Molding device, molding system, and metal pipe

Abstract

This molding device molds a metal material with a first mold and a second mold. The first mold and the second mold have a quenching mode adjustment region for adjusting a quenching mode of at least a part of a region in the metal material. In the quenching mode adjustment region, one mold among the first mold and the second mold is provided with a quenching mechanism for only quenching the metal material, and the other mold is provided with a non-quenching mechanism for non-quenching of the metal material.

Description

Forming device, forming system, and metal pipe

[0001] The present disclosure relates to a forming apparatus, a forming system, and a metal pipe.

[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] The molded product formed by the above-described molding device is used to construct a predetermined structure. For example, the molded product may be joined to another member by welding. In this case, the entire molded product may be quenched to ensure strength, while the areas to be welded may be left as non-quenched portions. This reduces the strength of the non-quenched portions, making welding easier.

[0005] However, when a non-hardened portion is provided as described above, the strength of the entire circumference including the welded portion is reduced, and deformation is concentrated at that portion, which may result in insufficient component strength.

[0006] Therefore, an object of the present disclosure is to provide a molding device, a molding system, and a metal pipe that can improve the strength of molded products.

[0007] A molding device according to one aspect of the present disclosure is a molding device that molds a metal material using a first mold and a second mold, wherein the first mold and the second mold have a quenching pattern adjustment region that adjusts the quenching pattern of at least a portion of the metal material, and in the quenching pattern adjustment region, one of the first mold and the second mold is provided with a quenching mechanism that only quenches the metal material, and the other mold is provided with a non-quenching mechanism that does not quench the metal material.

[0008] In this molding device, the first and second molds have a quenching mode adjustment area that adjusts the quenching mode of at least a portion of the metal material. This makes it possible to adjust the strength of the molded product. Specifically, in the quenching mode adjustment area, one of the first and second molds is provided with a quenching mechanism that quenches the metal material, and the other is provided with a non-quenching mechanism that unquenches the metal material. The quenching mechanism can increase the strength of the metal material by quenching it. The non-quenching mechanism can form areas with partially lower strength depending on the application by not quenching the metal material. Therefore, in the molded product, strength can be reduced in areas where reduced strength is desirable, such as welds, while high strength can be maintained in other areas by quenching. As a result, the strength of the molded product can be improved.

[0009] The hardening mode adjustment region may be provided at a position corresponding to an end portion of the metal material in the longitudinal direction. Since the end portion of the molded product is likely to have a welded portion or the like formed there, it is possible to adjust the strength at that position.

[0010] The non-quenching mechanism may be constituted by a heating section provided in the other mold, thereby preventing rapid cooling of the molded product at the non-quenching mechanism, and thus preventing quenching.

[0011] The first and second dies may have a pair of main surfaces and a pair of side surfaces facing each other in the hardening mode adjustment region, and the non-hardening mechanism may non-harden one of the main surfaces and the pair of side surfaces. In this case, it is possible to improve the weldability between the side surfaces and the mating member.

[0012] A forming system according to one aspect of the present disclosure includes the forming device described above and a removal device that removes a surface of the formed product that faces the portion that is not hardened by the non-hardening mechanism. This makes it easier to insert a welding tool when forming a weld in the non-hardened portion by removing the facing surface.

[0013] A metal pipe according to one aspect of the present disclosure has a pipe portion having a pair of main surfaces and a pair of side surfaces, and one of the main surfaces of the pipe portion has a hardened portion and a non-hardened portion along the axial direction of the pipe portion, and the other main surface of the pipe portion has only a hardened portion along the axial direction. In this case, high strength can be ensured by reducing the strength of areas on one main surface of the metal pipe, such as welds, as non-hardened portions, and by making the other areas hardened portions. Furthermore, high strength can be ensured by configuring the other main surface only as hardened portions. As a result, the strength of the metal pipe can be improved.

[0014] According to the present disclosure, it is possible to provide a molding device, a molding system, and a metal pipe that can improve the strength of a molded product.

[0015] FIG. 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 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 has sealed a metal pipe material. FIG. 2(b) is a perspective view showing a molded product. FIG. 5(a) is a cross-sectional view taken along line Va-Va in FIG. 4, and FIG. 5(b) is a cross-sectional view taken along line Vb-Vb in FIG. 4. FIG. 5(b) is an enlarged perspective view of a hardening adjustment section of a molded product. FIG. 2(b) is a cross-sectional view of a hardening adjustment section of a molded product. FIG. 2(b) is a schematic diagram for explaining a molding die. FIG. 2(b) is a cross-sectional view of a hardening adjustment section of a molded product molded by a molding system according to a modified example. FIG. 2(b) is a cross-sectional view of a molding die.

