JP2011200932A - Method for manufacturing press-formed product of light metal alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a press-formed product of a light metal alloy which can eliminate any defective shape such as an excessive radius of curvature of a folded R part, and eliminating any crack in the folded R part during the manufacture.SOLUTION: The method for manufacturing the press-formed product of the light metal alloy includes a drawing step and a second finishing step. The depth of a recess 3 of a semi-formed product 1b when completing the drawing step is larger than the depth of the press-formed product 1 after completing the second finishing step, and the radius of curvature of the folded R part 2 of the semi-formed product 1b when completing the drawing step is larger than the radius of curvature of the folded R part 2 of the press-formed product 1 after completing the second finishing step.

Description

  The present invention relates to a press-formed product made of a light alloy material including an aluminum alloy used for an automobile panel, an automobile part, a panel for a transport machine such as a railway vehicle, or an electric machine part. The present invention relates to a method for manufacturing a light alloy material press-molded product in which press molding is divided into a drawing process and a post-finishing process.

  In recent years, automobile weight tends to increase due to the background of improving safety and enhancing comfort equipment. In addition, in the body field of the entire transportation equipment including automobiles, improvement of fuel efficiency by pursuing light weight is pursued for global environmental problems caused by exhaust gas and the like. For this reason, press-formed products and extruded molds made of light alloy rolled plates, such as lighter aluminum alloy plates, are often used instead of steel plates that have been used in the body of transportation equipment such as automobiles. It has become to. In addition, press-molded products made of light alloy materials such as aluminum alloy plates are increasingly used for electromechanical parts and the like.

  Conventionally, when manufacturing a press-formed product with a steel plate, the corner portion has been formed into an R shape, but the method for forming the R shape of the corner portion of the steel plate is followed as it is, including aluminum alloy plates. When a press-molded product made of a light alloy material is manufactured, the light alloy plate such as an aluminum alloy plate has a lower forming limit than a steel plate, and therefore cracks occur in the corner portion. Therefore, when adopting a light alloy plate such as an aluminum alloy plate, the R shape of the corner portion has conventionally been an R shape having a larger radius of curvature than the steel plate. However, press-formed products made of light alloy materials such as aluminum alloy plates are often used in combination with parts used for press-formed products made of steel plates. Since there is a difference in the radius of curvature of the corners of the parts used for the molded product and the press-formed product made of steel plate, there is a problem that they interfere with each other when used together.

  For this reason, many proposals have been made with the aim of preventing cracks in the corners when manufacturing press-formed products made of light alloy materials such as aluminum alloy plates.

  The proposal described in Patent Document 1 is the same as a soft part having a low yield strength, in which the central part of the aluminum alloy plate blank is a hard part having a high yield strength, while the peripheral part is partially heated in advance before press molding. Aluminum alloy plate blank mixed with hard and soft parts to improve press formability and to prevent cracks at corners when manufacturing press-formed products This is a proposal for a board blank.

  The proposal described in Patent Document 2 also tried to improve the deep drawability by giving the aluminum alloy blank an optimal strength distribution according to the object to be molded and to eliminate the occurrence of cracks at the corners. It is a proposal. Specifically, in the molding part with the highest drawing height among the press-molded products, the blank strength of the shrinking flange deformation part that undergoes shrinkage flange deformation at the time of press molding is greater than the punch bottom contact part that the punch bottom contacts at the time of press molding. In advance, and a blank for press molding in which the blank strength continuously transitions in a range corresponding to a drawing height that becomes a wall portion between the contracted flange deformation portion and the punch bottom contact portion, and a proposal relating to the molding method It is.

  The proposal described in Patent Document 3 is that the Al—Mg—Si based aluminum alloy plate that has undergone solution treatment and quenching treatment is subjected to heat treatment at 180 to 250 ° C. for 3 to 20 hours, and then cut into a predetermined shape. The aluminum alloy blank is made into an aluminum alloy blank, and the aluminum alloy blank for press forming is made by performing instantaneous heating at a temperature of 480 to 550 ° C. for 0.5 to 10 seconds only on the planned processing portion of the blank. This is a proposal to prevent the occurrence of cracks at the corners during press molding by manufacturing the aluminum alloy blank in this way.

