Molding device and metal component

Abstract

The forming device is used for forming the aluminum alloy metal material, and the cooling speed of the aluminum alloy is controlled during solution treatment, so that the strength of the aluminum alloy is different after aging treatment.

Description

Technical Field

[0001] The invention relates to a forming device and a metal component. Background Art

[0002] In the past, there are known molding devices for molding heated metal materials. For example, in the following patent document 1, a molding device is disclosed, which includes: a mold having a lower mold and an upper mold that form a pair with each other; a gas supply unit that supplies gas into a metal tube material held between the molds; and a heating unit that heats the metal tube material by energizing it. This molding device includes a cooling unit that allows water to flow through a flow path formed in the mold to cool the heated metal tube during molding. Thus, the molding device can perform quench molding by bringing the cooled mold into contact with the metal tube material.

[0003] Previous technical literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-220141 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] Here, aluminum alloy is sometimes used as a metal material from the viewpoint of light weight. In the forming of aluminum alloy, after the solution treatment accompanying the forming, thermal aging treatment is performed. Through this step, a high-strength aluminum alloy metal part can be obtained, but it is also required to form a strength difference in the metal part.

[0008] Therefore, an object of the present invention is to provide a forming device and a metal part that can form a strength difference in an aluminum alloy metal part after forming.

[0009] Means for solving technical problems

[0010] In a forming device according to one aspect of the present invention, an aluminum alloy metal material is formed, wherein the cooling rate of the aluminum alloy is controlled during solution treatment so that a difference is generated in the strength of the aluminum alloy after aging treatment.

[0011] In the forming device, the forming device forms an aluminum alloy metal material. For this aluminum alloy, after the solution treatment is carried out by the forming device, a thermal aging treatment is carried out. The forming device controls the cooling rate of the aluminum alloy during the solution treatment. In the aluminum alloy, the strength obtained after the aging treatment changes according to the cooling rate of the solution treatment. Therefore, the forming device can form a portion with a fast cooling rate and a portion with a slow cooling rate in the aluminum alloy. In this way, if portions with different cooling rates are formed in the aluminum alloy, portions with different strengths can be obtained after the aging treatment. As a result, a strength difference can be formed in the metal parts of the aluminum alloy after forming.

[0012] The cooling rate can be controlled by locally heating the mold. At this time, if the heated part of the mold contacts the aluminum alloy, the cooling rate of this part will be slowed down. Thus, the cooling rate can be easily controlled.

[0013] The formed metal part may have a first portion having a high number density of alloy element precipitates and a second portion having a lower number density of alloy element precipitates than the first portion. The first portion has a high number density of precipitates and high strength. The second portion has a low number density of precipitates and low strength. In this way, a strength difference can be formed between the first portion and the second portion.

[0014] The heating holding time can be set during the heating process of the solution treatment. In this case, the time for dissolving aluminum can be ensured during the solution treatment. Thus, it is easy to set the strength difference by controlling the cooling rate.

[0015] The metal component includes a first portion having a high number density of alloy element precipitates and a second portion having a lower number density of alloy element precipitates than the first portion.

[0016] In this metal component, the first portion has a high number density of precipitates and a high strength, while the second portion has a low number density of precipitates and a low strength. Thus, a strength difference can be formed between the first portion and the second portion.

[0017] Effects of the Invention

[0018] According to the present invention, it is possible to provide a forming device and a metal component that can form a strength difference in an aluminum alloy metal component after forming. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram showing a molding device according to an embodiment of the present invention.

[0020] Figure 2 (a) is a schematic side view showing the heating expansion unit. Figure 2 (b) is a cross-sectional view showing a state where the nozzle seals the metal tube material.

[0021] Figure 3 It is a schematic cross-sectional view showing a temperature adjustment mechanism of a molding die.

[0022] Figure 4 It is a schematic diagram showing a metal pipe after forming.

[0023] Figure 5 It is a diagram for explaining the state of aluminum.

[0024] Figure 6 An image showing the atomic arrangement in the precipitated state.

