JP6493331B2 - Manufacturing method of press-molded products - Google Patents

Description

  The present invention relates to a technique for press-molding a metal plate into a hat-shaped cross-sectional component having a top plate portion curved at a predetermined radius of curvature in the longitudinal direction, a flange portion, and a vertical wall surface connecting the top plate portion and the flange portion. About.

In recent years, high-tensile materials have been applied to vehicle body structural parts in order to achieve both improvement in collision safety and weight reduction of automobile bodies. Since high tensile strength materials have high yield strength and tensile strength, defective molding such as springback becomes a problem when performing press molding.
As one of press-formed products used for vehicle body structural parts, for example, a top plate portion and a flange portion curved with a predetermined curvature radius in the longitudinal direction, such as a B pillar outer, and a vertical wall surface connecting the top plate portion and the flange portion, A hat-shaped cross-sectional component having the following. When such a part is press-molded, tensile stress is generated in the top plate portion at the bottom dead center of the molding, and compressive stress is generated in the flange portion, and a spring back (camber back) in the longitudinal direction of the component is generated due to the difference between these stresses. . When a high-tensile material is applied to such a component, there arises a problem that the stress difference at the bottom dead center is increased and the spring back is increased. Furthermore, since the variation in material strength increases in the high-tensile material, the variation in dimensional accuracy also increases. That is, material strength sensitivity increases.

There exists a technique described in patent documents 1-3 as a technique with respect to said subject.
In the manufacturing method of the press-formed product described in Patent Document 1, the top plate portion curved in the longitudinal direction and two side wall surfaces extending inward from the both ends along the longitudinal direction of the top plate portion are provided. By changing the curvature of the top plate portion in the previous process and the angle formed by the top plate portion and the side surface portion with respect to the molded product, the stress generated in the subsequent process is reduced and the spring back is suppressed.

In the manufacturing method of the press-formed product described in Patent Document 2, in the metal plate press-forming process that reaches the final press-formed product shape through a plurality of press-forming processes, the shape after the forming remains in the vicinity of the ridge line having a predetermined curvature. Residual stress is reduced by forming the part where tensile stress is generated with a smaller radius of curvature than the final shape in the previous process, and molding the part where residual compressive stress is generated with a larger radius of curvature than the final shape in the previous process. Counteracts and reduces springback.
The method for manufacturing a press-formed product described in Patent Document 3 is a method for generating a mold that allows for warpage that occurs during press forming, and the spring back is reduced by press forming using this expected shape.

JP 2011-206789 A JP 2007-190588 A JP 2007-286841 A

However, in the method for manufacturing a press-formed product described in Patent Document 1, only the curvature radius of the top plate portion is changed in a side view, so that the stress generated in the flange portion is not improved. For this reason, the spring back is not sufficiently suppressed for the ultra-high tensile material having a large amount of spring back, and the material strength sensitivity cannot be reduced.
In the method for manufacturing a press-formed product described in Patent Document 2, the magnitude of the curvature to be changed changes depending on the region where compressive stress or tensile stress is generated, so that the design of the mold becomes complicated.

The manufacturing method of the press-formed product described in Patent Document 3 cannot reduce the residual stress at the press bottom dead center to 0 (zero), so the material strength sensitivity is not reduced.
The present invention is to solve the above-mentioned conventional problems, and even when a high-tensile material is used, the spring back can be accurately reduced, and a highly accurate hat-shaped cross-sectional curved shape close to the target part shape is obtained. It is an object of the present invention to provide a method for producing a press-formed product excellent in shape freezing property and material strength sensitivity capable of obtaining a part.