[0016] 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.

[0017] 1 is a block diagram of a molding system 100 according to this embodiment. The molding system 100 is a system for molding a metal material. In this embodiment, a metal pipe material is used as the metal material. As a result, a metal pipe is molded as a molded product.

[0018] As shown in Fig. 1, the forming system 100 includes a forming device 1 and a removal device 101. The forming device 1 is a device that performs quenching by expansion forming a heated metal material. The forming device 1 forms a metal pipe by a forming method called STAF (Steel Tube Air Forming) forming.

[0019] The removing device 101 is a device that removes unnecessary portions from the molded product molded by the molding device 1. Details of the removing device 101 will be described later.

[0020] 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 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."

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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 .

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] The molded product 41 will be described with reference to Fig. 4. The molded product 41 shown in Fig. 4 is in a state after unnecessary portions have been cut off by the removal device 101. The molded product 41 has a molded main body portion 45 having a pipe portion 43 and a flange portion 44, an end region 46 on one end side in the longitudinal direction, and an end region 47 on the other end side.

[0034] The formed main body portion 45 is a portion that extends in the longitudinal direction with a substantially constant cross-sectional shape. As shown in Fig. 5(a), the pipe portion 43 is a hollow portion with a rectangular ring shape. The flange portion 44 is a plate-like portion that protrudes from both sides in the width direction of the pipe portion 43 by crushing a part of the metal pipe material 40. As shown in Fig. 5(b), the end region 47 on the other end side is formed into a flat plate shape by crushing the metal pipe material 40. On one side in the thickness direction of the end region 47, an air vent hole 48 is formed by the pipe wall protruding in an arched shape.

[0035] As shown in Figure 6, one end region 46 has a trapezoidal cross-sectional shape. The end region 46 has a main surface 46a corresponding to the upper side of the trapezoid, a main surface 46b corresponding to the lower side, and a pair of inclined side surfaces 46c and 46d. The main surface 46a is joined to another member and welded at a weld 70. A notch 71 is formed in the main surface 46b at a location facing the weld 70. The notch 71 is formed in a shape and range that allows a welding tool to access the weld 70 from the main surface 46b side. The notch 71 is formed so as to extend inward in the longitudinal direction from one end 41a of the molded product 41.

[0036] Next, the quenching mode of the formed product 41 will be described. As shown in Figure 4, the formed main body portion 45 of the formed product 41 becomes a quenched portion E1 that is subjected to normal quenching. In the quenched portion E1, quenching is performed over the entire circumference in a cross-sectional view. In the quenched portion E1, each portion in the circumferential direction is hardened by quenching. The end region 47 on the other side becomes a non-quenched portion E2 that is not quenched. In the non-quenched portion E2, each portion in the circumferential direction is softened by not quenching.

[0037] One end region 46 is a hardening-adjusted portion E3, where the hardening pattern has been adjusted. In the hardening-adjusted portion E3, a portion in a cross-sectional view is hardened, while another portion is not. As shown in FIG. 7 , the main surface 46a, where the welded portion 70 is formed, is a non-hardened portion 80 that is not hardened. The main surface 46b and side surfaces 46c and 46d opposite the main surface 46a are hardened portions 81. Of these, the central region of the main surface 46b is a cutout portion 82 that is removed to form the notch 71. The corners between the main surface 46a and the side surface 46c and the corners between the main surface 46a and the side surface 46d are transition sections 83, where the non-hardened portion 80 transitions to the hardened portion 81. The strength of the transition section 83 is intermediate between the strength of the non-hardened portion 80 and the strength of the hardened portion 81.

[0038] The configuration of the mold 2 for molding the molded product 41 whose quenching and non-quenching have been adjusted as described above will be described with reference to Figures 8 and 9. Figure 8 is a side view of the mold 2. As shown in Figure 8(a), the mold 2 has a quenching region 90 that forms a quenched portion E1 and a non-quenching region 91 that forms a non-quenched portion E2. In the quenching region 90, both molds 11 and 12 are provided with a quenching mechanism 93 that only quenches the metal pipe material 40. The quenching mechanism 93 does not have a corresponding portion of the metal pipe material 40 that is non-quenched. In the non-quenching region 91, both molds 11 and 12 are provided with a non-quenching mechanism 94 that non-quenches the metal pipe material 40.

