JP2006205244A - Warm-formed article and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a warm-formed article which has excellent formability and can exhibit excellent bake hardenability as well, and to provide its production method. <P>SOLUTION: The warm-formed article is obtained by subjecting a sheet stock 1 composed of an Al-Mg-Si based aluminum alloy sheet comprising, by mass, 0.5 to 2.0% Si and 0.2 to 1.5% Mg, and subjected to T4 treatment to warm forming. The production method uses the same. In the production method, a holding stage and a forming stage are performed. In the holding stage, the edge parts of the sheet stock 1 are held by dies 22 and wrinkle pressers 23 in a forming apparatus 2. In the forming stage, a punch 21 in the forming apparatus 2 relatively advances with respect to the dies 22, so as to form the sheet stock 1. In the holding stage and the forming stage, the temperatures of the flange parts 15 held by the dies 22 and the wrinkle pressers 23 and the punch 21, and time are controlled. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a warm-formed product such as an automobile outer plate (body sheet) formed by warm-forming an Al—Mg—Si-based aluminum alloy plate and a method for manufacturing the same.

In recent years, as the demand for energy saving of automobiles becomes more and more severe, further weight reduction of automobiles has been promoted. As one of the countermeasures, a lighter aluminum alloy sheet molded product has been used for an automobile outer plate (body sheet), which has conventionally used a molded product such as a mild steel plate.
Examples of the aluminum alloy plate include an Al—Mg type and an Al—Mg—Si type aluminum alloy plate. In particular, the Al—Mg—Si-based aluminum alloy plate exhibits so-called bake hardness and can be improved in strength by heating in the paint baking process and the like, and thus is particularly suitable for applications such as automobile outer plates. It is thought that there is.

  However, in general, an aluminum alloy plate has a problem that ductility and r value are lower than that of a mild steel plate and formability is poor. For this reason, when an aluminum alloy plate is formed, there are cases where it cannot be formed into a desired shape due to design restrictions. Such a design restriction has been a hindrance to aluminization of automobile outer plates and the like.

Warm forming is known as a forming method for improving the formability of an aluminum alloy plate. Conventionally, in warm forming, an Al—Mg alloy plate having relatively good warm formability has been used as an aluminum alloy material (see Patent Document 1).
Further, in order to improve the formability by improving the limit drawing ratio of the A5182P-O type aluminum alloy, in the warm deep drawing forming process, the flange portion of the aluminum alloy material is set to a temperature lower than 50 ° C. below the melting temperature of the material. A method of forming by heating locally and cooling the punch has been developed (see Patent Document 2).

However, the conventional warm forming method of an aluminum alloy plate uses an Al—Mg alloy plate or an A5182P—O aluminum alloy plate as described above, and the Al—Mg—Si aluminum alloy plate is formed. Little technology has been developed to improve performance.
In the warm forming of Al-Mg-Si based aluminum alloy sheet, not only the formability is improved, but also the warm forming process without impairing the excellent bake hardness inherent in the Al-Mg-Si based aluminum alloy sheet. It is desirable to produce a product.

  However, when the Al-Mg-Si aluminum alloy plate is formed by the same method as the warm forming of the conventional Al-Mg alloy plate or A5182P-O aluminum alloy plate, the formability and the bake hardness are low. In some cases, it was damaged. For example, when the method described in Patent Document 2 is applied to the warm forming of an Al—Mg—Si based aluminum alloy plate, the material is age-hardened or softened during the warm forming, so that the warm formability and the baking. There was a possibility that the hard property would be impaired. In addition, there is a case where the shrinkage of the flange portion is not sufficiently reduced and the moldability is not sufficiently improved.

JP 7-310137 A JP-A-4-351229

  The present invention has been made in view of such conventional problems, and intends to provide a warm-formed product of an aluminum alloy plate that is excellent in formability and can exhibit excellent bake hardness and a method for producing the same. Is.

