WO2022050074A1

WO2022050074A1 - Molding mold

Info

Publication number: WO2022050074A1
Application number: PCT/JP2021/030453
Authority: WO
Inventors: 啓山内
Original assignee: 住友重機械工業株式会社
Priority date: 2020-09-04
Filing date: 2021-08-19
Publication date: 2022-03-10
Also published as: JP2022043699A

Abstract

This molding mold is for molding a heated metal material, wherein the molding mold includes: a first region which has a molding surface that comes into contact with the metal material when molding is performed, the molding surface being for cooling the metal material; and a second region which is formed on a section of the molding surface, and which is constituted by a low thermal-conductivity material having a lower thermal conductivity as compared to the first region.

Description

Molding mold

The present invention relates to a molding die.

Conventionally, as a molding die, the one described in Patent Document 1 is known. The molding apparatus provided with this molding has a fluid supply unit for supplying a fluid to the heated metal pipe material, and a molding mold for molding the molded product by bringing the expanded metal pipe material into contact with the molding surface. In this way, the heated metal material can be brought into contact with the molding die to perform molding and quenching at the same time.

Japanese Unexamined Patent Publication No. 2009-220141

Here, when the molding die described in Patent Document 1 described above is used, the molded product is quenched in the entire portion in contact with the molding die to have high strength. However, depending on the application, it may be required to partially reduce the strength of a part of the molded product. Therefore, it is required to easily adjust the strength in the molded product.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a molding die capable of easily adjusting the strength in a molded product.

The molding die according to one aspect of the present invention is a molding die for molding a heated metal material, and has a molding surface that comes into contact with the metal material during molding, and the molding surface is a first type that cools the metal material. It has a region of 1 and a second region formed of a low thermal conductivity material formed in a part of the molding surface and having a lower thermal conductivity than the first region.

The molding die has a molding surface that comes into contact with the metal material during molding. This molded surface has a first region for cooling the metal material. The first region can be quenched by cooling the metal material during molding. As a result, the strength of the portion of the molded product molded by the first region is increased. On the other hand, the molding surface has a second region formed of a part of the molding surface and made of a low thermal conductivity material having a lower thermal conductivity than the first region. The second region can have a lower heat removal rate for the metallic material than the first region. Therefore, in the second region, a portion having a low strength can be formed in the molded product because the quenching is not performed (or the quenching is weak). From the above, it is possible to easily adjust the strength in the molded product.

The thermal conductivity of the low thermal conductivity material may be 30% or less in ratio to the thermal conductivity of the material constituting the first region. In this case, the heat removal rate for the metal material can be sufficiently delayed, and it becomes easy to form a portion that is not quenched.

The Young's modulus of the low thermal conductivity material may have a deviation of 10% or less from the Young's modulus of the material constituting the first region. In this case, when the molded surface is stressed, the difference between the amount of deformation in the first region and the amount of deformation in the second region can be reduced.

The expansion rate of the low thermal conductivity material may have a deviation of 30% or less from the expansion rate of the material constituting the first region. In this case, when the molded surface receives heat, the difference between the amount of deformation in the first region and the amount of deformation in the second region can be reduced.

The metal material is a metal pipe material, and the molding surface may have a second region at a portion where the pipe portion is molded. As a result, a portion having a low strength can be formed in the pipe portion.

The metal material is a metal pipe material with a flange, and the molded surface may have a second region at a portion where the flange portion is molded. As a result, a portion having a low strength can be formed on the flange portion.

According to the present invention, it is possible to provide a molding die capable of easily adjusting the strength in the molded product.

It is a schematic diagram of the molding apparatus to which the molding die which concerns on embodiment of this invention is applied. It is a perspective view of the metal pipe after molding. It is sectional drawing which shows the state of molding by a molding die. It is sectional drawing which shows the state of molding by a molding die. It is a plan view of the lower mold. It is a graph which shows the thermal conductivity of each substance. It is a graph which shows Young's modulus of each substance. It is a graph which shows the expansion rate of each substance. It is a graph which shows the thermal shock resistance of each substance. It is a conceptual graph of the temperature transition of the metal pipe material for realizing quenching. It is sectional drawing of the molding mold which concerns on the modification.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, the same parts or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.