In order to solve the problem, according to the method for manufacturing a press-formed product of one aspect of the present invention, the top plate portion and the flange portion are continuous in the width direction via the side wall portion, and the top plate portion and When the metal plate is press-molded into a product shape having a hat-shaped cross section that is convexly or concavely curved toward the top plate side along the longitudinal direction, the top plate portion and the flange portion First, an intermediate part is manufactured by press-molding a part along the longitudinal direction with a first die into a part shape having a hat-shaped cross section having a second radius of curvature smaller than the radius of curvature of the product shape. And a second step of press-molding the intermediate part into the product shape with a second die, and a plurality of the metal plates assumed to be press-molded using the same die The metal plate assumed to have the highest material strength The shape of the part after the spring back is generated after performing the press forming of the first step and the second step under the material conditions of the representative metal plate and removing it from the second die. The simulation analysis is performed so as to approach the product shape, and the configuration of the first mold is set.
As the simulation analysis, a finite element method or other known analysis methods may be applied.

Here, since the metal plate is manufactured with a variation within a predetermined range, there is variation in the material strength of the metal plate to be pressed.
On the other hand, according to the aspect of the present invention, the first mold is used under the condition of the metal plate assumed to have the highest material strength among the conditions of the metal plate assumed to be press-formed with the same mold. Optimize your design.

As a result, even when the material strength of a plurality of metal plates processed with the same mold varies, a part with high dimensional accuracy can be obtained, leading to an improvement in yield. Furthermore, when using a hat-shaped cross-sectional part to make a vehicle body structural part, it is possible to easily assemble the part.
Here, at least a spring in the longitudinal direction of the component is produced by press-molding with a first mold into a component shape having a hat-shaped cross section having a second curvature radius smaller than the curvature radius of the product shape, thereby producing an intermediate component. Backing can be suppressed. The first mold may be configured by designing to suppress the spring back in the component cross-sectional direction.

It is a schematic diagram which shows an example of a product shape, (a) is a perspective view, (b) is a side view. It is the schematic explaining the springback in hat-shaped cross-section components. It is a figure which shows the process of the manufacturing method of the press-formed product which concerns on embodiment based on this invention. It is a schematic diagram which shows an example of a metal mold | die, (a) is a figure which shows a 1st metal mold | die, (b) is a 2nd metal mold | die. It is a figure which shows the hat-shaped cross-section component curved in the longitudinal direction in an Example.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
FIG. 1 shows an example of a product shape obtained by press molding, which is the purpose of this embodiment. In this example, the main body 4 has a top plate portion 1 and a flange portion 2 that are formed into a hat-shaped cross-section component in which the top plate portion 1 and the flange portion 2 are continuous in the width direction via the side wall portion 3. Is curved so as to be convex toward the top plate 1 along the longitudinal direction. In FIG. 1, the curved portion is formed to be biased to the left side. The curvature of the curvature along the longitudinal direction formed in the top plate portion 1 and the flange portion 2 may be the same, but is different in the present embodiment.

  Further, in the product shape of the present embodiment, the projecting portions 5 are continuous with both ends in the longitudinal direction of the top plate portion 1. Since the width of each overhanging portion 5 is larger in the width direction than the width of the top plate portion 1, the top plate portion on the end side in the longitudinal direction of the product shape in the top view is L-shaped or T-shaped. It has become. FIG. 1 illustrates a T shape. Further, the lower end portion of the vertical wall portion 6 is continuous with the longitudinal end portion of the flange portion 2. The vertical wall portion 6 rises to the top plate portion 1 side, and its upper end continues to the overhang portion 5. With the shape described above, the main body 4 having a curved end portion extends in the vertical direction with respect to the vertical wall 6. That is, the vertical wall portion 6 rises so as to face the longitudinal direction of the main body portion 4. A shape in which the vertical wall portion 6 exists only on one side in the longitudinal direction may be used.

However, in the manufacturing method of the press-formed product based on this invention, even if it is a product shape without the overhang | projection part 5 and the vertical wall part 6, it is applicable. Moreover, even if the top-plate part 1 and the flange part 2 are concave curved shapes at the top-plate part 1 side along a longitudinal direction, it is applicable. Further, the present invention is applicable even when the longitudinal curvature is formed in a part of the entire length in the longitudinal direction of the component.
Furthermore, even when a concave or convex shape for the purpose of reinforcement or the like is formed on the top plate portion 1, it can be applied. In this case, the concave or convex shape may be formed on the press surface portion of the mold facing the top plate portion 1.
As the metal plate, an ultra high tensile material of 590 MPa or more is targeted, but a steel plate, an aluminum plate, or the like may be used. Moreover, the magnitude | size of the curvature radius of the top-plate part 1 and the flange part 2 may differ in an intermediate | middle part and product shape.