The first invention is a method for producing a warm-formed product by warm-forming a material plate made of an Al-Mg-Si-based aluminum alloy plate using a forming apparatus having a punch, a die, and a wrinkle retainer. In
As the material plate, an Al-Mg-Si-based aluminum alloy plate containing 0.5 to 2.0 mass% of Si, 0.2 to 1.5 mass% of Mg, and treated with T4 is used.
A holding step of clamping the end of the material plate with the die of the molding apparatus and the wrinkle presser;
A molding step of molding the material plate by advancing the punch of the molding device relative to the die,
In the holding step, the flange portion sandwiched by the die and the wrinkle presser of the material plate is heated to a temperature T (150 ≦ T ≦ 300) ° C. for t ₁ (t ₁ = −0.1 × T + 31) minutes or less. Hold heated,
In the molding step, molding is performed within a molding time t ₂ (t ₂ = −0.06 × T + 20) minutes in a state where the temperature of the punch is maintained at a temperature 30 ° C. or more lower than the temperature T ° C. of the flange portion. In the method of manufacturing a warm-formed product,

In the manufacturing method according to the first aspect of the invention, as described above, an Al—Mg—Si based aluminum alloy plate that contains the specific amount of Mg and Si and is T4 treated is used as the material plate. Further, in the holding step, the heating temperature and heating holding time of the flange portion of the blank plate are controlled to a specific range, and in the forming step, the punch temperature and the forming time are controlled to a specific range.
Therefore, in the forming step, the balance between age hardening, work hardening, and softening of the material plate is maintained in a state suitable for warm forming. Therefore, the shrinkage flange resistance can be reduced without substantially reducing the breaking resistance at the shoulder portion of the punch (hereinafter referred to as “punch shoulder portion” as appropriate) of the molding apparatus. As a result, the limit drawing ratio can be improved and the formability of the material plate can be improved.

  Further, in the holding step and the molding step, excessive progress of age hardening can be suppressed. Therefore, the warm-molded product obtained after the molding step can exhibit so-called bake hardness. Therefore, by heating the warm molded product, it is possible to improve the yield strength of the warm molded product and increase its strength.

  Thus, according to the said 1st invention, while being excellent in a moldability, the manufacturing method of the warm-formed product of the aluminum alloy plate which can exhibit the outstanding bake hard property can be provided.

  The second invention is a warm-molded product obtained by the manufacturing method of the first invention, wherein after the molding step, the warm-molded product is heat-treated at a temperature of 150 to 200 ° C. for 20 minutes. In the warm-molded product, the yield strength after heat treatment is 160 MPa or more, and the increase in the yield strength by the heat treatment is 10 MPa or more (Claim 3).

The warm-molded product of the second invention is a warm-molded product obtained by the manufacturing method of the first invention.
Therefore, as described above, the moldability is excellent, and excellent bake hardness can be exhibited.

The warm-formed product has a yield strength after the heat treatment of 160 MPa or more, and an increase in the yield strength after the heat treatment is 10 MPa or more. That is, the warm-formed product can be easily improved in strength by heating, while exhibiting a certain degree of ductility before heating. Therefore, for example, before the warm-formed product is heated to obtain a high-strength final product, the warm-formed product can be subjected to secondary processing such as bending.
Generally, at the time of secondary processing, cracks may occur if the strength of the molded product is too high, but the warm molded product has bake-hardness as described above and is compared before heat treatment. Can be processed easily.

Further, in the manufacture of an automobile outer plate or the like, generally, secondary processing such as bending is further performed after molding, and then heating by paint baking is performed.
The warm-molded product has formability at the time of secondary processing, increases strength at the time of paint baking, and can exhibit excellent proof stress of 160 MPa or more. Therefore, the warm-molded product is particularly suitable for applications such as automobile outer plates.

Next, an embodiment of the present invention will be described.
In the method for manufacturing a warm-formed product, the holding step and the forming step are performed to warm-form a material plate made of an Al—Mg—Si-based aluminum alloy plate (6000-based alloy plate).

The Al—Mg—Si based aluminum alloy plate as the material plate is an aluminum alloy plate containing Si and Mg as main additive elements. The Al—Mg—Si-based aluminum alloy plate contains 0.5 to 2.0 mass% of Si and 0.2 to 1.5 mass% of Mg in addition to Al.
If the Si content is less than 0.5 mass% or the Mg content is less than 0.2 mass%, sufficient moldability may not be obtained. Therefore, there is a possibility that sufficient baking hardness cannot be exhibited. As the heat treatment for showing the bake hard property, for example, a heat treatment can be performed by holding for 20 minutes within a temperature range of 150 to 200 ° C. In addition, if the Si content exceeds 2.0 mass% or the Mg content exceeds 1.5 mass%, sufficient moldability may not be obtained, and during the molding in the molding step, In addition, the material plate is age-hardened, and the strength may be too high. As a result, there is a possibility that the bake hardness cannot be obtained.