FIG. 1 is a schematic view of a molding apparatus 1 to which the molding die 2 according to the present embodiment is applied. As shown in FIG. 1, the molding apparatus 1 is an apparatus for forming a metal pipe having a hollow shape by blow molding. In this embodiment, the molding apparatus 1 is installed on a horizontal plane. The molding apparatus 1 includes a molding die 2, a drive mechanism 3, a holding unit 4, a heating unit 5, a fluid supply unit 6, a cooling unit 7, and a control unit 8. In the present specification, the metal pipe material 40 (metal material) refers to a hollow article before the completion of molding by the molding apparatus 1. The metal pipe material 40 is a pipe material of a steel grade that can be hardened. Further, among the horizontal directions, the direction in which the metal pipe material 40 extends at the time of molding may be referred to as "longitudinal direction", and the direction orthogonal to the longitudinal direction may be referred to as "width direction".

The mold 2 is a mold for molding a metal pipe 41 (molded product) from a metal pipe material 40, and includes a lower mold 11 and an upper mold 12 facing each other in the vertical direction. The lower mold 11 and the upper mold 12 are made of steel blocks. Each of the lower mold 11 and the upper mold 12 is provided with a recess for accommodating the metal pipe material 40. The lower mold 11 and the upper mold 12 are in close contact with each other (mold closed state), and each recess forms a space having a target shape in which the metal pipe material is to be formed. Therefore, the surface of each concave portion becomes the molding surface of the molding die 2. The lower mold 11 is fixed to the base 13 via a die holder or the like. The upper mold 12 is fixed to the slide of the drive mechanism 3 via a die holder or the like.

The drive mechanism 3 is a mechanism for moving at least one of the lower mold 11 and the upper mold 12. In FIG. 1, the drive mechanism 3 has a configuration in which only the upper mold 12 is moved. 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 meet each other, and a pull-back cylinder as an actuator that generates a force for pulling the slide 21 upward. A 22 is provided, a main cylinder 23 as a drive source for downwardly pressurizing the slide 21, and a drive source 24 for applying a driving force to the main cylinder 23.

The holding portion 4 is a mechanism for holding the metal pipe material 40 arranged between the lower mold 11 and the upper mold 12. The holding portion 4 holds the lower electrode 26 and the upper electrode 27 that hold the metal pipe material 40 on one end side in the longitudinal direction of the molding die 2, and the metal pipe material 40 on the other end side in the longitudinal direction of the molding die 2. A lower electrode 26 and an upper electrode 27 for holding are provided. The lower electrodes 26 and the upper electrodes 27 on both sides in the longitudinal direction hold the metal pipe material 40 by sandwiching the vicinity of the end portion of the metal pipe material 40 from the vertical direction. 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 a drive mechanism (not shown), and can move independently in the vertical direction.

The heating unit 5 is a mechanism for heating the metal pipe material 40 by energizing the metal pipe material 40. The heating unit 5 is the metal pipe material in a state where the metal pipe material 40 is separated from the lower mold 11 and the upper mold 12 between the lower mold 11 and the upper mold 12. 40 is heated by energization. The heating unit 5 includes the lower electrodes 26 and the upper electrodes 27 on both sides in the longitudinal direction described above, and a power supply 28 for passing a current through the electrodes 26 and 27 to the metal pipe material 40. The heating unit may be arranged at a place where the pre-process of the molding apparatus 1 is performed and may be heated outside the molding die 2.

The fluid supply unit 6 is a mechanism for supplying a 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 a high-pressure fluid to the metal pipe material 40 that has been softened at a high temperature by being heated by the heating unit 5, and expands the metal pipe material 40. The fluid supply unit 6 is provided on both ends of the molding die 2 in the longitudinal direction. The fluid supply unit 6 is a nozzle 31 that supplies fluid from the opening at the end of the metal pipe material 40 to the inside of the metal pipe material 40, and a drive that moves the nozzle 31 forward and backward with respect to the opening of the metal pipe material 40. A mechanism 32 and a supply source 33 for supplying a high-pressure fluid into the metal pipe material 40 via the nozzle 31 are provided. The drive mechanism 32 brings the nozzle 31 into close contact with the end of the metal pipe material 40 while ensuring the sealing property during fluid supply and exhaust, and separates the nozzle 31 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. Further, the fluid supply unit 6 may be the same device including the heating unit 5 together with the holding unit 4 having a mechanism for moving the metal pipe material 40 in the vertical direction.

