Molding system, molding device, and molding method

Abstract

This molding system for molding a metal material comprises: a molding device for carrying out quenching by molding a heated metal material; and an aging treatment device for carrying out an aging treatment on a molded article molded in the molding device. In the molding device, the metal material is molded after a solution treatment and an artificial aging treatment have been carried out.

Description

Molding system, molding device, and molding method

[0001] The present disclosure relates to a molding system, a molding apparatus, and a molding method.

[0002] A conventional forming apparatus for forming a metal material is disclosed in Patent Document 1. This forming apparatus forms a part having a desired shape by pressing the metal material.

[0003] JP 2013-188793 A

[0004] Parts formed using the above-described forming apparatus are used to construct predetermined structures. For example, weight reduction in automobiles is being promoted to improve fuel efficiency and protect the environment. To this end, a solution-type material, such as a heat-treatable aluminum alloy, is heated, expanded, and then rapidly cooled by contact with a mold, thereby quenching the formed product. However, even if the formed product is subjected to aging treatment after forming, there are cases in which the desired strength cannot be obtained. On the other hand, there is a problem in that dimensional accuracy is reduced when the formed product is subjected to solution treatment or the like after forming.

[0005] Therefore, an object of the present disclosure is to provide a molding system, molding device, and molding method that can improve the strength of molded products while ensuring the dimensional accuracy of the molded products.

[0006] A forming system according to one aspect of the present disclosure is a forming system for forming a metal material, and includes a forming device that performs quenching by forming a heated metal material, and an aging treatment device that performs aging treatment on a formed product formed by the forming device, and the forming device forms the metal material after performing solution treatment and artificial aging treatment.

[0007] In this forming system, the forming device forms the heated metal material, thereby quenching it. The aging treatment device then performs aging treatment on the formed product formed by the forming device. In contrast, the forming device forms the metal material after solution treatment and artificial aging treatment. Therefore, even when rapid heating is performed in the forming device with a low heat input, the precipitates of the metal material enter a solid solution state. Therefore, the subsequent aging treatment device can achieve a state in which the precipitates are finely dispersed within the formed product (see, for example, Figure 8 ). This improves the strength of the formed product. Furthermore, since solution treatment or other treatments for improving strength are not required after forming in the forming device, a decrease in the dimensional accuracy of the formed product can be suppressed. As a result, the strength of the formed product can be improved while maintaining its dimensional accuracy.

[0008] The forming apparatus may be used to form a metal material after T6 treatment, which can improve the strength of the formed product after aging treatment.

[0009] The metal material may be an aluminum alloy, which has a low specific gravity and can reduce the weight of the molded product.

[0010] The molding device may mold a metal material heated to 400° C. or higher, thereby allowing the precipitates to be in a solid solution state.

[0011] The metal material may be a metal pipe material, and the forming device may perform expansion forming on the heated metal pipe material. In this case, unlike hot stamping of a plate material, generation of frictional heat between the die and the metal material can be suppressed, and seizure of the metal material to the die can be suppressed.

[0012] A forming apparatus according to one aspect of the present disclosure is a forming apparatus that performs quenching by forming a heated metal material, and forms a formed product in which the solid solution state of precipitates is maintained at a stage after forming and before aging treatment is performed.

[0013] This forming apparatus can form a formed product in which the precipitates remain in a solid solution state after forming but before aging treatment. Therefore, in the subsequent aging treatment, the precipitates can be finely dispersed within the formed product (see, for example, Figure 8). This improves the strength of the formed product. Furthermore, since there is no need to perform a solution treatment or the like to improve strength after forming with the forming apparatus, a decrease in the dimensional accuracy of the formed product can be suppressed. As a result, the strength of the formed product can be improved while maintaining its dimensional accuracy.

[0014] A forming method according to one aspect of the present disclosure is a forming method for forming a metallic material, in which the metallic material is subjected to a solution treatment and an artificial aging treatment, and then heated, formed, and quenched.

[0015] According to this molding method, it is possible to obtain the same functions and effects as the above-mentioned molding system.

[0016] According to the present disclosure, it is possible to provide a molding system, molding device, and molding method that can improve the strength of a molded product while ensuring the dimensional accuracy of the molded product.