[0039] The forming mold 2 has a quenching mode adjustment region 92 that forms a quenching adjustment portion E3. That is, the lower mold 11 (first mold) and the upper mold 12 (second mold) have quenching mode adjustment regions 92 that adjust the quenching mode of at least a portion of the metal pipe material 40. In this way, the quenching mode adjustment region 92 is provided at a position corresponding to an end portion in the longitudinal direction of the metal pipe material 40. In the quenching mode adjustment region 92, one mold 12 is provided with a quenching mechanism 93 that only quenches the metal pipe material 40, and the other mold 11 is provided with a non-quenching mechanism 94 that does not quench the metal pipe material 40.

[0040] The non-quenching mechanism 94 is constituted by a heating unit 95 provided in the molds 11 and 12. In the quenching mode adjustment region 92, the non-quenching mechanism 94 is constituted by a heating unit 95 provided in the other mold 11. The heating unit 95 may be, for example, a medium such as steam or hot water, a heater, or electromagnetic induction. The heating unit 95 heats the forming surface or the metal pipe material 40 itself, thereby preventing rapid cooling of the metal pipe material 40 during forming. This prevents quenching at the location corresponding to the non-quenching mechanism 94. However, the mechanism for constituting the non-quenching mechanism 94 is not limited to the heating unit 95. For example, a mechanism that partially prevents cooling of the cooling unit 7 in the molds 11 and 12 may be provided. The quenching mechanism 94 is constituted by not providing a heating unit 95 for the molds 11 and 12, but allowing the cooling function of the molds 11 and 12 to be exerted.

[0041] 9 , the heating section 95 of the non-quenching mechanism 94 is provided at a position of the lower mold 11 corresponding to the non-quenching section 80 on the main surface 46 a. The heating section 95 is not provided at positions of the mold 11 corresponding to the transition section 83 and the quenching section 81. In addition, the heating section 95 is not provided at the upper mold 12.

[0042] In addition, the main surface 46 b of the molded product 41 , which is the surface facing the non-hardening portion 80 by the non-hardening mechanism 94 , is removed by a removal device 101 .

[0043] The metal pipe serving as the molded product 41 has a pipe portion (a molded main body portion 45 and an end region 46) with a pair of main surfaces and a pair of side surfaces. In the end region 46 of the metal pipe serving as the molded product 41, a hardened portion 81 is provided on the upper main surface 46b, and a non-hardened portion 89 is provided on the lower main surface 46a. In addition, in the molded main body portion 45, hardened portions are provided on both the upper and lower main surfaces. Therefore, in the metal pipe serving as the molded product 41, the lower main surface of the pipe portion has hardened and non-hardened portions along the axial direction (longitudinal direction) of the metal pipe, and the upper main surface of the pipe portion has only a hardened portion along the axial direction. Note that the other end region 47 does not correspond to a pipe portion.

[0044] Next, the operation and effects of the molding system 100 and molding device 1 according to this embodiment will be described.

[0045] 8(c), a forming apparatus 200 according to a comparative example will be described. In the forming apparatus 200, non-hardened regions 91 are formed at positions corresponding to both end portions of the metal pipe material 40. In this case, non-hardened portions 80 are formed around the entire circumference of the end region 46. In this case, not only the locations where the welded portions 70 are formed but also the strength of the side surfaces 46c, 46d and the main surface 46b is reduced. Therefore, deformation is concentrated in the end region 46, resulting in a problem in which the formed product cannot be sufficiently strong.

[0046] On the other hand, in the molding apparatus 1 according to this embodiment, the molds 11 and 12 each have a quenching mode adjustment region 92 that adjusts the quenching mode of at least a portion of the metal pipe material 40. This allows for adjustment of the strength of the molded product 41. Specifically, in the quenching mode adjustment region 92, one mold 12 is provided with a quenching mechanism 93 that only quenches the metal pipe material 40, while the other mold 11 is provided with a non-quenching mechanism 94 that does not quench the metal pipe material 40 (see FIGS. 8(a) and 8(b)). The quenching mechanism 93 can increase the strength of the metal pipe material 40 by quenching it. The non-quenching mechanism 94 prevents quenching of the metal pipe material 40, allowing for the formation of portions with partially reduced strength depending on the application. Therefore, in the molded product 41, the strength can be reduced in areas where reduced strength is desirable, such as the welded portion 70, while high strength can be achieved in other areas by quenching. As a result, the strength of the molded product 41 can be improved.

[0047] The quenching mode adjustment region 92 may be provided at a position corresponding to an end in the longitudinal direction of the metal pipe material 40. Since the welded portion 70 and the like are likely to be formed at the end of the formed product 41, it becomes possible to adjust the strength at that position.