[0025] Figure 7 (a) is a graph showing the temperature change of the aluminum alloy during solution treatment and aging treatment. Figure 7 (b) is a graph showing various properties of aluminum alloy.

[0026] Figure 8 Shows Figure 7 The precipitation state at each time is shown in (a).

[0027] Fig. 9 It is a graph showing the temperature change of the aluminum alloy during solution treatment and aging treatment.

[0028] Fig.10 It is a diagram showing the precipitation state at each time point in the high-strength region subjected to rapid cooling and the low-strength region subjected to slow cooling.

[0029] Explanation of symbols:

[0030] 1-forming device, 2-forming mold, 11, 12-molds, 40-metal tube material (metal material), 140-metal tube (metal part), E1-high strength area (first part), E2-low strength area (second part). DETAILED DESCRIPTION

[0031] Hereinafter, preferred embodiments of the molding device of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, the same or equivalent parts are marked with the same reference numerals, and repeated description is omitted.

[0032] Figure 1 FIG. 1 is a schematic structural diagram of the molding device 1 according to the present embodiment. Figure 1As shown, the molding device 1 is a device for molding a metal tube having a hollow shape by blow molding. In the present embodiment, the molding device 1 is arranged on a horizontal plane. The molding device 1 comprises a molding die 2, a drive mechanism 3, a holding portion 4, a heating portion 5, a fluid supply portion 6, a temperature regulating portion 7 and a control portion 8. In addition, in the present specification, the metal tube material 40 (metal material) refers to a hollow object before the molding in the molding device 1 is completed. The metal tube material 40 is a tube material of a steel type that can be quenched. In addition, the direction in which the metal tube material 40 extends in the horizontal direction during molding is sometimes referred to as the "length direction", and the direction orthogonal to the length direction is referred to as the "width direction".

[0033] The forming die 2 is used to form a metal tube 140 (see Figure 4 ) and has a lower mold 11 and an upper mold 12 that are opposite to each other in the up and down direction. The lower mold 11 and the upper mold 12 are composed of steel blocks. The lower mold 11 and the upper mold 12 are respectively provided with recesses for accommodating the metal tube material 40. When the lower mold 11 and the upper mold 12 are in close contact with each other (closed mold state), a space of a target shape to be formed of the metal tube material is formed by each recess. Therefore, the surface of each recess becomes the molding surface of the molding mold 2. The lower mold 11 is fixed to the base 13 via a mold base, etc. The upper mold 12 is fixed to the sliding part of the driving mechanism 3 via a mold base, etc.

[0034] Here, in the present embodiment, the metal tube material 40 is an aluminum alloy metal material. The metal tube material 40 has a high-strength region E1 with high strength and a low-strength region E2 with low strength. Therefore, the forming die 2 performs rapid cooling to accelerate the cooling rate of the metal tube material 40 in the high-strength region E1, and performs slow cooling to slow the cooling rate of the metal tube material 40 in the low-strength region E2. The upper die 12 and the lower die 11 have: a rapid cooling portion 12A, 11A, which quenches the high-strength region E1; and a slow cooling portion 12B, 11B, which prevents the low-strength region E2 from being quenched. In the present embodiment, the low-strength region E2 is provided at a substantially central position of the metal tube 140 (metal tube material 40), and the high-strength region E1 is provided in a manner that the low-strength region E2 is separated in the length direction. Therefore, the upper die 12 and the lower die 11 have slow cooling portions 12B, 11B at the central position and rapid cooling portions 12A, 11A that separate the low-strength region E2 in the length direction. Therefore, if Figure 4 As shown, the low-strength region E2 (hatched portion) of the formed metal pipe 140 becomes a portion with locally low strength, and the high-strength region E1 becomes a portion with high strength.

[0035] The driving mechanism 3 is a mechanism for moving at least one of the lower mold 11 and the upper mold 12. Figure 1 In the embodiment, the driving mechanism 3 has a structure that moves only the upper mold 12. The driving mechanism 3 includes: a slide 21 that moves the upper mold 12 so that the lower mold 11 and the upper mold 12 are closed together; a pull-back cylinder 22 as an actuator that generates a force to pull the slide 21 upward; a main cylinder 23 as a driving source that lowers and pressurizes the slide 21; and a driving source 24 that applies driving force to the main cylinder 23.