[0017] 2( a ) is a block diagram showing a molding system according to an embodiment of the present disclosure; FIG. 2( b ) is a schematic diagram showing a molding apparatus 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 diagram showing a process image of Comparative Example 1; FIG. 2( a ) is a diagram showing the relationship between material temperature and strength and time in Comparative Examples 1 and 2; FIG. 2( b ) is a diagram showing the relationship between material temperature and strength and time in Comparative Example 3; FIG. 2( b ) is a diagram showing the relationship between material temperature and strength and time in Comparative Example 4; FIG. 2( b ) is a diagram showing the relationship between material temperature and strength and time in an Example; FIG. 2( a ) is a graph showing the relationship between Vickers hardness and aging time in Comparative Example 2 and an Example; FIG. 2( b ) is a graph showing the relationship between heating temperature and hardness when T6 treated material is subjected to artificial aging and natural aging after rapid heating and water cooling; FIG. 2( b ) is a graph showing an image of the relationship between thermal aging time, strength, precipitate size, and precipitate density of a precipitation-hardened aluminum alloy; FIG. 2( b ) is an image diagram showing the process of changes in precipitate size and precipitate density in a material during the manufacturing process of Comparative Example 1 and Comparative Example 2.

[0018] 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.

[0019] FIG. 1 is a block diagram of a forming system 100 according to this embodiment. The forming system 100 is a system for forming a metal material. In this embodiment, an aluminum alloy metal pipe material is used as the metal material. This results in a metal pipe being formed as a formed product. Note that the metal material is not limited to an aluminum alloy as long as it can be solution treated, and a nickel alloy or the like may also be used.

[0020] As shown in Fig. 1, the forming system 100 includes a forming apparatus 1 and an aging treatment apparatus 101. The forming apparatus 1 is an apparatus that performs quenching by expansion forming of a heated metal material. The forming apparatus 1 forms a metal pipe by a forming method called STAF (Steel Tube Air Forming) forming.

[0021] The aging treatment device 101 is a device that performs aging treatment on the metal pipe formed by the forming device 1. The aging treatment device 101 is configured, for example, by a furnace or the like that heats the metal pipe for a predetermined time immediately after forming. The formed metal pipe is removed from the forming device 1 and transported to the aging treatment device 101 by a transport mechanism or the like. The aging treatment device 101 performs heating at 100 to 170°C for 12 to 24 hours, for example.

[0022] Next, an example of the molding apparatus 1 will be described in detail with reference to Figures 2 and 3. Figure 2 is a schematic diagram of the molding apparatus 1 according to this embodiment. As shown in Figure 2, the molding apparatus 1 is an apparatus that molds 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 mold 2, a drive mechanism 3, a holding unit 4, a heating unit 5, a fluid supply unit 6, a cooling unit 7, and a control unit 8. In this specification, the 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."

[0023] The forming die 2 is a die for forming a metal pipe 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.

[0024] The drive mechanism 3 is a mechanism that moves at least one of the lower mold 11 and the upper mold 12. In Fig. 2, 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.

[0025] 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 forming mold 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 forming mold 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.

[0026] 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.

[0027] 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 forming 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 toward and away from 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 .

[0028] 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. 3(a) is a schematic side view showing the thermal expansion unit 150. Fig. 3(b) is a cross-sectional view showing the state when the nozzle 31 seals the metal pipe material 40.

[0029] 3A, 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.

[0030] 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.

[0031] Returning to Fig. 2, the cooling unit 7 is a mechanism for cooling the forming die 2. By cooling the forming die 2, the cooling unit 7 can rapidly cool the expanded metal pipe material 40 when it comes into contact with the forming surface of the forming die 2. The cooling unit 7 includes flow paths 36 formed inside the lower die 11 and the upper die 12, and a water circulation mechanism 37 that supplies cooling water to the flow paths 36 and circulates the water.

[0032] 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 cooling unit 7. The control unit 8 repeatedly performs the operation of molding the metal pipe material 40 in the forming die 2.

[0033] 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.

[0034] 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 forming 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 forming surface of the forming die 2. The metal pipe material 40 is then formed to conform to the shape of the forming surface of the forming 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 die is closed to crush the inserted portion and form a flange portion. When the metal pipe material 40 contacts the forming surface, it is quenched by the forming die 2, which is cooled by the cooling unit 7, thereby quenching the metal pipe material 40.

