum alloy during a solution treatment and imparts a variation in strength of the aluminum alloy after an aging treatment.

Description

Molding device and metal member

[0001] The present disclosure relates to a forming apparatus and a metal member.

[0002] Conventionally, molding devices for molding heated metal materials have been known. For example, Patent Document 1 below discloses a molding device including a mold having a pair of lower and upper molds, a gas supply unit that supplies gas into a metal pipe material held between the molds, and a heating unit that heats the metal pipe material by electrical heating. This molding device also includes a cooling unit that flows water through a flow path formed in the mold to cool the heated metal pipe during molding. This allows the molding device to perform quench molding by bringing the cooled mold into contact with the metal pipe material.

[0003] Japanese Patent Application Laid-Open No. 2009-220141

[0004] In order to reduce weight, aluminum alloys have been used as the metal material. In the forming of aluminum alloys, a thermal aging treatment is carried out after a solution treatment accompanying the forming. While this process produces high-strength aluminum alloy metal parts, it has also been desired to create a strength difference within the metal part.

[0005] Therefore, an object of the present disclosure is to provide a forming device and a metal component that can create a difference in strength within a metal component made of an aluminum alloy after forming.

[0006] A forming apparatus according to one embodiment of the present disclosure is a forming apparatus for forming an aluminum alloy metal material, which controls the cooling rate of the aluminum alloy during solution treatment to create a difference in strength of the aluminum alloy after aging treatment.

[0007] In this forming device, the forming device forms an aluminum alloy metal material. For such aluminum alloys, a thermal aging treatment is performed after solution treatment in the forming device. The forming device controls the cooling rate of the aluminum alloy during the solution treatment. In aluminum alloys, the strength obtained after aging treatment varies depending on the cooling rate of the solution treatment. Therefore, the forming device can provide areas with a fast cooling rate and areas with a slow cooling rate within the aluminum alloy. In this way, by providing areas with different cooling rates within the aluminum alloy, it is possible to obtain areas with different strengths after aging treatment. As described above, a difference in strength can be achieved within the metal component of the aluminum alloy after forming.

[0008] The cooling rate can be controlled by partially heating the mold. In this case, when the heated part of the mold comes into contact with the aluminum alloy, the cooling rate of that part slows down. This makes it easy to control the cooling rate.

[0009] The formed metal component may have a first region having a high number density of precipitates of alloying elements and a second region having a lower number density of precipitates of alloying elements than the first region. The first region has a high number density of precipitates and high strength. The second region has a low number density of precipitates and low strength. In this way, a difference in strength can be created between the first region and the second region.

[0010] A heating and holding time may be set during heating for solution treatment. In this case, time for the aluminum to melt during solution treatment can be secured. This makes it easier to create differences in strength by controlling the cooling rate.

[0011] The metal member has a first region where the number density of precipitates of alloying elements is high, and a second region where the number density of precipitates of alloying elements is lower than that of the first region.

[0012] In this metal component, the first region has a high number density of precipitates and therefore high strength, while the second region has a low number density of precipitates and therefore low strength, thus providing a difference in strength between the first region and the second region.

[0013] According to the present disclosure, it is possible to provide a forming device and a metal component that can create a difference in strength within a formed aluminum alloy metal component.

[0014] 7(a) is a schematic configuration diagram showing a molding device according to an embodiment of the present disclosure; FIG. 2(a) is a schematic side view showing a thermal expansion unit; FIG. 2(b) is a cross-sectional view showing a state when a nozzle seals a metal pipe material; FIG. 2(b) is a schematic cross-sectional view showing a temperature adjustment mechanism of a molding die; FIG. 2(b) is a schematic view showing a metal pipe after molding; FIG. 7(a) is a diagram for explaining the state of aluminum; FIG. 7(b) is an image of the atomic arrangement in a precipitation state; FIG. 7(a) is a graph showing the temperature transition of an aluminum alloy during solution treatment and aging treatment, and FIG. 7(b) is a graph showing various properties of the aluminum alloy; FIG. 7(a) shows the precipitation state at each time shown in FIG. 7(a); FIG. 7(b) is a graph showing the temperature transition of an aluminum alloy during solution treatment and aging treatment; and FIG. 7(b) is a diagram showing the precipitation state at each time in a high-strength region where rapid cooling was performed and a low-strength region where slow cooling was performed.