  Here, it is a hat-shaped cross-sectional component in which both sides in the width direction of the top plate portion 1 are continuous to the flange portion 2 through the side wall portion 3 so as to protrude toward the top plate portion 1 side along the longitudinal direction. When a metal plate made of a blank material is formed on a curved hat-shaped cross-sectional component by a single press, as shown in FIG. 2A, tensile residual stress is generated in the top plate portion 1 of the curved portion, and the flange Compressive residual stress is generated in part 2. Then, by removing the parts from the press mold and releasing these stresses, a spring back (camber back) along the longitudinal direction of the parts as shown in FIG. 2B is generated. At the same time, as shown in FIG. 2C, a springback in the component cross-sectional direction also occurs at the same time. At this time, as the material strength of the metal plate increases, the residual stress increases and the amount of spring back tends to increase. That is, the amount of springback differs depending on the material strength. In particular, when a high tensile material of 590 MPa or more is employed, the springback becomes large. For this reason, in the high tensile strength material of 590 MPa or more, there is a possibility that the variation in the dimensional accuracy of the product increases as the variation in the material strength increases.

On the other hand, in the manufacturing method of the press-formed product of the present embodiment, as shown in FIG. 3, the first step and the second step are performed as press processing for forming a flat metal plate into the product shape. Process. By making the pressing process for manufacturing a molded product into a multi-step process of two stages, it is possible to improve dimensional accuracy such as suppression of spring back of the product.
Here, it has trim processing (not shown) which trims the flange outer periphery. The trim processing may be performed before the first step, may be performed between the first step and the second step, or may be performed after the second step. In the present embodiment, the case where trim processing is performed after the press processing in the first step will be described. In this case, the intermediate part is a part in a state where trimming of the outer periphery of the flange is performed.

The first step is a step of press-molding the metal plate 10 (blank material) into an intermediate part having a hat-shaped cross section using a first mold as shown in FIG. Reference numeral 11 denotes a punch, reference numeral 12 denotes a lower mold, and reference numeral 13 denotes a wrinkle pressing member.
The second step is a step in which the intermediate part 20 produced in the first step is used in a second mold as shown in FIG. Reference numeral 21 denotes a punch, reference numeral 22 denotes a lower mold, and reference numeral 23 denotes a wrinkle pressing member.

The product shape is such that at least the top plate portion 1 and the flange portion 2 are continuous in the width direction via the side wall portion 3 and the top plate portion 1 and the flange portion 2 are on the top plate portion 1 side along the longitudinal direction. It has a hat-shaped cross section curved with a predetermined curvature.
In the present embodiment, both the spring back in the component cross-sectional direction and the spring back in the component longitudinal direction that occur when the first mold is press-molded into the product shape of the metal plate 10 without performing the first step. It is designed to have a mold shape for forming the intermediate part 20 having a controllable shape.

The design of the mold shape in this embodiment is a first design that determines a mold shape that can suppress spring back in the component cross-sectional direction, and a first design that can suppress spring back in the component longitudinal direction. This is performed through two stages of the second design for correcting the determined mold shape, and the final mold shape (mold configuration) of the first mold is determined.
For example, the first design is performed as follows.

In the first design, for a target hat shape, a die shape capable of suppressing springback in the component cross-sectional direction is determined for a straight hat-shaped cross-sectional shape that is not curved along the longitudinal direction. To do.
By assuming a straight hat-shaped cross-section with no curvature along the longitudinal direction of the part, it is possible to ignore the influence of the spring opening in the longitudinal direction of the part (spring back in the sectional direction of the part) and open the wall. Only the influence can be set on condition. And if a wall opening is suppressed by a straight shape, even if it is a curved shape along a longitudinal direction, it will become possible to suppress a wall opening.