[0035] Next, the features of the forming system 100 and the forming apparatus 1 according to this embodiment will be described in detail. First, as Comparative Example 1 for the forming system 100 according to this embodiment, a typical hot forming process (e.g., hot stamping) using a precipitation-strengthened aluminum alloy plate material will be illustrated. FIG. 4 is a schematic diagram showing a process image in Comparative Example 1. As shown in FIG. 4 , in Comparative Example 1, the heating furnace 202 heats the plate material 210 at approximately 500°C. The plate material 210 is a material that has not been previously subjected to solution treatment, such as a cast material or an extruded material. Next, the forming apparatus 200 forms the plate material 210 into a formed product 211. At this time, the formed product 211 is quenched by rapid cooling. The treatment by the heating furnace 202 and the forming apparatus 200 corresponds to solution treatment. Next, the aging treatment apparatus 201 performs artificial aging treatment on the formed product 211.

[0036] FIG. 5(a) shows a graph GA1 showing the relationship between material temperature and time, and a graph GA2 showing the relationship between material strength and time, in Comparative Example 1. As shown in FIG. 5(a), in Comparative Example 1, a plate material 210 is heated to a temperature equivalent to a solution treatment by furnace heating, and then quenched and formed using a mold in a forming device 200. Furthermore, in Comparative Example 1, the desired strength is obtained by performing an artificial aging treatment (10 to 24 hours) called T6 treatment in an aging treatment device 201. In the figure, "PA1" indicates a location held at the solution treatment temperature for several minutes. "PA2" indicates a location where hot pressing is performed. "PA3" indicates a location where die quenching is performed. "PA4" indicates a location where artificial aging treatment is performed.

[0037] Next, Comparative Example 2 illustrates a case in which STAF forming (forming using the forming apparatus shown in Figures 2 and 3) is performed using a metal pipe material that has not been previously subjected to solution treatment, such as a cast material or an extruded material. Figure 5(b) shows a graph GB1 showing the relationship between material temperature and time, and a graph GB2 showing the relationship between material strength and time, in Comparative Example 2. In the figure, "PB1" is the location where electrical heating is performed. "PB2" is the location where expansion forming is performed. "PB3" is the location where artificial aging treatment is performed.

[0038] As shown in Figure 5(b), in the STAF forming process, the heating method is electrical heating, so there is no rapid heating or holding step when the heating temperature is reached. Therefore, as shown by "A" in the figure, sufficient solution treatment time is not ensured. Therefore, as shown in graph GB2, even after artificial aging treatment, the desired strength equivalent to T6 treatment is not obtained. In contrast, in the STAF forming process, the desired strength can be obtained by performing T6 treatment after electrical heating and forming. T6 treatment is a solution treatment of metal pipe material followed by artificial aging treatment. However, when such a process is adopted, the rapid cooling during solution treatment causes deformation due to differences in cooling rates between parts of the part, resulting in the problem of dimensional accuracy not being ensured.

[0039] Next, Comparative Example 3 illustrates hot stamping using a plate material after T6 treatment. In Comparative Example 3, the plate material is heated in a heating furnace. Next, the plate material is shaped in a forming device. The heating furnace and forming device shown in FIG. 4 may be used. FIG. 6 shows graph GF1, which shows the relationship between material temperature and time, and graph GF2, which shows the relationship between material strength and time, in Comparative Example 3. As shown in FIG. 6, in Comparative Example 3, the plate material is heated to 200 to 300°C by furnace heating, and then quenched and shaped using a mold in the forming device. In the figure, "PF1" indicates the location where heating is performed. "PF2" indicates the location where hot pressing is performed. "PF3" indicates the location where die quenching is performed. In Comparative Example 3, the low heating temperature results in high deformation resistance during forming, which imposes restrictions on the formed shape.