[0015] Hereinafter, preferred embodiments of a molding apparatus according to the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted.

[0016] FIG. 1 is a schematic diagram of a molding apparatus 1 according to this embodiment. As shown in FIG. 1, the molding apparatus 1 is an apparatus for molding a metal pipe having a hollow shape by blow molding. In this embodiment, the molding apparatus 1 is installed on a horizontal surface. The molding apparatus 1 includes a molding die 2, a drive mechanism 3, a holding unit 4, a heating unit 5, a fluid supply unit 6, a temperature adjustment unit 7, and a control unit 8. In this specification, a metal pipe material 40 (metal material) refers to a hollow article before molding is completed in the molding apparatus 1. The metal pipe material 40 is a pipe material made of a steel type that can be hardened. In addition, among the horizontal directions, the direction in which the metal pipe material 40 extends during molding may be referred to as the "longitudinal direction," and the direction perpendicular to the longitudinal direction may be referred to as the "width direction."

[0017] The forming die 2 is a die for forming a metal pipe 140 (see FIG. 4 ) from a metal pipe material 40, and includes a lower die 11 and an upper die 12 that face each other in the vertical direction. The lower die 11 and the upper die 12 are made of steel blocks. Each of the lower die 11 and the upper die 12 has a recess for accommodating the metal pipe material 40. When the lower die 11 and the upper die 12 are in close contact with each other (closed state), each recess forms a space of the target shape for forming the metal pipe material. Therefore, the surface of each recess becomes the forming surface of the forming die 2. The lower die 11 is fixed to a base 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.

[0018] In this embodiment, the metal pipe material 40 is an aluminum alloy metal material. The metal pipe material 40 has a high-strength region E1 and a low-strength region E2. Therefore, the forming die 2 performs rapid cooling to increase the cooling rate in the high-strength region E1 of the metal pipe material 40, and slow cooling to slow the cooling rate in the low-strength region E2 of the metal pipe material 40. The upper die 12 and the lower die 11 have rapid cooling sections 12A and 11A that quench the high-strength region E1, and slow cooling sections 12B and 11B that prevent quenching in the low-strength region E2. In this embodiment, the low-strength region E2 is provided at approximately the center of the metal pipe 140 (metal pipe material 40), and the high-strength regions E1 are provided to sandwich the low-strength region E2 in the longitudinal direction. Therefore, the upper mold 12 and the lower mold 11 are provided with slow-cooling sections 12B, 11B at their central positions and rapid-cooling sections 12A, 11A that sandwich the low-strength region E2 in the longitudinal direction. As a result, as shown in Figure 4, the low-strength region E2 (hatched portion) of the formed metal pipe 140 becomes a part with low strength, and the high-strength region E1 becomes a part with high strength.

[0019] The drive mechanism 3 is a mechanism that moves at least one of the lower mold 11 and the upper mold 12. In Fig. 1, the drive mechanism 3 is configured to move only the upper mold 12. The drive mechanism 3 includes a slide 21 that moves the upper mold 12 so that the lower mold 11 and the upper mold 12 are aligned with each other, a pull-back cylinder 22 as an actuator that generates a force that pulls the slide 21 upward, a main cylinder 23 as a drive source that pressurizes the slide 21 downward, and a drive source 24 that applies a drive force to the main cylinder 23.

[0020] The holding unit 4 is a mechanism for holding the metal pipe material 40 disposed between the lower mold 11 and the upper mold 12. The holding unit 4 includes a lower electrode 26 and an upper electrode 27 that hold the metal pipe material 40 at one end of the molding die 2 in the longitudinal direction, and a lower electrode 26 and an upper electrode 27 that hold the metal pipe material 40 at the other end of the molding die 2 in the longitudinal direction. The lower electrode 26 and the upper electrode 27 on both sides in the longitudinal direction hold the metal pipe material 40 by sandwiching the vicinity of the end of the metal pipe material 40 from above and below. Grooves having a shape corresponding to the outer peripheral surface of the metal pipe material 40 are formed on the upper surface of the lower electrode 26 and the lower surface of the upper electrode 27. The lower electrode 26 and the upper electrode 27 are provided with drive mechanisms (not shown) that allow them to move independently in the vertical direction.