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

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 an operation of molding the metal pipe material 40 with the molding die 2.

Specifically, the control unit 8 controls, for example, the transfer timing from a transfer device such as a robot arm, and puts the metal pipe material 40 between the lower mold 11 and the upper mold 12 in the open state. Deploy. Alternatively, the control unit 8 may manually arrange the metal pipe material 40 between the lower mold 11 and the upper mold 12. Further, the control unit 8 supports the metal pipe material 40 with the lower electrodes 26 on both sides in the longitudinal direction, and then lowers the upper electrode 27 to sandwich the metal pipe material 40, such as an actuator of the holding unit 4. Control. Further, the control unit 8 controls the heating unit 5 to energize and heat the metal pipe material 40. As a result, an axial current flows through the metal pipe material 40, and the electric resistance of the metal pipe material 40 itself causes the metal pipe material 40 itself to generate heat due to Joule heat.

The control unit 8 controls the drive mechanism 3 to lower the upper mold 12 and bring it closer to the lower mold 11 to close the mold 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 pipe material 40 with the nozzle 31 and supply the fluid. As a result, the metal pipe material 40 softened by heating expands and comes into contact with the molding surface of the molding die 2. Then, the metal pipe material 40 is molded so as to follow the shape of the molding surface of the molding die 2. When forming a metal pipe with a flange, a part of the metal pipe material 40 is inserted into the gap between the lower mold 11 and the upper mold 12, and then the mold is further closed. The entrance portion is crushed to form a flange portion. When the metal pipe material 40 comes into contact with the molding surface, the metal pipe material 40 is quenched by quenching with the molding mold 2 cooled by the cooling unit 7.

For example, a case where a high-strength metal pipe 41 is formed by quenching a metal pipe material 40 of a certain manganese boron steel will be described as an example. When cooling the material at 850 ° C., 200 ° C. is set as the cooling end temperature (obtained from a generally known CCM curve) as a temperature that does not enter the B transformation range regardless of time. At this time, since it is known that the hardness changes depending on the cooling rate, for example, by cooling the material at a cooling rate of −30 ° C./s, a metal pipe 41 having a hardness equivalent to Hv450 can be obtained. FIG. 10 is a conceptual graph of the temperature transition of the metal pipe material 40 for realizing such quenching. The control unit 8 heats the metal pipe material 40 to 850 ° C. or higher (T1). After heating, the metal pipe material 40 is exposed to the atmosphere until it comes into contact with the mold 2, so that it is cooled by natural heat dissipation (T2). Here, control is performed so that the temperature does not fall below 850 ° C. by the start of molding. By bringing the molding die 2 into contact with the metal pipe material 40, molding is performed and cooling is performed (T3). At this time, while the molding die 2 is used to remove heat at a cooling rate of −30 ° C./s or less, the control unit 8 controls to continue cooling until the cooling completion temperature becomes 200 ° C. or lower. After that, when the molding die 2 is opened and the metal pipe 41 is taken out, it switches to natural heat dissipation (T4).

Here, as described above, since the molding apparatus 1 can perform quenching of the metal pipe material 40 by quenching with the molding die 2, the metal pipe 41 that has been quenched as a whole is molded. Can be done. However, in the present embodiment, the molding apparatus 1 may form a portion of the metal pipe 41 that is not intentionally hardened (hereinafter, may be referred to as a “non-quenched portion 50”). can. Hereinafter, the non-quenched portion 50 will be described with reference to FIGS. 2 to 5.

FIG. 2 is a perspective view of the metal pipe 41 after molding. 3 and 4 are cross-sectional views showing a state of molding by the molding die 2. Note that FIG. 3A shows a cross-sectional view of the molding die 2 at a position (see FIG. 5) where the second region E2 exists in the longitudinal direction of the molding die 2. FIG. 3B shows a cross-sectional view of the mold 2 at a position (see FIG. 5) where the second region E2 does not exist in the longitudinal direction of the mold 2. 4 (a) is a cross-sectional view showing a state when the portion of FIG. 3 (a) is molded, and FIG. 4 (b) shows a state when the portion of FIG. 3 (b) is molded. It is sectional drawing which shows. FIG. 5 is a plan view of the lower mold 11.