[0036] The holding part 4 is a mechanism for holding the metal tube material 40 disposed between the lower die 11 and the upper die 12. The holding part 4 includes a lower electrode 26 and an upper electrode 27 for holding the metal tube material 40 at one end side of the molding die 2 in the longitudinal direction, and a lower electrode 26 and an upper electrode 27 for holding the metal tube material 40 at the other end side 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 tube material 40 by clamping the vicinity of the end of the metal tube material 40 from the upper and lower directions. In addition, grooves having a shape corresponding to the outer peripheral surface of the metal tube 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 a driving mechanism (not shown) so that the lower electrode 26 and the upper electrode 27 can be independently moved in the upper and lower directions.

[0037] The heating unit 5 heats the metal tube material 40. The heating unit 5 is a mechanism that heats the metal tube material 40 by passing electricity through the metal tube material 40. The heating unit 5 heats the metal tube material 40 when the metal tube material 40 is between the lower mold 11 and the upper mold 12 and the metal tube material 40 is separated from the lower mold 11 and the upper mold 12. The heating unit 5 includes a lower electrode 26 and an upper electrode 27 on both sides in the longitudinal direction, and a power source 28 that allows current to flow to the metal tube material 40 via these electrodes 26 and 27. In addition, the heating unit can be arranged in the previous process of the molding device 1 and perform heating externally.

[0038] The fluid supply unit 6 is a mechanism for supplying high-pressure fluid into the metal tube 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 tube material 40 heated by the heating unit 5 to a high-temperature state, so as to expand the metal tube material 40. The fluid supply unit 6 is provided at both ends of the molding die 2 in the longitudinal direction. The fluid supply unit 6 includes: a nozzle 31 for supplying fluid into the metal tube material 40 from the opening at the end of the metal tube material 40; a driving mechanism 32 for moving the nozzle 31 forward and backward relative to the opening of the metal tube material 40; and a supply source 33 for supplying high-pressure fluid into the metal tube material 40 via the nozzle 31. The driving mechanism 32 makes the nozzle 31 close to the end of the metal tube material 40 in a state of ensuring sealing when supplying the fluid and when exhausting the fluid, and separates the nozzle 31 from the end of the metal tube material 40 at other times. In addition, the fluid supply unit 6 may also supply a gas such as high-pressure air or an inert gas as the fluid. Furthermore, the fluid supply unit 6, the holding unit 4 having a mechanism for moving the metal tube material 40 in the vertical direction, and the heating unit 5 may be provided as the same device.

[0039] The components of the holding unit 4 , the heating unit 5 , and the fluid supply unit 6 may be configured as a unitized heating expansion unit 150 . Figure 2 (a) is a schematic side view showing the heating expansion unit 150. Figure 2 (b) is a cross-sectional view showing a state where the nozzle 31 seals the metal tube material 40 .

[0040] like Figure 2As shown in (a), the heating expansion unit 150 includes the lower electrode 26 and the upper electrode 27, the electrode mounting unit 151 on which the electrodes 26 and 27 are mounted, the nozzle 31 and the driving mechanism 32, the lifting unit 152, and the unit base 153. The electrode mounting unit 151 includes a lifting frame 154 and electrode frames 156 and 157. The electrode frames 156 and 157 function as a part of the driving mechanism 60 that supports and moves the electrodes 26 and 27. The driving mechanism 32 drives the nozzle 31 and is lifted and lowered together with the electrode mounting unit 151. The driving 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 mounted on the upper surface of the unit base 153; and a lifting actuator 66, which imparts a lifting action to the lifting frame 154 of the electrode mounting unit 151 through these lifting frame bases 64. The lifting frame base 64 has guide parts 64a and 64b for guiding the lifting frame 154 to perform lifting and lowering actions relative to the unit base 153. The lifting unit 152 functions as a part of the driving mechanism 60 of the holding part 4. The heating expansion unit 150 has a plurality of unit bases 153 with different inclination angles of the upper surface, and by replacing these unit bases, the inclination angles of the lower electrode 26 and the upper electrode 27, the nozzle 31, the electrode mounting unit 151, the driving mechanism 32, and the lifting unit 152 can be changed and adjusted at the same time.