[0021] The heating unit 5 heats the metal pipe material 40. The heating unit 5 is a mechanism that heats the metal pipe material 40 by passing electricity through the metal pipe material 40. The heating unit 5 heats the metal pipe material 40 between the lower mold 11 and the upper mold 12, while the metal pipe material 40 is spaced apart from the lower mold 11 and the upper mold 12. The heating unit 5 includes the lower electrode 26 and the upper electrode 27 on both sides of the longitudinal direction, and a power source 28 that applies current to the metal pipe material 40 via these electrodes 26, 27. The heating unit may be arranged in a pre-process of the molding device 1 and may be an external heating unit.

[0022] The fluid supply unit 6 is a mechanism for supplying high-pressure fluid into the metal pipe material 40 held between the lower mold 11 and the upper mold 12. The fluid supply unit 6 supplies high-pressure fluid to the metal pipe material 40, which has been heated by the heating unit 5 to a high temperature, thereby expanding the metal pipe material 40. The fluid supply unit 6 is provided on both longitudinal ends of the molding die 2. The fluid supply unit 6 includes a nozzle 31 that supplies fluid into the metal pipe material 40 from an opening at the end of the metal pipe material 40, a drive mechanism 32 that moves the nozzle 31 back and forth relative to the opening of the metal pipe material 40, and a supply source 33 that supplies high-pressure fluid into the metal pipe material 40 through the nozzle 31. The drive mechanism 32 brings the nozzle 31 into close contact with the end of the metal pipe material 40 while ensuring a seal during fluid supply and exhaust, and moves the nozzle 31 away from the end of the metal pipe material 40 at other times. The fluid supply unit 6 may supply a gas such as high-pressure air or an inert gas as the fluid. Furthermore, the fluid supply unit 6 may be integrated into the same device as the holding unit 4 having a mechanism for moving the metal pipe material 40 in the vertical direction, and the heating unit 5 .

[0023] The components of the holding unit 4, the heating unit 5, and the fluid supply unit 6 may be configured as a unitized thermal expansion unit 150. Fig. 2(a) is a schematic side view showing the thermal expansion unit 150. Fig. 2(b) is a cross-sectional view showing the state when the nozzle 31 seals the metal pipe material 40.

[0024] 2( a), the thermal expansion unit 150 includes the above-mentioned lower electrode 26 and upper electrode 27, an electrode mounting unit 151 on which the electrodes 26, 27 are mounted, the above-mentioned nozzle 31 and drive mechanism 32, a lifting unit 152, and a unit base 153. The electrode mounting unit 151 includes a lifting frame 154 and electrode frames 156, 157. The electrode frames 156, 157 function as part of a drive mechanism 60 that supports and moves the electrodes 26, 27. The drive mechanism 32 drives the nozzle 31, and moves it 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 lifting unit 152 includes a lifting frame base 64 attached to the upper surface of the unit base 153, and a lifting actuator 66 that applies lifting and lowering motion to the lifting frame 154 of the electrode mounting unit 151 via the lifting frame base 64. The lifting frame base 64 has guide portions 64a and 64b that guide the lifting and lowering motion of the lifting frame 154 relative to the unit base 153. The lifting unit 152 functions as part of the drive mechanism 60 of the holding part 4. The thermal expansion unit 150 has multiple unit bases 153 with different inclination angles of their upper surfaces, and by replacing these, it is possible to change and adjust the inclination angles of the lower electrode 26, upper electrode 27, nozzle 31, electrode mounting unit 151, drive mechanism 32, and lifting unit 152 all at once.

[0025] 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 a drive mechanism 32 so that the center line of the nozzle 31 coincides with the reference line SL1. The inner diameter of the supply port 31a at the end of the nozzle 31 on the metal pipe material 40 side is approximately equal to the outer diameter of the metal pipe material 40 after expansion molding. In this state, the nozzle 31 supplies high-pressure fluid from an internal flow path 63 to the metal pipe material 40. An example of the high-pressure fluid is gas.