  However, all of the techniques described in Patent Documents 1 to 3 are proposals to give a strength distribution to the aluminum alloy blank in advance, and certainly suppress the occurrence of cracks at the corners. Although it is possible, it is not a proposal to provide a versatile aluminum alloy blank material corresponding to any molding shape, and its application range is limited.

JP 2008-207212 A JP 2008-246555 A JP 2009-242907 A

  The present invention has been made in view of the above-described conventional situation. When a press-molded product made of a light alloy material such as an aluminum alloy is manufactured from a workpiece, the curvature radius of the bent R portion is excessive. It is an object of the present invention to provide a method for manufacturing a press-formed product made of a light alloy material, which can eliminate the occurrence of a shape defect such as the above, and can eliminate cracks generated in the bent R portion during manufacturing. It is.

  The invention according to claim 1 is a light alloy material press-molded product for producing a press-molded product having a recess surrounded by a side wall portion and a bottom wall portion through press molding from a workpiece made of a light alloy material. In the manufacturing method, the press molding is composed of a drawing process and a post-finishing process, and the depth of the recess of the semi-processed product at the end of the drawing process is the depth of the press-molded product after the post-finishing process. The radius of curvature of the bent R portion of the semi-processed product at the end of the drawing process is larger than the radius of curvature of the bent R portion of the press molded product after the finishing process. It is the manufacturing method of the press molding product made from the light alloy material characterized.

  The invention according to claim 2 is characterized in that, in the post-finishing step, at least one of the pair of pressure bodies that sandwich the workpiece including the bent R portion is a heating body. 2. The light alloy material according to claim 1, wherein the post-finishing step is performed in a state where the surface temperature including the bent portion of the workpiece is heated to 200 to 300 ° C. with the heating body. It is a manufacturing method of a press-formed product.

  According to a third aspect of the present invention, the bent R portion of the press-formed product is a punch shoulder, the radius of curvature of the punch shoulder of the semi-processed product at the end of the draw forming process is Rp, and the press after the end of the post-finishing process 0.02 <(L / Rp) × (rp / Rp) <0, where rp is the radius of curvature of the punch shoulder of the molded product and L is the difference in the depth of the recess between the half-processed product and the press-formed product. The method of manufacturing a press-formed product made of a light alloy material according to claim 1, wherein a relationship of 08 is established.

  According to a fourth aspect of the present invention, the radius of curvature of the die shoulder of the half-finished product at the end of the drawing process is Rd, the radius of curvature of the die shoulder of the press-molded product after the post-finishing step is rd, The relationship of 0.02 <(L / Rd) × (rd / Rd) <0.08 is established, where L is the difference in the depth of the recess of the press-formed product. 2. A method for producing a press-formed product made of a light alloy material according to 2.

According to a fifth aspect of the present invention, the bent R portion of the press-formed product is a punch shoulder and a die shoulder, the radius of curvature of the punch shoulder of the semi-processed product at the end of the draw forming process is Rp, and the finishing process is finished The radius of curvature of the punch shoulder of the subsequent press-formed product is rp, the radius of curvature of the die shoulder of the semi-finished product at the end of the drawing process is Rd, and the radius of curvature of the die shoulder of the press-formed product after the end of the post-finishing process is rd, where L is the difference in the depth of the recess between the half-processed product and the press-formed product, 0.005 <{L ² / (Rp × Rd)} × (rp / Rp) × (rd / Rd) < The light alloy material press-molded product manufacturing method according to claim 1 or 2, wherein a relationship of 0.02 is established.

  According to the light alloy material press-molded product manufacturing method of the present invention, a light alloy material work material such as an aluminum alloy is subjected to press molding and has a recess surrounded by a side wall portion and a bottom wall portion. When manufacturing press-molded products with a hat-shaped cross section, the occurrence of shape defects such as excessive curvature radius of the bent R part is divided into the drawing process and the post-finishing process, and the conditions of these molding processes are By prescribing, it can be eliminated, and the occurrence of cracks in the bent R portion can also be suppressed.

  In addition, the surface temperature of the work piece including the bent portion R in the post-finishing process, the plate thickness of the work piece, the half-finished product at the end of the drawing process and the bending of the press-formed product after the end of the post-finishing process By specifying and controlling the radius of curvature of the R portion in detail, it is possible to more reliably suppress the occurrence of shape defects such as excessive curvature radius of the bent R portion and the occurrence of cracks in the bent R portion. can do.