[0041] The nozzle 31 is a cylindrical member that can be inserted into the end of the metal tube material 40. The nozzle 31 is supported by the drive mechanism 32 in such a manner 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 tube material 40 side is substantially consistent with the outer diameter of the metal tube material 40 after expansion molding. In this state, the nozzle 31 supplies a high-pressure fluid to the metal tube material 40 through the internal flow path 63. In addition, as an example of a high-pressure fluid, gas and the like can be cited.

[0042] Back to Figure 1The temperature regulating unit 7 is a mechanism for regulating the temperature of the forming mold 2. The temperature regulating unit 7 regulates the temperature of the forming mold 2 to reduce the warping in the low-strength region E2. The temperature regulating unit 7 can quickly cool the expanded metal tube material 40 for quenching when the expanded metal tube material 40 contacts the forming surface of the forming mold 2 by cooling the forming mold 2 in the rapid cooling unit 12A, 11A. In addition, the temperature regulating unit 7 can regulate the metal tube material 40 to a temperature at which quenching does not occur when the expanded metal tube material 40 contacts the forming surface of the forming mold 2 by regulating the temperature of the forming mold 2 in the slow cooling unit 12B, 11B. The temperature regulating unit 7 includes: a flow path formed inside the lower mold 11 and the upper mold 12; a supply mechanism 37 that supplies a temperature regulating medium to the flow path and circulates it; and a control unit 8 that controls the supply mechanism 37.

[0043] The control unit 8 is a device for controlling the entire molding device 1. The control unit 8 controls the driving 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 tube material 40 using the molding die 2.

[0044] Specifically, the control unit 8 controls the timing of conveying from a conveying device such as a robot arm, so that the metal tube material 40 is arranged between the lower mold 11 and the upper mold 12 in an open state. Alternatively, the metal tube material 40 may be manually arranged between the lower mold 11 and the upper mold 12 by an operator. In addition, the control unit 8 controls the actuator of the holding unit 4 so that the metal tube material 40 is supported by the lower electrodes 26 on both sides in the longitudinal direction, and then the upper electrode 27 is lowered to clamp the metal tube material 40. In addition, the control unit 8 controls the heating unit 5 to electrically heat the metal tube material 40. As a result, a current flows in the axial direction of the metal tube material 40, and the metal tube material 40 itself generates heat due to Joule heat due to the resistance of the metal tube material 40 itself.

[0045] The control unit 8 controls the driving mechanism 3 so that the upper mold 12 descends and approaches the lower mold 11, thereby closing the molding die 2. On the other hand, the control unit 8 controls the fluid supply unit 6 to seal the openings at both ends of the metal tube material 40 with the nozzle 31 and supply fluid. As a result, the metal tube material 40 softened by heating is expanded and contacts the molding surface of the molding die 2. Moreover, the metal tube material 40 is formed into a shape identical to the shape of the molding surface of the molding die 2. In addition, in the case of forming a metal tube with a flange, after a part of the metal tube material 40 is allowed to enter the gap between the lower mold 11 and the upper mold 12, the mold is further closed to flatten the entered part to form a flange. If the high-strength region E1 of the metal tube material 40 contacts the molding surface, the molding die 2 cooled by the temperature regulating unit 7 is rapidly cooled, so that the metal tube material 40 is rapidly cooled.

[0046] The forming device 1 controls the cooling rate of the aluminum alloy during the solution treatment, so that the strength of the aluminum alloy after the aging treatment is different. The solution treatment is a process of forming the heated metal tube material 40 using the molds 11 and 12. The aging treatment is a process of artificial aging (painting and baking) after the metal tube 140 is formed using the forming device 1. The forming device 1 accelerates the cooling rate of the high-strength area E1 of the metal tube material 40 of the aluminum alloy by bringing the rapid cooling parts 11A and 12A into contact for rapid cooling. The forming device 1 slows down the cooling rate of the low-strength area E2 of the metal tube material 40 of the aluminum alloy by bringing the slow cooling parts 11B and 12B into contact for slow cooling. As a result, the forming device 1 makes the strength of the metal tube 140 of the aluminum alloy after the aging treatment different. The strength of the high-strength area E1 after the aging treatment is lower than that of the low-strength area E2. The control of the cooling rate is performed by locally heating the molds 11 and 12. Specifically, the slow cooling portions 11B and 12B of the molds 11 and 12 are locally heated.