[0026] Returning to FIG. 1 , the temperature adjustment unit 7 is a mechanism for adjusting the temperature of the forming die 2. The temperature adjustment unit 7 adjusts the temperature of the forming die 2 so as to reduce warpage in the low-strength region E2. The temperature adjustment unit 7 cools the forming die 2 in the quenching sections 12A and 11A, thereby enabling the metal pipe material 40 to be rapidly cooled and quenched when it comes into contact with the forming surface of the forming die 2. The temperature adjustment unit 7 also adjusts the temperature of the forming die 2 in the slow-cooling sections 12B and 11B, thereby enabling the metal pipe material 40 to be adjusted to a temperature at which quenching does not occur when it comes into contact with the forming surface of the forming die 2. The temperature adjustment unit 7 includes flow paths formed inside the lower die 11 and the upper die 12, a supply mechanism 37 that supplies and circulates a temperature adjustment medium to the flow paths, and a control unit 8 that controls the supply mechanism 37.

[0027] The control unit 8 is a device that controls the entire molding device 1. The control unit 8 controls the drive mechanism 3, the holding unit 4, the heating unit 5, the fluid supply unit 6, and the supply mechanism 37. The control unit 8 repeatedly performs the operation of molding the metal pipe material 40 in the molding die 2.

[0028] Specifically, the control unit 8 controls the timing of transfer from a transfer device such as a robot arm to place the metal pipe material 40 between the open lower and upper dies 11 and 12. Alternatively, the control unit 8 may have an operator manually place the metal pipe material 40 between the lower and upper dies 11 and 12. The control unit 8 also controls the actuators of the holding unit 4 to support the metal pipe material 40 with the lower electrodes 26 on both longitudinal sides, and then lower the upper electrode 27 to sandwich the metal pipe material 40. The control unit 8 also controls the heating unit 5 to electrically heat the metal pipe material 40. As a result, an axial current flows through the metal pipe material 40, and the metal pipe material 40 itself generates heat through Joule heat due to its own electrical resistance.

[0029] The control unit 8 controls the drive mechanism 3 to lower the upper die 12 and bring it close to the lower die 11, thereby closing the molding die 2. Meanwhile, the control unit 8 controls the fluid supply unit 6 to seal the openings at both ends of the metal pipe material 40 with the nozzle 31 and supply fluid. As a result, the metal pipe material 40, softened by heating, expands and comes into contact with the molding surface of the molding die 2. The metal pipe material 40 is then molded to conform to the shape of the molding surface of the molding die 2. When a metal pipe with a flange is formed, a portion of the metal pipe material 40 is inserted into the gap between the lower die 11 and the upper die 12, and then the mold is closed to crush the inserted portion and form a flange portion. When the high-strength region E1 of the metal pipe material 40 comes into contact with the molding surface, the metal pipe material 40 is rapidly cooled by the molding die 2, which is cooled by the temperature adjustment unit 7.

[0030] The forming apparatus 1 controls the cooling rate of the aluminum alloy during solution treatment to provide a difference in strength of the aluminum alloy after aging treatment. Solution treatment is a process in which a heated metal pipe material 40 is formed using dies 11, 12. Aging treatment is a process in which artificial aging (paint baking) is performed after forming the metal pipe 140 using the forming apparatus 1. The forming apparatus 1 brings the quenching sections 11A, 12A into contact with each other to increase the cooling rate of the high-strength region E1 of the aluminum alloy metal pipe material 40, thereby quenching it. The forming apparatus 1 brings the slow-cooling sections 11B, 12B into contact with each other to decrease the cooling rate of the low-strength region E2 of the aluminum alloy metal pipe material 40, thereby gradual cooling it. In this way, the forming apparatus 1 provides a difference in strength of the aluminum alloy metal pipe 140 after aging treatment. The high-strength region E1 after aging treatment has lower strength than the low-strength region E2. The cooling rate is controlled by partially heating the dies 11, 12. Specifically, the cooling-resistant portions 11B and 12B of the molds 11 and 12 are partially heated.