Further, the Al—Mg—Si-based aluminum alloy plate as the material plate is a range that does not inhibit the effects of the present invention, for example, elements such as Cu, Zn, Mn, Cr, Zr, Fe, and Ti, and inevitable impurities. Can be contained. Specifically, Cu, Zn, and Mn can each be 2.0 mass% or less, Cr, Zr, Fe, and Ti can each be 0.5 mass% or less, and unavoidable impurity elements can be 0.2 mass% or less.
When the Al—Mg—Si aluminum alloy plate as the material plate contains Cu and / or Zn, the bake hardness can be further improved. Moreover, when 1 or more types chosen from Mn, Cr, Zr, Fe, and Ti are contained, refinement | miniaturization of the crystal grain diameter of material can be achieved.
In the Al—Mg—Si based aluminum alloy plate as the material plate, the remainder excluding additive elements such as Mg, Si, Cu, Zn, Mn, Cr, Zr, Fe, Ti and inevitable impurities is Al.

  Further, as the material plate, an Al—Mg—Si based aluminum alloy plate that has been T4 treated, that is, naturally aged after solution treatment is used. When the tempering of the Al—Mg—Si-based aluminum alloy sheet material is, for example, O or T6 other than T4, sufficient warm formability and bake hardness may not be obtained.

Next, in the holding step, the end portion of the material plate is sandwiched between the die of the molding apparatus and the wrinkle presser. At this time, the flange portion sandwiched by the die and the wrinkle retainer of the material plate is heated and held at a temperature T (150 ≦ T ≦ 300) ° C. for t ₁ (t ₁ = −0.1 × T + 31) minutes or less. .

When the temperature T of the flange portion is less than 150 ° C., the shrinkage flange resistance in the flange portion is insufficiently reduced during the molding process, and the moldability may not be sufficiently improved. On the other hand, when the temperature exceeds 300 ° C., the Al—Mg—Si-based aluminum alloy plate as the material plate is age-hardened or softened during the forming process, which may impair the warm formability and bake hardness. There is.
Further, when the heating retention time exceeds ₁ minute t, there is a possibility that Al-Mg-Si based aluminum alloy plate as the blank is age hardened, warm formability and bake hardenability is impaired .
T ₁ may be 0 minutes. That is, t ₁ is in the range of 0 ≦ t ₁ ≦ −0.1 × T + 31, and immediately after the temperature of the flange portion is set to T ° C. in the holding step, it is not held at that temperature (T ° C.). Molding in the molding process can be performed.
The heating and holding time t ₁ is a time for heating and holding the flange portion at a temperature T ° C. in the holding step, and does not include the time in the molding step described later. Therefore, in the molding step after the holding step, the flange portion can be heated and held at a temperature T ° C. regardless of the heating and holding time t ₁ .

Moreover, in the said formation process, the said punch of the said shaping | molding apparatus is advanced relatively with respect to the said die | dye, and the said raw material board is shape | molded. At this time, molding is performed within a molding time t ₂ (t ₂ = −0.06 × T + 20) minutes in a state where the temperature of the punch is maintained at a temperature lower by 30 ° C. or more than the temperature T ° C. of the flange portion.

When the temperature difference between the punch and the flange portion (temperature T ° C) is less than 30 ° C, the fracture resistance of the punch shoulder portion does not increase in the molding step, and the effect of improving the limit drawing ratio may not be obtained. is there.
When the molding time t ₂ exceeds (−0.06 × T + 20) minutes, the flange portion of the material plate is age-hardened during the warm molding, and the warm-molded product is sufficiently baked and hardened. May not be able to demonstrate. In this case, the shrinkage flange resistance increases, and there is a possibility that a sufficient improvement effect of the limit drawing ratio cannot be obtained. In addition, since the flange portion that has been work-hardened during molding may not be sufficiently recovered and the shrinkage of the flange resistance may be insufficiently reduced, the molding time t ₂ is preferably 0.02 minutes or more. More preferably, the molding time t ₂ is 0.1 minutes or longer.

In the molding step, it is preferable to perform the molding process in a state where the temperature of the punch is heated at room temperature or a temperature exceeding room temperature. That is, it is preferable to perform the molding process without heating the punch at room temperature or in a state of heating to a temperature exceeding room temperature.
In this case, the temperature difference between the punch and the flange portion can be easily controlled. Moreover, when the temperature of the punch is cooled below room temperature, dew condensation occurs, and moisture may be mixed into the lubricating oil used at the time of molding, causing poor lubrication. As described above, by keeping the punch at room temperature or heating it to a temperature exceeding the room temperature, it is possible to prevent the formation of condensation and suppress poor lubrication.