[0047] refer to Figure 3 , the temperature regulating unit 7 is described in more detail. The temperature regulating unit 7 is provided with temperature regulating mechanisms 70 and 80 for regulating the temperature of the molding die 2. The temperature regulating mechanism 70 is provided inside the upper die 12, and regulates the temperature of the molding surface of the die 12. The temperature regulating mechanism 80 is provided inside the lower die 11, and regulates the temperature of the molding surface of the die 11. The temperature regulating mechanism 70 has a flow path 71 provided in the quenching portion 12A on both sides of the die 12. The flow path 71 cools the molding surface of the quenching portion 12A by allowing the cooling water from the supply mechanism 37 to flow. Furthermore, the temperature regulating mechanism 80 has a flow path 81 provided in the quenching portion 11A on both sides of the die 11. The flow path 81 cools the molding surface of the quenching portion 11A by allowing the cooling water from the supply mechanism 37 to flow.

[0048] Here, the slow cooling section 12B, 11B has a heating 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 rapid cooling sections 12A, 11A on both sides. The temperature regulating mechanism 70, 80 has a flow path 72, 82 provided in the normal mold block 12Bb, 11Bb. The same cooling water as the flow path 71, 81 of the rapid cooling section 12A, 11A is supplied to the flow path 72, 82. The heating mold block 12Ba, 11Ba is a block having a higher temperature than the rapid cooling section 12A, 11A. An insulating component 75 (or a gap) is provided between the rapid cooling section 12A, 11A and the heating mold block 12Ba, 11Ba. The temperature regulating mechanism 70, 80 has a flow path 73, 83 provided in the heating mold block 12Ba, 11Ba. The flow paths 73 and 83 allow a fluid having a higher temperature than the flow paths 71 and 81 to flow therethrough, so that the molding surfaces of the slow cooling portions 12B and 11B reach a higher temperature than the molding surfaces of the rapid cooling portions 12A and 11A. In addition, the temperature control mechanisms 70 and 80 may also include a heater or the like instead of the flow paths 73 and 83. Thus, the temperature control mechanisms 70 and 80 can control the cooling rate of the aluminum alloy during the solution treatment (during molding) to be slow by locally heating the slow cooling portions 11B and 12B.

[0049] Next, refer to Figures 5 to 10 , the reasons for the difference in strength of aluminum alloys and the control of the cooling rate of aluminum alloys are explained. Figure 5 and Figure 6 , the precipitation of alloying elements in aluminum is explained. Figure 5 This is a diagram for explaining the state of alloy elements in aluminum. Figure 5The graph shown shows the relationship between the concentration ratio of aluminum and alloying elements in the aluminum alloy and the temperature. In addition, the conceptual diagram shown on the right side of the graph shows the state of the metal structure of the aluminum alloy in each state. "1" in the graph indicates the state when the aluminum alloy (metal pipe 140) is subjected to a solid solution treatment. In "1", the aluminum alloy is in a "solid solution state" and the alloying elements are in a completely solid solution state. "2" indicates the state when the aluminum alloy is quenched. In "2", the aluminum alloy is in a "supersaturated solid solution state" and the precipitation phase should be more stable, but by rapidly cooling in the solid solution state, the alloying elements are still in a solid solution state. "3" indicates the state when the aluminum alloy is subjected to an aging treatment at a relatively low temperature after quenching. In "3", the aluminum alloy is in a state where a "metastable precipitation phase" is precipitated. "4" indicates the state when the aluminum alloy is subjected to an aging treatment at a relatively high temperature after quenching. In "4", the aluminum alloy is in a state where a "stable precipitation phase" is precipitated. "5" indicates the state when the aluminum alloy is slowly cooled. In "5", "stable precipitation phase" is precipitated during cooling by slow cooling. At this time, precipitation occurs not only inside the grains but also at the grain boundaries. For strengthening the aluminum alloy, it is effective to precipitate the precipitates densely inside the grains. Compared with the state of "5", the precipitation of the precipitates in the state of "4" is denser inside the grains.