The metal pipe 41, which is a molded product, will be described with reference to FIG. The metal pipe 41 includes a molded main body portion 45 having a pipe portion 43 and a flange portion 44, a held portion 46 on both ends in the longitudinal direction, and a gradual change portion 47 between the molded main body portion 45 and the held portion 46. , Equipped with. The molding main body portion 45 is a portion that becomes a final product by being laser-processed or the like. The pipe portion 43 is a hollow portion. The flange portion 44 is a multi-layered plate-shaped portion that protrudes from the pipe portion 43 by crushing a part of the metal pipe material 40. The held portion 46 is a cylindrical portion held by the electrodes 26 and 27. The nozzle 31 is inserted into the held portion 46. The gradual change portion 47 is a transition portion that changes from the shape of the held portion 46 to the shape of the molding main body portion 45.

Of these, a non-quenched portion 50 that is not hardened is formed in a part of one of the flange portions 44 in the width direction. The entire area of the metal pipe 41 other than the non-quenched portion 50 is the hardened portion 51. In FIG. 2, the portion with the gray scale is the non-quenched portion 50, and the portion without the gray scale is the hardened portion 51. In FIG. 2, the non-quenched portion 50 is formed in the vicinity of the central position in the longitudinal direction of one of the flange portions 44. The non-quenched portion 50 is formed on both sides of the flange portion 44 in the thickness direction.

As shown in FIG. 3, the

molds

11 and 12 have a molding surface 60 that comes into contact with the metal pipe material 40 during molding. The molding surface 60 has a pipe portion forming surface 61 for forming the pipe portion 43 and a flange portion forming surface 62 for forming the flange portion 44.

The procedure of molding using such a molding mold 2 will be described. As shown in FIGS. 3A and 3B, the control unit 8 closes the molding die 2 and supplies a fluid to the metal pipe material 40 by the fluid supply unit 6 to perform blow molding (primary). blow). In the primary blow, the control unit 8 forms the pipe portion 43 with the main cavity portion MC formed by the pipe portion forming surface 61, and causes the portion corresponding to the flange portion 44 to enter the sub-cavity portion SC formed by the flange portion forming surface 62. Then, as shown in FIGS. 4A and 4B, the control unit 8 forms the flange portion 44 by further closing the molding die 2 and further crushing the portion that has entered the subcavity portion SC. do. Next, the control unit 8 raises the upper mold 12 and separates it from the metal pipe material 40 to open the mold. As a result, the metal pipe 41 is formed.

As shown in FIGS. 3 and 4, the molding surface 60 has a first region E1 and a second region E2. The first region E1 is a region for cooling the metal pipe material 40. In the first region E1, the hardened portion 51 of the metal pipe 41 is formed by quenching the metal pipe material 40. The second region E2 is a region formed in a part of the molding surface 60 and composed of the low thermal conductivity material 64 having a lower thermal conductivity than the first region E1. The second region E2 forms the non-quenched portion 50 of the metal pipe 41 by preventing the metal pipe material 40 from being hardened.

As shown in FIGS. 3A and 4A of the molding surface 60 of the molding die 2, a second region E2 is formed on the flange portion molding surface 62 on one side of the

molds

11 and 12. .. Further, as shown in FIG. 2, the non-quenched portion 50 is formed only in a part of the central position in the longitudinal direction of the flange portion 44. Therefore, as shown in FIG. 5, the second region E2 is also formed only in a part of the central position in the longitudinal direction of the flange portion forming surface 62. As shown in FIG. 2, since the portion of the metal pipe 41 other than the non-quenched portion 50 is the hardened portion 51, the molded surface 60 is also the first region E1 except for the second region E2.

The second region E2 is configured by replacing the materials of the

molds

11 and 12 in the corresponding portions with the low thermal conductivity material 64. Specifically, a recess is formed in the flange portion forming surface 62, and the low thermal conductivity material 64 is arranged in the recess. At this time, of the low thermal conductivity material 64, the surface exposed to the outside becomes the second region E2 of the molded surface 60. In the flange portion forming surface 62, the low thermal conductivity material 64 is arranged so that a step does not occur at the boundary portion between the portion corresponding to the first region E1 and the portion corresponding to the second region E2. ..