Here, the setting of the mold shape capable of suppressing the spring back in the component cross-sectional direction may be determined by adopting a conventionally proposed method. The wall opening occurs due to punch shoulder angle change (change in angle of the connecting portion between the top plate portion 1 and the side wall portion 3) and wall warp. Examples of the design of the mold for suppressing the wall opening include the following methods.
That is, as a method of suppressing the spring back in the component cross-section direction using the punch shoulder angle change, for example, a method of determining the die shape so as to suppress the angle change by chamfering the punch shoulder 11a, There is a method of setting the mold shape so as to be bent twice with different shapes. In these methods, the mold shape is determined so as to reduce the angle change by canceling out the spring back component and the spring go component generated at the punch shoulder 11a.

  Moreover, as a method of reducing wall warpage and suppressing spring back in the component cross-sectional direction, there is a method of setting a mold shape so as to control the wrinkle pressing force. In the region where the wrinkle pressure is low, reverse bending occurs in the vertical wall and the wall warpage is reduced, but if it is too low, wrinkles may occur in the flange portion. On the other hand, even when the wrinkle pressing force is increased, the wall warpage is reduced because the tension is applied, but if the high wrinkle pressing force continues to be applied, cracking may occur.

In the first design, as a method of suppressing the spring back in the component cross-sectional direction, a mold shape that suppresses both the punch shoulder angle change and the wall warp may be designed.
In the second design, the mold shape determined in the first design is corrected to a shape that can suppress the spring back in the component longitudinal direction.
That is, after finding the spring back suppression condition of the cross section of the component as described above, a countermeasure for camber back is implemented.

  In order to reduce this camber back (spring back in the longitudinal direction of the component), in this embodiment, the top plate portion 1 and the flange in the intermediate component 20 are set straight along the longitudinal direction of the component in the first design. In the second design, the radius of curvature of the curvature along the part longitudinal direction of the surface pressing part 2 is modified to be smaller than the radius of curvature of the curvature along the longitudinal direction of the part in the product shape.

  Here, the top plate portion 1 and the flange portion 2 of the intermediate part 20 after being press-molded in the first step using the first die designed as described above and released from the first die. The radius of curvature along the longitudinal direction of the part is slightly larger than the radius of curvature set in the first mold by, for example, springback. Therefore, the curvature radius (second curvature radius) of the top plate portion 1 and the flange portion 2 generated by the spring back after the first step is smaller than the curvature radius of the molded product that is the product shape. The radius of curvature along the longitudinal direction of the part of the first mold is designed.

In designing the first mold as described above, a finite element method or other simulation analysis is performed to set the configuration of the first mold.
At this time, in the present embodiment, the material condition of the metal plate set as the analysis condition is determined as follows. That is, in a plurality of metal plates 10 that are assumed to be press-molded using the same mold, a metal plate that is assumed to have the highest material strength is used as a representative metal plate, and material conditions of the representative metal plate Is the material condition applied to the analysis.

  In the simulation analysis described above, the spring back is generated at least in the longitudinal direction after the first metal plate and the second metal plate are press-formed and removed from the second metal mold. Analysis is performed so that the subsequent part shape becomes the product shape or approaches the product shape, and the configuration of the first mold is set. Although the amount of springback varies depending on the material strength, the surface that presses at least the curvature of the top plate portion 1 and the flange portion 2 in consideration of the amount of springback that occurs when the material is taken out of the mold in consideration of the material strength. The configuration of the first mold is set by designing the curvature radius of the curvature in the longitudinal direction of the part to be smaller than the curvature radius of the curvature in the longitudinal direction of the part in the product shape. It is preferable to set the configuration of the first mold so that the analysis is performed using the material conditions of the representative metal plate and the spring back in the component cross-sectional direction is also suppressed.