Particularly preferably, the temperature of the punch is room temperature.
That is, in the present invention, as described above, the temperature of the punch may be lower by 30 ° C. or more than the temperature T ° C. of the flange portion. However, lowering the punch temperature can reduce the heat energy for heating the punch, Manufacturing costs can be reduced. On the other hand, if the punch temperature is lower than room temperature as described above, there is a risk of poor lubrication due to the occurrence of condensation.
Therefore, by setting the temperature of the punch to room temperature without heating or cooling the punch, poor lubrication can be suppressed and the manufacturing cost can be reduced.
Note that the room temperature refers to a state in which temperature adjustment is not performed by so-called heating or cooling regardless of the season or place.

  Moreover, in the said formation process, the said raw material board can be shape | molded, for example by deep drawing shaping | molding, an extending | stretching process, etc., and the said warm forming processed product can be produced.

Further, the warm molded product of the second invention has a yield strength of 160 MPa or more after performing a heat treatment of heating the warm molded product at a temperature of 150 to 200 ° C. for 20 minutes, and is based on the heat treatment. The increase in proof stress is 10 MPa or more.
When the proof stress after heat treatment is less than 160 MPa, the strength of the warm-molded product is insufficient, and may not be suitable for applications such as an automobile outer plate. On the other hand, when the amount of increase in yield strength by the heat treatment is less than 10 MPa, sufficient bake-hardness cannot be exhibited, and in this case as well, there is a possibility that it is not suitable for applications such as automobile outer plates.

Example 1
Next, an embodiment of the present invention will be described with reference to FIGS.
In this example, as shown in FIG. 1, a material plate 1 made of an Al—Mg—Si based aluminum alloy plate is warm-formed using a forming device 2 having a punch 21, a die 22, and a wrinkle presser 23. To produce warm-formed products. As the material plate 1, an Al—Mg—Si based alloy plate containing 0.5 to 2.0 mass% of Si and 0.2 to 1.5 mass% of Mg and subjected to T4 treatment is employed.

In this example, a warm forming product is manufactured by performing a holding process and a forming process.
In the holding step, the end portion of the material plate 1 is sandwiched between the die 22 and the wrinkle presser 23 of the molding apparatus 2. At this time, the flange portion 15 held by the die 22 and the wrinkle retainer 23 of the material plate 1 is heated and held at a temperature T (150 ≦ T ≦ 300) ° C. for t ₁ (t ₁ = −0.1 × T + 31) minutes or less. To do.

Further, in the forming step, the blank 21 is formed by advancing the punch 21 of the forming apparatus 2 relative to the die 22. At this time, molding is performed within a molding time t ₂ (t ₂ = −0.06 × T + 20) minutes in a state where the temperature of the punch 21 is maintained at a temperature lower by 30 ° C. than the temperature T ° C. of the flange portion 15.

Hereinafter, the manufacturing method of the warm formed product of this example will be described in detail.
First, as shown in FIG. 1, a forming apparatus 2 including a punch 21, a die 22, and a wrinkle presser 23 was prepared. In the punch 21, the punch diameter is φ50 mm, and the shoulder radius of the punch shoulder 215 is R5 mm. In the die 22, the shoulder radius of the die shoulder 225 is R5 mm. Further, the punch 21, the die 22, and the wrinkle presser 23 each have a built-in heater 3, and the temperature of the punch 21, die 22, and wrinkle presser 23 can be controlled.

Next, an Al—Mg—Si-based aluminum alloy plate (6016 alloy plate) having a disk shape and a plate thickness of 1 mm was prepared as the material plate 1. The material plate 1 contains 0.48 mass% Mg and 1.0 mass% Si. Next, molybdenum disulfide as a lubricant was applied to both surfaces of the material plate 1 by spraying, and the material plate 1 was held between the die 22 and the wrinkle retainer 23 of the molding apparatus 2.