[0040] Next, Comparative Example 4 illustrates hot stamping using a solution-treated sheet. This sheet was not subjected to artificial aging treatment after solution treatment. In Comparative Example 4, the sheet was heated in a heating furnace. Next, the sheet was shaped in a forming device. Next, the desired strength was achieved by performing an artificial aging treatment (10 to 24 hours) called T6 treatment in an aging treatment device. The heating furnace, forming device, and aging treatment device shown in FIG. 4 may be used. FIG. 7 shows graph GH1, which shows the relationship between material temperature and time, and graph GH2, which shows the relationship between material strength and time, in Comparative Example 4. As shown in FIG. 7, in Comparative Example 4, the sheet was heated to 350 to 450°C in a furnace, then quenched and shaped using a mold in a forming device, and then artificial aging treatment was performed. In the figure, "PH1" indicates the location where heating was performed. "PH2" indicates the location where hot pressing was performed. "PH3" indicates the location where die quenching was performed. "PH4" is a portion where artificial aging treatment was performed.

[0041] In Comparative Example 4, the material used is solution-treated, so the material is in a supersaturated state (i.e., the material is thermally unstable). Depending on the storage conditions (time, temperature, etc.) of the material, natural aging progresses before press forming. This causes a problem of strength variation after press forming and artificial aging (see GH2x in phantom). Furthermore, in Comparative Example 4, if the heating temperature is set to a high temperature of 500°C or higher, frictional heat between the mold and the material during processing causes seizure to the mold.

[0042] In order to solve the problems of the comparative example described above, the forming system 100 according to this embodiment forms the metal pipe material 40 after solution treatment and artificial aging treatment in the forming device 1. The metal pipe material 40 after T6 treatment is formed in the forming device 1. By performing electrical heating, forming, and artificial aging treatment using the metal pipe material 40 after T6 treatment, the formed product of the forming system 100 can have strength equivalent to that of T6 treated material.

[0043] 8 shows a graph GK1 showing the relationship between material temperature and time, and a graph GK2 showing the relationship between material strength and time, in the forming system 100 according to the embodiment. "PK1" in the figure is the location where electrical heating is performed. Here, the heating temperature is 400 to 610°C. 610°C is a temperature below the melting temperature. "PK2" is the location where expansion forming is performed. "PK3" is the location where artificial aging treatment is performed.

[0044] FIG. 9(a) shows the aging characteristics when a material (as-cast or as-extruded material) that was not subjected to the T6 treatment was used as the forming material, as in Comparative Example 2. FIG. 9(b) shows the aging characteristics when an A6063 T6-treated material (Example) was used as the forming material, rapidly heated to a heating temperature of 520°C, water-cooled, and then subjected to artificial aging and natural aging. FIG. 9(a) shows graph GC1, which shows the natural aging characteristics, and graph GC2, which shows the artificial aging characteristics. FIG. 9(a) also shows reference line ST1, which shows the hardness after annealing (27.0 HV), and reference line ST2, which shows the hardness of the T6-treated material (82.4 HV). FIG. 9(b) also shows graph GD1, which shows the natural aging characteristics, and graph GD2, which shows the artificial aging characteristics. FIG. 9(b) also shows reference line ST2, which shows the hardness of the T6-treated material (82.4 HV).

[0045] As shown in Figure 9(a), the material without T6 treatment shows only a slight increase in hardness even after artificial aging. In contrast, as shown in Figure 9(b), the material with T6 treatment shows an increase in hardness with the artificial aging time, reaching a hardness equivalent to that of the T6 treated material after about 12 hours of artificial aging. In other words, it can be said that the material is solution treated even when rapidly heated.

[0046] Figure 10 is a graph showing the relationship between heating temperature and hardness when A6063 T6-treated material is rapidly heated to a heating temperature of 200 to 520°C, water-cooled, and then artificially and naturally aged. Graph GL in Figure 10 shows the relationship between heating temperature and hardness after water-cooling. At a heating temperature of 400°C, 16 hours of artificial aging can be achieved, and at a heating temperature of 520°C, 12 hours of artificial aging can be achieved to achieve a hardness equivalent to that of T6-treated material. The hardness achieved by artificial aging is higher than that achieved by natural aging for 7 days.