Here, since the metal plate 10 is manufactured while allowing variation of a predetermined tolerance, there is variation in the material strength of the metal plate 10 to be pressed.
As the material strength of the representative metal plate, a metal plate having the highest material strength among the plurality of metal plates 10 that are actually press-formed may be employed. In addition, it is estimated that the variation is almost normally distributed. Moreover, you may set the upper limit allowable intensity | strength of the material intensity | strength set when manufacturing the metal plate 10 as material intensity | strength of a typical metal plate.

  Here, the upper limit value of the variation at each intensity level TS can be expressed by, for example, a value obtained by adding 10% of each intensity (TS + 0.1 × TS) = 1.1 TS, and the range of the upper limit value is, for example, 1.1 TS Is set within a range of ± 3%. Therefore, based on the material strength of the representative metal plate obtained as described above, the material strength selected from the range of ± 3% is adopted as the material strength of the representative metal plate used in the analysis. Also good.

  After the first step, by forming the curvature radius of the top plate portion 1 and the flange portion 2 of the intermediate part 20 after the spring back to be equal to or less than the curvature radius in the product shape, in the second step, In the wrist-like molding, a small compressive stress is generated in the top plate portion 1 and a small tensile stress is generated in the flange portion 2 by the Bauschinger effect. Thereby, the stress difference between the top plate portion 1 and the flange portion 2 is reduced, the amount of springback is reduced, and the sensitivity of the material strength can be improved when the material strength is shaken.

  The spring back in the component cross-sectional direction and the camber back (spring back in the longitudinal direction of the component) are linked, but in this embodiment, the mold is first designed so as to reduce the spring back in the component cross-sectional direction. Thus, it is possible to manufacture a mold that minimizes the fluctuation of the wall opening when the camber back countermeasure is implemented. If the camber back countermeasure is implemented first, the camber back will occur again when the spring cross section countermeasure for the component cross section is implemented next, increasing the pressing process and complicating the die design.

  However, when determining the amount of change in the curvature of the intermediate part 20 with respect to the product shape, in the first step, the spring back calculation of the hat-shaped cross-sectional part curved with the curvature radius in the product shape is performed, and the top plate after the spring back is performed. When the radius of curvature of the portion 1 is R1 ′, the ratio of the product shape with the radius of curvature R1o of the top plate portion 1 is set within a range of 0.70 ≦ (R1 ′ / R1o) <1.00. Is preferred.

Similarly, when the radius of curvature 2 of the flange portion of the intermediate part 20 with respect to the product shape is R2 ′, the ratio of the radius of curvature R2o of the flange 2 in the product is 0.70 ≦ (R2 ′ / R2o) <1. It is preferable to set within the range of 00.
Here, when (R1 ′ / R1o) and (R2 ′ / R2o) are smaller than 0.7, an excessive compressive stress is applied to the top plate 1 at the bottom dead center of the mold in the second step. Excessive tensile stress is generated in 2 and there is a possibility that spring go is generated in the molded product. On the other hand, when (R1 ′ / R1o) and (R2 ′ / R2o) are larger than 1, the top plate portion 1 has a tensile stress and the flange portion 2 has a compressive stress at the bottom dead center of the mold in the second step. The remaining spring back may not be sufficiently suppressed.

Further, the longitudinal line lengths of the top plate portion 1 and the flange portion 2 in the intermediate component 20 manufactured in the first step are respectively the longitudinal line lengths of the top plate portion 1 and the flange portion 2 in the product shape, respectively. It is preferable to set the first mold shape so as to have the same value.
The same line length can be obtained by adjusting the line length of the vertical wall portion 6 that connects the flange portion 2 and the overhang portion 5, for example.

Moreover, in this embodiment, after the said press molding in a 1st process, the trim processing of a flange outer periphery is given. For the trim processing, a known processing method such as shearing or laser cutting may be employed.
Moreover, the 2nd metal mold | die used for a 2nd process is set to the metal mold | die shape which has a product shape or a shape approximate to it.