It is a longitudinal cross-sectional view which shows the process which manufactures a press-molded product with the manufacturing method of the light alloy material press-molded product of this invention, (a) shows a drawing process, (b) shows a post-finishing process, respectively. . It is an example of the press molded product manufactured with the manufacturing method of the light alloy material press molded product of this invention, Comprising: The detailed dimension of the press molded product manufactured in the Example is shown, (a) is a longitudinal cross-sectional view, (b) Is a plan view.

  The present inventors process press-formed products made of light alloy materials including aluminum alloys used for automobile panels, automobile parts, other panels for transportation equipment such as railway vehicles, or electric machine parts. When manufacturing from a material, in the bent R portion of the manufactured press-molded product, shape failure such as excessive curvature radius or cracking may occur, and in order to solve these problems, Experiments and research proceeded. As a result, the press molding is divided into a drawing process and a post-finishing process, and the radius of curvature of the bent portion R of the semi-processed product at the end of the drawing process is set to the folding of the press-molded product after the post-finishing process. It has been found that the problem can be suppressed by forming the radius of curvature larger than the radius of curvature of the curved portion R, and a patent application including the technical contents was previously filed as Japanese Patent Application No. 2009-68471.

  Certainly, when a press-molded product is manufactured by the method described in this Japanese Patent Application No. 2009-68471, shape failure such as excessive curvature radius or cracking occurs in the bent R portion of the manufactured press-molded product. Although it was possible to suppress them, it was found that they could not be suppressed reliably, and it was decided to continue with diligence, experimentation and research. As a result, the press molding is divided into a drawing process and a post-finishing process, and the radius of curvature of the bent portion R of the semi-processed product at the end of the drawing process is set to the folding of the press-molded product after the post-finishing process. In addition to forming larger than the radius of curvature of the curved portion R, by forming the depth of the recess of the semi-finished product at the end of the drawing process deeper than the depth of the press-formed product after the end of the finishing process The inventors have found that the occurrence of shape defects such as excessive curvature radius or the occurrence of cracks in the bent R portion of the press-molded product can be more reliably suppressed, and the present invention has been completed.

  Also, the surface temperature of the workpiece including the bending R part during the finishing process, the plate thickness of the workpiece, the half-finished product at the end of the drawing process and the bending of the press-molded product after the finishing process. By defining and controlling the radius of curvature of the R portion in detail, it is possible to more reliably suppress the occurrence of shape defects such as excessive curvature radius of the bent R portion of the press-formed product and the occurrence of cracks. Also found.

  Hereinafter, the present invention will be described in more detail based on embodiments shown in the accompanying drawings.

  A press-formed product 1 manufactured according to the present invention is a molded product such as an automobile panel material. For example, as shown in FIG. 1, a light alloy including an aluminum alloy through a drawing process and a post-processing process in order. It can manufacture from the workpiece 1a made from material. The manufacturing process shown in FIG. 1A is a drawing process, and the manufacturing process shown in FIG. 1B is a subsequent finishing process. In the case of the embodiment shown in FIG. 1, the post-finishing process shown in FIG. 1 (b) is a single bending process, but this bending process may be composed of a plurality of processes, and is particularly illustrated. However, the finishing process may include a trim (cutting) process for cutting the outer peripheral portion of the workpiece 1a into a desired shape and a piercing (drilling) process for making a hole in the workpiece 1a. .

  The manufacturing process shown in FIG. 1 (a) is a drawing process, in which a work material 1a made of a light alloy material such as an aluminum alloy includes a punch 9, a die 10, and a blank holder 11. Is formed into a shape approximate to the final press-formed product 1 to obtain a semi-processed product 1b.

  The manufacturing process shown in FIG. 1 (b) is a post-finishing process (bending process). The workpiece 1a is clamped by applying pressure by sandwiching the workpiece 1a using a pair of pressure bodies 8. This is a step of finishing the final shape, that is, the shape of the desired press-formed product 1.

  The greatest feature of the present invention is the difference in shape between the half-processed product 1b manufactured in the preceding drawing process and the press-formed product 1 finally manufactured in the subsequent finishing process.