[0050] in addition, Figure 6 An image showing the atomic arrangement in the precipitated state. Figure 6 (a) shows the image of the atomic arrangement in the solid solution. Figure 6 (b) Image showing the atomic arrangement in the intermediate phase. Figure 6 (c) shows an image of the atomic arrangement in a stable precipitated phase (equilibrium phase).

[0051] Next, refer to Figure 7 and Figure 8 , the processing time of aging treatment is explained. Figure 7 (a) is a graph showing the change in temperature of the aluminum alloy during solution treatment and aging treatment. Figure 7 As shown in (a), time t1 is the time before the aging treatment starts. Time t2 is the 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 inappropriately.

[0052] Figure 7The curve G1 in (b) is a curve diagram showing the size of precipitates of alloying elements in the aluminum alloy. The curve G2 is a curve diagram showing the strength of the aluminum alloy. The curve G3 is a curve diagram showing the number density of precipitates of alloying elements in the aluminum alloy. As shown in the curve G1, the size of the precipitates increases over time. On the other hand, as shown in the curve G2, the strength of the aluminum alloy reaches a peak strength at time t3 and then decreases. As shown in the curve G3, the number density of precipitates reaches a peak before time t3 and then decreases. Figure 8 Indicates the precipitation state at each time t1, t2, t3, and t4. At time t1, it becomes a supersaturated solid solution state. At time t2, a metastable precipitation phase precipitates. At time t3, a high-density stable precipitation phase precipitates. At time t4, a low-density stable precipitation phase precipitates. In this way, it can be seen as follows: if the aging treatment is performed to time t4, it becomes over-aged, the density of the stable precipitation phase decreases, and the strength of the aluminum alloy also decreases. Therefore, if the heating of the aging treatment is completed at time t3, which is the appropriate aging treatment time, the density of the stable precipitation phase increases, and the strength of the aluminum alloy increases.

[0053] Next, refer to Fig. 9 and Fig.10 , the high-strength region E1 of the aluminum alloy that is rapidly cooled in the rapid cooling sections 11A and 12A and the low-strength region E2 that is slowly cooled in the slow cooling sections 11B and 12B (reference Figure 3 ) is used to explain the precipitation state in FIG. Fig. 9 It is a graph showing the change in temperature of the aluminum alloy during solution treatment and aging treatment. The solid line graph A of the solution treatment represents the temperature of the high-strength region E1 that is subjected to rapid cooling, and the dotted line graph B represents the temperature of the low-strength region E2 that is subjected to slow cooling. During the heating process of the solution treatment, a heating holding time T is provided. When the heating of the solution treatment starts and rises to a specified temperature, the temperature is only 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 (about 500°C). Time t5 is the moment when cooling begins by contacting the aluminum alloy with the molds 11 and 12. The temperature change until time t5 is the same in any region E1 or E2. Moreover, the temperature change in the aging treatment is the same in any region E1 or E2. Time t6 is the time when the cooling in the low-strength region E2 ends. Time t7 is the moment when the heating temperature in the aging treatment is reached. Time t8 is the moment after the aging treatment ends.

[0054] Fig.10Represents the precipitation state at each time t5, t6, t7, and t8 of the high-strength region E1 that has been rapidly cooled and the low-strength region E2 that has been slowly cooled. In the high-strength region E1 that has been rapidly cooled, it becomes a supersaturated solid solution state until time t6. At time t7 when aging treatment is being performed, metastable precipitation phases precipitate. At time t8 after the aging treatment ends, high-density stable precipitation phases precipitate. On the other hand, in the low-strength region E2 that has been slowly cooled, precipitates have been precipitated in the stage after solution treatment and before aging treatment, i.e., at the stage of time t6. Moreover, precipitates are not only precipitated inside the grains, but also precipitates at the grain boundaries. Therefore, in the low-strength region E2, at time t8 after the final aging treatment, the number density of precipitates inside the grains becomes low, and the strength is reduced. Thus, the formed metal tube 140 has a high-strength region E1 (first portion) having a high number density of alloy element precipitates and a low-strength region E2 (second portion) having a lower number density of alloy element precipitates than the high-strength region E1.