Here, it is preferable that draw or foam molding is applied in the first step, and that the second step is a re-striking step of molding into a product shape.
Further, each radius of curvature after the springback generated in each of the intermediate parts 20 may be obtained by calculation by performing a CAE analysis or other simulation analysis by a computer, or a test product is actually manufactured and measured. You may ask.

(Operation other)
In the first step, the metal plate 10 is press-molded into the intermediate part 20 using the first mold designed as described above.
Next, in the second step, the intermediate part 20 is press-molded using the second mold described above to produce a product-shaped part.

In the present embodiment, the first mold that has been modified so as to suppress the spring back (camber back) in the longitudinal direction of the component after first determining the shape in which the spring back in the component cross-sectional direction is suppressed. The intermediate part 20 is produced.
Here, in the present embodiment, when designing the mold, the design is performed so that the springback is suppressed, but the analysis at that time is also performed by setting the material conditions of the target metal plate. . However, since the material strength of the metal plate that is actually press-formed varies, depending on the material setting conditions, the dimensional accuracy is not always good across all products manufactured by press-forming with the same mold.

  The inventors have examined this point, and have found that the higher the material strength, the greater the variation in dimensional accuracy in the product. Based on this knowledge, the mold configuration is designed with the material strength of the metal plate assumed to be the highest among the plurality of metal plates press-formed by the same mold as the material conditions. Thereby, in this embodiment, the dimensional accuracy of the spring back suppression in the whole product press-molded with the same metal mold | die improves.

  From the above, in the present embodiment, there is a variation in material strength, and even when an ultra-high tensile material is used, the spring back can be reduced with high accuracy, and further, the material strength is highly sensitive and highly accurate. A hat-shaped curved part can be obtained. That is, even when the material strength varies depending on the metal plate 10 to be processed, parts with high dimensional accuracy can be obtained, leading to an improvement in yield. Furthermore, when using a hat-shaped cross-sectional part to make a vehicle body structural part, it is possible to easily assemble the part.

In order to confirm the effect of reducing the spring back by the manufacturing method of the press-formed product according to the present invention, press forming analysis and spring back analysis by the finite element method (FEM) were performed, and the results will be described below.
In this embodiment, the first mold used in the first step and the second used in the second step are intended for the case of press-molding a hat-shaped cross-sectional component curved in the longitudinal direction shown in FIG. Multiple analyzes were performed by changing the ratio of the radius of curvature along the longitudinal direction with the mold. The metal plate 10 used for press molding is a steel plate having a thickness t = 1.4 mm and a tensile strength of 590 MPa to 1470 MPa, and the first step is formed by foam molding. .

  The press molding analysis was performed using the mold model of the first process designed as described above, and the spring back analysis after the release of the press-molded product molded to the bottom dead center was performed. Thereafter, a molding analysis was performed in which the molded product after the spring back was subjected to restric molding in the second step, and a spring back analysis was performed after the release of the press molded product molded to the bottom dead center.

Table 1 summarizes the press conditions and evaluation results.
Here, an evaluation was made based on a value obtained by averaging the amount of deviation from the product at both ends in the longitudinal direction of the component. The camber back that is the spring back in the longitudinal direction of the component (the amount of deviation from the product) is in the range of ± 1.0 mm with respect to the product, and the material strength sensitivity is in the range of 1.0 mm between 590-1470 MPa materials. Explain as a criterion for passing.

No. in Table 1 1-4 is a case where the spring back analysis is performed without performing the first step, that is, by performing press forming without changing the curvature radius of the first step. This No. In 1-4, the maximum deviation from the product is 3.2 mm with 1470 MPa material. When the difference between the 590 MPa material and the 1470 MPa material is compared, it can be seen that a difference of 2.3 mm occurs.
No. 1 in Table 1 5 to 8 are analysis results when the material strength condition is 1470 MPa material and the first mold is set so that (R1 ′ / R1o) and (R2 ′ / R2o) are set to 1.1. It is. Here, (R1 ′ / R1o) and (R2 ′ / R2o) were set to 1.1 because the camber back (the amount of deviation from the product) after the first and second steps was set to 0. This is to make it 0 mm.