  The press-formed product 1 is finished to have a cross-sectional hat shape having a recess 3 surrounded by four side wall portions 4 and a bottom wall portion 5, but at the stage of the half-finished product 1b, the four side wall portions 4 and the bottom are already formed. It is formed into a cross-sectional hat shape having a recess 3 surrounded by a wall 5. In the present specification, the bottom surface of the recess 3 is described as the bottom wall portion 5. In FIG. 1, the recess 3 opens downward and the bottom wall portion 5 appears to be a ceiling surface. The direction of the molded article 1 is merely illustrated with the bottom wall portion 5 facing upward, and may be described with either expression, but in the present specification, the bottom wall portion 5 is consistently described. . In addition, it has been described above that the recess 3 is surrounded by the four side wall portions 4 and the bottom wall portion 5, but the recess 3 is only surrounded by the two opposite side wall portions 4 and the bottom wall portion 5. May be.

  The difference in shape between the half-processed product 1b and the press-formed product 1 that is the greatest feature of the present invention is the following two points. First, the first point is the difference in the depth of the recess 3 between the semi-processed product 1b and the press-formed product 1, and the second point is a corner portion (punch shoulder) between the side wall portion 4 and the bottom wall portion 5. 2a and / or the radius of curvature of the corner portion (die shoulder) 2b between the side wall portion 4 and the flange portion 6, that is, the bent R portion 2. These differences will be described in detail later. In addition, 7 formed at the front-end | tip of the flange part 6 of the press molded product 1 is a rib.

  In the post-finishing step shown in FIG. 1 (b), the workpiece 1 is sandwiched between a pair of pressure bodies 8 in a state including the bent R portion 2 described above. At least one of the pressure bodies 8 is a heating body 8a. The heating body 8a sandwiches the workpiece 1a in the post-finishing process and generates heat as shown in FIG. The bent R portion 2 once formed in the previous drawing process is formed into an R shape having a smaller radius of curvature. The correction for forming the bent R portion 2 into an R shape having a smaller radius of curvature can be performed more reliably when both of the pair of pressure bodies 8 are the heating bodies 8a. In addition, although the site | part demonstrated as the bending R part 2 in this specification is the corner part (punch shoulder) 2a between the side wall part 4 and the bottom wall part 5 which mainly form the recess 3, Accordingly, the corner portion (die shoulder) 2b between the side wall portion 4 and the flange portion 6 may be included, or only the die shoulder 2b may be included.

  Further, the heating by the heating body 8a can also correct wrinkles formed on the surface of the workpiece 1a in the former drawing process and springback generated in the workpiece 1a after the drawing process. .

  The surface temperature of the workpiece 1, in particular, the surface temperature of the bent R portion 2 is heated to 200 to 300 ° C. by the heating body 8 a, so that the punch shoulder 2 a can have a desired radius of curvature. It is desirable to be able to do it.

  When the surface temperature of the workpiece 1a when heated by the heating body 8a is less than 200 ° C., there is little influence on the material strength, and the shape correction effect of the bent R portion 2 is obtained by reducing the deformation resistance of the material. I can't. On the other hand, when the surface temperature of the workpiece 1a exceeds 300 ° C., it is difficult to heat and maintain the temperature by the heating body 8a. Therefore, the surface temperature of the workpiece 1a when heated by the heater 8a is set to 200 to 300 ° C.

  The pressure applied by the pressurizing member 8 is not particularly limited, and the radius of curvature of the bent R portion 2 once formed in the drawing process can be obtained regardless of the pressure applied to the workpiece 1a. Although it can be formed into a shape with a smaller radius of curvature, the applied pressure is preferably 50 MPa or less from the viewpoint of mold strength.

  There is no particular limitation on the pressurizing time in the pressurizing body 8. Even if it is released immediately after reaching the required pressing force, the radius of curvature of the bent R portion 2 once formed in the drawing step can be formed into a shape having a smaller radius of curvature. Even if pressurization is performed for 5 seconds or more, the effect is saturated and the productivity is lowered. Therefore, although the upper limit is not limited, pressurization of less than 5 seconds is sufficient.