[0031] The temperature adjustment unit 7 will be described in more detail with reference to FIG. 3 . The temperature adjustment unit 7 includes temperature adjustment mechanisms 70 and 80 that adjust the temperature of the molding die 2. The temperature adjustment mechanism 70 is provided inside the upper die 12 and adjusts the temperature of the molding surface of the die 12. The temperature adjustment mechanism 80 is provided inside the lower die 11 and adjusts the temperature of the molding surface of the die 11. The temperature adjustment mechanism 70 has flow paths 71 provided in the quenching sections 12A on both sides of the die 12. The flow paths 71 cool the molding surfaces of the quenching sections 12A by flowing cooling water from the supply mechanism 37. The temperature adjustment mechanism 80 also has flow paths 81 provided in the quenching sections 11A on both sides of the die 11. The flow paths 81 cool the molding surfaces of the quenching sections 11A by flowing cooling water from the supply mechanism 37.

[0032] Here, the cooling section 12B, 11B includes a heated mold block 12Ba, 11Ba on the molding surface side and a normal mold block 12Bb, 11Bb on the opposite side. The normal mold block 12Bb, 11Bb is a block that connects the quenching sections 12A, 11A on both sides. The temperature adjustment mechanism 70, 80 has flow paths 72, 82 provided in the normal mold block 12Bb, 11Bb. The flow paths 72, 82 are supplied with cooling water similar to the flow paths 71, 81 of the quenching section 12A, 11A. The heated mold block 12Ba, 11Ba is a block that has a higher temperature than the quenching section 12A, 11A. A heat insulating member 75 (or an air gap) is provided between the quenching section 12A, 11A and the heated mold block 12Ba, 11Ba. The temperature adjustment mechanisms 70, 80 have flow paths 73, 83 provided in the heated mold blocks 12Ba, 11Ba. The flow paths 73, 83 pass a fluid having a higher temperature than the flow paths 71, 81, thereby making the molding surfaces of the slow-cooling sections 12B, 11B at a higher temperature than the molding surfaces of the quenching sections 12A, 11A. Note that the temperature adjustment mechanisms 70, 80 may include a heater or the like instead of the flow paths 73, 83. In this way, the temperature adjustment mechanisms 70, 80 can control the cooling rate of the aluminum alloy during the solution treatment (forming) to be slower by partially heating the slow-cooling sections 11B, 12B.

[0033] Next, with reference to Figures 5 to 10, we will explain the reasons for creating differences in strength among aluminum alloys and the control of the cooling rate of the aluminum alloy for this purpose. First, with reference to Figures 5 and 6, we will explain the precipitation of alloying elements in aluminum. Figure 5 is a diagram illustrating the state of alloying elements in aluminum. The graph in Figure 5 shows the relationship between the concentration ratio of aluminum and alloying elements in the aluminum alloy and temperature. The conceptual diagram on the right side of the graph shows the metal structure of the aluminum alloy in each state. "1" in the graph indicates the state after solution treatment of the aluminum alloy (metal pipe 140). At "1," the aluminum alloy is in a "solid solution state," in which the alloying elements are completely dissolved. "2" indicates the state after quenching the aluminum alloy. At "2," the aluminum alloy is in a "supersaturated solid solution state," in which the precipitated phase is normally more stable, but by rapidly cooling in the solid solution state, the alloying elements are dissolved. "3" indicates the state after aging treatment of the aluminum alloy at a relatively low temperature after quenching. In "3", the aluminum alloy is in a state where a "metastable precipitate phase" has precipitated. "4" indicates the state when the aluminum alloy is aged at a relatively high temperature after quenching. In "4", the aluminum alloy is in a state where a "stable precipitate phase" has precipitated. "5" indicates the state when the aluminum alloy is slowly cooled. In "5", the "stable precipitate phase" precipitates during cooling by slow cooling. In this case, precipitation occurs not only within the crystal grains but also at the crystal grain boundaries. For strengthening aluminum alloys, it is effective for precipitates to precipitate densely within the crystal grains. In "4", precipitates precipitate more densely within the crystal grains than in "5".