  Next, the flange 3 of the material plate 1 sandwiched between the die 22 and the wrinkle retainer 23 was heated to a temperature of 150 ° C. by the heater 3 incorporated in the die 22 and the wrinkle retainer 23 (heating holding time 0 minutes). Next, with the heater 3 incorporated in the punch 21, the punch 21 is heated relative to the die 22 in a state where the temperature of the punch 21 is 30 ° C. lower than the temperature of the flange portion 15, that is, 120 ° C. The raw material plate 1 was moved forward and deep-drawn to form a cylindrical warm-formed product (sample E1) having a bottom. Molding was performed in 0.2 minutes, and the limit drawing ratio at this time was measured.

The limit drawing ratio (L.D.R) is 3 without breaking, when 5 blanks with the same diameter are formed for each blank diameter while changing the blank diameter. Assuming that the maximum diameter of the material plate when it has been formed is the maximum blank diameter, it can be calculated from the following equation (1). The results are shown in Table 1.
L. D. R = maximum blank diameter / punch diameter (1)

  Further, in this example, the sample E1 was subjected to warm forming in the same manner as the sample E1 except that the heating temperature of the flange portion, the heating and holding time, the temperature of the punch, and the molding time were changed. Warm-formed products (samples E2 to E5) were produced, and the limit drawing ratio was measured. The results are shown in Table 1.

  Further, in this example, for comparison with the samples E1 to E5, the sample E1 is different from the sample E1 in the type (tempering) of the material plate, the heating temperature of the flange portion, the heating holding time, the punching temperature, and the molding time. In other respects, warm forming was performed in the same manner as the sample E1, and a plurality of warm formed products (samples C1 to C8) were produced, and the limit drawing ratio was measured. The results are shown in Table 1.

Furthermore, in this example, the bake hardness of the warm-formed products of Sample E1 to Sample E5 and Sample C1 to Sample C8 was evaluated by a tensile test.
Specifically, first, heat treatment was performed by heating Sample E1 to Sample E5 and Sample C1 to Sample C8 at a temperature of 170 ° C. for 20 minutes. This heat treatment was performed within 30 minutes to 1 hour after molding of each sample.
Subsequently, a test piece for a tensile test was cut out from the bottom of each sample (sample E1 to sample E5 and sample C1 to sample C8) of a cylindrical warm-formed product having a bottom (Fig. 2). And FIG. 3). As shown in the figure, the test piece has a parallel portion having a width of 8 mm and a length of 8 mm.

Next, using this test piece, the proof stress of the test piece of each sample was measured according to the “metal material tensile test method” defined in JIS Z 2241 (1998). The results are shown in Table 1.
Moreover, the test piece for the tensile test similar to the above was produced from each sample of the warm-molded product (Sample E1-Sample E5 and Sample C1-Sample C8) before performing the said heat processing, and the yield strength was measured. The amount of increase in yield strength due to heat treatment was calculated by determining the difference in yield strength before and after heat treatment, that is, by subtracting the value of yield strength before heat treatment from the value of yield strength after heat treatment, and the results are shown in Table 1.

As is known from Table 1, the warm-formed products of Samples E1 to E6 exhibit a high limit drawing ratio of 2.2 or higher, a high yield strength after baking hard of 167 MPa or higher, and a high yield strength of 12 MPa or higher. Amount indicated. Therefore, it can be seen that the warm molded products of Samples E1 to E6 are excellent in moldability and bake hardness.
On the other hand, Sample C1 to Sample C8 had a lower limit drawing ratio than Sample E1 to Sample E6 and had insufficient moldability. Sample C2 had a very low yield strength after baking, and Samples C2, C3, C5, C6, and C8 had a small increase in yield before and after baking, and these were insufficient in bake hardness.

  As described above, according to this example, as in samples E1 to E5, the moldability and bake hardness are improved by controlling the tempering of the material plate, the heating condition of the flange, the punch temperature, and the molding time. I understand that I can do it.

(Example 2)
This example is an example in which a warm-formed product was produced in the same manner as in Example 1 using material plates made of Al—Mg—Si-based aluminum alloy plates having different compositions, and the formability and bake hardness were evaluated. .
First, as a material plate, 1.0 mass% Si, 0.48 mass% Mg, 0.11 mass% Fe, 0.01 mass% Cu, 0.11 mass% Mn, 0.03 mass% Ti, An Al—Mg—Si aluminum alloy plate having a disk shape and a plate thickness of 1 mm treated with T4 was prepared.
A molding apparatus similar to that in Example 1 was prepared.