  No. In the case of 5-8, the camber back was a 590 MPa material having the lowest strength, and the product shape was almost 0.0 mm, but 1.5 mm was generated with the 1470 MPa material, which is larger than the standard. Further, the difference between the 590 MPa material and the 1470 MPa material was 1.5 mm, and although the material strength sensitivity was reduced as compared with the conventional method, the value was larger than the standard.

In contrast, No. 1 in Table 1. 9 to 12 are analysis results in which the material strength condition is 1470 MPa, and (R1 ′ / R1o) and (R2 ′ / R2o) are set to 0.9. The camber back was a 590 MPa material having the lowest material strength and was displaced to -0.8 mm toward the spring go side, but was not generated as 0.0 mm with a 1470 MPa material, and was within the standard for all strengths. Further, the difference between the 590 MPa material and the 1470 MPa material was 0.8 mm, and the material strength sensitivity was reduced as compared with the conventional method and the comparative example, and the dimensional accuracy was within the standard. This is because in the materials other than the 1470 MPa material having the highest material strength, the stress is reversed at the bottom dead center in the second step, and the stress difference is reduced by the Bauschinger effect.
As described above, it can be seen that by designing the mold based on the present invention, the effect of suppressing the spring back of the entire product processed with the same mold is improved.

DESCRIPTION OF SYMBOLS 1 Top plate part 2 Flange part 3 Side wall part 10 Metal plate 20 Intermediate part

Claims (6)

A top shape in which the top plate portion and the flange portion are continuous in the width direction through the side wall portion, and the top plate portion and the flange portion are curved convexly or concavely toward the top plate portion side along the longitudinal direction. When manufacturing a metal plate by press molding into a product shape having a cross section,
The top plate portion and the flange portion are each press-molded with a first die into a part shape having a hat-shaped cross section having a second curvature radius smaller than the curvature radius of the product shape, along the longitudinal direction. A first step of manufacturing an intermediate part, and a second step of press-molding the intermediate part into the product shape with a second mold,
In a plurality of metal plates assumed to be press-molded using the same mold, a metal plate assumed to have the highest material strength is used as a representative metal plate, and the material conditions of the representative metal plate are as described above. After performing the press molding in the first step and the second step and removing it from the second mold, a simulation analysis is performed so that the part shape after the occurrence of springback approaches the product shape. A method for producing a press-molded product, characterized in that the configuration of one mold is set.   The configuration of the first mold to be set is such that at least the curvature radius in the longitudinal direction of the part on the surface of the top plate portion and the flange portion where the curved portion is pressed is equal to or less than the second curvature radius. The method for producing a press-formed product according to claim 1. When the radius of curvature along the longitudinal direction of the top plate portion in the product shape is defined as R1o, the curvature radius R1 ′ along the longitudinal direction of the top plate portion after the spring back in the intermediate part is expressed by the following formula (1). The method for manufacturing a press-formed product according to claim 1 or 2, wherein the value of the second radius of curvature at the top plate portion is set so as to satisfy a value.
0.70 ≦ (R1 ′ / R1o) <1.00 (1) When the radius of curvature along the longitudinal direction of the flange portion in the product shape is defined as R2o, the radius of curvature R2 ′ along the longitudinal direction of the flange portion after springback in the intermediate part satisfies the following formula (2) The method of manufacturing a press-formed product according to any one of claims 1 to 3, wherein a value of the second radius of curvature at the flange portion is set so that
0.70 ≦ (R2 ′ / R2o) <1.00 (2)   5. The restructuring process in which draw molding or foam molding is applied in the first process, and the product is molded into a product shape in the second process. 5. Manufacturing method for pressed products. The method for producing a press-formed product according to any one of claims 1 to 5, wherein the metal plate has a material strength of 590 MPa or more.

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