[0034] 6 shows an image of the atomic arrangement in a precipitated state. Fig. 6(a) shows an image of the atomic arrangement in a solid solution. Fig. 6(b) shows an image of the atomic arrangement in an intermediate phase. Fig. 6(c) shows an image of the atomic arrangement in a stable precipitate phase (parallel phase).

[0035] Next, the treatment time of the aging treatment will be described with reference to Figures 7 and 8. Figure 7(a) is a graph showing the transition of the temperature of an aluminum alloy during solution treatment and aging treatment. As shown in Figure 7(a), time t1 is the time immediately before the start of the aging treatment. Time t2 is a time during the aging treatment. Time t3 is the heating end time of the aging treatment when the aging treatment time is set appropriately. Time t4 is the heating end time of the aging treatment when the aging treatment time is set improperly.

[0036] Graph G1 in FIG. 7(b) is a graph showing the precipitate size of alloying elements in an aluminum alloy. Graph G2 is a graph showing the strength of the aluminum alloy. Graph G3 is a graph showing the number density of precipitates of alloying elements in an aluminum alloy. As shown in graph G1, the size of the precipitates increases with time. On the other hand, as shown in graph G2, the strength of the aluminum alloy peaks at time t3 and then decreases. As shown in graph G3, the number density of precipitates peaks earlier than time t3 and then decreases. FIG. 8 shows the precipitation state at times t1, t2, t3, and t4. At time t1, a supersaturated solid solution state is reached. At time t2, a metastable precipitate phase precipitates. At time t3, a high-density stable precipitate phase precipitates. At time t4, a low-density stable precipitate phase precipitates. As described above, it can be seen that if the aging treatment is performed until time t4, overaging occurs, the density of the stable precipitate phase decreases, and the strength of the aluminum alloy also decreases. Therefore, if the heating for the aging treatment is completed at time t3, which is the appropriate aging treatment time, the density of the stable precipitate phase increases, and the strength of the aluminum alloy increases.

[0037] Next, with reference to Figures 9 and 10, the precipitation state in the high-strength region E1, where rapid cooling is performed in the quenching portions 11A and 12A, and the low-strength region E2 (see Figure 3), where slow cooling is performed in the slow-cooling portions 11B and 12B, will be described. Figure 9 is a graph showing the temperature transition of the aluminum alloy during solution treatment and aging treatment. The solid line graph A of the solution treatment shows the temperature of the high-strength region E1, where rapid cooling is performed, and the dashed line graph B shows the temperature of the low-strength region E2, where slow cooling is performed. During heating for solution treatment, a heating holding time T is set. Once heating for solution treatment begins and the temperature rises to a predetermined temperature, the temperature is maintained for the heating holding time T. The heating temperature of the aluminum alloy is preferably below the melting point of aluminum and above the solution temperature (around 500°C). Time t5 is the time when cooling begins when the aluminum alloy comes into contact with the molds 11 and 12. The temperature transition up to time t5 is the same in both regions E1 and E2. The temperature transition during the aging treatment is the same for both regions E1 and E2. Time t6 is the time when cooling in the low strength region E2 is completed. Time t7 is the time when the heating temperature during the aging treatment is reached. Time t8 is the time after the aging treatment is completed.

[0038] FIG. 10 shows the precipitation states at times t5, t6, t7, and t8 in the high-strength region E1, which was rapidly cooled, and the low-strength region E2, which was slowly cooled. In the high-strength region E1, which was rapidly cooled, a supersaturated solid solution state is maintained until time t6. A metastable precipitate phase precipitates at time t7, during aging treatment. A high-density stable precipitate phase precipitates at time t8, after aging treatment is completed. On the other hand, in the low-strength region E2, which was slowly cooled, precipitates have already precipitated at time t6, after solution treatment but before aging treatment. Furthermore, precipitates precipitate not only within the crystal grains but also at the crystal grain boundaries. Therefore, in the low-strength region E2, the number density of precipitates within the crystal grains at time t8, after the final aging treatment, is low, resulting in a decrease in strength. As a result, the formed metal pipe 140 has a high-strength region E1 (first portion) in which the number density of alloy element precipitates is high, and a low-strength region E2 (second portion) in which the number density of alloy element precipitates is lower than that of the high-strength region E1.