[0048] The non-quenching mechanism 94 may be constituted by a heating section 95 provided in the other mold 11. This prevents rapid cooling of the molded product 41 at the location of the non-quenching mechanism 94, making it possible to prevent quenching.

[0049] A forming system 100 according to one aspect of this embodiment includes the forming device 1 described above and a removal device 101 that removes the main surface 46b of the formed product 41 that faces the non-hardened portion 80 by the non-hardening mechanism 94. This makes it easier to insert a welding tool when forming a weld 70 in the non-hardened portion 80 by removing the facing main surface 46b.

[0050] A metal pipe according to one aspect of this embodiment has a pipe portion with a pair of main surfaces and a pair of side surfaces, and one of the main surfaces of the pipe portion has a hardened portion and a non-hardened portion along the axial direction of the metal pipe, while the other main surface of the pipe portion has only a hardened portion along the axial direction. In this case, high strength can be ensured by reducing the strength of areas on one main surface of the metal pipe, such as welds, as non-hardened portions, and by making the other portions hardened. Furthermore, high strength can be ensured by configuring the other main surface only as hardened portions. As a result, the strength of the metal pipe can be improved.

[0051] The present disclosure is not limited to the above-described embodiments.

[0052] For example, as shown in Fig. 8(b), quenching mode adjustment regions 92 may be provided in positions corresponding to both ends of the metal pipe material in the forming die 2. Also, a non-quenching mechanism 94 may be provided in the upper die 12, and a quenching mechanism 93 may be provided in the lower die 11.

[0053] 11 , the mold 11 and the mold 12 have a pair of opposing main surfaces 46 a, 46 b and a pair of side surfaces 46 c, 46 d in the hardening mode adjustment region 92. The non-hardening mechanism 94 may leave one of the main surfaces 46 a and the pair of side surfaces 46 c, 46 d unhardened. In this case, the weldability between the side surfaces 46 c, 46 d and the mating member can be improved.

[0054] Specifically, as shown in FIG. 10 , the main surface 46 a on which the welded portion 70 is formed becomes a non-hardened portion 80 that is not hardened. Furthermore, the side surfaces 46 c and 46 d become non-hardened portions 181. The lower corners 46 e and 46 f become non-hardened portions 183. The main surface 46 b opposite the main surface 46 a and the upper corners 46 g and 46 h become hardened portions 81 that are hardened. FIG. 11 is a cross-sectional view showing a molding die 2 for molding such a molded product 41. As shown in FIG. 11 , the non-hardening mechanisms 94 are provided not only at locations that contact the lower main surface 46 a, but also at locations that contact the lower corners 46 e and 46 f and the side surfaces 46 c and 46 d.

[0055] The shape of the molded product to be molded (the shape of the mold in the hardening mode adjustment region 92) is not particularly limited.

[0056] The configuration of the molding device 1 is not particularly limited, and may be modified from the structure shown in FIGS.

[0057] 1...forming device, 40...metal pipe material (metal material), 41...formed product (metal pipe), 92...quenching mode adjustment area, 93...quenching mechanism, 94...non-quenching mechanism, 95...heating section, 100...forming system, 101...removal device

Claims

1. A molding device for molding a metal material using a first mold and a second mold, wherein the first mold and the second mold have a hardening pattern adjustment area for adjusting the hardening pattern of at least a portion of the metal material, and in the hardening pattern adjustment area, one of the first mold and the second mold is provided with a hardening mechanism that only hardens the metal material, and the other mold is provided with a non-hardening mechanism that does not harden the metal material.

2. A forming apparatus as set forth in claim 1, wherein the hardening mode adjustment region is provided at a position corresponding to an end portion in the longitudinal direction of the metal material.

3. A molding apparatus as described in claim 1, wherein the non-hardening mechanism is constituted by a heating section provided in the other die.

4. A molding apparatus as described in claim 1, wherein the first mold and the second mold have a pair of main surfaces and a pair of side surfaces facing each other in the hardening pattern adjustment region, and the non-hardening mechanism non-hardens one of the main surfaces and the pair of side surfaces.

5. A molding system comprising: a molding device according to any one of claims 1 to 3; and a removal device for removing a surface of a molded product that faces a portion that has not been hardened by the non-hardening mechanism.

6. A metal pipe having a pipe section with a pair of main surfaces and a pair of side surfaces, one of the main surfaces of the pipe section having a hardened portion and a non-hardened portion along the axial direction of the pipe section, and the other main surface of the pipe section having only a hardened portion along the axial direction.

Images