  The temperature of the heating body 8a is independently controlled by heating means such as a sheathed heater embedded therein. The heating means for the heating body 8a may be any heating means such as induction heating or energization heating.

  In addition, it is desirable that the entire pressure body 8 is configured to generate heat and is a heating body 8a. However, at least a portion of the surface of the pressure body 8 that contacts the bent R portion 2 generates heat. What is necessary is just to be comprised so that it can do. Moreover, it is desirable that the surface of the heating body 8a be subjected to surface treatment for preventing seizure. Examples of the surface treatment include hard chrome plating, TD treatment, PVD (TiC, TiN, TiAlN), and CVD (TiC, TiN, TiCN, DLC).

  The light alloy material used for the light alloy material press-molded product manufacturing method of the present invention is not particularly defined, but aluminum alloys, in particular, 3000 series aluminum alloys, 5000 series aluminum alloys, and 6000 series aluminum alloys used for automobile parts are used. It is effective to use.

  As described above, the press-formed product 1 is manufactured through the semi-processed product 1b by the drawing process and the post-finishing process. However, after the drawing process is completed, the shape of the semi-processed product 1b and the post-finishing process are completed. There should be no significant difference in the shape of the press-formed product 1, and an appropriate range must be defined for the difference.

  However, the range of the difference between the depth of the recess 3 and the radius of curvature of the bent R portion 2 in the half-processed product 1b and the press-formed product 1 cannot be defined individually. The conditions also differ depending on whether the bent R portion 2 to be corrected is the punch shoulder 2a alone, the die shoulder 2b alone, or both the punch shoulder 2a and the die shoulder 2b.

  Therefore, when the bent R portion 2 to be corrected is a punch shoulder 2a alone, a die shoulder 2b alone, or both a punch shoulder 2a and a die shoulder 2b, the half-processed product 1b at the end of the drawing process is divided. And the range of the difference in the shape of the press-formed product 1 after completion of the post-finishing process was defined by a conditional expression.

When the bent R portion 2 to be corrected is processed by the punch shoulder 2a alone when processing from the semi-processed product 1b to the press-formed product 1, the radius of curvature of the punch shoulder 2a of the semi-processed product 1b at the end of the molding process is Rp. (Unit: mm), the radius of curvature of the punch shoulder 2a of the press-formed product 1 after completion of the post-finishing process is rp (unit: mm), and the depth difference between the recesses 3 of the half-processed product 1b and the press-formed product 1 is When L (unit: mm)
0.02 <(L / Rp) × (rp / Rp) <0.08
On the condition that the relationship is established.

  When (L / Rp) × (rp / Rp) is 0.02 or less, the radius of curvature when processing from the semi-processed product 1b to the press-formed product 1 becomes excessive, and the recess 3 compensates for the amount of change. The difference in the depth becomes insufficient, and cracking occurs during processing from the semi-processed product 1b to the press-formed product 1.

  On the other hand, when (L / Rp) × (rp / Rp) exceeds 0.08, the depth difference L of the recess 3 becomes excessive with respect to the amount of change in radius of curvature (rp / Rp), and the bottom wall The material becomes excessive in the portion 5 and buckling occurs, resulting in poor surface quality. In addition, when the variation | change_quantity (rp / Rp) of a curvature radius is large, it can shape | mold, without providing the difference L of the depth of the recess 3. FIG.

When the bent R portion 2 to be straightened when processing from the semi-processed product 1b to the press-formed product 1 is the die shoulder 2b alone, the radius of curvature of the die shoulder 2b of the semi-processed product 1b at the end of the molding process is Rd. (Unit: mm), the radius of curvature of the die shoulder 2b of the press-formed product 1 after completion of the post-finishing process is rd (unit: mm), and the difference in the depth of the recess 3 between the semi-processed product 1b and the press-formed product 1 When L (unit: mm)
0.02 <(L / Rd) × (rd / Rd) <0.08
On the condition that the relationship is established.

  When (L / Rd) × (rd / Rd) is 0.02 or less, the radius of curvature when processing from the semi-processed product 1b to the press-formed product 1 becomes excessive, and the recess 3 compensates for the amount of change. The difference in the depth becomes insufficient, and cracking occurs during processing from the semi-processed product 1b to the press-formed product 1.