[0047] FIG. 11 is a graph showing the relationship between the thermal aging time of a precipitation-strengthened aluminum alloy and the strength (Graph GE1), precipitate size (Graph GE2), and precipitate density (Graph GE3). The upper part of the graph in FIG. 11 shows an image of precipitates in a material as the thermal aging time elapses. In the initial stage, the atoms constituting the precipitates are completely dissolved (State 1). As the thermal aging time progresses, the atoms constituting the precipitates gradually precipitate (State 2). As the thermal aging time continues, the atoms constituting the precipitates are completely precipitated (State 3). The number density and size of the precipitates also increase. As the aging time progresses and the strength peak is exceeded, the precipitate size becomes coarser than in State 3 (State 4). As the thermal aging time continues, the precipitates are gradually increasing in size while bonding with each other (State 5). Note that the number density decreases after the peak is exceeded (Ostwald ripening). In this way, by setting it to "State 3", the strength of the material can be increased.

[0048] Fig. 12 is an image diagram showing the process of change in precipitate size and precipitate density in the material during the manufacturing process of Comparative Example 1 and Comparative Example 2. In Figs. 6 to 8 and 12, the state of precipitates in the material during the processing step for each Comparative Example or Example is associated with State 1 to State 5 described in Fig. 11.

[0049] In Comparative Example 1, the material is solution-treated and artificially treated, resulting in finely dispersed precipitates (State 3). When heated, the precipitates dissolve due to sufficient heat input during the furnace heating process (State 0). After rapid cooling after forming, the precipitates do not precipitate due to rapid cooling, and the solid solution state is maintained (State 1). Finally, the precipitates disperse finely due to artificial aging (State 3). Note that when a material that has undergone T6 treatment is used as the material for hot stamping, the same structure as above is exhibited after the heating process.

[0050] In Comparative Example 2, the precipitates were large in the raw material state (State 5), and the electrical heating in the STAF forming process involved rapid heating and no temperature holding step. In other words, the heat input to the raw material was small, so the precipitates did not dissolve (State 5). Therefore, the structure did not change even after the forming, rapid cooling, and artificial aging steps (State 5).

[0051] As shown in Figure 6, in Comparative Example 3, the precipitates are finely dispersed in the raw material (T6-treated material plate) (State 3). The precipitate size increases during the heating process (State 4), and processing strain is imparted in the subsequent forming process. However, the strength of the material is lower than that of the T6-treated material due to the thermal energy imparted during heating.

[0052] As shown in Figure 7, in Comparative Example 4, precipitates are in solid solution in the material (solution-treated sheet) (State 1). In the heating process, the material is heated to a temperature of 350 to 450°C, and then immediately cooled in a mold, suppressing the formation of precipitates (State 2). Subsequent artificial aging treatment allows for strength equivalent to that of the T6 treatment to be obtained (State 3).

[0053] As shown in Figure 8, in the examples, the material used is a material that has undergone T6 treatment, so the precipitates are finely dispersed in the material (State 3). By heating to temperatures of 400 to 610°C in the heating process, the precipitates are solid-dissolved (State 1). After rapid cooling after forming, the precipitates are not precipitated by rapid cooling, and the solid-solution state is maintained (State 1). Finally, the precipitates are finely dispersed by artificial aging (State 3). This allows for strength equivalent to that of the T6 treatment to be obtained.

[0054] In the process shown in Fig. 8, the state immediately after forming by the forming apparatus 1 corresponds to "State 1" shown as "After forming and rapid cooling." Artificial aging is then performed in the aging treatment apparatus 101, resulting in a state "After artificial aging." As shown in Fig. 8, the forming apparatus 1 according to this embodiment forms a formed product in which the solid solution state of precipitates is maintained at the stage after forming and before aging treatment is performed.

[0055] Next, the functions and effects of the molding system 100, molding device 1, and molding method according to this embodiment will be described.

[0056] In this forming system 100, the forming device 1 performs quenching by expansion forming the heated metal material. The aging treatment device 101 then performs aging treatment on the formed product formed by the forming device 1. In contrast, the forming device 1 forms the metal material after solution treatment and artificial aging treatment. Therefore, even when rapid heating is performed with a low heat input in the forming device 1, precipitates in the metal material enter a solid solution state. Therefore, the subsequent aging treatment device 101 can achieve a state in which the precipitates are finely dispersed within the formed product (see, for example, "Example" in Figure 8). This improves the strength of the formed product. Furthermore, since solution treatment or other treatments for improving strength are not required after forming by the forming device 1, a decrease in the dimensional accuracy of the formed product can be suppressed. As a result, the strength of the formed product can be improved while maintaining its dimensional accuracy.