Next, the low thermal conductivity material 64 will be described. Further, in the following description, zirconia ceramic is exemplified as an example of the low thermal conductivity material 64, and carbon steel is exemplified as the material of the

molds

11 and 12, that is, the material constituting the first region E1. There is. However, the material is not limited to these.

The thermal conductivity of the low thermal conductivity material 64 is preferably 30% or less in proportion to the thermal conductivity of the material constituting the first region E1. By setting the low thermal conductivity material 64 to these values, the heat removal rate in the second region E2 is sufficiently delayed, the HV value is reduced, and the portion where quenching is not performed is partially performed. It becomes possible to form. For example, as shown in FIG. 6, the thermal conductivity of carbon steel that can be used as a material for the dies 11 and 12 is equivalent to 40 ± 10 [W / (m / K)]. On the other hand, the thermal conductivity of the zirconia ceramic that can be used as the low thermal conductivity material 64 is equivalent to 4 ± 10 [W / (m / K)]. Therefore, the heat flux on the surface of the metal pipe material 40 in contact with the second region E2 can be limited to about 10% as compared with the first region E1, and the heat extraction rate can be locally delayed. can.

The Young's modulus of the low thermal conductivity material 64 preferably has a deviation of 10% or less from the Young's modulus of the material constituting the first region E1. For example, as shown in FIG. 7, the Young's modulus of carbon steel that can be used as the material of the dies 11 and 12 and the Young's modulus of the zirconia ceramic that can be used as the low thermal conductivity material 64 are almost the same value. Therefore, when the first region E1 and the second region E2 are stressed during molding, the amount of deformation of both is continuous, so that the amount of deformation is not large, such as damage to the parts of the low thermal conductivity material 64. It is possible to avoid damage caused by the uniformity.

The expansion rate of the low thermal conductivity material 64 preferably has a deviation of 30% or less from the expansion rate of the material constituting the first region E1. For example, as shown in FIG. 8, the coefficient of thermal expansion of carbon steel that can be used as the material of the dies 11 and 12 and the coefficient of thermal expansion of the zirconia ceramic that can be used as the low thermal conductivity material 64 are almost the same value. Therefore, when the first region E1 and the second region E2 receive heat during molding, the amount of deformation of both is continuous. Therefore, it is possible to avoid damage caused by the non-uniform deformation amount, such as damage to the parts of the low thermal conductivity material 64. Since zirconia ceramic has a characteristic that it is difficult to transfer heat, an average temperature deviation can occur between the

molds

11 and 12 and the low thermal conductivity material 64. Therefore, when the second region E2 is wide, it is preferable to take measures such as providing a gap by appropriately dividing the second region E2 so as not to cause damage due to the deviation of the average temperature.

The heat impact resistance of the low thermal conductivity material 64 is preferably high. For example, it is known that alumina-based ceramics, which are known as the most common industrial ceramics, are prone to cracking and breakage due to a sudden temperature difference. On the other hand, as shown in FIG. 9, the zirconia ceramic that can be used as the low thermal conductivity material 64 has a larger thermal shock temperature difference than the alumina-based ceramic. In particular, the zirconia ceramic has good crack resistance due to contact with a high-temperature material when the average temperature of the low thermal conductivity material 64 is low, such as at the start of operation of the molding apparatus 1.

Next, the action / effect of the molding die 2 according to the present embodiment will be described.

The molding die 2 has a molding surface 60 that comes into contact with the metal pipe material 40 during molding. The molded surface 60 has a first region E1 for cooling the metal pipe material 40. The first region E1 can be quenched by cooling the metal pipe material 40 at the time of molding. As a result, the strength of the hardened portion 51 formed by the first region E1 of the metal pipe 41 is increased. On the other hand, the molding surface 60 has a second region E2 formed of a part of the molding surface 60 and composed of a low thermal conductivity material 64 having a lower thermal conductivity than the first region E1. The second region E2 can have a lower heat extraction rate with respect to the metal pipe material 40 than the first region E1. Therefore, in the second region E2, a non-quenched portion 51 having a low strength can be formed in the metal pipe 41 by not quenching (or weakly quenching). From the above, the strength in the metal pipe 41 can be easily adjusted.