  On the other hand, when (L / Rd) × (rd / Rd) exceeds 0.08, the depth difference L of the recess 3 becomes excessive with respect to the amount of change in radius of curvature (rp / Rp), and the bottom wall The material becomes excessive in the portion 5 and buckling occurs, resulting in poor surface quality. If the amount of change in radius of curvature (rd / Rd) is large, molding can be performed without providing the depth difference L of the recess 3.

When processing from the semi-processed product 1b to the press-formed product 1 and the bent R portion 2 to be corrected is both the punch shoulder 2a and the die shoulder 2b, the punch shoulder of the semi-processed product 1b at the end of the molding process The radius of curvature of 2a is Rp (unit: mm), the radius of curvature of the punch shoulder 2a of the press-formed product 1 after completion of the post-finishing process is rp (unit: mm), and the die shoulder 2b of the semi-processed product 1b at the end of the forming process Rd (unit: mm), the radius of curvature of the die shoulder 2b of the press-formed product 1 after completion of the post-finishing process is rd (unit: mm), and the half-processed product 1b and the recess 3 of the press-formed product 1 When the difference in depth is L (unit: mm),
0.005 <{L ² /(Rp×Rd)}×(rp/Rp)×(rd/Rd)<0.02
On the condition that the relationship is established.

When {L ² / (Rp × Rd)} × (rp / Rp) × (rd / Rd) is 0.005 or less, the radius of curvature when processing from the semi-processed product 1b to the press-formed product 1 becomes excessive. In addition, the difference in the depth of the recess 3 that compensates for the amount of change becomes insufficient, and cracks occur during processing from the semi-processed product 1b to the press-formed product 1.

On the other hand, when {L ² / (Rp × Rd)} × (rp / Rp) × (rd / Rd) exceeds 0.02, the difference L in the depth of the recess 3 with respect to the amount of change in the radius of curvature. Becomes excessive, the material becomes excessive at the bottom wall 5 and buckling occurs, resulting in poor surface quality. In addition, when the variation | change_quantity of a curvature radius is large, it can shape | mold without providing the difference L of the depth of the recess 3.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, and the present invention is implemented with appropriate modifications within a range that can meet the gist of the present invention. These are all included in the technical scope of the present invention.

Example 1
In Example 1, a 6000 series aluminum alloy plate having a plate thickness of 1.0 mm was used to produce a press-formed product having a hat-shaped cross section having a recess surrounded by four side walls and a bottom wall. First, press forming was performed in the drawing process, and semi-processed products having a hat-shaped cross section and depths of recesses of 26 mm (Invention Example 1) and 25 mm (Comparative Example 1) were produced. The curvature radius of the bent R portion (punch shoulder) between the side wall portion and the bottom wall portion of these semi-processed products was set to R10 mm. Subsequently, under the condition of a room temperature of 25 ° C., the process proceeds to a post-finishing process. In both Invention Example 1 and Comparative Example 1, the depth of the recess is 25 mm, and the curvature radius of the bent R portion (punch shoulder) is R3 mm. A bending process (press molding) was performed to obtain a press molded product.

  After observing the bent R part (punch shoulder) between the side wall and bottom wall of the press-molded product after the finishing process, the depth of the recess in the semi-finished product at the end of the drawing process In Invention Example 1 formed 1 mm deeper than the depth of the press-formed product after the finishing process, no cracks were observed in the bent R portion (punch shoulder) between the side wall portion and the bottom wall portion. In Comparative Example 1 in which the depth of the recess of the semi-processed product at the end of the forming process is the same as the depth of the press-formed product after the end of the post-finishing process, the bent R portion between the side wall portion and the bottom wall portion ( The occurrence of cracks in the punch shoulder was confirmed. Inventive example 1 satisfies (L / Rp) × (rp / Rp) = 0.03, and satisfies the condition of 0.02 <(L / Rp) × (rp / Rp) <0.08.