  Next, in the same manner as in Example 1, the material plate was sandwiched between a die and a wrinkle retainer of a molding apparatus. Next, the flange portion sandwiched between the die and the wrinkle presser was heated to a temperature of 300 ° C. by a heater built in the die and the wrinkle presser of the molding apparatus, and held at that temperature for 1 minute. Next, with the heater 3 incorporated in the punch, the punch is moved forward relative to the die in a state where the temperature of the punch is 30 ° C. lower than the temperature of the flange, that is, 270 ° C. The cylindrical warm-formed product (sample E6) having the bottom was prepared in the same manner as in Example 1. Molding was performed in 2 minutes, and the limit drawing ratio at this time was measured in the same manner as in Example 1. The results are shown in Table 2 below.

In this example, a material plate made of an Al—Mg—Si-based aluminum alloy plate having a different composition from that of the sample E6 is used, and the other six types of warm forming processes are performed in the same manner as the sample E6. Articles (Samples E7 to E8 and Samples C9 to C12) were produced, and the limit drawing ratio was measured. The specific composition and limit drawing ratio of each sample are shown in Table 2 below.
Moreover, evaluation of the bake hard property of each sample (sample E6 to sample E8 and sample C9 to sample C12) was performed by the same tensile test as in Example 1. The results are shown in Table 2.

  As is known from Table 2, sample E6 produced using a material plate made of an Al—Mg—Si based aluminum alloy plate containing 0.5 to 2.0 mass% of Si and 0.2 to 1.5 mass% of Mg. -Sample E8 exhibited a high limit drawing ratio of 2.2, a high yield strength after baking hard of 190 MPa or more, and a high yield increase of 12 MPa or more. Therefore, it can be seen that the warm molded products of Sample E6 to Sample E8 are excellent in moldability and also in bake hardness.

  In contrast, a material plate made of an Al—Mg—Si based aluminum alloy plate having a composition in which the contents of Si and Mg deviate from the ranges of 0.5 to 2.0 mass% and 0.2 to 1.5 mass%, respectively. Samples C1 to C8 produced in this manner had a lower limit drawing ratio than Samples E6 to E8, and the moldability was insufficient. In addition, Sample C9 and Sample C11 had low yield strength after baking, Samples C9 to C12 had a small increase in yield before and after baking, and these were insufficient in baking properties.

  Thus, according to this example, by adjusting the content of Si and Mg in the Al—Mg—Si based aluminum alloy plate as the material plate as in the samples E6 to E8, the formability and the bake hardness are adjusted. It can be seen that the performance can be improved.

Explanatory drawing which shows a mode that an Al-Mg-Si type | system | group aluminum alloy board is deep-drawn using the shaping | molding apparatus which comprises a punch, die | dye, and a wrinkle presser concerning Example 1. FIG. The top view which shows the shape of the test piece for a tensile test concerning Example 1. FIG. The side view which shows the shape of the test piece for a tension test concerning Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Material board 15 Flange part 2 Forming apparatus 21 Punch 22 Dies 23 Wrinkle holding

Claims (3)

In a method for producing a warm-formed product by warm-forming a material plate made of an Al-Mg-Si-based aluminum alloy plate, using a forming device having a punch, a die, and a wrinkle presser,
As the material plate, an Al-Mg-Si-based aluminum alloy plate containing 0.5 to 2.0 mass% of Si, 0.2 to 1.5 mass% of Mg, and treated with T4 is used.
A holding step of clamping the end of the material plate with the die of the molding apparatus and the wrinkle presser;
A molding step of molding the material plate by advancing the punch of the molding device relative to the die,
In the holding step, the flange portion sandwiched by the die and the wrinkle presser of the material plate is heated to a temperature T (150 ≦ T ≦ 300) ° C. for t ₁ (t ₁ = −0.1 × T + 31) minutes or less. Hold heated,
In the molding step, molding is performed within a molding time t ₂ (t ₂ = −0.06 × T + 20) minutes in a state where the temperature of the punch is maintained at a temperature 30 ° C. or more lower than the temperature T ° C. of the flange portion. A method for producing a warm-formed product, characterized in that   2. The method of manufacturing a warm-formed product according to claim 1, wherein in the forming step, the forming is performed in a state where the temperature of the punch is heated at a room temperature or a temperature exceeding the room temperature.   A warm-formed product obtained by the production method according to claim 1 or 2, wherein after the molding step, the warm-formed product is subjected to a heat treatment for heating at a temperature of 150 to 200 ° C for 20 minutes. Is a warm-formed product, characterized in that the increase in yield strength by the heat treatment is 10 MPa or more.

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