[0057] The forming apparatus 1 may be used to form a metal material after T6 treatment. In this case, the strength of the formed product after aging treatment can be improved. Furthermore, since the metal material after T6 treatment is in a thermally stable state, it is possible to reduce the variation in material quality during storage.

[0058] The metal material may be an aluminum alloy, which has a low specific gravity and can reduce the weight of the molded product.

[0059] The molding apparatus 1 may mold a metal material heated to 400° C. or higher, thereby making it possible for precipitates to be in a solid solution state.

[0060] The metal material may be a metal pipe material, and the forming apparatus 1 may perform expansion forming on the heated metal pipe material. In this case, unlike hot stamping of plate material, the generation of frictional heat between the die and the metal material can be suppressed, thereby suppressing the occurrence of seizure of the metal material on the die. For example, as shown in the forming apparatus 200 for hot stamping in FIG. 4, the die is pressed against the plate material to deform it, so frictional heat between the die and the metal material is large at corners, etc. In contrast, expansion forming forms the expanded metal pipe material by receiving it in the die, so the frictional heat is less than that in hot stamping.

[0061] The forming apparatus 1 according to this embodiment is a forming apparatus 1 that performs quenching by forming a heated metal material, and forms a formed product in which the solid solution state of precipitates is maintained at the stage after forming and before aging treatment is performed.

[0062] This forming apparatus 1 can form a formed product in which the precipitates remain in a solid solution state after forming but before aging treatment. Therefore, in the subsequent aging treatment apparatus 101, the precipitates can be finely dispersed within the formed product (see, for example, FIG. 8 ). This improves the strength of the formed product. Furthermore, since there is no need to perform a solution treatment or the like to improve strength after forming using the forming apparatus 1, a decrease in the dimensional accuracy of the formed product can be suppressed. As a result, the strength of the formed product can be improved while maintaining its dimensional accuracy.

[0063] A forming method according to one aspect of this embodiment is a method for forming a metal material, in which the metal material is subjected to solution treatment and artificial aging treatment, and then heated, formed, and quenched.

[0064] According to this molding method, the same functions and effects as those of the molding system 100 described above can be obtained.

[0065] The present disclosure is not limited to the above-described embodiments.

[0066] For example, in the above-described embodiment, the metal pipe material 40 that has undergone the T6 treatment is used as the metal pipe material 40 to be formed in the forming device 1. However, the treatment applied to the metal pipe material 40 before forming is not limited to T6 as long as it has undergone solution treatment and artificial aging treatment. For example, a metal pipe material 40 that has undergone solution treatment, cold working, and further artificial aging hardening treatment may be used.

[0067] The configuration of the forming apparatus 1 is not particularly limited, and may be changed from the configuration shown in Figures 2 and 3. For example, the forming apparatus may be a forming apparatus that hot stamps a metal material that has been subjected to solution treatment and artificial aging treatment. After forming, the metal material is subjected to aging treatment in an aging treatment device.

[0068] 1...forming device, 40...metal pipe material (metal material), 100...forming system, 101...aging treatment device

Claims

1. A forming system for forming a metal material, comprising: a forming device that performs quenching by forming the heated metal material; an aging treatment device for performing aging treatment on a molded product molded by the molding device, The forming system is configured such that the metal material is formed after solution treatment and aging treatment in the forming device.

2. The molding system according to claim 1 , wherein the molding device molds the metal material after T6 treatment.

3. The molding system of claim 1 , wherein the metallic material is an aluminum alloy.

4. The molding system according to claim 1 , wherein the molding device molds the metal material heated to 400° C. or higher.

5. The metal material is a metal pipe material, The molding system according to claim 1 , wherein the molding device expands and molds the heated metal pipe material.

6. A forming device that performs quenching by forming a heated metal material, A forming apparatus for forming a formed product in which a solid solution state of precipitates is maintained at a stage after forming and before aging treatment is performed.

7. A forming method for forming a metal material, comprising: A forming method in which metal material is heated after solution treatment and aging treatment, then formed and quenched.