[0039] Next, the operation and effects of the molding device 1 according to this embodiment will be described.

[0040] This forming apparatus 1 forms an aluminum alloy metal pipe material 40. For such aluminum alloys, thermal aging treatment is performed after solution treatment by the forming apparatus 1. The forming apparatus 1 controls the cooling rate of the aluminum alloy during the solution treatment. In aluminum alloys, the strength obtained after aging treatment varies depending on the cooling rate of the solution treatment. Therefore, the forming apparatus 1 can create areas within the aluminum alloy with a fast cooling rate and areas with a slow cooling rate. In this way, by creating areas within the aluminum alloy with different cooling rates, it is possible to obtain areas with different strengths after aging treatment. As described above, it is possible to create differences in strength within the formed aluminum alloy metal pipe 140.

[0041] The cooling rate may be controlled by partially heating the molds 11 and 12. In this case, when the heated portions (slow-cooling portions 11B and 12B) of the molds 11 and 12 come into contact with the aluminum alloy, the cooling rate of those portions slows down. This makes it easy to control the cooling rate.

[0042] The formed metal pipe 140 may have a high-strength region E1 (first portion) where the number density of alloy element precipitates is high, and a low-strength region E2 (second portion) where the number density of alloy element precipitates is lower than that of the high-strength region E1. The high-strength region E1 has a high number density of precipitates and is therefore strong. The low-strength region E2 has a low number density of precipitates and is therefore weak. In this way, a difference in strength can be achieved between the high-strength region E1 and the low-strength region E2.

[0043] A heating and holding time may be provided during heating for solution treatment. In this case, time for the alloying elements to form a solid solution can be secured during solution treatment. This makes it easier to achieve differences in strength by controlling the cooling rate.

[0044] The present disclosure is not limited to the above-described embodiments.

[0045] For example, the shape of the metal pipe after molding is not particularly limited, and it may be a metal pipe with a flange or a metal pipe without a flange.

[0046] The forming device may be a forming device that heats and quenches a metal material, and may be a forming device for a hot stamping method. In this case, the metal material is a plate material. However, other forming devices may also be used.

[0047] [Mode 1] A molding apparatus for molding an aluminum alloy metal material, which controls the cooling rate of the aluminum alloy during solution treatment, and provides a difference in strength of the aluminum alloy after aging treatment. [Mode 2] The molding apparatus according to Mode 1, wherein the cooling rate is controlled by partially heating the mold. [Mode 3] The molding apparatus according to Mode 1 or 2, wherein the metal member after molding has a first region having a high number density of precipitates of alloying elements and a second region having a lower number density of precipitates of alloying elements than the first region. [Mode 4] The molding apparatus according to any one of Modes 1 to 3, wherein a heating holding time is provided during heating for the solution treatment. [Mode 5] A metal member having a first region having a high number density of precipitates of alloying elements and a second region having a lower number density of precipitates of alloying elements than the first region.

[0048] 1...molding device, 2...molding die, 11, 12...die, 40...metal pipe material (metal material), 140...metal pipe (metal member), E1...high strength region (first portion), E2...low strength region (second portion).

Claims

1. A molding apparatus for molding a metallic material of an aluminum alloy, which is provided in a mold of the molding apparatus and controls the cooling rate of the aluminum alloy during solution treatment by a temperature adjustment unit that adjusts the temperature of the mold, and provides a difference in the strength of the aluminum alloy after aging treatment.

2. The molding apparatus according to claim 1, wherein the control of the cooling rate is achieved by partially heating the mold.

3. The molded metal member has a first part with a high number density of alloy element precipitates and a second part with a lower number density of alloy element precipitates compared to the first part.

4. The molding apparatus according to claim 1, wherein a heating and holding time is provided during the heating of the solution treatment.

5. A metal member having a first part with a high number density of alloy element precipitates and a second part with a lower number density of alloy element precipitates compared to the first part.