(Example 2)
In Example 2, a 6000 series aluminum alloy plate having a plate thickness of 1.0 mm was used to manufacture a press-formed product having a hat-shaped cross section having a recess surrounded by four side walls and a bottom wall. First, press forming was performed in the drawing process, and semi-processed products having a hat-shaped cross section and a recess depth of 27 mm (Invention Example 2) and 25 mm (Comparative Example 2) were produced. The curvature radius of the bent R portion (punch shoulder) between the side wall portion and the bottom wall portion of these semi-processed products was set to R10 mm. Subsequently, the process proceeds to a post-finishing step, and the depth of the recesses is both in Invention Example 2 and Comparative Example 2 in a state where the surface temperature including the bent R portion (punch shoulder) of the workpiece is heated to 200 ° C. Bending (press molding) was performed so that the radius of curvature of the bent R portion (punch shoulder) was 25 mm, and a press molded product was obtained.

  After observing the bent R part (punch shoulder) between the side wall and bottom wall of the press-molded product after the finishing process, the depth of the recess in the semi-finished product at the end of the drawing process In Invention Example 2 formed 2 mm deeper than the depth of the press-formed product after the finishing process, no cracks were observed in the bent R portion (punch shoulder) between the side wall portion and the bottom wall portion. In Comparative Example 2 in which the depth of the recess of the semi-processed product at the end of the forming process is the same as the depth of the press-formed product after the end of the post-finishing process, the bent R portion between the side wall portion and the bottom wall portion ( The occurrence of cracks in the punch shoulder was confirmed. Inventive example 2 satisfies (L / Rp) × (rp / Rp) = 0.04, and satisfies the condition of 0.02 <(L / Rp) × (rp / Rp) <0.08.

(Example 3)
In Example 3, a 6000 series aluminum alloy plate having a plate thickness of 1.0 mm was used to produce a press-formed product having a hat-shaped cross section having a recess surrounded by four side walls and a bottom wall. First, press forming was performed in the drawing process, and semi-processed products having a hat-shaped cross section and a recess depth of 28 mm (Invention Example 3) and 25 mm (Comparative Example 3) were produced. The radius of curvature of the bent portion R (punch shoulder) between the side wall portion and the bottom wall portion of these semi-finished products is R10 mm, and the radius of curvature of the bent R portion (die shoulder) between the side wall portion and the flange portion is set. Are both R5 mm. Then, it moved to a post-finishing process, and both the invention example 3 and the comparative example 3 were in the state where the surface temperature including the said bending R part (a punch shoulder and a die shoulder) of a workpiece was heated to 200 degreeC. Bending (press molding) was performed so that the depth was 25 mm and the radius of curvature of all bent R portions (punch shoulder and die shoulder) was R2 mm, to obtain a press-molded product.

After observing the bent R part (punch shoulder) between the side wall part and the bottom wall part and the bent R part (die shoulder) between the side wall part and the flange part of the press-molded product after finishing the finishing process, In Invention Example 3 in which the depth of the recess of the semi-processed product at the end of the molding process is 3 mm deeper than the depth of the press-molded product after the end of the post-finishing process, these bent R portions (punch shoulder and die shoulder) are formed. In Comparative Example 3 in which the depth of the recess of the semi-processed product at the end of the drawing process was the same as the depth of the press-formed product after the end of the finishing process, no side wall was generated. The occurrence of cracks in the bent R portion between the bottom wall and the bottom wall (punch shoulder) was confirmed. Inventive Example 3 is {L ² /(Rp×Rd)}×(rp/Rp)×(rd/Rd)=0.007, and 0.005 <{L ² / (Rp × Rd)} The condition of x (rp / Rp) × (rd / Rd) <0.02 is satisfied.

Example 4
In Example 4, a 6000 series aluminum alloy plate having a plate thickness of 1.0 mm was used to manufacture a press-formed product having a hat-shaped cross section having a recess surrounded by four side walls and a bottom wall. First, press forming was performed in a drawing process, and semi-processed products having a hat-shaped cross section and depths of recesses of 28 mm (Invention Example 4) and 25 mm (Comparative Example 4) were produced. The radius of curvature of the bent portion R (punch shoulder) between the side wall portion and the bottom wall portion of these semi-finished products is R10 mm, and the radius of curvature of the bent R portion (die shoulder) between the side wall portion and the flange portion is set. Are both R10 mm. Then, it moved to a post-finishing process, and both the invention example 3 and the comparative example 3 were in the state where the surface temperature including the said bending R part (a punch shoulder and a die shoulder) of a workpiece was heated to 300 degreeC. Bending (press molding) was performed so that the depth was 25 mm, and the radius of curvature of all bent R portions (punch shoulder and die shoulder) was R3 mm, to obtain a press molded product.