[0055] Next, the effects of the molding device 1 according to the present embodiment will be described.

[0056] The forming device 1 forms an aluminum alloy metal tube material 40. For this aluminum alloy, after solution treatment by the forming device 1, thermal aging treatment is performed. The forming device 1 controls the cooling rate of the aluminum alloy during solution treatment. In the aluminum alloy, the strength obtained after aging treatment changes according to the cooling rate of the solution treatment. Therefore, the forming device 1 can form a portion with a fast cooling rate and a portion with a slow cooling rate in the aluminum alloy. In this way, if portions with different cooling rates are formed in the aluminum alloy, portions with different strengths can be obtained after aging treatment. As a result, a strength difference can be generated in the metal tube 140 of the aluminum alloy after forming.

[0057] The cooling rate can be controlled by locally heating the molds 11 and 12. At this time, if 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 the portions becomes slow. Thus, the cooling rate can be easily controlled.

[0058] The formed metal tube 140 may have a high-strength region E1 (first portion) having a high number density of alloy element precipitates, and a low-strength region E2 (second portion) having a lower number density of alloy element precipitates than the high-strength region E1. The high-strength region E1 has a high number density of precipitates and high strength. The low-strength region E2 has a low number density of precipitates and low strength. In this way, a strength difference can be generated between the high-strength region E1 and the low-strength region E2.

[0059] The heating holding time can be set during the heating process of the solution treatment. In this case, the time for the alloy elements to be dissolved can be ensured during the solution treatment. Thus, the strength difference generated by controlling the cooling rate can be easily set.

[0060] The present invention is not limited to the above-mentioned embodiments.

[0061] For example, the shape of the metal pipe after forming is not particularly limited, and it may be a metal pipe with a flange or a metal pipe without a flange.

[0062] Furthermore, the forming device may be any forming device that heats and quenches the metal material, and a forming device using a hot stamping method may also be used. In this case, the metal material becomes a plate. Other forming devices may also be used.

[0063] [Method 1]

[0064] A forming device is used to form aluminum alloy metal materials, wherein:

[0065] Control the cooling rate of aluminum alloy during solution treatment.

[0066] This makes a difference in the strength of the aluminum alloy after aging treatment.

[0067] [Method 2]

[0068] The molding device according to embodiment 1, wherein:

[0069] The cooling rate is controlled by locally heating the mold.

[0070] [Method 3]

[0071] The molding device according to embodiment 1 or 2, wherein:

[0072] The formed metal part includes a first portion having a high number density of alloy element precipitates and a second portion having a lower number density of alloy element precipitates than the first portion.

[0073] [Method 4]

[0074] A molding device according to any one of Modes 1 to 3, wherein:

[0075] A heating holding time is set during the heating process of the solution treatment.

[0076] [Method 5]

[0077] A metal part includes a first portion having a high number density of alloy element precipitates and a second portion having a lower number density of alloy element precipitates than the first portion.

Claims

1. A forming device for forming an aluminum alloy metal material, wherein: Control the cooling rate of aluminum alloy during solution treatment. The strength of aluminum alloys varies after aging treatment.

2. The molding device according to claim 1, wherein: The cooling rate is controlled by locally heating the mold.

3. The molding device according to claim 1, wherein: The formed metal part includes a first portion having a high number density of alloy element precipitates and a second portion having a lower number density of alloy element precipitates than the first portion.

4. The molding device according to claim 1, wherein: A heating holding time is set during the heating process of the solution treatment.

5. A metal part comprising a first portion having a high number density of alloy element precipitates and a second portion having a lower number density of alloy element precipitates than the first portion.

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