For example, among the skeleton members of an automobile, a rail part that connects the A pillar and the B pillar on the roof side will be described. Rail parts are high-strength parts, and B-pillars are also high-strength parts in general. Here, when the flange portions of both members do not have the non-quenched portion 50, the high-strength parts are joined by spot welding or the like, so that the welding quality may deteriorate. That is, in the body assembly process by spot welding, in a high-strength portion, the applied pressure of the spot welder may not be sufficient to obtain a sufficient load for plastically deforming the spot portion of the part to be welded. That is, depending on the total plate thickness to be overlapped, the current-carrying portion may not be sufficiently brought into close contact with the electrode pressing force (several hundred kilometers) of the spot welder. On the other hand, when the molding die 2 according to the present embodiment is used, the non-quenched portion 50 can be formed at the welded portion of the roof part and the B pillar. Therefore, spot welding can be easily performed, and the welding quality can be improved. The use of the metal pipe 41 on which the non-quenched portion 50 is formed is not limited to such a skeleton member of an automobile, and can be applied to various uses.

The thermal conductivity of the low thermal conductivity material 64 may have a ratio of 30% or less to the thermal conductivity of the material constituting the first region E1. In this case, the heat removal rate for the metal pipe material 40 can be sufficiently delayed, and it becomes easy to form a portion that is not quenched.

The Young's modulus of the low thermal conductivity material 64 may have a deviation of 10% or less from the Young's modulus of the material constituting the first region E1. In this case, when the molded surface 60 is stressed, the difference between the amount of deformation of the first region E1 and the amount of deformation of the second region E2 can be reduced.

The expansion rate of the low thermal conductivity material 64 may have a deviation of 30% or less from the expansion rate of the material constituting the first region E1. In this case, when the molding surface 60 receives heat, the difference between the amount of deformation of the first region E1 and the amount of deformation of the second region E2 can be reduced.

The metal material is a metal pipe material 40 with a flange, and the molding surface 60 may have a second region E2 at a position where the flange portion 44 is molded. As a result, a portion having a low strength can be formed on the flange portion 44.

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

In the above-described embodiment, a molding apparatus that supplies a high-pressure fluid to a heated metal pipe material to expand it and bring it into contact with a molding die to perform molding is exemplified. However, the molding apparatus to which the molding die of the present invention is applied is not particularly limited as long as it molds a heated metal material, and may be applied to a molding apparatus such as hot stamping.

The second region E2 is not limited to the form provided on the flange portion molding surface 62 of the molding die 2, and as shown in FIG. 11, the second region E2 may be provided on the pipe portion molding surface 61. That is, the metal material is the metal pipe material 40, and the molding surface 60 may have a second region E2 at a position where the pipe portion 43 is molded. As a result, a portion having a low strength can be formed in the pipe portion 43. Although the flange portion 44 is easy to weld, it requires a space corresponding to the width of the flange portion 44. On the other hand, by providing the second region E2 on the pipe portion 43 itself, it is possible to directly weld to the pipe portion 43 without limiting the width of the flange portion 44. When the non-quenched portion is provided in the pipe portion 43, the non-quenched portion may be formed in the vicinity of the end portion of the metal pipe material 40 in order to facilitate spot welding with other members.

2 ... Molding mold, 40 ... Metal pipe material (metal material), 60 ... Molding surface, 64 ... Low thermal conductivity material, E1 ... First region, E2 ... Second region.

Claims

A molding die that molds heated metal materials.
It has a molding surface that comes into contact with the metal material during molding, and has a molding surface.
The molded surface is
The first region for cooling the metal material and
A molding die having a second region formed on a part of the molding surface and made of a low thermal conductivity material having a lower thermal conductivity than the first region.
The molding die according to claim 1, wherein the thermal conductivity of the low thermal conductivity material has a ratio of 30% or less to the thermal conductivity of the material constituting the first region.
The molding die according to claim 1 or 2, wherein the Young's modulus of the low thermal conductivity material has a deviation of 10% or less from the Young's modulus of the material constituting the first region.
The molding die according to any one of claims 1 to 3, wherein the expansion rate of the low thermal conductivity material has a deviation of 30% or less from the expansion rate of the material constituting the first region.
The metal material is a metal pipe material.
The molding die according to any one of claims 1 to 4, wherein the molding surface has the second region at a portion where the pipe portion is molded.
The metal material is a metal pipe material with a flange.
The molding die according to any one of claims 1 to 4, wherein the molding surface has the second region at a portion where the flange portion is molded.