After observing the bent R part (punch shoulder) between the side wall part and the bottom wall part and the bent R part (die shoulder) between the side wall part and the flange part of the press-molded product after finishing the finishing process, In Invention Example 4 in which the depth of the recess of the semi-processed product at the end of the molding process is 3 mm deeper than the depth of the press-molded product after the end of the post-finishing process, these bent R portions (punch shoulder and die shoulder) are formed. In Comparative Example 3 in which the depth of the recess of the semi-processed product at the end of the drawing process was the same as the depth of the press-formed product after the end of the finishing process, no side wall was generated. The occurrence of cracks in the bent R portion between the bottom wall and the bottom wall (punch shoulder) was confirmed. Inventive Example 4 is {L ² /(Rp×Rd)}×(rp/Rp)×(rd/Rd)=0.008, and 0.005 <{L ² / (Rp × Rd)} The condition of x (rp / Rp) × (rd / Rd) <0.02 is satisfied.

DESCRIPTION OF SYMBOLS 1 ... Press-formed product 1a ... Work material 1b ... Semi-processed product 2 ... Bending R part 2a ... Corner part (punch shoulder)
2b ... Corner (die shoulder)
DESCRIPTION OF SYMBOLS 3 ... Recess 4 ... Side wall part 5 ... Bottom wall part 6 ... Flange part 7 ... Rib 8 ... Pressurizing body 8a ... Heating body 9 ... Punch 10 ... Die 11 ... Blank holder

Claims (5)

A light alloy material press-molded product manufacturing method for manufacturing a press-molded product having a recess surrounded by a side wall and a bottom wall through press molding from a workpiece made of a lightweight alloy material,
The press molding is composed of a drawing process and a post-finishing process,
The depth of the recess of the semi-processed product at the end of the drawing process is formed deeper than the depth of the press-formed product after the end of the finishing process,
Made of light alloy material, characterized in that the radius of curvature of the bent R portion of the semi-finished product at the end of the drawing process is larger than the radius of curvature of the bent R portion of the press-formed product after the finishing process. Manufacturing method of press-molded products. In the post-finishing step, at least one of the pair of pressure bodies that sandwich the workpiece including the bent R portion is used as a heating body,
2. The light alloy material according to claim 1, wherein the post-finishing step is performed in a state where the surface temperature including the bent portion of the workpiece is heated to 200 to 300 ° C. with the heating body. Manufacturing method of press-molded products. The bent portion R of the press-formed product is a punch shoulder,
The radius of curvature of the punch shoulder of the half-finished product at the end of the drawing process is Rp, the radius of curvature of the punch shoulder of the press-molded product after completion of the post-finishing process is rp, and the depth of the recess between the half-processed product and the press-formed product When the difference in length is L,
The method for producing a press-formed product made of a light alloy material according to claim 1, wherein a relationship of 0.02 <(L / Rp) × (rp / Rp) <0.08 is established. The bent R part of the press-formed product is a die shoulder,
The radius of curvature of the die shoulder of the half-finished product at the end of the drawing process is Rd, the radius of curvature of the die shoulder of the press-molded product after completion of the post-finishing process is rd, and the depth of the recess between the half-processed product and the press-molded product When the difference in length is L,
The method for producing a press-formed product made of a light alloy material according to claim 1, wherein a relationship of 0.02 <(L / Rd) × (rd / Rd) <0.08 is established. The bent portion R of the press-formed product is a punch shoulder and a die shoulder,
The radius of curvature of the punch shoulder of the semi-processed product at the end of the drawing process is Rp, the radius of curvature of the punch shoulder of the press-molded product after the end of the post-finishing process is rp, and the die of the semi-processed product at the end of the drawing process When the radius of curvature of the shoulder is Rd, the radius of curvature of the die shoulder of the press-formed product after completion of the post-finishing process is rd, and the difference in the depth of the recess between the half-processed product and the press-formed product is L,
The light alloy material according to claim 1, wherein a relationship of 0.005 <{L ² /(Rp×Rd)}×(rp/Rp)×(rd/Rd)<0.02 is established. Manufacturing method for press-molded products.

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